PHOTOMETRIC REDSHIFT AND CLASSIFICATION FOR THE XMM–COSMOS SOURCES

By Mara Salvato, G. Hasinger, O. Ilbert, G. Zamorani, M. Brusa, N. Scoville, A. Rau, P. Capak, Stéphane Arnouts, H. Aussel and 33 more. 2008

268 citations recorded by the source corpus.

We present photometric redshifts and spectral energy distribution (SED) classifications for a sample of 1542 optically identified sources detected with XMM in the COSMOS field. Our template fitting classifies 46 sources as stars and 464 as nonactive galaxies, while the remaining 1032 require templates with an active galactic nucleus (AGN) contribution. High accuracy in the derived photometric redshifts was accomplished as the result of (1) photometry in up to 30 bands with high-significance detections, (2) a new set of SED templates, including 18 hybrids covering the far-UV to mid-infrared, which have been constructed by the combination of AGNs and nonactive galaxies templates, and (3) multiepoch observations that have been used to correct for variability (most important for type 1 AGNs). The reliability of the photometric redshifts is evaluated using the subsample of 442 sources with measured spectroscopic redshifts. We achieved an accuracy of for i*AB < 22.5 ( for i*AB < 24.5). The high accuracies were accomplished for both type 2 (where the SED is often dominated by the host galaxy) and type 1 AGNs and QSOs out to z = 4.5. The number of outliers is a large improvement over previous photometric redshift estimates for X-ray-selected sources (4.0% and 4.8% outliers for i*AB < 22.5 and i*AB < 24.5, respectively). We show that the intermediate band photometry is vital to achieving accurate photometric redshifts for AGNs, whereas the broad SED coverage provided by mid-infrared (Spitzer/IRAC) bands is important to reduce the number of outliers for normal galaxies.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/1a59bc366b118a655cbc53167036c2eab355f379

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS (2009, methodology): “Distribution of the photometric classification (see Table 2 in Salvato et al. 2009) for the spectroscopically identifiedType 1 AGN sample (hatched histogram), for the photometric sample (open histogram) and for the not-Type 1 AGN sample (filled histogram).”
Cosmic X-ray surveys of distant active galaxies (2015, background): “…X-ray sources such as AGN/galaxy hybrids, utilize dedicated sets of medium-band filters, and/or allow for AGN optical/NIR/MIR variability effects between different filters observed non-simultaneously (e.g., Salvato et al 2009; Cardamone et al 2010; Luo et al 2010; Xue et al 2012; Hsu et al 2014).”
The many flavours of photometric redshifts (2018, background): “The problems is alleviated in rich photometric datasets which are inclusive of both intermediate and narrow bands filters because they help to identify emission lines [78, 79, 110], which are the only feature visible in the power-law continuum of a QSO (bright AGN outshining their host) for which co”
Active galactic nuclei: what’s in a name? (2017, background): “…(Benitez et al. 2014) make use of the spectral features to not only identify AGN but to also estimate their (photometric) redshifts with a precision that reaches below 1% (e.g. Salvato et al. 2009; Hsu et al. 2014), a great improvement with respect to early attempts (Hatziminaoglou et al. 2000).”
THE zCOSMOS 10k-BRIGHT SPECTROSCOPIC SAMPLE (2009, methodology): “4 of the catalog, the newest photo-z of Ilbert et al. (2009) and Salvato et al. (2009) were used for the released version v3.”
ON THE COSMIC EVOLUTION OF THE SCALING RELATIONS BETWEEN BLACK HOLES AND THEIR HOST GALAXIES: BROAD-LINE ACTIVE GALACTIC NUCLEI IN THE zCOSMOS SURVEY (2009, methodology): “This has been studied in detail by Salvato et al. (2009), where it was demonstrated that correcting for even relatively small variation of the photometric points due to the non-simultaneous observation times can significantly improve the photometric redshift determination for AGN.”
THE STAR FORMATION HISTORY OF MASS-SELECTED GALAXIES IN THE COSMOS FIELD (2010, methodology): “Cross-matching the most recent XMM-COSMOS photo-z catalog (Salvato et al. 2009; Brusa et al. 2010) with the 3.6 µm selected parent sample delivered a total of 1,711 (i.e. ∼ 1”
The Herschel census of infrared SEDs through cosmic time (2013, methodology): “For the sources which host X-ray detected AGN, we substitute the Ilbert et al. redshift with a photometric redshift from Salvato et al. (2009, 2011).”
GALAXY STELLAR MASS ASSEMBLY BETWEEN 0.2 < z < 2 FROM THE S-COSMOS SURVEY (2009, background): “Like Capak et al. (2007), the galaxies with G > 0.43 were considered E/S0 galaxies.”
THE CHANDRA COSMOS SURVEY. III. OPTICAL AND INFRARED IDENTIFICATION OF X-RAY POINT SOURCES (2012, methodology): “The same catalog is used in Ilbertet al. (2009, 2010) and Salvato et al. (2009, 2011).”
IDENTIFYING LUMINOUS ACTIVE GALACTIC NUCLEI IN DEEP SURVEYS: REVISED IRAC SELECTION CRITERIA (2012, methodology): “Photometric redshifts for non X-ray sources are taken from Ilbert et al. (2009), whereas AGN-specific photometric redshifts for the XMM and Chandra samples were drawn from Salvato et al. (2009) and Salvato et al. (2011), respectively.”
DISSECTING PHOTOMETRIC REDSHIFT FOR ACTIVE GALACTIC NUCLEUS USING XMM- AND CHANDRA-COSMOS SAMPLES (2011, methodology): “In comparison with our previous analysis on the XMM-COSMOS sample (Salvato et al. 2009), we have shown that better results are obtained for faint, extended sources, that do not display optical variability, when a library of normal galaxies is used to fit their SED.”