First Bounds on the Very High Energy γ‐Ray Emission from Arp 220

Abstract

Using the Major Atmospheric Gamma Imaging Cerenkov Telescope (MAGIC), we have observed the nearest ultraluminous infrared galaxy, Arp 220, for about 15 hr. No significant signal was detected within the dedicated amount of observation time. The first upper limits to the very high energy γ-ray flux of Arp 220 are herein reported and compared with theoretical expectations.