Black hole accretion and star formation as drivers of gas excitation and chemistry in Markarian 231
Artikel i vetenskaplig tidskrift, 2010
We present a full high resolution SPIRE FTS spectrum of the nearby ultraluminous infrared galaxy Mrk 231. In total 25 lines are detected, including CO J = 5-4 through J = 13-12, 7 rotational lines of H2O, 3 of OH+ and one line each of H2O+, CH+, and HF. We find that the excitation of the CO rotational levels up to J = 8 can be accounted for by UV radiation from star formation. However, the approximately flat luminosity distribution of the CO lines over the rotational ladder above J = 8 requires the presence of a separate source of excitation for the highest CO lines. We explore X-ray heating by the accreting supermassive black hole in Mrk 231 as a source of excitation for these lines, and find that it can reproduce the observed luminosities. We also consider a model with dense gas in a strong UV radiation field to produce the highest CO lines, but find that this model strongly overpredicts the hot dust mass in Mrk 231. Our favoured model consists of a star forming disk of radius 560 pc, containing clumps of dense gas exposed to strong UV radiation, dominating the emission of CO lines up to J = 8. X-rays from the accreting supermassive black hole in Mrk 231 dominate the excitation and chemistry of the inner disk out to a radius of 160 pc, consistent with the X-ray power of the AGN in Mrk 231. The extraordinary luminosity of the OH+ and H2O+ lines reveals the signature of X-ray driven excitation and chemistry in this region.
diagnostics
galaxies: individual: Mrk 231
emission
galaxies: ISM
galaxies: starburst
infrared: galaxies
galaxy nuclei
galaxies: nuclei
galaxies: active
dense gas
lines
Författare
P.P. van der Werf
Universiteit Leiden
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
Cardiff University
R. Meijerink
Universiteit Leiden
M. Spaans
Rijksuniversiteit Groningen
A. Rykala
Cardiff University
T. Fulton
Blue Sky Spectroscopy
A. F. Loenen
Universiteit Leiden
F. Walter
Max-Planck-Gesellschaft
A. Weiss
Max-Planck-Gesellschaft
L. Armus
Spitzer Science Center
J. Fischer
Naval Research Laboratory
F. P. Israel
Universiteit Leiden
A. I. Harris
University of Maryland
S. Veilleux
University of Maryland
C. Henkel
Max-Planck-Gesellschaft
G. Savini
University College London (UCL)
S. Lord
California Institute of Technology (Caltech)
H. A. Smith
Harvard-Smithsonian Center for Astrophysics
E. Gonzalez-Alfonso
Universidad de Alcala
D. A. Naylor
University of Lethbridge
Susanne Aalto
Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik
V. Charmandaris
Panepistimio Kritis
K. M. Dasyra
Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)
A. Evans
National Radio Astronomy Observatory
University of Virginia
Y. Gao
Chinese Academy of Sciences
T. R. Greve
Max-Planck-Gesellschaft
Niels Bohr Institute
R. Güsten
Max-Planck-Gesellschaft
C. Kramer
Institut de Radioastronomie Millimétrique (IRAM)
J. Martin-Pintado
CSIC - Instituto de Estructura de la Materia (IEM)
J. Mazzarella
California Institute of Technology (Caltech)
P. P. Papadopoulos
Argelander-Institut für Astronomie
D. B. Sanders
University of Hawaii
L. Spinoglio
Consiglo Nazionale Delle Richerche
G. Stacey
Cornell University
C. Vlahakis
Universiteit Leiden
M. C. Wiedner
LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres
E. M. Xilouris
National Observatory of Athens
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 518 Article Number: L42 L42Ämneskategorier
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/201014682