Spurious Point Source Signals in the Galactic Center Excess. (arXiv:2002.12370v2 [astro-ph.HE] UPDATED)

Spurious Point Source Signals in the Galactic Center Excess. (arXiv:2002.12370v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Leane_R/0/1/0/all/0/1">Rebecca K. Leane</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Slatyer_T/0/1/0/all/0/1">Tracy R. Slatyer</a>

We re-examine evidence that the Galactic Center Excess (GCE) originates
primarily from point sources (PSs). We show that in our region of interest,
non-Poissonian template fitting (NPTF) evidence for GCE PSs is an artifact of
unmodeled north-south asymmetry of the GCE. This asymmetry is strongly favored
by the fit (although it is unclear if this is physical), and when it is
allowed, the preference for PSs becomes insignificant. We reproduce this
behavior in simulations, including detailed properties of the spurious PS
population. We conclude that NTPF evidence for GCE PSs is highly susceptible to
certain systematic errors, and should not at present be taken to robustly
disfavor a dominantly smooth GCE.

We re-examine evidence that the Galactic Center Excess (GCE) originates
primarily from point sources (PSs). We show that in our region of interest,
non-Poissonian template fitting (NPTF) evidence for GCE PSs is an artifact of
unmodeled north-south asymmetry of the GCE. This asymmetry is strongly favored
by the fit (although it is unclear if this is physical), and when it is
allowed, the preference for PSs becomes insignificant. We reproduce this
behavior in simulations, including detailed properties of the spurious PS
population. We conclude that NTPF evidence for GCE PSs is highly susceptible to
certain systematic errors, and should not at present be taken to robustly
disfavor a dominantly smooth GCE.

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