Dwarf galaxies with ionizing radiation feedback. II. Spatially resolved star formation relation

Journal Article · Tue Dec 10 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/779/1/8· OSTI ID:22348566

Kim, Ji-hoon; Krumholz, Mark R.; Goldbaum, Nathan J. ^[1]; Wise, John H. ^[2]; Turk, Matthew J. ^[3]; Abel, Tom ^[4]

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1. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
2. Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)
3. Department of Astronomy and Astrophysics, Columbia University, New York, NY 10027 (United States)
4. Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States)

We investigate the spatially resolved star formation relation using a galactic disk formed in a comprehensive high-resolution (3.8 pc) simulation. Our new implementation of stellar feedback includes ionizing radiation as well as supernova explosions, and we handle ionizing radiation by solving the radiative transfer equation rather than by a subgrid model. Photoheating by stellar radiation stabilizes gas against Jeans fragmentation, reducing the star formation rate (SFR). Because we have self-consistently calculated the location of ionized gas, we are able to make simulated, spatially resolved observations of star formation tracers, such as Hα emission. We can also observe how stellar feedback manifests itself in the correlation between ionized and molecular gas. Applying our techniques to the disk in a galactic halo of 2.3 × 10{sup 11} M {sub ☉}, we find that the correlation between SFR density (estimated from mock Hα emission) and H{sub 2} density shows large scatter, especially at high resolutions of ≲75 pc that are comparable to the size of giant molecular clouds (GMCs). This is because an aperture of GMC size captures only particular stages of GMC evolution and because Hα traces hot gas around star-forming regions and is displaced from the H{sub 2} peaks themselves. By examining the evolving environment around star clusters, we speculate that the breakdown of the traditional star formation laws of the Kennicutt-Schmidt type at small scales is further aided by a combination of stars drifting from their birthplaces and molecular clouds being dispersed via stellar feedback.

• OSTI ID: 22348566
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 779; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BREAKDOWN
CAPTURE
CORRELATIONS
DENSITY
EMISSION
EXPLOSIONS
FEEDBACK
FRAGMENTATION
GALAXIES
IONIZING RADIATIONS
RADIANT HEAT TRANSFER
RESOLUTION
SIMULATION
STAR CLUSTERS
STAR EVOLUTION
STARS
STELLAR RADIATION