Extended TeV Halos May Commonly Exist around Middle-Aged Pulsars
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Albert, A. (ORCID:0000000301975646)↗
Engineering topics
Dingus, B. L. (ORCID:0000000184517450)
Publications and source records attributed to Dingus, B. L. (ORCID:0000000184517450).
Searching for TeV Dark Matter in Irregular Dwarf Galaxies with HAWC Observatory
We present the results of dark matter (DM) searches in a sample of 31 dwarf irregular (dIrr) galaxies within the field of view of the HAWC Observatory. dIrr galaxies are DM-dominated objects in which astrophysical gamma-ray emission is estimated to be negligible with respect to the secondary gamma-ray flux expected by annihilation or decay of weakly interacting massive particles (WIMPs). While we do not see any statistically significant DM signal in dIrr galaxies, we present the exclusion limits (95% C.L.) for annihilation cross section and decay lifetime for WIMP candidates with masses between 1 and 100 TeV. Exclusion limits from dIrr galaxies are relevant and complementary to benchmark dwarf Spheroidal (dSph) galaxies. In fact, dIrr galaxies are targets kinematically different from benchmark dSph, preserving the footprints of different evolution histories. We compare the limits from dIrr galaxies to those from ultrafaint and classical dSph galaxies previously observed with HAWC. We find that the constraints are comparable to the limits from classical dSph galaxies and ~2 orders of magnitude weaker than the ultrafaint dSph limits.
79 ASTRONOMY AND ASTROPHYSICS↗
γ-Ray Emission from Classical Nova V392 Per: Measurements from Fermi and HAWC
This paper reports on the γ -ray properties of the 2018 Galactic nova V392 Per, spanning photon energies ~0.1 GeV–100 TeV by combining observations from the Fermi Gamma-ray Space Telescope and the HAWC Observatory. As one of the most rapidly evolving γ -ray signals yet observed for a nova, GeV γ -rays with a power-law spectrum with an index Γ = 2.0 ± 0.1 were detected over 8 days following V392 Per’s optical maximum. HAWC observations constrain the TeV γ -ray signal during this time and also before and after. We observe no statistically significant evidence of TeV γ -ray emission from V392 Per, but present flux limits. Tests disfavor the extension of the Fermi Large Area Telescope spectrum to energies above 5 TeV by 2 standard deviations (95%) or more. We fit V392 Per’s GeV γ -rays with hadronic acceleration models, incorporating optical observations, and compare the calculations with HAWC limits.
79 ASTRONOMY AND ASTROPHYSICS↗
Multimessenger Gamma-Ray and Neutrino Coincidence Alerts Using HAWC and IceCube Subthreshold Data
The High Altitude Water Cerenkov (HAWC) and IceCube observatories, through the Astrophysical Multimessenger Observatory Network (AMON) framework, have developed a multimessenger joint search for extragalactic astrophysical sources. This analysis looks for sources that emit both cosmic neutrinos and gamma rays that are produced in photohadronic or hadronic interactions. The AMON system is running continuously, receiving subthreshold data (i.e., data that are not suited on their own to do astrophysical searches) from HAWC and IceCube, and combining them in real time. Here we present the analysis algorithm, as well as results from archival data collected between 2015 June and 2018 August, with a total live time of 3.0 yr. During this period we found two coincident events that have a false-alarm rate (FAR) of <1 coincidence yr -1 , consistent with the background expectations. The real-time implementation of the analysis in the AMON system began on 2019 November 20 and issues alerts to the community through the Gamma-ray Coordinates Network with an FAR threshold of <4 coincidences yr -1 .
79 ASTRONOMY AND ASTROPHYSICS↗