aas calzetti

Star Formation and Starburst Galaxies in the Infrared: 

Star Formation and Starburst Galaxies in the Infrared Daniela Calzetti (STScI) 199th AAS Meeting, Washington DC, January 9th 2002

The Unanswered Questions in Star Formation : 

The Unanswered Questions in Star Formation What are the regulating mechanisms of SF? What determines the intensity, duration (duty cycle) and spatial evolution (self-triggering?) of a SF event? What is the feedback of SF onto the host galaxy? How are these mechanisms tied to the global properties of the host galaxies? How many modes of SF there are? The answers will also provide recipes for galaxy evolution models

Slide3: 

Nuclear region of M83 (D~4 Mpc) Answering requires the study of the age distributions and SF history of the young stellar populations in galaxies How to approach the problem for unresolved pops? N.B.: dust-age degeneracy!

The Impact of Dust Obscuration: 

The Impact of Dust Obscuration Dust removes 20% -50% of stellar light in Local Galaxies Regions of star formation are the most heavily obscured.

The Advantage of Multi-l Data: 

The Advantage of Multi-l Data Long baseline discriminates a dusty stellar population from an ageing one (e.g., U-B as age indicator)

Determining Ages and SFHs: 

Determining Ages and SFHs Stellar Clusters Diffuse Population

What SNAP Can Do: 

What SNAP Can Do Multi-l capability: discriminates age/dust, derives ages Spatial resolution ~HST WFPC2 in the optical and ~HST NICMOS/NIC2 in the IR, plus photometric stability: resolves individual stellar components (e.g., clusters) AB=29 mag with S/N=5 in 10,000 secs: detects a 104 Mo, 10 Myr old cluster at 12.5 Mpc and a 100 Myr old cluster at 5 Mpc Degree (arcmin in IR) FOV: Local Galaxies (beyond the Local Group) have sizes that range between a few arcmin and 30-40 arcmin

Age Maps: 

Age Maps Nuclear region of M83 (Harris et al. 2001) Mapping the SFH of local galaxies will unveil the nature of the star formation mechanisms as a function of galactic parameters.

Conclusions: 

Conclusions Regulating mechanisms of SF and their dependence on global galactic parameters are virtually unknown Age distributions and SF histories of young stellar populations in nearby galaxies will provide clues on those mechanisms Effective age determinations, for both resolved and unresolved populations, require homogeneous sets of multi-wavelength data, as those SNAP can provide