Query : 2000A&A...358..521B

2000A&A...358..521B - Astronomy and Astrophysics, volume 358, 521-534 (2000/6-2)

The radial distribution of OB star formation in the Galaxy.


Abstract (from CDS):

We present the azimuthally averaged radial distribution of 748 regions of OB star formation in the whole galactic disk, based on our previous CS(2-1) survey of UC H II regions. Embedded massive stars produce a total FIR luminosity of 1.39x108L within the range 0.2≤R/R0≤2 in galactocentric radius. We find 492 massive star forming regions within the solar circle, producing 81% of the total FIR luminosity. Separate analyses of the 349 sources in the I and II quadrant (north), and of the 399 sources in the III and IV quadrant (south), yield FIR luminosities (extrapolated to the complete galactic disk) of 1.17x108L and of 1.60x108L, respectively. Massive star formation is distributed in a layer with its centroid Z0(R) following that of molecular gas for all galactocentric radii, both north and south. Its thickness for R≤R0 is ∼73pc (FWHM), 62% the thickness of the molecular gas disk. The FIR luminosity produced by massive stars has a well defined maximum at R=0.55R0, with a gaussian FWHM of 0.28R0- compared with 0.51R0 for the H2 surface density distribution. Toward the outer Galaxy, down from the maximum, the face-on FIR surface luminosity decays exponentially with a scale length of 0.21R0, compared with 0.34R0 for the H2 surface density. Massive star formation per unit H2 mass is maximum for R∼0.55R0 in the southern Galaxy, with a FIR surface luminosity to H2 surface density ratio of ∼0.41L/M, compared with ∼0.21L/M at the same radius in the north, and with an average of ∼0.18L/M for the whole galactic disk within the solar circle.

Abstract Copyright:

Journal keyword(s): Galaxy: structure - infrared: ISM: continuum - ISM: clouds - ISM: HII regions - ISM: molecules - infrared: ISM: continuum

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 NAME Car Arm PoG 10 00 -60.0           ~ 407 1
2 NAME Crux Arm PoG 12 30 -60.0           ~ 88 0
3 NAME Nor Arm PoG 16 00 -50.0           ~ 380 0

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