1,153 research outputs found
INTEGRAL high energy behaviour of 4U 1812-12
The low mass X-ray binary system 4U 1812-12 was monitored with the INTEGRAL
observatory in the period 2003-2004 and with BeppoSAX on April 20, 2000. We
report here on the spectral and temporal analysis of both persistent and burst
emission. The full data set confirms the persistent nature of this burster, and
reveals the presence of emission up to 200 keV. The persistent spectrum is well
described by a comptonization (CompTT) model plus a soft blackbody component.
The source was observed in a hard spectral state with a 1-200 keV luminosity of
2*10^(36) ergs/s and L/LEdd~1% and no meaningful flux variation has been
revealed, as also confirmed by a 2004 RXTE observation. We have also detected 4
bursts showing double peaked profiles and blackbody spectra with temperatures
ranging from 1.9 to 3.1 keV.Comment: 6 pages, 4 figures. Accepted for publication by A&
Swift/XRT follow-up observations of unidentified INTEGRAL/IBIS sources
Many sources listed in the 4th IBIS/ISGRI survey are still unidentified, i.e.
lacking an X-ray counterpart or simply not studied at lower energies (< 10
keV). The cross-correlation between the list of IBIS sources in the 4th
catalogue and the Swift/XRT data archive is of key importance to search for the
X-ray counterparts; in fact, the positional accuracy of few arcseconds obtained
with XRT allows us to perform more efficient and reliable follow-up
observations at other wavelengths (optical, UV, radio). In this work, we
present the results of the XRT observations for four new gamma-ray sources: IGR
J12123-5802, IGR J1248.2-5828, IGR J13107-5626 and IGR J14080-3023. For IGR
J12123-5802 we find a likely counterpart, but further information are needed to
classified this object, IGR J1248.2-5828 is found to be a Seyfert 1.9, for IGR
J13107-5626 we suggest a possible AGN nature, while IGR J14080-3023 is
classified as a Seyfert 1.5 galaxy.Comment: 6 pages, 4 figure and 2 tables. Accepted for publication on PoS
(contribution PoS(extremesky2009)018), proceedings of "The Extreme sky:
Sampling the Universe above 10 keV", held in Otranto (Italy), 13-17 October
200
The XMM Newton and INTEGRAL observations of the supergiant fast X-ray transient IGR J16328-4726
The accretion mechanism producing the short flares observed from the
Supergiant Fast X-ray Transients (SFXT) is still highly debated and forms a
major part in our attempts to place these X-ray binaries in the wider context
of the High Mass X-ray Binaries.
We report on a 216 ks INTEGRAL observation of the SFXT IGR J16328-4726
(August 24-27, 2014) simultaneous with two fixed-time observations with XMM
Newton (33ks and 20ks) performed around the putative periastron passage, in
order to investigate the accretion regime and the wind properties during this
orbital phase. During these observations, the source has shown luminosity
variations, from 4x10^{34} erg/s to 10^{36} erg/s, linked to spectral
properties changes. The soft X-ray continuum is well modeled by a power law
with a photon index varying from 1.2 up to 1.7 and with high values of the
column density in the range 2-4x10^{23}/cm^2. We report on the presence of iron
lines at 6.8-7.1 keV suggesting that the X-ray flux is produced by accretion of
matter from the companion wind characterized by density and temperature
inhomogeneities
Broadband X-ray spectrum of the newly discovered broad line radio galaxy IGR J21247+5058
In this paper we present radio and high energy observations of the INTEGRAL
source IGR J21247+5058, a broad line emitting galaxy obscured by the Galactic
plane. Archival VLA radio data indicate that IGR J21247+5058 can be classified
as an FRII Broad Line Radio Galaxy. The spectrum between 610 MHz and 15 GHz is
typical of synchrotron self-absorbed radiation with a peak at 8 GHz and a low
energy turnover; the core fraction is 0.1 suggestive of a moderate Doppler
boosting of the base of the jet. The high energy broad-band spectrum was
obtained by combining XMM-Newton and Swift/XRT observation with INTEGRAL/IBIS
data. The 0.4-100 keV spectrum is well described by a power law, with slope
=1.5, characterised by complex absorption due to two layers of material
partially covering the source and a high energy cut-off around 70-80 keV.
Features such as a narrow iron line and a Compton reflection component, if
present, are weak, suggesting that reprocessing of the power law photons in the
accretion disk plays a negligible role in the source.Comment: 7 pages, 7 figures, 3 tables, accepted for pubblication on MNRA
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