Craig Alan Gullixson

The stellar component of the Galaxy as seen by the AFGL infrared sky survey

Les magnitudes du programme dobservations IR du ciel AFGL ont ete evaluees par comparaison directe avec des observations terrestres. On en deduit de nouvelles versions du catalogue AFGL. On rapporte les observations IR de tous les objets stellaires observes a 11,20 ou 27 μm et on donne un echantillon statistique des etoiles vues seulement a 4 μm. Lanalyse des observations conduit a des estimations des magnitudes absolues a 4 μm et 10 μm et des densites spatiales des deux classes dobjets

The H II regions of IC 1613

New H-alpha images are presented of IC 1613, a small irregular galaxy in the Local Group. The images, obtained with a CCD on the 42-in telescope at Lowell Observatory, have been calibrated and used to produce an H-alpha luminosity function and a size distribution for the H II regions in IC 1613. The results are compared to results for NGC 6822 and the Magellanic Clouds. The size distribution is found to be Poissonian over a limited range. 24 refs.

Optical and infrared surface photometry of NGC 3077

Photoelectric U, B, and V, photovoltaic K, and four-filter CCD surface photometry of the small, M81-linked Irr II galaxy NGC 3077 are reported. The observations are compared with data from previous studies, and the mass, density, and optical depth ratios are determined for a prominent dust cloud near the center of the galaxy. These characteristics are found to be similar to those of galactic dust clouds associated with star-formation sites. The observed intensity distribution at various wavelengths indicates that NGC 3077 was an elliptical galaxy before its interaction with M81. During the interaction NGC 3077 acquired the interstellar material which is currently forming stars in its central regions. 46 references.

High-resolution H and K mapping of W51

The H-II region W51 has been mapped in the near-infrared H and K wavebands with a resolution of about 6 arcsec over an area of about 14 sq arcsec. The W51 IRS 1 source has been resolved into six components, and an arc-like extension of small H-II regions is found that seems to parallel the edge of the molecular cloud. Measurements of the fluxes and extinctions of these sources are presented. A close correspondence is noted between the present K maps and the radio maps of Scott (1978). 22 refs.