A5057199104- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Astrophysics and Cosmic Phenomena
- Scientific Computing and Data Management
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Radio Astronomy Observations and Technology
- Remote Sensing in Agriculture
- Pulsars and Gravitational Waves Research
- Computational Physics and Python Applications
- Calibration and Measurement Techniques
- Spacecraft and Cryogenic Technologies
- Scientific Research and Discoveries
- Data Quality and Management
- CCD and CMOS Imaging Sensors
- Research Data Management Practices
- Advanced X-ray Imaging Techniques
- Solar and Space Plasma Dynamics
- Infrared Target Detection Methodologies
Western University
2015-2024
ORCID
2019
Center for Astrophysics Harvard & Smithsonian
2002-2011
University of Nottingham
2011
Harvard University Press
2004-2008
Harvard University
1998-2006
Smithsonian Astrophysical Observatory
2004
Herzberg Institute of Astrophysics
2001-2002
The Infrared Array Camera (IRAC) is one of three focal plane instruments in the Spitzer Space Telescope. IRAC a four-channel camera that obtains simultaneous broad-band images at 3.6, 4.5, 5.8, and 8.0 microns. Two nearly adjacent 5.2x5.2 arcmin fields view are viewed by four channels pairs (3.6 5.8 microns; 4.5 8 microns). All detector arrays 256x256 pixels size, with two shorter wavelength using InSb longer Si:As IBC detectors. powerful survey instrument because its high sensitivity, large...
We analyze star formation (SF) as a function of stellar mass (M*) and redshift z in the All-Wavelength Extended Groth Strip International Survey. For 2905 field galaxies, complete to 1010(1010.8) M☉ at < 0.7(1), with Keck spectroscopic redshifts out = 1.1, we compile SF rates (SFRs) from emission lines, GALEX, Spitzer MIPS 24 μm photometry, optical-NIR M* measurements, HST morphologies. Galaxies reliable signs form distinct "main sequence" (MS), limited range SFRs given (1 σ ≲ ±0.3 dex),...
Abstract The Astropy Project supports and fosters the development of open-source openly developed Python packages that provide commonly needed functionality to astronomical community. A key element is core package astropy , which serves as foundation for more specialized projects packages. In this article, we an overview organization project summarize features in package, recent major release, version 2.0. We then describe infrastructure designed facilitate support a broader ecosystem...
The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process galaxy evolution and γ-ray astronomy, but overall spectrum EBL between 0.1 1000 μm has never been determined directly from spectral energy distribution (SED) observations over a wide redshift range. evolving, derived here utilizing novel method based on only. This achieved observed rest-frame K-band luminosity function up to 4, combined with determination galaxy-SED-type fractions....
In this the first of a series Letters, we present panchromatic data set in Extended Groth Strip region sky. Our survey, All-Wavelength International Survey (AEGIS), aims to study physical properties and evolutionary processes galaxies at z ~ 1. It includes following deep, wide-field imaging sets: Chandra/ACIS X-ray, GALEX ultraviolet, CFHT/MegaCam Legacy optical, CFHT/CFH12K Hubble Space Telescope/ACS optical NICMOS near-infrared, Palomar/WIRC Spitzer/IRAC mid-infrared, Spitzer/MIPS...
We use a 24 μm-selected sample containing more than 8000 sources to study the evolution of star-forming galaxies in redshift range from z = 0 ~ 3. obtain photometric redshifts for most our survey using method based on empirically built templates spanning ultraviolet mid-infrared wavelengths. The accuracy these is better 10% 80% sample. derived distribution detected by peaks at around 0.6-1.0 (the location peak being affected cosmic variance) and decays monotonically 1 have fitted infrared...
The Infrared Array Camera (IRAC) on the Spitzer Space Telescope is absolutely calibrated by comparing photometry a set of A stars near north ecliptic pole to predictions based ground-based observations and stellar atmosphere model. brightness point sources an accuracy 3%, relative models for star atmospheres, performed analyzed in same manner as calibration stars. This includes corrections location array if centroid within peak pixel. Long-term stability IRAC was measured monitoring dwarfs K...
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part a continuing monitoring campaign at the Fred Lawrence Whipple Observatory Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is largest homogeneously reduced sample SNe date, nearly doubling number well-observed, nearby with published multicolor CCD light curves. large U-band unique addition, important connections high redshift. decline rate SN curves...
We present new observational determinations of the evolution 2-10keV X-ray luminosity function (XLF) AGN. utilise data from a number surveys including both 2Ms Chandra Deep Fields and AEGIS-X 200ks survey, enabling accurate measurements faint end XLF. combine direct, hard selection spectroscopic follow-up or photometric redshift estimates at z<1.2 with rest-frame UV colour pre-selection approach higher redshifts to avoid biases associated catastrophic failure redshifts. Only robust optical...
The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, Chandra Field South, COSMOS, Hubble North, and Groth Strip. SEDS covers total area of 1.46 deg2 to depth 26 AB mag (3σ) in both warm Infrared Array Camera (IRAC) bands at 3.6 4.5 μm. Because its uniform coverage so many widely-separated fields, subject roughly 25% smaller errors due cosmic variance than single-field same size. was designed...
We present deep 3.6-8 μm imaging of the Hubble Deep Field-South with Infrared Array Camera (IRAC) on Spitzer Space Telescope. study distant red galaxies (DRGs) at z > 2 selected by Js-Ks 2.3 and compare them a sample Lyman break (LBGs) = 2-3. The observed UV-to-8 spectral energy distributions are fitted stellar population models to constrain star formation histories derive masses. find that 70% DRGs best described dust-reddened star-forming 30% very well old "dead" models. Using only I-Ks...
We present a new catalog of photometric and spectroscopic data on M31 globular clusters (GCs). The includes optical near-infrared photometry for substantial fraction the 435 cluster candidates. use these to determine reddening intrinsic colors individual clusters, we find that extinction laws in Galaxy are not significantly different. There significant (up 0.2 mag V-K) offsets between clusters' simple stellar population predicted by synthesis models; suggest due systematic errors models....
We present the broad-band UV through mid-infrared spectral energy distributions (SEDs) of a sample 72 spectroscopically-confirmed star-forming galaxies at z=2.30+/-0.3. Located in arcmin-squared field centered on bright background QSO, HS1700+643, these were pre-selected to lie z~2 based solely their rest-frame colors and luminosities, should be representative UV-selected samples high redshift. In addition deep ground-based photometry spanning from 0.35-2.15 microns, we make use Spitzer/IRAC...
Infrared source counts at wavelengths 3 < lambda 10 um cover more than magnitudes in brightness, four orders of magnitude surface density, and reach an integrated density 10^5 sources/deg^2. At m<14 mag, most the sources are Galactic stars, agreement with models. After removal galaxy consistent what few measurements exist nearby wavelengths. 3.6 4.5 um, follow expectations a Euclidean world model down to ~16 mag drop below curve for fainter magnitudes. Counts these begin show decreasing...
We have identified 335 galaxy cluster and group candidates, 106 of which are at z > 1, using a 4.5 um selected sample objects from 7.25 deg^2 region in the Spitzer Infrared Array Camera (IRAC) Shallow Survey. Clusters were as 3-dimensional overdensities wavelet algorithm, based on photometric redshift probability distributions derived IRAC NOAO Deep Wide-Field Survey data. estimate only ~10% detections spurious. To date 12 1 candidates been confirmed spectroscopically, redshifts 1.06 to...
We investigate the nature of a sample 92 Spitzer/MIPS 24 micron selected galaxies in CDFS, showing power law-like emission Spitzer/IRAC 3.6-8 bands. The main goal is to determine whether not detected X-rays (47% sample) are part hypothetical population obscured AGN even deep X-ray surveys. majority IR power-law ULIRGs at z>1, and those with LIRG-like luminosities usually X-rays. optical spectral energy distributions (SEDs) almost equally divided between BLAGN SED class (similar an...
The Infrared Array Camera (IRAC) shallow survey covers 8.5 deg2 in the NOAO Deep Wide-Field Survey Boötes with three or more 30 s exposures per position. An overview of design, reduction, calibration, star-galaxy separation, and initial results is provided. includes ≈370,000, 280,000, 38,000, 34,000 sources brighter than 5 σ limits 6.4, 8.8, 51, 50 μJy at 3.6, 4.5, 5.8, 8 μm, respectively, including some unusual spectral energy distributions.
We present the AEGIS-X survey, a series of deep Chandra ACIS-I observations Extended Groth Strip. The survey comprises pointings at eight separate positions, each with nominal exposure 200 ks, covering total area approximately 0.67 deg2 in strip length 2 degrees. describe detail an updated version our data reduction and point-source-detection algorithms used to analyze these data. A 1325 band-merged sources have been found Poisson probability limit 4 × 10−6, limiting fluxes 5.3 10−17 erg cm2...
New images of M31 at 24, 70, and 160 μm taken with the Multiband Imaging Photometer for Spitzer (MIPS) reveal morphology dust in this galaxy. This is well represented by a composite two logarithmic spiral arms circular ring (radius ~10 kpc) star formation offset from nucleus. The appear to start ends bar nuclear region extend beyond star-forming ring. As has been found previous work, are not continuous, but composed segments. very except near M32 where it splits. lack well-defined prominence...
The Pan-Andromeda Archaeological Survey is a survey of $>400$ square degrees centered on the Andromeda (M31) and Triangulum (M33) galaxies that has provided most extensive panorama $L_\star$ galaxy group to large projected galactocentric radii. Here, we collate summarise current status our knowledge substructures in stellar halo M31, discuss connections between these features. We estimate 13 distinctive were produced by at least 5 different accretion events, all last 3 or 4 Gyrs. suggest few...
The structures of globular clusters (GCs) reflect their dynamical states and past histories. High-resolution imaging allows the exploration morphologies in other galaxies. Surface brightness profiles from new Hubble Space Telescope observations 34 GCs M31 are presented, together with fits several different structural models to each cluster. appear be adequately fit by standard King do not obviously require alternate descriptions relatively stronger halos, such as needed many nearby derived...
We visually and quantitatively determine the host galaxy morphologies of 94 intermediate-redshift (0.2 ≤ z < 1.2) active galactic nuclei (AGNs), selected using Chandra X-ray data Spitzer mid-infrared in Extended Groth Strip. Using recently developed morphology measures, second-order moment brightest 20% a galaxy's flux (M20) Gini coefficient, we find that X-ray-selected AGNs mostly reside E/S0/Sa galaxies (53%), while IR-selected show no clear preference for morphology. AGN hosts are members...