A staff of astronomers from Switzerland and Germany has performed a long-term multi-band photometric monitoring of a nearby blazar referred to as Markarian 501. The observational marketing campaign delivered important info concerning the blazar’s variability and detected quite a few flares from this supply. Outcomes of the research had been revealed September 7 on arXiv.org.
Blazars are very compact quasars related to supermassive black holes (SMBHs) on the facilities of energetic, large elliptical galaxies. They belong to a bigger group of energetic galaxies that host energetic galactic nuclei, and are probably the most quite a few extragalactic gamma-ray sources. Their attribute options are relativistic jets pointed nearly precisely towards the Earth.
BL Lacertae objects (BL Lacs) are a kind of blazar showcasing lower-power jets and better Doppler elements than different blazars. Primarily based on the situation of the synchrotron peak, they are often divided into low (LBLs), intermediate (IBLs), and excessive synchrotron peak BL Lacs (HBLs). Astronomers are particularly all in favour of discovering uncommon excessive HBLs (EHBLs)—recognized by synchrotron emission peaks at energies above 1 keV. Such objects are believed to be among the many most effective and excessive accelerators within the universe.
At a redshift of 0.034, Markarian 501 (or Mrk 501) is among the most ceaselessly studied nearby shiny blazars. Earlier observations of this supply have instructed that it might be an EHBL. A gaggle of researchers led by Axel Arbet-Engels of the Swiss Federal Institute of Know-how in Zürich, Switzerland, determined to additional examine this speculation by conducting a long-term multi-band photometry of Mrk 501 utilizing numerous ground-based services and house telescopes, together with the First G-APD Cherenkov Telescope (FACT).
“We studied the broadband variability of Mrk 501 from the top of 2012 to the center of 2018. Knowledge from eight devices had been thought-about,” the astronomers wrote within the paper.
The variability of Mrk 501 was detected in all wave bands. The fractional variability is lowest within the radio and highest within the TeV band, and it monotonically will increase from the radio to the X-rays and from the GeVs to the TeVs.
The lag between the TeV and X-ray variations had been estimated to be lower than 0.4 days. In keeping with the researchers, this nearly zero lag is in step with synchrotron self-Compton (SSC) emission, the place TeV photons are produced by inverse Compton scattering.
“The reported delay
The observations additionally recognized quite a few TeV and X-ray flares from Mrk 501. The attribute time interval between TeV flares was discovered to be comparable with the expectation if these flares are triggered by the so-called Lense-Thirring precession (a relativistic correction to the precession of a gyroscope close to a big rotating mass) of the accretion disk across the SMBH.
Axel Arbet-Engels et al, Lengthy-term multi-band photometric monitoring of Mrk 501. arXiv:2109.03205v1 [astro-ph.HE], arxiv.org/abs/2109.03205
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Astronomers monitor nearby blazar Markarian 501 (2021, September 14)
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