Multiwavelength Spectral Analysis and Neural Network Classification of Counterparts to 4FGL Unassociated Sources. (arXiv:2110.04100v2 [astro-ph.HE] UPDATED)

Multiwavelength Spectral Analysis and Neural Network Classification of Counterparts to 4FGL Unassociated Sources. (arXiv:2110.04100v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Kerby_S/0/1/0/all/0/1">Stephen Kerby</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kaur_A/0/1/0/all/0/1">Amanpreet Kaur</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Falcone_A/0/1/0/all/0/1">Abraham D. Falcone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Eskenasy_R/0/1/0/all/0/1">Ryan Eskenasy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hancock_F/0/1/0/all/0/1">Fredric Hancock</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stroh_M/0/1/0/all/0/1">Michael C. Stroh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferrara_E/0/1/0/all/0/1">Elizabeth C. Ferrara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ray_P/0/1/0/all/0/1">Paul S. Ray</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kennea_J/0/1/0/all/0/1">Jamie A. Kennea</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grove_E/0/1/0/all/0/1">Eric Grove</a>

The Fermi-LAT unassociated sources represent some of the most enigmatic
gamma-ray sources in the sky. Observations with the Swift-XRT and -UVOT
telescopes have identified hundreds of likely X-ray and UV/optical counterparts
in the uncertainty ellipses of the unassociated sources. In this work we
present spectral fitting results for 205 possible X-ray/UV/optical counterparts
to 4FGL unassociated targets. Assuming that the unassociated sources contain
mostly pulsars and blazars, we develop a neural network classifier approach
that applies gamma-ray, X-ray, and UV/optical spectral parameters to yield
descriptive classification of unassociated spectra into pulsars and blazars.
From our primary sample of 174 Fermi sources with a single X-ray/UV/optical
counterpart, we present 132 P_bzr > 0.99 likely blazars and 14 P_bzr < 0.01
likely pulsars, with 28 remaining ambiguous. These subsets of the unassociated
sources suggest a systematic expansion to catalogs of gamma-ray pulsars and
blazars. Compared to previous classification approaches our neural network
classifier achieves significantly higher validation accuracy and returns more
bifurcated P_bzr values, suggesting that multiwavelength analysis is a valuable
tool for confident classification of Fermi unassociated sources.

The Fermi-LAT unassociated sources represent some of the most enigmatic
gamma-ray sources in the sky. Observations with the Swift-XRT and -UVOT
telescopes have identified hundreds of likely X-ray and UV/optical counterparts
in the uncertainty ellipses of the unassociated sources. In this work we
present spectral fitting results for 205 possible X-ray/UV/optical counterparts
to 4FGL unassociated targets. Assuming that the unassociated sources contain
mostly pulsars and blazars, we develop a neural network classifier approach
that applies gamma-ray, X-ray, and UV/optical spectral parameters to yield
descriptive classification of unassociated spectra into pulsars and blazars.
From our primary sample of 174 Fermi sources with a single X-ray/UV/optical
counterpart, we present 132 P_bzr > 0.99 likely blazars and 14 P_bzr < 0.01
likely pulsars, with 28 remaining ambiguous. These subsets of the unassociated
sources suggest a systematic expansion to catalogs of gamma-ray pulsars and
blazars. Compared to previous classification approaches our neural network
classifier achieves significantly higher validation accuracy and returns more
bifurcated P_bzr values, suggesting that multiwavelength analysis is a valuable
tool for confident classification of Fermi unassociated sources.

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