相关论文: 30 years of multi-wavelength observations of 3C 27…

We present the results of the multi-wavelength campaigns on 3C 273 in 1993-1995. During the observations in late 1993 this quasar showed an increase of its flux for energies greater equal 100 MeV from about 2.1 x 10^-7 photons/cm^2/s to…

We present an update of 3C 273's database hosted by the ISDC, completed with data from radio to gamma-ray observations over the last 10 years. We use this large data set to study the multiwavelength properties of this quasar,especially…

To understand the Active Galactic Nuclei (AGN) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and…

The aim of this paper is to study the evolution of the broadband spectrum of one of the brightest and nearest quasars 3C 273. We analyze the data obtained during quasi-simultaneous INTEGRAL and XMM monitoring of the blazar 3C 273 in…

We analyze the long-term evolution of the fluxes of six active galactic nuclei (AGN) - 0923+392, 3C 111, 3C 273, 3C 345, 3C 454.3, and 3C 84 - in the frequency range 80-267 GHz using archival calibration data of the IRAM Plateau de Bure…

During the period July 2007 - January 2009, the AGILE satellite, together with several other space- and ground-based observatories monitored the activity of the flat-spectrum radio quasar 3C 454.3, yielding the longest multiwavelength…

We have presented an optical monitoring of 3C 273, the first quasar discovered fifty years ago. It does not show variability both on intra-night and long-term time scales. To facilitate the further monitoring of 3C 273, we compiled the…

I present an overview of observational studies of quasars of all types, with particular emphasis on X-ray observational studies. The presentation is based on the most popularly accepted unified picture of quasars - collectively referred to…

We report the results of a 3-weeks multi-wavelength campaign on the flat spectrum radio quasar 3C 273 carried out with the AGILE gamma-ray mission, covering the 30 MeV -50 GeV and 18-60 keV, the REM observatory (covering the near-IR and…

We report on an XMM-Newton observation of the z=1.055 quasar and Giga-hertz Peaked Spectrum (GPS) source 3C 287. Our 62.3 ksec observation provides an exceptional X-ray view of a prominent member of this important subclass of active…

We present results from a 244\,ks \textit{NuSTAR} observation of 3C\,273 obtained during a cross-calibration campaign with the \textit{Chandra}, \textit{INTEGRAL}, \textit{Suzaku}, \textit{Swift}, and \textit{XMM-Newton} observatories. We…

We investigate the flux intensities spanning from radio waves to $\gamma$-rays across 36 light curves of Quasar 3C 273, utilizing publicly available data collected by the Integral Science Data Centre (ISDC) database. Our analysis reveals a…

Thanks to the wide field of view of its gamma-ray imager, the AGILE satellite obtained a long term monitoring of the brightest blazars in the sky and during the first 3 years of operation detected several blazars in a high gamma-ray state:…

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…

Presented in this work is the most comprehensive INTEGRAL AGN sample: it includes 272 active galaxies for which optical identifications and redshifts are available. 2-10 keV fluxes and column density measurements are also collected for all…

Active Galactic Nuclei (AGN) are ideal sources for multi-wavelength studies as their emission can cover almost 20 orders of magnitude in frequency from the radio to the gamma-ray band. After reviewing their basic properties, I will assess…

We present and make publicly available the third data release (DR3) of the Keck Observatory Database of Ionized Absorption toward Quasars (KODIAQ) survey. KODIAQ DR3 consists of a fully-reduced sample of 727 quasars at 0.1 < z < 6.4…

Gaia DR3 contains 1.8 billion sources with G-band photometry, 1.5 billion of which with BP and RP photometry, complemented by positions on the sky, parallax, and proper motion. The median number of field-of-view transits in the three…

We present multiwavelength light curves and polarimetric data of the Flat Spectrum Radio Quasar 3C 273 over 8 years. The wavelength range of our data set extends from radio to gamma-rays. We found that the optical emission in this source is…

Results of the first two years of observations using the All Sky Automated Survey prototype camera are presented. More than 140 000 stars in 50 Selected Fields covering 300 sq. degrees were monitored each clear night in the I-band resulting…