APS Research by Juan Cabanela

My research has focused on using the Minnesota Automated Plate Scanner's capability of mechanical data reduction of POSS I plates to investigate galaxies. I have investigated galaxy alignments and am currently looking into developing a better model for internal extinction in galaxies.

• Galaxy Properties from a Diameter-limited Catalog: My Ph.D. Thesis, this project involved the investigation of internal extinction in galaxies using (in part) a catalog of 217,768 galaxies pulled from the APS Catalog of the POSS I. This is a diameter-limited (at 10 arcseconds) catalog of galaxies on POSS I plates within 30 degrees of the North Galactic Pole (NGP).
• MAPS-NGP Catalog: The MAPS-NGP catalog is my catalog of 217,768 galaxies in the 1/12 of the sky around of North Galactic Pole. An electronic version can be freely downloaded from my Ph.D. homepage.
• Galaxy Alignments in the Pisces-Perseus Supercluster - Revisited (with Greg Aldering): This project was an investigation into the possibility of various kinds of galaxy alignments in the Pisces-Perseus Supercluster using images from 1400 galaxies. The results indicate a possibility that weak alignments of a three sorts may be present.
• MAPS-PP Catalog: The electronic version of my catalog of 1400 galaxies in the Pisces-Perseus Supercluster with accurately measured position angles and ellipticities is now available online.
• Over a Quarter Million Galaxies at the North Galactic Pole (with Roberta Humphreys): This is the WWW version of the poster paper we presented at the Summer 1998 AAS Meeting (in San Diego, CA). We have shown that biases in previous galaxy catalogs have led to an erroneous determination that galaxies are 'optically thick'. We have used the APS galaxy diameters for ZCAT galaxies in the NGP region to show that in fact galaxies are at least somewhat optically thin. While not a surprising result, we believe we have resolved some rather serious problems with previous determinations of the internal extinction of galaxies.