Tootfinder

A New Population of Point-like, Narrow-line Objects Revealed by the James Webb Space Telescope
Haojing Yan (University of Missouri-Columbia), Bangzheng Sun (University of Missouri-Columbia), Riley Shive (University of Missouri-Columbia)
https://arxiv.org/abs/2509.12177

A New Population of Point-like, Narrow-line Objects Revealed by the James Webb Space Telescope
We report a new population of objects discovered using the data from the James Webb Space Telescope, which are characterized by their point-like morphology and narrow permitted emission lines. Our sample includes nine objects found in three JWST wide survey fields, which have z=3.624 to 5.378 and M_B ~ -18.3 to -21.4 mag. Their light distributions follow gaussian profiles, with the full-width-at-half-maximum (FWHM) values only 3.7%--34.6% larger than those of the point spread functions. Their s…

Hydrocarbon Hazes on Temperate sub-Neptune K2-18b supported by data from the James Webb Space Telescope
Ruohan Liu, Panayotis Lavvas, Giovanna Tinetti, Jesus Maldonado, Sushuang Ma, Arianna Saba
https://arxiv.org/abs/2509.10947

Hydrocarbon Hazes on Temperate sub-Neptune K2-18b supported by data from the James Webb Space Telescope
K2-18b, a sub-Neptune orbiting in the habitable zone of an M dwarf, has attracted significant interest following observations with the Hubble Space Telescope (HST) and, more recently, with the James Webb Space Telescope (JWST) that reveal detectable atmospheric features. Previous studies have examined a wide range of possible compositions, focusing primarily in the near-infrared (0.8-5.2 $μ$m) or mid-infrared (5-12 $μ$m) wavelengths. We present a new interpretation of K2-18b's JWST transit sp…

Weltraumteleskop James Webb bildet erstmals Exoplaneten direkt ab
Das Weltraumteleskop James Webb hat schon einige Entdeckungen geliefert. Nun wurde damit auch erstmals ein Exoplanet direkt abgebildet, kleinere sollen folgen.

The Type II SN 2025pht in NGC 1637: A Red Supergiant with Carbon-rich Circumstellar Dust as the First JWST Detection of a Supernova Progenitor Star
Charles D. Kilpatrick, Aswin Suresh, Kyle W. Davis, Maria R. Drout, Ryan J. Foley, Alexander Gagliano, Wynn V. Jacobson-Galan, Ravjit Kaur, Kirsty Taggart, Jason Vazquez
https://arxiv.org/abs/2…

The Type II SN 2025pht in NGC 1637: A Red Supergiant with Carbon-rich Circumstellar Dust as the First JWST Detection of a Supernova Progenitor Star
We present follow-up imaging and spectroscopy and pre-explosion imaging of supernova (SN) 2025pht located in NGC 1637 at 12 Mpc. Our spectroscopy shows that SN 2025pht is a Type II SN with broad lines of hydrogen and with minimal line-of-sight extinction inferred from Na I D absorption. NGC 1637 was the target of several epochs of Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) imaging covering the site of SN 2025pht from 31 to 0.7 yr prior to discovery. Using a follow-up HST…

Space Mission Options for Reconnaissance and Mitigation of Asteroid 2024 YR4
Brent W. Barbee, Matthew A. Vavrina, Rylie Bull, Adrienne Rudolph, Davide Farnocchia, Russell TerBeek, Justin Atchison, Joshua Lyzhoft, Jessie Dotson, Patrick King, Paul W. Chodas, Dawn Graninger, Ronald G. Mink, Kathryn M. Kumamoto, Jason M. Pearl, Mary Burkey, Isaiah Santistevan, Catherine S. Plesko, Wendy K. Caldwell, Megan Harwell

Space Mission Options for Reconnaissance and Mitigation of Asteroid 2024 YR4
Near-Earth asteroid 2024 YR4 was discovered on 2024-12-27 and its probability of Earth impact in December 2032 peaked at about 3% on 2025-02-18. Additional observations ruled out Earth impact by 2025-02-23. However, the probability of lunar impact in December 2032 then rose, reaching about 4% by the end of the apparition in May 2025. James Webb Space Telescope (JWST) observations on 2025-03-26 estimated the asteroid's diameter at 60 +/- 7 m. Studies of 2024 YR4's potential lunar impact effects …

Some recent news about the butterfly nebulae…. https://www.esa.int/Science_Exploration/Space_Science/Webb/Webb_investigates_complex_heart_of_a_cosmic_butterfly
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Webb investigates complex heart of a cosmic butterfly
The NASA/ESA/CSA James Webb Space Telescope has revealed new details in the core of the Butterfly Nebula, NGC 6302. From the dense, dusty torus that surrounds the star hidden at the centre of the nebula to its outflowing jets, the Webb observations reveal many new discoveries that paint a never-before-seen portrait of a dynamic and structured planetary nebula.

JWST NIRCam Imaging of NGC 4258: I. Observation Overview
Travis C. Fischer, Nicholas F. Cothard, Omnarayani Nayak, Henrique Schmitt, Erin Smith, Jason Glenn
https://arxiv.org/abs/2508.11044

JWST NIRCam Imaging of NGC 4258: I. Observation Overview
We present James Webb Space Telescope (JWST) NIRCam imaging of the nearby Seyfert 1.9 galaxy NGC 4258, which hosts strong star formation regions as well as an anomalous jet-like radio structure that extends through a significant portion of its disk. This galaxy provides a unique environment to study Active Galactic Nucleus (AGN)-driven shocks and their impact on the interstellar medium (ISM) as its proximity allows for narrow-band observations of various near-infrared tracers sensitive to multi…

Exoplanet: Erdähnliche Atmosphäre nach Analyse bei TRAPPIST-1e noch möglich
Um TRAPPIST-1 kreisen gleich sieben Gesteinsplaneten. Das Weltraumteleskop James Webb hat jetzt einen der spannendsten ins Visier genommen und weckt Neugier.

Supermassive Stars Match the Spectral Signatures of JWST's Little Red Dots
Devesh Nandal, Abraham Loeb
https://arxiv.org/abs/2507.12618 https://…

Supermassive Stars Match the Spectral Signatures of JWST's Little Red Dots
The James Webb Space Telescope (JWST) has unveiled a population of enigmatic, compact sources at high redshift known as ''Little Red Dots'' (LRDs), whose physical nature remains a subject of intense debate. Concurrently, the rapid assembly of the first supermassive black holes (SMBHs) requires the formation of heavy seeds, for which supermassive stars (SMSs) are leading theoretical progenitors. In this work, we perform the first quantitative test of the hypothesis that LRDs are the direct obser…

The Hubble constant from the improved lens modeling of cluster-lensed supernova Refsdal with new spectroscopic redshifts and the Jackknife method
Yuting Liu, Masamune Oguri
https://arxiv.org/abs/2509.09979

The Hubble constant from the improved lens modeling of cluster-lensed supernova Refsdal with new spectroscopic redshifts and the Jackknife method
Time-delay cosmology offers an alternative approach to measuring the Hubble constant ($H_0$), which is distinct from the cosmic distance ladder and cosmic microwave background radiation methods. In this study, we present an improved strong lens mass modeling analysis of the cluster-lensed supernova Refsdal, incorporating the latest spectroscopic redshift data from the MUSE on the Very Large Telescope and the James Webb Space Telescope CANUCS/Technicolor. The robustness of our lens models is con…

The Photochemical Plausibility of Warm Exo-Titans Orbiting M-Dwarf Stars
Sukrit Ranjan, Nicholas F. Wogan, Ana Glidden, Jingyu Wang, Kevin B. Stevenson, Nikole Lewis, Tommi Koskinen, Sara Seager, Hannah R. Wakeford, Roeland P. van der Marel
https://arxiv.org/abs/2509.10611

The Photochemical Plausibility of Warm Exo-Titans Orbiting M-Dwarf Stars
The James Webb Space Telescope (JWST) has begun to spectrally characterize small exoplanets orbiting M-dwarf stars, but interpretation of these spectra is ambiguous, with stellar, instrumental, or atmospheric origins possible for apparent spectral features. Consequently, interpretation of JWST small exoplanet spectra follows a Bayesian approach, with less theoretically plausible interpretations facing a higher burden of proof. Here, we use photochemical modeling to evaluate the plausibility of …

JWST/NIRCam imaging of the Bipolar Planetary Nebula NGC 6537: the (Infra)red Spider, Revealed
Joel Kastner (Rochester Institute of Technology, USA), Paula Moraga Baez (RIT), Bruce Balick (University of Washington, USA), Rodolfo Montez Jr. (CfA/SAO, USA), Caroline Geiser (Max Planck Institute, Germany), Mikako Matsuura (Cardiff University, UK), Jason Nordhaus (RIT), Miguel Santander-Garcia (OAN, Spain)

JWST/NIRCam imaging of the Bipolar Planetary Nebula NGC 6537: the (Infra)red Spider, Revealed
We present James Webb Space Telescope (JWST) near-infrared (NIRCam) Br$α$, H$_2$, [Fe II], and PAH imaging of the molecule-rich, high-excitation bipolar planetary nebula (PN) NGC 6537 (the Red Spider), complemented by new ALMA and Chandra observations and archival HST images. The resulting multiwavelength view of the Red Spider establishes the detailed lobe/torus structure of the nebula and the mass-loss history of its progenitor star. The extinction-penetrating JWST/NIRCam Br$α$ and PAH and …

A previously unknown regular satellite of #Uranus has been detected in a series of images obtained by the Near-Infrared Camera (NIRCam) onboard the James Webb Space Telescope on 2025 Feb. 2: http://www.cbat.eps.harvard.edu/iau/cbet/005500/CBET005593.txt -> https://science.nasa.gov/blogs/webb/2025/08/19/new-moon-discovered-orbiting-uranus-using-nasas-webb-telescope/ - the object is located at a projected radial distance of 56250 /- 250 km from Uranus' center in the planet's equatorial plane, initial astrometry is consistent with the moon orbiting on a nearly circular orbit with an orbital period 0.402 days, and the observed IR flux from the object indicates a radius of 4 - 5 km, placing it well below the detection threshold of earlier images from Voyager and the Hubble Space Telescope.

Characterizing the interplay between Galactic star formation and ionization feedback with PRIMA
Annie Zavagno, Delphine Russeil, Paolo Suin, Siju Zhang, Ram Kesh Yadav, Miguel Figueira, Loris Berthelot, Doris Arzoumanian, Manash Ranjan Samal, Vineet Rawat, Philippe Andr\'e, Michael Mattern, Hong-Li Liu, Sarah Sadavoy, Parisa Nozari, Beno\^it Epinat
https://…

Characterizing the interplay between Galactic star formation and ionization feedback with PRIMA
Recent results from the James Webb Space Telescope show that nearby spiral galaxies are dominated by the presence of H I and H II bubbles that strongly shape their surrounding medium. These bubbles result from the feedback of high-mass stars at different stages of their life cycle. However, early (pre-supernova) feedback from high-mass stars is still poorly quantified. Recent results from numerical simulations suggest that the impact of high-mass star early feedback (photoionization, wind) on s…

James Webb Space Telescope observations of the white dwarf cooling sequence of 47 Tucanae
M. Salaris (Liverpool John Moores University, INAF-OAAb), M. Scalco (INAF-OAPD), L. R. Bedin (INAF-OAPD), S. Cassisi (INAF-OAAb, INFN-Pisa)
https://arxiv.org/abs/2506.20732

James Webb Space Telescope observations of the white dwarf cooling sequence of 47 Tucanae
We present a study of the white dwarf (WD) cooling sequence of the globular cluster 47 Tucanae (47 Tuc or NGC 104) using deep infrared observations with the James Webb Space Telescope (JWST). By combining these data with ultra-deep optical imaging from the Hubble Space Telescope (HST) taken ~12 years earlier, we derived precise proper motions (PMs) and isolated a clean sample of WD cluster members. We estimated the cluster's age by comparing the observed WD cooling sequence luminosity function …

Evidence of Galactic Center Expansion from Gaia DR3 Stars along the South North Axis: Implications for the JWST Early Galaxy Problem
G. S. Karapetian, L. E. Byzalov, M. A. Hovhannisyan, L. A. Mahtessian, A. P. Mahtessian
https://arxiv.org/abs/2509.10856

Evidence of Galactic Center Expansion from Gaia DR3 Stars along the South North Axis: Implications for the JWST Early Galaxy Problem
Recent observations with the James Webb Space Telescope (JWST) have revealed massive, evolved galaxies only a few hundred million years after the Big Bang, challenging standard cosmological models. To test the hypothesis that the Galactic nucleus may act as a source of matter and energy capable of accelerating galaxy formation, we examined whether the Milky Way itself shows signs of central activity. Expansion of the Galactic center would imply such activity in its nuclear region. To investigat…

Noch einige der zuletzt hier besonders häufig geteilten #News:
Wie unsere Erde: Exoplanet TRAPPST-1e könnte eine sekundäre Atmosphäre haben

Clumpiness of galaxies revealed in the near-infrared with COSMOS-Web
Wilfried Mercier, Boris Sindhu Kalita, Marko Shuntov, Rafael C. Arango-Toro, Olivier Ilbert, Laurence Tresse, Yohan Dubois, Clotilde Laigle, Hossein Hatamnia, Nicolas McMahon, Andreas Faisst, Isa Cox, Maxime Trebitsch, Leo Michel-Dansac, Si-Yue Yu, Michaela Hirschmann, Marc Huertas-Company, Arianna Long, Anton Koekemoer, Gr\'egoire Aufort, Joseph Lewis, Ghassem Gozaliasl, R. Michael Rich, Jason Rhodes, Henry Joy M…

Clumpiness of galaxies revealed in the near-infrared with COSMOS-Web
Clumps in the rest-frame UV emission of galaxies have been observed for decades. Since the launch of the James Webb Space Telescope (JWST), a large population is detected in the rest-frame near-infrared (NIR), raising questions about their formation mechanism. We investigate the presence and properties of NIR over-densities (hereafter substructures) in star-forming and quiescent galaxies at 1 < z < 4 to understand their link to the evolution of their host galaxy. We identify substructures in JW…

JWST Reveals a Likely Jellyfish Galaxy at z=1.156
Ian D. Roberts, Michael L. Balogh, Visal Sok, Adam Muzzin, Michael J. Hudson, Pascale Jablonka
https://arxiv.org/abs/2506.14117

JWST Reveals a Likely Jellyfish Galaxy at z=1.156
We report the discovery of COSMOS2020-635829 as a likely jellyfish galaxy undergoing to ram pressure stripping in a (proto)cluster at $z > 1$. High-resolution imaging from the James Webb Space Telescope reveals a symmetric stellar disk coupled to a unilateral tail of star-forming knots to the south. We show that these extra-planar continuum sources are embedded within an ionized gas tail that is kinematically connected to the disk of COSMOS2020-635829. Likely representing the highest-redshift d…

JWST/MIRI observations of the young TWA 27 system: hydrocarbon disk chemistry, silicate clouds, evidence for a CPD
P. Patapis, M. Morales-Calder\'on, A. M. Arabhavi, H. K\"uhnle, D. Gasman, G. Cugno, P. Molli\`e re, E. Matthews, M. M\^alin, N. Whiteford, P. -O. Lagage, R. Waters, M. Guedel, Th. Henning, B. Vandenbussche, O. Absil, I. Argyriou, D. Barrado, P. Baudoz, A. Boccaletti, J. Bouwman, C. Cossou, A. Coulais, L. Decin, R. Gastaud, A. Glasse, A. M. Glauser, S. Grant, M. M…

JWST/MIRI observations of the young TWA 27 system: hydrocarbon disk chemistry, silicate clouds, evidence for a CPD
The Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST) enables the characterisation of young self-luminous gas giants at previously inaccessible wavelengths, revealing physical processes in gas, dust, and clouds. We characterise the young planetary system TWA 27 (2M1207) in the mid-infrared (MIR), studying the atmosphere and disk spectra of the M9 brown dwarf TWA 27A and its L6 planetary-mass companion TWA 27b. We obtained data with the MIRI Medium Resolution Spectrometer (…

Mit dem Weltraumteleskop James Webb: Weiterer kleiner Mond des Uranus entdeckt
Mehr Monde als der Uranus haben im Sonnensystem nur der Jupiter und der Saturn. Nun ist ein weiterer dazugekommen, die Gesamtzahl steigt damit auf jetzt 29.

Little Red Dots from Small-Scale Primordial Black Hole Clustering
Borui Zhang, Wei-Xiang Feng, Haipeng An
https://arxiv.org/abs/2507.07171 https://

Little Red Dots from Small-Scale Primordial Black Hole Clustering
The James Webb Space Telescope (JWST) observations have identified a class of compact galaxies at high redshifts ($4 \lesssim z \lesssim 11$), dubbed "little red dots" (LRDs). The supermassive black holes (SMBHs) of $10^{5-8}{\rm\,M}_{\odot}$ in LRDs favor a heavy-seed origin. We propose a mechanism for their formation: Clusters of primordial black holes, formed through long-short mode coupling on small scales in the early Universe, undergo sequential mergers over extended timescales. This mech…

James Webb Space Telescope Observations of the Nearby and Precisely-Localized FRB 20250316A: A Potential Near-IR Counterpart and Implications for the Progenitors of Fast Radio Bursts
Peter K. Blanchard, Edo Berger, Shion E. Andrew, Aswin Suresh, Kohki Uno, Charles D. Kilpatrick, Brian D. Metzger, Harsh Kumar, Navin Sridhar, Amanda M. Cook, Yuxin Dong, Tarraneh Eftekhari, Wen-fai Fong, Walter W. Golay, Daichi Hiramatsu, Ronniy C. Joseph, Victoria M. Kaspi, Mattias Lazda, Calvin Leung, K…

James Webb Space Telescope Observations of the Nearby and Precisely-Localized FRB 20250316A: A Potential Near-IR Counterpart and Implications for the Progenitors of Fast Radio Bursts
We present deep James Webb Space Telescope near-infrared imaging to search for a quiescent or transient counterpart to FRB 20250316A, which was precisely localized with the CHIME/FRB Outriggers array to an area of $11\times13$ pc in the outer regions of NGC 4141 at $d\approx40$ Mpc. Our F150W2 image reveals a faint source near the center of the FRB localization region ("NIR-1"; $M_{\rm F150W2}\approx-2.5$ mag; probability of chance coincidence $\approx0.36$), the only source within $\approx2.7�…

🔍 Vortrag: Adaptive Optik für das James Webb Space Teleskop
Geschichte und Einblicke in die #Mathematik hinter dem #JWST: Wie wir bis zum Anfang der Zeit zurückblicken können!
⏲ Uhrzeit: 21:30 & 22:00 & 22:40 Uhr
🗓️ Datum: 21.06.2025
⏱ Dauer: 20min
🧑‍🔬 V…

A Machine Learning empowered search for Sub-Minute Optical Transient Events with the Deeper, Wider, Faster programme
Simon R. Goode, Sara A. Webb, Jeff Cooke, Jielai Zhang, James Freeburn, Amy Lien, Mohsen Shamohammadi, Alexandra Rosenthal, Laura N. Driessen, Christopher Fluke, Ashish Mahabal, Anais M\"oller, Dougal Dobie, Adam Batten, Natasha Van Bemmel
h…

A Machine Learning empowered search for Sub-Minute Optical Transient Events with the Deeper, Wider, Faster programme
Optical transient surveys continue to generate increasingly large datasets, prompting the introduction of machine-learning algorithms to search for quality transient candidates efficiently. Existing machine-learning infrastructure can be leveraged in novel ways to search these datasets for new classes of transients. We present a machine-learning accelerated search pipeline for the Deeper, Wider, Faster (DWF) programme designed to identify high-quality astrophysical transient candidates that con…

An optical to infrared study of type II SN2024ggi at nebular times
Luc Dessart, Rubina Kotak, Wynn Jacobson-Galan, Kaustav Das, Christoffer Fremling, Mansi Kasliwal, Yu-Jing Qin, Sam Rose
https://arxiv.org/abs/2507.05803

An optical to infrared study of type II SN2024ggi at nebular times
We present 0.3-21mic observations at ~275d and ~400d for Type II supernova (SN) 2024ggi, combining ground-based optical and near-infrared data from the Keck I/II telescopes and space-based infrared data from the James Webb Space Telescope. Although the optical regions dominate the observed flux, SN2024ggi is bright at infrared wavelengths (65%/35% falls each side of 1mic). SN2024ggi exhibits a plethora of emission lines from H, He, intermediate-mass elements (O, Na, Mg, S, Ar, Ca), and iron-gro…

Dating N loud AGNs at high redshift: GS3073 as a snapshot of wCen like evolution of a nuclear star cluster
F. D'Antona, P. Ventura, A. F. Marino, A. P. Milone, E. Vesperini, F. Calura, M. Tailo, R. Valiante, V. Caloi, A. D'Ercole, F. Dell'Agli
https://arxiv.org/abs/2507.06311…

Dating N loud AGNs at high redshift: GS3073 as a snapshot of wCen like evolution of a nuclear star cluster
In this paper we address two major questions raised by recent James Webb Space Telescope observations of the young Universe, namely: 1) what are the seed initial masses, and how rapidly have supermassive black holes (BHs) with masses of 1e6-1e8Msun grown in active galactic nuclei (AGN) hosted by very young galaxies? 2) What are the plausible explanations for the super solar abundances of nitrogen in a fraction of young galaxies at high redshift, both with and without evidence of a massive centr…

Volcanic Satellites Tidally Venting Na, K, SO2 in Optical & Infrared Light
Apurva V. Oza, Andrea Gebek, Moritz Meyer zu Westram, Armen Tokadjian, Anthony L. Piro, Renyu Hu, Athira Unni, Raghav Chari, Aaron Bello-Arufe, Carl A. Schmidt, Amy J. Louca, Yamila Miguel, Raissa Estrela, Jeehyun Yang, Mario Damiano, Yasuhiro Hasegawa, Luis Welbanks, Diana Powell, Rishabh Garg, Pulkit Gupta, Yuk L. Yung, Rosaly M. C. Lopes

Volcanic Satellites Tidally Venting Na, K, SO2 in Optical & Infrared Light
Recent infrared spectroscopy from the James Webb Space Telescope (JWST) has spurred analyses of common volcanic gases such as carbon dioxide (CO2), sulfur dioxide (SO2), alongside alkali metals sodium (Na I) and potassium (K I) surrounding the hot Saturn WASP-39 b. We report more than an order-of-magnitude of variability in the density of neutral Na, K, and SO2 between ground-based measurements and JWST, at distinct epochs, hinting at exogenic physical processes similar to those sourcing Io's e…

Conceptual Opto-Mechanical design of SHARP: a near-infrared multi-mode spectrograph conceived for the next-generation telescopes
H. Mahmoodzadeh, P. Saracco, P. Conconi, B- Saggin, D- Scaccabarozzi, I. Di Antonio, M. Riva, E. Molinari, C. Arcidiacono, I. Arosio, E. Cascone, V. Cianniello, V. De Caprio, G. Di Rico, B. Di Francesco, C- Eredia, P. Franzetti, M. Fumana, D. Greggio, E. Portaluri, M. Scalera

Conceptual Opto-Mechanical design of SHARP: a near-infrared multi-mode spectrograph conceived for the next-generation telescopes
The next generation of Extremely Large Telescopes (ELTs), with their wide apertures and advanced Multi-Conjugate Adaptive Optics (MCAO) systems, will provide unprecedented sharp and deep observations, even surpassing the capabilities of James Webb Space Telescope (JWST). SHARP, a near-infrared (0.95-2.45 μm) spectrograph, is designed to optimally exploit the collecting area and angular resolution of these forthcoming ELTs, and specifically optimized for the MCAO unit MORFEO at the ELT. SHARP i…

Impact of stochastic star-formation histories and dust on selecting quiescent galaxies with JWST photometry
K. Lisiecki, D. Donevski, A. W. S. Man, I. Damjanov, M. Romano, S. Belli, A. Long, G. Lorenzon, K. Ma{\l}ek, Junais, C. C. Lovell, A. Nanni, C. Bertemes, W. Pearson, O. Ryzhov, M. Koprowski, A. Pollo, S. Dey, H. Thuruthipilly
https://

Impact of stochastic star-formation histories and dust on selecting quiescent galaxies with JWST photometry
While the James Webb Space Telescope (JWST) now allows identifying quiescent galaxies (QGs) out to early epochs, the photometric selection of quiescent galaxy candidates (QGCs) and the derivation of key physical quantities are highly sensitive to the assumed star-formation histories (SFHs). We aim to quantify how the inclusion of JWST/MIRI data and different SFH models impacts the selection and characterisation of QGCs. We test the robustness of the physical properties inferred from the spectra…

Hot springs and dust reservoirs: JWST reveals the dusty, molecular aftermath of extragalactic stellar mergers
Viraj Karambelkar, Mansi Kasliwal, Ryan M. Lau, Jacob E. Jencson, Nadejda Blagorodnova, Marco A. Gomez-Munoz, Hugo Tranin, Maxime Wavasseur, Melissa Shahbandeh, Kishalay De
https://arxiv.org/abs/2508.03932

Hot springs and dust reservoirs: JWST reveals the dusty, molecular aftermath of extragalactic stellar mergers
We present James Webb Space Telescope (JWST) observations of four Luminous Red Novae (LRNe): dusty, extragalactic transients from stellar mergers following common-envelope evolution (CEE) in massive binary stars. Our targets - AT2021blu, AT2021biy, AT2018bwo, and M31-LRN-2015 - span a broad range in progenitor primary masses ($\approx$3-24M$_{\odot}$) and post-merger ages ($\approx$1100-3700 days). All four were observed with the Mid-Infrared Instrument (MIRI) from 5-25$μ$m; AT2021blu and AT20…

The Small Magellanic Cloud through the lens of the James Webb Space Telescope : binaries and mass function within the galaxy outskirts
M. V. Legnardi, F. Muratore, A. P. Milone, G. Cordoni, T. Ziliotto, E. Dondoglio, A. F. Marino, A. Mastrobuono-Battisti, E. Bortolan, E. P. Lagioia, M. Tailo
https://arxiv.org/abs/2509.08687

The Small Magellanic Cloud through the lens of the James Webb Space Telescope : binaries and mass function within the galaxy outskirts
The stellar initial mass function (IMF) and the fraction of binary systems are fundamental ingredients that govern the formation and evolution of galaxies. Whether the IMF is universal or varies with environment remains one of the central open questions in astrophysics. Dwarf galaxies such as the Small Magellanic Cloud (SMC), with their low metallicity and diffuse star-forming regions, offer critical laboratories to address this issue. In this work, we exploit ultra-deep photometry from the Jam…

JWST Discovery of Strong Lensing from a Galaxy Cluster at Cosmic Noon: Giant Arcs and a Highly Concentrated Core of XLSSC 122
Kyle Finner, Sangjun Cha, Zachary P. Scofield, M. James Jee, Yu-heng Lin, Hyungjin Joo, Hyosun Park, Takahiro Morishita, Andreas Faisst, Bomee Lee, Wuji Wang, Ranga-Ram Chary
https://arxiv.org/abs/2508.08356

JWST Discovery of Strong Lensing from a Galaxy Cluster at Cosmic Noon: Giant Arcs and a Highly Concentrated Core of XLSSC 122
Our observations with the James Webb Space Telescope have made the remarkable discovery of strong gravitational lensing arcs from XLSSC 122 ($z=1.98$) - setting the record for the most distant galaxy cluster that exhibits strong lensing. The discovery of giant arcs enables a strong-lensing analysis and a measurement of the concentration of the dark matter halo. We perform a strong-lensing analysis of the cluster and measure the radial projected mass density profile. Our measurements reveal an e…

Stringent constraint on the CCC TL cosmology with $H(z)$ Measurements
Lei Lei (Purple Mountain Observatory, University of Science and Technology of China), Ze-Fan Wang (Purple Mountain Observatory, University of Science and Technology of China), Tong-Lin Wang (Purple Mountain Observatory, University of Science and Technology of China), Yi-Ying Wang (Purple Mountain Observatory), Guan-Wen Yuan (University of Trento, Trento Institute for Fundamental Physics and Applications), Wei-Long Li…

Stringent constraint on the CCC+TL cosmology with $H(z)$ Measurements
Recently, the Covarying Coupling Constants and Tired Light (CCC+TL) hybrid model was proposed to explain the unexpectedly small angular diameters of high-redshift galaxies observed by the James Webb Space Telescope (JWST) that are challenging to reconcile with the $Λ$CDM model. In this work, we test the CCC+TL model against model-independent Hubble parameter [$H(z)$] measurements obtained from cosmic chronometers. It turns out that the parameter set optimized for the type-Ia supernova (SN Ia) …

Spectroscopy of Free-Floating Planetary-Mass Objects and their disks with JWST
Belinda Damian, Aleks Scholz, Ray Jayawardhana, V. Almendros-Abad, Laura Flagg, Koraljka Mu\v{z}i\'c, Antonella Natta, Paola Pinilla, Leonardo Testi
https://arxiv.org/abs/2507.05155

Spectroscopy of Free-Floating Planetary-Mass Objects and their disks with JWST
Free-floating planetary-mass objects (FFPMOs) are known to harbor disks at young ages. Here, we present 1-13 $μm$ spectra for eight young FFPMOs with masses of 5-10 M$_\mathrm{Jup}$ (at ages of 1-5 Myr), using the NIRSpec and MIRI instruments on the James Webb Space Telescope. We derive fundamental properties of these targets, and find spectral types of M9.5 to L4, with effective temperatures of 1600-1900 K. The photospheric spectra of our targets show a clear diversity at similar temperatures…

The Aromatic Infrared Bands around the Wolf-Rayet Binary WR140 Revealed by JWST
Kotomi Taniguchi, Ryan M. Lau, Takashi Onaka, Macarena Garcia Marin, Hideo Matsuhara, Anthony Moffat, Theodore R. Gull, Thomas I. Madura, Gerd Weigelt, Riko Senoo, Alan T. Tokunaga, Walter Duley, Peredur M. Williams, Noel D. Richardson, Joel Sanchez-Bermudez
https://

The Aromatic Infrared Bands around the Wolf-Rayet Binary WR140 Revealed by JWST
We have analyzed the aromatic infrared bands (AIBs) in the 6-11.2 $μ$m range around the Wolf-Rayet binary WR140 (d=1.64 kpc) obtained with the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) Medium-Resolution Spectrometer (MRS). In WR140's circumstellar environment, we have detected AIBs at 6 $μ$m and 7.7 $μ$m which are attributed to C-C stretching modes. These features have been detected in the innermost dust shell (Shell1; ~2100 au from WR140), the subsequent dust shell (S…

Flares on TRAPPIST-1 reveal the spectrum of magnetic features on its surface
Valeriy Vasilyev, Nadiia Kostogryz, Alexander I. Shapiro, Astrid M. Veronig, Benjamin V. Rackham, Christoph Schirninger, Julien de Wit, Ward Howard, Jeff Valenti, Adina D. Feinstein, Olivia Lim, Sara Seager, Laurent Gizon, Sami K. Solanki
https://arxiv.org/abs/250…

Flares on TRAPPIST-1 reveal the spectrum of magnetic features on its surface
TRAPPIST-1 is an M8 dwarf hosting seven known exoplanets and is currently one of the most frequently observed targets of the James Webb Space Telescope (JWST). However, it is notoriously active, and its surface is believed to be covered by magnetic features that contaminate the planetary transmission spectra. The radiative spectra of these magnetic features are needed to clean transmission spectra, but they currently remain unknown. Here, we develop a new approach for measuring these spectra us…

Quantification of The Age Dependence of Mid-Infrared Star Formation Rate Indicators
Daniela Calzetti (Univ. of Massachusetts, MA, USA), Robert C. Kennicutt (Texas A and M, TX, USA, Univ. of Arizona, AZ, USA), Angela Adamo (Univ. of Stockholm, Sweden), Karin Sandstrom (Univ. of California San Diego, CA, USA), Daniel A. Dale (Univ. of Wyoming, WY, USA), Bruce Elmegreen (Katonah, NY, USA), John S. Gallagher (Univ. of Wisconsin-Madison, WI, USA, Macalester Univ., MN, USA), Benjamin Gregg (…

Quantification of The Age Dependence of Mid-Infrared Star Formation Rate Indicators
We combine James Webb Space Telescope images of the nearby galaxy NGC 5194 in the hydrogen recombination line Pa-alpha (lambda=1.8756 micron) from the Cycle 1 program JWST-FEAST with 21 micron dust continuum images from the Cycle 2 Treasury program JWGT to quantify the difference in the calibration of mid-infrared star formation rates (SFR) between HII regions and galaxies. We use the archival HST H-alpha image to correct the Pa-alpha emission for the effects of dust attenuation. Our data confi…

JWST Observations of SN 2023ixf I: Completing the Early Multi-Wavelength Picture with Plateau-phase Spectroscopy
J. M. DerKacy, C. Ashall, E. Baron, K. Medler, T. Mera, P. Hoeflich, M. Shahbandeh, C. R. Burns, M. D. Stritzinger, M. A. Tucker, B. J. Shappee, K. Auchettl, C. R. Angus, D. D. Desai, A. Do, J. T. Hinkle, W. B. Hoogendam, M. E. Huber, A. V. Payne, D. O. Jones, J. Shi, M. Y. Kong, S. Romagnoli, A. Syncatto, S. Moran, E. Fereidouni, P. J. Brown, M. Engesser, O. D. Fox, L. Galb…

JWST Observations of SN 2023ixf I: Completing the Early Multi-Wavelength Picture with Plateau-phase Spectroscopy
We present and analyze panchromatic (0.35-14 $μ$m) spectroscopy of the Type II supernova 2023ixf, including near- and mid-infrared spectra obtained 33.6 days after explosion during the plateau-phase, with the James Webb Space Telescope (JWST). This is the first in a series of papers examining the evolution of SN 2023ixf with JWST spanning the initial 1000 days after explosion, monitoring the formation and growth of molecules and dust in ejecta and surrounding environment. The JWST infrared spe…

Can an Anti-de Sitter Vacuum in the Dark Energy Sector Explain JWST High-Redshift Galaxy and Reionization Observations?
Anirban Chakraborty, Tirthankar Roy Choudhury, Anjan Ananda Sen, Purba Mukherjee
https://arxiv.org/abs/2509.02431

Can an Anti-de Sitter Vacuum in the Dark Energy Sector Explain JWST High-Redshift Galaxy and Reionization Observations?
The James Webb Space Telescope's (JWST) discovery of an unexpectedly high abundance of UV-bright galaxies at redshifts $z > 10$ poses a significant challenge to the standard $Λ$CDM cosmology. This work tests whether this tension can be resolved solely by modifying the cosmological background, without invoking significant evolution in the astrophysical properties of early galaxies. We investigate an alternative framework featuring the presence of an anti-de Sitter vacuum in the dark energy sect…

Reionization in Protocluster Environments at $z>7$ with JWST/NIRSpec
Qiong Li, Christopher J. Conselice, Duncan Austin, Tom Harvey, Nathan Adams, Vadim Rusakov, Lewi Westcott
https://arxiv.org/abs/2508.08037

Reionization in Protocluster Environments at $z>7$ with JWST/NIRSpec
Understanding the role of high-redshift protoclusters in cosmic reionization is essential to unveiling the early stages of structure formation. Using deep imaging and spectroscopy from the James Webb Space Telescope (JWST) JADES Deep Survey in GOODS-South, we identify two prominent protoclusters at z>7 and investigate their environmental properties in comparison to field galaxies. Protocluster members exhibit systematically higher ionizing photon production efficiency ($ξ_{\text{ion}}$) and in…

A search of periodic variable stars in the LMC by JWST photometry
Jiyu Wang, Xiaodian Chen, Jianxing Zhang, Ziming Yan, Shu Wang, Licai Deng
https://arxiv.org/abs/2506.21971

A search of periodic variable stars in the LMC by JWST photometry
Based on high-resolution near-infrared photometric data from the James Webb Space Telescope (JWST) targeting the Large Magellanic Cloud (LMC), this study attempts to evaluate the feasibility and sensitivity limits of variable star detection in crowded stellar fields. Through light curve analysis, we identified a total of 304 periodic variable stars, including 71 EW-type eclipsing binaries, 7 EA-type eclipsing binaries, 177 rotational variables, 38 $δ$ Scuti (DSCT) stars, and 12 RR Lyrae stars.…

A New Approach to Compiling Exoatmospheric Target Lists And Quantifying the Ground-Based Resources Needed to Vet Them
Jennifer A. Burt, Robert T. Zellem, David R. Ciardi, Shubham Kanodia, Geoffrey Bryden, Tiffany Kataria, Kyle A. Pearson, Jessie L. Christiansen, Charles Beichman, B. J. Fulton, Mark Swain
https://arxiv.org/abs/2508.03801

A New Approach to Compiling Exoatmospheric Target Lists And Quantifying the Ground-Based Resources Needed to Vet Them
Transiting exoplanet atmospheric characterization is currently in a golden age as dozens of exoplanet atmospheres are being studied by NASA's Hubble and James Webb Space Telescopes. This trend is expected to continue with NASA's Pandora Smallsat and Roman Space Telescope and ESA's Ariel mission (all expected to launch within this decade) and NASA's Habitable Worlds Observatory (expected to launch in the early 2040s) all of which are centered around studying the atmospheres of exoplanets. Here w…

The Jet Origin of the Mid-infrared Excess in the Black Hole V404 Cygni in Quiescence
E. S. Borowski, R. I. Hynes, Q. Hunt, A. J. Tetarenko, R. M. Plotkin, T. Shahbaz, P. Gandhi, T. J. Maccarone, J. C. A. Miller-Jones, C. O. Heinke, A. W. Shaw, T. D. Russell, G. R. Sivakoff, P. A. Charles, E. V. Palaiologou, P. Reig
https://arxiv…

The Jet Origin of the Mid-infrared Excess in the Black Hole V404 Cygni in Quiescence
Observations of some quiescent black hole X-ray binaries have revealed an excess of mid-infrared (MIR) emission above that expected from their donor stars. In one system, V404 Cygni, this excess has been variously suggested to arise from the accretion disk, circumbinary material, or a compact relativistic jet. Here we present simultaneous James Webb Space Telescope (JWST), Atacama Large Millimeter/submillimeter Array (ALMA), and complementary multi-wavelength observations undertaken to resolve …

Worlds Next Door: A Candidate Giant Planet Imaged in the Habitable Zone of $\alpha$ Cen A. I. Observations, Orbital and Physical Properties, and Exozodi Upper Limits
Charles Beichman, Aniket Sanghi, Dimitri Mawet, Pierre Kervella, Kevin Wagner, Billy Quarles, Jack J. Lissauer, Max Sommer, Mark Wyatt, Nicolas Godoy, William O. Balmer, Laurent Pueyo, Jorge Llop-Sayson, Jonathan Aguilar, Rachel Akeson, Ruslan Belikov, Anthony Boccaletti, Elodie Choquet, Edward Fomalont, Thomas Henning, De…

Worlds Next Door: A Candidate Giant Planet Imaged in the Habitable Zone of $α$ Cen A. I. Observations, Orbital and Physical Properties, and Exozodi Upper Limits
We report on coronagraphic observations of the nearest solar-type star, $α$ Cen A, using the MIRI instrument on the James Webb Space Telescope. With three epochs of observation (August 2024, February 2025, and April 2025), we achieve a sensitivity sufficient to detect $T_{\rm eff}\approx$ 225-250 K (1-1.2 $R_{\rm Jup}$) planets between 1"-2" and exozodiacal dust emission at the level of $>$5-8$\times$ the brightness of our own zodiacal cloud. The lack of exozodiacal dust emission sets an unpre…

Black hole mass function shift in proto-stellar-clusters driven by gas accretion
Zacharias Roupas
https://arxiv.org/abs/2509.08448 https://arxiv.org/pdf/25…

Black hole mass function shift in proto-stellar-clusters driven by gas accretion
The James Webb Space Telescope (JWST) has observed compact, massive proto-stellar clusters of low metallicity in the Cosmic Gems arc galaxy at high redshift, which represent likely precursors to globular clusters. We model the mass growth of stellar black holes (BHs) during the first few Myr of the life of a massive, compact, gaseous stellar cluster before stellar feedback expels the primordial gas. At high redshift, in a lower metallicity environment stellar winds get weaker allowing for large…

First Temperature Profile of a Stellar Flare using Differential Chromatic Refraction
Riley Clarke, Federica Bianco, James R. A. Davenport, Jeffery Cooke, Sara Webb, Igor Andreoni, Tyler Pritchard, Aaron Roodman
https://arxiv.org/abs/2507.19584

First Temperature Profile of a Stellar Flare using Differential Chromatic Refraction
We present the first derivation of a stellar flare temperature profile from single-band photometry. Stellar flare DWF030225.574-545707.45129 was detected in 2015 by the Dark Energy Camera as part of the Deeper, Wider, Faster Programme. The brightness ($Δm_g = -6.12$) of this flare, combined with the high air mass ($1.45 \lesssim X \lesssim 1.75$) and blue filter (DES $g$, 398-548 nm) in which it was observed, provided ideal conditions to measure the zenith-ward apparent motion of the source du…

Explaining the "too massive" high-redshift galaxies in JWST data: numerical study of three effects and a simple relation
Joshua J. Ziegler, Katherine Freese, Jonathan Lozano, Gabriele Montefalcone
https://arxiv.org/abs/2507.21409

Explaining the "too massive" high-redshift galaxies in JWST data: numerical study of three effects and a simple relation
The James Webb Space Telescope has discovered high luminosity galaxies that appear to be "too many" and "too massive" compared to predictions of the Standard LCDM cosmology, suggesting that star formation in the early universe is more rapid than previously anticipated. In this paper we examine in detail the following three effects which can instead provide alternative explanations for these observations: (1) a "top heavy" initial mass function (IMF) for the stars, (2) a variety of star formatio…

Evolution of JWST Contingency Payload Operations for Mitigating NIRSpec Micro-shutter Array Electrical Shorts
Katie Bechtold, Torsten B\"oker, David E. Franz, Dennis Garland, Maurice te Plate, Timothy D. Rawle, Christopher Q. Trinh, Rai Wu, Peter Zeidler
https://arxiv.org/abs/2508.13351

Evolution of JWST Contingency Payload Operations for Mitigating NIRSpec Micro-shutter Array Electrical Shorts
The Near-Infrared Spectrograph (NIRSpec) is one of four science instruments on board the James Webb Space Telescope (JWST), which began routine operations in July 2022. As JWST's primary spectroscopic instrument for faint, distant targets, NIRSpec plays a central role in several of the mission's core science goals. Its signature multi-object spectroscopy (MOS) mode enables the simultaneous acquisition of spectra for up to a hundred targets across the field of view, using a micro-shutter array (…

GA-NIFS: an extended [OIII] halo around the sub-Eddington quasar J1342 0928 at z=7.54
Bartolomeo Trefoloni, Stefano Carniani, Elena Bertola, Giacomo Venturi, Sandra Zamora, Eleonora Parlanti, Santiago Arribas, Andrew Bunker, St\'ephane Charlot, Francesco D'Eugenio, Peter Jakobsen, Roberto Maiolino, Michele Perna, Bruno Rodr\'iguez Del Pino, Hannah \"Ubler, Chris J. Willott, Torsten B\"oker, Giovanni Cresci, Isabella Lamperti, Madeline Marshall, Pablo G. P\'ere…

GA-NIFS: an extended [OIII] halo around the sub-Eddington quasar J1342+0928 at z=7.54
The James Webb Space Telescope (\textit{JWST}) opened a new observational window on the primordial Universe. Here we present new JWST NIRSpec integral field spectroscopy (IFS) observations of the $z=7.54$ quasar ULAS J1342+0928 obtained as part of the Galaxy Assembly with NIRSpec IFS (GA-NIFS) GTO programme. The new data-set obtained with both the prism ($R\sim100$) and the high-resolution grating ($R\sim2700$) allow for a complete description of the quasar emission from the rest-frame UV to op…

Mapping atmospheric features of the planetary-mass brown dwarf SIMP 0136 with JWST NIRISS
Roman Akhmetshyn, Etienne Artigau, Nicolas B. Cowan, Michael K. Plummer, Fei Wang, Ben Burningham, Bjorn Benneke, Rene Doyon, Ray Jayawardhana, David Lafreniere, Stanimir A. Metchev, Jason F. Rowe
https://arxiv.org/abs/2509.00149

Mapping atmospheric features of the planetary-mass brown dwarf SIMP 0136 with JWST NIRISS
In this paper, we analyze James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph time-series spectroscopy data to characterize the atmosphere of the planetary-mass brown dwarf SIMP J01365662+093347. Principal component analysis reveals that 81\% of spectral variations can be described by two components, implying that variability within a single rotational phase is induced by at least three distinct spectral regions. By comparing our data to a grid of Sonora Diamondback atmosp…

Frequent Extreme Galaxy-scale Outflows among Luminous Early Quasars
Weizhe Liu, Xiaohui Fan, Huan Li, Richard Green, Jinyi Yang, Xiangyu Jin, Jianwei Lyu, Maria Pudoka, Yongda Zhu, Eduardo Banados, Silvia Belladitta, Thomas Connor, Tiago Costa, Roberto Decarli, Anna-Christina Eilers, Hyunsung Jun, Madeline A. Marshall, Chiara Mazzucchelli, Jan-Torge Schindler, Yue Shen, Sylvain Veilleux, Julien Wolf, Huanian Zhang, Mingyang Zhuang, Siwei Zou, Mingyu Li

Frequent Extreme Galaxy-scale Outflows among Luminous Early Quasars
The existence of abundant post-starburst/quiescent galaxies just $\sim$1-2 Gyrs after the Big Bang challenges our current paradigm of galaxy evolution. Cosmological simulations suggest that quasar feedback is likely the most promising mechanism responsible for such rapid quenching. Here we report a high detection rate (6/27) of exceptionally fast and powerful galaxy-scale outflows traced by [O III] emission in z $\sim$ 5-6 luminous quasars as revealed by the James Webb Space Telescope (JWST), w…

Rapid late-time reionization: constraints and cosmological implications
Willem Elbers
https://arxiv.org/abs/2508.21069 https://arxiv.org/pdf/2508.21069

Rapid late-time reionization: constraints and cosmological implications
We present constraints on the reionization optical depth, $τ$, obtained using several independent methods. First, we perform a non-parametric reconstruction of the reionization history, using Lyman-$α$ constraints on the evolution of the volume-averaged neutral hydrogen fraction, $x_\mathrm{HI}(z)$, including recent results from the James Webb Space Telescope. When combined with baryon acoustic oscillation (BAO) measurements from DESI and Big Bang nucleosynthesis constraints, these data imply…

Exploring Cosmic Dawn with PANORAMIC I: The Bright End of the UVLF at $z\sim9 -17$
Andrea Weibel, Pascal A. Oesch, Christina C. Williams, Christian Kragh Jespersen, Marko Shuntov, Katherine E. Whitaker, Hakim Atek, Rachel Bezanson, Gabriel Brammer, Iryna Chemerynska, Aidan P. Cloonan, Pratika Dayal, Lukas J. Furtak, Anne Hutter, Zhiyuan Ji, Michael V. Maseda, Mengyuan Xiao
…

Exploring Cosmic Dawn with PANORAMIC I: The Bright End of the UVLF at $z\sim9 -17$
In its first two years of operation, the James Webb Space Telescope has enabled the discovery of a surprising number of UV-bright galaxies at $z\sim10-14$. Their number density is still relatively uncertain, due to cosmic variance effects, and the limited survey area with deep imaging. Here, we combine pure parallel imaging from the PANORAMIC survey with data from legacy fields to constrain the bright end (M$_{\rm UV}<-18.5$) of the UV luminosity function (UVLF) over $0.28\,$deg$^2$ of NIRCam i…

A Panchromatic View of Late-time Shock Power in the Type II Supernova 2023ixf
W. V. Jacobson-Gal\'an, L. Dessart, C. D. Kilpatrick, P. J. Patel, K. Auchettl, S. Tinyanont, R. Margutti, V. V. Dwarkadas, K. A. Bostroem, R. Chornock, R. J. Foley, H. Abunemeh, T. Ahumada, P. Arunachalam, M. J. Bustamante-Rosell, D. A. Coulter, C. Gall, H. Gao, X. Guo, D. O. Jones, J. Hjorth, M. Kaewmookda, M. M. Kasliwal, R. Kaur, C. Larison, N. LeBaron, H. -Y. Miao, G. Narayan, Y. -C. Pan, S. H. Park,…

A Panchromatic View of Late-time Shock Power in the Type II Supernova 2023ixf
We present multi-wavelength observations of the type II supernova (SN II) 2023ixf during its first two years of evolution. We combine ground-based optical/NIR spectroscopy with Hubble Space Telescope (HST) far- and near-ultraviolet spectroscopy and James Webb Space Telescope (JWST) near- and mid-infrared photometry and spectroscopy to create spectral energy distributions of SN 2023ixf at +374 and +620 days post-explosion, covering a wavelength range of ~0.1-30 $μ$m. The multi-band light curve …

A first look at rocky exoplanets with JWST
Laura Kreidberg, Kevin B. Stevenson
https://arxiv.org/abs/2507.00933 https://arxiv.org/pdf…

A first look at rocky exoplanets with JWST
Rocky exoplanet characterization has been a top priority for early James Webb Space Telescope (JWST) science operations. Several milestones have been achieved, including the most precise rocky planet transmission spectra measured to date, and the first detection of thermal emission for rocky worlds below 800 Kelvin. Despite these advances, no atmospheres have been definitively detected. Several transmission spectra show tentative evidence for molecular absorption features, but these hints are m…

A Pristine Star-Forming Complex at z=4.19
E. Vanzella, M. Messa, A. Zanella, A. Bolamperti, M. Castellano, F. Loiacono, P. Bergamini, G. Roberts-Borsani, A. Adamo, A. Fontana, T. Treu, F. Calura, C. Grillo, M. Lombardi, P. Rosati, R. Gilli, M. Meneghetti
https://arxiv.org/abs/2509.07073

A Pristine Star-Forming Complex at z=4.19
We report the discovery of a faint (M_1700 ~ -12.2), oxygen-deficient strongly-lensed ionizing source -- dubbed LAP2 (Lensed And Pristine 2) -- at a spectroscopic redshift of z=4.19. LAP2 appears to be isolated and lies very close to the caustic produced by the lensing galaxy cluster Abell 2744. It was observed with the James Webb Space Telescope (JWST) NIRSpec MSA in prism mode as part of the UNCOVER program. The NIRSpec spectrum reveals prominent Lya emission (7.1 sigma), clear Ha emission (6…

JWST Imaging of the Closest Globular Clusters -- VI. The Lowest-Mass Objects in M 4 and the Galactic Bulge
L. R. Bedin (INAF-OAPD), R. Gerasimov (Univ. Notre Dame IN-USA), A. Calamida (STScI), M. Libralato (INAF-OAPD), M. Scalco (Bloomington Indiana Univ), D. Nardiello (Univ.PD), M. Griggio (STScI), D. Apai (UniAZ Tucson-USA, and), J. Anderson (STScI), A. Bellini (STScI), A. J. Burgasser (UC SanDiego-USA)

JWST Imaging of the Closest Globular Clusters -- VI. The Lowest-Mass Objects in M 4 and the Galactic Bulge
We present `James Webb Space Telescope' observations of M4 -- the closest globular cluster -- that probe the lower Main Sequence down to the hydrogen-burning limit. The unveiled stellar sequence reaches much fainter luminosities than previously possible, revealing a few extremely red objects that are consistent with brown dwarfs as cool as T_eff~1000K. However, the lack of a second JWST epoch presently prevents us from verifying the cluster membership of these objects. By cross-matching our dat…

Blowing Star Formation Away in AGN Hosts (BAH) -- IV. Serendipitous discovery of a $z\sim2.9$ star-forming galaxy lensed by the galactic bulge of CGCG\:012-070 using JWST NIRSpec
Rogemar A. Riffel, Carlos R. Melo-Carneiro, Gabriel Luan Souza-Oliveira, Rog\'erio Riffel, Cristina Furlanetto, Santiago Arriba, Marina Bianchin, Ana L. Chies-Santos, Jos\'e Henrique Costa-Souza, Mait\^e S. Z. de Mellos, Michele Perna, Thaisa Storchi-Bergmann, Nadia L. Zakamska

Blowing Star Formation Away in AGN Hosts (BAH) -- IV. Serendipitous discovery of a $z\sim2.9$ star-forming galaxy lensed by the galactic bulge of CGCG\:012-070 using JWST NIRSpec
We report the detection of a gravitationally lensed galaxy by the nearby spiral galaxy CGCG 012-070 ($z = 0.048$) using Integral Field Unit (IFU) observations with the Near-Infrared Spectrograph (NIRSpec) instrument on board the James Webb Space Telescope (JWST). The lensed galaxy is identified through the flux distributions of emission lines in the rest-frame optical, consistent with a source located at a redshift of $z\sim2.89$. The system is detected in [O III]$λ\lambda4959,5007$, H$β$, an…

Introducing the Phoebos simulation: galaxy properties at the dawn of galaxy formation
Floor van Donkelaar, Pedro R. Capelo, Lucio Mayer, Darren S. Reed, Thomas R. Quinn
https://arxiv.org/abs/2507.04927

Introducing the Phoebos simulation: galaxy properties at the dawn of galaxy formation
The James Webb Space Telescope (JWST) now allows us to observe galaxies at the end of cosmic dawn ($z \sim 10-15$) with unprecedented detail, revealing their morphologies, sizes, and internal structures. These observations offer crucial insights into the physical processes driving early galaxy formation. In this work, we introduce the Phoebos hydrodynamical cosmological simulation, a state-of-the-art 100 Mpc volume designed to study the formation and evolution of galaxies at the end of cosmic d…

New Insight from the James Webb Space Telescope on Variable Active Galactic Nuclei
Bangzheng Sun, Haojing Yan, Wei Leong Tee, Feige Wang
https://arxiv.org/abs/2508.14350 https:/…

New Insight from the James Webb Space Telescope on Variable Active Galactic Nuclei
Variability detected in galaxies is usually attributed to their active galactic nuclei (AGNs). While all AGNs are intrinsically variable, the classic AGN unification model predicts that type~2 AGNs rarely vary because their engines are obstructed by dust tori. Previous UV-to-near-IR variability studies largely support this expectation. Here, we present a variability study by James Webb Space Telescope (JWST) that reveals a more subtle picture. Using NIRCam imaging data from three surveys over $…

Sieging HELM's deep: PRIMA unveils the far-infrared properties of highly extincted low-mass galaxies
Laura Bisigello, Carlotta Gruppioni, Giulia Rodighiero, Giovanni Gandolfi, James M. S. Donnellan, Seb Oliver, Stephen M. Wilkins, L. Y. Aaron Yung
https://arxiv.org/abs/2509.01305

Sieging HELM's deep: PRIMA unveils the far-infrared properties of highly extincted low-mass galaxies
Although the majority of star-forming galaxies show a tight correlation between stellar mass and dust extinction, recent James Webb Space Telescope observations have revealed a peculiar population of Highly Extincted Low-Mass (HELM) galaxies, which could revolutionise our understanding of dust production mechanisms. To fully understand the dust content of these galaxies, which are a minority of the overall galaxy population, far-infrared observations over large areas are pivotal. In this paper,…

Silane-Methane Competition in Sub-Neptune Atmospheres as a Diagnostic of Metallicity and Magma Oceans
Kaustubh Hakim, Dan J. Bower, Fabian Seidler, Paolo A. Sossi
https://arxiv.org/abs/2508.19235

Silane-Methane Competition in Sub-Neptune Atmospheres as a Diagnostic of Metallicity and Magma Oceans
The James Webb Space Telescope is characterising the atmospheres of sub-Neptunes. The presence of magma oceans on sub-Neptunes is expected to strongly alter the chemistry of their envelopes (100 bar-100 kbar) and atmospheres (1 mbar-100 bar). At the magma ocean-envelope boundary (MEB, >10 kbar), gas properties deviate from ideality, yet the effects of real gas behaviour on chemical equilibria remain underexplored. Here, we compute equilibrium between magma-gas and gas-gas reactions using real g…

Resolving Emission from Small Dust Grains in the Blue Compact Dwarf II Zw 40 with JWST
Thomas S. -Y. Lai, Sara Duval, J. D. T. Smith, Lee Armus, Adolf N. Witt, Karin Sandstrom, Elizabeth Tarantino, Shunsuke Baba, Alberto Bolatto, Grant P. Donnelly, Brandon S. Hensley, Masatoshi Imanishi, Laura Lenkic, Sean Linden, Takao Nakagawa, Henrik W. W. Spoon, Aditya Togi, Cory M. Whitcomb

Resolving Emission from Small Dust Grains in the Blue Compact Dwarf II Zw 40 with JWST
We present James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) and Mid-infrared Instrument (MIRI) integral-field spectroscopy of the nearby blue compact dwarf II Zw 40, which has a low metallicity of 25% of solar. Leveraging the high spatial/spectral resolution and wavelength coverage of JWST/NIRSpec, we present robust detections of the 3.3 um polycyclic aromatic hydrocarbon (PAH) emission on 20 pc scales. The strength of the Pf delta emission relative to the 3.3 PAH feature …

JWST detection of a carbon dioxide dominated gas coma surrounding interstellar object 3I/ATLAS
Martin A. Cordiner, Nathaniel X. Roth, Michael S. P. Kelley, Dennis Bodewits, Steven B. Charnley, Maria N. Drozdovskaya, Davide Farnocchia, Marco Micheli, Stefanie N. Milam, Cyrielle Opitom, Megan E. Schwamb, Cristina A. Thomas
https://arxiv.org/…

JWST detection of a carbon dioxide dominated gas coma surrounding interstellar object 3I/ATLAS
3I/ATLAS is the third confirmed interstellar object to visit our Solar System, and only the second to display a clear coma. Infrared spectroscopy with the James Webb Space Telescope (JWST) provides the opportunity to measure its coma composition and determine the primary activity drivers. We report the first results from our JWST NIRSpec campaign for 3I/ATLAS, at an inbound heliocentric distance of $r_H=3.32$ au. The spectral images (spanning 0.6-5.3 $μ$m) reveal a CO2 dominated coma, with enh…

LAP1-B is the First Observed System Consistent with Theoretical Predictions for Population III Stars
Eli Visbal, Ryan Hazlett, Greg L. Bryan
https://arxiv.org/abs/2508.03842 htt…

LAP1-B is the First Observed System Consistent with Theoretical Predictions for Population III Stars
Recently, Nakajima et al. (2025) presented James Webb Space Telescope observations of the $z=6.6$ Population III (Pop III) candidate LAP1-B, which is gravitationally lensed by galaxy cluster MACS J0416. We argue that this is the first object to agree with three key theoretical predictions for Pop III stars: (1) formation in extremely low-metallicity halos with virial temperatures ranging from $T_{\rm vir}\sim 10^3-10^4~{\rm K}$, (2) a top-heavy initial mass function, and (3) formation of low-ma…

Investigating the Influence of Asymmetric Errors on Retrievals of Exoplanet Transmission Spectra
Jack J. Davey, Kai Hou Yip, Quentin Changeat, Ingo P. Waldmann
https://arxiv.org/abs/2507.19223

Investigating the Influence of Asymmetric Errors on Retrievals of Exoplanet Transmission Spectra
In studies of exoplanet atmospheres using transmission spectroscopy, Bayesian retrievals are the most popular form of analysis. In these procedures it is common to adopt a Gaussian likelihood. However, this implicitly assumes that the upper and lower error bars on the spectral points are equal. With recent observations from the James Webb Space Telescope (JWST) offering higher quality of data, it is worth revisiting this assumption to understand the impact that an asymmetry between the error ba…

A fast machine learning tool to predict the composition of astronomical ices from infrared absorption spectra
Andr\'es Meg\'ias, Izaskun Jim\'enez-Serra, Fran\c{c}ois Dulieu, Julie Vitorino, Bel\'en Mat\'e, David Ciudad, Will R. M. Rocha, Marcos Mart\'inez Jim\'enez, Jacobo Aguirre
https://arxiv.org/abs/2509.043…

A fast machine learning tool to predict the composition of astronomical ices from infrared absorption spectra
Current observations taken by James Webb Space Telescope (JWST) allow us to observe the absorption features of icy mantles that cover interstellar dust grains, which are mainly composed of $\mathrm{H_2O}$, $\mathrm{CO}$, and $\mathrm{CO_2}$, along with other minor species. Thanks to its sensitivity and spectral resolution, JWST has the potential to observe ice features towards hundreds of sources at different stages along the process of star formation. However, identifying the spectral features…

Little Red Dots Are Nurseries of Massive Black Holes
Fabio Pacucci, Lars Hernquist, Michiko Fujii
https://arxiv.org/abs/2509.02664 https://arxiv.org/pdf/25…

Little Red Dots Are Nurseries of Massive Black Holes
The James Webb Space Telescope (JWST) has revealed a previously unknown population of compact, red galaxies at $z \sim 5$, known as "Little Red Dots" (LRDs). With effective radii of $\sim 100$ pc and stellar masses of $10^9-10^{11} \, \rm M_\odot$, a purely stellar interpretation implies extreme central densities, $ρ_\star\sim10^4-10^5 \, \rm M_\odot \, pc^{-3}$ and in some cases up to $\sim 10^9 \, \rm M_\odot \, pc^{-3}$, far exceeding those of globular clusters. At such densities, the dynam…

Osiris revisited: Confirming a solar metallicity and low C/O in HD 209458b
N. Bachmann, L. Kreidberg, P. Molli\`ere, D. Deming, S. -M. Tsai
https://arxiv.org/abs/2506.16232

Osiris revisited: Confirming a solar metallicity and low C/O in HD 209458b
HD 209458b is the prototypical hot Jupiter and one of the best targets available for precise atmosphere characterisation. Now that spectra from both Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) are available, we can reveal the atmospheric properties in unprecedented detail. In this study, we perform a new data reduction and analysis of the original HST/WFC3 spectrum, accounting for the wavelength dependence of the instrument systematics that was not considered in previous …

How similar are narrow-line Seyfert 1 galaxies and high-z type 1 AGN?
M. Berton, E. J\"arvel\"a, A. Tortosa, C. Mazzucchelli
https://arxiv.org/abs/2509.03576 https://

How similar are narrow-line Seyfert 1 galaxies and high-z type 1 AGN?
The recent observations of highly accreting supermassive black holes (SMBH) at very high redshift ($>$4) with the James Webb Space Telescope (JWST) allowed us to shed light for the very first time on the early evolutionary phases of active galactic nuclei (AGN). Perhaps unsurprisingly, several of the physical properties observed in these new objects, including those known as little red dots (LRDs), are closely reminiscent of the low-mass and high-Eddington AGN in the local Universe, and in part…

Prospects of detecting rotational flatness of exoplanets from space-based photometry
Sz. K\'alm\'an, Sz. Csizmadia, L. M. Bernab\'o, R. Szab\'o, Gy. M. Szab\'o
https://arxiv.org/abs/2507.15359

Prospects of detecting rotational flatness of exoplanets from space-based photometry
In the era of photometry with space-based telescopes, such as CHEOPS (CHaracterizing ExOPlanets Satellite), JWST (James Webb Space Telescope), PLATO (PLAnetary Transits and Oscillations of stars), and ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey), the road has opened for detecting subtle distortions in exoplanet transit light curves -- resulting from their non-spherical shape. We investigate the prospects of retrieval of rotational flatness (oblateness) of exoplanets at var…

No Luminous Little Red Dots: A Sharp Cutoff in Their Luminosity Function
Yilun Ma, Jenny E. Greene, Marta Volonteri, Andy D. Goulding, David J. Setton, Marianna Annunziatella, Eiichi Egami, Xiaohui Fan, Vasily Kokorev, Ivo Labbe, Xiaojing Lin, Danilo Marchesini, Jorryt Matthee, Themiya Nanayakkara, Luke Robbins, Anna Sajina, Marcin Sawicki
https://

No Luminous Little Red Dots: A Sharp Cutoff in Their Luminosity Function
One of the most surprising results of early James Webb Space Telescope (JWST) observations is the discovery of an abundance of red, compact, broad-line objects dubbed "little red dots" (LRDs) at $z>4$. Their spatial density ($\sim10^{-4}$-$10^{-5}\,\mathrm{cMpc^{-3}}$) is 100 times more abundant than UV-selected quasars at those redshift if one extrapolates the quasar luminosity function (QLF) down to the LRD regime. However, whether LRDs dominate black hole accretion at quasar-like luminositie…

XUE 10. The CO$_2$-rich terrestrial planet-forming region of an externally irradiated Herbig disk
Jenny Frediani, Arjan Bik, Mar\'ia Claudia Ram\'irez-Tannus, Rens Waters, Konstantin V. Getman, Eric D. Feigelson, Bayron Portilla-Revelo, Beno\^it Tabone, Thomas J. Haworth, Andrew Winter, Thomas Henning, Giulia Perotti, Alexis Brandeker, Germ\'an Chaparro, Pablo Cuartas-Restrepo, Sebasti\'an Hern\'andez, Michael A. Kuhn, Thomas Preibisch, Veronica Roccatagliata, Sierk…

XUE 10. The CO$_2$-rich terrestrial planet-forming region of an externally irradiated Herbig disk
We investigate the James Webb Space Telescope (JWST) MIRI MRS gas molecular content of an externally irradiated Herbig disk, the F-type XUE 10 source, in the context of the eXtreme UV Environments (XUE) program. XUE 10 belongs to the massive star cluster NGC 6357 (1.69 kpc), where it is exposed to an external far-ultraviolet (FUV) radiation $\approx$ 10$^3$ times stronger than in the Solar neighborhood. We modeled the molecular features in the mid-infrared spectrum with Local Thermodynamic Equi…

Understanding the Evolution of Black Hole Accretion and Dust out to z=4 with a Deep Imaging Extragalactic Survey with PRIMA
Andreas L. Faisst, Chian-Chou Chen, Laure Ciesla, Carlotta Gruppioni
https://arxiv.org/abs/2509.01674

Understanding the Evolution of Black Hole Accretion and Dust out to z=4 with a Deep Imaging Extragalactic Survey with PRIMA
The cosmic evolution of obscured star formation, dust properties and production mechanisms, and the prevalence of dust-obscured AGN out to high redshifts are currently some of the hot topics in astrophysics. While much progress has been made in the early days with Spitzer and Herschel, these facilities have not reached the necessary depths to observe the mid-IR light of high-redshift (z > 3) galaxies. Recently, the James Webb Space Telescope (JWST) has filled in the blue side of the rest-frame …

High-redshift Galaxies from JWST Observations in More Realistic Dark Matter Halo Models
Saeed Fakhry, Reyhaneh Vojoudi Salmani, Javad T. Firouzjaee
https://arxiv.org/abs/2507.23742

High-redshift Galaxies from JWST Observations in More Realistic Dark Matter Halo Models
The James Webb Space Telescope (JWST) has unveiled unexpectedly massive galaxy candidates at high redshifts, challenging standard $Λ$CDM cosmological predictions. In this work, we study the predictions of more realistic dark matter halo models combined with modified matter power spectra for interpreting JWST observations of high-redshift galaxies. We employ three halo mass functions: the conventional Sheth-Tormen (ST) model and two physically motivated alternatives introduced by Del Popolo (DP…

Revealing Io's Surface using JWST-NIRISS Aperture Masking Interferometry and Neural Network Deconvolution
J. Sanchez-Bermudez, I. dePater, A. Conrad, A. Sivaramakrishnan, E. Molter, D. Thatte, R. Cooper, K. deKleer, L. Roth
https://arxiv.org/abs/2508.14720

Revealing Io's Surface using JWST-NIRISS Aperture Masking Interferometry and Neural Network Deconvolution
Io is one of Jupiter's largest moons and the most volcanically active body in the Solar System. Its very active surface has hot spots produced by volcanic eruptions popping up at seemingly random locations and times. Characterizing the complex surface of Io requires the highest angular resolution available. This work presents the analysis of Aperture Masking Interferometric observations (at 4.3 um) of Io taken with the Near-Infrared Imager and Slitless Spectrograph instrument on the James Webb …

Formation of over-massive black holes in high-redshift disk galaxies via globular cluster accretion
Hidenobu Yajima
https://arxiv.org/abs/2507.22863 https://

Formation of over-massive black holes in high-redshift disk galaxies via globular cluster accretion
Recent observations with the James Webb Space Telescope (JWST) have suggested the existence of over-massive black holes (OMBHs) in high-redshift galaxies. In this paper, we propose a new mechanism for the formation of OMBHs, based on the accretion of globular clusters (GCs) in compact disk galaxies. We derive the conditions under which OMBHs can form, focusing on key parameters such as halo mass, redshift, and halo spin parameter. Our results show that at redshift $z = 10$, a halo with mass $10…

SHELLQs-JWST perspective on the intrinsic mass relation between supermassive black holes and their host galaxies at z > 6
John Silverman, Junyao Li, Xuheng Ding, Masafusa Onoue, Michael Strauss, Yoshiki Matsuoka, Takuma Izumi, Knud Jahnke, Tommaso Treu, Marta Volonteri, Camryn Phillips, Irham Andika, Kentaro Aoki, Junya Arita, Shunsuke Baba, Sarah Bosman, Anna-Christina Eilers, Xiaohui Fan, Seiji Fujimoto, Melanie Habouzit, Zoltan Haiman, Masatoshi Imanishi, Kohei Inayoshi, Kazushi …

SHELLQs-JWST perspective on the intrinsic mass relation between supermassive black holes and their host galaxies at z > 6
The relation between the masses of supermassive black holes (SMBHs) and their host galaxies encodes information on their mode of growth, especially at the earliest epochs. The James Webb Space Telescope (JWST) has opened such investigations by detecting the host galaxies of AGN and more luminous quasars within the first billion years of the universe (z > 6). Here, we evaluate the relation between the mass of SMBHs and the total stellar mass of their host galaxies using a sample of nine quasars …

MINERVA: A NIRCam Medium Band and MIRI Imaging Survey to Unlock the Hidden Gems of the Distant Universe
Adam Muzzin, Katherine A. Suess, Danilo Marchesini, Luke Robbins, Chris J. Willott, Stacey Alberts, Jacqueline Antwi-Danso, Yoshihisa Asada, Gabriel Brammer, Sam E. Cutler, Kartheik G. Iyer, Ivo Labbe, Nicholas S. Martis, Tim B. Miller, Ikki Mitsuhashi, Alexandra Pope, Anna Sajina, Ghassan T. E. Sarrouh, Monu Sharma, Mauro Stefanon, Katherine E. Whitaker, Roberto Abraham, Hakim Atek,…

MINERVA: A NIRCam Medium Band and MIRI Imaging Survey to Unlock the Hidden Gems of the Distant Universe
We present an overview of the MINERVA survey, a 259.8 hour (prime) and 127 hour (parallel) Cycle 4 treasury program on the James Webb Space Telescope (JWST). MINERVA is obtaining 8 filter NIRCam medium band imaging (F140M, F162M, F182M, F210M, F250M, F300M, F360M, F460M) and 2 filter MIRI imaging (F1280W, F1500W) in four of the five CANDELS Extragalactic fields: UDS, COSMOS, AEGIS and GOODS-N. These fields were previously observed in Cycle 1 with 7 - 9 NIRCam filters by the PRIMER, CEERS and JA…

A Joint JWST and HST View of Omega Centauri: Multiple Stellar Populations and Their Kinematics
T. Ziliotto, A. P. Milone, G. Cordoni, A. F. Marino, M. V. Legnardi, E. Dondoglio, E. Bortolan, F. Muratore
https://arxiv.org/abs/2506.21187

A Joint JWST and HST View of Omega Centauri: Multiple Stellar Populations and Their Kinematics
We combine F115W and F277W images collected with the Near Infrared Camera of the James Webb Space Telescope (JWST) with multi-band, multi-epoch Hubble Space Telescope (HST) observations of Omega Centauri to investigate its multiple stellar populations and internal kinematics. Our study focuses on a region spanning $\sim$0.9 to $\sim$2.3 half-light radii from the cluster center, largely unexplored by HST and JWST. Using chromosome maps, we identify the principal populations along the upper main …

The Importance of the Population III Initial Mass Function in Determining the Characteristics of the Earliest Galaxies
Richard Sarmento, Evan Scannapieco
https://arxiv.org/abs/2506.20767

The Importance of the Population III Initial Mass Function in Determining the Characteristics of the Earliest Galaxies
We use large-scale cosmological simulations to study the prospect of observing Population III (Pop III) bright galaxies with the James Webb Space Telescope (JWST). To quantify the impact of radiative transfer (RT), we compare a simulation that includes moment-based RT with one in which RT is handled approximately. Both simulations include a subgrid model of turbulent mixing, which is essential in tracking the formation of Pop III stars. We find that RT has a minor impact on our results and that…

Signatures of BH seeding on the $\mathrm{M_{\displaystyle \bullet}}-\sigma$ relation: Predictions from the BRAHMA simulations
Jonathan Kho, Aklant K. Bhowmick, Paul Torrey, Alex M. Garcia, Niusha Ahvazi, Laura Blecha, Mark Vogelsberger
https://arxiv.org/abs/2506.17476

Signatures of BH seeding on the $\mathrm{M_{\displaystyle \bullet}}-σ$ relation: Predictions from the BRAHMA simulations
The James Webb Space Telescope (JWST) has identified a large population of supermassive ($10^6$-$10^8~\mathrm{M}_\odot$) black holes (BHs) in the early universe ($z \sim 4$-$7$). Current measurements suggest that many of these BHs exhibit higher BH-to-stellar mass ratios than local populations, opening a new window into the earliest stages of BH-galaxy coevolution and offering the potential to place tight constraints on BH seeding and growth in the early universe. In this work, we use the BRAHM…

Balmer Decrement and IRX Break in Tracing Dust Attenuation at Scales of Individual Star-forming Regions in NGC 628
Man Qiao, Mingfeng Liu, Zongfei Lyu, Shuang Liu, Chao Yang, Dong Dong Shi, Fangxia An, Zhizheng Pan, Wenhao Liu, Binyang Liu, Run Wen, Yu Heng Zhang, Xian Zhong Zheng
https://arxiv.org/abs/2506.21026

Balmer Decrement and IRX Break in Tracing Dust Attenuation at Scales of Individual Star-forming Regions in NGC 628
We investigate the relationships between infrared excess (IRX=$L_{\rm IR}/L_{\rm UV}$) and Balmer decrement (${\rm H}α/{\rm H}β$) as indicators of dust attenuation for 609 ${\rm {H\,{\small II}}}$ regions at scales of $\sim 50-200$ pc in NGC 628, utilizing data from AstroSat, James Webb Space Telescope (JWST) and Multi Unit Spectroscopic Explorer (MUSE). Our findings indicate that about three fifths of the sample ${\rm {H\,{\small II}}}$ regions reside within the regime occupied by local star…

On the Variability Features of Active Galactic Nuclei in Little Red Dots
Shuying Zhou, Mouyuan Sun, Zijian Zhang, Jie Chen, Luis C. Ho
https://arxiv.org/abs/2508.16795 https://

On the Variability Features of Active Galactic Nuclei in Little Red Dots
The high-redshift ($z>4$) compact sources with ``V-shaped" spectral energy distributions (SEDs), known as Little Red Dots (LRDs), are discovered by the James Webb Space Telescope and provide valuable clues to the physics of active galactic nuclei (AGNs) in the early universe. The nature of LRDs is controversial. Recently, several studies have investigated LRDs through variability, a characteristic feature of AGNs. These studies explore LRD variability by extrapolating empirical relationships fr…

Stellar Mass Assembly History of Massive Quiescent Galaxies since $z\sim4$: Insights from Spatially Resolved SED Fitting with JWST Data
Novan Saputra Haryana, Masayuki Akiyama, Abdurro'uf, Hesti Retno Tri Wulandari, Juan Pablo Alfonzo, Kianhong Lee, Naoki Matsumoto, Ryo Albert Sutanto, Muhammad Nur Ihsan Effendi, Itsna Khoirul Fitriana, Ibnu Nurul Huda, Anton Timur Jaelani, Sultan Hadi Kusuma, Lucky Puspitarini, Dian Puspita Triani

Stellar Mass Assembly History of Massive Quiescent Galaxies since $z\sim4$: Insights from Spatially Resolved SED Fitting with JWST Data
Massive quiescent galaxies at high redshift show significantly more compact morphology than their local counterparts. To examine their internal structure across a wide redshift range and investigate potential redshift dependence, we performed spatially resolved SED fitting using pixedfit software on massive $(\log(M_*/M_\odot)\sim11)$ quiescent galaxies at $0

Glimmers in the Cosmic Dawn. III. On the Photometrically Determined Black Hole Mass to Stellar Mass Relation Across Cosmic Time
Alice R. Young, Matthew J. Hayes, Alberto Saldana-Lopez, Axel Runnholm, Vieri Cammelli, Jonathan C. Tan, Richard S. Ellis, Benjamin W. Keller, Jens Melinder, Jasbir Singh
https://arxiv.org/abs/2508.15905

Glimmers in the Cosmic Dawn. III. On the Photometrically Determined Black Hole Mass to Stellar Mass Relation Across Cosmic Time
We present the results from performing spectral energy distribution (SED) fitting on 121 variable active galactic nuclei (AGN) candidates in the Hubble Ultra Deep Field (HUDF) using photometry from both the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST) covering $0.2 - 4.8$ microns. We designed a bespoke SED fitting code which decomposes the total SED into its stellar and AGN contributions. Our SED fitting retrieves a significant contribution to the total SED from an AGN…

Little Red Dots as Direct-collapse Black Hole Nurseries
Elia Cenci, Melanie Habouzit
https://arxiv.org/abs/2508.14897 https://arxiv.org/pdf/2508.14897

Little Red Dots as Direct-collapse Black Hole Nurseries
The James Webb Space Telescope recently uncovered a population of massive black holes (BHs) in the first billion years after the Big Bang. Among these high-redshift BH candidates, observations have identified a class of active galactic nuclei candidates, dubbed Little Red Dots (LRDs), with extraordinarily compact gas reservoirs and peculiar spectral features. LRDs clearly emerge at redshift z<8 and their abundance declines by z<5. Recent theoretical studies have explored the link between LRDs a…

Little Red Dots and their Progenitors from Direct Collapse Black Holes
Junehyoung Jeon, Boyuan Liu, Volker Bromm, Seiji Fujimoto, Anthony J. Taylor, Vasily Kokorev, Rebecca L. Larson, John Chisholm, Steven L. Finkelstein, Dale D. Kocevski
https://arxiv.org/abs/2508.14155

Little Red Dots and their Progenitors from Direct Collapse Black Holes
The James Webb Space Telescope (JWST) has discovered a new population of objects, the Little Red Dots (LRDs), characterized by V-shaped spectra indicative of strong breaks around the Balmer limit and compact morphology that gave them their name. A popular explanation is that they are a sub-population of active galactic nuclei/supermassive black holes (AGN/SMBHs) predominantly found in the high-redshift Universe ($z\gtrsim3$). Similarly, direct collapse black holes (DCBHs), theorized to form fro…

Efficient black hole seed formation in low metallicity and dense stellar clusters with implications for JWST sources
M. C. Vergara, A. Askar, F. Flammini Dotti, D. R. G. Schleicher, A. Escala, R. Spurzem, M. Giersz, J. Hurley, M. Arca Sedda, N. Neumayer
https://arxiv.org/abs/2508.14260

Efficient black hole seed formation in low metallicity and dense stellar clusters with implications for JWST sources
Recent observations with the James Webb Space Telescope (JWST) reveal young massive clusters (YMCs) as key building blocks of early galaxies. They are not only important constituents of galaxies, but also potential birthplaces of very massive stars (VMSs) and black hole (BH) seeds. We explore stellar dynamics in extremely dense clusters with initial half-mass densities of $ρ_h \gtrsim 10^8M_\odot{\rm pc}^{-3}$ at very low metallicity, comparable to some of the densest clusters seen by JWST. Us…

Overview of complex organic molecule observations in protostellar systems
P. Nazari
https://arxiv.org/abs/2508.15771 https://arxiv.org/pdf/2508.15771

Overview of complex organic molecule observations in protostellar systems
Complex organic molecules (COMs) have been detected abundantly at various stages of star formation, particularly in the warm protostellar phase. The progress in gas-phase measurements has been accelerated by the advent of the Atacama Large Millimeter/submillimeter Array and in ice measurements by the James Webb Space Telescope. Particularly, the community has moved from single-source studies of COMs to statistical analyses because of these powerful instruments. In this article, I review surveys…

The Fraction of Clumpy Galaxies in JWST Surveys over $2<z<12$
Alexander de la Vega, Bahram Mobasher, Faezeh Manesh, Niloofar Sharei, Nima Chartab, Zahra Sattari
https://arxiv.org/abs/2508.14972

The Fraction of Clumpy Galaxies in JWST Surveys over $2
High-redshift galaxies exhibit compact regions of intense star formation, known as ``clumps,'' which are conspicuous in the rest-frame ultraviolet. Studying them can shed light on how they form and evolve and inform theoretical models of galaxy evolution. We examine the evolution of clumpy galaxies with redshift and stellar mass over $2