School of Physics CRA Seminar - Dr. Emrah Kalemci

Speaker: Dr. Emrah Kalemci

Host: Dr. Matthew Liska

Title: Dust Scattering Halo of black hole binary 4U 1630-47 Observed with Chandra and APEX: Using mm and X-ray Imaging to Constrain Source and Molecular Cloud Distances

Abstract: 

Dust scattering halos have been utilized to study spectral variations during eclipses, physical properties and distribution of dust grains in the interstellar medium (ISM), X-ray extinction, and source distance determination using X-ray flux evolution and radial distribution of X-ray rings. We have obtained a Chandra image of the dust scattering halo of 4U 1630-47 and used it together with low-resolution 12CO images and determined the source to be 11.5 kpc in Kalemci et al. 2018.  We recently obtained very high-resolution mm images (12CO and 13CO) with the Atacama Pathfinder Experiment (APEX)  of the region. We used machine learning tools to obtain a 3-dimensional mapping of clouds in the line of sight, however, the clouds could be at their near, or far distance estimates based on their radial velocities. We generated many halo images placing the clouds at near and far distances and compared them with the actual halo image to constrain not only the source distance but also the distribution of molecular clouds in the line of sight. This method has the potential to constrain distances to compact objects behind large column densities for which the traditional methods might fail.