XMM-<i>Newton</i>observations of Extremely Red Objects and the link with luminous, X-ray obscured quasars

Brusa, M.; Comastri, A.; Daddi, E.; Pozzetti, L.; Zamorani, G.; Vignali, C.; Cimatti, A.; Fiore, F.; Mignoli, M.; Ciliegi, P.; Röttgering, H. J. A.

doi:10.1051/0004-6361:20041468

Cited by 92 publications

(118 citation statements)

References 62 publications

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“…In B10 we presented a sample of ∼ 170 obscured AGN isolated from the entire XMM-COSMOS sample, on the basis of their observed-frame mid-infrared (flux24µm/O> 1000), near-infrared (R-K> 5 or R-[3.6]> 4), optical and X-ray (X/O> 10) properties (following Fiore et al 2003;Brusa et al 2005;Mignoli et al 2004;Fiore et al 2009, Melini et al in preparation). We made use of the spectroscopic information and of the availability of spectral classifications, to assess the reliability of color cuts and flux ratios as diagnostics of the presence of obscured sources: of the 20 sources with optical spectra available, the vast majority (80%) are classified as narrow line AGN, and most of them are X-ray obscured (< HR >∼ −0.2, HR being defined as (H-S)/(H+S) where H and S are the counts in the 2-10 keV and 0.5-2 keV bands, respectively).…”

Section: Sample Selectionmentioning

confidence: 99%

X-shooter reveals powerful outflows in z ∼ 1.5 X-ray selected obscured quasi-stellar objects

Brusa

Bongiorno

Cresci

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We present X-shooter@VLT observations of a sample of 10 luminous, X-ray obscured QSOs at z∼ 1.5 from the XMM-COSMOS survey, expected to be caught in the transitioning phase from starburst to AGN dominated systems. The main selection criterion is X-ray detection at bright fluxes (L X > ∼ 10 44 erg s −1 ) coupled to red optical-to-NIR-to-MIR colors. Thanks to its large wavelength coverage, X-shooter allowed us to determine accurate redshifts from the presence of multiple emission lines for five out of six targets for which we had only a photometric redshift estimate, with a 80% success rate, significantly larger than what is observed in similar programs of spectroscopic follow-up of red QSOs. We report the detection of broad and shifted components in the [OIII]λλ5007,4959 complexes for 6 out of 8 sources with these lines observable in regions free from strong atmospheric absorptions. The FWHM associated with the broad components are in the range FWHM∼ 900 − 1600 km s −1 , larger than the average value observed in SDSS Type 2 AGN samples at similar observed [OIII] luminosity, but comparable to those observed for QSO/ULIRGs systems for which the presence of kpc scale outflows have been revealed through IFU spectroscopy. Although the total outflow energetics (inferred under reasonable assumptions) may be consistent with winds accelerated by stellar processes, we favour an AGN origin for the outflows given the high outflow velocities oberved (v> 1000 km s −1 ) and the presence of strong winds also in objects undetected in the far infrared.

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Section: Sample Selectionmentioning

confidence: 99%

X-shooter reveals powerful outflows in z ∼ 1.5 X-ray selected obscured quasi-stellar objects

Brusa

Bongiorno

Cresci

et al. 2014

Monthly Notices of the Royal Astronomical Society

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160

218

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“…Thus, an object that is optically faint while being infrared bright is a candidate hidden black hole. For instance, an oft-used diagnostic to identify red quasars is a color of R K -> 4-5 (Glikman et al 2004); this has been quite successful in identifying samples of reddened AGNs that are missed by optical-only surveys (e.g., Brusa et al 2005Brusa et al , 2015Glikman et al 2007Glikman et al , 2012Glikman et al , 2013Georgakakis et al 2009;Banerji et al 2012Banerji et al , 2015.…”

Section: Selecting Reddened Broad-lined Agnsmentioning

confidence: 99%

On R − W1 as a Diagnostic to Discover Obscured Active Galactic Nuclei in Wide-Area X-Ray Surveys

LaMassa

Civano

Brusa

et al. 2016

ApJ

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Capitalizing on the all-sky coverage of WISEand the 35% and 50% sky coverage from Sloan Digital Sky Survey and Pan-STARRS, respectively, we explore the efficacy of-, as a color diagnostic to identify obscured supermassive black hole accretion in wide-area X-ray surveys. We use the ∼16.5 deg 2 Stripe 82 X-ray survey data as a testbed to compare R W1 -with R−K, an oft-used obscured active galactic nucleus (AGN) selection criterion, and examine where different classes of objects lie in this parameter space. Most stars follow a well-defined path in R−K versus R W1space. We demonstrate that optically normal galaxies hosting X-ray AGNs at redshifts z 0.5 1 < < can be recovered with an R W1 4 -> colorcut, while they typically are not selected as AGNs based on their W W 1 2 -colors. Additionally, different observed X-ray luminosity bins favor different regions in R W1 -parameter space: moderate-luminosity AGNs > -erg s −1 ) have bluer colors; higher spectroscopic completeness of the Stripe 82X sample is needed to determine whether this is a selection effect or an intrinsic property. Finally, we parameterize X-ray obscuration of Stripe 82X AGNs by calculating their hardness ratios (HRs) and find no clear trends between HR and optical reddening. Our results will help inform best-effort practices in followingup obscured AGN candidates in current and future wide-area, shallow X-ray surveys, including the all-sky eROSITA mission.

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“…Among the hard X-ray objects (those which have a flux in the 2−10 keV band) we selected a subsample of sources with X-ray to optical ratio 12 X/O > 10. This characteristic indicator is important to identify highly obscured AGN/QSOs (see for example Fiore et al 2003;Mignoli et al 2004;Brusa et al 2005Brusa et al , 2010. Our sample consists of 252 highly obscured AGN/QSO candidates which represents 11% of the total AGN/QSO and 8% of the whole sample.…”

Section: X-ray and Multiwavelength Properties Of Selected Objectsmentioning

confidence: 99%

Classification and environmental properties of X-ray selected point-like sources in the XMM-LSS field

Мelnyk

Plionis

Elyiv

et al. 2013

A&A

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Context. The XMM-Large Scale Structure survey, covering an area of 11.1 sq. deg., contains more than 6000 X-ray point-like sources detected with the XMM-Newton to a flux of 3 × 10 −15 erg s −1 cm −2 in the [0.5−2] keV band. The vast majority of these sources have optical (CFHTLS), infrared (SWIRE IRAC and MIPS), near-infrared (UKIDSS), and/or ultraviolet (GALEX) counterparts. Aims. We wish to investigate the environmental properties of the different types of the XMM-LSS X-ray sources by defining their environment using the i -band CFHTLS W1 catalog of optical galaxies to a magnitude limit of 23.5 mag. Methods. We have classified 4435 X-ray selected sources on the basis of their spectra, SEDs, and X-ray luminosity, and estimated their photometric redshifts, which have a 4−11 band photometry with an accuracy of σ z/(1+zsp) = 0.076 with 22.6% outliers for i < 26 mag. We estimated the local overdensities of 777 X-ray sources that have spectro-z or photo-z calculated by using more than seven bands (accuracy of σ z/(1+zsp) = 0.061 with 13.8% outliers) within the volume-limited region defined by 0.1 ≤ z ≤ 0.85 and −23.5 < M i < −20. Results. Although X-ray sources may be found in variety of environments, a high fraction ( > ∼ 55−60%), as verified by comparing with the random expectations, reside in overdense regions. The galaxy overdensities within which X-ray sources reside show a positive recent redshift evolution (at least for the range studied; z < ∼ 0.85). We also find that X-ray selected galaxies, when compared to AGN, inhabit significantly higher galaxy overdensities, although their spatial extent appear to be smaller than that of AGN. Hard AGN (HR ≥ −0.2) are located in more overdense regions than soft AGN (HR < −0.2), which is clearly seen in both redshift ranges, although it appears to be stronger in the higher redshift range (0.55 < z < 0.85). Furthermore, the galaxy overdensities (with δ > ∼ 1.5) within which soft AGN are embedded appear to evolve more rapidly compared to the corresponding overdensities around hard AGN.

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XMM-Newtonobservations of Extremely Red Objects and the link with luminous, X-ray obscured quasars

Cited by 92 publications

References 62 publications

X-shooter reveals powerful outflows in z ∼ 1.5 X-ray selected obscured quasi-stellar objects

X-shooter reveals powerful outflows in z ∼ 1.5 X-ray selected obscured quasi-stellar objects

On R − W1 as a Diagnostic to Discover Obscured Active Galactic Nuclei in Wide-Area X-Ray Surveys

Classification and environmental properties of X-ray selected point-like sources in the XMM-LSS field

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