2020A&A...641A..53W


C.D.S. - SIMBAD4 rel 1.7 - 2020.12.05CET00:55:40

2020A&A...641A..53W - Astronomy and Astrophysics, volume 641A, 53-53 (2020/9-1)

Dense gas in a giant molecular filament.

WANG Y., BEUTHER H., SCHNEIDER N., MEIDT S.E., LINZ H., RAGAN S., ZUCKER C., BATTERSBY C., SOLER J.D., SCHINNERER E., BIGIEL F., COLOMBO D. and HENNING T.

Abstract (from CDS):


Context. Recent surveys of the Galactic plane in the dust continuum and CO emission lines reveal that large (≥50pc) and massive (≥105M) filaments, know as giant molecular filaments (GMFs), may be linked to Galactic dynamics and trace the mid-plane of the gravitational potential in the Milky Way. Yet our physical understanding of GMFs is still poor.
Aims. We investigate the dense gas properties of one GMF, with the ultimate goal of connecting these dense gas tracers with star formation processes in the GMF.
Methods. We imaged one entire GMF located at l∼52-54° longitude, GMF54 (∼68pc long), in the empirical dense gas tracers using the HCN(1-0), HNC(1-0), and HCO+(1-0) lines, and their 13C isotopologue transitions, as well as the N2H+(1-0) line. We studied the dense gas distribution, the column density probability density functions (N-PDFs), and the line ratios within the GMF.
Results. The dense gas molecular transitions follow the extended structure of the filament with area filling factors between 0.06 and 0.28 with respect to 13CO(1-0). We constructed the N-PDFs of H2 for each of the dense gas tracers based on their column densities and assumed uniform abundance. The N-PDFs of the dense gas tracers appear curved in log-log representation, and the HCO+ N-PDF has the flattest power-law slope index. Studying the N-PDFs for sub-regions of GMF54, we found an evolutionary trend in the N-PDFs that high-mass star-forming and photon-dominated regions have flatter power-law indices. The integrated intensity ratios of the molecular lines in GMF54 are comparable to those in nearby galaxies. In particular, the N2H+/13CO ratio, which traces the dense gas fraction, has similar values in GMF54 and all nearby galaxies except Ultraluminous Infrared Galaxies .
Conclusions. As the largest coherent cold gaseous structure in our Milky Way, GMFs, are outstanding candidates for connecting studies of star formation on Galactic and extragalactic scales. By analyzing a complete map of the dense gas in a GMF we have found that: (1) the dense gas N-PDFs appear flatter in more evolved regions and steeper in younger regions, and (2) its integrated dense gas intensity ratios are similar to those of nearby galaxies.

Abstract Copyright: © Y. Wang et al. 2020

Journal keyword(s): ISM: clouds - ISM: molecules - stars: formation - radio lines: ISM

VizieR on-line data: <Available at CDS (J/A+A/641/A53): list.dat fits/*>

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 IC 10 G 00 20 23.16 +59 17 34.7   13.6 9.5     ~ 1017 0
2 M 33 GiG 01 33 50.904 +30 39 35.79 6.17 6.27 5.72     ~ 5219 1
3 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15069 1
4 W 51 SNR 19 23 50 +14 06.0           ~ 1161 1
5 NAME Cyg X Cld 20 28 41 +41 10.2           ~ 635 1
6 NAME Cygnus X North MoC 20 37.0 +41 56           ~ 5 0
7 [RHT2014] GMF G038.1-32.4a ISM 20 57 -10.2           ~ 6 0
8 [RHT2014] GMF G054.0-52.0 ISM 22 29 -09.3           ~ 4 0

    Equat.    Gal    SGal    Ecl

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2020.12.05-00:55:40

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