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Title: THE INTERSTELLAR BUBBLES OF G38.9-0.4 AND THE IMPACT OF STELLAR FEEDBACK ON STAR FORMATION

We present a study of the star formation (SF) region G38.9-0.4 using publicly available multiwavelength Galactic plane surveys from ground- and space-based observatories. This region is composed of four bright mid-IR bubbles and numerous infrared dark clouds. Two bubbles, N 74 and N 75, each host a star cluster anchored by a single O9.5V star. We identified 162 young stellar objects (YSOs) and classify 54 as stage I, 7 as stage II, 6 as stage III, and 32 as ambiguous. We do not detect the classical signposts of triggered SF, i.e., star-forming pillars or YSOs embedded within bubble rims. We conclude that feedback-triggered SF has not occurred in G38.9-0.4. The YSOs are preferentially coincident with infrared dark clouds. This leads to a strong correlation between areal YSO mass surface density and gas mass surface density with a power law slope near 1.3, which closely matches the Schmidt-Kennicutt Law. The correlation is similar inside and outside the bubbles and may mean that the SF efficiency is neither enhanced nor suppressed in regions potentially influenced by stellar feedback. This suggests that gas density, regardless of how it is collected, is a more important driver of SF than stellar feedback. Larger studies shouldmore » be able to quantify the fraction of all SF that is feedback-triggered by determining the fraction SF, feedback-compressed gas surrounding H II regions relative to that already present in molecular clouds.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Department of Physics and Astronomy, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071 (United States)
  2. Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)
  3. Adler Planetarium, 1300 South Lake Shore Drive, Chicago, IL 60605 (United States)
Publication Date:
OSTI Identifier:
22127186
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 770; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BUBBLES; CORRELATIONS; DENSITY; FEEDBACK; MASS; STAR CLUSTERS; STARS; SURFACES