D. Christopher Martin
A5037270981- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Photocathodes and Microchannel Plates
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- CCD and CMOS Imaging Sensors
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Solar and Space Plasma Dynamics
- Atmospheric Ozone and Climate
- Advanced Optical Sensing Technologies
- Calibration and Measurement Techniques
- History and Developments in Astronomy
- Scientific Research and Discoveries
- Remote Sensing in Agriculture
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Radiation Detection and Scintillator Technologies
- Radiation Effects in Electronics
- Plant Water Relations and Carbon Dynamics
California Institute of Technology
2015-2024
Universidad Nacional Autónoma de México
2014
JDSU (United States)
2003
Kirtland Air Force Base
1988
Texas State University
1988
U.S. National Science Foundation
1979
Glenn Research Center
1977
National Solar Observatory
1974
University of Surrey
1972
Cornell University
1935
We give an overview of the Galaxy Evolution Explorer (GALEX), a NASA Mission launched on April 28, 2003. GALEX is performing first space UV sky-survey, including imaging and grism surveys in two bands (1350-1750 Angstroms 1750-2750 Angstroms). The include all-sky survey (m[AB] ~ 20.5), medium 1000 square degrees 23), deep 100 25), nearby galaxy survey. Spectroscopic (R=100-200) are underway with various depths sky coverage. Many targets overlap existing or planned surveys. will use measured...
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),...
We measure star formation rates (SFRs) of ≈50,000 optically selected galaxies in the local universe (z ≈ 0.1)—from gas-rich dwarfs to massive ellipticals. obtain dust-corrected SFRs by fitting GALEX (ultraviolet) and SDSS photometry a library dust-attenuated population synthesis models. For star-forming galaxies, our UV-based compare remarkably well with those from SDSS-measured emission lines (Hα). Deviations perfect agreement are shown be due differences dust attenuation estimates. In...
We describe the calibration status and data products pertaining to GR2 GR3 releases of Galaxy Evolution Explorer (GALEX). These have identical pipeline calibrations that are significantly improved over GR1 release. GALEX continues survey sky in far-ultraviolet (FUV, ~154 nm) near-ultraviolet (NUV, ~232 bands, providing simultaneous imaging with a pair photon-counting, microchannel plate, delay line readout detectors. 1.25° field view detectors well suited ultraviolet observations because...
We present measurements of the baryon acoustic peak at redshifts z = 0.44, 0.6 and 0.73 in galaxy correlation function final dataset WiggleZ Dark Energy Survey. combine our with lower-redshift from 6-degree Field Galaxy Survey Sloan Digital Sky Survey, producing a stacked survey which statistical significance detection is 4.9-sigma relative to zero-baryon model no peak. fit cosmological models this combined oscillation (BAO) comprising six distance-redshift data points, compare results...
We present images, integrated photometry, and surface-brightness color profiles for a total of 1034 nearby galaxies recently observed by the Galaxy Evolution Explorer (GALEX) satellite in its far-ultraviolet (FUV; λeff = 1516 Å) near-ultraviolet (NUV; 2267 bands. Our catalog objects is derived primarily from GALEX Nearby Galaxies Survey (NGS) supplemented larger than 1' diameter serendipitously found these fields other exposures similar greater depth. The sample analyzed here adequately...
We perform a joint determination of the distance-redshift relation and cosmic expansion rate at redshifts z = 0.44, 0.6 0.73 by combining measurements baryon acoustic peak Alcock-Paczynski distortion from galaxy clustering in WiggleZ Dark Energy Survey, using large ensemble mock catalogues to calculate covariance between measurements.We find that D A (z) (1205 ± 114, 1380 95, 1534 107) Mpc H(z) (82.6 7.8, 87.9 6.1, 97.3 7.0) km s -1 these three redshifts.Further our results with other...
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...
The WiggleZ Dark Energy Survey is a survey of 240,000 emission line galaxies in the distant universe, measured with AAOmega spectrograph on 3.9-m Anglo-Australian Telescope (AAT). target are selected using ultraviolet photometry from GALEX satellite, flux limit NUV<22.8 mag. redshift range containing 90% 0.2<z<1.0. primary aim to precisely measure scale baryon acoustic oscillations (BAO) imprinted spatial distribution these at look-back times 4-8 Gyrs. Detailed forecasts indicate will BAO...
(Abridged) Far ultraviolet to far infrared images of the nearby galaxy NGC5194, from Spitzer, GALEX, Hubble Space Telescope and ground--based data, are used investigate local global star formation, impact dust extinction in HII-emitting knots. In IR/UV-UV color plane, NGC5194 HII knots show same trend observed for normal star-forming galaxies, having a much larger dispersion than starburst galaxies. We identify as due UV emission predominantly tracing evolved, non-ionizing stellar...
We have analyzed the bivariate distribution of galaxies as a function ultraviolet-optical colors and absolute magnitudes in local universe. The sample consists with redshifts optical photometry from Sloan Digital Sky Survey (SDSS) main galaxy matched detections near-ultraviolet (NUV) far-ultraviolet (FUV) bands Medium Imaging being carried out by Galaxy Evolution Explorer (GALEX) satellite. In (NUV − r)0.1 versus Mr,0.1 color-magnitude diagram, separate into two well-defined blue red...
We present precise measurements of the growth rate cosmic structure for redshift range 0.1 < z 0.9, using redshift-space distortions in galaxy power spectrum WiggleZ Dark Energy Survey. Our results, which have a precision around 10 per cent four independent bins, are well fitted by flat Λ cold dark matter (ΛCDM) cosmological model with density parameter Ωm= 0.27. analysis hence indicates that this provides self-consistent description through large-scale perturbations and homogeneous...
The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of sample shows that most sample's variations stem from two underlying components, one representative a galaxy with low infrared-to-ultraviolet ratio and high ratio. influence several parameters on is studied (e.g., optical morphology, disk inclination, far-infrared color, ultraviolet slope, star formation...
We have initiated a search for extended ultraviolet disk (XUV-disk) galaxies in the local universe. Here we compare GALEX UV and visible-NIR images of 189 nearby (D < 40 Mpc) S0-Sm included Atlas Nearby Galaxies present first catalog XUV-disk galaxies. find that are surprisingly common but varied relative (UV/optical) extent morphology. Type 1 objects (≳20% incidence) structured, UV-bright/optically faint emission features outer disk, beyond traditional star formation threshold. 2 (~10%...
We present significant improvements in cosmic distance measurements from the Wig-gleZ Dark Energy Survey, achieved by applying reconstruction of baryonic acoustic feature technique.We show using both data and simulations that technique can often be effective despite patchiness survey, edge effects shot-noise.We investigate three redshift bins range 0.2 < z 1, all find improvement after detection its usage as a standard ruler.We measure model independent measures D V r fid s /r 1716± 83 Mpc,...
This paper presents cosmological results from the final data release of WiggleZ Dark Energy Survey. We perform full analyses different models using power spectra measured at $z=0.22$, 0.41, 0.60, and 0.78, combined with other sets. The limiting factor in this analysis is theoretical modeling galaxy spectrum, including nonlinearities, bias, redshift-space distortions. In we assess several methods for testing them against Gigaparsec simulations (GiggleZ). fit a base set six parameters,...
We compare the dust attenuation properties of two samples galaxies purely selected in Galaxy Evolution Explorer (GALEX) near-ultraviolet band (NUV; 1750-2750 Å, λmean = 2310 Å) and far-infrared (FIR) at 60 μm. These are built using GALEX IRAS sky surveys over ~600 deg2. The NUV-selected sample contains 95 detected down to NUV 16 mag (AB system). Eighty-three this spiral or irregular, only them not FIR-selected is from PSCz survey, which complete 0.6 Jy. Among 163 sources, we select 118...
We have studied ~2100 early-type galaxies in the SDSS DR3 which been detected by GALEX Medium Imaging Survey (MIS), redshift range 0 < z 0.11. Combining UV photometry with corollary optical data from SDSS, we find that, at a 95% confidence level, least ~30% of this sample to colors consistent some recent star formation within last Gyr. In particular, an NUV − r color less than 5.5 are very likely experienced such formation, taking into account possibility contribution flux upturn phenomenon....
We use the UV-optical color magnitude diagram in combination with spectroscopic and photometric measurements derived from SDSS sample to measure distribution of galaxies local universe (z < 0.25) their physical properties as a function specific star formation rate (SFR/M⋆) stellar mass (M⋆). Throughout this study our emphasis is on off "star-forming sequence." discuss how characteristics along sequence are related scaling relations typically for different morphological types. find, among...
We present the results of a determination galaxy luminosity function at ultraviolet wavelengths redshifts z = 0.0-0.1 from Galaxy Evolution Explorer (GALEX) data. determined in GALEX far-UV and near-UV bands sample galaxies with UV magnitudes between 17 20 that are drawn total 56.73 deg2 fields overlapping bJ-selected Two-Degree Field Redshift Survey. The resulting functions fainter than previous estimates result densities 1025.55±0.12 1025.72±0.12 ergs s-1 Hz-1 Mpc-3 1530 2310 Å,...
We introduce a new quantity, the mass flux density of galaxies evolving from blue sequence to red sequence. propose simple technique for constraining this using volume corrected number in extinction-corrected UV-optical color magnitude distribution, stellar age indexes H-delta-a and D_n(4000), prescription spectral evolution quenched star formation history. exploit excellent separation sequences NUV-r band color-magnitude diagram. The final value we measure, 0.033 M_sun yr^-1 Mpc^-3, is...
We present the Pan-STARRS1 discovery of long-lived and blue transient PS1-11af, which was also detected by Galaxy Evolution Explorer with coordinated observations in near-ultraviolet (NUV) band. PS1-11af is associated nucleus an early type galaxy at redshift z = 0.4046 that exhibits no evidence for star formation or active galactic activity. Four epochs spectroscopy reveal a pair broad absorption features UV on otherwise featureless spectra. Despite superficial similarity these to P-Cygni...
We use GALEX near-UV (NUV) photometry of a sample early-type galaxies selected in the SDSS (Sloan Digital Sky Survey) to study UV color-magnitude relation (CMR). NUV − r color is an excellent tracer even small amounts (~1% mass fraction) recent (≲1 Gyr) star formation, and so CMR allows us effect environment on formation history. analyze volume-limited 839 visually inspected redshift range 0.05 < z 0.10 brighter than Mr –21.5 with any possible emission-line or radio-selected active galactic...
We derive a variety of physical parameters including star formation rates (SFRs), dust attenuation, and burst mass fractions for 6472 galaxies observed by the Galaxy Evolution Explorer (GALEX) present in Sloan Digital Sky Survey Data Release 1 (SDSS DR1) main spectroscopic sample. Parameters are estimated statistical way comparing each broadband spectral energy distribution (SED) (two GALEX five SDSS bands) with an extensive library model galaxy SEDs, which cover wide range histories include...