A5037576210- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Plant Water Relations and Carbon Dynamics
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Radio Astronomy Observations and Technology
- Advanced Vision and Imaging
- Computer Graphics and Visualization Techniques
- Advanced Image Processing Techniques
- Statistical and numerical algorithms
- Geophysics and Gravity Measurements
- Optical Systems and Laser Technology
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Remote Sensing in Agriculture
- Infrared Target Detection Methodologies
- Inertial Sensor and Navigation
- Advanced Measurement and Detection Methods
Saint Mary's University
2018-2024
Center for Astrophysics Harvard & Smithsonian
2012-2019
St. Mary's University
2019
Harvard College Observatory
2016
Harvard University
2015
University of Toronto
2007-2012
Fleet Science Center
2006
Ben-Gurion University of the Negev
2005
Astronomical Observatory
2004
University of Novi Sad
2003
We present the results of Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) imaging a sample 19 high-mass passively evolving galaxies with 1.2 < z 2, taken primarily from Gemini Deep Survey (GDDS). Around 80% in our GDDS have spectra dominated by stars ages ≳1 Gyr. Our rest-frame R-band images show that most these objects compact regular morphologies which follow classical R1/4 law. These scatter along tight sequence size versus surface brightness parameter space defines Kormendy...
We present an analysis of the size growth seen in early-type galaxies over 10 Gyr cosmic time. Our is based on a homogeneous synthesis published data from 17 spectroscopic surveys observed at similar spatial resolution, augmented by new measurements for Gemini Deep Survey. In total, our sample contains structural 465 (mainly early-type) redshift range 0.2<z<2.7. The evolution passively-evolving this gradual and continuous, with no evidence end or change to process around z~1, as has been...
(abridged) DYNAMO is a multi-wavelength, spatially-resolved survey of local ($z \sim 0.1$) star-forming galaxies designed to study evolution through comparison with samples at z~2. Half the sample has integrated H-alpha luminosities >$10^{42}$ erg/s, typical lower limit for resolved spectroscopy The covers range in stellar mass ($10^9$-$10^{11}$ Msun) and star-formation rate (0.2-100 Msun/yr). In this first paper series, we present integral-field emission 67 galaxies. We infer gas fractions...
We present ∼100 pc resolution Hubble Space Telescope Hα images of 10 galaxies from the DYnamics Newly-Assembled Massive Objects (DYNAMO) survey low-z turbulent disc galaxies, and use these to undertake first detailed systematic study effects clump clustering on observations clumps in discs. In DYNAMO-HST sample, we measure diameters spanning range dclump ∼ 100–800 pc, individual star formation rates as high ∼5 M⊙ yr−1. DYNAMO have very SFR surface densities, ΣSFR 1 − 15 yr−1 kpc−2, × higher...
We present the galaxy size-mass ($R_{e}-M_{\ast}$) distributions using a stellar-mass complete sample of $\sim1.5$ million galaxies, covering $\sim100$ deg$^2$, with $\log(M_{\ast}/M_{\odot})>10.2~(9.2)$ over redshift range $0.2<z<1.0$ $(z<0.6)$ from second public data release Hyper Suprime-Cam Subaru Strategic Program. confirm that, at fixed and stellar mass $\log(M_{\ast}/M_{\odot})<11$, star-forming galaxies are on average larger than quiescent galaxies. The large accurate size...
ABSTRACT We analyse the size evolution of 16 000 star-forming galaxies (SFGs) and 5000 quiescent (QGs) with mass M* &gt; 109.5 M⊙ at 0.1 &lt; z 0.9 from COSMOS field using deep CLAUDS + HSC imaging in two rest-frame wavelengths, 3000 Å (UV light) (visible light). With half-light radius (Re) as proxy for size, SFGs characteristic M0 = 5 × 1010 grow by 20 per cent (30 cent) UV (visible) light since ∼ 1 strength their increases stellar mass. After accounting growth due to star...
Abstract The HectoMAP spectroscopic survey provides a unique mass-limited sample of more than 35,000 quiescent galaxies ( D n 4000 > 1.5) covering the redshift range 0.2 < z 0.6. We segregate in bins properties based on stellar mass, 4000, and to construct set high signal-to-noise spectra representing massive M * 10 ⊙ ) population at intermediate redshift. These high-quality summed enable full spectrum fitting related extraction average age metallicity. galaxy increases with central as...
We describe the hCOSMOS redshift survey of COSMOS field conducted with Hectospec spectrograph on MMT. In central 1~deg$^2$, hCOS20.6 subset is $>90\%$ complete to a limiting $r=20.6$. The includes 1701 new redshifts in field. also use total 4362 and remeasured objects derive age sensitive D$_n4000$ index over entire interval $0.001\lesssim z\lesssim0.6$. For $85\%$ quiescent galaxies hCOS20.6, we measure line-of-sight velocity dispersion. To explore potential uses this survey, combine...
We investigate the evolution of compact galaxy number density over redshift range . Our sample consists galaxies with secure spectroscopic redshifts observed in COSMOS field. With large uncertainties, trend is consistent a constant value interval estimates are similar to at for equivalently selected samples. Small variations abundance sources as function correspond known structures The constancy robust and insensitive compactness threshold or stellar mass (for ). To maintain any size growth...
We measure the stellar specific angular momentum jstar=Jstar/Mstar in four nearby (z~0.1) disk galaxies that have masses Mstar near break M* of galaxy mass function, but look like typical star-forming disks at z~2 terms their low stability (Q~1), clumpiness, high ionized gas dispersion (40-50 km/s), molecular fraction (20-30%) and rapid star formation (~20 Msun/yr). Combining high-resolution (Keck-OSIRIS) large-radius (Gemini-GMOS) spectroscopic maps, only available z, we discover these...
In this Letter, we report the discovery of CO fluxes, suggesting very high gas fractions in three disk galaxies seen nearby universe (z ∼ 0.1). These were investigated as part DYnamics Newly Assembled Massive Objects (DYNAMO) survey. High-resolution Hubble Space Telescope imaging these objects reveals presence large star forming clumps bodies galaxies, while spatially resolved spectroscopy redshifted Hα dispersion rotating disks. The internal dynamical state resembles that systems at much...
(Abridged) The Maunakea Spectroscopic Explorer (MSE) is an end-to-end science platform for the design, execution and scientific exploitation of spectroscopic surveys. It will unveil composition dynamics faint Universe impact nearly every field astrophysics across all spatial scales, from individual stars to largest scale structures in Universe. Major pillars program MSE include (i) ultimate Gaia follow-up facility understanding chemistry distant Milky Way, including outer disk stellar halo...
Interactions between galaxies leave distinguishable imprints in the form of tidal features which hold important clues about their mass assembly. Unfortunately, these structures are difficult to detect because they low surface brightness so deep observations needed. Upcoming surveys promise several orders magnitude increase depth and sky coverage, for automated methods feature detection will become mandatory. We test ability a convolutional neural network reproduce human visual...
We present a comprehensive study of disks around 81 young low-mass stars and brown dwarfs in the nearby ~2-Myr-old Chamaeleon I star-forming region. use mid-infrared photometry from Spitzer Space Telescope, supplemented by findings ground-based high-resolution optical spectroscopy adaptive optics imaging. derive disk fractions 52 (+/-6) % 58 (+6/-7) based on 8-micron 24-micron colour excesses, respectively, consistent with those reported for other clusters similar age. Within uncertainties,...
Massive compact systems at 0.2<z<0.6 are the missing link between predominantly population of massive quiescent galaxies high redshift and their analogs relics in local volume. The evolution number density these extreme objects over cosmic time is crucial constraining factor for models galaxy assembly. We select a large sample ~200 intermediate-redshift compacts from BOSS spectroscopic dataset by identifying point-like SDSS photometric sources with signatures evolved redshifted galaxies. A...
We use Hectospec mounted on the 6.5-meter MMT to carry out a redshift survey of red ($r-i>0.2$, $g-r>0.8$, $r<21.3$) galaxies in COSMOS field measure environments massive compact quiescent at intermediate redshift. The $>90\%$ complete magnitude limited includes redshifts for 1766 with $r < 20.8$ covering central square degree field; $65\%$ this sample are new. select based rest-frame $UVJ$ colors. When density distribution is sampled scale 2 Mpc inhabit systematically denser regions than...
We study the spatially resolved stellar kinematics of two star-forming galaxies at z = 0.1 from larger DYnamics Newly Assembled Massive Objects (DYNAMO) sample. These galaxies, which have been characterized by high levels star formation and large ionized gas velocity dispersions, are considered possible analogs to high-redshift clumpy disks. They were observed using GMOS instrument in integral field spectroscopy (IFS) mode Gemini Observatory with spectral resolution (R=5400, equivalent 24...
The physical mechanisms that link the termination of star formation in quiescent galaxies and evolution their baryonic components, stars, interstellar medium (ISM; dust, gas, metals) are poorly constrained beyond local Universe. In this work, we characterise dust content 545 observed at 0.1 < z 0.6 as part hCOSMOS spectroscopic redshift survey. This is, to date, largest sample intermediate redshifts for which stellar, metal abundances consistently estimated. We analyse how crucial markers...
We used 1697 clusters of galaxies from the TNG300-1 simulation (mass M 200 c > 10 14 ⊙ and redshift range 0.01 ≤ z 1.04) to explore physics cluster infall region. average radial velocity profile derived simulated galaxies, v rad ( r ), dispersion at each redshift, σ cluster-centric dynamical radii that characterize revisited turnaround radius, limiting outer radius region, where has a well-defined minimum. also explored two new characteristic radii: (i) point inflection ) lies within...
Recent deep Hubble Space Telescope WFC3 imaging suggests that a majority of compact quiescent massive galaxies at z~2 may contain disks. To investigate this claim, we have compared the ellipticity distribution 31 carefully selected high-redshift to set mass-selected and Sersic index distributions obtained from 2D structural fits ~40,000$ nearby Sloan Digital Sky Survey. A Kolmogorov-Smirnov test shows ellipticities for is consistent with similarly chosen sample early-type galaxies. However...
In this letter we study the mean sizes of Halpha clumps in turbulent disk galaxies relative to kinematics, gas fractions, and Toomre Q. We use 100~pc resolution HST images, IFU fractions a sample rare, nearby disks with properties closely matched z~1.5-2 main-sequence (the DYNAMO sample). find linear correlations normalized clump both fraction velocity dispersion-to-rotation ratio host galaxy. show that these are consistent predictions derived from model instabilities self-gravitating...
We present a comprehensive study of rotation, disk and accretion signatures for 144 T Tauri stars in the young (~2 Myr old) Chamaeleon I Taurus-Auriga star forming regions based on multi-epoch high-resolution optical spectra from Magellan Clay 6.5 m telescope supplemented by mid-infared photometry Spitzer Space Telescope. In contrast to previous studies Orion Nebula Cluster NGC 2264, we do not see clear signature braking Tau-Aur Cha I. find that both accretors non-accretors have similar...
HectoMAP is a dense redshift survey of 95,403 galaxies based primarily on MMT spectroscopy with median $z = 0.345$. The covers 54.64 square degrees in 1.5$^\circ$ wide strip across the northern sky centered at declination 43.25$^\circ$. We report redshift, spectral indicator D$_{n}$4000, and stellar mass. red selected 81\% complete for 55,962 $(g-r) > 1$ $r <20.5$; it 72\% 32,908 1$, $(r-i) 0.5$ $20.5 < r 21.3$. Comparison basis SDSS photometry HSC-SSP demonstrates that provides magnitude...
We used simulated cluster member galaxies from the TNG300-1 run of IllustrisTNG simulations to develop a technique for measuring galaxy mass accretion rate (MAR) that can be applied directly observations. analyzed 1318 clusters with M 200c > 10 14 ⊙ and 0.01 ≤ z 1.04. The MAR we derived is ratio between spherical shell located in infall region time infalling accrete onto virialized cluster. At fixed redshift, an approximately one order magnitude increase results comparable MAR. mass,...