2 results
The Giant HII Region NGC 2363
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- By Rosa González-Delgado, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, Enrique Pérez, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, Guillermo Tenorio-Tagle, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, José M. Víchez, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, Elena Terlevich, Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ, UK, Roberto J. Terlevich, Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ, UK, Eduardo Telles, Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ, UK, José M. Rodríguez-Espinosa, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, Miguel Mas-Hesse, Laboratorio de Astrofísica Espacial y Física Fundamental (LAEFF), Apdo. 50727, 28080 Madrid, Spain, María Luisa García-Vargas, Depto. Física Teórica CIX, Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain, Ángeles I. Díaz, Depto. Física Teórica CIX, Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain, Jordi Cepa, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, Hector Castañeda, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
- G. Tenorio-Tagle, Instituto de Astrofísica de Canarias, Tenerife
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- Book:
- Violent Star Formation
- Published online:
- 10 November 2010
- Print publication:
- 22 September 1994, pp 117-122
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Summary
We present narrow-band Hα imaging and long-slit optical and near infrared spectroscopy of the giant HII region NGC 2363. We have found broad emission lines at 4686 Å and at 5810 Å attributed to WC stars at 6 arcsec to the East of the brightest core of the region. We confirm the existence of low-intensity broad components in Hα and [OIII] which extend some 500 pc. We have derived the physical conditions and chemical composition of the gas in 15 different zones in the region, and do not find significant variations in the abundances. The Paschen discontinuity has been found in emission. The Pa electron temperatures obtained are significantly smaller than those obtained from the [OIII] and [SIII] emission lines, indicating the presence of large temperature fluctuations.
Introduction
One of the targets of the GEFE programme is the giant HII region NGC 2363 located in the SW of the irregular galaxy NGC 2366. This is one of the largest extragalactic HII regions with high surface brightness. The object was observed in La Palma in narrow band Hα and long-slit spectrophotometry from [OII] λ3227 to [SIII] λ9532 at two positions, at the brighest core of the region (which we call knot A) and at 6 arcsec to the East (knot B).
Narrow-band images
The object was observed with the 1-m JKT telescope. We used a CCD with a spatial scale of 0.3 arcsec pixel−1.
The Prototype Starburst Galaxy NGC 7714: Physical Conditions of the Gas and the Stellar Populations
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- By Rosa González-Delgado, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, Enrique Pérez, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, María Luisa García-Vargas, Depto. Física Teórica CIX, Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain, Elena Terlevich, Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ, UK, Roberto J. Terlevich, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain, José M. Víchez, Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain
- G. Tenorio-Tagle, Instituto de Astrofísica de Canarias, Tenerife
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- Book:
- Violent Star Formation
- Published online:
- 10 November 2010
- Print publication:
- 22 September 1994, pp 139-144
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Summary
We present narrow-band Hα imaging and long-slit optical and near-infrared spectroscopy of the starburst galaxy NGC 7714. We have detected WR stars in the starburst region, which indicate an age for the burst of between 3 and 5 Myr. We have obtained the physical condition of the gas in the starburst region and in three HII regions. These have moderately low abundances, while the nucleus has half solar abundance, with an overabundance of N.
Introduction
A typical starburst galaxy can be defined as a spiral galaxy with a bright nucleus bluer than expected for its morphological type, which emits strong narrow emission lines similar to low-ionization HII region spectra, as a consecuence of the photoionization by the ultraviolet radiation of hot stars, with typical Hα luminosities ranging from 1040 to 1042 erg s−1. During this intense recent burst of star formation between 107 and 1010 M⊙ of massive stars are formed within a radius of a few hundred pc about its nucleus.
NGC 7714, the prototype of the starburst (henceforth SB) galaxies (Weedman et al, 1981) and classified as a SBb peculiar, is in interaction with the irregular galaxy NGC 7715. The X-ray luminosity (6 1040 erg s−1) is explained with about 104 supernova remmants in a volume of 280 pc radius (Weedman et al. 1981). The 6-cm radio map shows a weak double radio structure separated by about 1 arcsec at p.a = 30°.