Results 31 to 40 of about 272 (130)
Advances in Astronomy, Volume 2012, Issue 1, 2012., 2012 Recent polarimetric surveys of extragalactic radio sources (ERS) at frequencies ν ≳ 1 GHz are reviewed. By exploiting all the most relevant data we study the frequency dependence of polarization properties of ERS between 1.4 and 86 GHz. For flat‐spectrum sources the median (mean) fractional polarization increases from 1.5% (2–2.5%) at 1.4 GHz to 2.5–3%
Marco Tucci +2 more
wiley +1 more source
Imaging Redshifts of BL Lacertae Objects [PDF]
The Astrophysical Journal, 2005 The HST snapshot imaging survey of 110 BL Lac objects (Urry et al.) has clearly shown that the host galaxies are massive and luminous ellipticals. The dispersion of the absolute magnitudes is sufficiently small that the measurement of the galaxy brightness becomes a valuable way of estimating their distance. This is illustrated by constructing a Hubble
SBARUFATTI B, TREVES, ALDO, FALOMO R.
openaire +2 more sources
New Observations of BL Lacertae Objects [PDF]
Symposium - International Astronomical Union, 1996 This contribution is divided into three parts: 1. A summary of mostly published work that describes the new type of BL Lac Objects discovered with X-ray satellites, “X-ray Bright BL Lacs (XBLs)”, and their relationship to the previously known “radio bright BL Lacs (RBLs).” Most (but not all?) of the differences between XBLs and RBLs are explicable ...
Mei, D. C. +3 more
openaire +4 more sources
A Tentative Sketch for BL Lacertae Objects [PDF]
Symposium - International Astronomical Union, 1994 VLBI polarization data show magnetic field configuration parallel to the nuclear jet in quasars and perpendicular to it in BL Lac objects. It appears difficult to account for this contrast within the unified scheme for AGN. To investigate a direct explanation of this peculiarity of BL Lac objects, we study the possibilities of propagation and radiation
Hélène Sol, Lourdes Vicente
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Research of blazars at the Astronomical observatory of Belgrade [PDF]
Serbian Astronomical Journal, 2014 At the beginning of 2013, we have a team of scientists at the Astronomical Observatory of Belgrade, focusing on observations and research of blazars.
Vince O., Damljanović G.
doaj +1 more source
Sub-Hour X-Ray Variability of High-Energy Peaked BL Lacertae Objects
Galaxies, 2018 The study of multi-wavelength flux variability in BL Lacertae objects is very important to discern unstable processes and emission mechanisms underlying their extreme observational features. While the innermost regions of these objects are not accessible
Bidzina Kapanadze
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Statistical Analysis of the Microvariable AGN Source Mrk 501
Galaxies, 2018 We report on the optical observations and analysis of the high-energy peaked BL Lac object (HBL), Mrk 501, at redshift z = 0.033. We can confirm microvariable behavior over the course of minutes on several occasions per night.
Alberto C. Sadun +3 more
doaj +1 more source
Investigating the Puzzling Synchrotron Behaviour of Mrk 421
Galaxies, 2016 We investigate the multiwavelength behaviour of the high-energy peaked BL Lac object (HBL) Mrk 421 at redshift z = 0 . 031 in the period 2007–2015.
Maria I. Carnerero +6 more
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The First- and Second-Order Fermi Acceleration Processes in BL Lacertae Objects
Galaxies, 2018 BL Lacertae objects constitute a rare class of active galactic nuclei with extreme observational features attributed to the Doppler-boosted emission from a relativistic jet, closely aligned to our line-of-sight.
Bidzina Kapanadze
doaj +1 more source
The “Blazar Sequence” in the TeV Band
The Astrophysical Journal, 2023 The “blazar sequence” has been proposed for more than 20 yr, yet its nature is still unclear. In this work, for the first time we expand this topic to the TeV band by using a sample of 58 TeV blazars, including 48 blazars in the quiescent state and 21 ...
Zhihao Ouyang +9 more
doaj +1 more source