Examinando por Autor "Forrest, Ben"

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    An Extremely Massive Quiescent Galaxy at z = 3.493: Evidence of Insufficiently Rapid Quenching Mechanisms in Theoretical Models
    (Institute of Physics Publishing, 2020-02) Forrest, Ben; Annunziatella, Marianna; Wilson, Gillian; Marchesini, Danilo; Muzzin, Adam; Cooper, M.C; Marsan, Cemile; McConachie, Ian; C. C. Chan, Jeffrey; Gomez, Percy; Kado-Fong, Erin; La Barbera, Francesco; Labbé, Ivo; Daniel, Langle -Vagle; Julie, Nantais; Nonino, Mario; Peña, Theodore; Saracco, Paolo; Mauro, Stefanon; Remco van der Burg, F.J
    We present spectra of the most massive quiescent galaxy yet spectroscopically confirmed at z > 3, verified via the detection of Balmer absorption features in the H- A nd K-bands of Keck/MOSFIRE. The spectra confirm a galaxy with no significant ongoing star formation, consistent with the lack of rest-frame UV flux and overall photometric spectral energy distribution. With a stellar mass of 3.1-0.2-+0.1× 10-11\,M at z = 3.493, this galaxy is nearly three times more massive than the highest redshift spectroscopically confirmed absorption-line-identified galaxy known. The star formation history of this quiescent galaxy implies that it formed >1000 M o yr-1 for almost 0.5 Gyr beginning at z ∼ 7.2, strongly suggestive that it is the descendant of massive dusty star-forming galaxies at 5 < z < 7 recently observed with ALMA. While galaxies with similarly extreme stellar masses are reproduced in some simulations at early times, such a lack of ongoing star formation is not seen there. This suggests the need for a quenching process that either starts earlier or is more rapid than that currently prescribed, challenging our current understanding of how ultra-massive galaxies form and evolve in the early universe. © 2020. The American Astronomical Society. All rights reserved.
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    The GOGREEN Survey: Evidence of an Excess of Quiescent Disks in Clusters at 1.0
    (IOP Publishing Ltd, 2021-10-10) Chan, Jeffrey C. C.; Wilson, Gillian; Balogh, Michael; Rudnick, Gregory; van der Burg, Remco F. J.; Muzzin, Adam; Webb, Kristi A.; Biviano, Andrea; Cerulo, Pierluigi; Cooper, M. C.; De Lucia, Gabriella; Demarco, Ricardo; Forrest, Ben; Jablonka, Pascale; Lidman, Chris; McGee, Sean L.; Nantais, Julie; Old, Lyndsay; Pintos-Castro, Irene; Poggianti, Bianca; Reeves, Andrew M. M.; Vulcani, Benedetta; Yee, Howard K. C.; Zaritsky, Dennis
    We present the results of the measured shapes of 832 galaxies in 11 galaxy clusters at 1.0 < z < 1.4 from the GOGREEN survey. We measure the axis ratio (q), the ratio of the minor to the major axis, of the cluster galaxies from near-infrared Hubble Space Telescope imaging using Sersic profile fitting and compare them with a field sample. We find that the median q of both star-forming and quiescent galaxies in clusters increases with stellar mass, similar to the field. Comparing the axis ratio distributions between clusters and the field in four mass bins, the distributions for star-forming galaxies in clusters are consistent with those in the field. Conversely, the distributions for quiescent galaxies in the two environments are distinct, most remarkably in where clusters show a flatter distribution, with an excess at low q. Modelling the distribution with oblate and triaxial components, we find that the cluster and field sample difference is consistent with an excess of flattened oblate quiescent galaxies in clusters. The oblate population contribution drops at high masses, resulting in a narrower q distribution in the massive population than at lower masses. Using a simple accretion model, we show that the observed q distributions and quenched fractions are consistent with a scenario where no morphological transformation occurs for the environmentally quenched population in the two intermediate-mass bins. Our results suggest that environmental quenching mechanism(s) likely produce a population that has a different morphological mix than those resulting from the dominant quenching mechanism in the field.
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    MAGAZ3NE: High Stellar Velocity Dispersions for Ultramassive Quiescent Galaxies at z ≳ 3* * The spectra presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.
    (Institute of Physics, 2022-10-01) Forrest, Ben; Wilson, Gillian; Muzzin, Adam; Marchesini, Danilo; Cooper, M.C.; Cemile Marsan, Z.; Annunziatella, Marianna; McConachie, Ian; Zaidi, Kumail; Gomez, Percy; Urbano Stawinski, Stephanie M.; Chang, Wenjun; Lucia, Gabriella de; Barbera, Francesco La; Lubin, Lori; Nantais, Julie; Peña, Theodore; Saracco, Paolo; Surace, Jason; Stefanon, Mauro
    In this work, we publish stellar velocity dispersions, sizes, and dynamical masses for eight ultramassive galaxies (UMGs; log ( M * / M ⊙ ) > 11), z ≳ 3) from the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) Survey, more than doubling the number of such galaxies with velocity dispersion measurements at this epoch. Using the deep Keck/MOSFIRE and Keck/NIRES spectroscopy of these objects in the H and K bandpasses, we obtain large velocity dispersions of ∼400 km s−1 for most of the objects, which are some of the highest stellar velocity dispersions measured and ∼40% larger than those measured for galaxies of similar mass at z ∼ 1.7. The sizes of these objects are also smaller by a factor of 1.5-3 compared to this same z ∼ 1.7 sample. We combine these large velocity dispersions and small sizes to obtain dynamical masses. The dynamical masses are similar to the stellar masses of these galaxies, consistent with a Chabrier initial mass function (IMF). Considered alongside previous studies of massive quiescent galaxies across 0.2 < z < 4.0, there is evidence for an evolution in the relation between the dynamical mass-stellar mass ratio and velocity dispersion as a function of redshift. This implies an IMF with fewer low-mass stars (e.g., Chabrier IMF) for massive quiescent galaxies at higher redshifts in conflict with the bottom-heavy IMF (e.g., Salpeter IMF) found in their likely z ∼ 0 descendants, though a number of alternative explanations such as a different dynamical structure or significant rotation are not ruled out. Similar to data at lower redshifts, we see evidence for an increase of IMF normalization with velocity dispersion, though the z ≳ 3 trend is steeper than that for z ∼ 0.2 early-type galaxies and offset to lower dynamical-to-stellar mass ratios. © 2022. The Author(s). Published by the American Astronomical Society.
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    The First Quenched Galaxies: When and How?
    (American Astronomical Society, 2024-05-01) Xie, Lizhi; De Lucia, Gabriella; Fontanot, Fabio; Hirschmann, Michaela; Bahé, Yannick M.; Balogh, Michael L.; Muzzin, Adam; Vulcani, Benedetta; Baxter, Devontae C.; Forrest, Ben; Wilson, Gillian; Rudnick, Gregory H.
    Many quiescent galaxies discovered in the early Universe by JWST raise fundamental questions on when and how these galaxies became and stayed quenched. Making use of the latest version of the semianalytic model GAEA that provides good agreement with the observed quenched fractions up to z ∼ 3, we make predictions for the expected fractions of quiescent galaxies up to z ∼ 7 and analyze the main quenching mechanism. We find that in a simulated box of 685 Mpc on a side, the first quenched massive (M ⋆ ∼ 1011 M ⊙), Milky Way-mass, and low-mass (M ⋆ ∼ 109.5 M ⊙) galaxies appear at z ∼ 4.5, z ∼ 6.2, and before z = 7, respectively. Most quenched galaxies identified at early redshifts remain quenched for more than 1 Gyr. Independently of galaxy stellar mass, the dominant quenching mechanism at high redshift is accretion disk feedback (quasar winds) from a central massive black hole, which is triggered by mergers in massive and Milky Way-mass galaxies and by disk instabilities in low-mass galaxies. Environmental stripping becomes increasingly more important at lower redshift.
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    The GOGREEN Survey: A deep stellar mass function of cluster galaxies at 1.0 < z < 1.4 and the complex nature of satellite quenching
    (EDP Sciences, 2020-06-01) van der Burg, Remco F. J.; Rudnick, Gregory; Balogh, Michael L.; Muzzin, Adam; Lidman, Chris; Old, Lyndsay J.; Shipley, Heath; Gilbank, David; McGee, Sean; Biviano, Andrea; Cerulo, Pierluigi; Chan, Jeffrey C. C.; Cooper, Michael; De Lucia, Gabriella; Demarco, Ricardo; Forrest, Ben; Gwyn, Stephen; Jablonka, Pascale; Kukstas, Egidijus; Marchesini, Danilo; Nantais, Julie; Noble, Allison; Pintos-Castro, Irene; Poggianti, Bianca; Reeves, Andrew M. M.; Stefanon, Mauro; Vulcani, Benedetta; Webb, Kristi; Wilson, Gillian; Yee, Howard; Zaritsky, Dennis
    We study the stellar mass functions (SMFs) of star-forming and quiescent galaxies in 11 galaxy clusters at 1.0 < z < 1.4 drawn from the Gemini Observations of Galaxies in Rich Early ENvironments (GOGREEN) survey. Based on more than 500 h of Gemini/GMOS spectroscopy and deep multi-band photometry taken with a range of observatories, we probe the SMFs down to a stellar mass limit of 109.7 M (109.5 M for star-forming galaxies). At this early epoch, the fraction of quiescent galaxies is already highly elevated in the clusters compared to the field at the same redshift. The quenched fraction excess (QFE) represents the fraction of galaxies that would be star-forming in the field but are quenched due to their environment. The QFE is strongly mass dependent, and increases from ∼30% at M? = 109.7 M to ∼80% at M? = 1011.0 M . Nonetheless, the shapes of the SMFs of the two individual galaxy types, star-forming and quiescent galaxies, are identical between cluster and field to high statistical precision. Nevertheless, along with the different quiescent fractions, the total galaxy SMF is also environmentally dependent, with a relative deficit of low-mass galaxies in the clusters. These results are in stark contrast with findings in the local Universe, and therefore require a substantially different quenching mode to operate at early times. We discuss these results in light of several popular quenching models.
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    The Massive Ancient Galaxies at z > 3 NEar-infrared (MAGAZ3NE) Survey: Confirmation of Extremely Rapid Star Formation and Quenching Timescales for Massive Galaxies in the Early Universe
    (IOP Publishing Ltd, 2020-11-01) Forrest, Ben; Cemile Marsan Z.; Annunziatella, Marianna; Wilson, Gillian; Muzzin, Adam; Marchesini, Danilo; Cooper M.C.; Chan, Jeffrey C.C.; McConachie, Ian; Gomez, Percy; Kado-Fong, Erin; Barbera, Francesco La; Lange-Vagle, Daniel; Nantais, Julie; Nonino, Mario; Saracco, Paolo; Stefanon, Mauro; van der Burg, Remco F.J.
    We present near-infrared spectroscopic confirmations of a sample of 16 photometrically selected galaxies with stellar Keck/MOSFIRE masses log(as M*part M*of ) > the 11 Massive at redshift Ancient z > 3 Galaxies from the At XMM-VIDEO z > 3 NEar-infrared and COSMOS-UltraVISTA (MAGAZ3NE) survey. fields Eight using of the ultramassive galaxies (UMGs) have specific star formation rates (sSFR) < 0.03 Gyr−1, with negligible emission lines. Another seven UMGs show emission lines consistent with active galactic nuclei and/or star formation, while only one UMG has sSFR > 1 Gyr−1. Model star formation histories of these galaxies describe systems that formed the majority of their stars in vigorous bursts of several hundred megayear duration around 4 < z < 6 during which hundreds to thousands of solar masses were formed per year. These formation ages of <1 Gyr prior to observation are consistent with ages derived from measurements of Dn(4000) and EW0(Hδ). Rapid quenching followed these bursty star-forming periods, generally occurring less than 350 Myr before observation, resulting in post-starburst SEDs and spectra for half the sample. The rapid formation timescales are consistent with the extreme star formation rates observed in 4 < z < 7 dusty starbursts observed with ALMA, suggesting that such dusty galaxies are progenitors of these UMGs. While such formation histories have been suggested in previous studies, the large sample introduced here presents the most compelling evidence yet that vigorous star formation followed by rapid quenching is almost certainly the norm for high-mass galaxies in the early universe. The UMGs presented here were selected to be brighter than Ks = 21.7, raising the intriguing possibility that even (fainter) older quiescent UMGs could exist at this epoch.