KINEMATIC DISTANCES TO MOLECULAR CLOUDS IDENTIFIED IN THE GALACTIC RING SURVEY

By J. Roman-Duval, J. Jackson, M. Heyer, A. Johnson, J. Rathborne, R. Shah, R. Simon. 2009

168 citations recorded by the source corpus.

Kinematic distances to 750 molecular clouds identified in the 13CO J = 1 → 0 Boston University–Five College Radio Astronomy Observatory Galactic Ring Survey (GRS) are derived assuming the Clemens rotation curve of the Galaxy. The kinematic distance ambiguity is resolved by examining the presence of H i self-absorption toward the 13CO emission peak of each cloud using the Very Large Array Galactic Plane Survey. We also identify 21 cm continuum sources embedded in the GRS clouds in order to use absorption features in the H i 21 cm continuum to distinguish between near and far kinematic distances. The Galactic distribution of GRS clouds is consistent with a four-arm model of the Milky Way. The locations of the Scutum-Crux and Perseus arms traced by GRS clouds match star-count data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire star-count data. We conclude that molecular clouds must form in spiral arms and be short-lived (lifetimes < 107 yr) in order to explain the absence of massive, 13CO bright molecular clouds in the interarm space.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/2778b49668a175a8f016903130ca5576ecb69d0e

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Citations in the corpus

• A LARGE CATALOG OF ACCURATE DISTANCES TO MOLECULAR CLOUDS FROM PS1 PHOTOMETRY (2014, methodology): “This technique is widely applicable and has been used to estimate the distances to large numbers of molecular clouds (e.g., Roman-Duval et al. 2009); but it is problematic in the presence of peculiar velocities and non-circular motions.”
• PHYSICAL PROPERTIES OF MOLECULAR CLOUDS FOR THE ENTIRE MILKY WAY DISK (2016, methodology): “Following Roman-Duval et al. (2009), the galactocentric radius of a cloud is Rgal = R0 sin(l) V(r) vp + V0 sin(l) (19) where vp = 〈v〉/ cos(b) is the velocity component of the cloud in the plane of the Galaxy, and R0 = 8.5 kpc and V0 = 220 km s−1 are, respectively, the galactocentric radius and the…”
• Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey (2012, methodology): “Some clumps are located within GRS molecular clouds, whose kinematic distances have already been determined by using absorption features in the HI 21 cm line against continuum emission (Roman-Duval et al. 2009).”
• ATLASGAL - properties of a complete sample of Galactic clumps (2017, methodology): “…(16) Kolpak et al. (2003); (17) Pandian et al. (2009); (18) Sewilo et al. (2004); (19) Moisés et al. (2011); (20) Pandian et al. (2008); (21) Roman-Duval et al. (2009); (22) Stead & Hoare (2010); (23) Sanna et al. (2009); (24) Sato et al. (2010); (25) Urquhart et al. (2012); (26) Watson et…”
• The observed spiral structure of the Milky Way (2014, methodology): “The kinematic distance ambiguity for many HII regions, GMCs, and 6.7 GHz methanol masers has been solved (e.g., Roman-Duval et al. 2009; Lépine et al. 2011; Green & McClure-Griffiths 2011; Anderson et al. 2012; Urquhart et al. 2012; Jones & Dickey 2012), which enables us to estimate their kinematic…”
• ATLASGAL — towards a complete sample of massive star forming clumps ⋆ (2014, unknown): “…compilation of maser parallax (e.g. Reid et al. 2009), spectrophotometric (e.g. Moisés et al. 2011) and kinematic distances taken from the literature (e.g. Roman-Duval et al. 2009; Green & McClure-Griffiths 2011) and the RMS project’s own analysis (see Urquhart et al. 2012, 2014 for more details).”
• The 6-GHz methanol multibeam maser catalogue – II. Galactic longitudes 6° to 20° (2010, background): “In contrast Roman-Duval et al. (2009) identify it as a near-side object based on the ‘on-off’ HI self absorption technique, as do Solomon et al. (1987) based on a line-width to distance relation.”
• Molecular Clouds in the Milky Way (2015, background): “These surveys allow the ambiguity to be resolved for the majority of inner Galaxy GMCs from either HI self-absorption produced by the cloud itself or foreground absorption against associated continuum sources (Roman-Duval et al. 2009).”
• THE WISE CATALOG OF GALACTIC H ii REGIONS (2013, unknown): “…Sato et al. 2010a; (31) Sato et al. 2010b; (32) Sewilo et al. 2004b; (33) Shiozaki et al. 2011; (34) Urquhart et al. 2012; (35) Urquhart et al. 2012/Roman-Duval et al. 2009; (36) Watson et al. 2003; (37) Wu et al. 2012; (38) Xu et al. 2006; (39) Xu et al. 2009; (40) Xu et al. 2011; (41) Xu et…”
• The RMS survey : Galactic distribution of massive star formation (2013, background): “…are a number of ways to resolve these KDAs: H I absorption against a continuum (e.g. Fish et al. 2003; Kolpak et al. 2003; Anderson & Bania 2009; Roman-Duval et al. 2009; Urquhart et al. 2012), H I self-absorption (e.g. Jackson et al. 2002; RomanDuval et al. 2009; Green & McClure-Griffiths…”
• PHYSICAL PROPERTIES AND GALACTIC DISTRIBUTION OF MOLECULAR CLOUDS IDENTIFIED IN THE GALACTIC RING SURVEY (2010, methodology): “The theoretical implications of the enhancement of the Galactic surface mass density of molecular gas along spiral arms have been discussed in Roman-Duval et al. (2009): the confinement of molecular clouds to spiral arms suggests that molecular clouds must form in spiral arms via a combination of…”