Vikram Khaire

Visiting Fellow
National Centre for Radio Astrophysics
Tata Institute of Fundamental Research
Savitribai Phule Pune University Campus,
Pune 411 007
Maharashtra, INDIA
Status: Left

Main Research Areas: Intergalactic medium, Extragalactic background light, Hydrogen and helium reionization, Star formation history


Vikram did his B.Sc. (Physics) from Fergusson College, Pune, in 2007 and his M.Sc. (Physics) from the Physics Department, University of Pune, in 2010. After completing his Ph.D. from IUCAA in June 2016, he joined the National Centre for Radio Astrophysics as a post-doctoral fellow.

Research description:

I am mostly interested in the topics related to the intergalactic medium (IGM). My current work is focused on modeling the extragalactic background light (EBL) from extreme ultraviolet to infrared regime of the electromagnetic spectrum. The EBL is necessary ingredient to study the evolution of the IGM and its connection with galaxies, two main phase transitions of the IGM i.e hydrogen and helium reionization, the thermal history of the IGM and its implications on structure formation. It also plays an important role in studying the high energy gamma-ray sources. The EBL is contributed by stellar light emitted from galaxies and the light emitted from accretion of the matter on super-massive blackholes (quasars). The relative contribution of them determines the spectrum of the EBL at different wavelengths. My past research helped to address key questions in modelling of the EBL such as how to lift the degeneracy between star formation history and dust correction to obtain stellar light from galaxies, the escape fraction of hydrogen ionizing photons from galaxies, and the quasar contribution to the EBL. In recent time, I am working on modelling a part of the EBL that directly affects the helium in the IGM and drives the helium reionization. This will eventually lead to improve our current understanding of several interesting topics related to the physics of the IGM.

Selected publications:

1. The redshift evolution of escape fraction of hydrogen ionizing photons from galaxies (V. Khaire et al. 2016, MNRAS, 457, 4051)

2. Photon underproduction crisis: Are QSOs sufficient to resolve it? (V. Khaire & R. Srianand 2015, MNRAS, 451, L30)

3. Star formation history, dust attenuation, and extragalactic background light (V. Khaire & R. Srianand 2015, ApJ, 805, 33)

4. He II optical depth and ultraviolet escape fraction of galaxies (V. Khaire & R. Srianand 2013, MNRAS, 431, L53)