KPNO REU Students at the 217th AAS Meeting (January 2011)

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.

[142.27] Investigating The AGN Population In Cluster Environments Across Different Wavelengths

Eleanor Byler (Wellesley College), D. Norman (NOAO)

Currently, there is no complete picture of AGN formation and evolution in galaxy clusters. A general understanding of the AGN population has been impeded by cluster and selection biases and recent studies have shown that there is a large population of obscured or optically unremarkable AGN in galaxy clusters. We used SDSS data to look at the AGN distribution in 12 clusters over a range of redshifts (z = 0.16 - 0.35) and compared the optical and X-ray AGN content with that of six “blank” fields. We found that on average the cluster fields had a small optical AGN excess as compared to blank fields. The AGN population and distribution was also compared by cluster morphology, and non-virialized clusters were found to have a higher X-ray and optical AGN content than virialized clusters. We also compare our optical AGN to Gilmour et al.‚Äôs (2009) X-ray survey to compare assumptions made about cluster membership.

[140.15] Parameterizing and Modeling Eclipsing Binaries in The Kepler Field Using Kepler Quarter 2 and 3 Data

Sean Morrison (Appalachian State University), K. Mighell (NOAO), S. Howell (NOAO), D. Bradstreet (Eastern University)

We present a preliminary analysis of Quarter 2 and Quarter 3 Kepler light curves for 56 eclipsing binary star systems from the Kepler Cycle 1 program 08-KEPLER08-0014, “A Calibration Study of Variable Stars in the Kepler Field” (PI: Mighell). We developed a C program to phase these long cadence (30 minute) data that determines the period and zero point with a typical precision of 0.0864 seconds for an orbital period of 1.019949 days. We have developed 3D models of the systems using Binary Maker 3 (BM3) by David Bradstreet. Spectra of 32 of the systems were obtained at the Kitt Peak National Observatory 2.1 m telescope using the GoldCam spectrometer. We have determined temperatures for some of the stars from the temperature ratios, based on the BM3 models, and the average temperatures for the spectral classifications of the stars which were derived from the 2.1-m spectra. The high photometric precision of the Kepler light curves allows us to identify significant star spots on a subset of the systems.

[242.14] The CNO Bi-cycle in the Open Cluster NGC 752

Keith Hawkins (Ohio University), S. Schuler (NOAO), J. King (Clemson University), L. The (Clemson University)

The CNO bi-cycle is the primary energy source for main sequence stars more massive than the sun. To test our understanding of stellar evolution models using the CNO bi-cycle, we have undertaken light-element (CNO) abundance analysis of three main sequence dwarf stars and three red giant stars in the open cluster NGC 752 utilizing high resolution (R ~ 50,000) spectroscopy from the Keck Observatory. Preliminary results indicate, as expected, there is a depletion of carbon in the giants relative to the dwarfs. Additional analysis is needed to determine if the amount of depletion is in line with model predictions, as seen in the Hyades open cluster. Oxygen abundances are derived from the high-excitation O I triplet, and there is a 0.19 dex offset in the [O/H] abundances between the giants and dwarfs which may be explained by non-local thermodynamic equilibrium (NLTE), although further analysis is needed to verify this. The standard procedure for spectroscopically determining stellar parameters used here allows for a measurement of the cluster metallicity, [Fe/H] = 0.04 ± 0.02. In addition to the Fe abundances we have determined Na, Mg, and Al abundances to determine the status of other nucleosynthesis processes. The Na, Mg and Al abundances of the giants are enhanced relative to the dwarfs, which is consistent with similar findings in giants of other open clusters.

[242.10] A Photometric Survey of Ori OB1b

Allison T. Merritt (University of California, Berkeley), W. Sherry (NOAO/NSO)

Several mechanisms have been suggested to describe the formation of sub-stellar mass objects (SSMOs), specifically brown dwarfs. Each proposed mechanism predicts a unique spatial distribution of the brown dwarfs relative to the O and B stars of the association. We have 9 square degrees of optical (VRI) data and 7 square degrees of NIR (JHK) data of Orion OB1b. The purpose of the survey is to obtain the photometric data that will allow us to determine the spatial distribution of brown dwarfs in this region and constrain the various formation theories. We present an overview of the survey, with an emphasis on the NIR data, as well as color-magnitude diagrams.

[334.11] The Extreme Red: Characterizing LSST’s Y3 and Y4 Filters

Michelle Kislak (University of California, Berkeley), C. Claver (NOAO), V. Krabbendam (NOAO), T. Axelrod (University of Arizona)

One of the essential science requirements of the Large Synoptic Survey Telescope lies in its high standard for photometric precision for both photometry and photometric redshift calculation. To capture rest-frame optical spectral features in high-redshift sources, the survey will use a variant of the Y band, which encompasses the reddest hundred nanometers before the Silicon response function cut-off. However, a significant data calibration challenge presents itself with this region of wavelength space: a strongly varying water absorption feature is present directly in the midst of it. In light of this, the survey has proposed two versions of the Y filter, a broad Y4 that includes the water band and a narrower Y3 that excludes it. In an effort to determine whether the wider filter is characterizable, we undertook an observing campaign with a 4k x 4k ccd camera on the 1.2m Calypso telescope on Kitt Peak to directly compare the properties of the two filters. We present preliminary analysis of this data and the conclusions that can be made from it.

[349.07] Effects Of Light Pollution On The Movements Of Leptonycteris Curasoae Yerbabuenae In The Tucson Area

Daniel Barringer (Union College), C. Walker (NOAO)

We used data from the GLOBE at Night project and telemetry tracking data of lesser long-nosed bats obtained by the Arizona Game and Fish Department to study the effects of light pollution on the flight paths of the bats between their day roosts and night foraging areas around the city of Tucson, AZ. With the visual limiting magnitude data from GLOBE at Night, we ran a compositional analysis with respect to the bats‚Äô flight paths to determine whether the bats were selecting for or against flight through regions of particular night sky brightness levels. We found that the bats selected for the regions in which the limiting sky magnitudes fell between the ranges of 2.8-3.0 to 3.6-3.8 and 4.4-4.6 to 5.0-5.2, suggesting that the lesser long-nosed bat can tolerate a fair degree of urbanization. We also compared this result to contour maps created with digital Sky Quality Meter data. In this presentation, we present the results from our compositional analysis with respect to the habits of the lesser long-nosed bat. For more information, please visit www.globeatnight.org.