scholarly journals SPECTRAL AND TIMING NATURE OF THE SYMBIOTIC X-RAY BINARY 4U 1954+319: THE SLOWEST ROTATING NEUTRON STAR IN AN X-RAY BINARY SYSTEM

2014 ◽  
Vol 786 (2) ◽  
pp. 127 ◽  
Author(s):  
Teruaki Enoto ◽  
Makoto Sasano ◽  
Shin'ya Yamada ◽  
Toru Tamagawa ◽  
Kazuo Makishima ◽  
...  
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
X Ray

scholarly journals Torque Reversals in Disk Accreting Pulsars

1998 ◽  
Vol 15 (2) ◽  
pp. 250-253
Author(s):  
Jianke Li ◽  
Dayal T. Wickramasinghe
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Recent Work ◽  
Time Scale ◽  
Accretion Rate ◽  
Future Studies ◽  
X Ray ◽  
The Past ◽  
X Ray Binaries ◽  
Coherent Picture

AbstractX-ray binaries in which the accreting component is a neutron star commonly exhibit significant changes in their spin. In the system Cen X-3, a disk accreting binary system, the pulsar was observed to spin up at a rate ḟ = 8 × 10−13 Hz s−1 when averaged over the past twenty years, but significant fluctuations were observed above this mean. Recent BASTE observations have disclosed that these fluctuations are much larger than previously noted, and appeared to be a system characteristic. The change in the spin state from spin-up to spin-down or vice-versa occurs on a time scale that is much shorter than the instrument can resolve (≤1 d), but appears always to be a similar amplitude, and to occur stochastically. These observations have posed a problem for the conventional torque–mass accretion relation for accreting pulsars, because in this model the spin rate is closely related to the accretion rate, and the latter needs to be finely tuned and to change abruptly to explain the observations. Here we review recent work in this direction and present a coherent picture that explains these observations. We also draw attention to some outstanding problems for future studies.

scholarly journals Recycling in progress: RXTE discovery of the first accretion-powered millisecond pulsar

2000 ◽  
Vol 177 ◽  
pp. 643-648
Author(s):  
M. van der Klis
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Binary System ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Radio Pulsar ◽  
Millisecond Pulsar ◽  
X Ray ◽  
Millisecond Radio

AbstractThe discovery is reported of the first accretion-powered millisecond pulsar, SAX J 1808.4–3658. This 2.5 millisecond pulsar has a magnetic field strength of 1–10108Gauss and has all the characteristics of the long-predicted millisecond radio pulsar progenitor, a neutron star in an X-ray binary system where the process of recycling is taking place at this time.

scholarly journals Spin-up/spin-down of neutron star in Be-X-ray binary system GX 304-1

2014 ◽  
Vol 446 (1) ◽  
pp. 1013-1019 ◽  
Author(s):  
K. A. Postnov ◽  
A. I. Mironov ◽  
A. A. Lutovinov ◽  
N. I. Shakura ◽  
A. Yu. Kochetkova ◽  
...  
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
X Ray

scholarly journals Swift J011511.0-725611: discovery of a rare Be star/white dwarf binary system in the SMC

2021 ◽  
Vol 508 (1) ◽  
pp. 781-788
Author(s):  
J A Kennea ◽  
M J Coe ◽  
P A Evans ◽  
L J Townsend ◽  
Z A Campbell ◽  
...  
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
South African ◽  
White Dwarf ◽  
Compact Object ◽  
Type Ii ◽  
Large Telescope ◽  
X Ray ◽  
Be Star

ABSTRACT We report on the discovery of Swift J011511.0-725611, a rare Be X-ray binary system (BeXRB) with a white dwarf (WD) compact object, in the Small Magellanic Cloud (SMC) by S-CUBED, a weekly X-ray/UV survey of the SMC by the Neil Gehrels Swift Observatory. Observations show an approximately 3 month outburst from Swift J011511.0-725611, the first detected by S-CUBED since it began in 2016 June. Swift J011511.0-725611 shows supersoft X-ray emission, indicative of a WD compact object, which is further strengthened by the presence of an 0.871 keV edge, commonly attributed to O viii K-edge in the WD atmosphere. Spectroscopy by South African Large Telescope confirms the Be nature of the companion star, and long term light curve by OGLE finds both the signature of a circumstellar disc in the system at outburst time, and the presence of a 17.4 day periodicity, likely the orbital period of the system. Swift J011511.0-725611 is suggested to be undergoing a Type-II outburst, similar to the previously reported SMC Be white dwarf binary (BeWD), Swift J004427.3-734801. It is likely that the rarity of known BeWD is in part due to the difficulty in detecting such outbursts due to both their rarity, and their relative faintness compared to outbursts in Neutron Star BeXRBs.

scholarly journals X-Rays Radiation of a Neutron Star as a Result of Gas Accretion

1968 ◽  
Vol 1 ◽  
pp. 216-219
Author(s):  
Ja. B. Zel’dovič
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Internal Energy ◽  
The Other ◽  
X Rays ◽  
Intergalactic Gas ◽  
X Ray ◽  
Radiation Spectra ◽  
Energetic Balance ◽  
Gas Accretion

The accretion of gas on the surface of a neutron star is a source of energy, which can be converted into X-rays radiation. Accretion can ascertain a far greater lifetime of an X-ray star than the radiation of internal energy.The source of gas could be a cloud of intergalactic gas. If the neutron star is a component of a binary system, the gas could come from the other (non-neutronic) star.The idea of accretion and evaluation of energetic balance were given by Zel’dovič (1964) and Zel’dovič and Novikov (1964, 1965) and Salpeter (1964). Shortly the idea of accretion was mentioned by Šklovskij (1967).The motion of gas and radiation spectra idealised case of spheric symmetry are studied now by N. Shakuro and Zel’dovič.

scholarly journals Origin of High Velocity Pulsar and Soft Gamma Ray Repeaters

1996 ◽  
Vol 160 ◽  
pp. 359-360
Author(s):  
Hitoshi Hanami
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
High Velocity ◽  
Relative Velocity ◽  
Gamma Ray ◽  
Center Of Mass ◽  
Supernova Explosion ◽  
Close Binary System ◽  
Close Binary ◽  
X Ray

AbstractWe consider a close binary system with separation ≃ 0.2 R⊙which consists of a (C+O) star of mass ≃ 4 M⊙and a neutron star as a progenitor of soft gamma-ray repeater (SGR) and a high velocity pulsar. After the event of the supernova explosion, both new and old neutron stars have high relative velocity of ≃ 1000km s−1to the center of mass of the ejecta. SGR activities can be induced by the episodic accretion of the supernova ejecta onto the old neutron star or the strange high rotating pulsar of the new neutron star. Future observations with fine positional resolution can clarify the position ambiguity between the gamma ray and X-ray sources.

scholarly journals The newly discovered Be/X-ray binary Swift J004516.6–734703 in the SMC: witnessing the emergence of a circumstellar disc

2020 ◽  
Vol 499 (1) ◽  
pp. L41-L46
Author(s):  
J A Kennea ◽  
M J Coe ◽  
P A Evans ◽  
I M Monageng ◽  
L J Townsend ◽  
...  
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Light Curves ◽  
Type I ◽  
Pulsation Period ◽  
X Ray ◽  
Tidal Interaction ◽  
Long Period ◽  
Periodicity Analysis ◽  
Ir Light

ABSTRACT We report on the discovery of Swift J004516.6–734703, a Be/X-ray binary system by the Swift SMC Survey, S-CUBED. Swift J004516.6–734703, or SXP 146.6, was found to be exhibiting a bright (∼1037 erg s−1) X-ray outburst on 2020 June 18. The historical UV and IR light-curves from OGLE and Swift/UVOT showed that after a long period of steady brightness, it experienced a significant brightening beginning around 2019 March. This IR/UV rise is likely the signature of the formation of a circumstellar disc, confirmed by the presence of strong an H α line in SALT spectroscopy, that was not previously present. Periodicity analysis of the OGLE data reveals a plausible 426 d binary period, and in X-ray a pulsation period of 146.6 s is detected. The onset of X-ray emission from Swift J004516.6–734703 is likely the signature of a Type-I outburst from the first periastron passage of the neutron star companion through the newly formed circumstellar disc. We note that the formation of the circumstellar disc began at the predicted time of the previous periastron passage, suggesting its formation was spurred by tidal interaction with the neutron star.

Long-term optical variability of Her X-1

2018 ◽  
Vol 14 (S346) ◽  
pp. 239-241
Author(s):  
T. İçli ◽  
D. Koçak ◽  
K. Yakut
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Orbital Period ◽  
Optical Variability ◽  
National Observatory ◽  
Short Term ◽  
X Ray ◽  
Robotic Telescope

AbstractLong-term and short-term multicolor photometric variations of the X-ray binary system Her X-1 (HZ Her) has been studied. We obtained new VRI observations of the system by using the 60cm Robotic telescope at the TÜBİTAK National Observatory (TUG) in 2018. Using newly obtained data, we modified the orbital period of the binary system with a neutron star component.

Comparison of the X-Ray Sources CIR X-1. GX301-2 and 2S0535-668

1980 ◽  
Vol 4 (1) ◽  
pp. 108-111 ◽  
Author(s):  
M. L. Duldig ◽  
R. M. Thomas ◽  
R. F. Haynes
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Strong Evidence ◽  
Compact Object ◽  
Eccentric Orbit ◽  
X Ray

There is reasonably strong evidence to suggest that the periodic X-ray, radio and optical variable Cir X-1 is a highly eccentric orbit (e ~ 0.8), binary system comprising an OB supergiant primary and a compact object, probably a neutron star (Whelan et al. 1977; Haynes, Lerche and Murdin 1980).

scholarly journals Observations of GRO J1744–28 in quiescence with XMM-Newton

2020 ◽  
Vol 643 ◽  
pp. A62
Author(s):  
V. Doroshenko ◽  
V. Suleimanov ◽  
S. Tsygankov ◽  
J. Mönkkönen ◽  
L. Ji ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Binary System ◽  
Galactic Center ◽  
Optical Counterpart ◽  
X Ray ◽  
Upper Limit ◽  
Dipole Term ◽  
The Magnetic Field

We report on the deep observations of the “bursting pulsar” GRO J1744–28, which were performed with XMM-Newton and aimed to clarify the origin of its X-ray emission in quiescence. We detect the source at a luminosity level of ∼1034 erg s−1 with an X-ray spectrum that is consistent with the power law, blackbody, or accretion-heated neutron star atmosphere models. The improved X-ray localization of the source allowed us to confirm the previously identified candidate optical counterpart as a relatively massive G/K III star at 8 kpc close to the Galactic center, implying an almost face-on view of the binary system. Although we could only find a nonrestricting upper limit on the pulsed fraction of ∼20%, the observed hard X-ray spectrum and strong long-term variability of the X-ray flux suggest that the source is also still accreting when not in outburst. The luminosity corresponding to the onset of centrifugal inhibition of accretion is thus estimated to be at least two orders of magnitude lower than previously reported. We discuss this finding in the context of previous studies and argue that the results indicate a multipole structure in the magnetic field with the first dipole term of ∼1010 G, which is much lower than previously assumed.

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