Water, methanol and dense gas tracers in the local ULIRG Arp 220: results from the new SEPIA Band 5 Science Verification campaign
Journal article, 2016

We present a line survey of the ultraluminous infrared galaxy Arp 220, taken with the newly installed SEPIA (Swedish-European Southern Observatory PI receiver for APEX) Band 5 instrument on APEX (Atacama Pathfinder Experiment). We illustrate the capacity of SEPIA to detect the 183.3 GHz H(2)O3(1,3)-2(2,0) line against the atmospheric H2O absorption feature. We confirm the previous detection of the HCN(2-1) line, and detect new transitions of standard dense gas tracers such as HNC(2-1), HCO+(2-1), CS(4-3), (CS)-S-34(4-3) and HC3N(20-19). We also detect HCN(2-1) v(2) = 1 and the 193.5 GHz methanol (4-3) group for the first time. The absence of time variations in the megamaser water line compared to previous observations seems to rule out an AGN nuclear origin for the line. It could, on the contrary, favour a thermal origin instead, but also possibly be a sign that the megamaser emission is associated with star-forming cores washed out in the beam. We finally discuss how the new transitions of HCN, HNC and HCO+ refine our knowledge of the interstellar medium physical conditions in Arp 220.

galaxies: ISM-galaxies: starburst

ISM: molecules

galaxies: individual: Arp 220


M. Galametz

European Southern Observatory (ESO)

Z. Y. Zhang

University of Edinburgh

European Southern Observatory (ESO)

K. Immer

European Southern Observatory (ESO)

E. Humphreys

European Southern Observatory (ESO)

Rebeca Aladro

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

C. De Breuck

European Southern Observatory (ESO)

A. Ginsburg

European Southern Observatory (ESO)

S. C. Madden

The French Alternative Energies and Atomic Energy Commission (CEA)

P. Moller

European Southern Observatory (ESO)

V. Arumugam

European Southern Observatory (ESO)

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 462 1 L36-L40

Driving Forces

Sustainable development

Subject Categories

Astronomy, Astrophysics and Cosmology



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