Related papers: XTE J1906+090: a persistent low luminosity Be X-ra…

To probe further the possible nature of the unidentified source IGR J17098-3628, we have carried out a detailed analysis of its long-term time variability as monitored by RXTE/ASM, and of its hard X-ray properties as observed by INTEGRAL.…

We combine infrared spectra in the I, J, H and K bands together with JHK photometry to characterize the spectral type, luminosity class and distance to the infrared counterparts to five INTEGRAL sources. For SAX J18186-1703 and IGR…

The fourth transient accreting millisecond pulsar XTE J1807-294 was observed during its February/March 2003 outburst by INTEGRAL, partly simultaneously with the XMM-Newton and RXTE satellites. We present here the first study of the 0.5-200…

IGR~J19149+1036 is a high mass X-ray binary detected by INTEGRAL in 2011 in the hard X-ray domain. We have analyzed the BAT survey data of the first 103 months of the Swift mission detecting this source at a significance level of ~30…

We report on the highly variable and erratic long-term X-ray luminosity behavior of the only known accretion-driven millisecond X-ray pulsar SAX J1808.4-3658 during its 2000 outburst, as observed with RXTE. The maximum observed luminosity…

IGR J19140+0951 was discovered by INTEGRAL in 2003 in the 4-100 keV band. Observations with INTEGRAL and RXTE provide a tentative identification as a high-mass X-ray binary (HMXB) with a neutron star as accretor. However, an optical…

IGR J18219-1347 is a hard X-ray source discovered by INTEGRAL in 2010. We have analyzed the X-ray emission of this source exploiting the BAT survey data up to March 2012 and the XRT data that include also an observing campaign performed in…

The hard X-ray source IGRJ11215-5952 has been discovered with INTEGRAL during a short outburst in 2005 and proposed as a new member of the class of supergiant fast X-ray transients. We analysed INTEGRAL public observations of the source…

Four hard X-ray sources from the INTEGRAL and Swift catalogs have been identified. X-ray and optical spectra have been obtained for each of the objects being studied by using data from the INTEGRAL, Swift, ROSAT, and Chandra X-ray…

In this paper we report on the observations performed with INTEGRAL and Swift of the first outburst detected from the hard X-ray transient MAXI J1828-249. During the first about two days of the outburst, the source was observed by MAXI to…

We present timing, spectral, and long-term temporal analysis of the high mass X-ray binary (HMXB) 4U 1036-56 using INTEGRAL and Swift observations. We show that it is a weak hard X-ray source spending a major fraction of the time in…

We present two years of intense Swift monitoring of three SFXTs, IGR J16479-4514, XTE J1739-302, and IGR J17544-2619 (since October 2007). Out-of-outburst intensity-based X-ray (0.3-10keV) spectroscopy yields absorbed power laws with by…

Very Faint X-ray Transients (VFXTs) are a class of X-ray binary systems that exhibit occasional outbursts with peak X-ray luminosities (L_X< 1e36 erg s^-1) much lower than typical X-ray transients. On 22nd February 2024, during its daily…

We have discovered with the Wide Field Cameras on board BeppoSAX the weak transient X-ray source SAXJ2239.3+6116 whose position coincides with that of 4U2238+60/3A2237+608 and is close to that of the fast transient AT2238+60 and the…

Swift J1626.6-5156 is a Be/X-ray binary that was in outburst from December 2005 until November 2008. We have examined RXTE/PCA and HEXTE spectra of three long observations of this source taken early in its outburst, when the PCA 2-20 keV…

IGR J18179-1621 is a hard X-ray binary transient discovered recently by INTEGRAL. Here we report on detailed timing and spectral analysis on IGR J18179-1621 in X-rays based on available INTEGRAL and Swift data. From the INTEGRAL analysis,…

Details of the discovery of a new X-ray source, IGR J18462-0223, on October 12, 2007, during a short (several hours), intense (~ 35 mCrab at the peak) outburst of hard radiation by the IBIS/ISGRI gamma-ray telescope onboard the INTEGRAL…

We present the results from INTEGRAL and Swift/XRT observations of the hitherto poorly studied unidentified X-ray transient AX J1949.8+2534, and on archival multiwavelength observations of field objects. Bright hard X-ray outbursts have…

IGR J17544-2619 and XTE J1739-302 are considered the prototypical sources of the new class of High Mass X-ray Binaries, the Supergiant Fast X-ray Transients (SFXTs).These sources were observed during bright outbursts on 2008 March 31 and…

SAX J0635.2+0533 is a binary pulsar with a very short pulsation period ($P$ = 33.8 ms) and a high long-term spin down ($\dot P$ $>$ 3.8$\times10^{-13}$ s s$^{-1}$), which suggests a rotation-powered (instead of an accretion-powered) nature…