[ Previous | Next ]
ATEL # 2293; W. Hofmann (MPIK) on behalf of the H.E.S.S. collaboration, S. Fegan (LLR) on behalf of the Fermi-LAT collaboration
on 12 Nov 2009; 16:38 UT
Password Certification: Michael Punch (firstname.lastname@example.org)
Subjects: Gamma Ray, >GeV, Request for Observations, AGN
The H.E.S.S. and Fermi collaborations report the discovery of very-high energy (VHE; E>100 GeV) and high-energy (HE; E>1GeV) gamma-ray emission from the high energy peaked BL Lac object 1ES 0414+009 (RA: 04h16m52.41s, DEC: +01d05m24.3s, J2000) located at a redshift of z=0.287 (Sbarufatti et al., ApJ, 635:173-179, 2005), one of the furthest VHE blazars with a well-determined redshift today. The VHE emission of this source has been detected in a 60h data-set of good-quality observations taken between October 3, 2005 and September 28, 2009, with the H.E.S.S. imaging atmospheric Cherenkov telescope array. The analysis of this data-set using two independent recently-published advanced analysis methods result in an an excess of ~195 gamma-rays at >5 standard deviations (corresponding to ~0.5% Crab flux level) coming from a position consistent with that of 1ES~0414+009 (within the position errors of 0.05 degrees). The LAT detected HE gamma rays from a source positionally consistent with 1ES 0414+009 with a statistical significance of ~7 standard deviations. Preliminary analysis of the LAT data taken during the first 12.5 months of the science phase of the mission (August 4, 2008 to August 25, 2009) indicates an average flux above 1 GeV of (0.67 ± 0.21) x 10-9 photons cm-2 s-1, and a hard spectral index of (1.78 ± 0.23). Errors are statistical only. An extrapolation of this Fermi spectrum gives a 0.7% Crab flux estimate above the H.E.S.S. energy threshold. H.E.S.S. is an array of four imaging atmospheric Cherenkov telescopes located in the Khomas highlands in Namibia, for the detection of gamma-ray sources above 100 GeV. It was constructed and is operated by researchers from Germany, France, UK, South Africa, Poland, the Czech and Irish republics, Armenia, Austria, Sweden, Australia, and the host country, Namibia. The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan, and Sweden. Further measurements of 1ES 0414+009 at these and other wavelengths are encouraged. For H.E.S.S. observations, the AGN coordinator is M. Punch (email@example.com) and the Multiwavelength coordinator Stefan Wagner (S.Wagner@lsw.uni-heidelberg.de). The LAT contact person for this blazar is S. Fegan (firstname.lastname@example.org).