H-Alpha Imaging Survey of Early-Type(Sa-Sab) Spiral Galaxies


We are conducting an H-Alpha survey of a complete sample of 57 bright (m(B) < 12.1 mag.), nearby (D < 40 Mpc), early-type(Sa-Sab) spiral galaxies.

MOTIVATION:

This survey is motivated by a recent analysis of the IRAS database by Devereux & Hameed 1997 (AJ 113, 599), which suggests that the global massive star formation rates in early-type spirals are comparable to the global massive star formation rates in late-type spirals.

WHY USE H-Alpha:

The use of the far infrared luminosity as a tracer of high mass star formation is still being debated in the literature. Therefore, we are imaging these galaxies in H-Alpha, which is a less controversial tracer of high mass star formation.

The H-Alpha images reveal the morphology and luminosity of the hydrogen gas. The H-Alpha flux provides a measure of the massive star formation rate, but it will be a lower limit because of extinction. The continuum images elucidate large scale morphological features such as stellar bars and bulges and evidence for interactions.


Images from the Survey



Back to Star formation page