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Further Fermi-LAT Gamma-ray Observations of Nova Sagittarii 2015 No. 2

ATel #7315; C. C. Cheung (NRL), P. Jean (IRAP, Toulouse), on behalf of the Fermi Large Area Telescope Collaboration, S. N. Shore (U. Pisa and INFN)
on 30 Mar 2015; 18:06 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Teddy Cheung (ccheung@milkyway.gsfc.nasa.gov)

Subjects: Gamma Ray, >GeV, Nova, Transient

Referred to by ATel #: 7744, 8133, 10557

Following the initial Fermi-LAT report of evidence for >100 MeV emission from Nova Sgr 2015 No. 2 at 3.8-sigma significance from March 23.00-24.24 (ATEL #7283), preliminary analysis indicates the nova was detected again in gamma rays from March 26.0-28.0 at 4.0 sigma. The new detection coincides with optical rebrightening seen in the prevalidated AAVSO light curve, with a 2-day average flux, F(E>100 MeV) = (1.4 +/- 0.5) x 10^-7 ph cm^-2 s^-1 (assuming a single power-law with photon index = 2.2 fixed), that is consistent with the March 23.00-24.24 flux.

We strongly encourage multiwavelength observations. The Fermi ToO observation of Nova Sgr 2015 No. 2 has been extended to the end of April 4th. For this source the Fermi LAT contact person is C.C. Cheung (Teddy.Cheung@nrl.navy.mil).

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.