Issue |
A&A
Volume 493, Number 1, January I 2009
|
|
---|---|---|
Page(s) | 33 - 37 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:200810457 | |
Published online | 06 November 2008 |
Density effect on multiwavelength luminosities on star-formation regions in NGC 3184 and NGC 3938
Instituto de Astronomía, Universidad Nacional Autónoma de México, México D. F., México e-mail: irene@astroscu.unam.mx
Received:
25
June
2008
Accepted:
2
October
2008
Aims. We analyzed the regions of star formation in the spiral galaxies NGC 3184and NGC 3938from archive images for a wide range of wavelengths (NUV from GALEX, Hα from JKT and KPNO, 8 and 24 μm from Spitzer, and CO from BIMA).
Methods. We used the Clump Find Algorithm to extract the properties of the star-forming tracers, identifiable as emission regions at each wavelength.
Results. We
obtained a power-law relation between the luminosity and the
emission region volume that scales as expected, , for
the Hα and NUV emission, but the luminosity varies far more
rapidly with the volume for the dust (8 and 24 μm) and
molecular gas emitting regions in CO. This is interpreted as a
change in the emissivity with the size of the cloud, either by an
augmentation of the overall density or due to the presence of high
density clumps, with high local emissivity coefficients. Although
the clumpy nature of molecular gas may be unsurprising, the clumpy
nature of mid-infrared emission regions, which could be explained
by newly formed high to intermediate mass stars embedded in the
dust providing the heating, is clearly revealed in both
galaxies.
Key words: galaxies: ISM / galaxies: fundamental parameters / galaxies: individual: NGC 3184 / galaxies: individual: NGC 3938 / stars: formation
© ESO, 2008
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