Results for "A. Cappi"

total 225673took 0.14s
The Spatial Distribution of Nearby Galaxy Clusters in the Northern and Southern Galactic HemispheresMay 08 1992We compare the spatial distributions of galaxy clusters in the northern and southern galactic hemispheres, and the Abell and ACO clusters distributions. We perform a statistical (correlation and cluster) analysis of a sample of Abell and ACO galaxy clusters ... More
High-Order Correlations of Rich Galaxy ClustersJul 26 1994Jul 28 1994We analyse the two--dimensional all--sky distribution of rich Abell and ACO galaxy clusters by using counts in cells and measuring the high--order area--averaged angular correlation functions. Confirming previous results, we find a well defined hierarchical ... More
The X-ray spectrum of the Gamma Bright Quasar S5 0836+710Dec 11 1995We present the results of an ASCA observation of the high redshift flat spectrum radio quasar S5 0836+710. The $\sim 0.4-10$ keV X-ray spectrum is remarkably flat with $\Gamma \sim 1.4$ and substantial intrinsic absorption at low energy. The spectral ... More
High-resolution re-simulations of massive DM halos and the Fundamental Plane of galaxy clustersDec 05 2002Pure N-body high-resolution re-simulations of 13 massive dark matter halos in a Lambda-CDM cosmology are presented. The resulting sample is used to investigate the physical origin of the Fundamental Plane, ``Faber-Jackson'', and ``Kormendy'' relations ... More
Real and Redshift-Space Clustering in the ESP Galaxy Redshift SurveyOct 12 1998We discuss the two-point correlation properties of galaxies in the ESO Slice Project (ESP) redshift survey, both in redshift and real space. The redshift-space correlation function xi(s) for the whole magnitude-limited survey is well described by a power ... More
The Redshift and Real-Space Correlation Functions from the ESP Galaxy Redshift SurveyOct 06 1998We discuss the behaviour of the redshift- and real-space correlation functions from the ESO Slice Project (ESP) galaxy redshift survey. xi(s) for the whole survey is positive out to ~80/h Mpc, with a smooth break from a shallow power law. Comparison to ... More
Nustar Measurement Of Coronal Temperature In Two Luminous, High Redshift QsosApr 09 2019X-ray emission from AGN is believed to be produced via Comptonization of optical/UV seed photons emitted by the accretion disk, up-scattered by hot electrons in a corona surrounding the black hole. A critical compactness vs. temperature threshold is predicted ... More
Clues on galaxy and cluster formation from their scaling relationsNov 18 2003By means of high-resolution N-body simulations in a LambdaCDM cosmology, we verify that scaling relations similar to those observed for nearby galaxy clusters are also defined by their dark matter hosts; the slopes, however, are not the same. We then ... More
The First High-Energy X-Ray Spectrum of a Z$>2$ Radio-Quiet Quasar: Q1101-264Jan 17 1997Results of the X-ray spectral analysis of the high-redshift radio-quiet quasar Q1101-264 are presented. The ASCA spectrum suggests a marginal evidence of a FeK$\alpha$ emission line at about 2 keV (observer's frame). Both the ASCA and ROSAT spectra are ... More
The Fundamental Plane of Galaxy ClustersApr 20 1993Velocity dispersion $\sigma$, radius $R$ and luminosity $L$ of elliptical galaxies are known to be related, leaving only two degrees of freedom and defining the so-called ``fundamental plane". In this {\em Letter} we present observational evidence that ... More
The scaling relations of galaxy clusters and their dark matter halosJul 08 2003Sep 22 2003Like early-type galaxies, also nearby galaxy clusters define a Fundamental Plane, a luminosity-radius, and a luminosity-velocity dispersion relations, whose physical origin is still unclear. By means of high resolution N--body simulations of massive dark ... More
Multiple merging events in Abell 521Nov 27 2002We present a detailed spatial and dynamical analysis of the central $\sim$~2.2~\h~Mpc region of the galaxy cluster Abell~521 (z=0.247), based on 238 spectra obtained at the 3.6~m Telescope of ESO and at the CFHT. From the analysis of the 125 galaxies ... More
Is the Universe a fractal? Results from the SSRS2Apr 08 1998We perform a fractal analysis of the Southern Sky Redshift Survey 2, following the methods prescribed by Pietronero and collaborators, to check their claim that the galaxy distribution is fractal at all scales, and we discuss and explain the reasons of ... More
ASCA and ROSAT X-ray Spectra of IC 5063 and NGC 3998Jan 17 1997The results of the 0.1-10 keV spectral analysis of IC 5063 (Narrow Line Radio Galaxy) and NGC 3998 (LINER) are presented. In both cases there is evidence of a FeK$\alpha$ emission line, but its width is poorly constrained. The highly absorbed spectrum ... More
Highly Ionized Neon in the Spectrum of the Sey 2 Galaxy NGC 4507 ?Jan 17 1997Results of an ASCA X-ray observation of NGC 4507 are presented. The spectrum is best parameterized by a double power law (or a partial covering) model plus a narrow FeK$\alpha$ emission line likely due to the line-of-sight absorption matter. The data ... More
Dynamical state and star formation properties of the merging galaxy cluster Abell 3921Sep 03 2004We present the results of a new spectroscopic and photometric survey of the central region of the galaxy cluster A3921 (z=0.094). We detect the presence of two dominant clumps of galaxies: a main cluster centred on the BCG (A3921-A), and a NW sub-cluster ... More
Testing Cosmological Models with Negative PressureMay 22 2001There is now strong evidence that the main contribution to the cosmic energy density is not due to matter, but to another component with negative pressure. Its nature is still unknown: it could be the vacuum energy, manifesting itself as a positive cosmological ... More
Relativistic blue- and red-shifted absorption lines in AGNsOct 04 2006Current, accumulating evidence for (mildly) relativistic blue- and red-shifted absorption lines in AGNs is reviewed. XMM-Newton and Chandra sensitive X-ray observations are starting to probe not only the kinematics (velocity) but also the dynamics (accelerations) ... More
BeppoSAX observations of LINER-2 galaxiesFeb 08 2002We present BeppoSAX observations of 6 ``type-2'' LINER and ``transition'' galaxies (NGC3379, NGC3627, NGC4125, NGC4374, NGC5195 and NGC5879)from the Ho et al. (1997) spectroscopic sample of nearby galaxies. All objects are detected in the 2-10 keV band, ... More
The Vimos VLT Deep Survey: Compact structures in the CDFSJul 29 2005We have used the Vimos VLT Deep Survey in combination with other spectroscopic, photometric and X-ray surveys from literature to detect several galaxy structures in the Chandra Deep Field South (CDFS). Both a friend-of-friend based algorithm applied to ... More
Comparison of two optical cluster finding algorithms for the new generation of deep galaxy surveysOct 03 2003We present a comparison between two optical cluster finding methods: a matched filter algorithm using galaxy angular coordinates and magnitudes, and a percolation algorithm using also redshift information. We test the algorithms on two mock catalogues. ... More
2-10 keV luminosity of high-mass binaries as a gauge of ongoing star-formation rateFeb 24 2004Based on recent work on spectral decomposition of the emission of star-forming galaxies, we assess whether the integrated 2-10 keV emission from high-mass X-ray binaries (HMXBs), L_{2-10}^{HMXB}, can be used as a reliable estimator of ongoing star formation ... More
NGC 4151: an intrinsically average Seyfert 1Aug 02 2001Mar 18 2002We present a detailed analysis of a long, 100 ksec, observation of NGC 4151 by ASCA, contemporaneous with an observation by the CGRO/OSSE. We fit the data with physical models including an Fe K line and Compton reflection both relativistically broadened ... More
Have we detected the most luminous ULX so far?Jul 21 2006Jul 24 2006We report the XMM-Newton detection of a moderately bright X-ray source superimposed on the outer arms of the inactive spiral galaxy MCG-03-34-63 (z=0.0213). It is clearly offset from the nucleus (by about 19'') but well within the D25 ellipse of the galaxy, ... More
On the nature of the X-ray absorption in the Seyfert 2 galaxy NGC 4507Oct 28 1997We present results of the ASCA observation of the Seyfert 2 galaxy NGC 4507. The 0.5-10 keV spectrum is rather complex and consists of several components: (1) a hard X-ray power law heavily absorbed by a column density of about 3 10^23 cm^-2, (2) a narrow ... More
The variable ROSAT X-ray spectrum of the BL Lac 0716+714Sep 27 1994The BL Lac object 0716+714 is a powerful flat spectrum radio source detected by CGRO-EGRET at $\gamma$-ray energies. It has been observed for about 21000 s over two days by the X-ray telescope onboard the ROSAT satellite and strong flux and spectral variations ... More
Probing the hard X-ray properties of high-redshift Radio-Quiet Quasars with ASCADec 09 1998This paper reports the X-ray spectral analysis of 5 high-redshift (z \ge 2) radio-quiet quasars observed by ASCA. A simple power law continuum plus cold Galactic absorption model well fits all the spectra (tipically between $\sim$ 2-30 keV in the sources ... More
Is the X-ray spectrum of the Seyfert 2 galaxy NGC5252 intrinsically flat?Oct 11 1995The first X-ray observation of the Seyfert 2 galaxy NGC5252 is reported. ASCA collected $\sim 4000$ photons/detector enough to perform an accurate spectral analysis of this source. The luminosity of NGC5252 is L$_{\rm X}$(0.7-10 keV) $\simeq 2.6 \times ... More
X-ray imaging of the ionisation cones in NGC 5252Mar 08 2010The physical conditions of the gas forming the narrow line regions (NLR) in active galactic nuclei (AGN) have been extensively studied in the optical band. We take advantage of the spectacular extension ($\sim$15") of the NLR in the type II Seyfert galaxy ... More
Relativistic inflow in the Seyfert 1 Mrk 335 revealed through X-ray absorptionDec 12 2006The analysis of hard X-ray features in XMM-Newton data of the bright Sy 1 galaxy Mrk 335 is reported here. The presence of a broad, ionised iron K alpha emission line in the spectrum, first found by Gondoin et al.(2002), is confirmed. The broad line can ... More
PG 1211+143: probing high frequency lags in a high mass AGNAug 17 2011We present the timing analysis of the four archived XMM-Newton observations of PG 1211+143. The source is well-known for its spectral complexity, comprising a strong soft-excess and different absorption systems. Soft energy band (0.3-0.7 keV) lags are ... More
Properties of Very Luminous GalaxiesMar 04 1998Recent analysis of the SSRS2 data based on cell-counts and two-point correlation function has shown that very luminous galaxies are much more strongly clustered than fainter galaxies. In fact, the amplitude of the correlation function of very luminous ... More
The complex FeK line of the Narrow-Line Seyfert 1 galaxy IRAS13349+2438Jul 28 2003The observation of the Narrow-Line Seyfert 1 galaxy IRAS13349+2438 performed by XMM-Newton European Photon Imaging Camera between 0.3-10 keV, is presented here. The broadband spectrum of the source is dominated at low energies (E < 2 keV) by a strong ... More
ASCA view on High-Redshift Radio-Quiet QuasarsJul 12 2000We briefly discuss the latest ASCA results on the X-ray spectral properties of high-redshift radio-quiet quasars.
ASCA and ROSAT X-ray Spectra of High-Redshift Radio-Loud QuasarsOct 25 1996Results are presented on the X-ray properties of 9 high-redshift (1.2 < z < 3.4) radio-loud quasars (RLQs) observed by ASCA (10 observations) and ROSAT (11 observations, for a subset of 6 quasars). New ASCA observations of S5 0014+81 (z = 3.38) and S5 ... More
Five contributions to the 3rd ESO-VLT Workshop ``Galaxy Scaling Relations''Dec 13 1996In the first contribution the basic problems posed by the existence of the Fundamental Plane (FP), and its relations with the Virial Theorem are discussed. Various possibilities are presented that can produce the observed uniform departure from homology ... More
Biasing and high-order statistics from the SSRS2Sep 07 1998We analyze different volume-limited samples extracted from the Southern Sky Redshift Survey (SSRS2), using counts-in-cells to compute the Count Probability Distribution Function (CPDF).From the CPDF we derive volume-averaged correlation functions to fourth ... More
On the relativistic iron line and soft excess in the Seyfert 1 galaxy Markarian 335Aug 06 2007We report on a 133 ks XMM-Newton observation of the Seyfert 1 galaxy Markarian 335. The 0.4-12 keV spectrum contains an underlying power law continuum, a soft excess below 2 keV, and a double-peaked iron emission feature in the 6-7 keV range. We investigate ... More
XMM-Newton study of the complex and variable spectrum of NGC 4051Feb 08 2006Feb 11 2006We study the X-ray spectral variability of the Narrow Line Seyfert 1 galaxy NGC 4051 as observed during two XMM-Newton observations. The data show evidence for a neutral and constant reflection component and for constant emission from photoionized gas, ... More
Warm absorber, reflection and Fe K line in the X-ray spectrum of IC 4329AOct 12 1995Results from the X-ray spectral analysis of the ASCA PV phase observation of the Seyfert 1 galaxy IC 4329A are presented. We find that the 0.4 - 10 keV spectrum of IC 4329A is best described by the sum of a steep ($\Gamma \sim 1.98$) power-law spectrum ... More
BeppoSAX uncovers a type-2 QSO in the hyperluminous infrared galaxy IRAS 09104+4109Dec 07 1999We studied with BeppoSAX the infrared luminous galaxy IRAS 09104+4109 over a very wide X-ray band from 0.1 to 80 keV. Our observations indicate the dominance of a thermal component at energies below 8 keV, which we attribute to the free-free emission ... More
Energy-shifted lines in XMM-Newton spectra of Seyfert GalaxiesNov 15 2005In the recent literature on AGNs it has been often reported that spectra of Seyfert 1 Galaxies show resonant absorption lines of Fe K which are redshifted from the rest frame position. Such lines are often found with marginal significance but, if real, ... More
Biasing in the Galaxy DistributionMay 20 1996We investigate the variation of galaxy clustering with luminosity using the recently completed SSRS2 sample. Clustering measurements based on the two-point correlation function and the variance of counts in cells reveal the existence of a strong dependence ... More
First ASCA results for high-redshift Radio-Quiet QuasarsSep 07 1998Here we report the X-ray spectral analysis of 5 high-redshift ($z \geq 2$) radio-quiet quasars (RQQs) observed with the ASCA satellite. A simple power law with Galactic absorption model well fits the data. There is no evidence of a reflection component. ... More
X-ray absorption lines suggest matter infalling onto the central black-hole of Mrk 509Jun 28 2005Evidence for both red- and blue-shifted absorption lines due to ionized Fe in the X-ray spectrum of the Seyfert 1 galaxy Mrk 509 are reported. These features appear to be transient on time-scales as short as ~20 ks, and have been observed with two different ... More
The VIMOS VLT Deep Survey: Testing the gravitational instability paradigm at z ~ 1Feb 13 2008We have reconstructed the three-dimensional density fluctuation maps to z ~ 1.5 using the distribution of galaxies observed in the VVDS-Deep survey. We use this overdensity field to measure the evolution of the probability distribution function and its ... More
Edgar Allan Poe: the first man to conceive a Newtonian evolving UniverseJun 17 2015The notion that we live in an evolving universe was established only in the twentieth century with the discovery of the recession of galaxies by Hubble and with the Lemaitre and Friedmann's interpretation in the 1920s. However, the concept of an evolving ... More
Beppo-SAX temperature maps of galaxy clusters in the Corona Borealis supercluster: A2061, A2067 and A2124Jun 24 2004In this paper we present the analysis of Beppo-SAX observations of the cluster pairs A2061-A2067 and A2122-A2124, located in the Corona Borealis supercluster, which have been selected as candidate merging clusters. The aim of this work is to study the ... More
On the presence of ultra-fast outflows in the WAX sample of Seyfert galaxiesJun 10 2014The study of winds in active galactic nuclei (AGN) is of utmost importance as they may provide the long sought-after link between the central black hole and the host galaxy, establishing the AGN feedback. Recently, Laha et al. (2014) reported the X-ray ... More
Inferring black hole spins and probing accretion/ejection flows in AGNs with the Athena X-ray Integral Field UnitJun 06 2019Active Galactic Nuclei (AGN) display complex X-ray spectra which exhibit a variety of emission and absorption features, that are commonly interpreted as a combination of i) a relativistically smeared reflection component, resulting from the irradiation ... More
Complex Absorption Hides a Type II QSO in IRAS 13197-1627Oct 09 2003We report on the analysis of a BeppoSAX observation of IRAS 13197-1627. The complexity of the broad band (0.3-100 keV) spectrum of the source prevents us from selecting from two possible best-fit models, i.e. one based on a partial covering and the other ... More
BeppoSAX/PDS identification of the true counterpart of the Piccinotti source H0917-074Aug 21 2002High energy emission has been discovered serendipitously by the BeppoSAX/PDS telescope in the ~1.3 degree field of view around the Piccinotti source H0917-074. A re-pointing of BeppoSAX/NFI has allowed the association of this emission with the Seyfert ... More
Galaxy clusters in the CFHTLS. First matched filter candidate catalogue of the Deep fieldsSep 29 2006We apply a matched-filter cluster detection algorithm to the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) i-band data for the Deep-1, Deep-2, Deep-3 and Deep-4 fields covering a total of 4square degrees. To test the implemented procedure we carry ... More
Spectroscopic identification of ten faint hard X-ray sources discovered by ChandraMar 18 2000We report optical spectroscopic identifications of 10 hard (2-10 keV) X-ray selected sources discovered by Chandra. The X-ray flux of the sources ranges between 1.5 and 25 x 10-14 cgs, the lower value being 3 times fainter than in previous BeppoSAX and ... More
ASCA observations of two steep soft X-ray quasarsApr 24 1998Steep soft X-ray (0.1-2 keV) quasars share several unusual properties: narrow Balmer lines, strong FeII emission, large and fast X-ray variability, rather steep 2-10 keV spectrum. These intriguing objects have been suggested to be the analogs of Galactic ... More
Discovery of a relation between black hole mass and soft X-ray time lags in active galactic nucleiDec 30 2011Feb 24 2013We carried out a systematic analysis of time lags between X-ray energy bands in a large sample (32 sources) of unabsorbed, radio quiet active galactic nuclei (AGN), observed by XMM-Newton. The analysis of X-ray lags (up to the highest/shortest frequencies/time-scales), ... More
Testing warm Comptonization models for the origin of the soft X-ray excess in AGNOct 13 2017The X-ray spectra of many active galactic nuclei (AGN) show a soft X-ray excess below 1-2 keV on top of the extrapolated high- energy power law. The origin of this component is uncertain. It could be a signature of relativistically blurred, ionized reflection, ... More
The broad band spectrum and variability of NGC 4151 observed by BeppoSAXNov 15 2006We present an analysis of all SAX observations of NGC 4151. This source was observed 5 times from 1996 to 2001 with durations ranging from a day to four days. The intrinsic continuum, is absorbed at low energies by a complex system: a cold patchy absorber ... More
The composite starburst/AGN nature of the superwind galaxy NGC 4666Jun 16 2004Jun 22 2004We report the discovery of a Compton-thick AGN and of intense star-formation activity in the nucleus and disk, respectively, of the nearly edge-on superwind galaxy NGC 4666. Spatially unresolved emission is detected by BeppoSAX only at energies <10 keV, ... More
ASCA detection of the FeK edge in the spectrum of the Seyfert 2 galaxy IRAS 04575-7537: a sign of a complex absorberDec 18 1997ASCA X-ray spectral analysis of the Seyfert 2 galaxy IRAS 04575-7537 is presented. The main result is the presence of a significant iron edge at a rest energy of 7.13^+0.21_-0.16 keV. The spectrum is flat (Gamma = 1.5) with a substantial absorption Nh ... More
Merging history of three bimodal clustersSep 10 2010We present a combined X-ray and optical analysis of three bimodal galaxy clusters selected as merging candidates at z ~ 0.1. These targets are part of MUSIC (MUlti--Wavelength Sample of Interacting Clusters), which is a general project designed to study ... More
BeppoSAX observation of NGC 7674: a new reflection-dominated Seyfert 2 galaxyNov 13 1997The Seyfert 2 galaxy NGC 7674 has been observed within the BeppoSAX Core Programme with the onboard narrow field instruments between 0.1 and 100 keV. The broad-band spectrum shows four most relevant spectral components: a) a soft excess below ~2 keV; ... More
Unveiling the AGN powering the "Composite" Seyfert/Star-forming galaxy NGC 7679: BeppoSAX and ASCA resultsJun 25 2001We discuss BeppoSAX observations and archive ASCA data of NGC 7679, a nearby, nearly face-on SB0 galaxy in which starburst and AGN activities coexist. The X-ray observations reveal a bright (L_{0.1-50 keV} \sim 2.9 \times 10^{43} erg s^{-1}) and variable ... More
Probing variability patterns of the Fe K line complex in bright nearby AGNsJul 09 2009The unprecedented sensitivity of current X-ray telescopes allows for the first time to address the issue of the Fe K line complex variability patterns in bright, nearby AGNs. We examine XMM-Newton observations of the brightest sources of the FERO sample ... More
Abell 521: Dynamical analysis of a young clusterMar 31 1999We present the results of a dynamical analysis of the rich X-Ray luminous galaxy cluster Abell 521, and discuss the nature of the arc-like structure first noted by Maurogordato et al. (1996). Our study is based on radial velocities for 41 cluster members, ... More
Star formation in the merging galaxy cluster Abell 3921Oct 04 2005Through a combined optical and radio analysis, we have investigated the possible connection between the dynamical state of the merging cluster A3921 and its star formation properties, reaching the conclusion that the on-going merger is triggering a SF ... More
High-energy monitoring of NGC 4593 with XMM-Newton and NuSTAR. X-ray spectral analysisAug 09 2016We present results from a joint Xmm-Newton/NuSTAR monitoring of the Seyfert 1 NGC 4593, consisting of 5x20 ks simultaneous observations spaced by two days, performed in January 2015. The source is variable, both in flux and spectral shape, on time-scales ... More
High-energy monitoring of NGC 4593 II. Broadband spectral analysis: testing the two-corona modelDec 07 2018It is widely believed that the primary X-ray emission of AGN is due to the Comptonisation of optical-UV photons from a hot electron corona, while the origin of the 'soft-excess' is still uncertain and matter of debate. A second Comptonisation component, ... More
BeppoSAX view of NGC 526A: a Seyfert 1.9 galaxy with a flat spectrumOct 05 2001In the present work we report the BeppoSAX observation of the Seyfert 1.9 galaxy NGC 526A in the band 0.1-150 keV. The high energy instrument onboard, PDS, has succeeded in measuring for the first time the spectrum of this source in the 13-150 keV range. ... More
X-ray properties of the "Composite" Seyfert/Star-forming galaxiesJul 28 2004An enigmatic, small class of IR and X-ray luminous sources, named ``Composite'' starburst/Seyfert galaxies, has been defined from IRAS and RASS data. The objects have optical spectra dominated by the features of HII galaxies (plus, in some cases, weak ... More
An XMM-Newton hard X-ray survey of ULIRGsApr 29 2003XMM-Newton observations of 10 ULIRGs are reported. The aim is to investigate in hard X-rays a complete ULIRG sample selected from the bright IRAS 60$\mu$m catalogue. All sources are detected in X-rays, 5 of which for the first time. These observations ... More
XMM-Newton observations of ULIRGs I: A Compton-thick AGN in IRAS19254-7245Nov 12 2002We present the XMM-Newton observation of the merging system IRAS 19254-7245, also known as The Superantennae, whose southern nucleus is classified as a Seyfert 2 galaxy. The XMM-Newton data have allowed us to perform a detailed X-ray imaging and spectral ... More
Multiwavelength campaign on Mrk 509. XVI. Continued HST/COS monitoring of the far-ultraviolet spectrumJan 22 2019To elucidate the location, physical conditions, mass outflow rate, and kinetic luminosity of the outflow from the active nucleus of the Seyfert 1 galaxy Mrk 509 we used coordinated ultraviolet and X-ray spectral observations in 2012 to follow up our lengthier ... More
An XMM-Newton Survey of Ultra-Luminous Infrared GalaxiesFeb 19 2002We present preliminary results of XMM-Newton observations of 5 Ultra-luminous Infrared Galaxies (ULIRGs), part of a mini-survey program dedicated to 10 ULIRGs selected from the bright IRAS sample. For 3 of them (IRAS 20551-4250, IRAS 19254-7245 and Mkn ... More
High-energy monitoring of Seyfert galaxies: the case of NGC 4593Oct 07 2015We discuss preliminary results from a joint XMM-Newton and NuSTAR monitoring program on the active galactic nucleus NGC 4593, consisting of 5x20 ks observations, spaced by two days, performed in January 2015. The source is found to be variable, both in ... More
A2163: Merger events in the hottest Abell galaxy cluster II. Subcluster accretion with galaxy-gas separationNov 13 2010Located at z = 0.203, A2163 is a rich galaxy cluster with an intra-cluster medium (ICM) that exhibits extraordinary properties, including an exceptionally high X-ray luminosity, average temperature, and a powerful and extended radio halo. The irregular ... More
An enshrouded AGN in the merging starburst system Arp~299 revealed by BeppoSAXNov 05 2002Using a long (=150 ksec), broad-band (0.1--40 keV) BeppoSAX observation of the merging starburst system Arp 299 (=IC 694 + NGC 3690) we found the first unambiguous evidence of the presence of a deeply buried (N_H = 2.5E24 cm-2) AGN having an intrinsic ... More
The complex circumnuclear environment of the broad-line radio galaxy 3C 390.3 revealed by Chandra HETGAug 11 2016We present the first high spectral resolution X-ray observation of the broad-line radio galaxy 3C 390.3 obtained with the high energy transmission grating (HETG) spectrometer on board the Chandra X-ray Observatory. The spectrum shows complex emission ... More
Diffuse Thermal Emission from Very Hot Gas in Starburst GalaxiesAug 27 1999BeppoSAX observations of the nearby archetypical starburst galaxies NGC253 and M82 are presented. Spectral analysis shows that the 2-10 keV spectra of both galaxies, extracted from the central 4' regions, are best fitted by a thermal emission model with ... More
XMM-NEWTON Observation of the Seyfert 2 Galaxy NGC 4138Sep 05 2002The XMM-Newton data presented here are the first X-ray observation of the Seyfert 2 galaxy NGC4138. Although the galaxy has been pointed by ROSAT-HRI, it was not detected, with a flux upper limit of about 1.1x10^-13 erg cm^-2 s^-1 in the 0.2-2.4 keV energy ... More
Feeding and feedback in the powerful radio galaxy 3C 120Mar 01 2017We present the spectral analysis of a 200~ks observation of the broad-line radio galaxy 3C~120 performed with the high energy transmission grating (HETG) spectrometer on board the \emph{Chandra} X-ray Observatory. We find (i) a neutral absorption component ... More
A2163: Merger events in the hottest Abell galaxy cluster I. Dynamical analysis from optical dataDec 17 2007We present a detailed optical analysis of the galaxy cluster A2163 based on new multicolor wide field imaging and medium-to-high resolution (R~2000) spectroscopy. While X-ray observations have revealed that merging processes are present in this cluster, ... More
The nature of the "Composite" Seyfert/Star-forming GalaxiesDec 13 2002Apr 02 2003We present the results obtained with BeppoSAX observations of the three Composite Seyfert/star-forming galaxies: IRAS 20051-1117, IRAS 04392-0123 and IRAS 01072+4954. These sources belong to an enigmatic class of X-ray sources detected in the ROSAT All-Sky ... More
The impact of galaxy interactions on AGN activity in zCOSMOSSep 06 2011Close encounters between galaxies are expected to be a viable mechanism, as predicted by numerical simulations, by which accretion onto supermassive black holes can be initiated. To test this scenario, we construct a sample of 562 galaxies (M*>2.5x10^10 ... More
On the absorption of X-ray bright broad absorption line quasarsSep 04 2008Sep 18 2008Most X-ray studies of BALQSOs found significant (N_H~10^{22-24} cm^{-2}) intrinsic column densities of gas absorbing an underlying typical power-law continuum emission, in agreement with expectations from radiatively driven accretion disk wind models. ... More
Outflows and winds in AGNs: a case for Simbol-XDec 18 2007Chandra and XMM-Newton X-ray observations are accumulating evidence for massive, high velocity outflows in Seyfert galaxies and quasars, most likely originating very close to the central supermassive black hole. These results are offering new potential ... More
BeppoSAX observations of bright Seyfert 2 galaxiesJan 12 1999We report on BeppoSAX broad band (0.1-100 keV) observations of bright Seyfert 2 galaxies and discuss the results in the framework of the unified theory of AGNs. The data are used to probe Nh distribution in type 2 objects and to identify heavily absorbed ... More
Ultra-fast outflows (aka UFOs) from AGNs and QSOsJan 30 2013During the last decade, strong observational evidence has been accumulated for the existence of massive, high velocity winds/outflows (aka Ultra Fast Outflows, UFOs) in nearby AGNs and in more distant quasars. Here we briefly review some of the most recent ... More
Diffuse Thermal Emission from Very Hot Gas in Starburst Galaxies: Spatial ResultsFeb 01 1999New BeppoSAX observations of the nearby prototypical starburst galaxies NGC 253 and M82 are presented. A companion paper (Cappi et al. 1998;astro-ph/9809325) shows that the hard (2-10 keV) spectrum of both galaxies, extracted from the source central regions, ... More
NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814Sep 21 2017Oct 08 2017We report on the NuSTAR observations of two bright Seyfert 1 galaxies, namely MCG +8-11-11 (100 ks) and NGC 6814 (150 ks). The main goal of these observations was to investigate the Comptonization mechanisms acting in the innermost regions of AGN which ... More
Radio/X-ray monitoring of the broad-line radio galaxy 3C 382. High-energy view with XMM-Newton and NuSTARMay 16 2018We present the analysis of five joint XMM-Newton/NuSTAR observations, 20 ks each and separated by 12 days, of the broad-line radio galaxy 3C 382. The data were obtained as part of a campaign performed in September-October 2016 simultaneously with VLBA. ... More
Diffuse Thermal Emission from Very Hot Gas in Starburst Galaxies: Spectral ResultsSep 25 1998New BeppoSAX observations of the nearby archetypical starburst galaxies (SBGs) NGC253 and M82 are presented. The main observational result is the unambiguous evidence that the hard (2-10 keV) component is (mostly) produced in both galaxies by thermal ... More
BeppoSAX detection of the Fe K line in the starburst galaxy NGC253Jan 14 1998Preliminary results obtained from BeppoSAX observation of the starburst galaxy NGC253 are presented. X-ray emission from the object is clearly extended but most of the emission is concentrated on the optical nucleus. Preliminary analysis of the LECS and ... More
BeppoSAX detection of the Fe K line in the nearby starburst galaxy NGC 253Sep 21 1998We present BeppoSAX results on the nearby starburst galaxy NGC 253. Although extended, a large fraction of the X-ray emission comes from the nuclear region. Preliminary analysis of the LECS/MECS/PDS ~0.2-60 keV data from the central 4' region indicates ... More
BeppoSAX uncovers the hidden Seyfert 1 nucleus in the Seyfert 2 galaxy NGC 2110Jan 12 1999The Seyfert 2 galaxy NGC 2110 has been observed with BeppoSAX between 0.5 and 150 keV. The high energy instrument onboard, PDS, has succeeded in measuring for the first time the spectrum of this source in the 13-150 keV range. The PDS spectrum, having ... More
Bias in the Estimation of Global Luminosity FunctionsFeb 09 2004We discuss a bias present in the calculation of the global luminosity function (LF) which occurs when analysing faint galaxy samples. This effect exists because of the different spectral energy distributions of galaxies, which are in turn quantified by ... More
The ESO Slice Project (ESP) galaxy redshift survey: I. Description and First ResultsApr 11 1997The ESO Slice Project (ESP) is a galaxy redshift survey we have recently completed as an ESO Key-Project. The ESP covers 23.3 square degrees in a region close to the South Galactic Pole. The survey is nearly complete (85%) to the limiting magnitude b_J=19.4 ... More
A BeppoSAX observation of 3C273: broadband spectrum and detection of a low-energy absorption featureJul 07 1997We report the results of a 3C273 observation performed during the Science Verification Phase (SVP) of the BeppoSax satellite. The broad-band spectrum is well represented by a power-law between 1 keV and 200 keV. The spectral slope is flat (\Gamma ~1.6) ... More
The ESO Slice Project (ESP) galaxy redshift survey: II. The luminosity function and mean galaxy densityMay 13 1997(Abridged) The ESO Slice Project (ESP) is a galaxy redshift survey we have completed as an ESO Key-Project over ~23 square degrees, in a region near the South Galactic Pole. The survey is nearly complete to the limiting magnitude b_J=19.4 and consists ... More
XMM-Newton observations of NGC 253: Resolving the emission components in the disk and nuclear areaOct 30 2000The high XMM-Newton throughput allows a detailed investigation of the spatial, spectral and variability properties of the extended and point source emission of the starburst galaxy NGC 253 simultaneously. We characterize the brightest sources by their ... More