ISO SWS Observations of H II Regions in NGC 6822 and I ZW 36: Sulfur Abundances and Temperature Fluctuations

Details ISO SWS Observations of H II Regions in NGC 6822 and I ZW 36: Sulfur Abundances and Temperature Fluctuations ISO SWS Observations of H II Regions in NGC 6822 and I ZW 36: Sulfur Abundances and Temperature Fluctuations

2002-09-04

arxiv.org/abs/astro-ph/0209084v1

Astrophys.J. 581 (2002) 1002-1012

Astronomy and Astrophysics

Astrophysics

32 Pages total, including 6 encapsulated postscript figures (one with two parts). Accepted for Publication in the 20 Dec 2002

Scientific paper

10.1086/344299

We report ISO SWS infrared spectroscopy of the H II region Hubble V in NGC 6822 and the blue compact dwarf galaxy I Zw 36. Observations of Br alpha, [S III] at 18.7 and 33.5 microns, and [S IV] at 10.5 microns are used to determine ionic sulfur abundances in these H II regions. There is relatively good agreement between our observations and predictions of S^+3 abundances based on photoionization calculations, although there is an offset in the sense that the models overpredict the S^+3 abundances. We emphasize a need for more observations of this type in order to place nebular sulfur abundance determinations on firmer ground. The S/O ratios derived using the ISO observations in combination with optical data are consistent with values of S/O, derived from optical measurements of other metal-poor galaxies. We present a new formalism for the simultaneous determination of the temperature, temperature fluctuations, and abundances in a nebula, given a mix of optical and infrared observed line ratios. The uncertainties in our ISO measurements and the lack of observations of [S III] lambda 9532 or lambda 9069 do not allow an accurate determination of the amplitude of temperature fluctuations for Hubble V and I Zw 36. Finally, using synthetic data, we illustrate the diagnostic power and limitations of our new method.

Affiliated with

Also associated with

No associations

Rating

ISO SWS Observations of H II Regions in NGC 6822 and I ZW 36: Sulfur Abundances and Temperature Fluctuations 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 ISO SWS Observations of H II Regions in NGC 6822 and I ZW 36: Sulfur Abundances and Temperature Fluctuations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and ISO SWS Observations of H II Regions in NGC 6822 and I ZW 36: Sulfur Abundances and Temperature Fluctuations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-620172