88 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Aryabhatta Research Institute of Observational SciencesIN13 papers
- Indian Institute of AstrophysicsIN6 papers
- Inter-University Centre for Astronomy and AstrophysicsIN6 papers
- Deen Dayal Upadhyaya Gorakhpur UniversityIN5 papers
- Saha Institute of Nuclear PhysicsIN5 papers
- University of DelhiIN5 papers
- Center for Excellence in Basic SciencesIN3 papers
- Kavli Institute for Theoretical SciencesCN3 papers
- Peking UniversityCN3 papers
- Central University of JammuIN2 papers
- Kumaun UniversityIN2 papers
- Physical Research LaboratoryIN2 papers
13 papers · 1 filter
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…
Brightness and colour variability in NLSy1s
Madhu Sudan, Hum Chand, Paul J. Wiita +1
The Zwicky Transient Facility (ZTF), with its extensive optical monitoring capabilities, has provided an unprecedented opportunity to study the long-term variability of active gala…
Circumgalactic medium of quasar host galaxies at 0.4<z<0.8 probed by strong Mg II absorption
Paryag Sharma, Raghunathan Srianand, Hum Chand +1
Using a sample of 166 projected quasar pairs we investigate the influence of active galactic nuclei on the circumgalactic medium (CGM) of the quasar host galaxies probed using stro…
Evidence of under-developed torus and broad-line region of weak emission line quasars based on their spectral energy distribution
Ritish Kumar, Hum Chand, Ravi Joshi
To unravel the dominant cause of the weak emission line in a subset of optically selected radio-quiet 'weak emission line quasars' (WLQs), we have investigated the possibility of a…
A comparative study of the physical properties for a representative sample of Narrow and Broad-line Seyfert galaxies
Vivek Kumar Jha, Hum Chand, Vineet Ojha +2
We present a comparative study of the physical properties of a homogeneous sample of 144 Narrow line Seyfert 1 (NLSy1) and 117 Broad-line Seyfert 1 (BLSy1) galaxies. These two samp…
Intranight variability of UV emission from powerful blazars
Krishan Chand, Gopal-Krishna, Amitesh Omar +4
We report the first study to characterise intranight variability of the blazar class from the perspective of (rest-frame) UV emission. For this, we carried out intranight optical m…
Optical Flux and Colour Variability of Blazars in the ZTF Survey
Vibhore Negi, Ravi Joshi, Krishan Chand +4
We investigate the temporal and colour variability of 897 blazars, comprising 455 BL Lacertae objects (BL Lacs) and 442 Flat Spectrum Radio Quasars (FSRQs), selected from the Roma-…
Accretion Disk Sizes from Continuum Reverberation Mapping of AGN Selected from the ZTF Survey
Vivek Kumar Jha, Ravi Joshi, Hum Chand +4
We present the accretion disk size estimates for a sample of 19 active galactic nuclei (AGN) using the optical , , and band light curves obtained from the Zwicky Transien…
A Search for Blazar Activity in Broad-Absorption-Line Quasars
Sapna Mishra, Gopal-Krishna, Hum Chand +3
Our recently reported lack of Intra-Night Optical Variability (INOV) among Broad-Absorption-Line (BAL) quasars exhibiting some blazar-like radio properties, either questions polar…
Appearance vs Disappearance of broad absorption line troughs in quasars
Sapna Mishra, M. Vivek, Hum Chand +1
We present a new set of 84 Broad absorption line (BAL) quasars ( 1.7 \zem 4.4) exhibiting an appearance of \civ BAL troughs over 0.34.8 rest-frame years by comparing the…
Intra-night optical variability of ray detected narrow-line Seyfert 1 galaxies
Vineet Ojha, Hum Chand, Gopal-Krishna
We report the first attempt to systematically characterise intra-night optical variability (INOV) of the rare and enigmatic subset of Narrow-Line Seyfert1 galaxies (NLSy1s), which…
Comparative intra-night optical variability of X-ray and -ray detected narrow-line Seyfert 1 galaxies
Ojha Vineet, Chand Hum, Gopal-Krishna +2
In a systematic program to characterise the intra-night optical variability (INOV) of different classes of narrow-line Seyfert 1 galaxies (NLSy1s), we report here the first compara…
Role of intervening Mg II absorbers on the rotation measure and fractional polarisation of the background quasars
Sunil Malik, Hum Chand, T. R. Seshadri
We probed the magnetic fields in high-redshift galaxies using excess extragalactic contribution to residual rotation measure (RRM) for quasar sightlines with intervening Mg II abso…