# | Author Last Name | Author First Name | Email Address | Institution | Title | Abstract | Presentation | Discussion | Splinter Session | Session |
1 | Carrera | Francisco J. | carreraf@ifca.unican.es | Instituto de Fisica de Cantabria (CSIC-UC), Spain | Obscured and unobscured growth of supermassive black holes from the XMM-Newton Medium sensitivity Survey | We report on the current status of the XMM-Newton Medium sensitivity Survey, where we have identified the sources responsible for 50% of the accretion history in the Universe. This sample outnumbers previous medium X-ray surveys. We will discuss source counts, angular clustering, identifications, and X-ray spectral properties. Unobscured objects still dominate at these fluxes, but obscured sources become increasingly important at fainter fluxes. The X-ray-to-Optical flux ratio appears to be a good (but not perfect) discriminant between obscured and unobscured objects. Preliminary results confirm the presence of Fe-K emission in the stacked X-ray spectra of obscured and unobscured AGN. | oral | Questions: - Relation between AGN and galaxy formation - Fraction of obscured/Compton thick AGN - Cosmological evolution of obscured/unobscured AGN Further surveys: - All sky in 2-10 keV Science/methods: - Statistical identifications Debated: - All of the above | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 |
2 | Civano | Francesca | francesca.civano@bo.astro.it | INAF--OAB & Bologna University | Multiwavelenght properties of elusive AGNs: X-EROs and XBONGs | Extensive programs of follow--up observations of sources detected in both deep and shallow X--ray survey (Chandra Deep Fields, HELLAS2XMM and COSMOS) have revealed a complex nature for the hard X--ray source population. The large database of these surveys offers a unique possibility to select statistically relevant samples of AGN characterized by extreme properties either in the X--rays or in the optical/near--infrared bands or boths, and to investigate their multiwavelength spectral energy distributions (SEDs). I will present the results of a multiwavelength study of X--ray sources selected on the basis of their extreme X-ray to optical properties, i.e. X-ray bright Optically Normal Galaxies (XBONGs) and X-ray emitting Extremely Red Objects (X-EROs). I will also discuss the results about the SED fitting and the morphological analysis of Quasar host galaxies for both classes of sources. | oral | | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: Cluster Formation and Evolution | 2 |
3 | Donley | Jennifer | jdonley@as.arizona.edu | University of Arizona | X-ray Properties of Spitzer-Selected AGN | Hard X-ray selection is generally considered the most efficient and complete way to select AGN. Even the deepest X-ray surveys, however, can miss heavily obscured AGN, which are predicted in significant numbers by models of the X-ray background. We present results of a Spitzer mid-infrared search for AGN in the Chandra Deep Field-North. Approximately 50% of the Spitzer-selected AGN are not readily detected in the X-ray, suggesting that they are either highly obscured or intrinsically X-ray weak. We discuss the properties of this AGN sample and its relation to the X-ray--selected population. | oral | | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 |
4 | Eckart | Megan | eckart@srl.caltech.edu | Caltech | Recent Results from the SEXSI Survey: Comparison of AGN Selected by Chandra and Spitzer | We present the mid-IR properties and SEDs of spectroscopically-confirmed hard X-ray sources from five moderately-deep (50 - 200 ks) Chandra fields. These sources, identified in the SEXSI (Serendipitous Extragalactic X-ray Source Identification) survey, include (1) X-ray luminous, narrow-lined quasars; (2) X-ray bright, optically-normal galaxies (sources which appear inactive at optical wavelengths but reveal the presence of an active nucleus at X-ray energies); and (3) optically-faint X-ray sources which currently lack spectroscopic classification and are likely to be either at high-redshift, or heavily-obscured. In addition, we investigate the X-ray properties of mid-IR-selected AGN by performing a stacking analysis of sources undetected in X-rays in the Spitzer fields. | oral | | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 |
5 | Forman | Willam | wrf9112@gmail.com | Smithsonian Astrophysical Observatory - CFA | XBONGS in the XBootes Field | X-ray Bright Optically Normal Galaxies (XBONGS) have X-ray luminosities characteristic of accretion onto a SMBH, but lack the optical emission lines generally expected for AGN. We have analyzed a sample of 258 XBONGS detected in the XBootes Survey using X-ray, optical, infrared and radio observations. We find that XBONGS are not a single class of object, but fall into four categories -- red early-type galaxies, blue ellipticals, spiral/irregular galaxies and galaxies with AGN colors. We compare the luminosities, colors, X-ray spectra, and Eddington ratios of the XBONGS with those of narrow and broad-line AGN. | oral | | Monday: 'Normal' Galaxies, Tuesday: Groups and Interactions | 2 |
6 | Frank | Stephan | frank@astronomy.ohio-state.edu | The Ohio State University, Department of Astronomy | The sources of the CFD-N - classification schemes, absorption estimates and broadband SEDs | We have developed a classification scheme for the sources of the CDF-N with known redshifts based upon the visual appearance of their broadband SEDs. The observed X-ray column density distribution for the complete sample of AGN shows a significant rise of the number of sources with N$_{H} > 10^{22.5}${} cm$^{-2}${} when we include objects fainter than f$_{0.5-8.0 keV} = 3.0 \times 10^{-15}$erg s$^{-1}${} cm$^{-2}$. We argue that the ratio of X-ray absorbed to unabsorbed AGN remains constant with redshift, but not with luminosity. The comparison of the X-ray column density estimates with N$_{H}${}, obtained by fits to the broadband NIR-UV SEDs, validates our classification scheme, and allows for placing constraints on unification models. | oral | | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: Groups and Interactions | 2 |
7 | Hickox | Ryan | rhickox@cfa.harvard.edu | Harvard-Smithsonian Center for Astrophysics | A population of mid-infrared selected, obscured AGN in the Bootes field | We analyze an infrared-selected sample of $\sim$1500 active galactic nuclei (AGN) at redshifts $0.7oral | | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 | |
8 | Krumpe | Mirko | mkrumpe@aip.de | Astrophysical Institute of Potsdam, Germany | The XMM-Newton Survey in the Marano Field | We report on a medium deep XMM-Newton survey of the Marano field and optical follow-up observations. With a total of 110 identifications in our core sample we reach a completeness of $\sim$65\%. A fraction of 30\% of the XMM-Newton sources are identified as type II AGN with redshifts mostly below 1.0. We estimate absorbing column densities and show that the ratio of absorbed to unabsorbed objects is significantly higher for type II AGN than for type I AGN. However, we find a few unabsorbed type II AGN and significant number of heavily absorbed type I AGN, mostly at high redshifts. | oral | | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 |
9 | Lacy | Mark | mlacy@ipac.caltech.edu | Spitzer Science Center, Caltech | X-ray properties of Spitzer-selected type-2 quasars | Spitzer surveys are now finding many examples of obscured quasars. However, X-ray follow-up of these objects has been minimal, principally because a significant amount of exposure time (10-100ks) is needed to detect these objects, even those with relatively bright mid-infrared fluxes of several mJy at 24mu. Nevertheless, the presence of such a population has important implications for models of the hard X-ray background. I will present results for a subsample of 20 mid-infrared selected AGN in the SWIRE/XMM field, which demonstrate that a large fraction of obscured quasars have high X-ray absorption columns, and are likely to be Compton thick. | oral | I would be interested in seeing some discussion on the need (or otherwise) to follow-up obscured AGN detected in surveys other than X-ray (e.g. Spitzer, SDSS). Although this is expensive in X-ray time (either as a survey of e.g. a Spitzer field, or as a large number of pointed observations), these objects could be important for figuring out the nature of the hard X-ray background. | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 |
10 | Mainieri | Vincenzo | vmainieri@mpe.mpg.de | Max Planck Institute - European Southern Observatory | NH distribution from deep and large area X-ray surveys. | We present a detailed analysis of the X-ray spectra of point like sources in the XMM-COSMOS field. Our sample includes 134 X-ray sources with more than 100 net counts in the [0.3-10] keV energy band and that have been spectroscopically identified. The majority ($72\%$) of the sources are well described by a simple power-law model, $\sim 23\%$ of them show intrinsic absorption. The remaining $\sim 5\%$ of the sources require a more complex modeling with additional components to the simple power-law. The average photon spectral slope of our sources is $<\Gamma>=2.06\pm0.08$, with an intrinsic dispersion of $\sim 0.24$. The distribution of intrinsic absorbing column densities is different among broad line AGN and not broad line AGN. We will complement this sample with the results of our X-ray spectral analysis in the CDF-S area (~0.1 deg2). 99% of these sample has either a spectroscopic or a good photometric redshift. We demonstrated that at least part of a still mi! ssing population of Compton thick sources can be accounted for in deep X-ray surveys when all the X-ray sources are included (thanks to the use of accurate photometric redshifts for the still unidentified ones). In particular 14 sources have a pure reflection X-ray spectrum, typical of Compton-thick sources (N$_H > 1.5 \times 10^{24}$ cm$^{-2}$), which we can convert in a surface density as high as (200$\pm$50) deg$^{-2}$. We will finally present our current best estimate of the intrinsic N$_H$ distribution of AGN coming from these two surveys, discussing in details the corrections for incompleteness we had applied. | oral | -AGN-galaxy interaction -population of absorbed AGN still missed from the current X-ray surveys and how we can detect them in the mid-IR or sub-mm bands | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 |
11 | Treister | Ezequiel | etreiste@das.uchile.cl | ESO | The Evolution of Obscuration in AGN | One fundamental ingredient in our understanding of the AGN population is the ratio of obscured-to-unobscured AGN and whether it depends on parameters like luminosity or redshift. We have constructed the largest hard X-ray selected AGN sample, containing 2341 sources (1229 identified). We confirm that this fraction decreases with increasing luminosity and find that it increases with redshift. This is the first time that this is significantly detected using only optical spectroscopy. This may be interpreted as an evolution in the obscuration source. We calculate the integrated bolometric AGN emission finding it to be ~5% of the total extragalactic light. | oral | Do we still need more X-ray surveys? Deep? Wide? What do we still need to learn about the AGN population? | Monday: X-ray luminosity functions and evolution, Tuesday: AGN correlation functions, LSS, environments | 2 |
12 | Vignali | Cristian | cristian.vignali@bo.astro.it | Dipartimento di Astronomia, Universita` di Bologna | The obscured X-ray source population in the HELLAS2XMM survey: the Spitzer perspective | We present Spitzer IRAC and MIPS observations of a sample of eight high-luminosity, obscured AGN at z>1 selected in the 2-10 keV band from the 1.4 square degree HELLAS2XMM survey and characterized by extreme R-K colors (typically >5). The nuclear infrared spectral energy distributions of these AGN are computed using the K-band and Spitzer data, while the masses of the black holes are estimated using the local L(K)-M(BH) relation. By combining all the available information, the bolometric luminosity and Eddington ratio of these obscured AGN are derived and compared to literature results. | oral | | Monday: Type I and II AGN, Absorption, XBONGs, Tuesday: AGN correlation functions, LSS, environments | 2 |