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author = "Barger, A. J."

Found 70 documents, displaying page 1 of 7

The OPTX Project IV: How Reliable is [OIII] as a Measure of AGN Activity?

Author(s) : Trouille, L. , Barger, A. J.
Description : We compare optical and hard X-ray identifications of AGNs using a uniformly selected (above a flux limit of f_2-8 keV = 3.5e-15 erg/cm2/s) and highly optically spectroscopically complete ( > 80% for f_2-8 keV > 1e-14 erg/cm2/s and > 60% below) 2-8 keV sample observed in three Chandra fields (CLANS...
Repository : arXiv
Language(s) : Undetermined

The Number Density of Intermediate and High Luminosity Active Galactic Nuclei at z~2-3

Author(s) : Barger, A. J. , Cowie, L. L.
Description : We use the combination of the 2 Ms Chandra X-ray image, new J and H band images, and the Spitzer IRAC and MIPS images of the Chandra Deep Field-North to obtain high spectroscopic and photometric redshift completeness of high and intermediate X-ray luminosity sources in the redshift interval z=2-3....
Repository : arXiv
Language(s) : Undetermined

The view of galaxy formation from Hawaii: Seeing the dark side of the universe

Author(s) : Cowie, L. L. , Barger, A. J.
Description : The strength of the submillimeter background light shows directly that much of the energy radiated by star formation and AGN is moved to far infrared wavelengths. However, it is only as this background at 850 microns has been resolved with direct submillimeter imaging that we have seen that it is ...
Repository : arXiv
Language(s) : Undetermined

An Integrated Picture of Star Formation, Metallicity Evolution, and Galactic Stellar Mass Assembly

Author(s) : Cowie, L. L. , Barger, A. J.
Description : We present an integrated study of star formation and galactic stellar mass assembly from z=0.05-1.5 and galactic metallicity evolution from z=0.05-0.9 using a very large and highly spectroscopically complete sample selected by rest-frame NIR bolometric flux in the GOODS-N. We assume a Salpeter IMF...
Repository : arXiv
Language(s) : Undetermined

Measuring the Sources of the Intergalactic Ionizing Flux

Description : We use a wide-field (0.9 square degree) X-ray sample with optical and GALEX ultraviolet observations to measure the contribution of Active Galactic Nuclei (AGNs) to the ionizing flux as a function of redshift. Our analysis shows that the AGN contribution to the metagalactic ionizing background pea...
Repository : arXiv
Language(s) : Undetermined

Active Galactic Nuclei Selected from GALEX Spectroscopy: The Ionizing Source Spectrum at z~1

Author(s) : Barger, A. J. , Cowie, L. L.
Description : We use a complete sample of Lya emission-line selected AGNs obtained from nine deep blank fields observed with the grism spectrographs on the Galaxy Evolution Explorer (GALEX) satellite to measure the normalization and spectral shape of the AGN contribution to the ionizing background (rest-frame w...
Repository : arXiv
Language(s) : Undetermined

The OPTX Project V: Identifying Distant AGNs

Description : The Baldwin, Phillips, and Terlevich emission-line ratio diagnostic ([OIII]/H{\beta} versus [NII]/H{\alpha}, hereafter BPT diagram) efficiently separates galaxies whose signal is dominated by star formation from those dominated by AGN activity (BPT-AGN). Yet this BPT diagram is limited to...
Repository : arXiv
Language(s) : Undetermined

The Faintest X-ray Sources from z=0-8

Description : We use the new 4 Ms exposure of the CDF-S field obtained with the Chandra X-ray satellite to investigate the properties of the faintest X-ray sources over a wide range of redshifts. We use an optimized averaging procedure to investigate the weighted mean X-ray fluxes of optically selected sources ...
Repository : arXiv
Language(s) : Undetermined

Mapping the Evolution of High Redshift Dusty Galaxies with Submillimeter Observations of a Radio-Selected Sample

Description : Direct submm imaging has recently revealed the 850-micron background to be mostly composed of a population of distant ultraluminous infrared galaxies, but identifying the optical/NIR counterparts to these sources has proved difficult due to the poor submm spatial resolution. However, the proportio...
Repository : arXiv
Language(s) : Undetermined

Faint Submillimeter Counts from Deep 850 Micron Observations of the Lensing Clusters A370, A851, and A2390

Description : We present deep 850 micron maps of three massive lensing clusters, A370, A851, and A2390, with well-constrained mass models. Our cluster exposure times are more than 2 to 5 times longer than any other published cluster field observations. We catalog the sources and determine the submillimeter numb...
Repository : arXiv
Language(s) : Undetermined

Found 70 documents, displaying page 1 of 7