activity
20242026
most citedApplication of the FRADO model of BLR formation to the Seyfert galaxy NGC 5548 and the first step toward determining the Hubble constant

6 citations · 9 across the 15 of their papers we have counts for

collaborators

15 papers

astro-ph.HE2026

Multi-Band Optical Variability Characteristics of the -ray emitting blazar 1ES 0647+250 during its 2020 flare

K. Subbu Ulaganatha Pandian, C. S. Stalin, S. Muneer +4

We present a multi-band optical variability study of the -ray emitting high-synchrotron-peaked blazar 1ES~0647+250 during its enhanced optical activity in 2020. The analysis uti…

astro-ph.GA2026

Accretion-disk sizes in two quasars with interferometrically resolved broad-line regions at and

Francisco Pozo Nuñez, Eduardo Bañados, Swayamtrupta Panda +3

We present the first direct comparison between accretion-disk (AD) and broad-line region (BLR) sizes in quasars at z > 2, combining continuum reverberation mapping with interferome…

astro-ph.GA2026

HALO II: Constraining Hubble constant through continuum delay fitting of Fairall 9

Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal +28

The Hubble tension remains one of the most significant unresolved problems in modern cosmology. A key question is whether it may arise from underestimated systematic uncertainties…

astro-ph.GA2026

Consistency between X-ray and UV-Optical reverberation measurements in NGC 5548

Amit Kumar Mandal, Bożena Czerny, Michal Dovčiak +2

The hard X-rayemitting hot corona is a key component of active galaxies. Constraints on the hot corona height can be derived from reverberation studies in both the X-ray and opt…

astro-ph.GA2026

Ultraviolet variability in Radio-Loud Active Galactic Nuclei observed by UVIT onboard AstroSat

M. Reshma, C. S. Stalin, Amit Kumar Mandal +3

Radio-loud active galactic nuclei (AGN) are among the most luminous objects in the Universe, emitting radiation from low-energy radio waves to high energy -rays. They are well k…

astro-ph.GA2025★ 3 cited

HALO I: Photometric continuum reverberation mapping of Fairall 9

Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal +23

We investigate the origin of inter-band continuum time delays in active galactic nuclei (AGNs) to study the structure and properties of their accretion disks. We aim to measure the…

astro-ph.GA2025

Standardizing reverberation-mapped H active galactic nuclei using time-averaged radiusluminosity relations with 5100\,Å\,, broad H, and narrow \OIII\ luminosities

Shulei Cao, Amit Kumar Mandal, Michal Zajaček +1

Active galactic nuclei (AGN) have been studied as alternate probes in cosmology due to their large and stable luminosities and broad redshift range. Previously it was shown that hi…

astro-ph.GA2025

Spectroscopic Reverberation Mapping for SARM: The Case of Mrk 1048 and Mrk 618

Shivangi Pandey, Suvendu Rakshit, S. Muneer +14

Robust extragalactic distance measurements are crucial for resolving the persistent discrepancy in the value of the Hubble constant (H)). Active Galactic Nuclei (AGNs), through…

astro-ph.GA2025

Probing dust torus radius--luminosity relation: An WISE view

Ashutosh Tomar, Suvendu Rakshit, Amit Kumar Mandal +1

We present measurements of the dusty torus sizes of 51 active galactic nuclei (AGNs) with a redshift of 0.8. Our analysis utilizes about 16 years of optical photometric data o…

astro-ph.GA2025

Scaling Relations of the Dusty Torus with Luminosity and the Broad-Line Region

Ashraf Ayubinia, Jong-Hak Woo, Shu Wang +2

We measure and compare the size of the dusty torus with active galactic nucleus (AGN) luminosity and the size of the broad-line region (BLR), using a sample of 182 AGNs with the be…

astro-ph.GA2025

Standardizing a larger, higher-quality, homogeneous sample of reverberation-mapped H active galactic nuclei using the broad-line region radius-luminosity relation

Shulei Cao, Amit Kumar Mandal, Michal Zajaček +1

We present a high-quality, homogeneous sample of 157 H reverberation-mapped active galactic nuclei (RM AGNs) spanning redshifts , which is approximat…

astro-ph.GA2025

Seoul National University AGN Monitoring Project. V. Velocity-resolved H-beta Reverberation Mapping and Evidence of Kinematics Evolution

Shu Wang, Jong-Hak Woo, Aaron J. Barth +13

We present velocity-resolved reverberation lags of H-beta for 20 active galactic nuclei (AGNs) from the Seoul National University AGN Monitoring Project. We detect unambiguous velo…

astro-ph.GA2025

The size of the continuum emission region and its scaling relations with active galactic nucleus luminosity and the broad-line region size

Amit Kumar Mandal, Jong-Hak Woo, Shu Wang

We present a continuum lag analysis for a sample of 37 relatively high-luminosity active galactic nuclei (AGNs) from the Seoul National University AGN Monitoring Project (SAMP), ut…

astro-ph.GA2024

Standardizing reverberation-mapped H and H active galactic nuclei using radius--luminosity relations involving monochromatic and broad H luminosities

Shulei Cao, Amit Kumar Mandal, Michal Zajaček +2

We test the standardizability of a homogeneous sample of 41 lower-redshift () active galactic nuclei (AGNs) reverberation-mapped (RM) using the broad H…

astro-ph.GA2024★ 6 cited

Application of the FRADO model of BLR formation to the Seyfert galaxy NGC 5548 and the first step toward determining the Hubble constant

V. K. Jaiswal, Amit K. Mandal, R. Prince +5

The dynamical and geometric structures of the Broad Line Region (BLR), along with the origins of continuum time delays in active galaxies, remain topics of ongoing debate. In this…