Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
N. Leethochawalit
M. Trenti
P. Santini
L. Yang
E. Merlin
M. Castellano
A. Fontana
T. Treu
C. Mason
K. Glazebrook
T. Jones
B. Vulcani
T. Nanayakkara
D. Marchesini
S. Mascia
T. Morishita
G. Roberts-Borsani
A. Bonchi
D. Paris
K. Boyett
Abstract： We present the first James Webb Space Telescope/NIRCam-led determination of
$7
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Lilan Yang
T. Morishita
N. Leethochawalit
M. Castellano
A. Calabro
T. Treu
A. Bonchi
A. Fontana
C. Mason
E. Merlin
D. Paris
M. Trenti
G. Roberts-Borsani
M. Bradac
E. Vanzella
B. Vulcani
D. Marchesini
X. Ding
Themiya Nanayakkara
Simon Birrer
Abstract： We present the first rest-frame optical size-luminosity relation of galaxies
at $z>7$, using the NIRCam imaging data obtained by the GLASS James Webb Space
Telescope Early Release Science (GLASS-JWST-ERS) program, providing the deepest
extragalactic data of the ERS campaign. Our sample consist of 19
photometrically selected bright galaxies with $m_\text{F444W}\leq27.8$ at
$7
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
P. Santini
A. Fontana
M. Castellano
N. Leethochawalit
M. Trenti
T. Treu
D. Belfiori
S. Birrer
A. Bonchi
E. Merlin
C. Mason
T. Morishita
M. Nonino
D. Paris
G. Polenta
P. Rosati
L. Yang
M. Bradac
A. Calabrò
A. Dressler
Abstract： We exploit James Webb Space Telescope (JWST) NIRCam observations from the GLASS-JWST-Early Release Science program to investigate galaxy stellar masses at z>7. We first show that JWST observations reduce the uncertainties on the stellar mass by a factor of at least 5-10, when compared with the highest quality data sets available to date. We then study the UV mass-to-light ratio, finding that galaxies exhibit a two orders of magnitude range of M/L_UV values for a given luminosity, indicative of a broad variety of physical conditions and star formation histories. As a consequence, previous estimates of the cosmic star stellar mass density - based on an average correlation between UV luminosity and stellar mass - can be biased by as much as a factor of ~6. Our first exploration demonstrates that JWST represents a new era in our understanding of stellar masses at z>7, and therefore of the growth of galaxies prior to cosmic reionization.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
S. Mascia
L. Pentericci
A. Calabro'
T. Treu
P. Santini
L. Yang
L. Napolitano
G. Roberts-Borsani
P. Bergamini
C. Grillo
P. Rosati
B. Vulcani
M. Castellano
K. Boyett
A. Fontana
K. Glazebrook
A. Henry
C. Mason
E. Merlin
T. Morishita
Abstract： The escape fraction of Lyman-continuum (LyC) photons ($f_{esc}$) is a key parameter for determining the sources of cosmic reionization at $z\geq 6$. At these redshifts, owing to the opacity of the intergalactic medium, the LyC emission cannot be measured directly. However, LyC leakers during the epoch of reionization could be identified using indirect indicators that have been extensively tested at low and intermediate redshifts. These include a high [OIII]/[OII] flux ratio, high star-formation surface density, and compact sizes. In this work, we present observations of 29 $4.5 \leq z \leq 8$ gravitationally lensed galaxies in the Abell 2744 cluster field. From a combined analysis of JWST-NIRSpec and NIRCam data, we accurately derived their physical and spectroscopic properties: our galaxies have low masses $(\log(M_\star)\sim 8.5)$, blue UV spectral slopes ($\beta \sim -2.1$), compact sizes ($r_e \sim 0.3-0.5$ kpc), and high [OIII]/[OII] flux ratios. We confirm that these properties are similar to those characterizing low-redshift LyC leakers. Indirectly inferring the fraction of escaping ionizing photons, we find that more than 80% of our galaxies have predicted $f_{esc}$ values larger than 0.05, indicating that they would be considered leakers. The average predicted $f_{esc}$ value of our sample is 0.12, suggesting that similar galaxies at $z\geq 6$ have provided a substantial contribution to cosmic reionization.
Peer Review Status:Awaiting Review
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