Molecular gas in the northern nucleus of Mrk 273: Physical and chemical properties of the disc and its outflow
Journal article, 2018

Aiming to characterise the properties of the molecular gas in the ultra-luminous infrared galaxy Mrk 273 and its outflow, we used the NOEMA interferometer to image the dense-gas molecular tracers HCN, HCO+, HNC, HOC+ and HC3N at similar to 86 GHz and similar to 256 GHz with angular resolutions of 4.'' 9 x 4.'' 5 (similar to 3.7 x 3.4 kpc) and 0.'' 61 x 0.'' 55 (similar to 460 x 420 pc). We also modelled the flux of several H2O lines observed with Herschel using a radiative transfer code that includes excitation by collisions and far-infrared photons. The disc of the Mrk 273 north nucleus has two components with decoupled kinematics. The gas in the outer parts (R similar to 1.5 kpc) rotates with a south-east to north-west direction, while in the inner disc (R similar to 300 pc) follows a north-east to south-west rotation. The central 300 pc, which hosts a compact starburst region, is filled with dense and warm gas, and contains a dynamical mass of (4-5) x 10(9) M-circle dot, a luminosity of L'HCN = (3-4) x 10(8) K km s(-1) pc(2), and a dust temperature of 55 K. At the very centre, a compact core with R similar to 50 pc has a luminosity of LIR = 4 x 10(11) L-circle dot (30% of the total infrared luminosity), and a dust temperature of 95 K. The core is expanding at low velocities similar to 50-100 km s(-1), probably affected by the outflowing gas. We detect the blue-shifted component of the outflow, while the red-shifted counterpart remains undetected in our data. Its cold and dense phase reaches fast velocities up to similar to 1000 km s(-1), while the warm outflowing gas has more moderate maximum velocities of similar to 600 km s(-1). The outflow is compact, being detected as far as 460 pc from the centre in the northern direction, and has a mass of dense gas <= 8 x 10(8) M-circle dot. The difference between the position angles of the inner disc (similar to 70 degrees) and the outflow (similar to 10 degrees) indicates that the outflow is likely powered by the AGN, and not by the starburst. Regarding the chemistry in Mrk 273, we measure an extremely low HCO+/HOC+ ratio of 10 +/- 5 in the inner disc of Mrk 273.

galaxies: kinematics and dynamics

galaxies: individual: Mrk 273

galaxies: nuclei

line: profiles

ISM: molecules



Rebeca Aladro

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Max Planck Society

Sabine König

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Susanne Aalto

Chalmers, Space, Earth and Environment, Onsala Space Observatory

E. Gonzalez-Alfonso

University of Alcalá

Niklas Falstad

Chalmers, Space, Earth and Environment, Onsala Space Observatory

S. Martin

Atacama Large Millimeter-submillimeter Array (ALMA)

European Southern Observatory Santiago

Sebastien Muller

Chalmers, Space, Earth and Environment, Onsala Space Observatory

S. Garcia-Burillo

Spanish National Observatory (OAN)

C. Henkel

King Abdulaziz University

Max Planck Society

P. van der Werf

Leiden University

E. Mills

San Jose State University

J. Fischer

George Mason University

Francesco Costagliola

Chalmers, Space, Earth and Environment, Onsala Space Observatory

M. Krips

Old Dominion University

Astronomy and Astrophysics

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

Vol. 617 A20

RadioNet 4

European Commission (EC) (EC/H2020/730562), 2017-01-01 -- 2020-12-31.

Subject Categories

Energy Engineering

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics



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