scholarly journals Thermal winds in stellar mass black hole and neutron star binary systems

2017 ◽  
Vol 473 (1) ◽  
pp. 838-848 ◽  
Author(s):  
Chris Done ◽  
Ryota Tomaru ◽  
Tadayuki Takahashi
Author(s):  
R Pattnaik ◽  
K Sharma ◽  
K Alabarta ◽  
D Altamirano ◽  
M Chakraborty ◽  
...  

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.


Science ◽  
2018 ◽  
Vol 362 (6411) ◽  
pp. 201-206 ◽  
Author(s):  
K. De ◽  
M. M. Kasliwal ◽  
E. O. Ofek ◽  
T. J. Moriya ◽  
J. Burke ◽  
...  

Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. We report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.2 solar masses) and low kinetic energy (≈2 × 1050ergs). Early photometry and spectroscopy reveal evidence of shock cooling of an extended helium-rich envelope, likely ejected in an intense pre-explosion mass-loss episode of the progenitor. Taken together, we interpret iPTF 14gqr as evidence for ultra-stripped supernovae that form neutron stars in compact binary systems.


Author(s):  
Nils Andersson

This chapter provides a brief survey of gravitational-wave astronomy, including the recent recent breakthrough detection. It sets the stage for the rest of the book via simple back-of-the-envelope estimates for different sets of sources. The chapter also describes the first detection of a black hole merger (GW150914) as well as the first observed neutron star binary event (GW170817) and introduces some of the ideas required to understand these breakthroughs.


2006 ◽  
Author(s):  
Joshua A. Faber ◽  
Thomas W. Baumgarte ◽  
Stuart L. Shapiro ◽  
Keisuke Taniguchi ◽  
Frederic A. Rasio

2012 ◽  
Vol 08 ◽  
pp. 209-219 ◽  
Author(s):  
MAXIM V. BARKOV

In this paper we propose a new plausible mechanism of supernova explosions specific to close binary systems. The starting point is the common envelope phase in the evolution of a binary consisting of a red super giant and a neutron star. As the neutron star spirals towards the center of its companion it spins up via disk accretion. Depending on the specific angular momentum of gas captured by the neutron star via the Bondi-Hoyle mechanism, it may reach millisecond periods either when it is still inside the common envelope or after it has merged with the companion core. The high accretion rate may result in strong differential rotation of the neutron star and generation of a magnetar-strength magnetic field. The magnetar wind can blow away the common envelope if its magnetic field is as strong as 1015 G, and can destroy the entire companion if it is as strong as 1016 G. The total explosion energy can be comparable to the rotational energy of a millisecond pulsar and reach 1052 erg. The result is an unusual type-II supernova with very high luminosity during the plateau phase, followed by a sharp drop in brightness and a steep light-curve tail. The remnant is either a solitary magnetar or a close binary involving a Wolf-Rayet star and a magnetar. When this Wolf-Rayet star explodes this will be a third supernovae explosion in the same binary. A particularly interesting version of the binary progenitor involves merger of a red super giant star with an ultra-compact companion, neutron star or black hole. In the case if a strong magnetic field is not generated on the surface of a neutron star then it will collapse to a black hole. After that we expect the formation of a very long-lived accretion disk around the black hole. The Blandford-Znajek driven jet from this black hole may drive not only hypernovae explosion but produce a bright X-ray transient event on a time scale of 104 s.


2018 ◽  
Vol 97 (8) ◽  
Author(s):  
Fatemeh Hossein Nouri ◽  
Matthew D. Duez ◽  
Francois Foucart ◽  
M. Brett Deaton ◽  
Roland Haas ◽  
...  

2004 ◽  
Vol 194 ◽  
pp. 204-204
Author(s):  
J. I. González-Hernández ◽  
R. Rebolo ◽  
G. Israelian ◽  
J. Casares

We have determined abundances in the secondary stars of the black hole X-ray binary A0620-00 and the neutron star Binary Cen X-4. These are K type stars veiled by the emission produced by the respective accretion discs. We searched for evidence of nucleosynthetic products from the progenitor of the compact object that could have contaminated the secondary stars (as in Israelian et al., 1999).Using high resolution spectra obtained with VLT/UVES, we have derived in a consistent way stellar parameters and the veiling caused by the accretion disc.


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