| | |
| | |
Stat |
Members: 3645 Articles: 2'501'711 Articles rated: 2609
20 April 2024 |
|
| | | |
|
Article overview
| |
|
I ZW 18 -- a New Wolf-Rayet Galaxy | Yuri I. Izotov
; Craig B. Foltz
; Richard F. Green
; Natalia G. Guseva
; Trinh X. Thuan
; | Date: |
24 Jul 1997 | Subject: | astro-ph | Affiliation: | Main Astronomical Observatory, Ukraine), Craig B. Foltz (Multiple Mirror Telescope Observatory), Richard F. Green (National Optical Astronomy Observatories), Natalia G. Guseva (Main Astronomical Observatory, Ukraine) and Trinh X. Thuan (University of V | Abstract: | We report the discovery of broad Wolf-Rayet emission lines in the Multiple Mirror Telescope (MMT) spectrum of the NW component of I Zw 18, the lowest-metallicity blue compact dwarf (BCD) galaxy known. Two broad Wolf-Rayet (W-R) bumps at the wavelengths $lambda$4650 and $lambda$5800 are detected indicating the presence of WN and WC stars. The total numbers of WN and WC stars inferred from the luminosities of the broad He II $lambda$4686 and C IV $lambda$5808 lines are equal to 17(+/-)4 and 5(+/-)2, respectively. The W-R to O stars number ratio is equal to about 0.02, in satisfactory agreement with the value predicted by massive stellar evolution models with enhanced mass loss rates. The WC stars in the northwest component of I Zw 18 can be responsible for the presence of the nebular He II $lambda$4686 emission line, however the observed intensity of this line is several times larger than model predictions, and other sources of ionizing radiation at wavelengths shorter than 228AA are necessary. | Source: | arXiv, astro-ph/9707272 | Services: | Forum | Review | PDF | Favorites |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
| News, job offers and information for researchers and scientists:
| |