MUNA Lunch Talk:

Sanchayeeta Borthakur

Johns Hopkins University

Effects of Starburst in the Circumgalactic and Interstellar Medium of the Galaxies

October 22

12:10PM, Room 230, NRAO, Edgemont Road


The interstellar medium (ISM) and the circum-galactic medium (CGM- gas up to ~200 kpc) are the two primary gas reservoirs for galaxies. I'll present two studies aimed at studying how the central starburst in a galaxy influences nearby ISM as well as the distant CGM.

The first part of the talk I'll discuss a project is aimed at understanding properties of the CGM of the starburst galaxies using UV absorption spectroscopy using background QSOs. In this study, we compare the properties of halo gas at ~200 kpc from the starburst galaxies to gas at similar distances in normal & passive galaxies with similar stellar masses. We find a much larger incidence rate of hot gas as traced by CIV in starburst galaxies, suggesting a global heat up of the CGM on the time-scale of ~100 - a few 100 Myrs.

In the second part of the talk, I'll focus on a UV spectral study of a set of low-z (z~0.1-0.25) starburst galaxies with properties similar to high-z Lyman-break galaxies. I'll talk about the evidence indicating the presence of a very young stellar population (3-5 Myrs old) and provide indirect evidence for the presence of holes in the ISM of these galaxies. This may help in understanding the long-standing puzzle of how Lyman continuum photons may be escaping from starburst galaxies.