NOAO >   Observing Info >   Approved Programs >   2010A-0344

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Proposal Information for 2010A-0344


PI: Swara Ravindranath, Inter-University Center for Astronomy & Astrophysics, swara@iucaa.ernet.in
Address: IUCAA, Post Bag - 4, Ganeshkhind, Pune, Maharashtra 411007, India

CoI: Jayadev Rajagopal, NOAO/CTIO, Chile
CoI: Susan Ridgway, NOAO/CTIO, Chile

Title: Mid-IR Mapping of Nuclear Rings: Does Star Formation proceed by Sequential Triggering?

Abstract: Most of the star formation at high redshifts occurs in intense starbursts which play a major role in galaxy formation and evolution. Starbursts are very often heavily dust-obscured, making it difficult to study them at optical wavelengths. Nuclear rings in barred spirals are the ideal local analogs where starbursts can be studied at high- resolution from UV/optical through mid-IR. We propose to use the Gemini- S/TReCS to carry out mid-IR imaging of the PAH emission at 11.3 (mu)m, in the nuclear rings in four galaxies. The sample selection is based on (1) availability of HST images in the optical-NIR broad-band, and H- alpha (or Paschen-alpha) or UV, (2) the nuclear ring sizes are well- within the TReCS FOV, and (3) target accessibility. Our goal is to use the mid-IR images along with the HST data to; (1) identify the youngest (<6-8 Myrs) star clusters that reside in the most obscured regions using the mid-IR, (2) look for spatial offsets in the mid-IR bright (young) and optical/NIR-bright (intermediate-age) clusters, as is expected if star formation in the rings proceed by sequential triggering,(3) Use the 11.3 (micron) emission to derive the star formation rates (SFRs), and compare with the estimates from UV/optical SFR diagnostics to quantify the effect of dust-obscuration.Our results will probe the spatial and temporal evolution of starbursts in nuclear rings, and has significant implications for secular evolution, and formation of pseudobulges.


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