scholarly journals X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
Vol 188 ◽  
pp. 388-389
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Compact Object ◽  
Optical Observations ◽  
Black Hole Mass ◽  
X Ray ◽  
Upper Limit ◽  
Supergiant Star ◽  
X Ray Binaries ◽  
Two Bodies

About 10 X-ray binaries in our Galaxy and LMC/SMC are considered to contain black hole candidates (BHCs). Among these objects, Cyg X-1 was identified as the first BHC, and it has led BHCs for more than 25 years(Oda 1977, Liang and Nolan 1984). It is a binary system composed of normal blue supergiant star and the X-ray emitting compact object. The orbital kinematics derived from optical observations indicates that the compact object is heavier than ~ 4.8 M⊙ (Herrero 1995), which well exceeds the upper limit mass for a neutron star(Kalogora 1996), where we assume the system consists of only two bodies. This has been the basis for BHC of Cyg X-1.

scholarly journals A Machine Learning Approach For Classifying Low-mass X-ray Binaries Based On Their Compact Object Nature

2020 ◽  
Author(s):  
R Pattnaik ◽  
K Sharma ◽  
K Alabarta ◽  
D Altamirano ◽  
M Chakraborty ◽  
...  
Keyword(s):  
Machine Learning ◽  
Black Hole ◽  
Neutron Star ◽  
Binary Systems ◽  
Compact Object ◽  
X Ray ◽  
Average Accuracy ◽  
Machine Learning Approach ◽  
Low Mass ◽  
X Ray Binaries

Abstract Low Mass X-ray binaries (LMXBs) are binary systems where one of the components is either a black hole or a neutron star and the other is a less massive star. It is challenging to unambiguously determine whether a LMXB hosts a black hole or a neutron star. In the last few decades, multiple observational works have tried, with different levels of success, to address this problem. In this paper, we explore the use of machine learning to tackle this observational challenge. We train a random forest classifier to identify the type of compact object using the energy spectrum in the energy range 5-25 keV obtained from the Rossi X-ray Timing Explorer archive. We report an average accuracy of 87±13% in classifying the spectra of LMXB sources. We further use the trained model for predicting the classes for LMXB systems with unknown or ambiguous classification. With the ever-increasing volume of astronomical data in the X-ray domain from present and upcoming missions (e.g., SWIFT, XMM-Newton, XARM, ATHENA, NICER), such methods can be extremely useful for faster and robust classification of X-ray sources and can also be deployed as part of the data reduction pipeline.

scholarly journals The Lense–Thirring timing-accretion plane for ULXs

2019 ◽  
Vol 489 (1) ◽  
pp. 282-296 ◽  
Author(s):  
M J Middleton ◽  
P C Fragile ◽  
A Ingram ◽  
T P Roberts
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Effective Means ◽  
Compact Object ◽  
Resonance Scattering ◽  
Phase Lag ◽  
Black Hole Mass ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Accretion Rates

ABSTRACT Identifying the compact object in ultraluminous X-ray sources (ULXs) has to date required detection of pulsations or a cyclotron resonance scattering feature (CRSF), indicating a magnetized neutron star. However, pulsations are observed to be transient and it is plausible that accretion on to the neutron star may have suppressed the surface magnetic field such that pulsations and CRSFs will be entirely absent. We may therefore lack direct means to identify neutron star systems whilst we presently lack an effective means by which to identify black hole ULXs. Here we present a possible method for separating the ULX population by assuming the X-ray, mHz quasi-periodic oscillations (QPOs), and day time-scale periods/QPOs are associated with Lense–Thirring precession of the inflow and outflowing wind, respectively. The precession time-scales combined with the temperature of the soft X-ray component produce planes where the accretor mass enters as a free parameter. Depending on the properties of the wind, use of these planes may be robust to a range in the angular momentum (spin) and, for high accretion rates, essentially independent of the neutron star’s surface dipole field strength. Our model also predicts the mHz QPO frequency and magnitude of the phase lag imprinted due to propagation through the optically thick wind; in the case of NGC 5408 X-1 we subsequently infer a black hole mass and moderate-to-high spin. Finally, we note that observing secular QPO evolution over sufficient baselines may indicate a neutron star, as the precession responds to spin-up which is not readily observable for black hole primaries.

X-Ray Determination of the Black-Hole Mass in Cygnus X-1

1998 ◽  
pp. 388-389 ◽  
Author(s):  
A. Kubota ◽  
K. Makishima ◽  
T. Dotani ◽  
H. Inoue ◽  
K. Mitsuda ◽  
...  
Keyword(s):  
Black Hole ◽  
Black Hole Mass ◽  
X Ray

scholarly journals Possible ∼0.4 h X-ray quasi-periodicity from an ultrasoft active galactic nucleus

2020 ◽  
Vol 644 ◽  
pp. L9
Author(s):  
J. R. Song ◽  
X. W. Shu ◽  
L. M. Sun ◽  
Y. Q. Xue ◽  
C. Jin ◽  
...  
Keyword(s):  
Black Hole ◽  
Active Galactic Nucleus ◽  
Quiescent State ◽  
Black Hole Mass ◽  
Resonance Model ◽  
X Ray ◽  
Galactic Black Hole ◽  
Independent Observations ◽  
Extreme Variability ◽  
X Ray Binaries

RX J1301.9+2747 is an ultrasoft active galactic nucleus (AGN) with unusual X-ray variability that is characterized by a long quiescent state and a short-lived flare state. The X-ray flares are found to recur quasi-periodically on a timescale of 13−20 ks. Here, we report the analysis of the light curve in the quiescent state from two XMM-Newton observations spanning 18.5 years, along with the discovery of a possible quasi-periodic X-ray oscillation (QPO) with a period of ∼1500 s. The QPO is detected at the same frequency in the two independent observations, with a combined significance of > 99.89%. The QPO is in agreement with the relation between frequency and black hole mass (MBH) that has been reported in previous works for AGNs and Galactic black hole X-ray binaries (XRBs). The QPO frequency is stable over almost two decades, suggesting that it may correspond to the high-frequency type found in XRBs and originates, perhaps, from a certain disk resonance mode. In the 3:2 twin-frequency resonance model, our best estimate on the MBH range implies that a maximal black hole spin can be ruled out. We find that all ultrasoft AGNs reported so far display quasi-periodicities in the X-ray emission, suggesting a possible link on the part of the extreme variability phenomenon to the ultrasoft X-ray component. This indicates that ultrasoft AGNs could be the most promising candidates in future searches for X-ray periodicities.

Binary X-ray sources in the LMC

1991 ◽  
Vol 148 ◽  
pp. 285-290 ◽  
Author(s):  
J. B. Hutchings ◽  
A. P. Cowley
Keyword(s):  
Black Hole ◽  
Point Source ◽  
Optical Observations ◽  
High Mass ◽  
X Ray ◽  
Long Period ◽  
Low Mass ◽  
Black Hole Binary ◽  
X Ray Binaries

We report new results on the X-ray binaries in the LMC since IAU Symposium 108 (see review by Hutchings 1984). These include an update of the point source identifications after further optical observations and a reprocessing of the Einstein database. We report major new results on several specific systems. Among low-mass systems (LMXB), we report periods and orbital determinations for LMC X-2 (long period), CAL 83, and CAL 87 (eclipsing black-hole binary). For the high-mass X-ray binaries (MXRB), we announce an ˜ 99 day (precession?) period in LMC X-3 and discuss orbital determinations for LMC X-1 and 0538–66.

scholarly journals Fitting along the Fundamental Plane: New comparisons of jet physics across the black hole mass scale

2010 ◽  
Vol 6 (S275) ◽  
pp. 250-254 ◽  
Author(s):  
Sera Markoff ◽  
Michael A. Nowak ◽  
Dipankar Maitra ◽  
Jörn Wilms ◽  
Elena Gallo ◽  
...  
Keyword(s):  
Black Hole ◽  
Mass Range ◽  
Mass Scale ◽  
Jet Physics ◽  
Black Hole Mass ◽  
Fundamental Plane ◽  
X Ray ◽  
Black Hole Accretion ◽  
Hard State ◽  
X Ray Binaries

AbstractCorrelations between the radio and X-ray bands in the hard state of black hole X-ray binaries (BHBs) have led to the discovery of the Fundamental Plane of black hole accretion, linking accretion-driven radiative attributes to black hole mass. Although this discovery has led to new constraints on radiative efficiencies, there is still significant degeneracy in terms of understanding the governing physics. I present several new results exploring the processes driving the Fundamental Plane over the black hole mass range. These include the first ever homogeneous fits of sources at approximately the same Eddington luminosity but millions of times different in mass, which I focus on for this proceeding article.

scholarly journals Inventory of black hole binaries

2003 ◽  
Vol 212 ◽  
pp. 365-371 ◽  
Author(s):  
Jerome A. Orosz
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Binary Systems ◽  
Compact Object ◽  
X Rays ◽  
Optical Studies ◽  
Dynamical Mass ◽  
X Ray ◽  
Black Hole Binaries ◽  
X Ray Binaries

A small group of X-ray binaries currently provides the best evidence for the existence of stellar-mass black holes. These objects are interacting binary systems where the X-rays arise from accretion of material onto a compact object (i.e., an object with a radius of less than a few hundred km). In some favourable cases, optical studies of the companion star lead to dynamical mass estimates for both components. In 17 cases, the mass of the compact object in an X-ray binary has been shown to exceed the maximum mass of a stable neutron star (about 3 M⊙), which leads to the conclusion that these objects are black holes. In this contribution I will review the basic properties of these black hole binaries.

scholarly journals Measuring the Masses of Compact Objects in Low-Mass X-Ray Binaries

2004 ◽  
Vol 194 ◽  
pp. 214-214
Author(s):  
Dawn M. Gelino
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Compact Object ◽  
Compact Objects ◽  
Orbital Inclination ◽  
X Ray ◽  
Secondary Star ◽  
Low Mass ◽  
The Masses ◽  
X Ray Binaries

Low-mass X-ray binaries (LMXBs) contain compact, black hole (BH) or neutron star (NS) primaries, and cool, low-mass secondary stars. We measure the orbital inclination of the system in quiescence by modeling infrared (IR) ellipsoidal variations from the secondary star in order to determine the compact object mass. I present our results for a few LMXBs, including the first BH that appears to conclusively fall in the 3-5 M⊙ range.

scholarly journals Clumped stellar winds in supergiant high-mass X-ray binaries

2012 ◽  
Vol 8 (S290) ◽  
pp. 287-288 ◽  
Author(s):  
L. M. Oskinova ◽  
A. Feldmeier ◽  
P. Kretschmar
Keyword(s):  
Stellar Wind ◽  
Compact Object ◽  
Time Dependent ◽  
High Mass ◽  
Stellar Winds ◽  
Degree Of Ionization ◽  
X Ray ◽  
Wind Theory ◽  
Supergiant Star ◽  
X Ray Binaries

AbstractThe clumping of massive star winds is an established paradigm, which is confirmed by multiple lines of evidence and is supported by stellar wind theory. We use the results from time-dependent hydrodynamical models of the instability in the line-driven wind of a massive supergiant star to derive the time-dependent accretion rate on to a compact object in the Bondi-Hoyle-Lyttleton approximation. The strong density and velocity fluctuations in the wind result in strong variability of the synthetic X-ray light curves. Photoionization of inhomogeneous winds is different from the photoinization of smooth winds. The degree of ionization is affected by the wind clumping. The wind clumping must also be taken into account when comparing the observed and model spectra of the photoionized stellar wind.

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