Computer Science
Scientific paper
Jul 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996hst..prop.6536s&link_type=abstract
HST Proposal ID #6536
Computer Science
Hst Proposal Id #6536 Galaxies &Amp, Clusters
Scientific paper
I Zw 18 is host to the lowest metallicity H II region known, and, therefore, is pivotal in studies of the chemical evolution of galaxies, the primordial He abundance, and low metallicity stellar populations. Our previous HST observations of I Zw 18 have allowed us to establish a time sequence of the recent star formation history in I Zw 18, obtain an accurate C abundance, and delineate the stellar, neutral gas, and ionized gas distributions. Here we are proposing to add WFC2 narrow- band imaging at H Beta, O II Lambda3727, and S II Lambda6717,31 to combine with our cycle 4 narrow band imaging at H Alpha and O III Lambda5007 in order to map the reddening and ionization structure of the ionized gas and to search for enhanced collisional excitation due to shocks. These new observations will be invaluable to our goal of producing a detailed photoionization model of the high surface brightness knots of I Zw 18 to ensure the most reliable chemical abundance determinations possible. We also propose to obtain an FOS spectrum of the SE component in order to derive a C abundance measurement. We will compare this with the C/O and C/N abundance ratios observed in the NE component. The C abundance in I Zw 18 is key to determining whether there are trends of increasing C/O and C/N with increasing O/H in dwarf star forming galaxies.
No associations
LandOfFree
I zw 18: Building a Model 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 I zw 18: Building a Model, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and I zw 18: Building a Model will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1117809