Speaker
Deidre Hunter
(Lowell Observatory)
Description
Metallicity is not a passive result of galaxy evolution, but a crucial driver. Dwarf galaxies are low in heavy elements, which has consequences for the ability to form cold, dense clouds that form stars. Molecular cores shrink and atomic envelopes grow in star-forming clouds as the metallicity drops (Bolatto et al. 2011). For this reason, CO had not been detected at log(O/H)+12 < 8.0 (Schruba et al. 2012). We have now broken this metallicity barrier with CO 3-2 detections in two regions of the nearby dwarf galaxy WLM, which has log(O/H)+12 = 7.8 (Elmegreen et al. 2013). We present these observations and the analysis of sub-mm and FIR observations that allowed us to estimate the cloud masses to be of order 10^5 Msolar. Our Herschel [CII]158 micron map of the photo-dissociation region of one of our CO detections shows directly the extended envelope of the molecular cloud (Cigan et al, in prep and this meeting).
Author
Deidre Hunter
(Lowell Observatory)