activity
19952026
most citedLimits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars

335 citations · 8.1k across the 221 of their papers we have counts for

collaborators

223 papers

astro-ph.GA2026

Multiple H I 21-cm absorbers towards blazar PKS 1158+007

Abhisek Mohapatra, R. Srianand, R. Dutta

We report an interesting line of sight towards the blazar PKS 1158+007 (J1201+0028) ( = 1.369), revealing the rare detection of two intervening HI 21-cm absorption syst…

astro-ph.GA2026

High-S/N Quasar Observations with HST/COS: Deep Fields for Spectroscopy

Andrew J. Fox, Jerry Kriss, Philipp Richter +49

Hubble is still in prime observing condition for making transformative discoveries in UV astronomy. In this white paper we describe the science case for a deep (S/N>30) UV spectros…

astro-ph.GA2026

Investigating the Circumgalactic Medium through Mg II absorption coincidence

Paryag Sharma, Raghunathan Srianand, Hum Chand +1

We present a statistical measurement of the transverse coherence of Mg II absorption using a large sample of 9204 absorber-centric quasar sightline pairs from t…

astro-ph.GA2026

Cosmic Chance Superpositions: Largest Catalog of Quasar-Galaxy Pairs at a Projected Separation of kpc

Labanya Kumar Guha, Raghunathan Srianand, Rajeshwari Dutta

We present the largest catalogue to date of Galaxies On Top Of Quasars (GOTOQs), systems where the sightline to a background quasar passes directly through or very close to a foreg…

astro-ph.GA2025★ 4 cited

Quasar radiation transforms the gas in a merging companion galaxy

Sergei Balashev, Pasquier Noterdaeme, Neeraj Gupta +7

Quasars, powered by gas accretion onto supermassive black holes, rank among the most energetic objects of the Universe. While they are thought to be ignited by galaxy mergers and a…

astro-ph.GA2025★ 1 cited

HI 21-cm Absorption Associated with Foreground Galaxies on Top of Quasars

Labanya Kumar Guha, Raghunathan Srianand, Rajeshwari Dutta

A systematic search for HI 21-cm absorption in Quasar-Galaxy Pairs (QGPs) provides a powerful means to map the distribution of cold gas around high-redshift star-forming galaxies.…