A5069023402- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Scientific Research and Discoveries
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- Dark Matter and Cosmic Phenomena
- Phase Equilibria and Thermodynamics
- Neutrino Physics Research
- CCD and CMOS Imaging Sensors
- Historical Astronomy and Related Studies
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Historical and Architectural Studies
- Calibration and Measurement Techniques
- Mathematics and Applications
University of Toronto
2015-2024
Canadian Institute for Advanced Research
2015
Canada Research Chairs
2010
Dominion Astrophysical Observatory
2009
Cerro Tololo Inter-American Observatory
2008
Aix-Marseille Université
2007
Observatoire de Paris
2007
Centre National de la Recherche Scientifique
1998-2007
San Francisco State University
2002
Canada–France–Hawaii Telescope
1996-2001
Abstract The DESI Legacy Imaging Surveys ( http://legacysurvey.org/ ) are a combination of three public projects (the Dark Energy Camera Survey, the Beijing–Arizona Sky and Mayall z -band Survey) that will jointly image ≈14,000 deg 2 extragalactic sky visible from northern hemisphere in optical bands g , r using telescopes at Kitt Peak National Observatory Cerro Tololo Inter-American Observatory. combined survey footprint is split into two contiguous areas by Galactic plane. imaging...
We measure spectral indexes for 1823 galaxies in the Canadian Network Observational Cosmology 1 (CNOC1) sample of 15 X-ray luminous clusters at 0.18 < z 0.55 to investigate mechanisms responsible differential evolution between galaxy cluster and field environments. The radial trends D4000, W0(Hδ), W0(O ) are all consistent with an age sequence, sense that last episode star formation occurred more recently farthest from center. Throughout environment, show evidence older stellar populations...
We present observational constraints on the nature of dark energy using Supernova Legacy Survey three-year sample (SNLS3) Guy et al. and Conley use 472 Type Ia supernovae (SNe Ia) in this sample, accounting for recently discovered correlations between SN luminosity host galaxy properties, include effects all identified systematic uncertainties directly cosmological fits. Combining SNLS3 data with full WMAP7 power spectrum, Sloan Digital Sky luminous red a prior Hubble constant H0 from SHOES,...
(Abridged) Precision cosmology with Type Ia supernovae (SNe Ia) makes use of the fact that SN luminosities depend on their light-curve shapes and colours. Using Supernova Legacy Survey (SNLS) other data, we show there is an additional dependence global characteristics host galaxies: events same shape colour are, average, 0.08mag (~4.0sigma) brighter in massive galaxies (presumably metal-rich) low specific star-formation rates (sSFR). SNe a sSFR also have smaller slope ("beta") between...
ABSTRACT The Next Generation Virgo Cluster Survey (NGVS) is a program that uses the 1 deg 2 MegaCam instrument on Canada–France–Hawaii Telescope to carry out comprehensive optical imaging survey of cluster, from its core virial radius—covering total area 104 —in u * griz bandpasses. Thanks dedicated data acquisition strategy and processing pipeline, NGVS reaches point-source depth g ≈ 25.9 mag (10σ) surface brightness limit μ ∼ 29 arcsec −2 (2σ above mean sky level), thus superseding all...
view Abstract Citations (449) References (36) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spiral instabilities provoked by accretion and star formation Sellwood, J. A. ; Carlberg, R. G. A description of spiral structure is presented that appears to account for both the imperfect grand-design nature patterns importance gas. It argued most visible spirals are short-lived features organized gravitational forces. The recurrent transient self-regulating since...
(ABRIDGED) We show that Type Ia supernovae (SNe Ia) are formed within both very young and old stellar populations, with observed rates depend on the mass mean star-formation (SFRs) of their host galaxies. Models where SN rate depends solely galaxy ruled out 99% confidence. Our analysis is based 100 spectroscopically-confirmed SNe Ia, plus 24 photometrically-classified events, all from Supernova Legacy Survey (SNLS) distributed over 0.2
With the advent of large dedicated Type Ia supernova (SN Ia) surveys, K-corrections SNe and their uncertainties have become especially important in determination cosmological parameters. While are largely driven by SN broad-band colors, it is shown here that diversity spectral features can also be important. For an individual observation, statistical errors from inhomogeneity range 0.01 (where observed rest-frame filters aligned) to 0.04 misaligned). To minimize systematic caused assumed...
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 the Pristine survey, a new narrow-band photometric survey focused on metallicity-sensitive Ca H & K lines and conducted in northern hemisphere with wide-field imager MegaCam Canada-France-Hawaii Telescope (CFHT). This paper reviews our overall strategy discusses data processing metallicity calibration. Additionally we review application of these to main aims which are gather large sample most metal-poor stars Galaxy, further characterise faintest Milky Way satellites, map...
The Milky Way halo was predominantly formed by the merging of numerous progenitor galaxies. However, our knowledge this process is still incomplete, especially in regard to total number mergers, their global dynamical properties and contribution stellar population Galactic halo. Here, we uncover mergers detecting groupings globular clusters, streams satellite galaxies action ($\mathbf{J}$) space. While actions fully characterize orbits, additionally use redundant information on energy...
We examine the cosmic star formation rate (SFR) and its dependence on galaxy stellar mass over redshift range 0.8 < z 2 using data from Gemini Deep Survey (GDDS). The SFR in most massive galaxies (M > 10^{10.8} M_sun) was six times higher at = than it is today. It drops steeply 2, reaching present day value ~ 1. In contrast, density of intermediate (10^{10.2} M declines more slowly may peak or plateau 1.5. use characteristic growth time t_SFR rho_M / rho_SFR to provide evidence an...
The Gemini Deep Survey (GDDS) is an ultradeep (K < 20.6 mag, I 24.5 mag) redshift survey targeting galaxies in the "redshift desert" between z=1 and z=2. primary goal of to constrain space density at high evolved high-mass galaxies. We obtained 309 spectra four widely separated 30 arcmin2 fields using North telescope Multi-Object Spectrograph (GMOS). define a one-in-two sparse sample reddest most luminous near I-K versus color-magnitude track mapped out by passively evolving interval 0.8 z...
A comparison of star formation properties as a function environment is made from the spectra identically selected cluster and field galaxies in CNOC 1 redshift survey over 2000 fields 15 X-ray luminous clusters at 0.18 < z 0.55. The ratio bulge luminosity to total galaxy (B/T) computed for this sample, measure morphology compared with rate determined [O II] λ3727 emission line. mean brighter than Mr=-17.5+5logh found vary 0.17 ± 0.02 h-2 M☉ yr-1 R200 (1.5-2 h-1 Mpc) 0.00 0.01 center, it...
The average mass density profile measured in the Canadian Network for Observational Cosmology cluster survey is well described with analytic form ρ(r) = Ar-1(r + aρ)-2, as advocated on basis of n-body simulations by Navarro, Frenk, & White. predicted core radii are aρ 0.20 (in units radius where mean interior 200 times critical density) an Ω 0.2 open cold dark matter model and 0.26 a flat model, little dependence other cosmological parameters normalized to observed abundance. dynamically...
The rest-frame equivalent width of the [OII] λ3727 emission line, W0(O II), has been measured for cluster and field galaxies in Canadian Network Observational Cosmology redshift survey rich clusters at 0.2<z<0.55. Emission lines any strength all distances from center, out to 2R200, are less common than galaxies. mean II) more luminous Mkr < -18.5 + 5 log h (q0=0.1) is 3.8±0.3 Å (where uncertainty 1 σ error mean), which significantly galaxy 11.2±0.3 Å. For innermost members (R<0.3R200), only...
We examine the evolution of galaxy luminosity function (LF) using a sample over 2000 galaxies, with 0.12 < z 0.55 and 17.0 RC 21.5, drawn from Canadian Network for Observational Cosmology Field Galaxy Redshift Survey (CNOC2), at present largest such intermediate redshifts. use UBVRCIC photometry spectral energy distributions (SEDs) Coleman, Wu, Weedman to classify our galaxies into early, intermediate, late types, which we compute LFs in rest-frame B, RC, U bandpasses. In particular, adopt...
We present spectroscopic evidence from the Gemini Deep Survey for a significant population of color-selected red galaxies at 1.3 < z 2.2 whose integrated light is dominated by evolved stars. Unlike radio-selected objects, > 1.5 old have sky density greater than 0.1 arcmin-2. Conservative age estimates 20 with 1.3, ⟨z⟩ = 1.49, give median 1.2 Gyr and ⟨zf⟩ 2.4. One-quarter inferred zf 4. Models restricted to [Fe/H] ≤ 0 ages 2.3 3.3, respectively. These are among most massive contribute ~50%...
We present new techniques for improving the efficiency of supernova (SN) classification at high redshift using 64 candidates observed Gemini North and South during first year Supernova Legacy Survey (SNLS). The SNLS is an ongoing 5 project with goal measuring equation state dark energy by discovering following over 700 high-redshift SNe Ia data from Canada-France-Hawaii Telescope Survey. achieve improvement in SN spectroscopic confirmation rate: 71% are now confirmed as Ia, compared to 54%...
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...
We use Gaia DR2 astrometric and photometric data, published radial velocities MESA models to infer distances, orbits, surface gravities, effective temperatures for all ultra metal-poor stars ($\FeH<-4.0$ dex) available in the literature. Assuming that these are old ($>11\Gyr$) they expected belong Milky Way halo, we find 42 (18 dwarf 24 giants or sub-giants) currently within $\sim20\kpc$ of Sun map a wide variety orbits. A large fraction those remains confined inner parts halo was likely...
The orbits of the least chemically enriched stars open a window on formation our Galaxy when it was still in its infancy. common picture is that these low-metallicity are distributed as an isotropic, pressure-supported component since were either accreted from early building blocks assembling Milky Way, or later brought by accretion faint dwarf galaxies. Combining metallicities and radial velocities Pristine LAMOST surveys Gaia DR2 parallaxes proper motions for unprecedented large unbiased...