Physics
Scientific paper
Jun 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005sptz.prop20577r&link_type=abstract
Spitzer Proposal ID #20577
Physics
Scientific paper
We have identified a rare category of galaxies characterized by an extreme deficiency in synchro- tron radiation, relative to dust emission, and very high dust temperatures. We studied in detail the most extreme such object, and concluded in favor of a starburst just breaking out, less than one megayear old, in a galaxy having undergone no major star formation episode in the last 100 Myr. Such systems offer a perfect setting to study the initial conditions and early dynamics of starbursts and understand better the regulation of the infrared-radio continuum correlation in galaxies. For the prototypical nascent starburst, the mid-infrared spectrum is quite peculiar, suggesting tran- sient dust species and high optical depth; tracers of dust and molecular gas are the only indicators of unusual activity, and the active regions are likely very compact and dust-bounded, suppressing ionization. Only Spitzer data can provide the needed physical diagnostics for such regions. A sample of 25 nascent starbursts was drawn from the cross-correlation of the IRAS Faint Source Catalog and the NVSS VLA radio survey, and carefully selected based on our multi-wavelength VLA maps to span a range of infrared to radio ratios and luminosities. This sample allows a first step beyond studying prototypes toward a statistical analysis addressing systematic physical pro- perties, classification and search for starburst development sequences. We propose imaging and spectroscopic observations from 3 to 160 microns to characterize the state of the interstellar medium and the gas and dust excitation origin. Our aim is to learn from these unique systems how a star formation burst may develop in its very earliest phases, how it affects the fueling material and the host galaxy. Acquired observations of the radio continuum, cold molecular gas and tracers of shocks and HII regions will help us interpret the rich Spitzer data set and extract a coherent picture of the interstellar medium in our targets.
Beck Rainer
Condon Jim
Helou George
Roussel Helene
Smith John-David
No associations
LandOfFree
Nascent starbursts: a missing link in galaxy evolution does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Nascent starbursts: a missing link in galaxy evolution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nascent starbursts: a missing link in galaxy evolution will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1167379