45 citations · 175 across the 13 of their papers we have counts for
15 papers
Investigating X-ray Emission from Radio-detected Broad- and Narrow-line Seyfert 1 Galaxies
Minhua Zhou, Minfeng Gu, Lei Xu +2
Context: This paper presents a study of the X-ray emission for a sample of radio-detected (RD-) broad- and narrow-line Seyfert 1 galaxies (NLS1s and BLS1s). Aims: To investigate th…
Multi-band optical photometric variability of the blazar OJ 287 from 2015 to 2025
Alok C. Gupta, Karan Dogra, Mark Kidger +101
We present the most densely sampled multi-band optical photometric observations of the peculiar BL Lacertae object OJ 287 from 2015 to 2025 with a focus on its optical activity on…
Multiband Optical Variability of the Blazar 3C 454.3 on Diverse Timescales
Karan Dogra, Alok C. Gupta, C. M. Raiteri +79
Due to its peculiar and highly variable nature, the blazar 3C 454.3 has been extensively monitored by the WEBT team. Here, we present for the first time these long-term optical flu…
Varstrometry Selected Radio-Loud Candidates of Dual and Off-Nucleus Quasars at Sub-kpc Scales
Hao-Chen Wang, Jun-Xian Wang, Min-Feng Gu +1
Dual super massive black holes at sub-kpc to kpc scales, the product of galaxy mergers, are progenitors of eventually coalescing binary SMBHs. If both or one of the dual SMBHs are…
Intermediate-mass black holes: finding of episodic, large-scale and powerful jet activity in a dwarf galaxy
Jun Yang, Zsolt Paragi, Sándor Frey +10
Dwarf galaxies are characterised by a very low luminosity and low mass. Because of significant accretion and ejection activity of massive black holes, some dwarf galaxies also host…
Study of variability in long-term multiwavelength optical lightcurves of blazar AO 0235+164
Abhradeep Roy, Alok C. Gupta, Varsha R. Chitnis +9
We present a long-term and intraday variability study on optical multiwaveband () data from the blazar AO 0235+164 collected by various telescopes for 44 years (19…
X-ray emission of radio-loud quasar SDSS J121426.52+140258.9: independent variations between optical/UV and X-ray emission
Minhua Zhou, Minfeng Gu, Mai Liao +1
To understand the X-ray emission of active galactic nuclei (AGNs), we explored the optical-to-X-ray variation correlation of a radio-loud quasar (RLQ) SDSS J121426.52+140258.9 (her…
Exploring the Connection between UV/Optical Variations and Radio Emission in Radio-Quiet Quasars: Clues on Radio Emission Origin
Mai Liao, Junxian Wang, Wenyong Kang +1
The radio emission in radio-quiet quasars (RQQs) has been a long mystery and its physical origin remains unclear. In a previous work we find UV/optical more variable quasars have s…
Investigations on the optical properties and X-ray emission in compact radio AGN
Mai Liao, Minfeng Gu
Compact radio active galactic nuclei (compact radio AGN) are compact ( 20 kpc), powerful radio sources. Currently, the preferred scenario is that they are at the early stage…
The X-ray emission in young radio AGNs
Mai Liao, Minfeng Gu, Minhua Zhou +1
In this work, we investigated the X-ray emission for a sample of young radio AGNs by combining their data from Chandra/XMM-Newton and at other wavebands. We find strong correlation…
Investigation on Young radio AGNs based on SDSS spectroscopy
Mai Liao, Minfeng Gu
The Gigahertz Peaked Spectrum (GPS) sources, Compact Steep Spectrum (CSS) radio sources, and High Frequency Peakers (HFP) radio sources are thought to be young radio AGNs, at the e…
Long-term optical spectroscopic variations in blazar 3C 454.3
Krzysztof Nalewajko, Alok C. Gupta, Mai Liao +3
Characterisation of the long-term variations in the broad line region in a luminous blazar, where Comptonisation of broad-line emission within a relativistic jet is the standard sc…
Intra-day variability of three Seyfert Galaxies measured with XMM-Newton
Ashutosh Tripathi, Paul J. Wiita, Alok C. Gupta +2
We present and analyze the variability of three Seyfert galaxies on intra-day timescales. We have analyzed in a uniform manner the 38 longest ( ks) observations made for NGC…
A peculiar multi-wavelength flare in the Blazar 3C 454.3
Alok C. Gupta, Arun Mangalam, Paul J. Wiita +20
The blazar 3C454.3 exhibited a strong flare seen in gamma-rays, X-rays, and optical/NIR bands during 3--12 December 2009. Emission in the V and J bands rose more gradually than did…
The Optical Variability of SDSS Quasars from Multi-epoch Spectroscopy. III. A Sudden UV Cutoff in Quasar SDSS J2317+0005
Hengxiao Guo, Matthew A. Malkan, Minfeng Gu +6
We have collected near-infrared to X-ray data of 20 multi-epoch heavily reddened SDSS quasars to investigate the physical mechanism of reddening. Of these, J2317+0005 is found to b…