C. Vignali
A5026515938- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Adaptive optics and wavefront sensing
- Particle Detector Development and Performance
- Calibration and Measurement Techniques
- Advanced X-ray Imaging Techniques
- History and Developments in Astronomy
- Relativity and Gravitational Theory
- Geophysics and Gravity Measurements
- Particle Accelerators and Free-Electron Lasers
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Mechanics and Biomechanics Studies
- Solar and Space Plasma Dynamics
University of Bologna
2016-2025
Osservatorio di Astrofisica e Scienza dello Spazio
2018-2024
Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna
2009-2024
Istituto di Radioastronomia di Bologna
2021-2023
Osservatorio astronomico di Bologna
2011-2022
National Institute for Astrophysics
2003-2022
European Organization for Nuclear Research
2022
Arcetri Astrophysical Observatory
2017
Sapienza University of Rome
2009-2015
Brera Astronomical Observatory
2010-2015
We present catalogs for the ~2 Ms Chandra Deep Field-North, currently deepest X-ray observation of Universe in 0.5-8.0 keV band. Five hundred and three (503) sources are detected over an ~448 sq.arcmin area up to seven bands; 20 these lie Hubble Field-North. Source positions determined using matched-filter centroiding techniques; median positional uncertainty is ~0.3 arcsecs. The colors indicate a broad variety source types, although absorbed AGNs (including some possible Compton-thick...
We present partial-correlation analyses that examine the strengths of relationships between l2500 Å, l2 keV, αOX, and redshift for optically selected active galactic nuclei (AGNs). extend work Strateva coworkers, which analyzed AGNs from Sloan Digital Sky Survey (SDSS), by including 52 moderate-luminosity, COMBO-17 survey with corresponding deep (≈250 ks to 1 Ms) X-ray observations Extended Chandra Deep Field-South. The extends ∼3 mag deeper than SDSS probes moderate-luminosity numerically...
The COSMOS-Legacy survey is a 4.6 Ms Chandra program that has imaged 2.2 deg$^2$ of the COSMOS field with an effective exposure $\simeq$160 ks over central 1.5 and $\simeq$80 in remaining area. combination 56 new observations, obtained as X-ray Visionary Project, previous C-COSMOS survey. We describe reduction analysis observations properties 2273 point sources detected above spurious probability 2$\times 10^{-5}$. also present updated data. whole includes 4016 (3814, 2920 2440 full, soft...
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra} program that has imaged the central 0.5 sq.deg of field (centered at 10h, +02deg) with an effective exposure ~160ksec, and outer 0.4sq.deg. area ~80ksec. limiting source detection depths are 1.9e-16 erg cm(-2) s(-1) in Soft (0.5-2 keV) band, 7.3e(-16) cm^-2 s^-1 Hard (2-10 5.7e(-16) Full (0.5-10 band. Here we describe strategy, design execution C-COSMOS survey, present catalog 1761 point sources detected probability being...
Bolometric luminosities and Eddington ratios of both X-ray selected broad-line (Type-1) narrow-line (Type-2) AGN from the XMM-Newton survey in COSMOS field are presented. The sample is composed by 929 (382 Type-1 547 Type-2 AGN) it covers a wide range redshifts, absorbing column densities. About 65% sources spectroscopically identified as either or (83% 52% respectively), while accurate photometric redshifts available for rest sample. study such large with high quality multi-wavelength...
We present new photometry of 16 local Seyferts including 6 Compton-thick sources in <i>N<i/>-band filters around 12-<i>μ<i/>m, obtained with the VISIR instrument on 8-m Very Large Telescope. The near-diffraction-limited imaging provides least-contaminated core fluxes for these to date. Augmenting our previous observations and published intrinsic X-ray fluxes, we form a total sample 42 which find strong mid-infrared:X-ray (12.3 <i>μ<i/>m:2–10 keV) luminosity correlation. Performing...
We report the final optical identifications of medium-depth (∼60 ks), contiguous (2 deg2) XMM-Newton survey COSMOS field. has detected ∼1800 X-ray sources down to limiting fluxes ∼5 × 10−16, ∼3 10−15, and ∼7 10−15 erg cm−2 s−1 in 0.5–2 keV, 2–10 5–10 keV bands, respectively (∼1 ∼6 ∼1 10−14 s−1, three respectively, over 50% area). The work is complemented by an extensive collection multiwavelength data from 24 μm UV, available survey, for each sources, including spectroscopic redshifts ≳50%...
We present the XXL Survey, largest XMM programme totaling some 6.9 Ms to date and involving an international consortium of roughly 100 members. The Survey covers two extragalactic areas 25 deg2 each at a point-source sensitivity ~ 5E-15 erg/sec/cm2 in [0.5-2] keV band (completeness limit). survey's main goals are provide constraints on dark energy equation state from space-time distribution clusters galaxies serve as pathfinder for future, wide-area X-ray missions. review science objectives,...
In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of Cosmic Evolution Survey (COSMOS) field. The availability a large training set spectroscopic that extends faint magnitudes enabled comparable highest quality results presently available normal galaxies. We demonstrate morphologically extended, X-ray without optical variability are more accurately described by library galaxies (corrected emission lines) than active...
The ionising continuum from active galactic nuclei (AGN) is fundamental for interpreting their broad emission lines and understanding impact on the surrounding gas. Furthermore, it provides hints how matter accretes onto supermassive black holes. Using HST's Wide Field Camera 3 we have constructed first stacked ultraviolet (rest-frame wavelengths 600-2500Å) spectrum of 53 luminous quasars at z=2.4, with a state-of-the-art correction intervening Lyman forest absorption. slope ($f_ν\propto...
The AGN bolometric correction is a key element to understand BH demographics and compute accurate accretion histories from luminosities. However, current estimates still differ each other by up factor of two three, rely on extrapolations at the lowest highest Here we revisit this fundamental issue presenting general hard X-ray ($K_{X}$) optical ($K_{O}$) corrections, computed combining several samples spanning widest (about 7 dex) luminosity range ever used for kind studies. We analysed...
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, program that has imaged the central 0.9 deg2 of field down to limiting depths 1.9 × 10−16 erg cm−2 s−1 in soft (0.5–2 keV) band, 7.3 hard (2–10 and 5.7 full (0.5–10 band. In this paper we report i, K, 3.6 μm identifications 1761 X-ray point sources. We use likelihood ratio technique derive association optical/infrared counterparts for 97% For most remaining 3%, presence multiple or faintness possible counterpart prevented unique...
ABSTRACT We present the catalog of optical and infrared counterparts Chandra COSMOS-Legacy Survey, a 4.6 Ms program on 2.2 deg 2 COSMOS field, combination 56 new overlapping observations obtained in Cycle 14 with previous C-COSMOS survey. In this Paper we report i , K 3.6 μ m identifications 2273 X-ray point sources detected observations. use likelihood ratio technique to derive association optical/infrared (IR) for 97% sources. also update information 1743 C-COSMOS, using not available when...
Abstract The Lunar Gravitational-wave Antenna (LGWA) is a proposed array of next-generation inertial sensors to monitor the response Moon gravitational waves (GWs). Given size and expected noise produced by lunar seismic background, LGWA would be able observe GWs from about 1 mHz Hz. This make missing link between space-borne detectors like LISA with peak sensitivities around few millihertz future terrestrial Einstein Telescope or Cosmic Explorer. In this article, we provide first...
<ns4:p>The study of transient and variable events, including novae, active galactic nuclei, black hole binaries, has historically been a fruitful path for elucidating the evolutionary mechanisms our universe. The such events in millimeter submillimeter is, however, still its infancy. Submillimeter observations probe variety materials, as optically thick dust, which are hard to other wavelengths. sensitive number emission mechanisms, from aforementioned cold hot free-free emission,...
We have determined the cosmological evolution of density active galactic nuclei (AGNs) and their NH distribution as a function unabsorbed 2-10 keV luminosity up to redshift 4. used HELLAS2XMM sample combined with other published catalogs, yielding total 508 AGNs. Our best fit is obtained luminosity-dependent (LDDE) model where low-luminosity (LX ~ 1043 ergs s-1) AGNs peak at z 0.7, while high-luminosity > 1045 2.0. A pure (PLE) can instead be rejected. There evidence that fraction absorbed...
Using a sample of 228 optically selected Active Galactic Nuclei (AGNs) in the 0.01-6.3 redshift range with high fraction X-ray detections (81-86%), we study relation between rest-frame UV and soft emission its evolution cosmic time. The majority AGNs our (155 objects) have been from Sloan Digital Sky Survey (SDSS) an unbiased way, rendering results representative all SDSS AGNs. addition two heterogeneous samples 36 high-redshift 37 low-redshift further supports extends conclusions. We...
<i>Context. <i/>The COSMOS survey is a multiwavelength aimed to study the evolution of galaxies, AGN and large scale structures. Within this XMM-COSMOS powerful tool detect galaxy clusters. The deep X-ray over full 2 deg<sup>2<sup/> area. It consists 55 XMM-<i>Newton<i/> pointings for total exposure ~1.5 Ms with an average vignetting-corrected depth 40 ks across field view sky coverage 2.13 deg<sup>2<sup/>.<i>Aims. <i/>We present catalogue point-like sources detected EPIC CCD cameras,...
We present point-source catalogs for the ~2 Ms exposure of Chandra Deep Field-South (CDF-S); this is one two most-sensitive X-ray surveys ever performed. The survey covers an area ~436 arcmin^2 and reaches on-axis sensitivity limits ~1.9x10^{-17} ~1.3x10^{-16} ergs/cm^2/s 0.5-2.0 2-8 keV bands, respectively. Four hundred sixty-two point sources are detected in at least three bands that were searched; 135 these new compared to previous ~1 CDF-S detections. Source positions determined using...
We investigate the X-ray properties of color-selected radio-quiet quasars (RQQs) in Sloan Digital Sky Survey (SDSS) Early Data Release using ROSAT, Chandra, and XMM-Newton data. In 0.16-6.28 redshift range, 136 RQQs have detections (69 from ROSAT All-Sky Survey, RASS), while for 70 upper limits are obtained. The well-defined selection method utilized by SDSS, coupled with tight radio constraints FIRST/NVSS surveys, allow us to define a representative sample optically selected whose...
The COSMOS survey is a multiwavelength aimed to study the evolution of galaxies, AGN and large scale structure. XMM-COSMOS deep X-ray over full 2 deg2 area. It consists 55 XMM-Newton pointings for total exposure ~1.5 Ms with an average vignetting corrected depth 40 ks across field view sky coverage 2.13 deg2. We present catalogue point-like sources detected EPIC CCD cameras, logN-logS relations colour-colour diagrams. analysis was performed in 0.5-2 keV, 2-10 keV 5-10 energy bands....
We present Chandra point-source catalogs for the Extended Deep Field-South (E-CDF-S) survey. The E-CDF-S consists of four contiguous 250 ks observations covering an approximately square region total solid angle ≈0.3 deg2, which flank existing ≈1 Ms (CDF-S). survey reaches sensitivity limits ≈1.1 × 10-16 and ≈6.7 ergs cm-2 s-1 0.5-2.0 2-8 keV bands, respectively. detect 762 distinct X-ray point sources within exposure; 589 these are new (i.e., not previously detected in CDF-S). This brings...
We present a study of the host galaxies AGN selected from zCOSMOS survey to establish if accretion onto supermassive black holes and star formation are explicitly linked up z~1. identify 152 that harbor AGN, based on XMM observations 7543 (i<22.5). Star rates (SFRs), including those weighted by stellar mass, determined using [OII]3727 emission-line, corrected for an contribution. find majority hosts have significant levels with distribution spanning ~1-100 Msun yr^-1. The close association...