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1.
We analyze in detail the ASCA observations of the hard X-ray source IGR J16318-4848, which was recently discovered by the INTEGRAL observatory (Courvoisier et al. 2003). The source has an anomalously hard spectrum in the energy range 0.5–10 keV and is virtually undetectable below 4 keV because of strong photoabsorption (n H L>4×1023 cm?2). The Kα line of neutral or weakly ionized iron with an equivalent width of ～2.5 keV dominates in the energy range 4–10 keV. There is also evidence for the presence of a second line at energy ～7 keV. Our analysis of archival observational data for the infrared counterpart of IGR J16318-4848 that was discovered by Foschini et al. (2003) revealed the source in the wavelength range 1–15 µm. Available data suggest that the object can be an X-ray binary system surrounded by a dense envelope. The source may be a high-mass X-ray binary similar to GX 301-2. We believe that IGR J16318-4848 can be the first representative of a hitherto unknown population of strongly absorbed Galactic X-ray sources that could not be detected by previous X-ray observatories. 相似文献
2.
The X-ray source IGR J16318-4848 was the first source discovered by INTEGRAL on January 29, 2003. The high energy spectrum
exhibits such a high column density that the source is undetectable in X-rays below 2 keV. On February 23–25, 2003 we triggered
a Target of Opportunity (ToO) Program using the EMMI and SOFI instruments on the New Technology Telescope of the European
Southern Observatory (La Silla) to get optical and near-infrared (NIR) observations. We discovered the optical counterpart,
and confirmed the already proposed candidate in the NIR. NIR spectroscopy revealed a large amount of emission lines, including
forbidden iron lines and P-Cygni profiles, showing a strong similarity with CI Cam, another strongly absorbed source. Together
with the spectral energy distribution (SED), these data point to a high luminosity, high temperature source, with an intrinsic
absorption greater than the interstellar absorption, but two orders of magnitude below the X-ray absorption. All these observations
show that IGR J16318-4848 is a high mass X-ray binary (HMXB) at a distance between 0.9 and 6.2 kpc, the mass donor being an
early-type star, probably a sgB[e] star, surrounded by a dense and absorbing circumstellar material. This would make the second
HMXB with a sgB[e] star as the mass donor after CI Cam.
Other sources, discovered by INTEGRAL near IGR J16318-4848 in the direction of the Norma arm, present the same characteristics,
at least in X-rays. Such sources may represent a different evolutionary state of X-ray binaries previously undetected with
the lower energy space telescopes; if it is so, a new class of strongly absorbed X-ray binaries is being unveiled by INTEGRAL.
Out of the 15 sources present in this region, only one might be associated with an unidentified EGRET source: IGR J16393-4643.
Therefore these obscured INTEGRAL sources do not seem to be powerful high energy (E > 100 MeV) emitters.
Based on observations collected at the European Southern Observatory, Chile (proposal ESO N∘ 70.D-0340). 相似文献
3.
E. V. Filippova S. S. Tsygankov A. A. Lutovinov R. A. Sunyaev 《Astronomy Letters》2005,31(11):729-747
We present spectra for 34 accretion-powers X-ray pulsars and one millisecond pulsar that were within the field of view of the INTEGRAL observatory over two years (December 2002–January 2005) of its in-orbit operation and that were detected by its instruments at a statistically significant level (> 8σ in the energy range 18–60 keV). There are seven recently discovered objects of this class among the pulsars studied: 2RXP J130159.6-635806, IGR/AX J16320-4751, IGR J16358-4726, AX J163904-4642, IGR J16465-4507, SAX/IGR J18027-2017, and AX J1841.0-0535. We have also obtained hard X-ray (>20 keV) spectra for the accretion-powered pulsars RX J0146.9+6121, AX J1820.5-1434, and AX J1841.0-0535 for the first time. We analyze the evolution of spectral parameters as a function of the intensity of the sources and compare these with the results of previous studies. 相似文献
4.
We present the results of our analysis of the RXTE observations for two transient sources, IGR J17091-3624 and IGR J18539+0727, in April 2003. The derived energy spectra of the sources and the power-density spectra of their light curves make it possible to classify them as low/hard-state X-ray binaries. The parameters of the power spectrum for IGR J18539+0727 lead us to tentatively conclude that the compact object in this binary is a black hole. 相似文献
5.
R. A. Burenin I. F. Bikmaev M. G. evnivtsev J. A. Tomsick S. Yu. Sazonov M. N. Pavlinsky R. A. Sunyaev 《Astronomy Letters》2009,35(2):71-74
We present the results of our optical identification of the hard X-ray source IGR J18257-0707 through its spectrophotometric observations with the optical RTT-150 telescope. The accurate position of the X-ray source determined using Chandra observations has allowed this source to be confidently associatedwith a faint optical object (m R ≈ 20.4) whose optical spectrumexhibits a broad H α emission line at redshift z = 0.037. Thus, the source IGR J18257-0707 is a type-1 Seyfert galaxy at redshift z = 0.037. 相似文献
6.
D. C. Hannikainen M. G. Rawlings P. Muhli O. Vilhu J. Schultz J. Rodriguez 《Monthly notices of the Royal Astronomical Society》2007,380(2):665-668
The International Gamma-Ray Astrophysics Laboratory observatory has been (re-)discovering new X-ray sources since the beginning of nominal operations in early 2003. These sources include X-ray binaries, active galactic nuclei, cataclysmic variables, etc. Amongst the X-ray binaries, the true nature of many of these sources has remained largely elusive, though they seem to make up a population of highly absorbed high-mass X-ray binaries. One of these new sources, IGR J19140+0951, was serendipitously discovered on 2003 March 6 during an observation of the galactic microquasar GRS 1915+105. We observed IGR J19140+0951 with the United Kingdom Infrared Telescope in order to identify the infrared counterpart. Here we present the H - and K -band spectra. We determined that the companion is a B0.5-type bright supergiant in a wind-fed system, at a distance ≲5 kpc. 相似文献
7.
Details of the discovery (in February 2004) and results of subsequent (in 2004–2009) INTEGRAL observations of the transient
X-ray burster IGR J17380-3749 (IGR J17379-3747) are presented. Over the period of its observations, the INTEGRAL observatory
recorded two hard X-ray flares and one type I X-ray burst from the source, which allowed the nature of IGR J17380-3749 to
be determined. The burster radiation spectrum during the flares was hard—a power law with a photon index α = 1.8–2.0 or bremsstrahlung corresponding to a plasma with a temperature kT = 90–140 keV. The spectral shape at the flare peaks turned out to be the same, despite a more than twofold difference in
flux (the peak flux recorded in the energy range 18–100 keV reached ∼20 mCrab). The upper limit on the flux from the source
in its quiescent (off) state in the range of 18–40 keV was 0.15 mCrab (3σ). 相似文献
8.
H. Sreehari Anuj Nandi D. Radhika Nirmal Iyer Samir Mandal 《Journal of Astrophysics and Astronomy》2018,39(1):5
We report on our attempt to understand the outbursting profile of Galactic Black Hole sources, keeping in mind the evolution of temporal and spectral features during the outburst. We present results of evolution of quasi-periodic oscillations, spectral states and possible connection with jet ejections during the outburst phase. Further, we attempt to connect the observed X-ray variabilities (i.e., ‘class’/‘structured’ variabilities, similar to GRS 1915+105) with spectral states of black hole sources. Towards these studies, we consider three black hole sources that have undergone single (XTE J1859+226), a few (IGR J17091-3624) and many (GX 339-4) outbursts since the start of RXTE era. Finally, we model the broadband energy spectra (3–150 keV) of different spectral states using RXTE and NuSTAR observations. Results are discussed in the context of two-component advective flow model, while constraining the mass of the three black hole sources. 相似文献
9.
We report on the 2016 outburst of the transient Galactic Black Hole candidate IGR J17091-3624 based on the observation campaign carried out with SWIFT and NuSTAR. The outburst profile, as observed with SWIFT-XRT, shows a typical ‘q’-shape in the Hardness Intensity Diagram (HID). Based on the spectral and temporal evolution of the different parameters, we are able to identify all the spectral states in the q-profile of HID and the Hardness-RMS diagram (HRD). Both XRT and NuSTAR observations show an evolution of low frequency Quasi periodic oscillations (QPOs) during the low hard and hard intermediate states of the outburst rising phase. We also find mHz QPOs along-with distinct coherent class variabilities (heartbeat oscillations) with different timescales, similar to the \(\rho \)-class (observed in GRS 1915+105). Phenomenological modelling of the broad-band XRT and NuSTAR spectra also reveals the evolution of high energy cut-off and presence of reflection from ionized material during the rising phase of the outburst. Further, we conduct the modelling of X-ray spectra of SWIFT and NuSTAR in 0.5–79 keV to understand the accretion flow dynamics based on two component flow model. From this modelling, we constrain the mass of the source to be in the range of \(10.62\mbox{--}12.33~\mbox{M}_{\odot }\) with 90% confidence, which is consistent with earlier findings. 相似文献
10.
I. F. Bikmaev E. A. Nikolaeva V. V. Shimansky A. I. Galeev R. Ya. Zhuchkov E. N. Irtuganov S. S. Melnikov N. A. Sakhibullin S. A. Grebenev L. M. Sharipova 《Astronomy Letters》2017,43(10):664-676
We present the results of our long-term photometric and spectroscopic observations at the Russian–Turkish RTT-150 telescope for the optical counterpart to one of the best-known sources, representatives of the class of fast X-ray transients, IGR J17544-2619. Based on our optical data, we have determined for the first time the orbital and physical parameters of the binary system by the methods of Doppler spectroscopy.We have calculated theoretical spectra of the optical counterpart by applying non- LTE corrections for selected lines and obtained the parameters of the stellar atmosphere (T eff = 33 000 K, log g = 3.85, R = 9.5 R ⊙, and M = 23 M ⊙). The latter suggest that the optical star is not a supergiant as has been thought previously. 相似文献
11.
R. A. Burenin A. V. Mescheryakov M. G. Revnivtsev S. Yu. Sazonov I. F. Bikmaev M. N. Pavlinsky R. A. Sunyaev 《Astronomy Letters》2008,34(6):367-374
We present the results of our optical identifications of a set of X-ray sources from the INTEGRAL and SWIFT all-sky surveys. The optical data have been obtained with the 1.5-m Russian-Turkish Telescope (RTT-150). Nine X-ray sources have been identified with active galactic nuclei (AGNs). Two of them are located in the nearby spiral galaxies MCG-01-05-047 and NGC 973 seen almost edge-on. One source, IGR J16562-3301, is probably a BL Lac object (blazar). The remaining AGNs are observed as the starlike nuclei of spiral galaxies whose spectra exhibit broad emission lines. The relation between the hard X-ray (17–60 keV) luminosity and the [O III] 5007 line luminosity, log L x/L [O III] ≈ 2.1, holds good for most of the AGNs detected in hard X rays. However, the luminosities of some AGNs deviate from this relation. The fraction of such objects can reach ～20%. In particular, the [O III] line flux is lower for two nearby edge-on spiral galaxies. This can be explained by the effect of absorption in the galactic disks. 相似文献
12.
L. Sidoli P. Romano L. Ducci A. Paizis G. Cusumano V. Mangano H. A. Krimm S. Vercellone D. N. Burrows J. A. Kennea N. Gehrels 《Monthly notices of the Royal Astronomical Society》2009,397(3):1528-1538
We report on new X-ray outbursts observed with Swift from three Supergiant Fast X-ray Transients (SFXTs): XTE J1739−302, IGR J17544−2619 and IGR J08408−4503. XTE J1739−302 underwent a new outburst on 2008 August 13, IGR J17544−2619 on 2008 September 4 and IGR J08408−4503 on 2008 September 21. While the XTE J1739−302 and IGR J08408−4503 bright emission triggered the Swift /Burst Alert Telescope, IGR J17544−2619 did not, thus we could perform a spectral investigation only of the spectrum below 10 keV. The broad-band spectra from XTE J1739−302 and IGR J08408−4503 were compatible with the X-ray spectral shape displayed during the previous flares. A variable absorbing column density during the flare was observed in XTE J1739−302 for the first time. The broad-band spectrum of IGR J08408−4503 requires the presence of two distinct photon populations, a cold one (∼0.3 keV) most likely from a thermal halo around the neutron star and a hotter one (1.4–1.8 keV) from the accreting column. The outburst from XTE J1739−302 could be monitored with a very good sampling, thus revealing a shape which can be explained with a second wind component in this SFXT, in analogy to what we have suggested in the periodic SFXT IGR J11215−5952. The outburst recurrence time-scale in IGR J17544−2619 during our monitoring campaign with Swift suggests a long orbital period of ∼150 d (in a highly eccentric orbit), compatible with what previously observed with INTEGRAL . 相似文献
13.
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 observatory
are given. The detection of another earlier outburst from this source occurred on April 28, 2006, in the archival data of
the telescope is reported. We present the results of the source’s localization and our spectral/timing analysis of the observational
data. The source may turn out to be yet another representative of the continuously growing population of fast X-ray transients,
which are the focus of attention because of the identification of their optical counterparts with early-type supergiants. 相似文献
14.
L. Prat J. Rodriguez D. C. Hannikainen S. E. Shaw 《Monthly notices of the Royal Astronomical Society》2008,389(1):301-310
We have used the RXTE and INTEGRAL satellites simultaneously to observe the high-mass X-ray binary (HMXB) IGR J19140+0951. The spectra obtained in the 3–80 keV range have allowed us to perform a precise spectral analysis of the system along its binary orbit. The spectral evolution confirms the supergiant nature of the companion star and the neutron star nature of the compact object. Using a simple stellar wind model to describe the evolution of the photoelectric absorption, we were able to restrict the orbital inclination angle in the range 38°–75°. This analysis leads to a wind mass-loss rate from the companion star of ∼5 × 10−8 M⊙ yr−1 , consistent with an OB I spectral type. We have detected a soft excess in at least four observations, for the first time for this source. Such soft excesses have been reported in several HMXBs in the past. We discuss the possible origin of this excess, and suggest, based on its spectral properties and occurrences around the superior conjunction, that it may be explained as the reprocessing of the X-ray emission originating from the neutron star by the surrounding ionized gas. 相似文献
15.
A. A. Lutovinov A. I. Mironov R. A. Burenin M. G. Revnivtsev S. S. Tsygankov M. N. Pavlinsky I. V. Korobtsev M. V. Eselevich 《Astronomy Letters》2013,39(8):513-522
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 observatories as well as observations with the RTT-150 and AZT-33IK optical telescopes. Two sources (SWIFT J1553.6+2606 and SWIFT J1852.2+8424) are shown to be extragalactic in nature: the first is a quasar, while the recordedX-ray flux from the second is the total emission from two Seyfert 1 galaxies at redshifts 0.1828 and 0.2249. The source IGR J22534+6243 resides in our Galaxy and is an X-ray pulsar with a period of ～46.674 s that is a member of a high-mass X-ray binary with a Be star. The nature of yet another Galactic source, SWIFT J1852.8+3002, is not completely clear and infrared spectroscopy is needed to establish it. 相似文献
16.
I. F. Bikmaev R. A. Burenin M. G. Revnivtsev S. Yu. Sazonov R. A. Sunyaev M. N. Pavlinsky N. A. Sakhibullin 《Astronomy Letters》2008,34(10):653-663
The results of optical identifications of five hard X-ray sources in the Galactic plane from the INTEGRAL all-sky survey are presented. The X-ray data on one source (IGR J20216+4359) are published for the first time. The optical observations were performed with the 1.5-m RTT-150 telescope (Turkish National Observatory, Antalya, Turkey) and the 6-m BTA telescope (Special Astrophysical Observatory, Nizhny Arkhyz, Russia). A blazar, three Seyfert galaxies, and a high-mass X-ray binary are among the identified sources. 相似文献
17.
D. I. Karasev A. A. Lutovinov M. G. Revnivtsev R. A. Krivonos 《Astronomy Letters》2012,38(10):629-637
We present the results of Chandra and XMM-Newton observations for six hard X-ray sources (IGR J12134-6015, IGR J18293-1213, IGR J18219-1347, IGR J17350-2045, IGR J18048-1455, XTE J1901+014) from the INTEGRAL all-sky survey. Based on these observations, we have improved significantly the localization accuracy of the objects and, therefore, have managed to identify their optical counterparts. Using data from the publicly available 2MASS and UKIDSS infrared sky surveys as well as data from the SOFI/NTT telescope (European Southern Observatory), we have determined the magnitudes of the optical counterparts, estimated their types and (in some cases) the distances to the program objects. A triplet of iron lines with energies of 6.4, 6.7, and 6.9 keV has been detected in the X-ray spectrum of IGR J18048-1455; together with the detection of pulsations with a period of ～1440 s from this source, this has allowed it to be classified as a cataclysmic variable, most likely an intermediate polar. In addition, broadband X-ray spectra of IGR J12134-6015 and IGR J17350-2045 in combination with infrared and radio observations suggest an extragalactic nature of these objects. The source IGR J18219-1347 presumably belongs to the class of high-mass X-ray binaries. 相似文献
18.
M. G. Revnivtsev S. Yu. Sazonov S. V. Molkov A. A. Lutovinov E. M. Churazov R. A. Sunyaev 《Astronomy Letters》2006,32(3):145-148
This paper belongs to a series of papers devoted to a hard X-ray survey of the sky. We analyze a large set of observations of the Galactic plane region in Crux with the IBIS telescope onboard the INTEGRAL observatory. We have detected 47 sources. There are 12 active galactic nuclei and 11 and 6 galactic binary systems with high-mass and low-mass optical companions, respectively, among the identified objects. Thirteen objects remain unidentified. 相似文献
19.
D. I. Karasev A. A. Lutovinov A. Yu. Tkachenko G. A. Khorunzhev R. A. Krivonos P. S. Medvedev M. N. Pavlinsky R. A. Burenin M. V. Eselevich 《Astronomy Letters》2018,44(8-9):522-540
We present the results of our optical identifications of several hard X-ray sources from the INTEGRAL all-sky survey obtained over 14 years of observations. Having improved the positions of these objects in the sky with the X-ray telescope (XRT) of the Swift observatory and the XMMNewton observatory, we have identified their counterparts using optical and infrared sky survey data. We have obtained optical spectra for more than half of the objects from our sample with the RTT-150 and AZT-33IK telescopes, which have allowed us to establish the nature of the objects and to measure their redshifts. Six sources are shown to be extragalactic in origin and to belong to Seyfert 1 and 2 galaxies (IGR J01017+6519, IGR J08215-1320, IGR J08321-1808, IGR J16494-1740, IGR J17098-2344, IGR J17422-2108); we have failed to draw definitive conclusions about the nature of four more objects (IGR J11299-6557, IGR J14417-5533, IGR J18141-1823, IGR J18544+0839), but, judging by circumstantial evidence, they are most likely also extragalactic objects. For one more object (IGR J18044-1829) no unequivocal identification has been made. 相似文献
20.
During the GRIF experiment onboard the Mir orbiting station, the sky was monitored with a PX-2 wide-field (～1 sr) scintillation X-ray spectrometer to detect bursts in the photon energy range 10–300 keV. Because of the comprehensive instrumentation, which, apart from the X-ray and gamma-ray instruments, also included charged-particle detectors, the imitations of astrophysical bursts by magnetospheric electron precipitations and strongly ionizing nuclei were effectively filtered out. It was also possible to separate solar and atmospheric events. Several tens of bursts interpreted as being astrophysical were detected in the experiment at sensitivity levels S～10?7 erg cm?2 (for bursts whose spectra were characterized by effective temperatures kT～100 keV) and S～3×10?8 erg cm?2 (for bursts with kT～25 keV). Some of the soft gamma-ray or hard X-ray bursts with kT～10–50 keV were identified with the bursting pulsar GRO J1744-28. Our estimate of the detection rate for cosmological soft gamma-ray or hard X-ray bursts from the entire sky suggests that the distributions of long-duration (>1 s) gamma-ray bursts (GRBs) in characteristic energy kT and duration are inconsistent with the steady-state cosmological model in which the evolution of burst sources is disregarded. Based on GRIF and BATSE/CGRO data, we conclude that most of the GRB sources originate at redshifts 1<z<5. 相似文献