Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published February 1, 2019 | Published
Journal Article Open

Keck OSIRIS AO LIRG Analysis (KOALA): Feedback in the Nuclei of Luminous Infrared Galaxies

Abstract

The role of feedback in triggering or quenching star formation and hence driving galaxy evolution can be directly studied with high-resolution integral field observations. The manifestation of feedback in shocks is particularly important to examine in galaxy mergers, where violent interactions of gas take place in the interstellar medium during the course of the galactic collision. As part of our effort to systematically study the local population of luminous infrared galaxies within the Great Observatories All-Sky LIRG Survey, we undertook the Keck OSIRIS AO LIRG Analysis observing campaign to study the gas dynamics in the inner kiloparsec regions of these systems at spatial scales of a few tens of pc. With high-resolution near-infrared adaptive optics–assisted integral field observations taken with OSIRIS on the Keck Telescopes, we employ near-infrared diagnostics such as Brγ and the rovibrationally excited H_2 lines to quantify the nuclear star formation rate and identify feedback associated with shocked molecular gas seen in 21 nearby luminous infrared galaxies. Shocked molecular gas is preferentially found in the ultraluminous infrared systems but may also be triggered at a lower-luminosity, earlier merging stage. On circumnuclear scales, AGNs have a strong effect on heating the surrounding molecular gas, though their coupling is not simply driven by AGN strength but rather is complicated by orientation, dust shielding, density, and other factors. We find that nuclear star formation correlates with merger class and diminishing projected nuclear separations. These trends are largely consistent with the picture of merger-induced starbursts in the center of galaxy mergers.

Additional Information

© 2019. The American Astronomical Society. Received 2018 August 1; revised 2018 November 8; accepted 2018 November 16; published 2019 January 29. We thank the anonymous referee and the statistical editor for thoughtful suggestions that significantly improved our manuscript. We appreciate informative discussions with B. Groves and P. Creasey regarding photoionization models and wish to acknowledge helpful communication with D. Calzetti regarding dust extinction curves. We thank all of the Keck staff for help with carrying out the observations. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We also acknowledge the Evans Remote Observing Room at UC Irvine for a number of the remote observing sessions carried out there. VU acknowledges funding support from the University of California Chancellor's Postdoctoral Fellowship, JPL Contract/IRAC GTO grant No. 1256790, and NSF grant AST-1412693. Support for AMM is provided by NASA through Hubble Fellowship grant #HST-HF2-51377, awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. TD-S acknowledges support from ALMA-CONICYT project 31130005 and FONDECYT project 1151239. GCP acknowledges support from the University of Florida. This work was conducted in part at the Aspen Center for Physics, which is supported by NSF grant PHY-1607611; we thank the center for its hospitality during the Astrophysics of Massive Black Hole Mergers workshop in 2018 June and July. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Facilities: Keck: I/II (OSIRIS - , AO) - .

Attached Files

Published - U_2019_ApJ_871_166.pdf

Files

U_2019_ApJ_871_166.pdf
Files (1.8 MB)
Name Size Download all
md5:f3d0095416cba333cbc2f7b8018b20f4
1.8 MB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023