KPNO REU Students at the 213th AAS Meeting (January 2009)

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 2008 summer students will attend the 213rd meeting of the American Astronomical Society (AAS) at Long Beach, California in January 2009.

The abstracts of the REU student posters are reproduced below.

[460.24] Site Characterization of El Peñón: The Site of the Large Synoptic Survey Telescope

Taylor S. Chonis (University of Nebraska-Lincoln Dept. of Physics and Astronomy) , C. F. Claver (NOAO), J. Sebag (NOAO)

El Peñón is located at the southwest end of the Cerro Pachón ridge in northern Chile. Since its selection as the LSST observatory site, detailed measurements of wind and atmospheric seeing have been conducted to help determine design and operating parameters. The wind measurements are made at 4 elevations (5, 12, 20, 30 meters) using ultrasonic 3-axis anemometers. The atmospheric seeing is monitored with a Differential Image Motion Monitor (DIMM). We have studied correlations in the wind speed and direction at the different elevations and with the atmospheric seeing. From the wind-elevation correlations, we find evidence for a surface turbulence layer up to a minimum of 12 meters above the local topography. Knowing where the boundary layer is will affect the overall height of telescope and the summit building. In examining the correlation of image quality from the DIMM with wind directions and speed, we found a surprising result: there appears to be a weak preference for better seeing when the wind is coming from the south, rather than from the northeast as expected. We also find that this correlation appears to be independent of wind speed below 30 meters. This information will be used in site design analysis along with performance modeling of the LSST. This research was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 3 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.

[414.03] Collinder 121: Analyzing It’s Pre-main Sequence Population

Matthew Henderson (NOAO), W. Sherry (NSO)

OB associations represent excellent opportunities to study the end products of stellar accretion. These diffuse groups of stars, whose lifespans are limited by the dispersive forces that scatter them as they move through the galaxy, are thought to be the structures in which the majority of all stars form. We present a VI photometric census of the regions surrounding some of the stars identified by de Zeeuw et al. (1999) to be part of Collinder 121 (CMa OB2). Orion OB1 includes a clustered population of low-mass, pre-main sequence stars present in the regions around the OB stars that define the group. This study demonstrates whether a clustered population of low-mass, PMS stars exists in CMa OB2 and determines if the spatial pattern observed in Orion can be extended to another OB association in the solar neighborhood.Matt Henderson’s research was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 3 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.

[442.12] Deep Photometry of the Open Cluster IC4651

Tiffany Meshkat (NOAO), C. Claver (NOAO), K. Mighell (NOAO)

We present a preliminary analysis of deep CCD photometry of the Galactic open star cluster IC 4651. We seek to identify the white dwarf cluster members in order to determine the age, distance, metallicity of the star cluster and to test stellar evolutionary theory. Claver observed IC 4651 at the CTIO 4-meter telescope in Chile on May 7 - 10, 1997. The star cluster was covered by four camera fields with small overlapping regions; one field was observed each night. Long and short exposures were obtained with U, B, V, and I filters in each field. Two of the nights were photometric with subarsecond seeing, and the remaining two nights were not photometric. Stellar photometry was obtained using the DAOPHOT procedure within IRAF data reduction and analysis system. Calibrated photometry in all 4 fields was obtained using IRAF’s PHOTCAL package with the DAOPHOT instrumental magnitudes and standard star fit files. We made calibrated color-magnitude diagrams and color-color diagrams in all four fields. The distance modulus was determined to be (m-M) = 10.015 magnitudes, making IC4651 approximately 1000 pc away. The V vs. V-I color-magnitude diagram of IC 4651 is bracketed by the 1.5 Gyr and 2.0 Gyr Yonsei-Yi isochrones. White dwarf candidates were determined by selecting stars near the cooling sequences for DA 0.5 and 0.9 solar-mass white dwarfs; several of these white dwarf candidates fit the cooling sequences within one standard deviation errorbars. Meshkat’s research was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 3 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.

[474.03] Analyzing the Effects of Scattered Light on Stellar Photometry

Ashley Stewart (University of Arkansas, Fayetteville), J. Glaspey (NOAO)

The CCD detectors that we use today are very good at converting most of the light gathered by a telescope into an electronic signal without adding much noise to the process. What this means for observers is that they are now only limited by the optical quality of the telescope in how well they can measure the brightness of faint sources. Our goal was to quantify the affect of the scattered light component of telescope images, usually dominated by the quality of primary mirror coating, using empirically derived models of stellar Point Spread Functions for ground based imagers. We analyzed archived MOSAIC data from the W-Project, which used the Blanco 4m telescope in Cerro Tololo, primarily because it covered the same fields over multiple years using the same telescope, instruments, filters, and exposure times. From this data set, we selected stars using Source Extractor and performed the photometry with the IRAF package DAOPHOT. This gave an estimate of the magnitudes and magnitude errors of the stars in the fields which could be compared for data taken before and after primary mirror re-aluminizing. Here, we will present the findings of our project and discuss what future work could be done to improve the quality of science obtained from ground based telescopes.Stewart’s research was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program, which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 3 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.

[443.02] Investigating Galaxy Merger Signatures with IGNITE

Matthew J. Zagursky (University of Maryland), J. M. Lotz (NOAO)

I present the software package IGNITE, the Interacting Galaxy Non-Interactive Tail Extractor. Its purpose is to locate tidal tails and quantify their morphological and photometric properties. I demonstrate the effective use of IGNITE on the case galaxy of NGC 2623 and report the photometric and morphological signatures of tidal tails in this galaxy. The future of the IGNITE package is a merge with other successful software packages aimed at quantifying merging galaxies to further enhance the accuracy of the quantitative measurements of morphologies and photometry profiles of merging galaxy candidates.

A Wavelet Time Series Analysis of Aperiodic Variable Stars in the Kepler Field

Timothy Arnold (The Ohio State University) , K. Mighell (NOAO), S. Howell (NOAO)

The variable sky offers insights into the physical mechanisms of astronomical objects and can be used as a useful tool for many other purposes like the determination of distance with standard candles. Periodic variables were the first to be classified, understood, and used. Many variable but aperiodic light curves are discarded or insufficiently analyzed because of the apparent uselessness of the information contained in these data. Many contemporary projects (e.g. the Large Synoptic Survey Telescope, PanSTARRS, the Kepler mission) aim to map the transient sky, and recently methods of time series analysis have become increasingly advanced. It would be advantageous to discover identifying information in the large number of variable but ostensibly aperiodic light curves. We use a wavelet analysis, based on a weighted projection of time series data on to basis functions, to analyze aperiodic variable stars in the Burrell-Optical-Kepler Survey (BOKS). Using the Weighted Wavelet Z-Transform detailed in Foster 1996, we find that variable but aperiodic stars in our sample offer few characteristic properties that would be useful for further classification. Arnold’s research was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 3 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.