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1.
INTEGRAL, the International Gamma-Ray Astrophysics Laboratory, to be launched in 2001, is the second medium-size scientific mission (M2) of the ESA long term programme Horizon 2000. INTEGRAL addresses the fine spectroscopy and accurate positioning of celestial gamma-ray sources in the energy range 10 keV to 10 MeV. The observational requirements will be met by a payload utilising coded mask imaging in combination with detector pixel arrays (Imaging) and cooled Germanium detectors (Spectroscopy). INTEGRAL is an ESA led mission in collaboration with Russia and USA. Most of the observing time will be made available to the general scientific community.This paper is largely based on the INTEGRAL Phase A study report (ESA SCI(93)1), written by the INTEGRAL Phase A Science Working Team: S. Bergeson-Willis, T.J.-L. Courvoisier, A.J. Dean, Ph. Durouchoux, B. McBreen, N. Eismont, N. Gehrels, J.E. Grindlay, W.A. Mahoney, J.L. Matteson, O. Pace, T.A. Prince, V. Schönfelder, G.K. Skinner, R. Sunyaev, B.N. Swanenburg, B.J. Teegarden, P. Ubertini, G. Vedrenne, G.E. Villa, S. Volonté, and C. Winkler.  相似文献   

2.
INTEGRAL is operational since more than three years and producing high quality data that allows to detect fainter new hard X-ray sources. The new sources, identified until now, are mostly active galactic nuclei and absorbed or transient high mass X-ray binaries. TeV emission could be expected from the new high mass X-ray binaries accreting dense clumps of stellar wind. INTEGRAL sources with TeV counterparts are discussed. Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA.  相似文献   

3.
The European Space Agency γ-ray telescope, INTEGRAL , is detecting relatively more intrinsically rare cataclysmic variables (CVs) than were found by surveys at lower energies. Specifically, a large fraction of the CVs that are INTEGRAL sources consists of asynchronous polars and intermediate polars (IPs). IP classifications have been proposed for the majority of CVs discovered by INTEGRAL , but, in many cases, there is very little known about these systems. In order to address this, I present time-resolved optical data of five CVs discovered through INTEGRAL observations. The white dwarf spin modulation is detected in high-speed photometry of three of the new CVs (IGR J15094−6649, IGR J16500−3307 and IGR J17195−4100), but two others (XSS J12270−4859 and IGR J16167−4957) show no evidence of magnetism, and should be considered unclassified systems. Spectroscopic orbital period ( P orb) measurements are also given for IGR J15094−6649, IGR J16167−4957, IGR J16500−3307 and IGR J17195−4100.  相似文献   

4.
《New Astronomy Reviews》2002,46(8-10):597-604
The ESA-Mission INTEGRAL (International Gamma-Ray Astrophysics Laboratory) is the next step in low-energy gamma-ray astronomy (up to 10 MeV) and will be launched in 2002. The spectrometer SPI—one of its two main instruments—is dedicated to high-resolution line spectroscopy (ΔE=2.5 keV FWHM at 1.3 MeV). SPI will concentrate on the study of lines from radioactive isotopes. A wealth of new information is expected from interstellar line emission with narrow line profiles, but exciting results are also expected from line profile measurements of individual line emitting objects such as supernovae, supernova remnants, and novae.  相似文献   

5.
In spite of the recent successes of SIGMA, RXTE andCompton GRO, and the launch of INTEGRAL in 2001, a lot ofquestions will stay opened for the next decades in gamma-ray astronomy.In this context we have to think about future instrument concepts whichwill allow a new step in the understanding of high-energy phenomena atwork in many exciting objects: binary systems with compact objects,active galactic nuclei, supernovae and novae, gamma ray bursters...A short overview of these new types of instruments will be given.  相似文献   

6.
For the first time a quasi-simultaneous multi-wavelength campaign has been performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band. 4U 0142+61 was an INTEGRAL target for 1 Ms in July 2005. During these observations it was also observed in the X-ray band with Swift and RXTE, in the optical and NIR with Gemini North and in the radio with the WSRT. In this paper we present the source-energy distribution. The spectral results obtained in the individual wave bands do not connect smoothly; apparently components of different origin contribute to the total spectrum. Remarkable is that the INTEGRAL hard X-ray spectrum (power-law index 0.79±0.10) is now measured up to an energy of ～230 keV with no indication of a spectral break. Extrapolation of the INTEGRAL power-law spectrum to lower energies passes orders of magnitude underneath the NIR and optical fluxes, as well as the low ～30 μJy (2σ) upper limit in the radio band.  相似文献   

7.
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   

8.
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   

9.
《New Astronomy Reviews》2002,46(8-10):605-609
The SPI, Spectrometer aboard the ESA INTEGRAL satellite, to be launched in 2002, will study the gamma ray sky in the 20 keV to 8 MeV energy band with a spectral resolution of 2 keV for photons of 1 MeV thanks to its 19 germanium detectors. A coded mask imaging technique provides for a 2° angular resolution. An active BGO veto shield is used for background rejection. After the integration and test campaigns at CNES in Toulouse, the flight model of SPI has recently undergone a 1 month pre-launch calibration campaign at the CEA center of Bruyères le Châtel, using an accelerator for homogeneity measurements and high activity radioactive sources for imaging performance measurements. We report on the operational aspects of those measurements, whose analysis is foreseen to be published before launch.  相似文献   

10.
Models of Galactic 1.275‐MeV emission produced by the decay of the radionuclide 22Na have been computed. Several frequency–spatial distributions of novae have been investigated using recent results of nova rates and spatial distributions of novae in our Galaxy. These models allow us to estimate the lower limit of the 22Na mass ejected per ONe nova detectable with the future spectrometer (SPI) of the INTEGRAL observatory as a function of the frequency–spatial distribution of ONe novae in the Galaxy. Calculations using recent estimations of the expected 22Na mass ejected per ONe nova show that the detection of the Galactic emission of 1.275‐MeV photons will be difficult with the future spectrometer of the INTEGRAL observatory, whereas the cumulative emission around the Galactic Centre has some chance of being detected during the deep survey of the central radian of the Galaxy.  相似文献   

11.
《New Astronomy Reviews》2002,46(8-10):625-629
High resolution γ-ray spectroscopy at energies around 1 MeV, as with SPI on board INTEGRAL, is a powerful tool for astronomy with radioactivities. We do not expect the SPI signal-to-background ratio for any of the anticipated γ-ray sources to exceed a few percent; hence detailed modelling of the instrumental background will be crucial. We exploit the similarities between TGRS on board WIND and SPI with respect to orbit and radiation environment, as well as detector design and material composition, to anticipate the most important instrumental background lines and their production channels in SPI at the energies of selected γ-ray lines of astrophysical relevance.  相似文献   

12.
Thanks to INTEGRAL’s long exposures of the Galactic Plane, the two brightest Soft Gamma-Ray Repeaters, SGR 1806-20 and SGR 1900+14, have been monitored and studied in detail for the first time at hard-X/soft gamma rays. This has produced a wealth of new scientific results, which we will review here. Since SGR 1806-20 was particularly active during the last two years, more than 300 short bursts have been observed with INTEGRAL and their characteristics have been studied with unprecedented sensitivity in the 15–200 keV range. A hardness-intensity anticorrelation within the bursts has been discovered and the overall Number-Intensity distribution of the bursts has been determined. In addition, a particularly active state, during which 100 bursts were emitted in 10 minutes, has been observed on October 5 2004, indicating that the source activity was rapidly increasing. This eventually led to the Giant Flare of December 27th 2004, for which a possible soft gamma-ray (>80 keV) early afterglow has been detected. The deep observations allowed us to discover the persistent emission in hard X-rays (20–150 keV) from 1806-20 and 1900+14, the latter being in a quiescent state, and to directly compare the spectral characteristics of all Magnetars (two SGRs and three Anomalous X-ray Pulsars) detected with INTEGRAL. D.G. acknowledges the French Space Agency (CNES) for financial support. Based on observations with INTEGRAL, an ESA project with instruments and the science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA. ISGRI has been realized and maintained in flight by CEA-Saclay/DAPNIA with the support of CNES. K.H. is grateful for support under NASA’s INTEGRAL U.S. Guest Investigator program, Grants NAG5-13738 and NNG05GG35G.  相似文献   

13.
We analyze uncertainties in the cosmic X-ray background measurements performed by the INTEGRAL observatory. We find that the most important effect limiting the accuracy of the measurements is related to the intrinsic background variation in detectors. Taking into account all of the uncertainties arising during the measurements we conclude that the X-ray background intensity obtained in the INTEGRAL observations is compatible with the historic X-ray background observations performed by the HEAO-1 satellite.  相似文献   

14.
We outline the basic idea of an automatically working telescope based on inexpensive commercially available hardware components. A new generation of the control software is proposed which makes the full remote control of the telescope via Internet network possible - without human factor. The main scientific goal is to provide quasisimultaneous optical data for gamma-ray satellite projects such as CGRO, HETE, INTEGRAL etc. The telescope will automatically investigate the positions of high energy sources such as GRB and AGNs, at optical wavelengths. The automatically operated burst alert telescope is expected to improve our knowledge of these astrophysical objects. The proposed experiment is different from the OTM Optical Transient Monitor which is monitoring experiment unrelated to satellite data. The system can be also applied in other areas of astronomy and astrophysics as well as provide sky patrol.  相似文献   

15.
The recent completion and operation of the High Energy Stereoscopic System [1], an array of ground based imaging Cherenkov telescopes, has provided a survey with unprecedented sensitivity of the inner part of the Galaxy and revealed a new population of very high energy gamma-rays sources emitting at E > 100 GeV. Most of them were reported to have no known radio or X-ray counterpart and hypothesised to be representative of a new class of dark nucleonic cosmic sources. In fact, very high energy gamma-rays with energies E > 1011 eV are the best proof of non-thermal processes in the universe and provide a direct in-site view of matter-radiation interaction at energies by far greater than producible in ground accelerators. At lower energy INTEGRAL has regularly observed the entire galactic plane during the first 1000 day in orbit providing a survey in the 20–100 keV range resulted in a soft gamma-ray sky populated with more than 200 sources, most of them being galactic binaries, either Black Hole Candidates (BHC) or Neutron Stars (NS) [5]. Very recently, the INTEGRAL new source IGR J18135-1751 has been identified as the soft gamma-ray counterpart of HESS J1813-178 [18] and AXJ1838.0-0655 as the X/gamma-ray counterpart of HESS J1837-069 [14].Detection of non-thermal radio, X and gamma-ray emission from these TeV sources is very important to discriminate between various emitting scenarios and, in turn, to fully understand their nature.The implications of these new findings in the high energy Galactic population will be addressed.On behalf of the IBIS Survey Team  相似文献   

16.
The possibility of investigating the sky region near the Galactic center with instruments of the INTEGRAL orbital astrophysical gamma-ray observatory by the method of its occultation by the Earth and the Moon is considered. Existing engineering constraints on the observing conditions, such as the admissible orientation of the INTEGRAL satellite relative to the direction to the Sun and the performance of measurements only outside the Earth??s radiation belts, are taken into account. Long time intervals during which the lunar occultation center passes at angular distances of less than 2° from the Galactic center have been found. Such events occur under the adopted constraints two or three times per year without any correction of the INTEGRAL satellite orbit. The orbit can be corrected to reduce the angular distance between the Moon and the Galactic center in occultation events. The required velocity impulses do not exceed several meters per second. The possibility of the Galactic center being occulted by the Earth has been analyzed. In this case, to perform measurements, the admissible (in radiation exposure) height of the working segment of the orbit should be reduced to 25 000 km, which can be problematic. At the same time, part of the Galaxy??s equatorial region is shadowed by the Earth for a time long enough to carry out the corresponding experiments.  相似文献   

17.
We present the results of our analysis of the JEM-X/INTEGRAL data obtained from January 2003 to January 2015 aimed at searching for type I X-ray bursts from known and new bursters. Such bursts are caused by thermonuclear explosions on the surface of a neutron star. We have searched for bursts in the records of the count rate of the JEM-X detectors in the 3–20 keV energy band. We have separately reconstructed and analyzed the light curves of 104 X-ray bursters known to date based on the JEM-X data. A similar search for bursts was previously carried out in the 15–25 keV data from the IBIS/ISGRI telescope onboard the INTEGRAL observatory obtained in 2003–2009. We have continued to analyze the data from this telescope up until the observations in January 2015. The joint catalog of bursts detected by the two instruments includes 2201 events; their basic parameters are given. The large size of the sample of bursts makes it one of the most representative of the existing one and allows various statistical studies of bursts to be performed. In particular, we have constructed the dependence of the mean rate of type I bursts from bursters on the luminosity (accretion rate), revealed an appreciable burst rate from sources with a near-Eddington luminosity, and investigated the population of multiple bursts with a recurrence time much shorter than the time it takes for a critical mass of matter required for the initiation of an explosion to be accumulated on the neutron star surface. Almost all of the detected bursts are associated with already known bursters,we have found only one previously unknown burster, IGRJ17380-3749, in the archival data, and one more known, but poorly studied source, AX J1754.2-2754, has been identified as a burster. Several similar sources have previously been identified as bursters directly during the INTEGRAL observations.  相似文献   

18.
We develop a Monte Carlo technique based on L.B. Lucy's indivisible photon packets method to calculate X-ray continuum spectra of Comptonized thermal plasma in arbitrary geometry and apply it to describe the broad-band X-ray continuum of the galactic superaccreting microquasar SS433 observed by INTEGRAL . A physical model of the X-ray emitting region is proposed that includes thermal emission from the accretion disc, jets and hot corona where the photons of different origin are Comptonized. From comparison with INTEGRAL observations, we estimate physical parameters of the complex X-ray emitting region in SS433 and present model spectra for different viewing angles of the object.  相似文献   

19.
We present the results of our optical identification of the X-ray source IGR J16547-1916 detected by the INTEGRAL observatory during a deep all-sky survey. Analysis of the spectroscopic data from the SWIFT and INTEGRAL observatories in the X-ray energy band and from the BTA (Special Astrophysical Observatory) telescope in the optical band has shown that the source is most likely an intermediate polar—an accreting white dwarf with the mass ofM WD μ 0.85M ⊙ binary system. Subsequent studies of the object’s rapid variability with the RTT-150 telescope have confirmed this conclusion by revealing periodic pulsations of its optical emission with a period of ≈550 s.  相似文献   

20.
P. Zasche 《New Astronomy》2010,15(1):150-154
Thirty-three eclipsing binaries were selected for an analysis from a huge database of observations made by the INTEGRAL/OMC camera. The photometric data were processed and analyzed, resulting in a first light-curve study of these neglected eclipsing binaries. The system CY Lac was discovered to be an eccentric one. In several systems from this sample even their orbital periods have been confirmed or modified. Due to missing spectroscopic study of these stars, further detailed analyses are still needed.  相似文献   

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