Related papers: Variability in Blazars: Clues from PKS 2155-304
We have examined 13 pointed observations of the TeV emitting high synchrotron peak blazar PKS 2155-304, taken by the Suzaku satellite throughout its operational period. We found that the blazar showed large-amplitude intraday variabilities…
TeV emission can be a common characteristic of low power blazars. This is in line with the sequence of blazars relating the observed bolometric luminosity with their overall spectral energy distribution. Detecting new TeV blazars, possibly…
The peak of the de-absorbed energy distribution of the TeV emitting BLs can reach values up to ~10 TeV. In the context of SSC models of relativistic uniformly moving blobs of plasma, such high energy peak emission can be reproduced only by…
Intense outbursts in blazars are among the most extreme phenomena seen in extragalactic objects. Studying these events can offer important information about the energetic physical processes taking place within the innermost regions of…
Recently, particle in cell (PIC) simulations have shown that relativistic turbulence in collisionless plasmas can result in an equilibrium particle distribution function where turbulent heating is balanced by radiative cooling of electrons.…
Context. The high-redshift (z = 4.72) blazar J1430+4204 produced a major radio outburst in 2005. Such outbursts are usually associated with the emergence of a new component in the inner radio jet. Aims. We searched for possible changes in…
A black hole can launch a powerful relativistic jet after it tidally disrupts a star. If this jet fortuitously aligns with our line of sight, the overall brightness is Doppler boosted by several orders of magnitude. Consequently, such…
Relativistic jets are thought to play a crucial role in the formation and evolution of massive galaxies and supermassive black holes. Blazars, which are quasars with jets aligned along our line of sight, provide insights into the jetted…
Through the modelling of the Spectral Energy Distribution of blazars we can infer the physical parameters required to originate the flux we see. Then we can estimate the power of blazar jets in the form of matter and fields. These estimates…
Blazar S5 0716+714 is well-known for its short-term variability, down to intra-day time-scales. We here present the 2-min cadence optical light curve obtained by the TESS space telescope in 2019 December - 2020 January and analyse the…
Very-high-energy $\gamma$-ray observations of the active galaxy IC 310 with the MAGIC telescopes have revealed fast variability with doubling time scales of less than 4.8min. This implies that the emission region in IC 310 is smaller than…
The extreme variability of blazars, in both timescale and amplitude, is generally explained as the effect of a relativistic jet closely aligned to the observer's line-of-sight. Due to causality arguments, variability characteristics…
The multi-wavelength spectrum observed from M87 extends from radio wavelengths up to TeV gamma-ray energies. The radio through GeV components have been interpreted successfully using SSC models based on misaligned blazar jets, but the…
The Fermi and Swift satellites, together with ground based Cherenkov telescopes, has greatly improved our knowledge of blazars, namely Flat Spectrum Radio Quasars and BL Lac objects, since all but the most powerful emit most of their…
Kinematical and luminosity relations for black-hole jet sources are reviewed. If the TeV flares observed from PKS 2155-304 in 2006 July are assumed to originate from a black hole with mass $\approx 10^8 M_8 M_\odot$, then the $\sim 5$…
High-redshift blazars are one of the most powerful monsters in the universe and $\gamma$-ray variability carries crucial information of their relativistic jets. In this work we present results of the first systematical temporal analysis of…
We present 88 multi-epoch Very Long Baseline Array (VLBA) images (most at an observing frequency of 8 GHz), of 20 TeV blazars, all of the HBL class, that have not been previously studied at multiple epochs on the parsec scale. From these 20…
We present optical light curves for the period 1996-2000, of two of the brightest known EGRET BL Lac objects: PKS 2005-489 and PKS 2155-304, the latter also one of the few known TeV sources. For both objects, quiescent epochs of low level…
PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying…
The bright X-ray selected BL Lacertae object PKS 2155-304 has been the target of two intense multiwavelength campaigns, in November 1991 and in May 1994. Although the spectral energy distributions at both epochs were quite similar, the…