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@arXiv_astrophCO_bot@mastoxiv.page
2026-08-06 07:41:31

Revisiting the equation of state of dark energy from DESI BAO with SNe Ia and CMB
Jie Zheng, Da-Chun Qiang, Zhi-Qiang You, Darshan Kumar
arxiv.org/abs/2608.04353 arxiv.org/pdf/2608.04353 arxiv.org/html/2608.04353
arXiv:2608.04353v1 Announce Type: new
Abstract: The Dark Energy Spectroscopic Instrument (DESI) measurements of baryon acoustic oscillations (BAO) have recently shown a mild preference for dynamical dark energy over the standard $\rm \Lambda$CDM model. In this paper, we analyze the $w_0w_a$CDM model using DESI BAO DR2, Pantheon SNe Ia, and Planck 2018 CMB distance prior data. To examine how different parts of the data affect the apparent deviation from $\rm \Lambda$CDM, we adopt two complementary redshift-cut strategies, dividing the dataset into $zz_{\rm cut}$ subsamples. We find that the most noticeable shifts occur when BAO and SNe Ia data in the redshift range $z\sim0.4$--$0.8$ are included, reaching a significance of about $\sim2\sigma$. Within this framework, the inclusion of higher-redshift measurements progressively weakens this deviation and brings the constraints closer to the $\rm \Lambda$CDM expectation. Moreover, the information criteria show no statistically significant preference between the $w_0w_a$CDM and $\rm \Lambda$CDM models, while the Bayesian information criterion consistently favors the $\rm \Lambda$CDM model. In addition, a parameter-shift consistency test reveals no statistically significant tension between complementary redshift subsamples. Within the DESI BAO DR2, Pantheon , and CMB distance prior framework adopted here, these results do not provide statistically robust evidence favoring the $w_0w_a$CDM model over $\rm \Lambda$CDM. They instead indicate that the apparent parameter shifts under different redshift cuts may be affected by statistical fluctuations and by the limited precision and number of datapoints in the current subsamples. Our analysis provides a complementary redshift-dependent diagnostic for assessing how the inferred cosmological constraints vary under different redshift selections.
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@arXiv_astrophGA_bot@mastoxiv.page
2026-09-09 09:35:48

Small-Scale Clustering of Primordial Black Holes: The Little Red Dot Mass Function and the High-Redshift Galaxy Tension
Borui Zhang, Wei-Xiang Feng, Haipeng An
arxiv.org/abs/2609.09078 arxiv.org/pdf/2609.09078 arxiv.org/html/2609.09078
arXiv:2609.09078v1 Announce Type: new
Abstract: Supermassive black holes (SMBHs) in "little red dots" (LRDs) discovered the James Webb Space Telescope (JWST) may result from runaway mergers of primordial black holes (PBHs) in clusters---through long--short mode coupling on small scales in the early Universe. In this framework, we derive the SMBH mass function, together with the compactness and overmassive features of LRDs. We also estimate that the dense gas residing in PBH clusters is consistent with LRD observations. In addition, SMBHs formed from PBH clusters can help accelerate galaxy formation at high redshifts, thus alleviating tension with $\Lambda$CDM cosmology.
toXiv_bot_toot

@cosmos4u@scicomm.xyz
2026-06-23 15:53:13

MXDFz4.4 - a LyC Emitter 250 Myr after the Epoch of Reionization and a First Test of Lyα Morphology as a Tracer of LyC Escape at High Redshift: #Galaxy Transforming Neighborhood: science.nasa.gov/missions/hubb

@arXiv_mathKT_bot@mastoxiv.page
2026-08-11 10:05:03

Replaced article(s) found for math.KT. arxiv.org/list/math.KT/new
[1/1]:
- The Redshift Bound from Quillen-Lichtenbaum
Shay Ben-Moshe
arxiv.org/abs/2608.02180 mastoxiv.page/@arXiv_mathKT_bo
- Relative cyclotomic structures and equivariant complex cobordism
Andrew J. Blumberg, Michael A. Mandell, Allen Yuan
arxiv.org/abs/2310.02348 mastoxiv.page/@arXiv_mathAT_bo
- Partial Bloch--Kato Selmer groups of $B$-pairs as delta functors
Rustam Steingart
arxiv.org/abs/2510.00775 mastoxiv.page/@arXiv_mathNT_bo
- Higher Lefschetz formulas on {\Gamma}-proper manifolds
Paolo Piazza, Hessel Posthuma, Yanli Song, Xiang Tang
arxiv.org/abs/2512.14318 mastoxiv.page/@arXiv_mathDG_bo
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-09-09 09:21:30

J023721.13$-$010528.5: A Giant $S$-shaped Radio Galaxy Showing Four Episodes of Jet Activity
Pavan Vijay Khadekar, Dharam Vir Lal, Ramana Athreya
arxiv.org/abs/2609.08506 arxiv.org/pdf/2609.08506 arxiv.org/html/2609.08506
arXiv:2609.08506v1 Announce Type: new
Abstract: We present high-sensitivity, high-resolution radio observations of J023721.13$-$010528.5 using the upgraded Giant Metrewave Radio Telescope in band-3 (250--500\,MHz) and band-4 (550--950\,MHz), along with MeerKAT (1280\,MHz) and VLA (3\,GHz) survey images. The radio source, hosted by a bright cluster galaxy at redshift $z=0.372$, is a giant radio galaxy with a projected linear size between the outermost hotspots of 1.2~Mpc and is one of the largest $S$-shaped radio sources known. Its radio morphology revealed four pairs of components straddling the radio core, which were also local maxima in profiles of radio flux densities and equipartition energy density measured along the radio lobes. Spatially resolved multi-frequency spectral analysis showed progressively older emission from the inner to the outer components, spanning approximately 4--21 Myr. The high degree of symmetry of the inner three component-pairs with respect to the radio core makes it improbable that these are randomly located knots in the radio jet. Therefore, we present J023721.13$-$010528.5 as the prototype of a new class of radio galaxies with four episodes of jet activity --- a quadruple-double radio galaxy. We suggest that giant $S$-shaped radio sources may be among the most promising targets for identifying and studying multi-epoch radio jet activity, since their large linear sizes and jet-axis evolution can spatially separate hotspots from successive episodes, making them easier to detect and analyse.
toXiv_bot_toot

@arXiv_mathAT_bot@mastoxiv.page
2026-08-11 10:04:03

Replaced article(s) found for math.AT. arxiv.org/list/math.AT/new
[1/1]:
- Relative cyclotomic structures and equivariant complex cobordism
Andrew J. Blumberg, Michael A. Mandell, Allen Yuan
arxiv.org/abs/2310.02348 mastoxiv.page/@arXiv_mathAT_bo
- A multiplicative version of the tom Dieck splitting
Andrew J. Blumberg, Michael A. Mandell
arxiv.org/abs/2505.02721 mastoxiv.page/@arXiv_mathAT_bo
- A rank-based distance for interval modules and Wasserstein stability of persistence landscapes
Peter Bubenik, Wanchen Zhao
arxiv.org/abs/2509.20921 mastoxiv.page/@arXiv_mathAT_bo
- The rank-five Peterson hit problem, the Singer transfer, and canonical Milnor-operation layers
Dang Vo Phuc
arxiv.org/abs/2511.11745 mastoxiv.page/@arXiv_mathAT_bo
- The Algebra of Categorical Spectra
Naruki Masuda
arxiv.org/abs/2605.03114 mastoxiv.page/@arXiv_mathAT_bo
- Visualizing Local Maxima of the Ohio overdose epidemic with Vineyards
Nicholas Bermingham, David White, Nathan Willey
arxiv.org/abs/2607.05710 mastoxiv.page/@arXiv_mathAT_bo
- Chern--Simons-type $3$-cocycles and $\mathbb{Q}/\mathbb{Z}$-torsion in the third homology of disc...
Takefumi Nosaka
arxiv.org/abs/2601.07230 mastoxiv.page/@arXiv_mathGT_bo
- The Topology of $k$-Robust Clique Complexes in Grid-like Graphs
Marek Filakovsk\'y
arxiv.org/abs/2602.11365 mastoxiv.page/@arXiv_mathCO_bo
- The Redshift Bound from Quillen-Lichtenbaum
Shay Ben-Moshe
arxiv.org/abs/2608.02180 mastoxiv.page/@arXiv_mathKT_bo
toXiv_bot_toot

@arXiv_astrophCO_bot@mastoxiv.page
2026-08-05 08:17:11

Integrated cosmological memory: A dark-siren method to probe dark energy
Indranil Chakraborty, Sayantan Ghosh, Susmita Jana, Archana Pai, S. Shankaranarayanan
arxiv.org/abs/2608.03739 arxiv.org/pdf/2608.03739 arxiv.org/html/2608.03739
arXiv:2608.03739v1 Announce Type: new
Abstract: Gravitational-wave (GW) cosmology is currently bottlenecked by the scarcity of electromagnetic counterparts for bright sirens and the systematic uncertainties of galaxy catalogs for dark sirens. We propose a purely gravitational resolution using the Integrated Cosmological Memory (ICM)-the cumulative GW strain encoded in the spacetime geometry of an expanding Universe. While the GW transient emitted by the source provides the luminosity distance, the ICM accumulates a mathematically distinct integral of the cosmic expansion history. We demonstrate that extracting both observables from a single binary merger completely breaks the distance-redshift degeneracy within the gravitational sector. This establishes a novel, catalog-free dark siren framework for third-generation GW detector networks. Crucially, the resulting constraints on late-time dark energy are only weakly sensitive to the local expansion rate, providing a robust cosmological probe that can potentially mitigate the impact of the H0 tension.
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-09-09 09:27:09

Weak cool core, weak turbulence: XRISM, XMM-Newton and Chandra spectroscopy of the core of Abell 1413
Egemen Gormez, Murat Hudaverdi
arxiv.org/abs/2609.08778 arxiv.org/pdf/2609.08778 arxiv.org/html/2609.08778
arXiv:2609.08778v1 Announce Type: new
Abstract: We present the first XRISM spectroscopy of the core of Abell 1413 (z = 0.143), combining 104.7 ks of Resolve with archival XMM-Newton and Chandra spectra of a matched sky region. A1413 is hot, massive and relaxed but lacks a strong cool core (t_cool = 6.4 Gyr), a regime in which the low turbulence reported to date has been tested only once, in A3571. The Resolve spectrum requires a single velocity-broadened component with kT = 7.06 ( 0.33, -0.43) keV and a line-of-sight velocity dispersion sigma_v = 170 ( 25, -24) km/s (M_3D = 0.217). The bulk velocity relative to the brightest cluster galaxy, v_bulk = -24 /- 26 (z_ICM) /- 71 (z_BCG) km/s, is limited by the optical redshift rather than by Resolve, and disfavours coherent line-of-sight sloshing. The non-thermal pressure fraction, 2.5 /- 0.7 per cent, implies a hydrostatic mass bias b < 2.5 per cent, comparable to the strong cool-core cluster A2029 (2.6 /- 0.3 per cent) and, at matched sampling scale, if anything below it. With A3571 (1.3 /- 0.3 per cent), to which A1413 rescales within 0.2 sigma, two weak cool cores now show that this quiescence does not require central cooling. The resolved Fe-K He-alpha complex gives Fe = 0.38 /- 0.03 (stat) /- 0.04 (sys) solar; Ni/Fe, separated from Fe K-beta for the first time, is solar, as is the pattern as a whole. The Ne, Mg and Si lines that set Ne/Fe, Mg/Fe and Si/Fe lie below 2 keV, where our instruments disagree by 10-20 per cent; we therefore do not regard the SNIa fraction as constrained.
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-09-09 09:33:33

Active galactic nucleus activity in brightest cluster galaxies at intermediate redshifts in Sunyaev-Zel'dovich--selected clusters
N. Hatamkhani, R. E. Skelton, J. Delhaize, M. Hilton, S. I. Loubser, N. Gupta, K. M. Mogotsi
arxiv.org/abs/2609.09049 arxiv.org/pdf/2609.09049 arxiv.org/html/2609.09049
arXiv:2609.09049v1 Announce Type: new
Abstract: Context. Brightest cluster galaxies (BCGs) host powerful active galactic nuclei (AGNs) and help regulate the heating--cooling balance of the intracluster medium. While radio-mode feedback is well established locally, its prevalence at intermediate redshifts remains poorly constrained. Aims. We investigate the incidence, accretion state, and host-galaxy properties of AGNs in BCGs in Sunyaev--Zel'dovich (SZ)-selected clusters at $0.3 < z < 0.8$, testing dependences on cosmic epoch, cluster mass, and dynamical state. Methods. We analyse 171 BCGs from the Atacama Cosmology Telescope SZ catalogue, combining Southern African Large Telescope spectroscopy, WISE mid-infrared photometry, and Rapid ASKAP Continuum Survey radio data with \textsc{X-CIGALE} modelling to derive stellar masses, star formation rates, and Eddington-scaled accretion rates. Results. Thirty-eight BCGs (22%) host radio-loud AGNs. Only two ($\sim$5%) are high-excitation radio galaxies; the remainder are low-excitation systems. Most AGNs have low Eddington ratios ($-3 \lesssim \log_{10}\lambda_{\mathrm{Edd}} \lesssim -1$), consistent with radiatively inefficient accretion. Accretion efficiency increases with redshift, while correlations with cluster mass and dynamical state are weak. Radio luminosity is independent of cluster mass. Compared to field radio AGNs, BCG radio-loud AGNs have similar radio powers but are hosted by galaxies $\sim0.8$ dex more massive. Conclusions. BCG radio-loud AGNs at $0.3 < z < 0.8$ are predominantly low-excitation, radiatively inefficient systems, indicating that maintenance-mode accretion was widespread in massive clusters ($M_{500c} \simeq 3.2 \times 10^{14},M_\odot$) by $z \sim 1$. Accretion appears regulated primarily by fuel availability and cosmic evolution rather than global cluster properties, while the cluster environment mainly sets the host-galaxy mass scale.
toXiv_bot_toot

@arXiv_astrophCO_bot@mastoxiv.page
2026-08-06 07:57:46

Characterising the epoch of reionisation using the cross-correlation of the kSZ effect and CMB lensing
Niall MacCrann, Christopher Cain, Aleksandra Kusiak, Fiona McCarthy, Alexander Van Engelen, Darby Kramer, William R. Coulton, Frank J. Qu
arxiv.org/abs/2608.04868 arxiv.org/pdf/2608.04868 arxiv.org/html/2608.04868
arXiv:2608.04868v1 Announce Type: new
Abstract: We investigate the cross-correlation of the kinematic Sunyaev-Zeldovich (kSZ) effect with lensing of the cosmic microwave background (CMB) as a probe of the epoch of reionisation. During reionisation, bubbles of ionised electrons form around overdensities, generating temperature perturbations in the CMB via the kSZ effect, which correlate with the projected matter density field probed by CMB lensing. We demonstrate using AMBER simulations that this effect can be probed via cross-correlating the squared kSZ field with the CMB lensing potential, and that the signal is sensitive to the duration and midpoint of reionisation. We forecast that for a Simons Observatory-like experiment with 5$\mu$K-arcmin white noise, covering 40% of the sky, the signal could be marginally detected at $S/N$ = 2 to 3. Meanwhile, a futuristic experiment like CMB-HD could provide a measurement of $S/N \sim 50$, yielding informative constraints on reionisation scenarios. We investigate potential challenges in measuring the signal and explore mitigation for each: contamination from extragalactic foregrounds at low redshift, contamination of the kSZ-squared estimator by lensing, and other estimator biases.
toXiv_bot_toot

@cosmos4u@scicomm.xyz
2026-07-29 20:07:59

An LRD-like Nucleus at the Heart of an IR-bright Galaxy and its Implications for High-redshift LRDs: #LittleRedDots

@arXiv_astrophGA_bot@mastoxiv.page
2026-07-22 08:52:17

Replaced article(s) found for astro-ph.GA. arxiv.org/list/astro-ph.GA/new
[1/2]:
- GA-NIFS: Powerful and frequent outflows in moderate-luminosity active galactic nuclei at $z\sim3-6$
Giacomo Venturi, et al.
arxiv.org/abs/2512.09996 mastoxiv.page/@arXiv_astrophGA
- ALMA High-J CO Spectroscopy of High-Redshift Galaxies. II. 0.03" Resolution CO Kinematics Reveal ...
Ken-ichi Tadaki
arxiv.org/abs/2603.01352 mastoxiv.page/@arXiv_astrophGA
- Very long-term relaxation of harmonic 1D self-gravitating systems
Kerwann Tep, Jean-Baptiste Fouvry, Christophe Pichon
arxiv.org/abs/2603.11238 mastoxiv.page/@arXiv_astrophGA
- The tidal evolution of satellite galaxies in cosmological simulations: insights from COLIBRE
Feihong He, et al.
arxiv.org/abs/2604.03105 mastoxiv.page/@arXiv_astrophGA
- Deriving volume density profiles of filaments from observed surface densities
Alexander Men'shchikov, Guo-Yin Zhang
arxiv.org/abs/2604.12570 mastoxiv.page/@arXiv_astrophGA
- Reduced Incidence of Little Red Dots at z < 3 from Number Density and Halo Mass Evolution
Chenxuan Zhang, Huanian Zhang, Qingwen Wu, Luis C. Ho, Jian-Min Wang
arxiv.org/abs/2606.02773 mastoxiv.page/@arXiv_astrophGA
- The Hubble Missing Globular Clusters Survey IV. Ultra-faint compact satellites of the Milky Way. ...
M. Bellazzini, et al.
arxiv.org/abs/2606.12517 mastoxiv.page/@arXiv_astrophGA
- Nebular_AGN: A CIGALE module for fitting AGN emission lines
Hao Zhang, Patrice Theule, Veronique Buat, Denis Burgarella, Estelle Pons, Mederic Boquien
arxiv.org/abs/2606.14643 mastoxiv.page/@arXiv_astrophGA
- Assembly bias from nuisance to probe I: the relation between galactic conformity and the linear m...
Nelson Padilla, Ivan Lacerna, Dante Paz
arxiv.org/abs/2607.04022 mastoxiv.page/@arXiv_astrophGA
- Enabling Cosmic Web Analysis at Gigaparsec Scales: A Multi Block Approach for DisPerSE
Ankit Singh, Frazer Pearce, Meghan Gray, Gustavo Yepes
arxiv.org/abs/2607.14785 mastoxiv.page/@arXiv_astrophGA
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-07-22 08:03:31

Vz-GAL Dusty Star-Forming Galaxies: Revisiting the CO-H2 Conversion Factor Tension
Prachi Prajapati, Axel Weiss, Dominik Riechers, Tom J. L. C. Bakx, Leindert A. Boogaard, Diana Ismail, Pierre Cox, Andrew J. Baker, Roberto Neri, Matthew Lehnert, Chentao Yang, Emilio Romano-Diaz, Hiddo S. B. Algera, Stefano Berta, Edoardo Borsato, Kirsty M. Butler, Asantha Cooray, Bethany Jones, Amelie Saintonge, Paul van der Werf
arxiv.org/abs/2607.18440 arxiv.org/pdf/2607.18440 arxiv.org/html/2607.18440
arXiv:2607.18440v1 Announce Type: new
Abstract: The CO luminosity-to-H$_2$ mass conversion factor ($\alpha_{CO}$) remains a debated uncertainty in determining molecular gas masses of high-redshift dusty star-forming galaxies (DSFGs). Dynamical mass constraints have often favored $\alpha_{CO}=0.8$~$M_{\odot}~{(K~km~{s}^{-1}~{pc}^{2})}^{-1}$, whereas dust- and radiative-transfer-based methods imply higher values. We revisit this ``tension" using the largest homogeneous sample of 21 unlensed $z\sim1-4$ DSFGs, with securely measured \coonezero luminosities from the VLA \vzgal survey and resolved ($\sim{0.1}^{\prime\prime}$) ALMA 1~mm dust continuum imaging. For 12 galaxies with robust modeling constraints, we derive molecular gas masses using dust spectral energy distribution modeling and the TUNER LVG framework, adopting a solar-metallicity gas-to-dust mass ratio of 100. Although not fully independent due to shared assumptions on dust properties, these approaches yield mutually consistent gas masses corresponding to $\alpha_{CO}\sim1.5-11.5$, with a median near the Galactic $\alpha_{CO}=4.3$. Isotropic virial dynamical masses agree with these gas masses when realistic molecular gas sizes are adopted, while our proposed ``mixed" (rotating, pressure-supported, thick-disk) estimator systematically underestimates dynamical masses, producing low $\alpha_{CO}$ limits. Using GN20 ($z=4.055$) as a case study, we show that resolved gas geometry and kinematics reconcile the discrepancy with LVG-derived $\alpha_{CO}$. Our results suggest that current data do not require $\alpha_{CO}=0.8$, and intermediate to near-Galactic values remain dynamically viable given uncertainties in gas geometry, dust properties, and gas-to-dust ratios. Further progress in calibrating $\alpha_{CO}$ in the early universe will require resolved molecular gas observations, physically motivated ISM modeling, and stringent constraints on dust properties.
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-07-22 08:11:55

An (in)complete NIRSpec census of Balmer absorption in Type 1 AGN -- radiation-driven outflows in little red dots, quasars and variable stars
Ignas Juod\v{z}balis, Xihan Ji, Francesco D'Eugenio, Jan Scholtz, Roberto Maiolino, Amanda Stoffers, Alessandro Marconi, Elena Bertola, Andrew J. Bunker, Stefano Carniani, Giovanni Cresci, Emma Curtis-Lake, Zheng Ma, Cosimo Marconcini, Eleonora Parlanti, Pierluigi Rinaldi, Brant Robertson, Hannah \"Ubler, Giacomo Venturi, Junyu Zhang
arxiv.org/abs/2607.19057 arxiv.org/pdf/2607.19057 arxiv.org/html/2607.19057
arXiv:2607.19057v1 Announce Type: new
Abstract: A notable achievement of the first generation of JWST surveys was the discovery of an abundance of faint high-redshift ($z > 4$) broad-line active galactic nuclei (AGN) in the $L_{\rm bol} < 10^{45}$~erg~s$^{-1}$ regime, previously only accessible at $z < 1$. The high prevalence of absorption features in their broad hydrogen lines is one of the peculiarities of a significant fraction of this new population. In this paper, we conduct a broad census of Balmer absorption in a sample of 47 Type-1 AGN spanning $2 < z < 7$. Accounting for incompleteness of JWST spectroscopic data, we estimate that $44_{-6}^{ 21}$~\% of Little Red Dots (LRDs) have absorption in \Has while the incidence rate is $< 25$~\% (at 2$\sigma$) in Little Blue Dots (LBDs). Additionally, R1000 JWST/NIRSpec data is strongly resolution limited, implying an inability to disentangle Doppler broadening in the absorption from optical depth effects. This is alleviated with R2700 observations, although some degeneracies remain. We find a significant correlation between the velocity of the Balmer absorption and the [OIII]5007 narrow line luminosity, suggesting a common driving mechanism. We do not find any other significant correlations (and do not confirm previously claimed correlations) between Balmer absorption and other spectral properties of LRDs (except for the expected correlation between \Has and \Hbs absorption velocities). Comparing LRDs, quasars and stellar \Has absorbers, we establish that absorption in both LRDs and broad absorption line quasars is consistent with radiatively driven outflows, echoing the physics of variable stars yet occurring at vastly different scales.
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-07-22 08:11:07

Bright Galaxies at Cosmic Dawn: A Cloud-Scale Star Formation Model Unifying Variable SFE, IMFs, and Stochasticity
Elie Cueto, Anne Hutter
arxiv.org/abs/2607.18868 arxiv.org/pdf/2607.18868 arxiv.org/html/2607.18868
arXiv:2607.18868v1 Announce Type: new
Abstract: To investigate the origins of the high abundance of UV-bright galaxies at z > 10, we present a new semi-analytic model that bridges the gap between small-scale star formation physics and large-scale galaxy evolution by explicitly tracking discrete star-forming clouds within smoothly evolving dark matter potentials. Unlike conventional semi-analytic models, our approach naturally captures the stochasticity of star formation, allowing us to isolate how cloud properties, star formation efficiencies (SFEs), and stellar initial mass functions (IMFs) shape the star-formation burstiness of early galaxies. Clouds are drawn sequentially from a cloud mass distribution, assigned an SFE and IMF depending on cloud mass, metallicity, and redshift, and evolve under the influence of short-timescale stellar feedback. We identify three distinct star formation regimes arising from the interplay between cloud masses, densities, and feedback timescales: a stochastic, feedback-limited regime in low-mass halos with long quiescent phases; a bursty regime regulated by the cloud mass distribution; and a smooth, continuous regime in massive halos. Our fiducial model adopts a dynamic IMF, an SFE linked to cloud properties and the IMF, and massive, moderately dense clouds. Varying assumptions reveals that top-heavy IMFs and enhanced SFEs in massive clouds amplify burstiness, while altering the upper cloud mass or density normalisation is secondary. Among model ingredients, the IMF most strongly impacts the UV luminosity function (LF), while switching to a constant SFE boosts the faint end, and reducing the maximum cloud mass decreases the bright end. These results demonstrate that cloud-scale physics critically shape early galaxy UV luminosity distributions.
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-07-22 07:55:10

Star formation powers optical line emission from the CGM
Huanian Zhang, Lizhi Xie, Zhijie Qu, Dennis Zaritsky, Luis C. Ho, Min Bao, Fabio Fontanot, Michaela Hirschmann, Chenxu Liu, Gabriella De Lucia, Enci Wang, Haoyan Zheng
arxiv.org/abs/2607.18385 arxiv.org/pdf/2607.18385 arxiv.org/html/2607.18385
arXiv:2607.18385v1 Announce Type: new
Abstract: Using integral field spectroscopy, we explore the disk-halo interface, or the inner circumgalactic medium (CGM), of individual galaxies by constructing and analyzing emission-line maps for a large sample (72) of normal, low-redshift galaxies spanning three orders of magnitude in stellar mass and four orders in star formation rate (SFR). We find a steep turnover occurring at $(1-2) R_e$ in the H$\alpha$, [O {\small II}], and [O {\small III}] line emission radial profiles. Beyond this radius, the slope of the line emission radial profiles becomes shallower as the SFR of the central galaxy decreases, which might reflect the strength of the feedback processes. The line emission fluxes at large radius ($(5-10) R_e$ or $\sim (0.1-0.25)r_{\rm vir}$) correlate with the galaxy's SFR, but not with its stellar mass. These findings suggest that ionizing photons escaping from star-forming regions in the central galaxy account for the observed emission line fluxes from the inner CGM, with escape fractions inferred from the [O {\small III}] and [O {\small II}] ratio. Different state-of-the-art theoretical models do not agree on the predicted dependence of cool gas on the SFR of the central galaxies, highlighting the importance of CGM emission line measurements to distinguish between different subgrid models for star formation and feedback processes.
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-07-22 08:12:01

Physical Properties of 6.7 Million Galaxies from the DESI Bright Galaxy Survey: Spectral Fitting and Systematic Tests with Mock Spectra
Niu Li, Hu Zou, Jinfu Gou, Weijian Guo, Wenxiong L, Haoming Song, Jipeng Sui, Xi Tan, Yunao Xiao, Jingyi Zhang
arxiv.org/abs/2607.19162 arxiv.org/pdf/2607.19162 arxiv.org/html/2607.19162
arXiv:2607.19162v1 Announce Type: new
Abstract: We present a comprehensive analysis of the physical properties of galaxies in the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) Bright Galaxy Survey (BGS), based on full spectral fitting of $\sim 6.7$ million galaxy spectra. Using a customized spectral fitting pipeline, we derive key physical parameters including stellar mass, stellar velocity dispersion, stellar population age, dust attenuation, and emission-line properties. To quantify the reliability and systematic uncertainties of our measurements, we construct a large set of mock spectra that closely reproduce the observed properties of DESI data, including realistic noise and spectral features. By comparing the recovered parameters with the known inputs, we assess the performance of the spectral fitting as a function of stellar continuum signal-to-noise ratio (S/N, defined as the ratio of the median continuum flux to its associated error) and redshift. We find that stellar masses can be robustly recovered with negligible bias for spectra with $\mathrm{S/N} \gtrsim 5$, while low-S/N spectra ($\mathrm{S/N} \lesssim 5$) show a mild systematic overestimation of $\sim 0.1$ dex and increased scatter. Similar trends are observed for stellar population parameters, while emission-line fluxes are recovered with high accuracy and minimal bias. We further validate our stellar mass estimates by comparison with independent measurements from photometric spectral energy distribution fitting, finding good overall consistency within the expected systematic uncertainties. The value-added catalog presented in this work enables a wide range of statistical studies of galaxy evolution with DESI, and provides a foundation for future analyses.
toXiv_bot_toot

@arXiv_astrophGA_bot@mastoxiv.page
2026-07-21 09:39:17

Replaced article(s) found for astro-ph.GA. arxiv.org/list/astro-ph.GA/new
[1/3]:
- CO Observations of Early-mid Stage Major Mergers in the MaNGA Survey
Yu, Fang, Xu, Feng, Feng, Gao, Jiang, Lisenfeld
arxiv.org/abs/2404.18999 mastoxiv.page/@arXiv_astrophGA
- A first systematic study of [OIII] 88$\mu$m at $z>8$: two luminous oxygen lines and a powerful io...
Hiddo S. B. Algera, et al.
arxiv.org/abs/2512.14486 mastoxiv.page/@arXiv_astrophGA
- Electron temperature relations and the direct N, O, Ne, S and Ar abundances of 49959 star-forming...
D. Scholte, et al.
arxiv.org/abs/2601.02463 mastoxiv.page/@arXiv_astrophGA
- The Role of Inner Halo Angular Momentum (Spin) in Shaping Dark Matter Bars in Milky Way Analogs
Shouvik Ghosh, Sandeep Kumar Kataria
arxiv.org/abs/2601.14420 mastoxiv.page/@arXiv_astrophGA
- GA-NIFS: Dissecting The Alchemised: JWST reveals turbulent metal-poor gas fuelling a co-spatial s...
Robert G. Pascalau, et al.
arxiv.org/abs/2603.00232 mastoxiv.page/@arXiv_astrophGA
- The Star Formation History of WLM from Asymptotic Giant Branch Stars and The Discovery of a Candi...
Abigail J. Lee, Daniel R. Weisz, Andrew E. Dolphin, Alessandro Savino
arxiv.org/abs/2603.00243 mastoxiv.page/@arXiv_astrophGA
- Two Exciting High-redshift Galaxy Candidates Turn Out to Be Two Exciting Ultra-cool Brown Dwarfs
Maru\v{s}a Brada\v{c}, et al.
arxiv.org/abs/2604.23668 mastoxiv.page/@arXiv_astrophGA
- PEARLS: JWST Counterparts of Micro-Jy Radio Sources in the NEP Time Domain Field. II. All Four Sp...
S. P. Willner, et al.
arxiv.org/abs/2605.17040 mastoxiv.page/@arXiv_astrophGA
- Eppur non si trovano Vol. 3: Phoebe -- a Mirage of a Primordial Black Hole
Andrzej Udalski, Przemek Mr\'oz
arxiv.org/abs/2606.19442 mastoxiv.page/@arXiv_astrophGA
- LEGGOS I: The JWST LEGGOS Survey -- LEnsing and Galaxy Growth: Observing Substructures -- Unpacks...
Gourav Khullar, et al.
arxiv.org/abs/2606.20845 mastoxiv.page/@arXiv_astrophGA
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