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Related papers: The BeppoSAX 1-8 keV cosmic background spectrum

200 papers

We present a study of the source positioning accuracy of the LECS and MECS instruments on-board BeppoSAX. From the analysis of a sample of archival images we find that a systematic error, which depends on the spacecraft roll angle and has…

Astrophysics · Physics 2009-11-07 M. Perri , M. Capalbi

We have obtained the average 1--500 keV spectrum of radio-quiet Seyfert 1s using data from EXOSAT, Ginga, HEAO, and GRO/OSSE. The spectral fit to the combined average EXOSAT and OSSE data is fully consistent with that for Ginga and OSSE,…

The synthesis model for the cosmic X-ray background (XRB) -based on the integrated emission of Active Galactic Nuclei (AGNs)- is complemented with new observational results. We adopt the most recent estimates of the AGN X-ray luminosity…

Astrophysics · Physics 2007-05-23 R. Gilli , G. Risaliti , M. Salvati

The X-ray luminous quasar GB 1428+4217 at redshift 4.72 has been observed with ASCA. The observed 0.5-10 keV flux is 3.2E-12 erg/s/cm2. We report here on the intrinsic 4-57 keV X-ray spectrum, which is very flat (photon index of 1.29). We…

Astrophysics · Physics 2009-10-30 A. C. Fabian , K. Iwasawa , A. Celotti , W. N. Brandt , R. G. McMahon , I. M. Hook

We study the spectral properties of the unresolved cosmic X-ray background (CXRB) in the 1.5-7.0 keV energy band with the aim of providing an observational constraint on the statistical properties of those sources that are too faint to be…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 A. Moretti , S. Vattakunnel , P. Tozzi , R. Salvaterra , P. Severgnini , D. Fugazza , F. Haardt , R. Gilli

From past experiments the average power density spectrum (PDS) of GRBs with unknown redshift was found to be modelled from 0.01 to 1 Hz with a power-law, f^(-alpha), with alpha broadly consistent with 5/3. Recent analyses of the Swift/BAT…

High Energy Astrophysical Phenomena · Physics 2015-06-15 S. Dichiara , C. Guidorzi , L. Amati , F. Frontera

GRS 1758-258 is one of the few persistent hard X-ray emitters (E>100 keV) in the Galaxy. Using the ASCA satellite, we have obtained the first detailed data on GRS 1758-258 in the 1-10 keV range, where previous observations were affected by…

Astrophysics · Physics 2009-10-28 S. Mereghetti , D. I. Cremonesi , F. Haardt , T. Murakami , T. Belloni , A. Goldwurm

The integrated emission of highly obscured AGN is expected to provide a major contribution to the X-ray energy density in the Universe: the X-ray background (XRB). The study of these objects is possible only at energies where the effects of…

Astrophysics · Physics 2007-05-23 A. Comastri , F. Fiore , C. Vignali , F. La Franca , G. Matt

We report the results of a cosmic shear survey using the 4.2m William Herschel Telescope on La Palma, to a depth of R=25.8 (z~0.8), over 4 square degrees. The shear correlation functions are measured on scales from 1' to 15', and are used…

The energy spectrum of cosmic-ray antiprotons from 0.17 to 3.5 GeV has been measured using 7886 antiprotons detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This…

We report on the BeppoSAX observations of the gamma-ray blazar PKS 0528+134 performed in Feb and Mar 1997, during a multiwavelength campaign involving EGRET and ground based telescopes. The source was in a faint and hard state, with energy…

We present a comprehensive analysis of Chandra X-ray observations of 15 young radio quasars at redshifts $4.5 < z < 5.0$. All sources are detected in the $0.5-7.0$ keV energy band. Emission spectra are extracted, and the average photon…

We present two BeppoSAX observations of BL Lac (2200+420) as part of a multiwavelength campaign performed in 2000. The source was in different states of activity: in June, the X-ray spectrum was faint and hard (alpha sim 0.8), with positive…

Astrophysics · Physics 2009-11-10 M. Ravasio , G. Tagliaferri , G. Ghisellini , F. Tavecchio , M. Boettcher , M. Sikora

We present BeppoSAX observations of three gamma-ray emitting quasars, namely 0836+710, 1510-089 and 2230+114. The three objects have been detected up to 100 keV showing extremely flat power-law spectra above 2 keV (energy index…

The transient 500 s X-ray pulsar MAXI J1409-619 was discovered by the slit cameras aboard MAXI on October 17, 2010, and soon after accurately localized by Swift. We found that the source position was serendipitously observed in 2000 during…

High Energy Astrophysical Phenomena · Physics 2015-03-17 Mauro Orlandini , Filippo Frontera , Nicola Masetti , Vito Sguera , Lara Sidoli

We present the first results using the Reuven Ramaty High-Energy Solar Spectroscopic Imager, RHESSI, to observe solar X-ray emission not associated with active regions, sunspots or flares (the quiet Sun). Using a newly developed chopping…

Astrophysics · Physics 2008-11-26 Iain G. Hannah , G. J Hurford , H. S. Hudson , R. P. Lin , K. van Bibber

We report the hard X-ray spectrum of the Coma cluster obtained using the PDS data of two independent BeppoSAX observations performed with a time interval of about three years. In both the spectra a non thermal excess with respect to the…

We present a new local interstellar spectrum for cosmic ray electrons over an energy range from 1 MeV to 70 GeV. Below (0.8 plus minus 0.2) GeV it has a power law form, E^-(1.55 plus minus 0.05), with E kinetic energy, which is consistent…

Solar and Stellar Astrophysics · Physics 2013-08-12 M. S. Potgieter , E. E. Vos , R. R. Nndanganeni , M. Boezio , R. Munini