Search for High-Energy Neutrinos from Ultra-Luminous Infrared Galaxies with IceCube

Abstract

Ultra-luminous infrared galaxies (ULIRGs) have infrared luminosities $L_{\mathrm{IR}}\ge 10^{12}{L}_{\odot }$, making them the most luminous objects in the infrared sky. These dusty objects are generally powered by starbursts with star-formation rates that exceed $100M_{\odot }{\mathrm{yr}}^{-1}$, possibly combined with a contribution from an active galactic nucleus. Such environments make ULIRGs plausible sources of astrophysical high-energy neutrinos, which can be observed by the IceCube Neutrino Observatory at the South Pole. We present a stacking search for high-energy neutrinos from a representative sample of 75 ULIRGs with redshift $z\le 0.13$ using 7.5 years of IceCube data. The results are consistent with a background-only observation, yielding upper limits on the neutrino flux from these 75 ULIRGs. For an unbroken $E^{-2.5}$ power-law spectrum, we report an upper limit on the stacked flux $\hat{I}{¦}_{\hat{I}{½}_{\hat{I}}¼+\bar{\hat{I}}{½}_{\hat{I}}¼}^{90\%}=3.24\times 10^{-14}\mathrm{Te}{\mathrm{V}}^{-1}\mathrm{c}{\mathrm{m}}^{-2}{\mathrm{s}}^{-1}(E/10\mathrm{TeV}{)}^{-2.5}$ at 90% confidence level. In addition, we constrain the contribution of the ULIRG source population to the observed diffuse astrophysical neutrino flux as well as model predictions.

Accepted for publication in ApJ. 18 pages, 5 figures, 3 tables