Journal Club


"The evolutionary predictions in the advanced LIGO/Virgo era"

Krzysztof Belczynski (Astronomical Observatory, University of Warsaw)

We will show our most recent predictions for direct detection of gravitational waves with the advanced LIGO/Virgo. LIGO has already resumed its operations after 5 years of break. The increased sensitivity of the instrument will either very quickly bring detections (as predicted by our past and present calculations) or will deliver severe constraints on stellar and binary evolution.

Based on Belczynski et al. arxiv (2015) and recent works by Chris Belczynski, Michal Dominik, Wojtek Gladysz, Grzegorz Wiktorowicz, Mira Grudzinska and Bartosz Beldycki.


"Black hole accretion and wind"

Feng Yuan (Shanghai Astronomical Observatory, China)

Black hole hot accretion flows are perhaps operating in the nuclei of most of the galaxies in our universe. In this talk, I will review the main progress in recent years in this field, which is about the wind or outflow. The progresses are mainly attributed to the rapid development of numerical simulations of accretion flows. The following topics will be covered: theoretically why we believe strong winds exist; where and how they are produced and accelerated; what are their main properties such as mass flux and velocity; the comparison of the properties between wind and jet; the main observational evidences for wind, mainly from Sgr A*; and one observational manifestation of the interaction between wind and interstellar medium, namely the formation of the Fermi bubbles in the Galactic center.


"Long term observations of X-ray binaries with All Sky Monitors: Some new studies"

Syeda Nazma Islam (Raman Research Institute India)

I will describe some new studies carried out using long term light curves of X-ray binaries with various X-ray all sky monitors. 16 years of RXTE-ASM light-curves are utilised to construct multiple snapshots of X-ray Luminosity Functions (XLF) of the X-ray binaries in the Milky Way and study the effect of variability of X-ray binaries on them. Using orbital phase resolved spectroscopic measurements of the bright High Mass X-ray binary GX 301-2 with an unprecedented orbital coverage with MAXI, we examined various models about the mode of accretion on to the neutron star. The orbital period evolution of the eclipsing X-ray binary 4U 1700-37 was measured using long term light-curves obtained with the all sky monitors RXTE–ASM, Swift–BAT and MAXI–GSC. We have also used the mid-eclipse times and the eclipse duration measurements obtained from 10 years long X-ray light curve obtained with Swift–BAT to separately put constraints on the eccentricity of the binary system and attempted to measure any apsidal motion. The orbital intensity profile of another X-ray binary IGR J16393-4643 created with Swift-BAT shows it to have a short eclipse, which is used to constrain the inclination of this system. I will also describe the various payloads onboard the recently launched Indian multi-wavelength astronomy mission ASTROSAT.