Dinesh Raut

Research Scholar
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: Cosmology; Epoch of Reionization; Structure Formation; Cosmological Parameter Estimation


Dinesh V. Raut obtained a B.Tech. in Engineering Physics from the Indian Institute of Technology, Mumbai, and then a Masters in Physics from the Massachusetts Institute of Technology, Cambridge, USA. He later worked on theoretical cosmology at the University of Illinois at Urbana-Champaign. After briefly working as a Lecturer, he joined NCRA-TIFR as a Research Scholar in August 2014, and is now carrying out his doctoral research under the supervision of Tirthankar Roy Choudhury. Dinesh is interested in various aspects of cosmology and has earlier worked on cosmological parameter estimation.

Research description:

Currently my research is mainly focussed on the Epoch of Reionization (EoR), which is regarded as one of the main challenges in modern cosmology. This epoch can be studied by looking at statistical information in the redshifted 21cm line emitted from neutral hydrogen. Ideally one would like to study the epoch and constrain various astrophysical processes from it. The problem is the presence of strong radio signals from the Milky Way itself and active galactic nuclei at lower redshifts, which are several orders of magnitude larger than the EoR signal. These foreground signals make it very very difficult to detect the EoR in 21cm emission, let alone extract cosmological information from it. There are 2 main ways devised to tackle the problem, both of which are based on the expected smooth behaviour of the foreground signals as a function of frequency. In the foreground modelling approach, one carefully models the frequency dependence of the foregrounds and subtracts them out from the total signal. In the foreground avoidance approach, the analysis is done in the 2-D Fourier space, where the foregrounds are confined to a wedge-shaped region. The signal, which rapidly fluctuates as a function of frequency, is not confined to the same region as the foregrounds. My work so far has involved measuring the effect of the foreground avoidance method on the 21 cm signal power spectrum from EoR. As one cannot measure the signal in the wedge-shaped foreground dominated region, one needs to be careful while interpreting the observational data. I am working on a prescription which can help to faithfully extract the cosmological information from this limited EoR signal.

Selected publications:

1. Measuring the reionization 21 cm fluctuations using clustering wedges (D. Raut, T. Roy Choudhury, & R. Ghara 2018, MNRAS, 475, 438)