Assigned ID: 672 ----- Attempting Submission 1 (Fri Feb 26 22:04:44 GMT 2010) ----- HST Phase I Proposal 672 (nova.apt) successfully submitted. ----- Attempting Submission 2 (Fri Feb 26 23:37:09 GMT 2010) ----- Classical novae are luminous probes of the evolved stellar populations in external galaxies. Ground-based surveys suggest that the luminosity specific nova rate (LSNR) is roughly constant across Hubble type, with the possible exception of late-type irregular galaxies like the Magellanic Clouds. But some preliminary HST studies suggest that the nova rate in M87 may be a factor of 3 higher (or even more). We propose to study the nova population in the deep, multi-epoch ACS V and I band images of M87 obtained during the course of GO-10543 (PI: Baltz) for a microlensing survey. The GO program surveyed the galaxy daily in both V (1440s per day) and I (500s per day) for 45 consecutive days, with a few additional observations at other epochs, for a total baseline of 72 days. This study will likely yield the statistically best defined nova population in any galaxy studied to date, and definitively answer whether M87 is a particularly prolific nova factory. We will also search for novae in the roughly 2000 globular clusters (GC) within the M87 field. The discovery of a single nova in an M87 GC to date hints that GCs may be two orders of magnitude more efficient at producing novae than field stars. The discovery of additional GC candidate(s) will confirm that dynamical interactions in GCs enhance the rate of nova formation (and that of some of their close cousins like single degenerate Type Ia supernovae and CVs). Finally, we will compare the nova population of M87 to an extant WFPC2 study of novae in M49 to investigate whether the apparent factor of 3 difference in the nova rate can be attributed to novae that are spawned in the high specific frequency M87 globular cluster system and subsequently injected into the field. We estimate that, depending on the nova rate, we will detect at least 20, and possibly more than 100 novae in this data set.

UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 12 55500 false 0.0 0.0 false false false false false false SUPPORTED