GOALS-JWST: The Warm Molecular Outflows of the Merging Starburst Galaxy NGC 3256
Journal article, 2024
We present James Webb Space Telescope (JWST) integral-field spectrograph observations of NGC 3256, a local infrared-luminous late-stage merging system with two nuclei roughly 1 kpc apart, both of which have evidence of cold molecular outflows. Using JWST/NIRSpec and Mid-Infrared Instrument data sets, we investigate this morphologically complex system on spatial scales of <100 pc, where we focus on the warm molecular H2 gas surrounding the nuclei. We detect collimated outflowing warm H2 gas originating from the southern nucleus, though we do not find significant outflowing H2 gas surrounding the northern nucleus. We measure maximum intrinsic outflow velocities of ∼1000 km s−1, which extend out to a distance of 0.7 kpc. Based on H2 S(7)/S(1) ratios, we find a larger fraction of warmer gas near the southern nucleus, which decreases with increasing distance from the nucleus, signifying the southern nucleus as a primary source of H2 heating. The gas mass of the warm H2 outflow component is estimated to be M warm,out = (1.4 ± 0.2) × 106 M ⊙, as much as 6% of the cold H2 mass estimated using Atacama Large Millimeter/submillimeter Array CO data. The outflow timescale is about 7 × 105 yr, resulting in a mass outflow rate M ̇ warm , out = 2.0 ± 0.8 M ⊙ yr − 1 and kinetic power P warm,out ∼ 4 × 1041 erg s−1. Lastly, regions within our 3.″0 × 3.″0 NIRSpec data, where the outflowing gas reside show high [Fe ii]/Paβ and H2/Brγ line ratios, indicate enhanced mechanical heating caused by the outflows. The fluxes and ratios of polycyclic aromatic hydrocarbons (PAHs) in these regions are not significantly different compared to those elsewhere in the disk, suggesting the outflows may not significantly alter the PAH ionization state or grain size.
Author
Thomas Bohn
Hiroshima University
H. Inami
Hiroshima University
Aditya Togi
Texas State University
Lee Armus
California Institute of Technology (Caltech)
Thomas Lai
California Institute of Technology (Caltech)
Loreto Barcos-Munoz
National Radio Astronomy Observatory
University of Virginia
Y. Song
European Southern Observatory Santiago
Atacama Large Millimeter-submillimeter Array (ALMA)
S. T. Linden
University of Massachusetts
J. A. Surace
California Institute of Technology (Caltech)
Marina Bianchin
University of California
U. Vivian
University of California
Aaron S. Evans
University of Virginia
National Radio Astronomy Observatory
T. Boker
European Space Agency (ESA)
M. A. Malkan
University of California
K. Larson
Space Telescope Science Institute (STScI)
S. Stierwalt
Occidental College
Victorine A. Buiten
Leiden University
V. Charmandaris
Foundation for Research and Technology-Hellas (FORTH)
European University Cyprus
University of Crete
T. Diaz-Santos
European University Cyprus
Foundation for Research and Technology-Hellas (FORTH)
Justin Howell
California Institute of Technology (Caltech)
G. Privon
College of Liberal Arts and Sciences
University of Virginia
National Radio Astronomy Observatory
C. Ricci
Beijing University of Technology
Diego Portales University
P. van der Werf
Leiden University
Susanne Aalto
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Christopher C. Hayward
Flatiron Institute
Justin A. Kader
University of California
J. Mazzarella
California Institute of Technology (Caltech)
Francisco Muller-Sanchez
University of Memphis
D. B. Sanders
University of Hawaii
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 977 1 36Exploring the Hidden Dusty Nuclei of Galaxies (HIDDeN)
European Research Council (ERC) (789410), 2018-10-01 -- 2023-09-30.
Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.3847/1538-4357/ad87d3