M. Chiaberge

The quest for high-redshift radio galaxies. II. Discovery of the most powerful known radio galaxy at z=4.946.

B. Balmaverde, Alessandro Capetti, M. Chiaberge, Francesco Massaro et autres

As part of our quest for high-redshift radio galaxies (HzRGs), we present the results obtained from optical spectroscopy leading to the confirmation of one HzRG candidate selected using the Lyman break technique. The optical emission, associated with the radio source TXS 2354+015, …

Radio selection of heavily obscured AGN in the J1030 field: Unraveling a missing Compton-thick population

Giovanni Mazzolari, R. Gilli, M. Mignoli, M. Brusa et autres

Context. Models of supermassive black holes (SMBHs) and galaxy coevolution, simulations, and recent JWST observations suggest that the population of heavily obscured, Compton-thick (CTK) active galactic nuclei (AGNs) at high redshift might be underestimated by X-ray surveys. To retrieve a complete census …

it, de, us, es, fr, nl (code pays fourni par la source)

Vision-Language Model Ensembles Achieve Human-Expert Accuracy for Galaxy Merger Classification

M. Chiaberge, Elias Stengel-Eskin, Massimo Stiavelli, Colin Norman

We present a proof-of-concept study demonstrating that an ensemble of Vision--Language Models (VLMs) combined using a Bayesian statistical framework can classify galaxy merger morphologies with accuracy comparable to trained human experts. We deploy 15 VLM classifier configurations, spanning four model architectures (Gemma-4 …

Vision-Language Model Ensembles Achieve Human-Expert Accuracy for Galaxy Merger Classification

M. Chiaberge, Elias Stengel-Eskin, Massimo Stiavelli, Colin Norman

We present a proof-of-concept study demonstrating that an ensemble of Vision--Language Models (VLMs) combined using a Bayesian statistical framework can classify galaxy merger morphologies with accuracy comparable to trained human experts. We deploy 15 VLM classifier configurations, spanning four model architectures (Gemma-4 …

us (code pays fourni par la source)

The case for super-Eddington accretion in JWST broad-line active galactic nuclei during the first billion years

Erini Lambrides, Rebecca L. Larson, Kristen Garofali, Andrew F. Ptak et autres

A multitude of studies of data recorded by the James Webb Space Telescope (JWST) reveal a surprising overabundance of over-massive accreting supermassive black holes, leading to a deepening tension between theory and observation for the first billion years of cosmic time. Across …

us, it, ch (code pays fourni par la source)

Mapping Feedback Signatures in 3C 297: A Quasar-host Merger at Cosmic Noon

Chetna Duggal, C. P. O’Dea, Stefi Alison Baum, J. Jiwa et autres

Abstract We present a study of quasar host galaxy 3C 297, which is home to a powerful bent-jet radio source suggesting vigorous interaction with a dense interstellar medium (ISM) and/or jet precession. Archival Hubble Space Telescope (HST) imaging showed interestingly perturbed morphology …

A big red dot at cosmic noon

F. Loiacono, R. Gilli, M. Mignoli, Giovanni Mazzolari et autres

We report the discovery of a little red dot (LRD), dubbed BiRD (‘big red dot’), at z ∼ 2.33 in the field around the z ∼ 6.3 quasar SDSS J1030+0524. Using JWST/NIRCam images, we identified it as a bright outlier in the …

de, it, us, fr, es, gb (code pays fourni par la source)

A Nitrogen-rich AGN Powering a Large Ionizing Bubble at z=8.63

Takahiro Morishita, M. Stiavelli, Charlotte A. Mason, Roberta Tripodi et autres

We report the detection of Ly$α$ in CANUCS-LRD-z8.6, a recently discovered AGN at z = 8.63 by Tripodi et al. (2024), in new NIRSpec/MSA G140H/F070LP observations. We detect broad Ly$α$ emission (FWHM $= 1540 \pm 260$ km/s) near the systemic velocity, which …

A big red dot at cosmic noon

F. Loiacono, R. Gilli, M. Mignoli, Giovanni Mazzolari et autres

We report the discovery of a little red dot (LRD), dubbed BiRD ('big red dot'), at $z=2.33$ in the field around the $z=6.3$ quasar SDSSJ1030+0524. Using NIRCam images, we identified it as a bright outlier in the $F200W-F356W$ color vs $F356W$ magnitude …

Metallicity Scatter Originating from Subkiloparsec Starbursting Clumps in the Core of a Protocluster at z = 7.88

Takahiro Morishita, M. Stiavelli, E. Vanzella, P. Bergamini et autres

Abstract We present new JWST NIRSpec integral field unit (IFU) G395H/F290LP observations of a merging galaxy system at z = 7.88, part of A2744-z7p9OD, the most distant protocluster to date. The IFU cube reveals [O iii ] λ 5007 emissions in two …

The JWST View of Cygnus A: Jet-driven Coronal Outflow with a Twist

P. Ogle, Biny Sebastian, Archana Aravindan, M. McDonald et autres

Abstract We present first results from James Webb Space Telescope Near-Infrared Spectrograph, Mid-Infrared Instrument, and Keck Cosmic Webb Imager integral field spectroscopy of the powerful but highly obscured host galaxy of the jetted radio source Cygnus A. We detect 169 infrared emission …

What Can We Learn from the Nitrogen Abundance of High- z Galaxies?

M. Stiavelli, Takahiro Morishita, M. Chiaberge, Nicha Leethochawalit et autres

Abstract We present measurements of the gas-phase oxygen and nitrogen abundances obtained by applying the direct method to JWST NIRspec R ∼ 1000 spectroscopy for six galaxies at redshift greater than 3. Our measurements are based on rest-frame optical nitrogen [N ii …