Detection of HCN, HCO+, and HNC in the Mrk 231 molecular outflow. Dense molecular gas in the AGN wind
Artikel i vetenskaplig tidskrift, 2012

We obtained high-resolution (1.''55 × 1.''28) observations of HCN, HCO+, HNC 1-0 and HC3N 10-9 of the ultraluminous galaxy (ULIRG) Mrk 231 with the IRAM Plateau de Bure Interferometer. Results: We detect luminous emission from HCN, HCO+ and HNC 1-0 in the QSO ULIRG Mrk 231. All three lines show broad line wings - which are particularly prominent for HCN. Velocities are found to be similar ( ≈ ± 750 km s-1) to those found for CO 1-0. This is the first time bright HCN, HCO+ and HNC emission has been detected in a large-scale galactic outflow. We find that both the blue- and red-shifted line wings are spatially extended by at least 0.''75 (>700 pc) in a north-south direction. The line wings are brighter (relative to the line center intensity) in HCN than in CO 1-0 and line ratios suggest that the molecular outflow consists of dense (n > 104 cm-3) and clumpy gas with a high HCN abundance X(HCN) > 10-8. These properties are consistent with the molecular gas being compressed and fragmented by shocks in the outflow. Alternatively, HCN is instead pumped by mid-IR continuum, but we propose that this effect is not strong for the spatially extended outflowing gas. In addition, we find that the rotation of the main disk, in east-west direction, is also evident in the HCN, HCO+ and HNC line emission. An unexpectedly bright HC3N 10-9 line is detected inside the central 400 pc of Mrk 231. This HC3N emission may emerge from a shielded, dust-enshrouded region within the inner 40-50 pc where the gas is heated to high temperatures (200-300 K) by the AGN.

radio lines: ISM

galaxies: evolution

galaxies: individual: Mrk 231

ISM: molecules

quasars: general

galaxies: active

Författare

Susanne Aalto

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

S. G. Burillo

Observatorio Astronomico Nacional

Sebastien Muller

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

J.M. Winters

IRAM Institut de RadioAstronomie Millimetrique

P. van der Werf

Leiden Observatory Research Institute

C. Henkel

Max Planck Institut fur Radioastronomie

King Abdulaziz University

Francesco Costagliola

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

R. Neri

IRAM Institut de RadioAstronomie Millimetrique

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 537 44-51 A44

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

DOI

10.1051/0004-6361/201117919