------------------------- Summer research projects: ------------------------- [Andromeda, Milky Way, and nearby galaxy-related research projects are described below. The Andromeda data were collected by our team, the SPLASH collaboration (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo). The Andromeda and Milky Way data were obtained using the Keck telescope in Hawaii (world's largest optical telescope) and the powerful DEIMOS spectrograph.] -------------------------------------------------------------------- 1. Study motion of stars within Andromeda dwarf satellite galaxies Student: Claudia Kelley (Castilleja School) Mentor: Raja GuhaThakurta (UCSC faculty) Will also be working with: Claire Dorman & Kirsten Howley (UCSC PhD students) Erik Tollerud (UC Irvine PhD student) Use IDL spectral display / analysis software "zspec" (developed at UC Berkeley, modified by former UCSC PhD student Marla Geha) on spectra of stars seen in the direction of dwarf galaxy satellites of Andromeda. Identify different types of objects: stars in Andromeda's dwarf satellites, free floating stars in Andromeda's halo, foreground Milky Way stars, and distant galaxies in the background of Andromeda. Measure orbital speed of the satellite around Andromeda and the rate at which stars are rattling around within the satellite (related to its dark matter content). -------------------------------------------------------------------- 2. Analysis of the motion of stars in the Andromeda galaxy Student: Annie Cardinal (Castilleja School) Mentor: Kirsten Howley (UCSC PhD student) Will also be working with: Raja GuhaThakurta (UCSC faculty) Claire Dorman (UCSC PhD student) Carry out maximum likelihood fit to 3D data: x, y, velocity. Goal is to separate two structural subcomponents: bulge versus disk. Determine the rotation speed and velocity dispersion of each component, and measure bulge to disk ratio. This is the most direct way to make such a measurement but the necessary data have never been available before in Andromeda or in any other galaxy. -------------------------------------------------------------------- 3. Spectroscopic campaign to study the motion of stars in the disk of the Andromeda galaxy Student: Sara Holston (Castilleja School) Mentor: Raja GuhaThakurta (UCSC faculty) Will also be working with: Claire Dorman & Kirsten Howley (UCSC PhD students) Jason Kalirai (Space Telescope Science Institute staff) Another project somewhat related to project #2 above is to prepare for an extensive spectroscopic campaign, using the Keck telescope and DEIMOS spectrograph, on the hitherto uncharted eastern quadrant of Andromeda's disk. The preparations include point-spread-function fitting to determine brightnesses and positions of stars, finding relatively isolated stars based on the use of existing software and visual inspection, and designing DEIMOS multislit masks using existing software. The Keck/DEIMOS observations are expected to be conducted in the fall, sometime in the mid-August to mid-November time frame. ********** POSTPONED DUE TO UNAVAILABILITY OF STUDENT ********** -------------------------------------------------------------------- 4. Determining the chemical properties and physical conditions of stars from spectra Student: Michelle Deng (Harker School) Mentor: Claire Dorman (UCSC PhD student) Will also be working with: Raja GuhaThakurta (UCSC faculty) Evan Kirby (Caltech postdoc) Using the chi^2 technique, compare spectra of Andromeda stars (about which we know very little) to spectra of well studied stars in the Milky Way. Measure the iron to hydrogen ratio, [Fe/H], and the temperature of the star's outer layer (T_eff). Correlate the [Fe/H] values measured from the spectrum with another, independent measure of [Fe/H]. -------------------------------------------------------------------- 5. Calcium and magnesium content of Milky Way stars Student: Benjamin Chen (Harker School) Mentor: Evan Kirby (Caltech postdoc) Will also be working with: Raja GuhaThakurta (UCSC faculty) Use IDL spectral analysis tool "espec" (developed by former UCSC PhD student Evan Kirby) to measure the strengths of specific Mg and Ca absorption features in the spectra of Milky Way stars. Study trends in these Mg and Ca strengths as a function of [Fe/H] and T_eff (see description of project #3 above for the meaning of these terms). -------------------------------------------------------------------- 6. Comparing state-of-the-art computer simulations of a forming galaxy to the Andromeda galaxy Student: Anirudh Suvarna (Monte Vista High School) Mentor: Val Rashkov (UCSC PhD student) Will also be working with: Raja GuhaThakurta & Piero Madau (UCSC faculty) Use a C++ routine to construct a 2D projection of the "star particles" from the Via Lactea computer simulation of the formation of a dark matter and stellar halo (the disk of a large spiral galaxy typically resides inside such a halo). Draw random samples of such "stars" in a way that mimics the SPLASH collaboration's observations of the Andromeda galaxy. Compare the surface brightness distribution, kinematics, and substructure of these simulated "stars" to real stars in Andromeda. -------------------------------------------------------------------- 7. Demographics of dwarf elliptical galaxies in the Sloan Digital Sky Survey database Student: Jenny Hong (Palo Alto High School) Mentor: Raja GuhaThakurta (UCSC faculty) Will also be working with: Marla Geha (Yale University faculty) Connie Rockosi (UCSC faculty) Identify galaxies in the extensive Sloan Digital Sky Survey (SDSS) database whose properties are similar to those of dwarf elliptical galaxies - i.e. those with low luminosity, low surface brightness, and a smooth light distribution. Study the properties of these galaxies - specifically their colors and the presence / absence of emission lines - as a function of the density of the galaxy's environment. Use web browser based SQL queries to access the SDSS database. -------------------------------------------------------------------- 8. Quantifying the false positive rate in the search for red giant stars in the sparse outer halo of the Andromeda galaxy Student: Teresa Krause (Castilleja School) Mentor: Raja GuhaThakurta (UCSC faculty) Will also be working with: Karrie Gilbert (University of Washington postdoc) Marla Geha (Yale University faculty) Several lines of sight through the Milky Way galaxy have been probed using Keck/DEIMOS spectroscopy in order to study newly discovered dwarf satellite galaxies. Once members of these satellites have been eliminated using position and velocity criteria, the rest of the sample should consist of field stars in the Milky Way. Measure the likelihood statistic, L = log_10(P_giant/_Pdwarf), for each star using the Gilbert et al. (2006) method. Will need to adjust the details of the radial velocity diagnostic (PDF) by using the Besancon model for each Milky Way line of sight. For this *control* Milky Way-only sample, quantify any tail in the likelihood distribution to positive values. Analyze the distribution of L values along a few key lines of sight through the Andromeda galaxy. --------------------------------------------------------------------