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Gamma-ray Novae: Rare or Nearby?

Morris, P.J.; Cotter, G.; Brown, A.M.; Chadwick, P.M.

Gamma-ray Novae: Rare or Nearby? Thumbnail


P.J. Morris

G. Cotter


Classical novae were revealed as a surprise source of γ-rays in Fermi Large Area Telescope (LAT) observations. During the first 8 yr since the LAT was launched, 6 novae in total have been detected to >5σ in γ-rays, in contrast to the 69 discovered optically in the same period. We attempt to resolve this discrepancy by assuming all novae are γ-ray emitters, and assigning peak 1 d fluxes based on a flat distribution of the known emitters to a simulated population. To determine optical parameters, the spatial distribution and magnitudes of bulge and disc novae in M31 are scaled to the Milky Way, which we approximate as a disc with a 20 kpc radius and elliptical bulge with semimajor axis 3 kpc and axis ratios 2:1 in the xy plane. We approximate Galactic reddening using a double exponential disc with vertical and radial scaleheights of rd = 5 kpc and zd = 0.2 kpc, and demonstrate that even such a rudimentary model can easily reproduce the observed fraction of γ-ray novae, implying that these apparently rare sources are in fact nearby and not intrinsically rare. We conclude that classical novae with mR ≤ 12 and within ≈ 8 kpc are likely to be discovered in γ-rays using the Fermi LAT.


Morris, P., Cotter, G., Brown, A., & Chadwick, P. (2017). Gamma-ray Novae: Rare or Nearby?. Monthly Notices of the Royal Astronomical Society, 465(1), 1218-1226.

Journal Article Type Article
Acceptance Date Feb 20, 2017
Online Publication Date Oct 27, 2016
Publication Date Feb 11, 2017
Deposit Date Feb 20, 2017
Publicly Available Date Feb 21, 2017
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 465
Issue 1
Pages 1218-1226
Related Public URLs


Published Journal Article (1.5 Mb)

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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