A COMPARATIVE STUDY OF KNOTS OF STAR FORMATION IN INTERACTING VERSUS SPIRAL GALAXIES
- Department of Physics and Astronomy, East Tennessee State University, Johnson City TN 37614 (United States)
- Instituto de Astrofisica de Canarias, La Laguna, Tenerife (Spain)
- Department of Physics and Astronomy, Iowa State University, Ames IA 50011 (United States)
Interacting galaxies are known to have higher global rates of star formation on average than normal galaxies, relative to their stellar masses. Using UV and IR photometry combined with new and published Hα images, we have compared the star formation rates (SFRs) of ∼700 star forming complexes in 46 nearby interacting galaxy pairs with those of regions in 39 normal spiral galaxies. The interacting galaxies have proportionally more regions with high SFRs than the spirals. The most extreme regions in the interacting systems lie at the intersections of spiral/tidal structures, where gas is expected to pile up and trigger star formation. Published Hubble Space Telescope images show unusually large and luminous star clusters in the highest luminosity regions. The SFRs of the clumps correlate with measures of the dust attenuation, consistent with the idea that regions with more interstellar gas have more star formation. For the clumps with the highest SFRs, the apparent dust attenuation is consistent with the Calzetti starburst dust attenuation law. This suggests that the high luminosity regions are dominated by a central group of young stars surrounded by a shell of clumpy interstellar gas. In contrast, the lower luminosity clumps are bright in the UV relative to Hα, suggesting either a high differential attenuation between the ionized gas and the stars, or a post-starburst population bright in the UV but faded in Hα. The fraction of the global light of the galaxies in the clumps is higher on average for the interacting galaxies than for the spirals. Thus either star formation in interacting galaxies is “clumpier” on average, or the star forming regions in interacting galaxies are more luminous, dustier, or younger on average.
- OSTI ID:
- 22519997
- Journal Information:
- Astronomical Journal (Online), Vol. 151, Issue 3; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
STAR FORMATION AND DUST OBSCURATION IN THE TIDALLY DISTORTED GALAXY NGC 2442
GOODS-HERSCHEL MEASUREMENTS OF THE DUST ATTENUATION OF TYPICAL STAR-FORMING GALAXIES AT HIGH REDSHIFT: OBSERVATIONS OF ULTRAVIOLET-SELECTED GALAXIES AT z {approx} 2