Fermi-LAT Detection of Galactic Nova V8056 Sgr

ATel #18122; Peter Craig, Laura Chomiuk (MSU), Elias Aydi (TTU), Kirill Sokolovsky, Justin Linford (NRAO), Koji Mukai (NASA/GSFC), Jennifer Sokoloski (Columbia)
on 28 Oct 2026; 21:03 UT
Credential Certification: Peter Craig (pac4607@rit.edu)

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Following the discovery of V8056 Sgr (TCP J17541876-2736362) on 2026 October 12, and its associated spectroscopic classification as a nova (CBET #5763), we have been monitoring the public Fermi-LAT data to search for GeV gamma-ray emission from this nova.

We report the detection of GeV gamma-ray emission consistent with the position of this nova, with a test statistic of 52, based on a binned likelihood analysis of Fermi-LAT data in the 100 MeV–300 GeV range. This preliminary analysis includes LAT data from 2026 October 16 at 00:00:00 UTC through 2026 October 23 at 00:00:00 UTC; significant detections are achieved in a range of similar time windows. A light curve with 2 day windows shows a rise in significance on 2026 October 18.

The nova is modeled with a power law with the photon index free to vary, with a best fit identified as 1.99 ± 0.15, a typical photon index for a nova (Franckowiak et al. 2018). The resulting detection corresponds to a significance of approximately 7 sigma. The integrated photon flux in this 100 MeV–300 GeV band is (4.4 ± 1.6) × 10^-7 ph cm^-2 s^-1 (statistical uncertainties only). The best-fit position, RA = 268.613, Dec = −27.616 (error radius 0.047°), is 0.03° from the optical position of the nova.

We encourage continued multi-wavelength observations of this nova during the ongoing outburst.