Tootfinder

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�…

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…

Photometric Mapping of Carbonaceous/Siliceous Dust and Water Ice in the ISM with JWST: Applications to the Dense Sightlines
Burcu G\"unay, Karl D. Gordon, Joshua E. G. Peek, Marjorie Decleir, Dries Van De Putte, Kirill Tchernyshyov, Michael G. Burton
https://arxiv.org/abs/2507.17550

Photometric Mapping of Carbonaceous/Siliceous Dust and Water Ice in the ISM with JWST: Applications to the Dense Sightlines
We introduce a new photometric mapping method for the James Webb Space Telescope (JWST) to measure the spatial distribution of carbonaceous dust, siliceous dust and water ice by using absorption features arising from the grains in the dense interstellar medium (ISM). Employing NIRCam and MIRI imaging filters, low-resolution spectroscopic data can be obtained to measure the optical depths of the 3.0-$μ$m water ice -OH feature, the 3.4-$μ$m aliphatic hydrocarbon -CH feature, and the 10-$μ$m si…

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.

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 …

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…

🔍 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…

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…

Nature of High Equivalent Width Emitters in the Epoch of Reionization Revealed by JWST Medium-band Imaging
Kazuki Daikuhara, Takahiro Morishita, Tadayuki Kodama, Ranga-Ram Chary, Masayuki Akiyama, Jose. M. P\'erez-Mart\'inez
https://arxiv.org/abs/2507.13456

Nature of High Equivalent Width Emitters in the Epoch of Reionization Revealed by JWST Medium-band Imaging
Extreme emission line galaxies (EELGs) at high redshifts are considered key contributors to cosmic reionization at $z>6$ due to their higher ionization efficiencies. We have identified 119 H$β$ + [OIII] emitters at $z\sim7$ selected by a flux excess in the medium-band filter F410M in the public James Webb Space Telescope Cycle-1 fields. Our emitters exhibit a wide range in rest-frame H$β$ + [OIII] equivalent width (EWs), 420 $<$ EW$_{0}$/Å $<$ 6850 (with the median value of $\sim1700$ Å). A…

Evidence of haze control of Pluto’s atmospheric heat balance from JWST/MIRI thermal light curves: #Pluto

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…

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 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 …

This https://arxiv.org/abs/2504.14009 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Large Cold Dust Reservoir Revealed in Transitional SN Ib 2014C by James Webb Space Telescope Mid-Infrared Spectroscopy
Supernova (SN) 2014C is a rare transitional event that exploded as a hydrogen-poor, helium-rich Type Ib SN and subsequently interacted with a hydrogen-rich circumstellar medium (CSM) a few months post-explosion. This unique interacting object provides an opportunity to probe the mass-loss history of a stripped-envelope SN progenitor. Using the James Webb Space Telescope (JWST), we observed SN 2014C with the Mid-Infrared Instrument Medium Resolution Spectrometer at 3477 days post-explosion (rest…

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…

Insights from a 30-Year international Partnership on Astronomical Archives
David R. Rodriguez, Maria Arevalo, Patrick Dowler, Javier Espinosa, Brian McLean, Chris Willott
https://arxiv.org/abs/2506.11888

Insights from a 30-Year international Partnership on Astronomical Archives
In an era where astronomical data is expanding at an unprecedented rate, the importance of data sharing and accessibility among astronomy archives cannot be overstated. Since the 1990s, an international partnership between the Space Telescope Science Institute (STScI), the European Space Astronomy Centre (ESAC), and the Canadian Astronomy Data Centre (CADC) has been focused on this endeavor, facilitating the exchange of data from the Hubble and James Webb Space Telescopes. We will present how…

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…

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 Coronagraphic Images of 14 Her c: a Cold Giant Planet in a Dynamically Hot, Multi-planet System
Daniella C. Bardalez Gagliuffi, William O. Balmer, Laurent Pueyo, Timothy D. Brandt, Mark R. Giovinazzi, Sarah Millholland, Brennen Black, Tiger Lu, Malena Rice, James Mang, Caroline Morley, Brianna Lacy, Julien Girard, Elisabeth Matthews, Aarynn Carter, Brendan P. Bowler, Jacqueline K. Faherty, Clemence Fontanive, Emily Rickman

JWST Coronagraphic Images of 14 Her c: a Cold Giant Planet in a Dynamically Hot, Multi-planet System
Most observed multi-planet systems are coplanar, in a dynamically "cold" configuration of concentric orbits like our own Solar System. With the James Webb Space Telescope (JWST) we have detected 14 Her c, the first mature and cold exoplanet directly imaged in a dynamically "hot", multi-planet system. With large eccentricities and a nonzero mutual inclination, the present-day architecture of this system points to a turbulent past and ongoing angular momentum exchange between the planetary orbits…

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…

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…

Gone with the Wind: JWST-MIRI Unveils a Strong Outflow from the Quiescent Stellar-Mass Black Hole A0620-00
Zihao Zuo, Gabriele Cugno, Joseph Michail, Elena Gallo, David M. Russell, Richard M. Plotkin, Fan Zou, M. Cristina Baglio, Piergiorgio Casella, Fraser J. Cowie, Rob Fender, Poshak Gandhi, Sera Markoff, Federico Vincentelli, Fraser Lewis, Jon M. Miller, James C. A. Miller-Jones, Alexandra Veledina

Gone with the Wind: JWST-MIRI Unveils a Strong Outflow from the Quiescent Stellar-Mass Black Hole A0620-00
We present new observations of the black hole X-ray binary A0620-00 using the Mid-Infrared Instrument on the James Webb Space Telescope, during a state where the X-ray luminosity is 9 orders of magnitude below Eddington, and coordinated with radio, near-infrared and optical observations. The goal is to understand the nature of the excess mid-infrared (MIR) emission originally detected by Spitzer red-ward of 8 $μ$m. The stellar-subtracted MIR spectrum is well-modeled by a power law with a spect…

The Diversity of Exoplanetary Environments and the Search for Signs of Life Beyond Earth
Sara Seager, Janusz J. Petkowski, William Bains
https://arxiv.org/abs/2506.11690

The Diversity of Exoplanetary Environments and the Search for Signs of Life Beyond Earth
Thousands of exoplanets orbit nearby stars, showcasing a remarkable diversity in mass, size, and orbits. With the James Webb Space Telescope now operational, we are observing exoplanet atmospheres and aiming to reach down to small, habitable-zone exoplanets in search of signs of habitability and possibly even biosignature gases. Given the scarcity of targets, it is imperative to embrace the known diversity and consider the range of exoplanets that might host life. We review how Earth life inter…

SPECULOOS: five years hunting terrestrial planets around ultra-cool dwarfs
Sebasti\'an Z\'u\~niga-Fern\'andez (Astrobiology Research Unit, Universit\'e de Li\`ege, Li\`ege, Belgium), Michael Gillon (Astrobiology Research Unit, Universit\'e de Li\`ege, Li\`ege, Belgium), SPECULOOS consortium
https://arxiv.org/…

SPECULOOS: five years hunting terrestrial planets around ultra-cool dwarfs
The SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) project aims to detect temperate terrestrial planets transiting nearby ultracool dwarfs, including late M-dwarf stars and brown dwarfs, which are well-suited for atmospheric characterization using the James Webb Space Telescope (JWST) and upcoming giant telescopes like the European Extremely Large Telescope (ELT). Led by the University of Liège, SPECULOOS is conducted in partnership with the University of Cambridge, the Un…

Limb-Darkening Coefficients for the 4-Term and Power-2 Laws for the JWST Space Mission, Adopting PHOENIX Spherical Models at High Resolution
A. Claret (IAA), P. H. Hauschildt (Hamburger Sternwarte), G. Torres (CfA)
https://arxiv.org/abs/2506.07265

Limb-Darkening Coefficients for the 4-Term and Power-2 Laws for the JWST Space Mission, Adopting PHOENIX Spherical Models at High Resolution
Modeling observations of transiting exoplanets or close binary systems by comparing the observations with theoretical light curves requires precise knowledge of the distribution of specific intensities across the stellar disk. We aim to facilitate this type of research by providing extensive tabulations of limb-darkening coefficients for 11 frequently used near- and mid-infrared passbands on the NIRCam, NIRISS, and NIRSpec instruments installed on board the James Webb Space Telescope. The calcu…

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 (…

An Ultra-Faint, Chemically Primitive Galaxy Forming at the Epoch of Reionization
Kimihiko Nakajima, Masami Ouchi, Yuichi Harikane, Eros Vanzella, Yoshiaki Ono, Yuki Isobe, Moka Nishigaki, Takuji Tsujimoto, Fumitaka Nakamura, Yi Xu, Hiroya Umeda, Yechi Zhang
https://arxiv.org/abs/2506.11846…

An Ultra-Faint, Chemically Primitive Galaxy Forming at the Epoch of Reionization
The formation of the first stars and galaxies marked the onset of cosmic structure and chemical enrichment, yet direct observations of such primordial systems remain elusive. Here we present James Webb Space Telescope spectroscopic observations of LAP1-B, an ultra-faint galaxy at redshift z_{spec}=6.625 +/-0.001, corresponding to a cosmic age of 800 million years after the Big Bang, strongly magnified by gravitational lensing. LAP1-B exhibits a gas-phase oxygen abundance of (4.2 +/- 1.8) x 10^{…

This https://arxiv.org/abs/2506.03023 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

TDCOSMO 2025: Cosmological constraints from strong lensing time delays
We present cosmological constraints from 8 strongly lensed quasars (hereafter, the TDCOSMO-2025 sample). Building on previous work, our analysis incorporated new deflector stellar velocity dispersions measured from spectra obtained with the James Webb Space Telescope (JWST), the Keck Telescopes, and the Very Large Telescope (VLT), utilizing improved methods. We used integrated JWST stellar kinematics for 5 lenses, VLT-MUSE for 2, and resolved kinematics from Keck and JWST for RX J1131-1231. We …

TDCOSMO 2025: Cosmological constraints from strong lensing time delays
Simon Birrer, Elizabeth J. Buckley-Geer, Michele Cappellari, Frederic Courbin, Frederic Dux, Christopher D. Fassnacht, Joshua A. Frieman, Aymeric Galan, Daniel Gilman, Xiang-Yu Huang, Shawn Knabel, Danial Langeroodi, Huan Lin, Martin Millon, Takahiro Morishita, Veronica Motta, Pritom Mozumdar, Eric Paic, Anowar J. Shajib, William Sheu, Dominique Sluse, Alessandro Sonnenfeld, Chiara Spiniello, Massimo Stiavelli, Sher…

TDCOSMO 2025: Cosmological constraints from strong lensing time delays
We present cosmological constraints from 8 strongly lensed quasars (hereafter, the TDCOSMO-2025 sample). Building on previous work, our analysis incorporated new deflector stellar velocity dispersions measured from spectra obtained with the James Webb Space Telescope (JWST), the Keck Telescopes, and the Very Large Telescope (VLT), utilizing improved methods. We used integrated JWST stellar kinematics for 5 lenses, VLT-MUSE for 2, and resolved kinematics from Keck and JWST for RX J1131-1231. We …

The James Webb Space Telescope NIRSpec-PRISM Transmission Spectrum of the Super-Puff, Kepler-51d
Jessica E. Libby-Roberts, Aaron Bello-Arufe, Zachory K. Berta-Thompson, Caleb I. Ca\~nas, Yayaati Chachan, Renyu Hu, Yui Kawashima, Catriona Murray, Kazumasa Ohno, Armen Tokadjian, Suvrath Mahadevan, Kento Masuda, Leslie Hebb, Caroline Morley, Guangwei Fu, Peter Gao, Kevin B. Stevenson

The James Webb Space Telescope NIRSpec-PRISM Transmission Spectrum of the Super-Puff, Kepler-51d
Kepler-51 is a 500 Myr G dwarf hosting three "super-puffs" and one low-mass non-transiting planet. Kepler-51d, the coolest (T_eq ~ 350 K) transiting planet in this system, is also one of the lowest density super-puffs known to date (rho_p = 0.038 +/- 0.009 g/cm^3). With a planetary mass of Mp = 5.6 +/- 1.2 Earth masses and a radius of Rp = 9.32 +/- 0.18 Earth radii, the observed properties of this planet are not readily explained by most planet formation theories. Hypotheses explaining Kepler-5…

This https://arxiv.org/abs/2503.14703 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

The Emerging Black Hole Mass Function in the High-Redshift Universe
Observations with the James Webb Space Telescope (JWST) have identified an abundant population of supermassive black holes (SMBHs) already in place during the first few hundred million years of cosmic history. Most of them appear overmassive relative to the stellar mass in their host systems, challenging models of early black hole seeding and growth. Multiple pathways exist to explain their formation, including heavy seeds formed from direct collapse/supermassive stars or sustained super-Edding…

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.…

Lonely Little Red Dots: Challenges to the AGN-nature of little red dots through their clustering and spectral energy distributions
Mar\'ia de las Mercedes Carranza Escudero, Christopher J. Conselice, Nathan Adams, Thomas Harvey, Duncan Austin, Peter Behroozi, Leonardo Ferreira, Katherine Ormerod, Qiao Duan, James Trussler, Qiong Li, Lewi Westcott, Rogier A. Windhorst, Dan Coe, Seth H. Cohen, Cheng Cheng, Simon P. Driver, Brenda Frye, Lukas J. Furtak, Norman A. Grogin, Nimish P. Hat…

Lonely Little Red Dots: Challenges to the AGN-nature of little red dots through their clustering and spectral energy distributions
Observations with the James Webb Space Telescope (JWST) reveal a previously unseen population of compact red objects, known as ``little red dots`` (LRDs). We study a new photometrically selected sample of 124 LRDs in the redshift range $z$ $\sim$ 3 - 10 selected from NIRCam coverage of the CEERS, NEP-TDF, JADES and JEMS surveys. For JADES, the NEP-TDF and CEERS, we compare SED models with and without AGN components and analyse the impact of an AGN component on the goodness of fit using the Baye…

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 …

The properties of primordially-seeded black holes and their hosts in the first billion years: implications for JWST
Pratika Dayal, Roberto maiolino
https://arxiv.org/abs/2506.08116

The properties of primordially-seeded black holes and their hosts in the first billion years: implications for JWST
James Webb Space Telescope (JWST) observations have opened a tantalising new window onto possible black holes as early as redshifts of $z \sim 10.4$. These show a number of puzzling properties including unexpectedly massive black holes in place by $z \sim 10$ and inexplicably high black hole-to-stellar mass ratios of $M_{\rm BH}/M_*\geq 0.1$. These pose a serious challenge for "astrophysical" seeding and growth models that we aim to explain with ``cosmological" primordial black holes (PBHs) in …

Constraints on Quaoar's rings and atmosphere from JWST/NIRCam observations of a stellar occultation
Benjamin Proudfoot, Bryan Holler, Ko Arimatsu, Flavia Rommel, Cameron Collyer, Estela Fern\'andez-Valenzuela
https://arxiv.org/abs/2506.07898

Constraints on Quaoar's rings and atmosphere from JWST/NIRCam observations of a stellar occultation
Observations of stellar occultations have revealed that small bodies are capable of hosting ring systems. The trans-Neptunian object (TNO) Quaoar, is the host of an enigmatic ring system, with two rings located well-outside the Roche limit. To better understand these structures, we observed a stellar occultation by Quaoar and its rings using the James Webb Space Telescope's (JWST) NIRCam instrument. Our observations detect both known rings, although Q2R -- the inner known ring -- is not detecte…

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…

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…

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…

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…

JWST Insights into Narrow-line Little Red Dots
Zijian Zhang, Linhua Jiang, Weiyang Liu, Luis C. Ho, Kohei Inayoshi
https://arxiv.org/abs/2506.04350 https:/…

JWST Insights into Narrow-line Little Red Dots
James Webb Space Telescope (JWST) has revealed a population of red and compact objects with a unique V-shape SED at z >= 4 known as Little Red Dots (LRDs). Most of the LRDs with existing spectral observations exhibit broad Balmer lines and are thus likely to host active galactic nuclei (AGNs). Here we present a study of LRDs with no broad H-alpha component. Our sample consists of five LRDs at z~5 with H-alpha line widths of about 250 km/s. They are selected from 32 LRDs that have NIRSpec high- …

WASP-121b's transmission spectrum observed with JWST/NIRSpec G395H reveals thermal dissociation and SiO in the atmosphere
Cyril Gapp, Thomas M. Evans-Soma, Joanna K. Barstow, Joshua D. Lothringer, David K. Sing, Djemma Ruseva, Eva-Maria Ahrer, Jayesh M. Goyal, Duncan Christie, Laura Kreidberg, Nathan J. Mayne
https://arxiv.o…

WASP-121b's transmission spectrum observed with JWST/NIRSpec G395H reveals thermal dissociation and SiO in the atmosphere
WASP-121b has been established as a benchmark ultrahot Jupiter, serving as a laboratory for the atmospheric chemistry and dynamics of strongly irradiated extrasolar gas giants. Here, we present and analyze WASP-121b's transmission spectrum observed with NIRSpec G395H on board the James Webb Space Telescope and find evidence for the thermal dissociation of H$_2$O and H$_2$ on the planet's permanent dayside. Additionally, we detect SiO at a statistical significance of $5.2σ$ which is compatible …

This https://arxiv.org/abs/2506.04031 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Brightest Group Galaxies IV: Probing Size--Mass Relation and Morphological Quenching in COSMOS-Web from $z = 3.7$
We present a comprehensive study of the structural evolution of Brightest Group Galaxies (BGGs) from redshift $z \simeq 0.08$ to $z = 3.7$ using the \textit{James Webb Space Telescope}'s 255h COSMOS-Web program. This survey provides deep NIRCam imaging in four filters (F115W, F150W, F277W, F444W) across $\sim 0.54~\mathrm{deg}^2$ and MIRI coverage in $\sim 0.2~\mathrm{deg}^2$ of the COSMOS field. High-resolution NIRCam imaging enables robust size and morphological measurements, while multiwavel…

A Precise Metallicity and Carbon-to-Oxygen Ratio for a Warm Giant Exoplanet from its Panchromatic JWST Emission Spectrum
Lindsey S. Wiser, Taylor J. Bell, Michael R. Line, Everett Schlawin, Thomas G. Beatty, Luis Welbanks, Thomas P. Greene, Vivien Parmentier, Matthew M. Murphy, Jonathan J. Fortney, Kenny Arnold, Nishil Mehta, Kazumasa Ohno, Sagnick Mukherjee

A Precise Metallicity and Carbon-to-Oxygen Ratio for a Warm Giant Exoplanet from its Panchromatic JWST Emission Spectrum
WASP-80 b, a warm sub-Jovian (equilibrium temperature ~820 K, 0.5 Jupiter masses), presents an opportunity to characterize a rare gas giant exoplanet around a low-mass star. In addition, its moderate temperature enables its atmosphere to host a range of carbon and oxygen species (H$_2$O, CH$_4$, CO, CO$_2$, NH$_3$). In this paper, we present a panchromatic emission spectrum of WASP-80 b, the first gas giant around a late K/early M-dwarf star and the coolest planet for which the James Webb Space…

Brightest Group Galaxies IV: Probing Size--Mass Relation and Morphological Quenching in COSMOS-Web from $z = 3.7$
Ghassem Gozaliasl, Lilan Yang, Greta Toni, Fatemeh Abedini, Rafael C. Arango-Toro, Arif Babul, Caitlin M. Casey, Nima Chartap, Nicole E. Drakos, Andreas L. Faisst, Alexis Finoguenov, Maximilien Franco, Gavin Leroy, G\"unther Hasinger, Hossein Hatamnia, Olivier Ilbert, Shuowen Jin, Darshan Kakkad, Atousa Kalantari, Jeyhan S. Kartaltepe, Ali Ahmad Khostovan, Anton M. Koe…

Brightest Group Galaxies IV: Probing Size--Mass Relation and Morphological Quenching in COSMOS-Web from $z = 3.7$
We present a comprehensive study of the structural evolution of Brightest Group Galaxies (BGGs) from redshift $z \simeq 0.08$ to $z = 3.7$ using the \textit{James Webb Space Telescope}'s 255h COSMOS-Web program. This survey provides deep NIRCam imaging in four filters (F115W, F150W, F277W, F444W) across $\sim 0.54~\mathrm{deg}^2$ and MIRI coverage in $\sim 0.2~\mathrm{deg}^2$ of the COSMOS field. High-resolution NIRCam imaging enables robust size and morphological measurements, while multiwavel…

Continuous helium absorption from the leading and trailing tails of WASP-107b
Vigneshwaran Krishnamurthy, Yann Carteret, Caroline Piaulet-Ghorayeb, Jared Splinter, Dhvani Doshi, Michael Radica, Louis-Philippe Coulombe, Romain Allart, Vincent Bourrier, Nicolas B. Cowan, David Lafreni\`ere, Lo\"ic Albert, Lisa Dang, Ray Jayawardhana, Doug Johnstone, Lisa Kaltenegger, Adam B. Langeveld, Stefan Pelletier, Jason F. Rowe, Pierre-Alexis Roy, Jake Taylor, Jake D. Turner

Continuous helium absorption from the leading and trailing tails of WASP-107b
The detection of helium escaping the atmosphere of exoplanets has revolutionized our understanding of atmospheric escape and exoplanetary evolution. Using high-precision spectroscopic observations from the James Webb Space Telescope (JWST) NIRISS-SOSS mode, we report the detection of significant helium absorption during the pre-transit phase of WASP-107b (17$σ$), as well as in the transit and post-transit phases. This unique continuous helium absorption begins approximately 1.5 hours before th…

This https://arxiv.org/abs/2505.04825 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

SHELLQs. Bridging the gap: JWST unveils obscured quasars in the most luminous galaxies at z > 6
The unprecedented sensitivity of the James Webb Space Telescope (JWST) has uncovered a surprisingly abundant population of mildly obscured, low-luminosity active galactic nuclei (AGNs) in the epoch of reionization (EoR). However, the link between these objects and classical unobscured quasars remains a mystery. Here we report the discovery of obscured quasars hosted by the most luminous galaxies at $z > 6$, possibly bridging the gap between the two AGN populations. The 13 objects presented here…

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…

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…