A5052348855- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Particle Detector Development and Performance
- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Calibration and Measurement Techniques
- Advanced X-ray Imaging Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- Nuclear Physics and Applications
- Particle physics theoretical and experimental studies
- Scientific Measurement and Uncertainty Evaluation
- Superconducting and THz Device Technology
- Dark Matter and Cosmic Phenomena
- Spectroscopy and Laser Applications
Astronomical Observatory of Rome
2015-2024
National Institute for Astrophysics
2012-2024
Xiamen University
2022-2024
Center for Astrophysics Harvard & Smithsonian
2010-2020
Astronomical Observatory
2020
The Ohio State University
2008-2017
University of Crete
2010-2017
University of Geneva
2016
Instituto de Astrofísica de Andalucía
2016
Ospedale Pediatrico Giovanni XXIII
2016
The CIAO (<i>Chandra</i> Interactive Analysis of Observations) software package was first released in 1999 following the launch <i>Chandra</i> X-ray Observatory and is used by astronomers across world to analyze data as well from other telescopes. From earliest design discussions, planned a general-purpose scientific analysis system optimized for astronomy, consists mainly command line tools (allowing easy pipelining scripting) with parameter-based interface layered on flexible manipulation...
The X-ray Integral Field Unit (X-IFU) is the high resolution spectrometer of ESA Athena observatory. Over a field view 5' equivalent diameter, it will deliver spectra from 0.2 to 12 keV with spectral 2.5 eV up 7 on ∼ 5" pixels. X-IFU based large format array super-conducting molybdenum-gold Transition Edge Sensors cooled at 90 mK, each coupled an absorber made gold and bismuth pitch 249 μm. A cryogenic anti-coincidence detector located underneath prime TES enables non background be reduced....
We present a study of the variations in absorbing column density 25 X-ray-defined Seyfert 2 galaxies, as inferred from hard X-ray observations, on timescales months to several years. show that significant variation NH (from 20% 80%) is observed almost all (22 25) sources with multiple although absorption never vanishes. For subsample 11 at least five times, typical time, defined by structure function, less than 1 yr for both heavily absorbed (NH ~ 1023 cm-2) and moderately 1022 sources....
We present the first X-ray detection of resonant absorption from warm/hot local gas either in our Galaxy, or intergalactic space surrounding along line sight toward blazar PKS 2155-304. The Chandra HRCS/LETG spectrum this z = 0.116 source clearly shows, at ≥5 σ level, unresolved (FWHM ≤ 800 km s-1 a 2 confidence level) O VII Kα and Ne IX lines 21.603 13.448 Å (i.e., cz 14 rest frame, line). VIII Kβ same system are also detected lower significance level ~3 σ), while upper limits set on Kβ, X...
We present a model that relates the width of broad emission lines active galactic nuclei (AGNs) to Keplerian velocity an accretion disk at critical distance from central black hole. This falls in region bounded on inward side by transition radius between radiation pressure- and gas pressure-dominated outward maximum below which stabilizing, radially accreting vertically outflowing corona exists. show framework this picture, observed range Hβ FWHMs broad-line narrow-line type 1 AGNs is well...
Deep Chandra Low Energy Transmission Grating and High Resolution Camera spectroscopic observations of the isolated neutron star candidate RX J1856.5-3754 have been analyzed to search for metallic resonance cyclotron spectral features pulsation behavior. As found from earlier observations, X-ray spectrum is well represented by an ~60 eV (7 × 105 K) blackbody. No unequivocal evidence line or edge has found, arguing against metal-dominated models. The data contain no pulsation, we place a 99%...
(Abridged) Using a 100 ks XMM-Newton exposure of NGC 4051, we show that the time evolution ionization state X-ray absorbers in response to rapid and highly variable continuum constrains all main physical geometrical properties an AGN Warm Absorber wind. The absorber consists two different components. By tracking opacity gas each component changes ionizing continuum, were able constrain electron density system. measured densities require high low absorbing components 4051 must be compact, at...
Most of the baryons from galaxies have been "missing" and several studies attempted to map circumgalactic medium (CGM) in their quest. We report on X-ray observations made with Chandra X-Ray Observatory probing warm-hot phase CGM our Milky Way at about 106 K. detect O vii viii absorption lines z = 0 extragalactic sight measure accurate column densities using both Kα Kβ vii. then combine these measurements emission Galactic halo literature derive density path length CGM. show that is massive,...
We present the first results of spectroscopy distant, obscured AGN as obtained with ultra-deep (~3.3 Ms) XMM-Newton survey in Chandra Deep Field South (CDFS). One primary goals project is to characterize X-ray spectral properties and heavily Compton-thick over range redhifts luminosities that are relevant terms their contribution background. The exposure, coupled XMM detector's throughput, allowed us accumulate good quality spectra for a large number sources and, particular, at cosmological...
The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution spectroscopy from 0.2 to 12 keV, with 5 arc second pixels over a field of view minute equivalent diameter and spectral resolution 2.5 eV up 7 keV. In this paper, we first review core scientific objectives Athena, driving main performance parameters X-IFU, namely resolution, view, effective area, count rate capabilities, instrumental...
We present a NuSTAR and XMM-Newton monitoring campaign in 2014/2015 of the Compton-thick Seyfert 2 galaxy, NGC 1068. During August 2014 observation, we detect with flux excess above 20 keV ($32\pm6 \%$) respect to December 2012 observation later performed February 2015. do not any spectral variation below 10 data. The transient can be explained by temporary decrease column density obscuring material along line sight (from N$_{\rm H}\simeq10^{25}$ cm$^{-2}$ H}=6.7\pm1.0\times10^{24}$...
We present two Rossi X-Ray Timing Explorer (RXTE) Proportional Counter Array (PCA) observations of the type 2 Seyfert galaxy NGC 4388 caught in an unusual low X-ray absorption state. The were triggered by a detection 1.5-3 keV band RXTE all-sky monitor. was found at somewhat high continuum level [f(2-10 keV) = 8 × 10-11 ergs cm-2 s-1] and with column density NH ~ 3 1022 cm-2, factor ~10 lower than normal. second PCA observation, 4 hr later, gave < 1021 indicating, 3.1 σ level, variability so...
We have used realistic Comptonization models to fit high-quality BeppoSAX data of six Seyfert galaxies. Our main effort was adopt a model taking into account the anisotropy soft photon field. The most important consequence is reduction first scattering order, which produces break (the so-called break) in outgoing spectra. Thus, anisotropic yield spectra with convex curvatures. physical parameters hot corona (i.e., temperature and optical depth) obtained by fitting this class broadband X-ray...
We present a detailed model for the ionized absorbing gas evident in 900 ksec Chandra HETGS spectrum of NGC 3783. The analysis was carried out with PHASE new tool designed to X-ray and UV absorption features plasmas. 0.5-10 keV intrinsic continuum source is well represented by single power law (Gamma=1.53) soft black-body component (kT=10 keV). contains over 100 features, which are fit just six free parameters. consists simple two phase absorber difference 35 ionization parameter 4 column...
The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting more than 1 year and culminating in spring 2005. maximum brightness detected was R = 12.0, which represents the most luminous state thus far observed (M_B ~ -31.4). In order to follow emission behaviour of source detail, a large multiwavelength campaign organized by Whole Earth Blazar Telescope (WEBT). Continuous optical, near-IR monitoring performed several bands. ToO pointings Chandra INTEGRAL satellites provided...
We present the first >=3.5 sigma (conservative) or >=5.8 (sum of lines significance) detection two Warm-Hot Intergalactic Medium (WHIM) filaments at z>0, which we find along line sight to blazar Mkn 421. These systems are detected through highly ionized resonant metal absorption in high quality Chandra-ACIS and -HRC Low Energy Transmission Grating (LETG) spectra 421, obtained following our Target Opportunity requests during outburst phases. The intervening WHIM that detect, have...
We have analyzed the two longest (elapsed time > 3 days) BeppoSAX observations of X-ray brightest Seyfert galaxy, NGC 4151, to search for spectral variability on time-scales from a few tens ksec years. found in both cases highly significant below ~ 6 keV down shortest investigated. These variations can be naturally explained terms low energy cut-off due obscuring matter along line sight. If is modeled by neutral absorption components, one fully covering source and second only fraction...
In the past few years, more and pieces of evidence have been presented for a revision widely accepted unified model active galactic nuclei. A based solely on orientation cannot explain all observed phenomenology. following, we will present that accretion rate is also key parameter presence hidden broad line regions (HBLRs) in Seyfert 2 galaxies. Our sample consists 21 sources with polarized lines 18 without lines. We use stellar velocity dispersions from several studies Ca ii Mg b triplets...
We perform a survey of the X-ray properties 41 objects from WISE/SDSS selected Hyper-luminous (WISSH) quasars sample, composed by 86 broad-line (QSOs) with bolometric luminosity $L_{Bol}\geq 2\times 10^{47}\,erg\, s^{-1}$, at z~2-4. All but 3 QSOs show unabsorbed 2-10 keV luminosities $L_{2-10}\geq10^{45} \,erg \,s^{-1}$. Thanks to their extreme radiative output across Mid-IR-to-X-ray range, WISSH offer opportunity significantly extend and validate existing relations involving $L_{2-10}$....
The so-called jellyfish galaxies are objects exhibiting disturbed morphology, mostly in the form of tails gas stripped from main body galaxy. Several works have strongly suggested ram pressure stripping to be mechanism driving this phenomenon. Here, we focus on one these objects, drawn a sample optically selected galaxies, and use it validate SINOPSIS, spectral fitting code that will used for analysis GASP (GAs Stripping Phenomena with MUSE) survey, study spatial distribution physical...