New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200

Details New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200 New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200

2007-09-28

arxiv.org/abs/0709.4584v1

A&A, 475, L9, 2007

Astronomy and Astrophysics

Astrophysics

5 pages, 4 figures; Accepted for publication in A&A Letters on September 23, 2007

Scientific paper

10.1051/0004-6361:20078462

AIMS: To investigate the very high energy (VHE: >100 GeV) gamma-ray emission from the high-frequency peaked BL Lac 1ES 0229+200. METHODS: Observations of 1ES 0229+200 at energies above 580 GeV were performed with the High Energy Stereoscopic System (HESS) in 2005 and 2006. RESULTS: 1ES 0229+200 is discovered by HESS to be an emitter of VHE photons. A signal is detected at the 6.6 sigma level in the HESS observations (41.8 h live time). The integral flux above 580 GeV is (9.4 +- 1.5 {stat} +- 1.9 {syst}) x 10^{-13} cm^{-2} s^{-1}, corresponding to ~1.8% of the flux observed from the Crab Nebula. The data show no evidence for significant variability on any time scale. The observed spectrum is characterized by a hard power law (Gamma = 2.50 +- 0.19 {stat} +- 0.10 {syst}) from 500 GeV to ~15 TeV. CONCLUSIONS: The high-energy range and hardness of the observed spectrum, coupled with the object's relatively large redshift (z=0.1396), enable the strongest constraints so far on the density of the Extragalactic Background Light (EBL) in the mid-infrared band. Assuming that the emitted spectrum is not harder than Gamma_{int} ~ 1.5, the HESS data support an EBL spectrum ~ lambda^{-1} and density close to the lower limit from source counts measured by Spitzer, confirming the previous indications from the HEGRA data of 1ES 1426+428 (z=0.129). Irrespective of the EBL models used, the intrinsic spectrum of 1ES 0229+200 is hard, thus locating the high-energy peak of its spectral energy distribution above a few TeV.

Affiliated with

Also associated with

No associations

Rating

New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-715033