Clumpy, Dense Gas in the Outflow of NGC 1266
Journal article, 2026
Outflows are one of the most spectacular mechanisms through which active galactic nuclei (AGN) impact their host galaxy, though the role of AGN-driven outflows in global star formation regulation across the galaxy population is unclear. NGC 1266 is an excellent case study for investigating outflows and star formation quenching because it is a nearby (D similar to 30 Mpc) AGN host galaxy with an outflow driving shocks through the interstellar medium (ISM) and has recently quenched its star formation outside the nucleus. While previous works have studied the molecular outflow from its CO emission, to fully characterize the impact the outflow has on the ISM observations probing the dense, cold gas are necessary. Our Atacama Large Millimeter/submillimeter Array Cycle 0 observations do not detect a molecular outflow in (CO)-C-13(2-1) and yield a lower limit of (CO)-C-12/(CO)-C-13 >= 250, suggesting a highly optically thin CO outflow with low (CO)-C-13 abundance. In contrast, we detect substantial HCN(1-0) emission in the outflow, with an HCN(1-0)/(CO)-C-12(1-0) ratio of 0.09, consistent with global measurements of many star-forming galaxies and luminous infrared galaxies. We conclude that the CO emission traces a diffuse component of the molecular gas with a low optical depth, whereas the HCN(1-0) traces dense clumps of gas entrained in the outflow. We measure an upper limit molecular outflow rate of <85 M-circle dot yr(-1). Assuming the ongoing nuclear star formation and outflow continue at the same rates, NGC 1266 will deplete its gas reservoir in 450 Myr or longer, indicating that relatively low-level AGN feedback is capable of gradually expelling the molecular gas reservoir after a rapid quenching event.
Author
Justin Atsushi Otter
Johns Hopkins University
Katherine Alatalo
Johns Hopkins University
Space Telescope Science Institute (STScI)
Kate Rowlands
Space Telescope Science Institute (STScI)
Johns Hopkins University
Pallavi Patil
Johns Hopkins University
Maya Skarbinski
Johns Hopkins University
Lauren Dysarz
University of California
Johns Hopkins University
Mark Lacy
National Radio Astronomy Observatory
Maria J. Jimenez-Donaire
Space Telescope Science Institute (STScI)
Spanish National Observatory (OAN)
Susanne Aalto
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Timothy A. Davis
Cardiff University
Antoniu Fodor
University of Toledo
K. Decker French
University of Illinois
Nanase Harada
The Graduate University for Advanced Studies (SOKENDAI)
National Astronomical Observatory of Japan
Timothy Heckman
Johns Hopkins University
Arizona State University
Ryo Kishikawa
University of Tokyo
National Astronomical Observatory of Japan
Sebastian Lopez
Ohio State University
Yuanze Luo
Texas A&M University
Sergio Martin
European Southern Observatory Santiago
Atacama Large Millimeter-submillimeter Array (ALMA)
Anne M. Medling
University of Toledo
Kristina Nyland
Naval Research Laboratory
Andreea Petric
Space Telescope Science Institute (STScI)
Namrata Roy
Arizona State University
Johns Hopkins University
Mamiko Sato
Elizaveta Sazonova
University of Waterloo
Adam Smercina
Space Telescope Science Institute (STScI)
Akshat Tripathi
University of Illinois
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 997 2 361Subject Categories (SSIF 2025)
Atom and Molecular Physics and Optics
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4357/ae2c5a