1999/08/06 by E. Bertone, Bertone, E., G. Tagliaferri +9
Engineering · Physics and Astronomy · #Astrophysics (astro-ph) #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Particle Accelerators and Free-Electron Lasers #Particle accelerators and beam dynamics #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9908069
2 pages, 4 figures, contributed paper at the OJ-94 annual meeting, Torino, Italy, May 19-21, 1999
arxiv created 1999/08/06 · openalex publication_date 1999/08/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Infrared Space Observatory (ISO) observed the BL Lac object PKS 2155-304 16 times from 1996, May 7 to June 8, with both the ISOCAM camera and the ISOPHOT photometer, as part of a more general multiwavelength campaign. Two additional observations were performed on 1996, November 23 and 1997, May 15. This is the first time that there are simultaneous mid and far infrared data in a multiwavelength monitoring of a BL Lac object. We obtained four light curves at 4.0, 14.3, 60 and 90 microns, and a broad-band filter spectrum from 2.8 to 170 micron. No variability was detected in the infrared, although the source was varying at shorter wavelengths. The IR spectrum can be fitted by a single power law with an energy spectral index alfa = 0.40 +/- 0.06 and it can be explained as due to synchrotron emission only, with no noticeable contributions from thermal sources. Using the simultaneous data, we constructed the SED of PKS 2155-304.