A5026031896- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Mechanics and Biomechanics Studies
- Particle Detector Development and Performance
- High-pressure geophysics and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Adaptive optics and wavefront sensing
- Scientific Measurement and Uncertainty Evaluation
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Nuclear Physics and Applications
- History and Developments in Astronomy
- Dark Matter and Cosmic Phenomena
- Atomic and Molecular Physics
- Calibration and Measurement Techniques
Roma Tre University
2015-2024
Institute for Space Astrophysics and Planetology
2023-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Torino
2021-2024
University of Turin
2024
Kavli Institute for Particle Astrophysics and Cosmology
2024
Agenzia Spaziale Italiana
2024
Marshall Space Flight Center
2019-2021
University of Pisa
2021
Pennsylvania State University
2018
California Institute of Technology
2018
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates band from 3 to 79 keV, extending sensitivity of far beyond ∼10 keV cutoff achieved by all previous satellites. inherently low background associated with concentrating light enables probe hard sky a more than 100-fold improvement over collimated or coded mask instruments that have operated this bandpass. Using its unprecedented...
We present and discuss a "3-dimensional" diagnostic diagram for Seyfert2 galaxies obtained by means of X-ray [OIII] data on large sample objects (reported in the Appendix). The shows Kalpha iron line equivalent width as function both column density derived from photoelectric cutoff 2-10 keV flux normalized to optical (the latter corrected extinction assumed be true indicator source intrinsic luminosity). find that hard properties type 2 depend single parameter, absorbing along sight,in...
We present the first set of XMM-Newton EPIC observations in 2 square degree COSMOS field. The strength project is unprecedented combination a large solid angle and sensitivity over whole multiwavelength spectrum. are very efficient localizing identifying active galactic nuclei (AGN) clusters as well groups galaxies. One primary goals Cosmos survey to study co-evolution function their environment Cosmic web. Here we log observations, images summary research highlights for pass 25 pointings...
The evolution of galaxies is connected to the growth supermassive black holes in their centers. During quasar phase, a huge luminosity released as matter falls onto hole, and radiation-driven winds can transfer most this energy back host galaxy. Over five different epochs, we detected signatures nearly spherical stream highly ionized gas broadband x-ray spectra luminous PDS 456. This persistent wind expelled at relativistic speeds from inner accretion disk, its wide aperture suggests an...
Launched on 2021 December 9, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Mission in collaboration with Italian Space Agency (ASI). The mission will open new window of investigation—imaging x-ray polarimetry. observatory features three identical telescopes, each consisting mirror module assembly polarization-sensitive imaging detector at focus. A coilable boom, deployed orbit, provides necessary 4-m focal length. utilizes three-axis-stabilized spacecraft, which services such...
Supermassive black holes in the nuclei of active galaxies expel large amounts matter through powerful winds ionized gas. The archetypal galaxy NGC 5548 has been studied for decades, and high-resolution X-ray UV observations have previously shown a persistent outflow. An observing campaign 2013 with six space observatories shows nucleus to be obscured by long-lasting, clumpy stream gas never seen before. It blocks 90% soft emission causes simultaneous deep, broad absorption troughs. outflow...
XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to Astronomy. At time of writing XIPE in competitive phase A as fourth medium size ESA (M4). It promises reopen polarimetry window high energy Astrophysics after more than 4 decades thanks detector that efficiently exploits photoelectric effect and optics with large effective area. uniqueness time-spectrally-spatially- resolved breakthrough astrophysics fundamental physics. Indeed payload consists three Gas Pixel Detectors...
The Imaging X-ray Polarimetry Explorer (IXPE) expands observation space by simultaneously adding polarization measurements to the array of source properties currently measured (energy, time, and location). IXPE will thus open new dimensions for understanding how emission is produced in astrophysical objects, especially systems under extreme physical conditions—such as neutron stars black holes. Polarization singularly probes anisotropies—ordered magnetic fields, aspheric matter...
While X-ray Spectroscopy, Timing and Imaging have improved verymuch since 1962, when the first astronomical non-solar source was discovered, especially with launch of Newton/X-ray Multi-Mirror Mission, Rossi/X-ray Explorer Chandra/Advanced Astrophysics Facility, progress polarimetry has been meager. This is in part due to lack sensitive polarization detectors, fate approved missions because celestial sources appeared less polarized than expected. Only one positive measurement available until...
A black hole x-ray binary (XRB) system forms when gas is stripped from a normal star and accretes onto hole, which heats the sufficiently to emit x-rays. We report polarimetric observation of XRB Cygnus X-1 using Imaging Polarimetry Explorer. The electric field position angle aligns with outflowing jet, indicating that jet launched inner emitting region. polarization degree (4.01+-0.20)% at 2 8 kiloelectronvolts, implying accretion disk viewed closer edge-on than orbit. observations reveal...
Abstract Most of the light from blazars, active galactic nuclei with jets magnetized plasma that point nearly along line sight, is produced by high-energy particles, up to around 1 TeV. Although are known be ultimately powered a supermassive black hole, how particles accelerated such high energies has been an unanswered question. The process must related magnetic field, which can probed observations polarization jets. Measurements radio optical polarization—the only range available until...
ABSTRACT We present an X-ray spectropolarimetric analysis of the bright Seyfert galaxy NGC 4151. The source has been observed with Imaging Polarimetry Explorer (IXPE) for 700 ks, complemented simultaneous XMM–Newton (50 ks) and NuSTAR (100 pointings. A polarization degree Π = 4.9 ± 1.1 per cent angle Ψ 86° 7° east north (68 confidence level) are measured in 2–8 keV energy range. shows that could be entirely due to reflection. Given low reflection flux IXPE band, this requires, however, a...
Abstract We report on an observational campaign the bright black hole (BH) X-ray binary Swift J1727.8–1613 centered around five observations by Imaging Polarimetry Explorer. These track for first time evolution of polarization a BH across hard to soft state transition. The 2–8 keV degree decreased from ∼4% ∼3% observations, but angle remained oriented in north–south direction throughout. Based with Australia Telescope Compact Array, we find that intrinsic 7.25 GHz radio aligns polarization....
Abstract Black hole X-ray binaries exhibit different spectral and timing properties in accretion states. The outburst of a recently discovered extraordinarily bright source, Swift J1727.8–1613, has enabled the first investigation how polarization source evolve with state. 2–8 keV degree was previously measured by Imaging Polarimetry Explorer (IXPE) to be ≈4% hard intermediate Here we present new IXPE results taken soft state, flux dominated thermal disk emission. We find that dropped...
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...
The presence of an obscuring torus around the nucleus a Seyfert galaxy, as supposed in popular unification scheme, can strongly modify X-ray spectrum for both type 1 and 2 galaxies. We study this problem by means Monte Carlo simulations, finding that, if is Compton-thick, it scatter at small angles significant fraction nuclear radiation, contribute to continuum galaxies above ∼ 10 keV, fluorescence iron line 6.4 keV. At large inclination column densities, attenuated photoabsorption Compton...
We discuss the X-ray properties of 49 local () Seyfert 2 galaxies with HST/WFC2 high-resolution optical coverage. It includes results 26 still unpublished Chandra and XMM-Newton observations, which yield 25 (22) new detections in 0.5–2 keV (2–10 keV) energy band. Our sample covers a range 2–10 observed flux, F2-10, from to erg cm-2 s-1. The percentage objects that are likely obscured by Compton-thick matter (column density, cm-2) is 50%, reaches 80% for . Hence, Kα fluorescent iron lines...
Hard X-ray radiation has been detected for the first time in Coma cluster by BeppoSAX. Thanks to unprecedented sensitivity of Phoswich Detection System (PDS) instrument, source up ~80 keV. There is clear evidence (4.5 sigma) non-thermal emission excess thermal above ~25 The hard very unlikely due X Comae, Seyfert 1 galaxy present field view PDS. A spectral tail inverse Compton on CMB photons predicted clusters, like Coma, with radio halos. Combining results observations, a volume-averaged...
We discuss the properties of a small sample type 2 Seyfert galaxies whose X-ray spectra changed appearance on time-scales years, becoming reflection-dominated from Compton-thin, or vice versa. A spectrum is usually taken as evidence Compton-thick absorption, but we instead argue that such due to temporary switching-off nuclear radiation. The observations discussed here may help explain mismatches between optical and classifications, provide new strong direct for presence more than one cold...
<i>Aims. <i/>We present CAIXA, a Catalogue of AGN In the <i>XMM-Newton<i/> Archive. It consists all radio-quiet X-ray unobscured ( cm<sup>-2<sup/>) active galactic nuclei (AGN) observed by in targeted observations, whose data are public as March 2007. With its 156 sources, this is largest catalogue high signal-to-noise spectra AGN.<i>Methods. <i/>All EPIC pn sources CAIXA were extracted homogeneously, and baseline model was applied order to derive their basic properties. These complemented...
We present results from the photometric and spectroscopic identification of 122 X-ray sources recently discovered by XMM-Newton in 2-10 keV band (the HELLAS2XMM 1dF sample). Their flux cover range 8E-15-4E-13 cgs total area surveyed is 0.9 deg2. About 20% hard selected have an to optical ratio (X/O) ten times or more higher than that optically AGN. Unlike faint found ultra-deep Chandra surveys, which reach (and optical) fluxes one order magnitude lower survey sources, many extreme X/O our...
We report on the results of first XMM systematic "excess variance" study all radio quiet, X-ray un-obscured AGN. The entire sample consist 161 sources observed by for more than 10 ks in pointed observations which is largest used so far to AGN variability time scales less a day. compute excess variance AGN, different time-scales (10, 20, 40 and 80 ks) energy bands (0.3-0.7, 0.7-2 2-10 keV). observe highly significant tight (~0.7 dex) correlation between MBH. subsample reverberation mapped...
The X-ray spectra of many active galactic nuclei (AGNs) show a soft excess below 1–2 keV on top the extrapolated high-energy power law. origin this component is uncertain. It could be signature relativistically blurred, ionized reflection or tail thermal Comptonization in warm ( kT ~ 1 keV), optically thick τ ≃ 10–20) corona producing optical/UV to emission. purpose present paper test model statistically significant sample unabsorbed, radio-quiet AGNs with XMM-Newton archival data, providing...
<i>Context. <i/>There have been recent claims that a significant fraction of type 2 AGN accrete close to or even above the Eddington limit. In AGN, bolometric luminosity (<i>L<i/><sub>b<sub/>) is generally inferred from [OIII] emission line (<i>L<i/><sub>OIII<sub/>). The key issue in estimating these therefore know correction be applied <i>L<i/><sub>OIII<sub/>. A complication arises observed <i>L<i/><sub>OIII<sub/> being affected by extinction, most likely dust within narrow region....