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.