2016A&A...591A..83S


Query : 2016A&A...591A..83S

2016A&A...591A..83S - Astronomy and Astrophysics, volume 591A, 83-83 (2016/7-1)

Long-term study of Mkn 421 with the HAGAR Array of Telescopes.

SINHA A., SHUKLA A., SAHA L., ACHARYA B.S., ANUPAMA G.C., BHATTACHARJEE P., BRITTO R.J., CHITNIS V.R., PRABHU T.P., SINGH B.B. and VISHWANATH P.R.

Abstract (from CDS):

Context. The HAGAR Telescope Array at Hanle, Ladakh has been regularly monitoring the nearby blazar Mkn 421 for the past seven years.
Aims. Blazars show flux variability in all timescales across the electromagnetic spectrum. While there is abundant literature characterizing the short-term flares from different blazars, comparatively little work has been carried out to study the long-term variability. We aim to study the long-term temporal and spectral variability in the radiation from Mkn 421 during 2009-2015.
Methods. We quantify the variability and lognormality from the radio to very high-energy (VHE) bands, and compute the correlations between various wavebands using the z-transformed discrete correlation function. We construct the spectral energy distribution (SED) contemporaneous with HAGAR observation seasons and fit this SED with a one-zone synchrotron self-Compton model to study the spectral variability.
Results. The flux is found to be highly variable across all timescales. The variability is energy dependant and is maximum in the X-ray and VHE bands. A strong correlation is found between the Fermi-LAT (gamma) and radio bands and between Fermi-LAT and optical, but no correlation is found between Fermi-LAT and X-ray. Lognormality in the flux distribution is clearly detected. This is the third blazar, following BL Lac and PKS 2155+304 to show this behaviour. The SED can be well fit by a one-zone SSC model, and variations in the flux states can be attributed mainly to changes in the particle distribution. A strong correlation is seen between the break energy γb of the particle spectrum and the total bolometric luminosity.

Abstract Copyright: © ESO, 2016

Journal keyword(s): radiation mechanisms: non-thermal - gamma rays: galaxies - BL Lacertae objects: individual: Mkn 421 - galaxies: active

CDS comments: PKS 2155+304 is a misprint for PKS 2155-304.

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 M 1 SNR 05 34 32 +22 00.8           ~ 5973 1
2 Mrk 421 BLL 11 04 27.3140835504 +38 12 31.798495872   13.50 12.90 8.31   ~ 2550 1
3 NGC 4253 Sy1 12 18 26.5163572920 +29 48 46.531535472   14.34 13.57     ~ 999 1
4 QSO B2155-304 BLL 21 58 52.0652249880 -30 13 32.118447792   13.36 13.09 12.62   ~ 1661 1
5 NAME BL Lac BLL 22 02 43.2913536816 +42 16 39.979416792   15.66 14.72     ~ 2156 1

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2022.11.28-13:03:53

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