Anjan Kumar Sarkar
Post-Doctoral Fellow
Email: asarkar [at] ncra.tifr.res.in
Phone: 020-25719269
Extn: 9269
Office: 218B
National Centre for Radio Astrophysics
Tata Institute of Fundamental Research
Savitribai Phule Pune University Campus,
Pune 411 007
Maharashtra, INDIA
Tata Institute of Fundamental Research
Savitribai Phule Pune University Campus,
Pune 411 007
Maharashtra, INDIA
Main Research Areas: HI 21-cm Signal; Post-Reionization Era; Radio Astronomy; Statistical tools for radio astronomy; Lyman-alpha forest
Biography:
Anjan obtained his B.Sc. from Bolpur College, Bolpur,, in 2010, and his M. Sc. from Visva-Bharati University, Shantiniketan, in 2012. He then joined IIT Kharagpur for his Ph.D. in August 2012, working with Somnath Bharadwaj. He obtained his Ph.D. in 2019, and then moved to the Raman Research Institute (RRI) as a post-doctoral fellow; he was at RRI between 2019 and 2022. He joined NCRA-TIFR in May 2022, as a Visiting Fellow.Research description:
Neutral atomic hydrogen (in spectroscopic notation, HI) dominates the interstellar medium of galaxies throughout the Universe. The 21-cm spectral line, arising due to a transition of the HI atom between its ground-state hyperfine energy levels, provides a critical probe of the HI content of galaxies and the intergalactic medium. In the past couple of years, I have primarily focused on studying the prospects of detecting this 21-cm radiation from the post-reionization era, where most of the HI resides in self-shielded clouds within galaxies, identified as Damped Lyman-alpha Absorbers (DLAs) in quasar absorption spectra. The collective 21-cm emission from these HI sources appears as a radio background at frequencies below 1420 MHZ. Fluctuations in this background radiation carry the signature of the source clustering in this era. It is therefore possible to use 21-cm observation to map out the HI distribution as a function of redshift - which is believed to reliably trace the underlying matter distribution in this era at large scales. This can provide us important information about the structure and evolution of the Universe at large scales.Selected publications:
1. A. K. Sarkar , K. L. Pandey, & S. K. Sethi, "Using the redshift evolution of the Lyman-alpha effective opacity as a probe of dark matter models", 2021, JCAP, 10, 77. 2. R. Mondal, A. K. Shaw, I. T. Iliev, et al., "Predictions for measuring the 21-cm multifrequency angular power spectrum using SKA-LOW", 2020, MNRAS, 494, 4043. 3. R. Mondal, S. Bharadwaj, I. T. Iliev, et al., "A method to determine the evolution history of the mean neutral hydrogen fraction", 2019, MNRAS Letters, 483, L109. 3. A. K. Sarkar, A. K. Pal, & T. Guha Sarkar, "Constraining warm dark matter power spectrum using the cross-correlation of HI 21 cm signal and the Lyman-α forest", 2019, JCAP, 12, 58. 4. A. K. Sarkar, S. Bharadwaj, & T. Guha Sarkar, "Predictions for measuring the cross power spectrum of the HI 21-cm signal and the Lyman-α forest using OWFA", 2018, JCAP, 5, 51. 5. A. K. Sarkar, S. Bharadwaj, & V. R. Marthi, "An analytical method to simulate the HI 21-cm visibility signal for intensity mapping experiments", 2018, MNRAS, 473, 261. 6. A. K. Sarkar, S. Bharadwaj, & Sk. Saiyad Ali, "Fisher matrix-based predictions for measuring the z = 3.35 binned 21- cm power spectrum using the Ooty Wide Field Array (OWFA)", 2017, JAA, 38, 14 7. S. Bharadwaj, A. K. Sarkar, & Sk. Saiyad Ali, "Fisher matrix predictions for detecting the cosmological 21-cm signal with the Ooty Wide Field Array (OWFA)", 2015, JAA, 36, 385.
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