Research Note
Constraining extragalactic background light from TeV blazars
1
National Astronomical Observatories, Yunnan Observatory, Chinese Academy of
Sciences
Kunming
650011
PR China
e-mail: yangjp@ynao.ac.cn
2
Key Laboratory for the Structure and Evolution of Celestial
Objects, Chinese Academy of Sciences, Kunming
650011, PR
China
3
Yunnan Agricultural University, Kunming
650201, PR
China
Received:
2
April
2010
Accepted:
17
June
2010
Aims. Our goal is to research the upper limits to the extragalactic background light (EBL).
Methods. The upper limits to the extragalactic background light (EBL) are presented, using the Fermi and very high energy (VHE) spectra recently observed in TeV blazars. We use an assumption that the VHE intrinsic photon index cannot be harder than the Fermi index measured by the Fermi-LAT.
Results. These upper limits are compatible with ones given by most EBL models; however, the models of high EBL density are contradicted by TeV blazars.
Key words: gamma rays: galaxies / BL Lacertae objects: general / diffuse radiation
© ESO, 2010