相关论文: The long-lasting activity of 3C 454.3. GASP-WEBT a…

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…

We report the results of decade-long (2008-2018) $\gamma$-ray to 1 GHz radio monitoring of the blazar 3C 279, including GASP/WEBT, $\it{Fermi}$ and $\it{Swift}$ data, as well as polarimetric and spectroscopic data. The X-ray and…

We present the results of our study of cross-correlations between long-term multi-band observations of the radio variability of the blazar 3C 279. More than a decade (2008-2022) of radio data were collected at seven different frequencies…

In July 2007, the blazar 3C 454.3 underwent a flare in the optical, reaching R~13 on July 19. Then the optical flux decreased by one magnitude, being R~14 when the source was detected by the gamma-ray satellite AGILE, that observed the…

This is the first report of Fermi Gamma-ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope (LAT), covering 2008 July 7 -…

Detailed investigation of broadband flux variability in the blazar 3C 273 allows us to probe the location and size of emission regions and their physical conditions. We report the results on correlation studies of the flaring activity…

The flat-spectrum radio quasar 3C 345 has been showing gamma-ray activity since the mid-2000s along with activity across the electromagnetic spectrum. A gamma-ray burst in 2009 was successfully linked to relativistic outflow in 43 GHz VLBI…

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 source behaviour in the period 2007-2015, characterized by…

The long term broadband spectral study of Flat Spectrum Radio Quasars during different flux states has the potential to infer the emission mechanisms and the cause of spectral variations. To scrutinize this, we performed a detailed…

In the first week of December 2009, the blazar 3C 454.3 became the brightest high energy source in the sky. Its photon flux reached and surpassed the level of 1e-5 ph/cm2/s above 100 MeV. The Swift satellite observed the source several…

We present the light curve data of a remarkable blazer 3C 454.3 (z=0.859) in optical, X-ray, and gamma-ray bands. Since January 2008, we have been monitoring this object using the 50 cm MITSuME, a optical telescope, and detected several…

[Abridged] We report on a multiwavelength observation of the blazar 3C 454.3 (which we dubbed "crazy diamond") carried out on November 2007 by means of the astrophysical satellites AGILE, INTEGRAL, Swift, the WEBT Consortium, and the…

We monitored the flaring blazar 3C 454.3 during 2005 June-July with the Spitzer Infrared Spectrograph (IRS: 15 epochs), Infrared Array Camera (IRAC: 12 epochs) and Multiband Imaging Photometer (MIPS: 2 epochs). We also made Spitzer IRS,…

Aims: 3C345 was recently identified as a gamma-ray emitter, based on the first 20 months of Fermi-LAT data and optical monitoring. In this paper, a connection between the gamma-ray and optical variability of 3C345 and properties of its…

We have undertaken a nearly simultaneous optical/UV and X-ray variability study of the flat spectrum radio quasar, 3C 273 using data available from the XMM$-$Newton satellite mission from June 2000 to July 2012. Here we focus on the…

We present multi-epoch optical observations of the blazar 3C 454.3 (z = 0.859) from 2008 August through 2011 December, using the SMARTS Consortium 1.5m+RCSpectrograph and 1.3m+ANDICAM in Cerro Tololo, Chile. The spectra reveal that the…

We focus on the exceptional flaring activity of 3C 454.3 in November 2010 and we discuss a theoretical framework addressing all data in their overall evolution. For two weeks the source has shown a plateau of enhanced GeV emission preceding…

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 gamma-rays and soft X-rays, though all peaked at nearly…

3C 454.3 is a flat spectrum radio quasar (FSRQ) known for its high variability across the electromagnetic spectrum, showing structural and flux variability in its pc-scale jet, and correlated variability among frequency bands. This study…

Blazars show optical and $\gamma$-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data at optical,…