scholarly journals Spectroscopic identification of INTEGRAL high-energy sources with VLT/ISAAC

2018 ◽  
Vol 618 ◽  
pp. A150 ◽  
Author(s):  
F. Fortin ◽  
S. Chaty ◽  
A. Coleiro ◽  
J. A. Tomsick ◽  
C. H. R. Nitschelm
Keyword(s):  
Near Infrared ◽  
Cataclysmic Variables ◽  
High Energy ◽  
High Mass ◽  
Energy Sources ◽  
Photometric Variability ◽  
Stellar Spectra ◽  
X Ray ◽  
Very Large Telescope ◽  
X Ray Binaries

Context. The INTEGRAL satellite has been observing the γ-ray sky for 15 years and has detected over 900 X-ray sources of various nature. However, more than 200 of these sources still lack precise identification. Aims. Our goal is to reveal the nature of the high-energy sources detected by INTEGRAL. In particular, we want to improve the census of X-ray binaries. Methods. Photometry and spectroscopy were performed in July 2012 on 14 INTEGRAL sources in near-infrared at the Very Large Telescope on the European Southern Observatory-UT3 telescope equipped with the ISAAC spectrograph. We used Ks images reaching to a depth of magnitude 18.5 to look for unique counterparts to high-energy detections to check for both extended sources and photometric variability. The analysis of near-infrared spectral features allows us to constrain the nature of these X-ray sources by comparing them to stellar spectra atlases. Results. We present photometric and/or spectroscopic data for 14 sources (IGR J00465–4005, IGR J10447–6027, IGR J12489–6243, IGR J13020–6359, IGR J13186–6257, IGR J15293–5609, IGR J17200–3116, IGR J17404–3655, IGR J17586–2129, IGR J17597–2201, IGR J18457+0244, IGR J18532+0416, IGR J19308+0530, and IGR J19378–0617). We conclude that 5 of these are active galactic nuclei, 5 are cataclysmic variables, 2 are low- or intermediate-mass X-ray binaries, and 2 are Be high-mass X-ray binaries.

Spectroscopic identication of INTEGRAL high-energy sources with VLT/ISAAC

2018 ◽  
Vol 14 (S346) ◽  
pp. 49-54
Author(s):  
F. Fortin ◽  
S. Chaty ◽  
A. Coleiro ◽  
J. A. Tomsick ◽  
C. H. R. Nitschelm
Keyword(s):  
Near Infrared ◽  
Cataclysmic Variables ◽  
High Energy ◽  
High Mass ◽  
Energy Sources ◽  
Exact Nature ◽  
Stellar Spectra ◽  
Infrared Observations ◽  
X Ray ◽  
X Ray Binaries

AbstractINTEGRAL has been observing the γ-ray sky for 15 years and has discovered many high-energy sources of various nature. Among them, active galactic nuclei (AGN), low or high-mass X-ray binaries (LMXB and HMXB) and cataclysmic variables (CV) are rather difficult to differentiate from one another at high energies and require further optical or near-infrared observations to constrain their exact nature. Using near-infrared photometric and spectroscopic data from ESO VLT/ISAAC, we aim to reveal the nature of 14 high-energy INTEGRAL sources and improve the census of X-ray binaries. By comparing their spectral features to stellar spectra atlases, we identified 5 new CVs, 2 low or intermediate mass X-ray binaries, 2 HMXBs and 5 AGNs.

Commission N°48: High Energy Astrophysics (Astrophysique Des Hautes Energies)

1988 ◽  
Vol 20 (1) ◽  
pp. 671-675
Author(s):  
C.J. Cesarsky ◽  
R.A. Sunyaev ◽  
G.W. Clark ◽  
R. Giacconi ◽  
Vin-Yue Qu ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Supernova Remnants ◽  
Cataclysmic Variables ◽  
Galactic Nuclei ◽  
High Energy ◽  
Clusters Of Galaxies ◽  
High Energy Astrophysics ◽  
X Ray ◽  
X Ray Binaries ◽  
Imaging Telescopes

The european X-ray observatory (EXOSAT), which was launched in 1983 and which finished operations in April 1986, has brought a rich harvest of results in the period 1984-1987, surveyed here. The EXOSAT payload consisted of three sets of instruments: two low energy imaging telescopes (LE:E<2 KeV), a medium-energy experiment (ME:E=l-50KeV) and a gas scintillation proportional counter (GSPC:E=2-20KeV). Over most of the energy range covered, EXOSAT was not more sensitive than its predecessor, the american EINSTEIN satellite. But the EINSTEIN satellite is far from having exhausted the treasures of the X-ray sky. And EXOSAT, thanks to its elliptical 90-hour orbit, had the extra advantage of being able to make long, continuous observations of interesting objects, lasting up to 72 hours. Thus, EXOSAT was very well suited for variability studies, and many of its most important findings are in this area. EXOSAT observations sample a vide range of astrophysical sources: X-ray binaries, cataclysmic variables and active stars; supernova remnants and the interstellar medium; active galactic nuclei, and clusters of galaxies. Among the highlights, let us mention:

scholarly journals Stars at γ-Ray Energies: the INTEGRAL Look at Stars

2004 ◽  
Vol 219 ◽  
pp. 55-62
Author(s):  
Thierry Montmerle
Keyword(s):  
Massive Stars ◽  
High Energy ◽  
Energy Sources ◽  
Late Type ◽  
X Ray ◽  
Γ Ray ◽  
October 17 ◽  
X Ray Binaries ◽  
Observational Program

The European γ-ray satellite INTEGRAL, launched on October 17, 2002, is the successor to the highly successful American satellite Compton-GRO. Even though its main observational program focuses on “classical” high-energy sources like compact X-ray binaries or AGNs, some time is being devoted to γ-ray studies of massive stars and magnetically active late-type stars. We briefly describe here the four instruments of INTEGRAL, and summarize the ongoing stellar programs.

scholarly journals On the origin of Supergiant Fast X-ray Transients

2018 ◽  
Vol 14 (S346) ◽  
pp. 193-196
Author(s):  
Swetlana Hubrig ◽  
Lara Sidoli ◽  
Konstantin A. Postnov ◽  
Markus Schöller ◽  
Alexander F. Kholtygin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Stellar Wind ◽  
Longitudinal Magnetic Field ◽  
High Mass ◽  
Large Telescope ◽  
X Ray ◽  
Very Large Telescope ◽  
Low X ◽  
X Ray Binaries

Abstract. A fraction of high-mass X-ray binaries are supergiant fast X-ray transients. These systems have on average low X-ray luminosities, but display short flares during which their X-ray luminosity rises by a few orders of magnitude. The leading model for the physics governing this X-ray behaviour suggests that the winds of the donor OB supergiants are magnetized. In agreement with this model, the first spectropolarimetric observations of the SFXT IGR J11215-5952 using the FORS 2 instrument at the Very Large Telescope indicate the presence of a kG longitudinal magnetic field. Based on these results, it seems possible that the key difference between supergiant fast X-ray transients and other high-mass X-ray binaries are the properties of the supergiant’s stellar wind and the physics of the wind’s interaction with the neutron star magnetosphere.

scholarly journals Tidal tearing of circumstellar disks in Be/X-ray and gamma-ray binaries

2016 ◽  
Vol 12 (S329) ◽  
pp. 432-432
Author(s):  
Atsuo T. Okazaki
Keyword(s):  
Gamma Ray ◽  
Compact Object ◽  
High Energy ◽  
High Mass ◽  
List Type ◽  
X Ray ◽  
Short Period ◽  
Be Star ◽  
X Ray Binaries

AbstractAbout one half of high-mass X-ray binaries host a Be star [an OB star with a viscous decretion (slowly outflowing) disk]. These Be/X-ray binaries exhibit two types of X-ray outbursts (Stella et al. 1986), normal X-ray outbursts (LX~1036−37 erg s−1) and occasional giant X-ray outbursts (LX > 1037 erg s−1). The origin of giant X-ray outbursts is unknown. On the other hand, a half of gamma-ray binaries have a Be star as the optical counterpart. One of these systems [LS I +61 303 (Porb = 26.5 d)] shows the superorbital (1,667 d) modulation in radio through X-ray bands. No consensus has been obtained for its origin. In this paper, we study a possibility that both phenomena are caused by a long-term, cyclic evolution of a highly misaligned Be disk under the influence of a compact object, by performing 3D hydrodynamic simulations. We find that the Be disk cyclically evolves in mildly eccentric, short-period systems. Each cycle consists of the following stages: 1)As the Be disk grows with time, the initially circular disk becomes eccentric by the Kozai-Lidov mechanism.2)At some point, the disk is tidally torn off near the base and starts precession.3)Due to precession, a gap opens between the disk base and mass ejection region, which allows the formation of a new disk in the stellar equatorial plane (see Figure 1).4)The newly formed disk finally replaces the precessing old disk. Such a cyclic disk evolution has interesting implications for the long-term behavior of high energy emission in Be/X-ray and gamma-ray binaries.

scholarly journals Common-Envelope Evolution, the Formation of CVs, LMXBs, and the Fate of HMXBs

1996 ◽  
Vol 165 ◽  
pp. 3-15 ◽  
Author(s):  
R.E. Taam
Keyword(s):  
Time Scale ◽  
Three Dimensional ◽  
Cataclysmic Variables ◽  
Theoretical Description ◽  
High Mass ◽  
X Ray ◽  
Common Envelope ◽  
The Common ◽  
Binary Evolution ◽  
X Ray Binaries

Recent three-dimensional studies of the common-envelope phase of binary evolution have provided important insights into its theoretical description. The role of non-axisymmetric effects associated with gravitational torques is essential for understanding all aspects of the evolution. For successful ejection of the common envelope and survival of the remnant compact binary it is required that the orbital period of the progenitor system is long, so that one of the components of the system is in the red giant or red supergiant stage of evolution. Not only must there be sufficient energy released from the orbit to unbind the common envelope, but it is also necessary that a sufficiently steep density gradient exist above the evolved core of the giant. If these conditions are satisfied, the time scale for orbital decay in the region above the core exceeds the time scale for mass loss from the common envelope and merger is avoided. The implications of these results for the formation of cataclysmic variables (CVs), low-mass X-ray binaries (LMXBs), and the descendants of high-mass X-ray binaries (HMXBs) are discussed.

The SALT Transient Programme

2017 ◽  
Vol 14 (S339) ◽  
pp. 176-180
Author(s):  
D. A. H. Buckley
Keyword(s):  
Gamma Ray ◽  
Cataclysmic Variables ◽  
Gamma Ray Bursts ◽  
High Mass ◽  
Core Collapse ◽  
Tidal Disruption ◽  
X Ray ◽  
Wide Range ◽  
X Ray Binaries

AbstractThe SALT transient follow-up programme began in 2016 and will continue for 5 semesters (until 31 Oct 2018), with an expectation of renewal thereafter. It is currently the only SALT Large Science Programme, and was awarded ~250 ksec. per semester, with a significant fraction (60%) given for the highest priority target-of-opportunity time. The aim is to characterise and study transients across a wide range of classes, currently including (from closest to most distant) cataclysmic variables, novæ and other associated eruptive variables, low- and high-mass X-ray binaries, OGLE and Gaia transients (including tidal disruption events), super-luminous and unusual core-collapse supernovæ, kilonovæ and other candidate optical counterparts to gravitational-wave events, flaring blazars and AGN, and gamma-ray bursts. This programme currently involves four SALT partners, of which South Africa is the major contributor of time (74%) and resources and includes five institutions with over 30 co-investigators. This talk reviewed the nature of the programme and highlighted some of the results to date.

scholarly journals Accreting magnetars: a new type of high-mass X-ray binaries?

2012 ◽  
Vol 425 (1) ◽  
pp. 595-604 ◽  
Author(s):  
P. Reig ◽  
J. M. Torrejón ◽  
P. Blay
Keyword(s):  
High Mass ◽  
X Ray ◽  
New Type ◽  
X Ray Binaries

scholarly journals The formation of high-mass black holes in low-mass X-ray binaries

New Astronomy ◽  
1999 ◽  
Vol 4 (4) ◽  
pp. 313-323 ◽  
Author(s):  
G.E. Brown ◽  
C.-H. Lee ◽  
Hans A. Bethe
Keyword(s):  
Black Holes ◽  
High Mass ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

scholarly journals X-ray sources in Galactic globular clusters and old open clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 367-376
Author(s):  
Maureen van den Berg
Keyword(s):  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Star Clusters ◽  
Open Clusters ◽  
Encounter Rate ◽  
X Ray ◽  
Low Mass ◽  
New Perspective ◽  
X Ray Binaries ◽  
Cluster Age

AbstractThe features and make up of the population of X-ray sources in Galactic star clusters reflect the properties of the underlying stellar environment. Cluster age, mass, stellar encounter rate, binary frequency, metallicity, and maybe other properties as well, determine to what extent we can expect a contribution to the cluster X-ray emission from low-mass X-ray binaries, millisecond pulsars, cataclysmic variables, and magnetically active binaries. Sensitive X-ray observations withXMM-Newton and certainlyChandra have yielded new insights into the nature of individual sources and the effects of dynamical encounters. They have also provided a new perspective on the collective X-ray properties of clusters, in which the X-ray emissivities of globular clusters and old open clusters can be compared to each other and to those of other environments. I will review our current understanding of cluster X-ray sources, focusing on star clusters older than about 1 Gyr, illustrated with recent results.

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