Related papers: Flaring Activity from 0836+710 (4C +71.07): What C…
We examine lengthy radio light curves of the flat spectrum radio galaxy 3C 454.3 for possible quasi-periodic oscillations (QPOs). The data used in this work were collected at five radio frequencies, 4.8, 8.0, 14.5, 22.0, and 37.0 GHz…
We report about the multi-frequency (1-30 GHz) daily monitoring of the radio flux variability of the three microquasars: SS433, GRS1915+105 and Cyg X-3 during the period from September 2005 to May 2006. 1. We detected clear correlation of…
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…
We report on the extreme gamma-ray activity from the FSRQ PKS 1510-089 observed by AGILE in March 2009. In the same period a radio-to-optical monitoring of the source was provided by the GASP-WEBT and REM. Moreover, several Swift ToO…
The flat-spectrum radio quasar B2 1633+382 (4C 38.41) has been monitored for several years and has presented correlated variability in multiple wavelengths. In this article, we are performing different analyses for multiple frequencies,…
We present BeppoSAX observations of three gamma-ray emitting quasars, namely 0836+710, 1510-089 and 2230+114. The three objects have been detected up to 100 keV showing extremely flat power-law spectra above 2 keV (energy index…
In 2012 Markarian 421 underwent the largest flare ever observed in this blazar at radio frequencies. In the present study, we start exploring this unique event and compare it to a less extreme event in 2013. We use 15 GHz radio data…
In this work, I have presented a multi-frequency variability and correlation study of the blazar Ton 599, which was observed first time in flaring state at the end of 2017. Data from \textit{Fermi}-LAT, Swift-XRT/UVOT, Steward Observatory,…
We report on the final two days of a multiwavelength campaign of Sgr A* observing in the radio, submillimeter, infrared, and X-ray bands in July 2019. Sgr A* was remarkably active, showing multiple flaring events across the electromagnetic…
Densely time sampled multi-frequency flux measurements of the extreme BL Lac object S5 0716+714 over the past three years allow us to study its broad-band variability, and the detailed underlying physics, with emphasis on the location and…
We have investigated the nature of flare emission from Sgr A* during multi-wavelength observations of this source that took place in 2004, 2005 and 2006. We present evidence for dimming of submm and radio flux during the peak of near-IR…
Following the recent discovery of gamma rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z=0.5846), we started a multiwavelength campaign from radio to gamma rays, which was carried out between the end of March and the…
Due to its powerful radiation over the entire electromagnetic spectrum and its radio jet activity, the blazar 3C273 offers the opportunity to study the physics of $\gamma$-ray emission from active galactic nuclei. Since a historically…
In the 1990s a comparison of sparse EGRET measurements with single-dish flux density monitoring from the Metsahovi and UMRAO programs established a temporal connection between the onset of flaring at radio band and the occurrence of…
CTA 102 is a $\gamma$-ray bright blazar that exhibited multiple flares in observations by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope during the period of 2016-2018. We present results from the analysis of…
The quasar-type blazar 3C 454.3 underwent a phase of high activity in summer and autumn 2007, which was intensively monitored in the radio-to-optical bands by the Whole Earth Blazar Telescope (WEBT). The gamma-ray satellite AGILE detected…
A multiwavelength temporal and spectral analysis of flares of 3C 279 during November 2017--July 2018 are presented in this work. Three bright gamma-ray flares were observed simultaneously in X-ray and Optical/UV along with a prolonged…
We continuously monitored the blazar S5 0716+714 in the optical $g$, $r$ and $i$ bands from Nov. 10, 2017 to Jun. 06, 2019. The total number of observations is 201 nights including 26973 data points. This is a very large quasi-simultaneous…
The flat-spectrum radio quasar 3C 454.3 underwent an extraordinary 5-day gamma-ray outburst in November 2010 where the daily flux measured with the Fermi Large Area Telescope (LAT) at photon energies E>100 MeV reached (66+/-2) x 10^-6 ph…
Blazars are known to show periods of quiescence followed by outbursts visible throughout the electromagnetic spectrum. We present a novel maximum likelihood approach to capture this bimodal behavior by examining blazar radio variability in…