The RMS survey : Galactic distribution of massive star formation

By J. Urquhart, C. Figura, T. T.J., M. Hoare, S. Lumsden, J. Mottram, M. Thompson, R. D. O. MPIfR, Wartburg College, Liverpool John Moore's University and 3 more. 2013

134 citations recorded by the source corpus.

We have used the well-selected sample of~1750 embedded, young, massive stars identified by the Red MSX Source (RMS) survey to investigate the Galactic distribution of recent massive star formation. We present molecular line observations for ~800 sources without existing radial velocities. We describe the various methods used to assign distances extracted from the literature and solve the distance ambiguities towards approximately 200 sources located within the solar circle using archival HI data. These distances are used to calculate bolometric luminosities and estimate the survey completeness (~2 × 10 4 L⊙). In total, we calculate the distance and luminosity of ~1650 sources, one third of which are above the survey's completeness threshold. Examination of the sample's longitude, latitude, radial velocities and mid-infrared images has identified~120 small groups of sources, many of which are associated with well-known star formation complexes, such as G305, G333, W31, W43, W49 and W51. We compare the positional distribution of the sample with the expected locations of the spiral arms, assuming a model of the Galaxy consisting of four gaseous arms. The distribution of young massive stars in the Milky Way is spatially correlated with the spiral arms, with strong peaks in the source position and luminosity distributions at the arms' Galactocentric radii. The overall source and luminosity surface densities are both well correlated with the surface density of the molecular gas, which suggests that the massive star formation rate per unit molecular mass is approximately constant across the Galaxy. A comparison of the distribution of molecular gas and the young massive stars to that in other nearby spiral galaxies shows similar radial dependences. We estimate the total luminosity of the embedded massive star population to be ~0.76 × 10 8 L⊙, 30 per cent of which is associated with the 10 most active star-forming complexes.We measure the scaleheight as a function of the Galactocentric distance and find that it increases only modestly from ~20-30 pc between 4 and 8 kpc, but much more rapidly at larger distances. © 2013 The Authors.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/261a7d953b9b4314a9d879fc0f93f51ca219fa3c

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Citations in the corpus

• ATLASGAL — towards a complete sample of massive star forming clumps ⋆ (2014, methodology): “Distances have already been obtained for the vast majority of the ATLASGAL–RMS matched sources (∼90 per cent; see Urquhart et al. 2014 for details).”
• The Nine Lives of Cosmic Rays in Galaxies (2015, background): “The surface density of potential CR sources is expected to rapidly decline beyond the solar circle, along with the star-formation rate (Urquhart et al. 2014).”
• A NEW ELECTRON-DENSITY MODEL FOR ESTIMATION OF PULSAR AND FRB DISTANCES (2016, background): “…scale heights in the range 50–70 pc at Galactocentric radii of 4–6 kpc, whereas mid-infrared observations of massive stars in the Galactic disk (e.g., Urquhart et al. 2014) and open star clusters (Joshi et al. 2016) give scale heights less than half as large, 20–25 pc.11 All of these tracers show…”
• Trigonometric Parallaxes of High-mass Star-forming Regions: Our View of the Milky Way (2019, methodology): “…masers from Valdettaro et al. (2001), methanol masers from Pestalozzi et al. (2005) and Green et al. (2017), HII regions from Anderson et al. (2012), and redMSX sources from Urquhart et al. (2014), we now construct an improved visualization of the spiral structure of the Galaxy, shown in Figure 10.”
• ATLASGAL - properties of a complete sample of Galactic clumps (2017, methodology): “…at specific Galactocentric radii (e.g., Moore et al. 2012, Urquhart et al. 2014b) and found to be concentrated along loci in longitude-velocity space (Urquhart et al. 2014c), both of which confirm the spiral structure of the Milky Way and its connection to the ongoing star formation in the Galaxy.”