* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Home -> Astronomy News -> Stars/galaxy News -> HMXB
Post Info TOPIC: HMXB
Blobrana


L

Posts: 131433
Date:
HMXBs
Permalink  
 

Title: The ephemeris, orbital decay, and masses of 10 eclipsing HMXBs
Author: M. Falanga, E. Bozzo, A. Lutovinov, J. M. Bonnet-Bidaud, Y. Fetisova, J. Puls

We take advantage of more than 10 years of monitoring of the eclipsing HMXB systems LMC X-4, Cen X-3, 4U 1700-377, 4U 1538-522, SMC X-1, IGR J18027-2016, Vela X-1, IGR J17252-3616, XTE J1855-026, and OAO 1657-415 with the ASM on-board RXTE and ISGRI on-board INTEGRAL to update their ephemeris. These results are used to refine previous measurements of the orbital period decay of all sources (where available) and provide the first accurate values of the apsidal advance in Vela X-1 and 4U 1538-522. Updated values for the masses of the neutron stars hosted in the ten HMXBs are also provided, as well as the long-term lightcurves folded on the sources best determined orbital parameters. These lightcurves reveal complex eclipse ingresses and egresses, that are understood mostly as being due to the presence of accretion wakes. The results reported in this paper constitute a database to be used for population and evolutionary studies of HMXBs, as well as theoretical modelling of long-term accretion in wind-fed X-ray binaries.

Read more (1666kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

High mass X-ray binaries trace the Milky Way's spiral arms

Our Galaxy is littered with pairs of massive stars, many of which contain the remnants of supernova explosions. A new study of these X-ray emitting binary systems, using data from ESA's INTEGRAL space observatory, has made it possible to reconstruct the locations of the Milky Way's spiral arms many millions of years ago.
High mass X-ray binaries (HMXBs) contain stars which consume their hydrogen and helium fuel so quickly that they explode as supernovas within a few tens of millions of years - the blink of an eye in the history of the Universe.
Read more



__________________
Blobrana


L

Posts: 131433
Date:
High Mass X-ray Binaries
Permalink  
 

Title: The Distribution of High Mass X-ray Binaries in the Milky Way
Authors: Alexis Coleiro, Sylvain Chaty

Observations of the high energy sky, particularly with the INTEGRAL satellite, have quadrupled the number of supergiant X-ray Binaries observed in the Galaxy, and revealed new populations of previously hidden High Mass X-ray Binaries (HMXBs), raising new questions about their formation and evolution. The number of detected HMXBs of different types is now high enough to allow us to carry out a statistical analysis of their distribution in the Milky Way. For the first time, we derive the distance and absorption of a sample of HMXBs using a Spectral Energy Distribution fitting procedure, and we examine the correlation with the distribution of Star Forming Complexes (SFCs) in the Galaxy. We show that HMXBs are clustered with SFCs with a typical cluster size of 0.3 ± 0.05 kpc and a characteristic distance between clusters of 1.7 ± 0.3 kpc. Furthermore, we present an investigation of the expected offset between the position of spiral arms and HMXBs, allowing us to constrain age and migration distance due to supernova kick for 13 sources. These new methods will allow us to assess the influence of the environment on these high energy objects with unprecedented reliability.

Read more (940kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
RE: HMXB
Permalink  
 

Title: A new look at spherical accretion in High Mass X-ray Binaries
Authors: N. R. Ikhsanov, L. A. Pustil'nik, N. G. Beskrovnaya

Currently used model of spherical accretion onto a magnetised rotating neutron star encounters major difficulties in explaining the entry rate of accreting material into the stellar field and spin evolution of long-period X-ray pulsars. These difficulties can be, however, avoided if the magnetic field of the material captured by the neutron star is incorporated into the model. The magnetic field of the flow itself under certain conditions controls the accretion process and significantly affects the parameters of the accreting material. The mode by which the accretion flow enters the stellar magnetosphere in that case can be associated with Bohm (or turbulent) diffusion and the torque applied to the neutron star appears to be substantially higher than that evaluated in the non-magnetised accretion scenario.

Read more (41kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
High Mass X-ray Binaries
Permalink  
 

Title: Nature, formation and evolution of High Mass X-ray Binaries
Authors: Sylvain Chaty

The aim of this review is to describe the nature, formation and evolution of the three kinds of high mass X-ray binary (HMXB) population: i. systems hosting Be stars (BeHMXBs), ii. systems accreting the stellar wind of supergiant stars (sgHMXBs), and iii. supergiant stars overflowing their Roche lobe. There are now many new observations, from the high-energy side (mainly from the INTEGRAL satellite), complemented by multi-wavelength observations (mainly in the optical, near and mid-infrared from ESO facilities), showing that a new population of supergiant HMXBs has been recently revealed. New observations also suggest the existence of evolutionary links between Be and stellar wind accreting supergiant X-ray binaries. I describe here the observational facts about the different categories of HMXBs, discuss the different models of accretion in these sources (e.g. transitory accretion disc versus clumpy winds), show the evidences of a link between different kinds of HMXBs, and finally compare observations with population synthesis models.

Read more (284kb, PDF)



__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

High-mass X-ray binaries
Desig.   Name         R.A.(2000) Dec.(2000)   Mag  

2157+49  V2175 Cyg   22:01:38.2  +50:10:04.6  8.8  
2204+54  2206+543    22:07:56.2  +54:31:06.4  9.9  
0140+60B V831 Cas    01:47:00.2  +61:21:23.7  11.3 
0434+41  RXJ0440.9+  04:40:59.3  +44:31:49.3  10.8 
0515+37  V420 Aur    05:22:35.2  +37:40:33.6  7.5  
0630+05B SAXJ0635+0  06:35:18.3  +05:33:06.3  12.8



__________________
Blobrana


L

Posts: 131433
Date:
Gamma-ray Binaries
Permalink  
 

Title: The Orbits of the Gamma-ray Binaries LS I +61 303 and LS 5039
Authors: Christina Aragona, M. Virginia McSwain, Erika D. Grundstrom, Amber N. Marsh, Rachael M. Roettenbacher, Katelyn M. Hessler, Tabetha S. Boyajian, Paul S. Ray
(Version v2)

LS I +61 303 and LS 5039 are two of only a handful of known high mass X-ray binaries (HMXBs) that exhibit very high energy emission in the MeV-TeV range, and these "gamma-ray binaries" are of renewed interest due to the recent launch of the Fermi Gamma-ray Space Telescope. Here we present new radial velocities of both systems based on recent red and blue optical spectra. Both systems have somewhat discrepant orbital solutions available in the literature, and our new measurements result in improved orbital elements and resolve the disagreements. The improved geometry of each orbit will aid in studies of the high energy emission region near each source.

Read more  (389kb, PDF)

__________________
Blobrana


L

Posts: 131433
Date:
SXP18.3
Permalink  
 

Title: High mass X-ray binary SXP18.3 undergoes the longest Type II outburst ever seen in the Small Magellanic Cloud
Authors: M.P.E. Schurch, M.J. Coe, J.L. Galache, R.H.D. Corbet, K.E. McGowan, V.A. McBride, L.J. Townsend, A. Udalski, F. Haberl

On 30th August 2006 SXP18.3 a high mass X-ray binary (HMXB) in the Small Magellanic Cloud (SMC) with an 18.3s pulse period was observed by Rossi X-ray Timing Explorer (RXTE). The source was seen continuously for the following 36 weeks. This is the longest Type II outburst ever seen from a HMXB in the SMC. During the outburst SXP18.3 was located from serendipitous XMM-Newton observations. The identification of the optical counterpart has allowed SXP18.3 to be classified as a Be/X-ray binary. This paper will report on the analysis of the optical and weekly RXTE X-ray data that span the last 10 years. The extreme length of this outburst has for the first time enabled us to perform an extensive study of the pulse timing of an SMC Be/X-ray binary. We present a possible full orbital solution from the pulse timing data. An orbital period of 17.79d is proposed from the analysis of the OGLE III light curve placing SXP18.3 on the boundary of known sources in the Corbet diagram.

Read more (790kb, PDF)


__________________
Blobrana


L

Posts: 131433
Date:
RE: HMXB
Permalink  
 

Title: Suzaku Observations of Four Heavily Absorbed HMXBs
Authors: D.C. Morris, R.K. Smith, C.B. Markwardt, R.F. Mushotzky, J. Tueller, T.R. Kallman, K.S. Dhuga

We report on Suzaku observations of four unidentified sources from the INTEGRAL and Swift BAT Galactic plane surveys. All the sources have a large neutral hydrogen column density and are likely members of an emerging class of heavily absorbed high mass X-ray binary (HMXB) first identified in INTEGRAL observations. Two of the sources in our sample are approximately constant flux sources, one source shows periodic variation and one source exhibited a short, bright X-ray outburst. The periodicity is transient, suggesting it is produced by a neutron star in an elliptical orbit around a stellar wind source. We analyse the flaring source in several segments to look for spectral variation and discuss the implications of the findings for the nature of the source. We conclude that all four sources in our sample can be identified with the emerging class of highly absorbed HMXBs, that one is a newly identified transient X-ray pulsar and that at least one is a newly identified supergiant fast X-ray transient (SFXT).

Read more (110kb, PDF)

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

ESAs orbiting gamma-ray observatory, Integral has revealed a new population of exotic and dusty binary stars which might represent a brief evolutionary period in a binary stars life. The findings bring to light a gap in our knowledge of the formation and evolution of such binary star systems.
 Since 2002, when Integral was launched, the observatory has been surveying the galaxy, looking for sources of the most powerful X-rays and gamma rays. Fifteen of its new discoveries appeared to be so-called supergiant high-mass X-ray binaries (HMXB). These binary systems consist of a neutron star orbiting around a supergiant star. Before Integral, only seven supergiant HMXBs were known.
The supergiant star is at least 20 times larger than the Sun, contains 30 solar masses, with luminosity one million times greater and a temperature of 20 000 K. The neutron star was once a massive star itself, but has reached the end of its life and collapsed into a tiny stellar remnant just 15 km across.

Read more

__________________
Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.
Home -> Astronomy News -> Stars/galaxy News -> HMXB


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard