Related papers: Nonextensive entropic behavior observed in Quasar …

We analyze the spectra of high temperature \fexxiv~lines observed by \emph{Hinode}/EIS during the impulsive phase of the X8.3--class flare on September 10, 2017. The line profiles are broad, show pronounced wings, and clearly depart from a…

We present absolutely calibrated FUV spectra of the quasar 3C~273 covering 900- 1800 A. Our ~3 A resolution spectra were obtained with the Hopkins Ultraviolet Telescope during the Astro-1 mission in December 1990 and during the Astro-2…

ROSAT HRI observations of 3C 273 reveal X-ray emission all along the optically visible jet with the peak of emission at the inner end. Whereas the X-ray emission from the innermost knot A is consistent with a continuation of the…

We have explored the nature of the extended emission-line region around the z=0.37 quasar 4C 37.43, using extensive ground-based and HST imaging and spectroscopy. The velocity field of the ionized gas shows gradual gradients within…

The flat-spectrum radio quasar 3C~454.3 throughout the years has presented very high activity phases (flares) in which the different wavebands increase their flux dramatically. In this work, we perform multiwavelength analysis from radio to…

We present a new approach to derive the observed properties of synchrotron outbursts in relativistic jets. The idea is to use the very well sampled submillimetre-to-radio long-term light curves of 3C 273 to extract the spectral and temporal…

We present the results of a three-week daily monitoring campaign on the quasar 3C 279 by the X-ray satellites RXTE and ROSAT. A cross correlation provides no evidence for any time lag between the very similar soft and hard X-ray light…

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,…

shortened) Results obtained from 9 X-ray observations of 3C 273 performed by ASCA are presented (for a total exposure time of about 160 000 s). The analysis and interpretation of the results is complicated by the fact that 4 of these…

We present an optical spectrum for Mrk 273x, the X-ray source 1.3' to the northeast of Mrk 273. The new spectrum indicates that the object is at a much higher redshift (0.458) than the value (0.0376) previously reported. All the detected…

We have performed infrared imaging of the jet of the quasar 3C 273 at wavelengths 3.6 and 5.8 microns with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. When combined with the radio, optical and X-ray measurements, the…

We investigate quasi-periodic pulsations (QPPs) of high-energy nonthermal emissions from an X9.3 flare (SOL2017-Sep-06T11:53), the most powerful flare since the beginning of solar cycle 24. The QPPs are identified as a series of regular and…

We have studied the temporal and spectral properties of SXP 15.3 observed by \textit{NuSTAR} in hard energy range 3-79 keV during late 2018. The timing analysis of \textit{NuSTAR} observation predicts coherent pulsation at…

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…

3C 279 showed enhanced flux variations in Fermi-LAT {\gamma}-ray observations from January to June 2018. We present a detailed Fermi-LAT analysis to investigate the variability and spectral behaviors of 3C 279 during the {\gamma}-ray flares…

Only a handful of quasars have been identified as kinetically dominated, their long term time averaged jet power, $\overline{Q}$, exceeds the bolometric thermal emission, $L_{bol}$, associated with the accretion flow. This letter presents…

We report on the {\it Chandra} discovery of large scale non--thermal emission features in the double lobed SSRL quasar 3C 207 (z=0.684). These are: a diffuse emission well correlated with the western radio lobe, a bright one sided jet whose…

This paper reports on the extreme ultraviolet (EUV) spectrum of three low redshift ($z \sim 0.6$) radio loud quasars, 3C 95, 3C 57 and PKS 0405-123. The spectra were obtained with the Cosmic Origins Spectrograph (COS) of the Hubble Space…

Here we present the study of a compact emission source during an X1.3 flare on 2022-March-30. Within a $\sim41$~s period (17:34:48 UT to 17:35:29 UT), IRIS observations show spectral lines of Mg II, C II and Si IV with extremely broadened,…

The blazar 3C 454.3 was revealed by the Fermi Gamma-ray Space Telescope to be in an exceptionally high flux state in July 2008. Accordingly, we performed a multi-wavelength monitoring campaign on this blazar using IR and optical…