2009A&A...503..797G


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST20:04:50

2009A&A...503..797G - Astronomy and Astrophysics, volume 503, 797-799 (2009/9-1)

Lognormal variability in BL Lacertae.

GIEBELS B. and DEGRANGE B.

Abstract (from CDS):

The characterization of a time series is a powerful tool for investigating the nature of mechanisms that generate variability in astrophysical objects. Blazar variability across the entire electromagnetic spectrum is a long-standing puzzle, and it has been difficult to ascertain the mechanisms at play. Lognormal variability in X-ray light curves, probably related to accretion disk activity, has been discovered in various compact systems, such as Seyfert galaxies and X-ray binaries. Identifying a similar behaviour in blazars would establish a link between them. Public X-ray data from the blazar BL Lac are used to investigate the nature of its variability, and more precisely the flux dependency of the variability and the distribution of fluxes. The variations in the flux are found to have a lognormal distribution and the average amplitude of variability is proportional to the flux level. BL Lac is the first blazar in which lognormal X-ray variability is clearly detected. The light curve is orders of magnitude less variable than other blazars, with few bursting episodes. If this defines a specific state of the source, then the lognormality might be the imprint of the accretion disk on the jet, linking for the first time accretion and jet properties in a blazar.

Abstract Copyright:

Journal keyword(s): X-rays: galaxies - galaxies: active - galaxies: BL Lacertae objects: individual: BL Lac - radiation mechanisms: non-thermal

CDS comments: Paragraph.3 IRAS 13244-3809 is a misprint for IRAS 13224-3809.

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 4253 Sy1 12 18 26.5155239433 +29 48 46.518670434   14.34 13.57     ~ 930 1
2 2MASX J13251937-3824524 Sy1 13 25 19.3805503234 -38 24 52.611897329   16.64 13.80 15.33   ~ 338 0
3 V* V4580 Sgr LXB 18 08 27.54 -36 58 44.3   16.81 16.51     ~ 870 0
4 HD 226868 HXB 19 58 21.6758193269 +35 12 05.782512305 9.38 9.72 8.91 8.42   O9.7Iabpvar 3923 0
5 QSO B2155-304 BLL 21 58 52.0651817803 -30 13 32.120657891   13.36 13.09 12.62   ~ 1560 1
6 NAME BL Lac BLL 22 02 43.2913773726 +42 16 39.978417860   15.66 14.72     ~ 2006 1

    Equat.    Gal    SGal    Ecl

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2020.07.04-20:04:50

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