A Uv to Mid-Ir Study of Agn Selection

Chung, Sun Mi; Kochanek, C. S.; Assef, Roberto J.; Brown, M. J. I.; Stern, Daniel; Jannuzi, Buell T.; Gonzalez, Anthony H.; Hickox, Ryan C.; Moustakas, John

doi:10.1088/0004-637x/790/1/54

Cited by 44 publications

(92 citation statements)

References 77 publications

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“…We have found that the Chung et al (2014) and Brodwin et al (2006) photometric redshift catalogs are consistent within their stated errors for galaxies out to z = 1.5. For the purposes of this work, we limit our photometric redshift catalog to sources with 4.5 μm fluxes greater than 5.2 μJy (5σ).…”

Section: Photometric Redshiftssupporting

confidence: 66%

“…After removing stars and brown dwarfs, this catalog contains 281,779 sources. Chung et al (2014) reports photometric redshift uncertainties of σ/(1 + z) = 0.040 for galaxies and σ/(1 + z) = 0.169 for AGNs, with 5% outlier rejection. As their analysis only includes sources that were unambiguously galaxies or unambiguously AGNs as determined during the SED fitting, we further test the photometric redshift uncertainties in two ways.…”

Section: Photometric Redshiftsmentioning

confidence: 99%

“…The Contribution from AGN: F gal As described in Assef et al (2010) and Chung et al (2014), the AGN content of a source can be determined through SED fitting by measuring the contributions of the best-fit galaxy and AGN templates to the UV-MIR SED. Specifically, we quantify the ratio of the UV-MIR luminosity from best-fit galaxy templates to the total UV-MIR luminosity (galaxy+AGN templates): F gal ≡ L gal /L total , with F gal = 0.5 providing a useful dividing line between sources whose luminosity is primarily from an AGN ( F gal < 0.5) versus those whose luminosity is primarily provided by the (host) galaxy ( F gal > 0.5).…”

Section: Photometric Redshiftsmentioning

confidence: 99%

“…Probing near the peak of the dust emission of the spectral energy distribution (SED; 80-36 μm over z = 1-1.75) allows us to quantify robust dustobscured SFRs in cluster galaxies selected using spectroscopic and photometric redshifts. We further identify AGN emission in cluster galaxies through SED fitting (e.g., Assef et al 2010;Chung et al 2014) using extensive multi-wavelength photometry in the X-ray to the mid-infrared (MIR). This information is used to account for the contribution to the cluster SF from AGN host galaxies in our 11 clusters with PACS imaging and to examine the AGN fraction as a function of environment in ∼250 clusters from the ISCS/IDCS over the redshift range z = 0.5-2.…”

Section: Introductionmentioning

confidence: 99%

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STAR FORMATION AND AGN ACTIVITY IN GALAXY CLUSTERS FROM z = 1–2: A MULTI-WAVELENGTH ANALYSIS FEATURING HERSCHEL/PACS

Alberts

Pope

Brodwin

et al. 2016

ApJ

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117

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We present a detailed, multi-wavelength study of star formation (SF) and active galactic nucleus (AGN) activity in 11 near-infrared (IR) selected, spectroscopically confirmed massive (10 14 M e ) galaxy clusters at 1 < z < 1.75. Using new deep Herschel/PACS imaging, we characterize the optical to far-IR spectral energy distributions (SEDs) for IR-luminous cluster galaxies, finding that they can, on average, be well described by field galaxy templates. Identification and decomposition of AGNs through SED fittings allows us to include the contribution to cluster SF from AGN host galaxies. We quantify the star-forming fraction, dust-obscured SF rates (SFRs) and specific SFRs for cluster galaxies as a function of cluster-centric radius and redshift. In good agreement with previous studies, we find that SF in cluster galaxies at z  1.4 is largely consistent with field galaxies at similar epochs, indicating an era before significant quenching in the cluster cores (r < 0.5 Mpc). This is followed by a transition to lower SF activity as environmental quenching dominates by z ∼ 1. Enhanced SFRs are found in lower mass (   < < M M 10.1 log 10.8) cluster galaxies. We find significant variation in SF from cluster to cluster within our uniformly selected sample, indicating that caution should be taken when evaluating individual clusters. We examine AGNs in clusters from z = 0.5-2, finding an excess AGN fraction at z  1, suggesting environmental triggering of AGNs during this epoch. We argue that our results-a transition from field-like to quenched SF, enhanced SF in lower mass galaxies in the cluster cores, and excess AGNs-are consistent with a co-evolution between SF and AGNs in clusters and an increased merger rate in massive halos at high redshift.

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Section: Photometric Redshiftssupporting

confidence: 66%

Section: Photometric Redshiftsmentioning

confidence: 99%

Section: Photometric Redshiftsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

STAR FORMATION AND AGN ACTIVITY IN GALAXY CLUSTERS FROM z = 1–2: A MULTI-WAVELENGTH ANALYSIS FEATURING HERSCHEL/PACS

Alberts

Pope

Brodwin

et al. 2016

ApJ

Self Cite

117

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“…In addition to color and variability selection, more sophisticated selection methods have been developed, such as full multi-wavelength fitting of the spectral energy distribution (Chung et al 2014), kernel density estimation (Richards et al 2009), the likelihood method (Kirkpatrick et al 2011a), neural networks (Yèche et al 2010), and extreme deconvolution (Bovy et al 2011a). These statistical methods model the underlying flux distribution of quasars based on empirical data and then assign probabilities that sources are quasars.…”

Section: Introductionmentioning

confidence: 99%

A Study of Quasar Selection in the Supernova Fields of the Dark Energy Survey

Tie¹,

Martini²,

Mudd³

et al. 2017

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We present a study of quasar selection using the supernova fields of the Dark Energy Survey (DES). We used a quasar catalog from an overlapping portion of the SDSS Stripe 82 region to quantify the completeness and efficiency of selection methods involving color, probabilistic modeling, variability, and combinations of color/ probabilistic modeling with variability. In all cases, we considered only objects that appear as point sources in the DES images. We examine color selection methods based on the Wide-field Infrared Survey Explorer2 color, a mixture of WISE and DES colors (g − i andiW 1), and a mixture of Vista Hemisphere Survey and DES colors (g − i and i − K ). For probabilistic quasar selection, we used XDQSO, an algorithm that employs an empirical multi-wavelength flux model of quasars to assign quasar probabilities. Our variability selection uses the multi-band χ 2 -probability that sources are constant in the DES Year 1 griz-band light curves. The completeness and efficiency are calculated relative to an underlying sample of point sources that are detected in the required selection bands and pass our data quality and photometric error cuts. We conduct our analyses at two magnitude limits, i<19.8 mag and i<22 mag. For the subset of sources with W1 and W2 detections, the -W W 1 2 color or XDQSOz method combined with variability gives the highest completenesses of >85% for both i-band magnitude limits and efficiencies of >80% to the bright limit and >60% to the faint limit; however, the giW1 and giW1+variability methods give the highest quasar surface densities. The XDQSOz method and combinations of W1W2/giW1/XDQSOz with variability are among the better selection methods when both high completeness and high efficiency are desired. We also present the OzDES Quasar Catalog of 1263 spectroscopically confirmed quasars from three years of OzDES observation in the 30 deg 2 of the DES supernova fields. The catalog includes quasars with redshifts up to z∼4 and brighter than i = 22 mag, although the catalog is not complete up to this magnitude limit.

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