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A survey of UV-excess AGNs in the South Galactic Pole - A sample for the analysis of the QSO clustering

Spectra, position, magnitudes and colors are presented for 485 faint () emission line objects selected with the ultraviolet-excess (UVX) criterion on a area of 24.6 deg2 in the South Galactic Pole. The objects were selected from the analysis of pixel-to-pixel stacking of COSMOS scans of UKST U J and R plates. The candidates were observed with the Meudon-ESO Fiber Optics System...

A long-term study of AGN X-ray variability - Structure function analysis on a ROSAT-XMM quasar sample

Context. Variability in the X-rays is a key ingredient in understanding and unveiling active galactic nuclei (AGN) properties. In this band, flux variations occur on short timescales (hours) as well as on larger timescales. While short timescale variability is often investigated in single source studies, only a few works are able to explore flux variation on very long timescales...

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

We present X-shooter at Very Large Telescope observations of a sample of 10 luminous, X-ray obscured quasi-stellar objects (QSOs) at z ∼ 1.5 from the XMM-COSMOS survey, expected to be caught in the transitioning phase from starburst to active galactic nucleus (AGN)-dominated systems. The main selection criterion is X-ray detection at bright fluxes (LX ≳ 1044 erg s−1) coupled to...

The redshift-space two-point correlation function of ELAIS-S1 galaxies

We investigate the clustering properties of galaxies in the recently completed ELAIS-S1 redshift survey through their spatial two-point autocorrelation function. We used a subsample of the ELAIS-S1 catalogue covering approximately 4 deg2 and consisting of 148 objects selected at 15 μm with a flux >0.5 mJy and a redshift z < 0.5. We detected a positive signal in the correlation...

The BeppoSAX High Energy Large Area Survey - IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources

, 674 Della Ceca , R. , Maccacaro , T. , Rosati , P. , & Braito , V. 2000 , A &A, 355 , 121 Dickey , J. M. , & Lockman , F. J. 1990 , ARA &A, 28 , 215 Fiore , F. , La Franca , F. , Giommi , P. , et al ... , & N. E. White [ astro-ph/0007118] Fiore , F. , La Franca , F. , Vignali , C. , et al. 2000b, New Astron., 5 , 143 Fiore , F. , Giommi , P. , Vignali , C. , et al. 2001 , MNRAS, submitted (Paper II

The HELLAS2XMM survey – XII. The infrared/submillimetre view of an X-ray selected type 2 quasar at z≈ 2

We present multiwavelength observations (from optical to submillimetre, including Spitzer and Submillimetre Common-User Bolometer Array) of H2XMMJ 003357.2−120038 (also GD 158_19), an X-ray selected, luminous narrow-line (type 2) quasar at z= 1.957 selected from the HELLAS2XMM survey. Its broad-band properties can be reasonably well modelled assuming three components: a stellar...

The BeppoSAX High Energy Large Area Survey (HELLAS) — VI. The radio properties

. , Gioia I. M. , Maccacaro T. , Schild R. E. , Wolter A. , Fleming T. A. , Henry J. P. , 1991 , ApJS, 76 , 813 Vignali C. , 2001 , PhD thesis , Bologna Univ. Vignali C. , Comastri A. , Fiore F. , La Franca F

The BeppoSAX High Energy Large Area Survey (HELLAS) — III. Testing synthesis models for the X-ray background

. , 2001 , MNRAS, 323 , 373 Fiore F. , Elvis M. , Giommi P. , Padovani P. , 1998 , ApJ, 492 , 79 Fiore F. , La Franca F., Giommi P. , Elvis M. , Matt G. , Comastri A. , Molendi S. , Gioia I. , 1999 , MNRAS ... . , Pompilio F. , La Franca F., 1999 , New Astron., 4 , 191 Miyaji T. , Hasinger G. , Schmidt M. , 2000 , A &A, 353 , 25 Mushotzky R. F. , Cowie L. L. , Barger A. J. , Arnaud K. A. , 2000 , Nat, 404 , 459 Perri

The radio-mid-infrared correlation and the contribution of 15-µm galaxies to the 1.4-GHz source counts

The radio counterparts to the 15-µm sources in the European Large Area ISO Survey southern fields are identified in 1.4-GHz maps down to ∼80 µJy. The radio-mid-infrared correlation is investigated and derived for the first time at these flux densities for a sample of this size. Our results show that radio and mid-infrared (MIR) luminosities correlate almost as well as radio and...

The HELLAS2XMM survey - VIII. Optical identifications of the extended sample

, 19 Fiore, F. 2004 , NuPhS, 132 , 69 Fiore , F. , La Franca , F. , Vignali , C. , et al. 2000 , NewA, 5 , 143 Fiore , F. , Brusa , M. , Cocchia , F. , et al. 2003 , A &A, 409 , 79 Georgakakis, A

Mid-infrared spectroscopy of infrared-luminous galaxies at z∼ 0.5–3

We present results on low-resolution mid-infrared (MIR) spectra of 70 IR-luminous galaxies obtained with the infrared spectrograph (IRS) onboard Spitzer. We selected sources from the European Large Area Infrared Survey with S15 > 0.8 mJy and photometric or spectroscopic z > 1. About half of the samples are quasi-stellar objects (QSOs) in the optical, while the remaining sources...

Large-scale structure in the ELAIS S1 Survey

We present an analysis of the two-point angular correlation function of The European Large-Area Infrared Space Observatory (ELAIS) S1 survey. The survey covers 4 deg2 and contains 462 sources detected at 15 μm to a 5σ flux limit of 0.45 mJy. Using the 329 extragalactic sources not repeated in different observations, we detect a significant clustering signal; the resulting angular...

The XMM-Newton survey of the ELAIS-S1 field - I. Number counts, angular correlation function and X-ray spectral properties

. La Franca 2 N. Sacchi 2 A. Franceschini 7 S. Berta 7 H. Buttery 6 J. E. Dias 6 INAF - Osservatorio Astronomico di Roma via Frascati Monteporzio-Catone Italy e-mail: 0 Dip. di Fisica, Universitá degli ... A&A Astronomy & Astrophysics S. Puccetti 1 F. Fiore V. D'Elia I. Pillitteri 0 C. Feruglio A. Grazian M. Brusa 5 P. Ciliegi 4 A. Comastri 4 C. Gruppioni 4 M. Mignoli 4 C. Vignali 3 G. Zamorani 4 F

Dust in active nuclei - I. Evidence for "anomalous"properties

, W. N. , Elvis , M. , Fabian , A. C. , Iwasawa , K. , & Mathur , S. 1999 , ApJ, 510 , 167 Filippenko , A. V. , & Sargent , W. L. W. 1988 , ApJ, 324 , 134 Fiore , F. , La Franca , F. , Giommi , P. , et ... al. 1999 , MNRAS, 306 , L55 Fiore , F. , La Franca , F. , Vignali , C. , et al. 2000 , New Astron., 5 , 143 Francis , P. J. , Hewett , P. C. , Foltz , C. B. , et al. 1991 , ApJ, 373 , 465 Gallagher , S

Final analysis of ELAIS 15-μm observations: method, reduction and catalogue

M. Vaccari 6 7 8 C. Lari 13 L. Angeretti 12 D. Fadda 11 C. Gruppioni 10 15 F. Pozzi 12 O. Prouton 7 H. Aussel 14 T. Babbedge 8 P. Ciliegi 15 A. Franceschini 7 E. Gonzalez-Solares 9 F. La Franca 4 S

The contribution of very massive high-redshift SWIRE galaxies to the stellar mass function

Context.In the last couple of years a population of very massive (>1011 ), high-redshift (z≥2) galaxies has been identified, but its role in galaxy evolution has not yet been fully understood.Aims.It is necessary to perform a systematic study of high-redshift massive galaxies, in order to determine the shape of the very massive tail of the stellar mass function and determine the...

The evolution of type 1 active galactic nuclei in the infrared (15 μm): the view from ELAIS-S1

We present the 15-μm luminosity function of type 1 active galactic nuclei (AGN1; quasi-stellar object+Seyfert 1). Our sample of 21 high-redshift sources is selected from the Preliminary Analysis catalogue in the S1 field of the European Large Area ISO Survey (ELAIS). To study the cosmological evolution of the AGN1 luminosity function, our sample has been combined with a local...

The contribution of faint active galactic nuclei to the hard X-ray background

Hard X-ray selection is the most efficient way to discriminate between accretion-powered sources, such as active galactic nuclei (AGN), and sources dominated by starlight. Hard X-rays are also less affected than other bands by obscuration. We have therefore carried out the BeppoSAX High Energy Large Area Survey (HELLAS) in the largely unexplored 5–10 keV band, finding 180 sources...

The BeppoSAX High Energy Large Area Survey (HELLAS) — II. Number counts and X-ray spectral properties

The BeppoSAX High Energy Large Area Survey (HELLAS) has surveyed about 85 deg2 of sky in the band down to a flux of . The source surface density of at the survey limit corresponds to a resolved fraction of the X-ray background (XRB) of the order of per cent. Hardness ratio analysis indicates that the spectra of a substantial fraction of the HELLAS sources (at least one-third) are...

The HELLAS2XMM survey - VI. X-ray absorption in the 1df AGN sample through a spectral analysis

The spectroscopic analysis of 117 serendipitous sources in the HELLAS2XMM 1df (1 degree field) survey is described. Of these, 106 sources, of which 86% have a spectroscopic redshift, are used to evaluate the fraction of X-ray absorbed (log ) Active Galactic Nuclei (AGN) in the 2-10 keV flux range  erg cm-2 s-1. This fraction turns out lower than what is predicted by two well...