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Title: Six-year optical monitoring of the BL Lacertae object 1ES 0806+52.4

We present the results of the first systematic long-term multicolor optical monitoring of the BL Lacertae object 1ES 0806+52.4. The monitoring was performed in multiple passbands with a 60/90 cm Schmidt telescope from 2005 December to 2011 February. The overall brightness of this object decreased from 2005 December to 2008 December but was regained after that. A sharp outburst probably occurred around the end of our monitoring program. Overlapping the long-term trend are some short-term small-amplitude oscillations. No intranight variability was found in the object, which is in accordance with the historical observations before 2005. By investigating the color behavior, we found a strong bluer-when-brighter chromatism for the long-term variability of 1ES 0806+52.4. The total amplitudes at the c, i, and o bands are 1.18, 1.12, and 1.02 mag, respectively. The amplitudes tend to increase toward shorter wavelengths, which may be a major cause of the bluer-when-brighter chromatism. Such bluer-when-brighter chromatisms are also found in other blazars, such as S5 0716+714, OJ 287. The hard-X-ray data collected from the Swift/BAT archive was correlated with our optical data. No positive result was found, the reason for which may be that the hard-X-ray flux is a combination of the synchrotron and inversemore » Compton emission, but with different timescales and cadences under the leptonic synchrotron self-Compton model.« less
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Astronomy, Beijing Normal University, Beijing 100875 (China)
  2. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Beijing 100012 (China)
  3. Department of Physics and Institute of Theoretical Physics, Nanjing Normal University, Nanjing 210046 (China)
Publication Date:
OSTI Identifier:
22342186
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 6; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; BL LACERTAE OBJECTS; BRIGHTNESS; COLOR; COMPTON EFFECT; EMISSION; GALAXIES; HARD X RADIATION; PHOTOMETRY; TELESCOPES; VISIBLE RADIATION; WAVELENGTHS