相关论文: BeppoSAX Observations of 1 Jy BL Lacertae Objects.…

Extreme High-frequency BL~Lacs (EHBL) feature their synchrotron peak of the broadband spectral energy distribution (SED) at $\nu_{\rm s} \geq $10$^{17}$\,Hz. The BL~Lac object 1ES~2344+514 was included in the EHBL family because of its…

We studied the temporal and spectral evolution of the synchrotron emission from the high energy peaked BL Lac object 1E 1207.9+3945. Two recent observations have been performed by the XMM-Newton and Swift satellites; we carried out X-ray…

We report optical, radio and X-ray observations of the Narrow-Line Seyfert 1 galaxy RX J1702.5+3247. The soft (0.1-2 keV) X-ray flux, measured by BeppoSAX, is characterized by strong variability on short time scales (< 500 sec). The most…

Previous studies on the fitting of spectral energy distributions (SEDs) often apply the external-Compton process to interpret the high-energy peak of low-synchrotron-peaked (LSP) BL Lac objects (LBLs), despite the lack of strong broad…

A very high energy (VHE) gamma-ray signal has been detected at the 5.4 sigma level from H1426+428, an x-ray selected BL Lacertae object at a redshift of 0.129. The object was monitored from 1995 - 1998 with the Whipple 10m imaging…

We report the multi-wavelength study for a high-synchrotron-peaked BL Lac 1ES 1218+304 using near-simultaneous data obtained during the period from January 1, 2018, to May 31, 2021 (MJD 58119-59365) from various instruments including…

This work is a summary of the X-ray spectral studies of 29 TeV $\gamma$-ray emitting blazars observed with Swift/XRT, especially focusing on sources for which X-ray regime allows to study the low and the high energy ends of the particle…

Results of a 2000 August 12-13 BeppoSAX observation of the 7.1 hr eclipsing, dipping, bursting, transient, low-mass X-ray binary (LMXRB) X1658-298 are presented. The spectrum outside of eclipses, dips and bursts can be modeled by the…

The results of VLBI total intensity (I) and linear polarization (P) observations at 6cm are presented for ten radio bright BL Lacertae objects. These images complete first-epoch polarization observations for the 1-Jy sample of northern BL…

We put forward a scenario where blazars are classified as flat-spectrum radio quasars, BL Lacs, low synchrotron, or high synchrotron peaked objects according to a varying combination of Doppler boosted radiation from the jet, emission from…

In this work, we collected a sample of 69 TeV blazars from TeVCat, obtained their multi-wavelength observations, and fitted their spectral energy distributions by using the second degree polynomial function. The structure parameters of the…

We have observed 1ES 1426+428 with INTEGRAL detecting it up to $\sim$150 keV. The spectrum is hard, confirming that this source is an extreme BL Lac object, with a synchrotron component peaking, in a $\nu F_\nu$ plot, at or above 100 keV,…

We investigate quantitatively how the peak emission frequency of the overall energy spectrum is at work in distinguishing RBL-like and XBL-like objects. We employ the sample of Giommi et al. (1995) to study the distribution of BL Lacertae…

We present the broad band analysis of two BeppoSAX observations of the Sy 1 Mkn509. In 2000 the source was in a typical flux state, F{2-10keV}=2.7x10^{-11}erg cm^{-2} s^{-1}, while in 1998 it was found in a high flux state,…

Context. Blazar AO 0235+164, located at redshift z = 0.94, has undergone several sharp multi-spectral-range flaring episodes during the last decades. In particular, the episodes peaking in 2008 and 2015, that received extensive…

BL Lac objects can be extreme in two ways: with their synchrotron emission, peaking beyond 1 keV in their spectral energy distribution, or with their gamma-ray emission, peaking at multi-TeV energies up to and beyond 10-20 TeV, like 1ES…

We present a study of the intraday variability behaviour of two samples of x-ray selected BL Lac objects, the EMSS and EXOSAT samples consisting of 22 and 11 sources, respectively. In both samples we were able to detect intraday variability…

We present the first deep VLA radio images of flat-spectrum radio quasars (FSRQ) with multiwavelength emission properties similar to those of BL Lacs with synchrotron X-rays. Our observations of twenty-five of these sources show that their…

AIMS. We are studying an unbiased sample of 42 nearby (z < 0.2) BL Lacertae objects with a multi-wavelength approach. The results of VLBI observations were presented in the first paper of this series. In this paper, we study the…

At the end of March 2004, the blazar S5 0716+714 underwent an optical outburst that prompted for quasi-simultaneous target-of-opportunity observations with the INTEGRAL and XMM-Newton satellites. In this paper, we report the results of the…