143 citations · 896 across the 61 of their papers we have counts for
21 papers · 1 filter
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…
Multi-wavelength picture of the misaligned BL Lac object 3C 371
J. Otero-Santos, C. M. Raiteri, A. Tramacere +52
The BL Lac object 3C 371 is one of the targets that are regularly monitored by the Whole Earth Blazar Telescope (WEBT) Collaboration to study blazar variability on both short and l…
Optical variability of the blazar 3C 371: from minute to year timescales
J. Otero-Santos, C. M. Raiteri, J. A. Acosta-Pulido +41
The BL Lac object 3C 371 has been observed by the Transiting Exoplanet Survey Satellite (\textit{TESS}) for approximately a year, between July 2019 and July 2020, with an unmatched…
The variability patterns of the TeV blazar PG 1553+113 from a decade of MAGIC and multi-band observations
MAGIC Collaboration, H. Abe, S. Abe +264
PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To b…
Extreme photometric and polarimetric variability of blazar S4 0954+65 at its maximum optical and -ray brightness levels
C. M. Raiteri, M. Villata, M. I. Carnerero +64
In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and -ray bands. We present optical photometri…
Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES~2344+514
H. Abe, S. Abe, V. A. Acciari +232
The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron SED peak energy above 1keV). While those extreme states were so fa…
The optical behaviour of BL Lacertae at its maximum brightness levels: a blend of geometry and energetics
C. M. Raiteri, M. Villata, S. G. Jorstad +13
In 2021 BL Lacertae underwent an extraordinary activity phase, which was intensively followed by the Whole Earth Blazar Telescope (WEBT) Collaboration. We present the WEBT optical…
Multi-band Optical Variability of the TeV Blazar PG 1553+113 in 2019
Vinit Dhiman, Alok C. Gupta, Sofia O. Kurtanidze +20
We report the flux and spectral variability of PG 1553+113 on intra-night (IDV) to short-term timescales using BVRI data collected over 91 nights from 28 February to 8 November 201…
Investigation of the correlation patterns and the Compton dominance variability of Mrk 421 in 2017
MAGIC Collaboration, V. A. Acciari, S. Ansoldi +284
We present a detailed characterisation and theoretical interpretation of the broadband emission of the paradigmatic TeV blazar Mrk 421, with special focus on the multi-band flux co…
Unravelling the complex behavior of Mrk 421 with simultaneous X-ray and VHE observations during an extreme flaring activity in April 2013
MAGIC collaboration, V. A. Acciari, S. Ansoldi +237
We report on a multi-band variability and correlation study of the TeV blazar Mrk 421 during an exceptional flaring activity observed from 2013 April 11 to 2013 April 19. The study…
Multiwavelength behaviour of the blazar 3C279: decade-long study from -ray to radio
V. M. Larionov, S. G. Jorstad, A. P. Marscher +84
We report the results of decade-long (2008-2018) -ray to 1 GHz radio monitoring of the blazar 3C 279, including GASP/WEBT, and data, as well as polarim…
The beamed jet and quasar core of the distant blazar 4C 71.07
C. M. Raiteri, M. Villata, M. I. Carnerero +5
The object 4C 71.07 is a high-redshift blazar whose spectral energy distribution shows a prominent big blue bump and a strong Compton dominance. We present the results of a two-yea…
Optical Variability of TeV Blazars on long time-scales
Haritma Gaur, Alok C. Gupta, R. Bachev +12
We present the results of photometric observations of three TeV blazars, 3C 66A, S5 0954+658 and BL Lacertae, during the period 2013--2017. Our extensive observations were performe…
Multi-Band Intra-Night Optical Variability of BL Lacertae
Haritma Gaur, Alok C. Gupta, R. Bachev +5
We monitored BL Lacertae frequently during 2014 - 2016 when it was generally in a high state. We searched for intra-day variability for 43 nights using quasi-simultaneous measureme…
Dissecting the long-term emission behaviour of the BL Lac object Mrk 421
M. I. Carnerero, C. M. Raiteri, M. Villata +4
We report on long-term multi-wavelength monitoring of blazar Mrk 421 by the GASP-WEBT collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the sou…
Intra-night variability of the blazar CTA 102 during its 2012 and 2016 giant outbursts
R. Bachev, V. Popov, A. Strigachev +6
We obtained and analyzed more than 100 hours of multicolour optical time series of the blazar CTA 102 during its 2012 and 2016 outbursts. The object reached almost 11-th mag at the…
Exceptional outburst of the blazar CTA 102 in 2012: The GASP-WEBT campaign and its extension
V. M. Larionov, M. Villata, C. M. Raiteri +49
After several years of quiescence, the blazar CTA 102 underwent an exceptional outburst in 2012 September-October. The flare was tracked from gamma-ray to near-infrared frequencies…
Multiwavelength Study of Quiescent States of Mrk 421 with Unprecedented Hard X-Ray Coverage Provided by NuSTAR in 2013
M. Baloković, D. Paneque, G. Madejski +305
We present coordinated multiwavelength observations of the bright, nearby BL Lac object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, V…
Optical-NIR variability of blazars on diverse timescales
A. Agarwal, A. C. Gupta
To search for optical variability on a wide range of timescales, we have carried out photometric monitoring of 3C 454.3, 3C 279 and S5 0716+714. CCD magnitudes in B, V, R and I pas…
First NuSTAR Observations of Mrk 501 within a Radio to TeV Multi-Instrument Campaign
A. Furniss, K. Noda, S. Boggs +273
We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 1 April and 10 August 2013, including the first detailed characterization of the s…
The awakening of BL Lacertae: observations by Fermi, Swift, and the GASP-WEBT
C. M. Raiteri, M. Villata, F. D'Ammando +4
Since the launch of the Fermi satellite, BL Lacertae has been moderately active at gamma-rays and optical frequencies until May 2011, when the source started a series of strong fla…