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

University of Virginia

National Radio Astronomy Observatory

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 at Irvine (UCI)

U. Vivian

University of California at Irvine (UCI)

Aaron S. Evans

National Radio Astronomy Observatory

University of Virginia

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

University of Crete

Foundation for Research and Technology-Hellas (FORTH)

European University Cyprus

T. Diaz-Santos

Foundation for Research and Technology-Hellas (FORTH)

European University Cyprus

Justin Howell

California Institute of Technology (Caltech)

G. Privon

College of Liberal Arts and Sciences

University of Virginia

National Radio Astronomy Observatory

C. Ricci

Diego Portales University

Beijing University of Technology

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 at Irvine (UCI)

J. Mazzarella

California Institute of Technology (Caltech)

Francisco Muller-Sanchez

College of Arts &amp; Sciences

D. B. Sanders

University of Hawaii

Astrophysical Journal

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

Vol. 977 1 36

Exploring 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

More information

Latest update

12/11/2024