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Detection of gamma rays from Nova Delphini 2013

ATel #5302; E. Hays (NASA/GSFC), T. Cheung (NRL), and S. Ciprini (ASI ASDC & INAF OAR Rome) on behalf of the Fermi Large Area Telescope Collaboration
on 20 Aug 2013; 18:22 UT
Credential Certification: Elizabeth Hays (elizabeth.a.hays@nasa.gov)

Subjects: Gamma Ray, >GeV, Nova, Transient

Referred to by ATel #: 5305, 5342, 5470, 5649, 7283, 7744

The Fermi Large Area Telescope left standard sky survey observations to observe Nova Delphini 2013 (CBET #3628) as a Target of Opportunity on 2013 August 16 at 14:09 UT. The nova reached a maximum optical brightness at 4.3 mag around August 16.5 UT referencing the AAVSO (see also ATEL #5297). In a preliminary daily analysis of the gamma-ray data, a signal at the location of the nova first appeared at >5 sigma significance for the day 2013 August 18.

The preliminary gamma-ray daily-averaged flux, F(E>100 MeV) = (3.3 +/- 0.8) x 10^-07 ph cm^-2 s^-1, and photon index, 2.2 +/- 0.2 (errors are statistical only), for August 18 are consistent with previous gamma-ray novae (ATels #2487, #4284, #4310).

The Fermi observations targeting Nova Delphini 2013 will continue at least until August 22 and, as always, this region will have regular gamma-ray monitoring after the return to Fermi's all-sky survey pattern. We strongly encourage multiwavelength observations. For this source the Fermi LAT contact persons are C.C. Cheung (Teddy.Cheung.ctr@nrl.navy.mil) and E. Hays (elizabeth.a.hays@nasa.gov).

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.