New molecular species at redshift z = 0.89
Abstract
We present the first detections of CH3SH, C3H+, C3N, HCOOH, CH2CHCN, and H2CN in an extragalactic source. Namely the spiral arm of a galaxy located at z = 0.89 on the line of sight to the radio-loud quasar PKS 1830-211. OCS, SO2, and NH2CN were also detected, raising the total number of molecular species identified in that early time galaxy to 54, not counting isotopologues. The detections were made in absorption against the SW quasar image, at 2 kpc from the galaxy centre, over the course of a Q band spectral line survey made with the Yebes 40 m telescope (rest-frame frequencies: 58.7 - 93.5 GHz). We derived the rotational temperatures and column densities of those species, which are found to be subthermally excited. The molecular abundances, and in particular the large abundances of C3H+ and of several previously reported cations, are characteristic of diffuse or translucent clouds with enhanced UV radiation or strong shocks.
This paper is based on observations with the 40 m radio telescope of the National Geographic Institute of Spain (IGN) at Yebes Observatory. Yebes Observatory thanks the ERC for funding support under grant ERC-2013-Syg-610256-NANOCOSMOS.- Publication:
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Astronomy and Astrophysics
- Pub Date:
- April 2020
- DOI:
- 10.1051/0004-6361/202037837
- arXiv:
- arXiv:2004.02486
- Bibcode:
- 2020A&A...636L...7T
- Keywords:
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- astrochemistry;
- galaxies: abundances;
- galaxies: ISM;
- ISM: molecules;
- line: identification;
- quasars: individual: PKS 1830-211;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in A&