Compact galaxies with active star formation from SDSS DR14: star formation rates derived from combinations of luminosities in different wavelength ranges

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.

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Physical and chemical properties of the AFGL 333 cloud

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307002591 ◽

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.

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Regions of active star formation in O associations. I

Astrophysics ◽

10.1007/bf01005994 ◽

1991 ◽

Vol 33 (1) ◽

pp. 319-324

Author(s):

A. V. Oskanyan

Keyword(s):

Star Formation ◽

Active Star ◽

Active Star Formation

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Regions of active star formation in O associations. II

Astrophysics ◽

10.1007/bf01019435 ◽

1991 ◽

Vol 33 (2) ◽

pp. 447-453

Author(s):

A. V. Oskanyan

Keyword(s):

Star Formation ◽

Active Star ◽

Active Star Formation

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Sub-Millimeter Spectral Line Observations in Very Dense Regions

Symposium - International Astronomical Union ◽

10.1017/s0074180900095322 ◽

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.

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