The Chandra COSMOS Survey. I. Overview and Point Source Catalog (2009)
Elvis, Martin, Civano, Francesca, Vignali, Cristian, Puccetti, Simonetta, Fiore, Fabrizio, Cappelluti, Nico, ...
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.5 deg^2 of the COSMOS field (centered at 10 ^h , +02 ^o ) with an effective exposure of ~160 ks,...
The Chandra COSMOS Survey, I: Overview and Point Source Catalog (2009)
Elvis, Martin, Civano, Francesca, Vignali, Cristian, Puccetti, Simonetta, Fiore, Fabrizio, Cappelluti, Nico, ...
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra} program that has imaged the central 0.5 sq.deg of the COSMOS field (centered at 10h, +02deg) with an effective exposure of ~160ksec,...
Bianchi, Stefano, Piconcelli, Enrico, Chiaberge, Marco, Bailon, Elena Jimenez, Matt, Giorgio, Fiore, Fabrizio
We present the results of a Suzaku monitoring campaign of the Seyfert 2 galaxy, NGC7582. The source is characterized by very rapid (on timescales even lower than a day) changes of the column density...
The Chandra COSMOS survey - I. Overview and point source catalog (2009)
Elvis, Martin, Civano, Francesca, Vignali, Christian, Puccetti, Simonetta, Fiore, Fabrizio, Cappelluti, Nico, ...
Tagliaferri, Gianpiero, Ferrando, Philippe, Duigou, Jean-Michel Le, Pareschi, Giovanni, Laurent, Philippe, Malaguti, Giuseppe, ...
The discovery of X-ray emission from cosmic sources in the 1960s has opened a new powerful observing window on the Universe. In fact, the exploration of the X-ray sky during the 70s-90s has...
Mazzali, Paolo A., Valenti, Stefano, Della Valle, Massimo, Chincarini, Guido, Sauer, Daniel N., Benetti, Stefano, ...
The only supernovae (SNe) to have shown early gamma-ray or X-ray emission thus far are overenergetic, broad-lined Type Ic SNe (Hypernovae - HNe). Recently, SN 2008D shows several novel features: (i)...
Finding Local Low-mass Supermassive Black Holes (2008)
Mathur, Smita, Ghosh, Himel, Ferrarese, Laura, Fiore, Fabrizio
The low-mass end of the supermassive black hole mass function is unknown and difficult to determine. Here we discuss our successful program to find active nuclei of late type "normal" galaxies using...
Detecting Low-Mass Supermassive Black Holes (2008)
Ghosh, Himel, Mathur, Smita, Fiore, Fabrizio, Ferrarese, Laura
We demonstrate the feasibility of uncovering supermassive black holes in late-type, quiescent spiral galaxies by detecting signs of very low-level nuclear activity. We use a combination of x-ray...
The candidate filament close to the 3C295 galaxy cluster: optical and X-ray spectroscopy (2008)
D'Elia, Valerio, Fiore, Fabrizio, Mathur, Smita, Cocchia, Filomena
We present a detailed analysis of the overdensity of X-ray sources colse to the 3C 295 galaxy cluster (z=0.46) to assess whether it is associated with a filament of the large-scale structure of the...
Low-Level Nuclear Activity in Nearby Spiral Galaxies (2008)
Ghosh, Himel, Mathur, Smita, Fiore, Fabrizio, Ferrarese, Laura
We are conducting a search for supermassive black holes (SMBHs) with masses below 10^7 M_sun by looking for signs of extremely low-level nuclear activity in nearby galaxies that are not known to be...
Mazzali, Paolo A., Valenti, Stefano, Della Valle, Massimo, Chincarini, Guido, Sauer, Daniel N., Benetti, Stefano, ...
The variable X-ray light curve of GRB 050713A: the case of refreshed shocks (2007)
Guetta, Dafne, Fiore, Fabrizio, D'Elia, Valerio, Perna, R., Antonelli, L. Angelo, Piranomonte, Silvia, ...
We present a detailed study of the spectral and temporal properties of the X-ray and optical emission of GRB050713a up to 0.5 day after the main GRB event. The X-ray light curve exhibits large...
Miyaji, Takamitsu, Zamorani, Giovanni, Cappelluti, Nico, Gilli, Roberto, Griffiths, Richard E., Comastri, Andrea, ...
Compton thick AGN in the Suzaku era (2007)
Comastri, Andrea, Gilli, Roberto, Vignali, Cristian, Matt, Giorgio, Fiore, Fabrizio, Iwasawa, Kazushi
The obscured X-ray source population in the HELLAS2XMM survey: the Spitzer view (2007)
Vignali, Cristian, Pozzi, Francesca, Comastri, Andrea, Pozzetti, Lucia, Mignoli, Marco, Gruppioni, Carlotta, ...
Miyaji, Takamitsu, Zamorani, Giovanni, Cappelluti, Nico, Gilli, Roberto, Griffiths, Richard E., Comastri, Andrea, ...
We present the first results of the measurements of angular auto-correlation functions (ACFs) of X-ray point sources detected in the XMM-Newton observations of the 2 deg2 COSMOS field (XMM-COSMOS). A...
The cosmic X-ray background and the population of the most heavily obscured AGNs (2006)
Frontera, Filippo, Orlandini, Mauro, Landi, Raffaella, Comastri, Andrea, Fiore, Fabrizio, Setti, Giancarlo, ...
We report on an accurate measurement of the CXB in the 15-50 keV range performed with the Phoswich Detection System (PDS) instrument aboard the BeppoSAX satellite. We establish that the most likely...
Probing the Local Group Medium Toward Mkn 421 with Chandra and FUSE (2005)
Williams, Rik J., Mathur, Smita, Nicastro, Fabrizio, Elvis, Martin, Drake, Jeremy J., Fang, Taotao, ...
We report the detection of highly-ionized gas at z~0 seen in resonant UV and X-ray absorption lines toward the z=0.03 blazar Mkn 421. A total of 13 X-ray and 3 UV lines were measured (or upper limits...
Chandra Detection of the First X-ray Forest along the Line of Sight To Mkn 421 (2005)
Nicastro, Fabrizio, Mathur, Smita, Elvis, Martin, Drake, Jeremy, Fiore, Fabrizio, Fang, Taotao, ...
We present the first >=3.5 sigma (conservative) or >=5.8 sigma (sum of lines significance) detection of two Warm-Hot Intergalactic Medium (WHIM) filaments at z>0, which we find along the line of...
Spectral changes during six years of Scorpius X-1 monitoring with BeppoSAX Wide Field Cameras (2005)
Santolamazza, Patrizia, Fiore, Fabrizio, Burderi, Luciano, Di Salvo, Tiziana
We analyse a sample of fifty-five observations of Scorpius X-1 available in the BeppoSAX Wide Field Camera public archive and spanning over the six years of BeppoSAX mission life. Spectral changes...
Measured Cosmological Mass Density in the WHIM: the Solution to the 'Missing Baryons' Problem (2005)
Nicastro, Fabrizio, Elvis, Martin, Fiore, Fabrizio, Mathur, Smita
We review the current high-significance X-ray detections of Warm-Hot Intergalactic Medium (WHIM) filaments at z>0 along the lines of sight to the two blazars Mrk 421 (z=0.03) and 1ES 1028+511...
The density and masses of obscured Black Holes (2004)
Comastri, Andrea, Fiore, Fabrizio
Recent Chandra and XMM-Newton surveys have uncovered a large fraction of the obscured AGN responsible of the hard X-ray background. One of the most intriguing results of extensive programs of...
The faint X-ray Source Population near 3C 295 (2004)
D'Elia, Valerio, Fiore, Fabrizio, Elvis, Martin, Cappi, Massimo, Mathur, Smita, Mazzotta, Pasquale, ...
We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster (z=0.46) aimed at the search for clustering of X-ray sources. We applied three...
High Energy Large Area Surveys: from BeppoSAX to Chandra and XMM-Newton (2003)
Hard X-ray observations are the most efficient way to discriminate accretion-powered sources from star-light. Furthermore, hard X-rays are less affected than other bands by obscuration. For these...
The X-ray absorber of PKS2126-158 (2003)
Fiore, Fabrizio, Elvis, Martin, Maiolino, Roberto, Nicastro, Fabrizio, Siemiginowska, Aneta, Stratta, Giulia, ...
BeppoSAX observed the z=3.27 quasar PKS2126-158 on 1999 May 24-28 when its 2-10keV and 0.1-2.5keV fluxes were 1.1E-11 and 4.4E-12 cgs respectively, a factor of 2 higher than in all previous ROSAT and...
Chandra Discovery of an X-ray jet and Extended X-ray Structure in z=0.63 quasar, B2 0738+313 (2003)
Siemiginowska, Aneta, Stanghellini, Carlo, Brunetti, Gianfranco, Fiore, Fabrizio, Aldcroft, Thomas L., Bechtold, Jill, ...
We have made a 30 ksec Chandra observation of the redshift z=0.63 GPS quasar B2 0738+313. We detected X-ray emission from the core and have discovered a 200 kpc (projected on the sky) X-ray jet. The...
A High Resolution Intergalactic Explorer for the Soft X-ray/FUV (2003)
Elvis, Martin, Fiore, Fabrizio, Team, The CWE
We present a mission concept for high resolution X-ray spectroscopy with a resolving power, R~6000, (c.f. R=
Perna, Rosalba, Lazzati, Davide, Fiore, Fabrizio
The interaction of a radiation field with a dusty medium is a relevant issue in several astrophysical contexts. We use the time-dependent photoionization code in a dusty medium developed by Perna &...
Illuminated, and enlightened, by GRB 991216 (2000)
Vietri, Mario, Ghisellini, Gabriele, Lazzati, Davide, Fiore, Fabrizio, Stella, Luigi
We consider models for the generation of the emission line recently discovered in the X-ray afterglow spectrum of several bursts, and especially of GRB 991216 observed by Chandra. These observations...
BeppoSAX Observations of the Maser Sy2 Galaxy: ESO103-G35 (2000)
Wilkes, Belinda J., Mathur, Smita, Fiore, Fabrizio, Antonelli, Angelo, Nicastro, Fabrizio
We have made BeppoSAX observations of the Seyfert 2/1.9 galaxy ESO103-G35, which contains a nuclear maser source and is known to be heavily absorbed in the X-rays. Analysis of the X-ray spectra...
Sub-mm and X-ray background: Two unrelated phenomena? (2000)
Severgnini, Paola, Maiolino, Roberto, Salvati, Marco, Axon, David, Cimatti, Andrea, Fiore, Fabrizio, ...
Also archived in: arXiv:astro-ph/0006233 v1 16 Jun 2000
Sub-mm and X-ray background: Two unrelated phenomena? (2000)
Severgnini, Paola, Maiolino, Roberto, Salvati, Marco, Axon, David, Cimatti, Andrea, Fiore, Fabrizio, ...
Also archived in: arXiv:astro-ph/0006233 v1 16 Jun 2000
150 keV Emission from PKS2149-306 with BeppoSAX (2000)
Elvis, Martin, Fiore, Fabrizio, Siemiginowska, Aneta, Bechtold, Jill, Mathur, Smita, McDowell, Jonathan
A BeppoSAX observation of the z=2.34 quasar PKS2149-306 produced a strong signal in the high energy PDS instrument up to a maximum observed energy of nearly 50 keV, 150 keV in the quasar frame. The...
Nicastro, Fabrizio, Fiore, Fabrizio, Matt, Giorgio
We present photoionization models accounting for both photoelectric and resonant absorption. Resonance absorption lines from C, O, Ne, Mg, Si S and Fe between 0.1 and 10 keV are treated. In...
NGC 7582: The Prototype Narrow-Line X-ray Galaxy (1998)
Schachter, Jonathan F., Fiore, Fabrizio, Elvis, Martin, Mathur, Smita, Wilson, Andrew S., Morse, Jon A., ...
NGC 7582 is a candidate prototype of the Narrow Line X-ray Galaxies (NLXGs) found in deep X-ray surveys. An ASCA observation shows the hard (> 3 keV) X-ray continuum of NGC 7582 drops 40% in ~6 ks,...
The variability properties of X-ray steep and X-ray flat quasars (1998)
Fiore, Fabrizio, Laor, Ari, Elvis, Martin, Nicastro, Fabrizio, Giallongo, Emanuele
We have studied the variability of 6 low redshift, radio quiet `PG' quasars on three timescales (days, weeks, and months) using the ROSAT HRI. The quasars were chosen to lie at the two extreme ends...
BeppoSAX Observations of Unprecedented Synchrotron Activity in the BL Lac Object Mkn 501 (1997)
Pian, Elena, Vacanti, Giuseppe, Tagliaferri, Gianpiero, Ghisellini, Gabriele, Maraschi, Laura, Treves, Aldo, ...
The BL Lac object Mkn 501, one of the only three extragalactic sources (with Mkn 421 and 1ES 2344+514) so far detected at TeV energies, was observed with the BeppoSAX satellite on 7, 11, and 16 April...
X-ray Spectral Survey of WGACAT Quasars, I: Spectral Evolution & Low Energy Cut-offs (1997)
Fiore, Fabrizio, Elvis, Martin, Giommi, Paolo, Padovani, Paolo
We have used the WGA catalog of ROSAT PSPC X-ray sources to study the X-ray spectrum of about 500 quasars in the redshift interval 0.1--4.1, detected with a signal to noise better than 7. We have...
Elvis, Martin, Fiore, Fabrizio, Giommi, Paolo, Padovani, Paolo
We have selected quasars with X-ray colors suggestive of a low energy cut-off, from the ROSAT PSPC pointed archive. We examine the radio and optical properties of these 13 quasars. Five out of the...
Associated Absorption at Low and High Redshift (1996)
Elvis, Martin, Mathur, Smita, Wilkes, Belinda J., Fiore, Fabrizio, Giommi, Paolo, Padovani, Paolo, ...
Combining information on absorbing material in AGN from X-ray and the UV creates a powerful investigative tool. Here we give examples from both low and high redshift.
Are the X-ray Spectra of Flat-spectrum Radio Quasars and BL Lacertae Objects Different? (1996)
Padovani, Paolo, Giommi, Paolo, Fiore, Fabrizio
We study the X-ray spectra of 114 flat-spectrum radio quasars (FSRQ) using the hardness ratios as given in the WGA catalogue of ROSAT sources. This sample includes all WGA FSRQ with high-quality data...
Laor, Ari, Fiore, Fabrizio, Elvis, Martin, Wilkes, Belinda J., McDowell, Jonathan C.
We present the final results of a ROSAT PSPC program to study the soft X-ray emission properties of a complete sample of low $z$ quasars. The main results are: 1. There is no evidence for significant...