A5024842870- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- CCD and CMOS Imaging Sensors
- Astronomical Observations and Instrumentation
- Advanced Vision and Imaging
- Superconducting and THz Device Technology
- Scientific Research and Discoveries
- Impact of Technology on Adolescents
- Mycorrhizal Fungi and Plant Interactions
- Plant Pathogens and Fungal Diseases
- Underwater Vehicles and Communication Systems
- Material Science and Thermodynamics
- Spectroscopy and Laser Applications
- Marine and fisheries research
- Plant-Microbe Interactions and Immunity
- Music History and Culture
- Marine Bivalve and Aquaculture Studies
- Advanced Optical Sensing Technologies
Arizona State University
2020-2024
Northeastern University
2022-2024
NOAA National Marine Fisheries Service Northeast Fisheries Science Center
2022
University of Southampton
2021
Vassar College
2017-2020
Kavli Institute for Particle Astrophysics and Cosmology
2019
Massachusetts Institute of Technology
2017-2019
Moscow Institute of Thermal Technology
2019
University of Toronto
2014-2018
McGill University
2007-2013
We evaluate the effects of environment and stellar mass on galaxy properties at 0.85 < z 1.20 using a 3.6um-selected spectroscopic sample 797 cluster field galaxies drawn from GCLASS survey. confirm that for with LogM* > 9.3 well-known correlations between such as star-forming fraction (f_SF), SFR, SSFR, D(4000), color are already in place ~ 1. separate by comparing quiescent fixed environment, mass. The SSFR is correlated mass; however, it independent environment. same trend exists D(4000)...
Using new and published data, we construct a sample of 160 brightest cluster galaxies (BCGs) spanning the redshift interval 0.03 < z 1.63. We use this sample, which covers 70% history universe, to measure growth in stellar mass BCGs after correcting for correlation between BCG it lives. find that increase by factor 1.8 z=0.9 z=0.2. Compared earlier works, our result is closer predictions semi-analytic models. However, at z=0.9, relative z=0.2, are still 1.5 more massive than these Star...
We investigate the velocity vs. position phase space of z ~ 1 cluster galaxies using a set 424 spectroscopic redshifts in 9 clusters drawn from GCLASS survey. Dividing galaxy population into three categories: quiescent, star-forming, and poststarburst, we find that these populations have distinct distributions space. Most striking are poststarburst galaxies, which commonly found at small clustercentric radii with high velocities, appear to trace coherent ``ring" Using several zoom...
We present an analysis of galaxies in groups and clusters at 0.8 < z 1.2, from the GCLASS GEEC2 spectroscopic surveys. compute a 'conversion fraction' fconvert that represents fraction were prematurely quenched by their environment. For massive galaxies, Mstar > 1010.3 M⊙, we find ∼ 0.4 ∼0.6 clusters, similar to comparable measurements = 0. This means time between first accretion into more halo final star formation quenching is tp 2 Gyr. substantially longer than estimated required for...
Environment is one of the primary drivers galaxy evolution; via multiple mechanisms, it can control critical process transforming galaxies from star forming to quiescent, commonly termed “quenching”. Despite its importance, however, we still do not have a clear view how environmentally-driven quenching proceeds even in most extreme environments: clusters and their progenitor proto-clusters. Recent advances infrared capabilities enabled transformative progress only identification these...
Recent independent results from numerical simulations and observations have shown that brightest cluster galaxies (BCGs) increased their stellar mass by a factor of almost two between z~0.9 z~0.2. The further suggest more than half this is accreted through major mergers. Using sample 18 distant galaxy clusters with over 600 spectroscopically confirmed members them, we search for observational evidence mergers do play significant role. We find merger rate 0.38 +/- 0.14 per Gyr at z~1. While...
We present the stellar mass functions (SMFs) of passive and star-forming galaxies with a limiting 1010.1M⊙ in four spectroscopically confirmed Spitzer Adaptation Red-sequence Cluster Survey (SpARCS) galaxy clusters at 1.37 <z< 1.63. The have 113 members combined, 8–45 each. construct Ks-band-selected photometric catalogs for each cluster an average 11 bands ranging from u to 8 μm. compare our field sample derived similar catalog UltraVISTA/COSMOS field. SMFs resemble those field, but signs...
We analyse the evolution of environmental quenching efficiency, fraction quenched cluster galaxies that would be star-forming if they were in field, as a function redshift 14 spectroscopically confirmed galaxy clusters with 0.87 < z 1.63 from Spitzer Adaptation Red-Sequence Cluster Survey (SpARCS). The are richest survey at each redshift. Passive fractions rise $42_{-13}^{+10}$\% ~ 1.6 to $80_{-9}^{+12}$\% 1.3 and $88_{-3}^{+4}$\% 1.1, outpacing change passive field. Environmental efficiency...
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 Gemini Observations Galaxies Rich Early Environments (GOGREEN) survey. Based on more than 500 hours Gemini/GMOS spectroscopy, deep multi-band photometry taken with a range observatories, we probe SMFs down to limit 10^9.7 Msun (10^9.5 for galaxies). At this early epoch, fraction is already highly elevated compared field same redshift. The quenched excess (QFE)...
We present the results of an MIPS-24 μm study brightest cluster galaxies (BCGs) 535 high-redshift galaxy clusters. The clusters are drawn from Spitzer Adaptation Red-Sequence Cluster Survey, which effectively provides a sample selected on total stellar mass, over 0.2 < z 1.8 within Wide-Area Infrared Extragalactic (SWIRE) Survey fields. Twenty percent, or 106 clusters, have spectroscopically confirmed redshifts, and rest redshifts estimated color their red sequence. A comparison with public...
Using a sample of 4 galaxy clusters at $1.35 < z 1.65$ and 10 $0.85 1.35$, we measure the environmental quenching timescale, $t_Q$, corresponding to time required after is accreted by cluster for it fully cease star formation. Cluster members are selected photometric-redshift criterion, categorized as star-forming, quiescent, or intermediate according their dust-corrected rest-frame colors magnitudes. We employ "delayed-then-rapid" model that relates simulated mass accretion rate observed...
We present results on the environmental dependence of star-forming galaxy main sequence in 11 cluster fields at $1.0 < z 1.5$ from Gemini Observations Galaxies Rich Early Environments Survey (GOGREEN) survey. use a homogeneously selected sample field and galaxies whose membership is derived dynamical analysis. Using [OII]-derived star formation rates (SFRs), we find that have suppressed SFRs fixed stellar mass comparison to their counterparts by factor 1.4 $\pm$ 0.1 ($\sim3.3\sigma$) across...
We present ALMA CO (2-1) detections in 11 gas-rich cluster galaxies at z~1.6, constituting the largest sample of molecular gas measurements z>1.5 clusters to date. The observations span three galaxy clusters, derived from Spitzer Adaptation Red-sequence Cluster Survey. augment >5sigma fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, place some first constraints on properties z~1.6 environments. measure sizable reservoirs 0.5-2x10^11 solar...
We have discovered an optically rich galaxy cluster at z=1.7089 with star formation occurring in close proximity to the central galaxy. The system, SpARCS104922.6+564032.5, was detected within Spitzer Adaptation of red-sequence Cluster Survey, (SpARCS), and confirmed through Keck-MOSFIRE spectroscopy. rest-frame optical richness Ngal(500kpc) = 30+/-8 implies a total halo mass, 500kpc, ~3.8+/-1.2 x 10^14 Msun, comparable other clusters or above this redshift. There is wealth ancillary data...
We describe a new Large Program in progress on the Gemini North and South telescopes: Observations of Galaxies Rich Early Environments (GOGREEN). This is an imaging deep spectroscopic survey 21 galaxy systems at $1<z<1.5$, selected to span factor $>10$ halo mass. The scientific objectives include measuring role environment evolution low-mass galaxies, dynamics stellar contents their host haloes. targets are from SpARCS, SPT, COSMOS SXDS surveys, be evolutionary counterparts today's clusters...
Minor mergers are thought to be responsible for the size growth of quiescent field galaxies with decreasing redshift. We test this hypothesis using cluster environment as a laboratory. Satellite in clusters move at high velocities, making between them rare. The stellar mass-size relation ten and is measured compared $z~\mathtt{\sim}~1$. Our sample contains 344 spectroscopically-confirmed members Gemini/GMOS 182 confirmed HST WFC3 G141 grism spectroscopy. On average, star-forming smaller than...
We present a five-band Herschel study (100-500um) of three galaxy clusters at z~1.2 from the Spitzer Adaptation Red-Sequence Cluster Survey (SpARCS). With sample 120 spectroscopically-confirmed cluster members, we investigate role environment on properties utilizing projected phase space (line-of-sight velocity versus clustercentric radius), which probes time-averaged density to has been exposed. divide galaxies into phase-space bins (r/r200) x (v/sigma_v), tracing sequence accretion...
We study the star formation histories (SFHs) and mass-weighted ages of 331 UVJ-selected quiescent galaxies in 11 galaxy clusters field at 1<z<1.5 from Gemini Observations Galaxies Rich Early ENvironments (GOGREEN) survey. determine SFHs individual by simultaneously fitting rest-frame optical spectroscopy broadband photometry to stellar population models. confirm that are consistent with more massive having on average earlier times. Comparing found those field, we find $M_\ast<10^{11.3}$...
We present an infrared study of a z=0.872 cluster, SpARCS J161314+564930, with the primary aim distinguishing dynamical histories spectroscopically confirmed star-forming members to assess role cluster environment. utilize deep MIPS imaging and mass-limited sample 85 spectroscopic identify 16 24um-bright sources within measure their 24um star formation rates (SFRs) down ~6 Msolar/year. Based on line-of-sight velocities stellar ages, appear be infalling population that was recently accreted...
We present an IR study of high-redshift galaxy clusters with the MIPS camera on Spitzer Space Telescope. Employing a sample 42 from RCS-1 over redshift range 0.3 < z 1.0 and spanning approximate in mass 10^{14-15} Msun, we show number IR-luminous galaxies above fixed luminosity 2x10^{11} Msun per unit cluster evolves as (1+z)^{5.1+/-1.9}. These results assume single star forming template; presence AGN, evolution their relative contribution to mid-IR emission, will alter overall counts rate...
Abstract We present the first spatially resolved observations of molecular gas in a sample cluster galaxies beyond z > 0.1. Using ALMA, we detect CO (2–1) eight ∼ 1.6 galaxies, all within single 70″ primary beam. The cluster, SpARCS-J0225, was discovered by Spitzer Adaptation Red-sequence Cluster Survey, and is replete with gas-rich close proximity, thus affording an efficient multiplexing strategy to amass distant clusters. Mapping out kinematic structure morphology on ∼3.5 kpc scales...
We present the first public data release of GOGREEN and GCLASS surveys galaxies in dense environments, spanning a redshift range $0.8<z<1.5$. The consist deep, multiwavelength photometry extensive Gemini GMOS spectroscopy 26 overdense systems ranging halo mass from small groups to most massive clusters. objective both projects was primarily understand how evolution is affected by their environment, determine physical processes that lead quenching star formation. There an emphasis on...
We present the results of a Spitzer/Herschel infrared photometric analysis largest (716) and highest-redshift (z=1.8) sample Brightest Cluster Galaxies (BCGs), those from Spitzer Adaptation Red-Sequence Survey (SpARCS). Given tension that exists between model predictions recent observations BCGs at z<2, we aim to uncover dominant physical mechanism(s) guiding stellar-mass buildup this special class galaxies, most massive in Universe uniquely residing centres galaxy clusters. Through...
Abstract The cluster environment has been shown to affect the molecular gas content of members, yet a complete understanding this often subtle effect hindered due lack detections over full parameter space galaxy star formation rates (SFRs) and stellar masses. Here, we stack CO(2–1) spectra z ∼ 1.6 galaxies explore average fractions both at lower mass (log( M * / ⊙ ) 9.6) further below star-forming main sequence (SFMS; ΔMS −0.9) than other literature studies; translates 3 σ limit ∼7 × 10 9...