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Your search keyword '"G. Roberts-Borsani"' showing total 3 results
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3 results on '"G. Roberts-Borsani"'

1. Early Results from GLASS-JWST. VII. Evidence for Lensed, Gravitationally Bound Protoglobular Clusters at z = 4 in the Hubble Frontier Field A2744

Author

E. Vanzella, M. Castellano, P. Bergamini, T. Treu, A. Mercurio, C. Scarlata, P. Rosati, C. Grillo, A. Acebron, G. B. Caminha, M. Nonino, T. Nanayakkara, G. Roberts-Borsani, M. Bradac, X. Wang, G. Brammer, V. Strait, B. Vulcani, U. Meštrić, M. Meneghetti, F. Calura, Alaina Henry, A. Zanella, M. Trenti, K. Boyett, T. Morishita, A. Calabrò, K. Glazebrook, D. Marchesini, S. Birrer, L. Yang, and T. Jones

Subjects
II, ABELL-2744, STAR-FORMING CLUMPS, high-redshift galaxies, strong gravitational lensing, star clusters, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, EVOLUTION, GALAXIES, RESOLUTION, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract

We investigate the blue and optical rest-frame sizes (lambda~2300A-4000A) of three compact star-forming regions in a galaxy at z=4 strongly lensed (x30, x45, x100) by the Hubble Frontier Field galaxy cluster A2744 using GLASS-ERS JWST/NIRISS imaging at 1.15um, 1.50mu and 2.0mu with PSF < 0.1". In particular, the Balmer break is probed in detail for all multiply-imaged sources of the system. With ages of a few tens of Myr, stellar masses in the range (0.7-4.0) x 10^6 Msun and optical/ultraviolet effective radii spanning the interval 3 < R_eff < 20 pc, such objects are currently the highest redshift (spectroscopically-confirmed) gravitationally-bound young massive star clusters (YMCs), with stellar mass surface densities resembling those of local globular clusters. Optical (4000A, JWST-based) and ultraviolet (1600A, HST-based) sizes are fully compatible. The contribution to the ultraviolet underlying continuum emission (1600A) is ~30%, which decreases by a factor of two in the optical for two of the YMCs (~4000A rest-frame), reflecting the young ages (, 10 pages, 4 figures, 1 table. Submitted to ApJL

Published
2022
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2. Early Results from GLASS-JWST. VI. Extreme Rest-optical Equivalent Widths Detected in NIRISS Wide Field Slitless Spectroscopy

Author

K. Boyett, S. Mascia, L. Pentericci, N. Leethochawalit, M. Trenti, G. Brammer, G. Roberts-Borsani, V. Strait, T. Treu, M. Bradac, K. Glazebrook, A. Acebron, P. Bergamini, A. Calabrò, M. Castellano, A. Fontana, C. Grillo, A. Henry, T. Jones, D. Marchesini, C. Mason, A. Mercurio, T. Morishita, T. Nanayakkara, P. Rosati, C. Scarlata, E. Vanzella, B. Vulcani, X. Wang, and C. Willott

Subjects
SAMPLE, galaxy evolution, FOS: Physical sciences, Astronomy and Astrophysics, I, high-redshift galaxies, Astrophysics - Astrophysics of Galaxies, EVOLUTION, GALAXIES, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), O III EMITTERS, SURVEY DESIGN, EMISSION-LINE
Abstract

Wide Field Slitless Spectroscopy (WFSS) provides a powerful tool for detecting strong line emission in star forming galaxies (SFGs) without the need for target pre-selection. As part of the GLASS-JWST-ERS program, we leverage the near-infrared wavelength capabilities of NIRISS ($1-2.2\mu$m) to observe rest-optical emission lines out to $\rm{z}\sim 3.4$, to a depth and with a spatial resolution higher than ever before (H$\alpha$ to z750$A in our sample to be $12\%$. We determine a strong correlation between the measured H$\beta$ and [OIII]$\lambda5007$ EWs, supporting that the high [OIII]$\lambda5007$ EW objects require massive stars in young stellar populations to generate the high energy photons needed to doubly ionise oxygen. We extracted spectra for objects up to 2 mag fainter in the near-infrared than previous WFSS studies with the Hubble Space Telescope. Thus, this work clearly highlights the potential of JWST/NIRISS to provide high quality WFSS datasets in crowded cluster environments., Comment: 9 pages, 3 figures, submitted to APJL

Published
2022
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3. Newly Discovered Bright z ∼ 9–10 Galaxies and Improved Constraints on Their Prevalence Using the Full CANDELS Area.

Author

R. J. Bouwens, M. Stefanon, P. A. Oesch, G. D. Illingworth, T. Nanayakkara, G. Roberts-Borsani, I. Labbé, and R. Smit

Subjects
GALAXIES, SPACE telescopes, UNIVERSE, LUMINOSITY, DISEASE prevalence
Abstract

We report the results of an expanded search for z ∼ 9–10 candidates over the ∼883 arcmin2 CANDELS+ERS fields. This study adds 147 arcmin2 to the search area we consider over the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS) COSMOS, UDS, and EGS fields, while expanding our selection to include sources with bluer J125 − H160 colors than our previous J125 − H160 > 0.5 mag selection. In searching for new z ∼ 9–10 candidates, we make full use of all available Hubble Space Telescope (HST), Spitzer/IRAC, and ground-based imaging data. As a result of our expanded search and use of broader color criteria, three new candidate z ∼ 9–10 galaxies are identified. We also find again the z = 8.683 source previously confirmed by Zitrin et al. This brings our sample of probable z ∼ 9–11 galaxy candidates over the CANDELS+ERS fields to 19 sources in total, equivalent to one candidate per 47 arcmin2 (one per 10 WFC3/IR fields). To be comprehensive, we also discuss 28 mostly lower likelihood z ∼ 9–10 candidates, including some sources that seem to be reliably at z > 8 using the HST+IRAC data alone, but which the ground-based data show are much more likely at z < 4. One case example is a bright z ∼ 9.4 candidate, COS910-8, which seems instead to be at z ∼ 2. Based on this expanded sample, we obtain a more robust luminosity function (LF) at z ∼ 9 and improved constraints on the volume density of bright z ∼ 9 and z ∼ 10 galaxies. Our improved z ∼ 9–10 results again reinforce previous findings for strong evolution in the UV LF at z > 8, with a factor of ∼10 evolution seen in the luminosity density from z ∼ 10 to z ∼ 8. [ABSTRACT FROM AUTHOR]

Published
2019
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