Skip to main content

Dense Molecular Gas Tracers in the Outflow of the Starburst Galaxy NGC 253

Author(s): Walter, Fabian; Bolatto, Alberto D; Leroy, Adam K; Veilleux, Sylvain; Warren, Steven R; et al

To refer to this page use:
Abstract: We present a detailed study of a molecular outflow feature in the nearby starburst galaxy NGC 253 using ALMA. We find that this feature is clearly associated with the edge of NGC 253’s prominent ionized outflow, has a projected length of similar to 300 pc, with a width of similar to 50 pc, and a velocity dispersion of similar to 40 km s(-1), which is. consistent with an ejection from the disk about 1 Myr ago. The kinematics of the molecular gas in this feature can be interpreted (albeit not uniquely) as accelerating at a rate of 1 km s(-1) pc(-1). In this scenario, the gas is approaching an escape velocity at the last measured point. Strikingly, bright tracers of dense molecular gas (HCN, CN, HCO+, CS) are also detected in the molecular outflow: we measure an HCN(1-0)/CO(1-0) line ratio of similar to 1 10 in the outflow, similar to that in the central starburst region of NGC 253 and other starburst galaxies. By contrast, the HCN/CO line ratio in the NGC 253 disk is significantly lower (similar to 1 30), similar to other nearby galaxy disks. This strongly suggests that the streamer gas originates from the starburst, and that its physical state does not change significantly over timescales of similar to 1 Myr during its entrainment in the outflow. Simple calculations indicate that radiation pressure is not the main mechanism for driving the outflow. The presence of such dense material in molecular outflows needs to be accounted for in simulations of galactic outflows.
Publication Date: 1-Feb-2017
Electronic Publication Date: 1-Feb-2017
Citation: Walter, Fabian, Bolatto, Alberto D, Leroy, Adam K, Veilleux, Sylvain, Warren, Steven R, Hodge, Jacqueline, Levy, Rebecca C, Meier, David S, Ostriker, Eve C, Ott, Jurgen, Rosolowsky, Erik, Scoville, Nick, Weiss, Axel, Zschaechner, Laura, Zwaan, Martin. (2017). Dense Molecular Gas Tracers in the Outflow of the Starburst Galaxy NGC 253. ASTROPHYSICAL JOURNAL, 835 (10.3847/1538-4357/835/2/265
DOI: doi:10.3847/1538-4357/835/2/265
ISSN: 0004-637X
EISSN: 1538-4357
Related Item:
Type of Material: Journal Article
Journal/Proceeding Title: ASTROPHYSICAL JOURNAL
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.