KPNO REU Students at the 219th AAS Meeting (January 2012)
The opportunity to present the findings of their original research at the most important national meeting of US astronomy is arguably one of the most prized benefits enjoyed by KPNO REU students. All six of the 2010 summer students attended the 217rd meeting of the American Astronomical Society (AAS) at Seattle, Washington in January 2011.
The abstracts of the REU student posters are reproduced below.
[154.23] X-Ray Selected AGN in A Merging Cluster
Joanna M. Taylor (Indiana University), D. Norman (NOAO), I. Soechting (Oxford University), G. Coldwell (El Instituto de Ciencias Astronómicas)
We investigate the X-ray AGN population and evolution in the merging galaxy cluster DLSCL J0522.2-4820 discovered via weak gravitational lensing shear from the Deep Lens Survey (DLS). Since weak lensing shear is dependent only on mass, it does not introduce the biases that typical cluster selection methods do. This cluster is of particular interest due to both its extended multiple X-ray emission peaks and the large number of X-ray point sources identified in the field. We measured the redshifts of X-ray AGN as well as cluster galaxies in order to investigate the 3-dimensional distribution and possible clustering of AGN in galaxy clusters. Of the 125 objects in our sample, 54 are galaxies in the cluster; the cluster redshift is determined to be z=0.2997±0.0096. This agrees well with a previous value of z=0.296±0.001. We identified several broad line AGN at high redshift including a quasar pair at redshift z=1.8. Currently, we have found no X-ray point sources to be within the cluster.
[246.24] Star Formation and AGN Activity in Ultraluminous Infrared Galaxies at z > 1.15
Vivienne Baldassare (Hunter College), J. Kartaltepe (NOAO)
We studied active galactic nucleus (AGN) activity and star formation in a sample of ultraluminous infrared galaxies (ULIRGs) with 1.17 < z < 1.602 and LIR > 1011.5 Lsolar. ULIRGs get 52 luminous and their extreme infrared luminosities from the heating of dust by star formation and/or AGN. Studies done in the local universe have revealed that all local ULIRGs are mergers (Sanders & Mirabel 1996), and have proposed evolutionary schemes in which early merger stages are dominated by starbursts, intermediate merger stages are dominated by starburst-AGN composite objects, and late merger stages are dominated by AGN (Yuan et al. 2010). They have also shown that most ULIRGs with LIR > 1012.4-12.5 Lsolar appear AGN-like (Tran et al. 2001). We used near infrared spectroscopy in order to determine whether these trends extend to high redshift, utilizing the [NII]/H-alpha and [OIII]/H-beta line ratios to plot our objects on a BPT diagram which classifies them as star forming, AGN, or composite. We find that many of the objects in our sample show evidence of mergers or interactions, and that all objects in our sample with LIR >1012.5 Lsolar are AGN or composite objects.
[145.02] PhAst: A Flexible IDL Astronomical Image Viewer
Morgan Rehnberg (Beloit College), R. Crawford (Rincon Ranch Observatory), M. Trueblood (NOAO), K. Mighell (NOAO)
We present near-Earth asteroid data analyzed with PhAst, a new IDL astronomical image viewer based on the existing application ATV. PhAst opens, displays, and analyzes an arbitrary number of FITS images. Analysis packages include image calibration, photometry, and astrometry (provided through an interface with SExtractor, SCAMP, and missFITS). PhAst has been designed to generate reports for Minor Planet Center reporting. PhAst is cross platform (Linux/Mac OSX/Windows for image viewing and Linux/Mac OSX for image analysis) and can be downloaded from the following website at NOAO: http://www.noao.edu/staff/mighell/phast/.
[347.09] Alternative Mounting Systems for the Galileoscope
Christine Welling (Dickinson College), S. Pompea (NOAO)
The Galileoscope is a kit telescope produced for the International Year of Astronomy (IYA) in 2009. As an educational tool, it has been distributed across the world. In order to successfully observe with the Galileoscope, it must be steadied in some way. The preferred method for stabilizing the Galileoscope is to use a tripod. However, this is not always possible, and other stabilization methods are needed. Alternative systems were designed to be constructible worldwide, and cost less than $5 to build. Seventeen alternative mounting systems were built and tested. Comparisons were made based on price to build, ease of construction, ease of use, and whether the system would remain pointed.
[348.02] An Analysis of Known Variable Stars in the Kepler Field
Nicholas J. Jimenez (Alfred University), K. J. Mighell (NOAO)
Using the catalog of the All-Sky Automatic Survey (ASAS) variable stars in the Kepler analyzed Kepler light curves from quarters 0, 1, and 2 using the NASA Star and Exoplanet Database Field, we (NStED) periodogram service and determined periods and amplitudes for the 777 variables we could access. The ASAS periods agree very well to the periods determined from the Kepler data except for semiregular variables. This is due to roughly a week-long interval between ASAS observations. With a higher observing frequency, these stars are much better characterized. We investigated the quality of the NStED service period determinations by comparing periods of the ASAS binaries to the periods determined for them by Slawson et al. We determined that NStED determines eclipsing similar periods to Slawson et al. for well-defined eclipsing binaries with sharply peaked periodograms, but when the main peak of the periodogram is broad there is greater uncertainty in the measurements. We also present an analysis of red giants that exhibit solar-like oscillations from the data set of Hekker et al. and compare their amplitudes (as measured from the Kepler light curves) to the strongly variable red giants in the ASAS data set. We find that variable red giants must be quiet in order to sustain solar-like oscillations.
[141.04] Light Pollution Around Tucson, AZ And Its Effect On The Spatial Distribution Of Lesser Long-nosed Bats
Alisa Fersch (Wesleyan University), C. Walker (National Optical Astronomy Observatory)
Light pollution is a well-known problem for astronomers. It is also gaining attention as an ecological issue. The federally endangered Lesser Long-Nosed Bat (Leptonycteris cursoae) resides for part of the year near Tucson, Arizona. It is possible that this species tends to avoid light. Excess artificial light would therefore interfere with the bats’ flight patterns and foraging habits. In order to test this hypothesis, we quantified night sky brightness with data from the citizen-science campaign GLOBE at Night. Using direct measurements taken with a Sky Quality Meter (SQM), we created a contour map of the artificial night sky brightness around Tucson. When this map is compared to the approximate flight paths of the lesser long-nosed bat, we can see that the bats do appear to be avoiding the brightest area of Tucson. We also used logistic regression to analyze what combination of ecological variables (ecoregion, vegetation over, landform and light) best describes the observed spatial distribution of lesser long-nosed bats. Of the models that were tested, light alone was not a good predictor of the bat presence or absence. However, light in addition to vegetation and ecoregion was the best model. This information can be useful for making decisions about lighting codes in areas of the city that the bats tend to traverse. The contour map of light pollution in Tucson will be useful for both future astronomy and ecology studies and can also be used for public outreach about light pollution.