Related papers: Testing the blazar sequence with the least luminou…
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…
We aim to test if a blazar candidate of uncertain-type (BCU) in the third Fermi active galactic nuclei catalog (3LAC) can be potentially classified as a BL Lac object or a flat spectrum radio quasar (FSRQ) by performing a statistical…
We present a study of high-cadence, high-precision, optical light curves from the TESS satellite of 67 blazars in the southern sky. We provide descriptive flux statistics, power spectral density model parameters, and characteristic…
We estimate the stellar mass for a sample of low surface brightness galaxies (LSBGs) by fitting their multiband spectral energy distributions (SEDs) to the stellar population synthesis (SPS) model. The derived stellar masses (log M*/Msun)…
The long-term optical and infrared color variability of blazars has been investigated with the SMARTS monitoring data. The sample in this study consists of 49 flat spectrum radio quasars and 22 BL Lac objects. The fractional variability…
Using public \fermi LAT and \swift BAT observations, we constructed the first sample of blazars selected at both hard X-rays and gamma-rays. Studying its spectral properties, we find a luminosity dependence of the spectral slopes at both…
BL Lac objects are the best candidates to study the jet properties since their spectral energy distributions (SEDs) are less contaminated by the emission from the accretion disk and external Compton processes. We compile the broadband SEDs…
With its very wide energy band (0.1-100 keV), BeppoSAX has played a fundamental role in the blazar field, allowing in particular a better study of the highest synchrotron peaked objects. Here we summarize the results of an observational…
We report radio imaging and monitoring observations in the frequency range 0.235 - 2.7 GHz during the flaring mode of PKS 2155-304, one of the brightest BL Lac objects. The high sensitivity GMRT observations not only reveal extended…
We report the variation of the spectral energy distribution (SED) of blazars as a function of source activity, based on available, simultaneous multi-wavelength (MWL) observations of BL Lac objects. We use a fully automatized \c{hi}2…
We have used all 20 archival XMM-Newton observations of PKS 2155-304 with simultaneous X-ray and UV/optical data to study its long term flux and spectral variability. We find significant variations, in all bands, on time-scales of years…
We present a radio/optical study of a sample of BL Lac objects at arcsecond and milliarcsecond resolution. The sample consists of 30 nearby (z<0.2) BL Lacs, mostly X-ray selected. These nearby objects are weak in the radio, yet we have…
We present the results of the BeppoSAX observations of two BL Lacs, OQ 530 and S5 0716+714, as part of a ToO program for the simultaneous observation at radio, optical, X-ray and TeV energies. Both sources are detected in the LECS and MECS,…
We present recent ROSAT, ASCA and SAX observations of intermediate BL Lac objects (IBLs), i.e. BL Lacs which are located between high-energy and low-energy peaked BL Lac objects with respect to alpha_rx. Both the statistical properties of…
We present a morphological and spectral study of a sample of 99 BL Lacs using the LOFAR Two-Metre Sky Survey Second Data Release (LDR2). Extended emission has been identified at gigahertz frequencies around BL Lacs, but with LDR2 it is now…
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…
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…
Blazars are among the most studied sources in high-energy astrophysics as they form the largest fraction of extragalactic gamma-ray sources and are considered prime candidates for being the counterparts of high-energy astrophysical…
(Abridged) We report on the X-ray and multiwavelength properties of 11 radio-quiet quasars with weak or no emission lines identified by the Sloan Digital Sky Survey (SDSS) with redshift z=0.4-2.5. The distribution of relative X-ray…
We present the results of EVN and MERLIN 5 GHz observations of nine ultra-high-energy synchrotron peak BL Lacs (UHBLs) selected as all BL Lacs with \textbf{log ($\nu_{\rm peak}/ \rm Hz)>20$} from Nieppola et al.. The radio structure was…