335 citations · 1.6k across the 54 of their papers we have counts for
58 papers
Weak-emission-line quasars: A new clue from their optical variability
Ritish Kumar, Gopal-Krishna, Hum Chand +1
Weak-emission-line QSOs (WLQs) are an enigmatic subclass of the QSO population, as their optical/UV spectra are marked by abnormally weak (or absent) emission lines. To obtain much…
Intranight optical monitoring of the rare quasar J0950+5128, the brightest known candidate for transition from radio-quiet to radio-loud state
Krishan Chand, Gopal-Krishna, Hum Chand
We report a novel pilot project to characterise intra-night optical variability (INOV) of an extremely rare type of quasar, which has recently been caught in the act of transiting…
Exploring the AGN Accretion Disks using Continuum Reverberation Mapping
Vivek Kumar Jha, Ravi Joshi, Jayesh Saraswat +3
In the innermost regions of Active Galactic Nuclei (AGN), matter is understood to be flowing onto the Supermassive black hole (SMBH), which forms an accretion disk. This disk is re…
Intranight optical variability of TeV blazars with parsec-scale jets dominated by slow-moving radio knots
Vibhore Negi, Gopal-Krishna, Hum Chand +1
BL Lac objects detected at TeV energies preferentially belong to the subclass called 'high-frequency-peaked' BL Lacs (HBLs). Parsec-scale radio jets in these TeV-HBLs often show do…
Intranight Optical Variability of Blazars and Radio-quiet Quasars using the ZTF Survey
Vibhore Negi, Gopal-Krishna, Ravi Joshi +4
We explore the potential of the ongoing Zwicky-Transient-Facility (ZTF) survey for studying Intra-Night Optical Variability (INOV) of active galactic nuclei (AGN), in particular fo…
The transience and persistence of high optical polarization state in beamed radio quasars
Krishan Chand, Gopal-Krishna, Amitesh Omar +2
We examine the long-term stability (on decade-like time scales) of optical `high polarization' (HP) state with , which commonly occurs in flat-spectrum (i.e., beam…