Related papers: Broadband Spectro-temporal Study on Blazar TXS 170…
We report on broadband observations of CTA 102 ($z=1.037$) during the active states in 2016-2017. In the $\gamma$-ray band, Fermi LAT observed several prominent flares which followed a harder-when-brighter behavior: the hardest photon index…
Among the blazars whose emission has been detected up to very-high-energy (VHE; 100 GeV < E < 100 TeV) gamma rays, intermediate synchrotron-peaked BL Lacs (IBLs) are quite rare. The IBL B2 1811+31 (z = 0.117) exhibited intense flaring…
We present the results of the power spectral density (PSD) analysis for the blazars Mrk\,421 and PKS\,2155$-$304, using good-quality, densely sampled light curves at multiple frequencies, covering 17 decades of the electromagnetic spectrum,…
We report the results from our study of the blazar S5 1803+784 carried out using the quasi-simultaneous $B$, $V$, $R$, and $I$ observations from May 2020 to July 2021 on 122 nights. Our observing campaign detected the historically bright…
Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares. With a decade of observations from the Fermi-LAT and…
Multiwavelength (MWL) observations of the blazar PKS 2155-304 during two weeks in July and August 2006, the period when two exceptional flares at very high energies (VHE, E>= 100 GeV) occurred, provide a detailed picture of the evolution of…
This paper presents the gamma-ray spectral and timing results from the long-term regular observations of Mrk 421 with the Large Area Telescope (LAT) onboard Fermi during 2008 August - 2023 August. We discerned six periods the relatively…
The BL Lac object S5~0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in…
BL Lacertae is a blazar known for its high flux variability and occasional broadband flares of unknown origin. It was in an extended flaring state from July 2020 until the end of 2021, making it an ideal candidate to study spectral and…
Blazars are promising sources of extragalactic high-energy astrophysical neutrinos, detected at energies $\gtrsim 10$ TeV by the IceCube neutrino observatory. Here, we report the first-ever broadband timing and spectral study of the…
PKS 1510-089 is one of the most variable blazars in the third Fermi-LAT source catalog. During 2015, this source has shown four flares identified as flare A, B, C, and D in between three quiescent states Q1, Q2, and Q3. The multi-wavelength…
In November 2023, the Fermi Large Area Telescope detected a $\gamma$-ray flare from the high-redshift blazar GB6 B1428+4217 ($z=4.715$). We initiated a multi-wavelength follow-up campaign involving Swift, NuSTAR, the Sierra Nevada and…
The results of a long-term multiwavelength study of the powerful flat spectrum radio quasar 3C 454.3 using {\it Fermi}-LAT and Swift XRT/UVOT data are reported. In the $\gamma$-ray band, {\it Fermi}-LAT observations show several major…
We performed a long-term optical (B, V, R bands), infra-red (J and K bands) and radio band (15, 22, 37 GHz band) study on the flat spectrum radio quasar, 3C 454.3, using the data collected over a period of more than 8 years (MJD…
We present the results from a multiwavelength campaign on the TeV blazar 1ES 1959+650, performed in May, 2006. Data from the optical, UV, soft- and hard-X-ray and very high energy (VHE) gamma-ray (E > 100 GeV) bands were obtained with the…
Here we report on the results of the WEBT photo-polarimetric campaign targeting the blazar S5~0716+71, organized in March 2014 to monitor the source simultaneously in BVRI and near IR filters. The campaign resulted in an unprecedented…
We conducted a multi-wavelength monitoring campaign of the blazar S5 0716+714 from 2022 November 26 to 2023 May 28 using optical telescopes in Egypt and Bulgaria. Data were taken during 84 nights in 11 of which intranight monitoring was…
In this work, we analyzed the long term gamma-ray data by a Fermi Large Area Telescope (Fermi-LAT) of blazar S2 0109+22, ranging from 2008 to 2023. The quasi-periodic oscillations (QPOs) of blazars aided in investigating the physical…
Electromagnetic radiation from blazar jets often displays strong variability, extending from radio to $\gamma$-ray frequencies. In a few cases, this variability has been characterized using Fourier time lags, such as those detected in the…
J1415+1320 is a well-studied blazar that exhibits strong flux density variability at a wide range of radio frequencies (2.4 $-$ 230~GHz). In this letter, we present a variability study of this source at 327~MHz using the data obtained with…