Ultraluminous Extragalactic Chemistry

Abstract

AbstractAt a distance of 77 Mpc, the Ultralumious galaxy Arp 220 is the closest extragalactic equivalent to Galactic hot cores. The low resolution SMA survey showed a highly excited confusion limited spectrum. The new ALMA snapshot spectral scan opens the possibility of chemically resolve the two nuclei at unprecedented sensitivity. When completed, it will be the widest survey ever done towards an extragalactic object. The model of Band 6 and 7 data already shows the chemical similarities between the interacting nuclei which may provide clues on the similar heating sources. Vibrationally excited transitions may be tracing the deeply embedded dust obscured active nuclei and/or hot compact star burst. This vibrational emission is the brightest ever measured in an extragalactic object, and even so compared with Galactic hot cores. In fact, the eastern one is the brightest in such vibrational emission. Water mega-maser emission also points towards a very compact sources likely related to star forming clumps within both Arp 220 nuclei.