1998 REU/PIA Projects
- Integrated Photometry of Globular Clusters in the LMC and M33 - Jomel Atienza-Rosel
- Identifying SNRs in the Magellanic Cloud Emission-line Survey - Amanda Jefferson
- The Multicolor Light Curve of SN 1997ej - Aaron Steffen
- Developing an All-Sky Monitor Camera System - Patrick Welti
Integrated Photometry of Globular Clusters in the LMC and M33
Jomel Atienza-Rosel - California State University, Los Angeles
This project focused on the integrated properties of the globular cluster systems in the bar of the Large Magellanic Cloud and in M33. The objective is to study the age-metallicity relation of the clusters in these galaxies, and investigate factors which may affect this relation. For this purpose the basic properties of the clusters, such as the mass and density distribution, are first determined to find similar clusters from both of the galaxies. We used a King-model fitting program to determine the parameters of several clusters in both the LMC and M33. These clusters will then be the focus of more detailed comparative studies to investigate the age-metallicity relation.
Identifying SNRs in the Magellanic Cloud Emission-line Survey
Amanda Jefferson - University of Maryland, College Park
The Magellanic Cloud Emission-line Survey (MCELS) is a survey of two of our nearest neighboring galaxies, found in the Local Group: the Large and Small Magellanic Clouds. Dr. Smith and his collaborators wish to study the properties, kinematics, and dynamics of the interstellar medium in these galaxies using [SII], [OIII], and H-alpha filters.
Working in this survey, my project included observations, data reduction, data analysis, and final image production. I contributed about 6 nights of observing on Cerro Tololo, reduced about 7 nights of data, and finally analyzed two particular regions of the LMC in which we anticipated finding supernova remnant candidates. Procedures to complete this final analysis task involved taking the ratios of [S II] to H-alpha images and looking for regions of relatively strong [S II] emission, which indicate shocked gases, and therefore can aid in identifying an evolved supernova remnants. Several supernova remnants, including one previously undiscovered remnant, were identified in this way in the two regions which were fully analyzed.
I performed UBVRI photometry on the Supernova (SN) 1997ej which was observed at the Cerro Tololo Inter-American Observatory (CTIO). SN 1997ej was located in the elliptical galaxy IC2060. The galaxy light profile was modeled and subsequently subtracted using a task in the Space Telescope Science Data Analysis System (STSDAS), which is a package in the IRAF reduction program. PSF photometry was then performed on the galaxy-subtracted images using DAOPHOT, a program created by Peter B. Stetson of the Dominion Astrophysical Observatory. Landolt standards taken on 9 photometric nights were used to calibrate local standard stars in the images. Photometry on 11 nights of non-photometric data was then performed using these local standards.
Results of this 10-week REU program project were discussed in two poster papers. One was presented at the University of Wisconsin - Eau Claire's Undergraduate Research Day. The other poster was presented at the June 1998 meeting of the American Astronomical Society --- (Steffan et al. 1998, BAAS, 192, #06.09). A paper will be written and submitted to an astronomical journal in the following months.
We put together a sky camera which, when used on moonless nights, will be helpful in detecting the presence of thin clouds and/or high cirrus. The camera consists of three parts: an image intensifier, a video camera, and a protection circuit. The protection circuit prevents the phosphor screen in the image intensifier from being damaged by excessive light. The video signal is converted into a digital image using a frame grabber card in a Windows PC. The camera images are fed into a pipeline system which takes many images, averages them, and then writes them out into a format ready to be included into a self-updating web page. When the system is completely finished, astronomers will be able to bring up this web page and have a automatically updated image of the sky outside.