Búsqueda de objetos en emisión Halpha en la Nebulosa de Carina (NGC3372)

G.F. HÄGELE, R.H. BARBÁ, G.L. BOSCH & N.I. MORRELL

Cordoba

Congreso; X Reunion Regional Latinoamericana de Astronomía; 2001

International Astronomical Union

The Carina Nebula (NGC3372) is one of the richest and more complex H II regions of our Galaxy, available to observations using medium size telescopes. The region covers almost 10 squared degrees and hosts several open clusters. Trumpler 14, 16 and Collinder 228 are the youngest ones, containing tens of O stars, several WN and the peculiar LBV η Carinae. CCD images were obtained with the Curtis-Schmidt camera at Cerro Tololo Interamerican Observatory with broadband B, V, R and I filters and narrowband [O III] 5007Å, Hα, and [S II] 6730Å. The 2k×2k detector spreads over a 1.2×1.2 degrees area on the sky centered in η Carinae. Series of increasing time exposures were taken, in order to maximize the magnitude range of our data. We performed aperture photometry using IRAF's apphot and calculated magnitudes for more than 20000 objects (S/N above 10) in the field. We used the (R - Hα) colour index as our main selection criteria for identifying stars with intrinsic Hα emission. Objects that showed an R - Hα index larger than -7.4 were considered emission line object candidates. As aperture photometry is not very sensitive in identifying non-stellar unresolved sources, we selected only candidates which are identified on all the examined filters. We have tackled possible contamination by symbiotic stars or compact planetary nebulae by analysing the candidates distribution in the colour-colour and colour-magnitude diagramas. We have detected more than 200 objects with Hα excess in the observed region, a much larger sample than the 19 and 3 objects detected by Wackerling (1970, MNRAS 149, 405) and Schwartz et al. (1990, Astron J. 100, 793) respectively.