scholarly journals Possible detection of a new cyclotron feature in 4U 1700–37

2020 ◽  
Vol 493 (2) ◽  
pp. 3045-3053
Author(s):  
Suman Bala ◽  
Jayashree Roy ◽  
Dipankar Bhattacharya
Keyword(s):  
Compact Object ◽  
Periodic Oscillation ◽  
High Mass ◽  
Emission Region ◽  
Frequency Range ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Line Feature ◽  
Transient Source ◽  
Cyclotron Line

ABSTRACT We present a spectral and timing study of the high-mass X-ray binary transient source 4U 1700–37 using NuSTAR and ASTROSAT/LAXPC. The source is observed in two different flux states. A combined spectral analysis of NuSTAR’s focal plane modules A and B shows the possible hint of a cyclotron line feature at ∼16 keV. The line feature is consistently present in different continuum models with at least 3σ confidence level. We do not detect the presence of a previously reported  39 keV cyclotron line in the combined spectra. A ∼16 keV cyclotron feature would suggest that the compact object is a neutron star with a magnetic field strength ∼2.1 × 1012 G in the emission region. We also find the presence of a rare Ni Kα emission line around 7.6 keV in the NuSTAR spectrum. We searched the NuSTAR and ASTROSAT data for coherent or quasi-periodic oscillation signals but found no evidence in the frequency range 0.1 mHz to 103 Hz.

scholarly journals Stellar Winds in Massive X-ray Binaries

2016 ◽  
Vol 12 (S329) ◽  
pp. 355-358
Author(s):  
Peter Kretschmar ◽  
Silvia Martínez-Núñez ◽  
Enrico Bozzo ◽  
Lidia M. Oskinova ◽  
Joachim Puls ◽  
...  
Keyword(s):  
Compact Object ◽  
High Mass ◽  
Stellar Winds ◽  
X Rays ◽  
X Ray ◽  
Current State ◽  
Wide Range ◽  
Strong Winds ◽  
The One ◽  
X Ray Binaries

AbstractStrong winds from massive stars are a topic of interest to a wide range of astrophysical fields. In High-Mass X-ray Binaries the presence of an accreting compact object on the one side allows to infer wind parameters from studies of the varying properties of the emitted X-rays; but on the other side the accretor’s gravity and ionizing radiation can strongly influence the wind flow. Based on a collaborative effort of astronomers both from the stellar wind and the X-ray community, this presentation attempts to review our current state of knowledge and indicate avenues for future progress.

scholarly journals The Nature of the Compact Object in the Hard X-Ray Source 4U2206+54

2004 ◽  
Vol 194 ◽  
pp. 208-208
Author(s):  
J. M. Torrejón ◽  
I. Kreykenbohni ◽  
A. Orr ◽  
L. Titarchuk ◽  
I. Negueruela
Keyword(s):  
Neutron Star ◽  
Accretion Disk ◽  
Compact Object ◽  
High Energy ◽  
Energy Data ◽  
X Ray ◽  
Hot Plasma ◽  
Cyclotron Line ◽  
First Time

We present an analysis of archival RXTE and BeppoSAX data of the X-ray source 4U2206+54. For the first time, high energy data (≥ 30 keV) is analyzed. The data is well described by comptonization models in which seed photons with temperatures between 1.1 keV arid 1.5 keV are comptonized by a hot plasma at 50 keV thereby producing a hard tail which extends up to 100 keV. From luminosity arguments it is shown that the area of the soft photons source must be small (r ≈ 1 km) and that the presence of an accretion disk in this system is unlikely. Here we report on the possible existence of a cyclotron line around 30 keV . The presence of a neutron star in the system is strongly favored by the available data.

Discovery of an ∼7 H[CLC]z[/CLC] Quasi-periodic Oscillation in the Low-Luminosity Low-Mass X-Ray Binary 4U 1820−30

1999 ◽  
Vol 512 (1) ◽  
pp. L39-L42 ◽  
Author(s):  
Rudy Wijnands ◽  
Michiel van der Klis ◽  
Erik-Jan Rijkhorst
Keyword(s):  
Periodic Oscillation ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Low Mass

Modeling of hydrodynamic processes within high-mass X-ray binaries

2018 ◽  
Vol 14 (S346) ◽  
pp. 197-201
Author(s):  
Petr Kurfürst ◽  
Jiří Krtička
Keyword(s):  
Mass Loss Rate ◽  
Compact Object ◽  
Supernova Explosion ◽  
High Mass ◽  
Be Stars ◽  
X Ray ◽  
Hydrodynamic Processes ◽  
Hydrodynamic Structure ◽  
X Ray Binaries ◽  
Circumstellar Environment

AbstractHigh-mass X-ray binaries belong to the brightest objects in the X-ray sky. They usually consist of a massive O or B star or a blue supergiant while the compact X-ray emitting component is a neutron star (NS) or a black hole. Intensive matter accretion onto the compact object can take place through different mechanisms: wind accretion, Roche-lobe overflow, or circumstellar disk. In our multi-dimensional models we perform numerical simulations of the accretion of matter onto a compact companion in case of Be/X-ray binaries. Using Bondi-Hoyle-Littleton approximation, we estimate the NS accretion rate. We determine the Be/X-ray binary disk hydrodynamic structure and compare its deviation from isolated Be stars’ disk. From the rate and morphology of the accretion flow and the X-ray luminosity we improve the estimate of the disk mass-loss rate. We also study the behavior of a binary system undergoing a supernova explosion, assuming a blue supergiant progenitor with an aspherical circumstellar environment.

scholarly journals Kink instabilities in relativistic jets can drive quasi-periodic radiation signatures

2020 ◽  
Vol 494 (2) ◽  
pp. 1817-1825
Author(s):  
Lingyi Dong ◽  
Haocheng Zhang ◽  
Dimitrios Giannios
Keyword(s):  
Large Scale ◽  
Magnetic Energy ◽  
Surrounding Medium ◽  
Periodic Oscillation ◽  
Polarization Degree ◽  
Growth Time ◽  
Emission Region ◽  
Relativistic Jets ◽  
Quasi Periodic Oscillation ◽  
Central Engine

ABSTRACT Relativistic jets are highly collimated plasma outflows emerging from accreting black holes. They are launched with a significant amount of magnetic energy, which can be dissipated to accelerate non-thermal particles and give rise to electromagnetic radiation at larger scales. Kink instabilities can be an efficient mechanism to trigger dissipation of jet magnetic energy. While previous works have studied the conditions required for the growth of kink instabilities in relativistic jets, the radiation signatures of these instabilities have not been investigated in detail. In this paper, we aim to self-consistently study radiation and polarization signatures from kink instabilities in relativistic jets. We combine large-scale relativistic magnetohydrodynamic (RMHD) simulations with polarized radiation transfer of a magnetized jet, which emerges from the central engine and propagates through the surrounding medium. We observe that a localized region at the central spine of the jet exhibits the strongest kink instabilities, which we identify as the jet emission region. Very interestingly, we find quasi-periodic oscillation (QPO) signatures in the light curve from the emission region. Additionally, the polarization degree appears to be anticorrelated to flares in the light curves. Our analyses show that these QPO signatures are intrinsically driven by kink instabilities, where the period of the QPOs is associated with the kink growth time-scale. The latter corresponds to weeks to months QPOs in blazars. The polarization signatures offer unique diagnostics for QPOs driven by kink instabilities.

scholarly journals Wind Roche lobe overflow in high-mass X-ray binaries

2019 ◽  
Vol 622 ◽  
pp. L3 ◽  
Author(s):  
I. El Mellah ◽  
J. O. Sundqvist ◽  
R. Keppens
Keyword(s):  
Mass Transfer ◽  
Compact Object ◽  
Stellar Mass ◽  
Roche Lobe ◽  
High Mass ◽  
Transfer Rates ◽  
X Ray ◽  
Accretion Rates ◽  
Mass Outflow ◽  
X Ray Binaries

Ultraluminous X-ray sources (ULXs) have such high X-ray luminosities that they were long thought to be accreting intermediate-mass black holes. Yet, some ULXs have been shown to display periodic modulations and coherent pulsations suggestive of a neutron star in orbit around a stellar companion and accreting at super-Eddington rates. In this Letter, we propose that the mass transfer in ULXs could be qualitatively the same as in supergiant X-ray binaries (SgXBs), with a wind from the donor star highly beamed towards the compact object. Since the star does not fill its Roche lobe, this mass transfer mechanism known as “wind Roche lobe overflow” can remain stable even for large donor-star-to-accretor mass ratios. Based on realistic acceleration profiles derived from spectral observations and modeling of the stellar wind, we compute the bulk motion of the wind to evaluate the fraction of the stellar mass outflow entering the region of gravitational predominance of the compact object. The density enhancement towards the accretor leads to mass-transfer rates systematically much larger than the mass-accretion rates derived by the Bondi-Hoyle-Lyttleton formula. We identify orbital and stellar conditions for a SgXBs to transfer mass at rates necessary to reach the ULX luminosity level. These results indicate that Roche-lobe overflow is not the only way to funnel large quantities of material into the Roche lobe of the accretor. With the stellar mass-loss rates and parameters of M101 ULX-1 and NGC 7793 P13, wind Roche-lobe overflow can reproduce mass-transfer rates that qualify an object as an ULX.

scholarly journals CI Camelopardalis: The first sgB[e]-high mass X-ray binary twenty years on: A supernova imposter in our own Galaxy?

2019 ◽  
Vol 622 ◽  
pp. A93 ◽  
Author(s):  
E. S. Bartlett ◽  
J. S. Clark ◽  
I. Negueruela
Keyword(s):  
Variable Mass ◽  
Compact Object ◽  
Small Population ◽  
High Mass ◽  
Circumstellar Envelope ◽  
Local Conditions ◽  
Single Star ◽  
X Ray ◽  
Circumstellar Extinction ◽  
Binary Evolution

Context. The Galactic supergiant B[e] star CI Camelopardalis (CI Cam) was the first sgB[e] star detected during an X-ray outburst. The star brightened to ∼2 Crab in the X-ray regime (∼5 × 10−8 ergs cm−2 s−1 in the 2–25 keV range) within hours before decaying to a quiescent level in less than two weeks, clearly indicative of binarity. Since the outburst of CI Cam, several sgB[e] stars have been identified as X-ray overluminous for a single star (i.e. LX >  10−7 Lbol). This small population has recently expanded to include two ultra luminous X-ray sources (ULX), Holmberg II X-1 and NGC 300 ULX-1/supernova imposter SN2010da. Aims. Since the discovery of X-ray emission from CI Cam, there have been many developments in the field of massive binary evolution. In light of the recent inclusion of two ULXs in the population of X-ray bright sgB[e] stars, we revisit CI Cam to investigate its behaviour over several timescales and shed further light on the nature of the compact object in the system, its X-ray outburst in 1998 and the binary system parameters. Methods. We analysed archival XMM-Newton EPIC-pn spectra and light curves along with new data from Swift and NuSTAR. We also present high-resolution (R ∼ 85 000) Mercator/HERMES optical spectra, including a spectrum taken 1.02 days after our NuSTAR observation. Results. Despite being in quiescence, CI Cam is highly X-ray variable on timescales of days, both in terms of total integrated flux and spectral shape. We interpret these variations by invoking the presence of an accreting compact companion immersed in a dense, highly structured, aspherical circumstellar envelope. The differences in the accretion flux and circumstellar extinction represent either changes in this environment, triggered by variable mass loss from the star, or the local conditions to the accretor due to its orbital motion. We find no evidence for pulsations in the X-ray light curve. Conclusions. CI Cam has many similarities with SN2010da across mid-IR, optical and X-ray wavelengths suggesting that, subject to distance determination for CI Cam, if CI Cam was located in an external galaxy its 1998 outburst would have led to a classification as a supernova imposter.

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