Regions of active star formation in O associations. II

Astrophysics ◽  
1991 ◽  
Vol 33 (2) ◽  
pp. 447-453
Author(s):  
A. V. Oskanyan
Keyword(s):  
Star Formation ◽  
Active Star ◽  
Active Star Formation

scholarly journals Star Formation Thresholds in Low Surface Brightness Dwarf Galaxies

1999 ◽  
Vol 171 ◽  
pp. 274-281
Author(s):  
Liese van Zee
Keyword(s):  
Star Formation ◽  
Comparative Study ◽  
Column Density ◽  
Surface Brightness ◽  
Dwarf Galaxies ◽  
Critical Threshold ◽  
Active Star ◽  
Comparison Sample ◽  
Active Star Formation ◽  
Low Surface Brightness

AbstractThe results of a comparative study of star formation thresholds in gas-rich, low surface brightness, dwarf galaxies are presented. Approximately half the galaxies in the study were “high MH/LB” galaxies, which appear to have inefficient star formation properties. The comparison sample comprised of otherwise “normal” dwarf galaxies, with moderate current star formation rates. In all systems, sites of active star formation were associated with local peaks in the HI column density. For both types of galaxies, the azimuthally averaged gas column density is low. Similar to other LSB systems, the global gas densities are well below the critical threshold for star formation throughout the system. Thus, star formation is inhibited globally, but occurs locally in these gas-rich dwarf galaxies.

scholarly journals Physical and chemical properties of the AFGL 333 cloud

2006 ◽  
Vol 2 (S237) ◽  
pp. 471-471
Author(s):  
Takeshi Sakai ◽  
Tomoharu Oka ◽  
Satoshi Yamamoto
Keyword(s):  
Star Formation ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Active Star ◽  
Active Star Formation ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractWe have found massive clumps without any sign of active star formation in the AFGL 333 cloud. We present a study of the physical and chemical properties of the AFGL 333 cloud.

Regions of active star formation in O associations. I

Astrophysics ◽  
1991 ◽  
Vol 33 (1) ◽  
pp. 319-324
Author(s):  
A. V. Oskanyan
Keyword(s):  
Star Formation ◽  
Active Star ◽  
Active Star Formation

scholarly journals Sub-Millimeter Spectral Line Observations in Very Dense Regions

1987 ◽  
Vol 115 ◽  
pp. 173-173
Author(s):  
Neal J. Evans ◽  
Lee G. Mundy ◽  
John H. Davis ◽  
Paul Vanden Bout
Keyword(s):  
Star Formation ◽  
Spectral Line ◽  
Millimeter Wave ◽  
Volume Density ◽  
High Density ◽  
Active Star ◽  
Millimeter Wavelengths ◽  
Active Star Formation ◽  
Very High

In a search for very high density (n ≳ 107 cm−3) regions, the Millimeter Wave Observatory 5-m telescope was used to observe several submillimeter lines. The regions studied were Orion A, M17, S140, and NGC2024. The lines were CS(J=7-6), H2CO(JK-1K1=515→414), and HCN(J=4-3). These data are combined with data at millimeter wavelengths to derive the volume density and the results are compared to those deduced from millimeter lines alone (Snell et al. 1984). In NGC2024, higher densities (≳ 107 cm−3) are clearly indicated by the sub-mm lines than were derived by Snell et al. In M17, derived densities are also higher, but uncertainties overlap the Snell et al. solutions. The range of densities derived from CS and HCN are consistent. The sub-millimeter lines of these species appear to be good probes of the highest densities present in regions of active star formation.

An active star formation site in RCW 108

1987 ◽  
Vol 314 ◽  
pp. 283 ◽  
Author(s):  
Steven Straw ◽  
A. R. Hyland ◽  
Terry J. Jones ◽  
Paul M. Harvey ◽  
Bruce A. Wilking ◽  
...  
Keyword(s):  
Star Formation ◽  
Active Star ◽  
Active Star Formation
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