XBootes: An X‐Ray Survey of the NDWFS Bootes Field. I. Overview and Initial Results

Murray, Stephen S.; Kenter, A.; Forman, W.; Jones, Christine; Green, Paul; Kochanek, C. S.; Vikhlinin, A.; Fabricant, Daniel G.; Fazio, G. G.; Brand, Kate; Brown, M. J. I.; Dey, Arjun; Jannuzi, Buell T.; Najita, J.; McNamara, B. R.; Shields, J. C.; Rieke, M. J.

doi:10.1086/444378

Cited by 153 publications

(108 citation statements)

References 29 publications

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“…The authors base their estimate M BH on the L B,bul − M BH relation after estimating the bulge luminosity of the host galaxy in the B band, while the bolometric luminosity for X-ray AGN are derived from the bolometric correction of Hopkins et al (2007); for radio AGNs that are not detected in X-rays, they used the X-ray stacking results to derive approximate upper limits on the X-ray AGN luminosity, while for IR AGNs that are not detected in X-rays, L bol is derived from the rest-frame 4.5 µm luminosity. We also compare this with data from Kollmeier et al (2006), derived from the AGES survey and consisting of X-ray (XBootes survey, Murray et al 2005 or mid-infrared (Eisenhardt et al 2004) point sources with optical magnitude R ≤ 21.5 mag and optical emission-line spectra characteristic of AGNs. Black hole masses were estimated using virial relationships and Hβ MgII, and CIV emission-line widths, while bolometric luminosities were estimated using the bolometric correction of Kaspi et al (2000) to the monochromatic luminosities at 5100 Å.…”

Section: The Distributions Of the Eddington Ratiomentioning

confidence: 99%

Triggering active galactic nuclei in hierarchical galaxy formation: disk instability vs. interactions

Menci

Gatti

Fiore

et al. 2014

A&A

141

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Using a state-of-the-art semi analytic model for galaxy formation, we investigated in detail the effects of black hole (BH) accretion triggered by disk instabilities (DI) in isolated galaxies on the evolution of the AGN population. Specifically, we took on, developed, and expanded the Hopkins & Quataert (2011, MNRAS, 411, 1027 model for the mass inflow following disk perturbations, based on a physical description of nuclear inflows and tested against aimed N-body simulations. We compared the evolution of AGN due to such a DI accretion mode with that arising in a scenario where galaxy interactions (IT mode) produce the sudden destabilization of large quantities of gas feeding the AGN; this constitutes the standard AGN feeding mode implemented in the earliest versions of most semi-analytic models. To study the maximal contribution of DI to the evolution of the AGN population, we extended and developed the DI model to assess the effects of changing the assumed disk surface density profile, and to obtain lower limits for the nuclear star formation rates associated to the DI accretion mode. We obtained the following results: i) For AGN with luminosity M 1450 > ∼ −26, the DI mode can provide the BH accretion needed to match the observed AGN luminosity functions up to z ≈ 4.5. In such a luminosity range and redshift, it constitutes a viable candidate mechanism to fuel AGN, and can compete with the IT scenario as the main driver of cosmological evolution of the AGN population. ii) The DI scenario cannot provide the observed abundance of high-luminosity QSO with M 1450 ≤ −26 AGN, as well as the abundance of high-redhshift z > ∼ 4.5 QSO with M 1450 ≤ −24. As found in our earliest works, the IT scenario provides an acceptable match to the observed luminosity functions up to z ≈ 6. iii) The dispersion of the distributions of Eddington ratio λ for low-and intermediate-luminosity AGN (bolometric L AGN = 10 43 −10 45 erg s −1 ) is predicted to be much smaller in the DI scenario compared to the IT mode. iv) The above conclusions concerning the DI mode are robust with respect to the explored variants of the DI model. We discuss the physical origin of our findings. Finally, we discuss how it is possible to pin down the dominant fueling mechanism of AGN in the low-intermediate luminosity range M 1450 > ∼ −26 where the DI and the IT modes are both viable candidates as the main drivers of the AGN evolution. We show that an interesting discriminant could be provided by the fraction of AGN with high Eddington ratios λ ≥ 0.5, since it increases with luminosity in the IT case, while the opposite is true in the DI scenario.

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Section: The Distributions Of the Eddington Ratiomentioning

confidence: 99%

Triggering active galactic nuclei in hierarchical galaxy formation: disk instability vs. interactions

Menci

Gatti

Fiore

et al. 2014

A&A

141

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“…Moreover, the sky area covered by largest contiguous surveys did not exceed several (e.g. XMM-COSMOS: Hasinger et al 2007; XBootes: Murray et al 2005) to several tens of square degrees (e.g. XMM-LSS: Chiappetti et al 2012;XWAS: Esquej et al 2013;XXL: Pierre et al 2011), which in particular limited our knowledge of the evolution and clustering properties of the most luminous AGN severely.…”

Section: Introductionmentioning

confidence: 99%

AGN and QSOs in the eROSITA All-Sky Survey

Kolodzig

Gilfanov

Sunyaev

et al. 2013

A&A

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Context. The main element of the observing program of the Spectrum-Roentgen-Gamma orbital observatory is a four-year all-sky survey, in the course of which the entire sky will be scanned eight times. Aims. We analyze the statistical properties of active galactic nuclei (AGN) and quasars/quasi-stellar objects (QSOs ) that are expected to be detected in the course of the eROSITA all-sky survey (eRASS). Methods. According to the currently planned survey strategy and based on the parameters of the Galactic and extragalactic X-ray background as well as on the results of the recent calculations of the eROSITA instrumental background, we computed a sensitivity map of the eRASS. Using the best available redshift-dependent AGN X-ray luminosity function (XLF), we computed various characteristics of the eRASS AGN sample, such as their luminosity-and redshift distributions, and the brightness distributions of their optical counterparts. Results. After four years of the survey, a sky-average sensitivity of about 1 × 10 −14 erg s −1 cm −2 will be achieved in the 0.5−2.0 keV band. With this sensitivity, eROSITA is expected to detect about 3 million AGN on the extragalactic sky (|b| > 10 • ). The median redshift of the eRASS AGN will be z ≈ 1 with approximately 40% of the objects in the z = 1−2 redshift range. About 10 4 −10 5 AGN are predicted beyond redshift z = 3 and about 2000−30 000 AGN beyond redshift z = 4, the exact numbers depend on the poorly known behavior of the AGN XLF in the high-redshift and high-luminosity regimes. Of the detected AGN, the brightest 10% will be detected with more than ≈38 counts per point-spread-function (half-energy width), while the faintest 10% will have fewer than ≈9 counts. The optical counterparts of approximately 95% of the AGN will be brighter than I AB = 22.5 mag. The planned scanning strategy will allow one to search for transient events on a timescale of half a year and a few hours with a 0.5−2.0 keV sensitivity of ≈2 × 10 −14 to ≈2 × 10 −13 erg s −1 cm −2 , respectively.

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“…Sources at these intermediate fluxes are responsible for a large fraction of the X-ray background as they sample the region around the break in the X-ray source counts Mateos et al 2008). A number of campaigns have been dedicated to the optical-to-radio characterization of X-ray sources selected at A&A 557, A123 (2013) different X-ray depths like the XBöotes survey (Murray et al 2005;Brand et al 2006), the Extended Groth strip Survey (EGS Georgakakis et al 2006), the HELLAS2XMM survey (Cocchia et al 2007;Fiore et al 2003), the XMM-Newton and Chandra surveys in the COSMOS field Elvis et al 2009;Brusa et al 2010), and the Bright Ultra-Hard XMM-Newton Survey (BUXS; Mateos et al 2012).…”

Section: Introductionmentioning

confidence: 99%

TheXMM-NewtonWide Angle Survey (XWAS)

Esquej

Page

Carrera

et al. 2013

A&A

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Aims. This programme is aimed at obtaining one of the largest X-ray selected samples of identified active galactic nuclei to date in order to characterise such a population at intermediate fluxes, where most of the Universe's accretion power originates. We present the XMM-Newton Wide Angle Survey (XWAS), a new catalogue of almost a thousand X-ray sources spectroscopically identified through optical observations. Methods. A sample of X-ray sources detected in 68 XMM-Newton pointed observations was selected for optical multi-fibre spectroscopy. Optical counterparts and corresponding photometry of the X-ray sources were obtained from the SuperCOSMOS Sky Survey. Candidates for spectroscopy were initially selected with magnitudes down to R ∼ 21, with preference for X-ray sources having a flux F 0.5−4.5 keV ≥ 10 −14 erg s −1 cm −2 . Optical spectroscopic observations were made using the Two Degree Field of the Anglo Australian Telescope, and the resulting spectra were classified based on optical emission lines. Results. We have identified through optical spectroscopy 940 X-ray sources over Ω ∼ 11.8 deg 2 of the sky. Source populations in our sample can be summarised as 65% broad line active galactic nuclei (BLAGN), 16% narrow emission line galaxies (NELGs), 6% absorption line galaxies (ALGs) and 13% stars. An active nucleus is also likely to be present in the large majority of the X-ray sources spectroscopically classified as NELGs or ALGs. Sources lie in high-galactic latitude (|b| > 20 deg) XMM-Newton fields mainly in the southern hemisphere. Owing to the large parameter space in redshift (0 ≤ z ≤ 4.25) and flux (10 −15 ≤ F 0.5−4.5 keV ≤ 10 −12 erg s −1 cm −2 ) covered by the XWAS this work provides an excellent resource for the further study of subsamples and particular cases. The overall properties of the extragalactic objects are presented in this paper. These include the redshift and luminosity distributions, optical and X-ray colours and X-ray-to-optical flux ratios.

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XBootes: An X‐Ray Survey of the NDWFS Bootes Field. I. Overview and Initial Results

Cited by 153 publications

References 29 publications

Triggering active galactic nuclei in hierarchical galaxy formation: disk instability vs. interactions

Triggering active galactic nuclei in hierarchical galaxy formation: disk instability vs. interactions

AGN and QSOs in the eROSITA All-Sky Survey

TheXMM-NewtonWide Angle Survey (XWAS)

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