# LOCAL INSTABILITY SIGNATURES IN ALMA OBSERVATIONS OF DENSE GAS IN NGC 7469 Journal article, 2015

We present an unprecedented measurement of the disk stability and local instability scales in the luminous infrared Seyfert 1 host, NGC 7469, based on ALMA observations of dense gas tracers and with a synthesized beam of 165 × 132 pc. While we confirm that non-circular motions are not significant in redistributing the dense interstellar gas in this galaxy, we find compelling evidence that the dense gas is a suitable tracer for studying the origin of its intensely high-mass star-forming ringlike structure. Our derived disk stability parameter $\mathcal{Q}$ accounts for a thick disk structure, and its value falls below unity at the radii in which intense star formation is found. Furthermore, we derive the characteristic instability scale ${\lambda }_{c}$ and find a striking agreement between our measured scale of ~180 pc and the typical sizes of individual complexes of young and massive star clusters seen in high-resolution images.

## Author

### K. Fathi

Stockholm Observatory

Stockholm University

### T. Izumi

University of Tokyo

### Alessandro Romeo

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

### S. Martin

Institut de RadioAstronomie Millimetrique (IRAM)

### M. Imanishi

National Astronomical Observatory of Japan

The Graduate University for Advanced Studies (SOKENDAI)

### E. Hatziminaoglou

European Southern Observatory (ESO)

### Susanne Aalto

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

National Astronomical Observatory of Japan

The Graduate University for Advanced Studies (SOKENDAI)

Atacama Large Millimeter-submillimeter Array (ALMA)

### K. Kohno

University of Tokyo

Research Center for the Early Universe

### Melanie Krips

Institut de RadioAstronomie Millimetrique (IRAM)

### D. S. Meier

New Mexico Institute of Mining and Technology

### N. Nakai

Faculty of Pure and Applied Sciences

### Y. Terashima

Ehime University

#### Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 806 2 L34 (6pp)- L34

### Subject Categories

Astronomy, Astrophysics and Cosmology

Basic sciences

### DOI

10.1088/2041-8205/806/2/L34