Vivian U

Vivian U

Postdoctoral Scholar
Department of Physics and Astronomy
University of California, Riverside
900 University Avenue
Riverside, CA 92521

Office: Pierce 2219A
Email: vivianu-at-ucr.edu

Research interests: Infrared Galaxies, Interacting Galaxies, Active Galactic Nuclei, Starburst-AGN Connection, Galaxy Formation and Evolution, Integral-field Spectroscopy with Adaptive Optics, Submillimeter/Radio Astronomy

Biographical Information

  • Postdoc, UC Riverside (2012-Present)
  • Ph.D. in Astronomy, IfA, University of Hawai'i at Manoa (2012)
    • NASA Harriett G. Jenkins Predoctoral Fellow (2009-2012)
    • SAO Predoctoral Fellow, Harvard-Smithsonian CfA (2009-2011)
  • B.S. in Astrophysics, Caltech (2006)

Publications and Curriculum Vitae

You can search for my publications on ADS and arXiv! And here is my CV in pdf format.


I am a postdoc in the Department of Physics and Astronomy at UC Riverside working with Dr. Bahram Mobasher. As part of the Science Team for the InfraRed Multi-object Spectrograph (IRMS) on the Thirty-Meter Telescope (TMT), we are developing the exposure time calculator (ETC) to quantify the sensitivity of the instrument as aided by NFIRAOS, the adaptive optics systems on the TMT, in order to optimize its design parameters.

  • Check out the IRMS webpage!
  • Try out the preliminary ETC for IRMS here! (Start from the README file in the tarball; contact me if you have any questions.)

I completed my PhD in astronomy at the University of Hawaii's Institute for Astronomy under the supervision of Dr. David Sanders (IfA) and Dr. Giovanni Fazio (CfA). My dissertation research was a study of the luminous infrared galaxies (LIRGs) in the local universe: global properties, nuclear activity, and the starburst-AGN connection. The sample of (U)LIRGs originates from the Great Observatories All-sky LIRG Survey (GOALS). Global spectral energy distributions (SEDs) have been constructed using uniform photometry extracted with common aperture masks, enabling derivation of physical properties such as infrared luminosities and stellar masses as a whole. A basic understanding of the global properties of the local (U)LIRGs prompt detailed investigations on the physical processes associated with nuclear energetic activity. I have undertaken a high-resolution observing campaign using Keck's near-infrared integral-field spectrograph with adaptive optics and the Submillimeter Array to study gas and stellar morphology and kinematics in the nuclei of these infrared-luminous galaxy mergers. Through general surveys and specific case studies of NGC 6240 and Mrk 273, I have demonstrated the value of high-resolution near-infrared and submillimeter observations in disentangling the physical conditions at the heart of (U)LIRGs. My selected GOALS- and dissertation-related publications and relevant proceedings are listed below:

  • Medling, A.; U, Vivian; et al. "Stellar and Gaseous Nuclear Disks Observed in Nearby (U)LIRGs." 2014, ApJ, 784, 70
  • U, Vivian et al. "The Inner Kiloparsec of Mrk 273 with Keck Adaptive Optics." 2013, ApJ, 775, 115
  • Stierwalt, S. et al. "Mid-infrared Properties of Nearby Luminous Infrared Galaxies. I. Spitzer Infrared Spectrograph Spectra for the GOALS Sample." 2013, ApJS, 206, 1
  • Wang, J. et al. "Fast and Furious: Shock Heated Gas as the Origin of Spatially Resolved Hard X-ray Emission in the Central 5 kpc of the Galaxy Merger NGC 6240." 2013, ApJ, in review, arXiv:1303.2980
  • U, Vivian et al. "Spectral Energy Distribution of Local Luminous and Ultraluminous Infrared Galaxies." 2012, ApJS, 203, 9
  • Tan, Q.; Gao, Y.; Wang, Z.; U, Vivian. "High-resolution SMA imaging of (ultra)-luminous infrared galaxies." 2012, IAUS, 284, 471
  • Mazzarella, J. et al. "Investigation of Dual Active Nuclei, Outflows, Shock-heated Gas, and Young Star Clusters in Markarian 266." 2012, AJ, 144, 125
  • U, Vivian et al. "High-resolution Mapping of CO(3-2) in NGC 6240." 2011, ASPC, 446, 97
  • Iwasawa, K.; Sanders, D. B.; Teng, S. H.; U, Vivian; et al. "C-GOALS: Chandra observations of a complete sample of luminous infrared galaxies from the IRAS Revised Bright Galaxy Survey." 2011 A&A, 529, 106
  • U, Vivian et al. "Spectral Energy Distributions of LIRGs." 2010, IAUS, 267, 143
  • Sanders, D. B.; Kartaltepe, J. S.; Kewley, L. J.; U, Vivian; et al. "Luminous Infrared Galaxies and the Starburst-AGN Connection." 2009, ASPC, 408, 3

During my early grad school years, I worked with Dr. Rolf-Peter Kudritzki on a quantitative spectroscopy analysis of a population of blue supergiants in M33. We measured a distance to the galaxy with the flux-weighted gravity---luminosity relation method:

  • U, Vivian et al. "A New Distance to M33 Using Blue Supergiants and the FGLR Method." 2009, ApJ, 704, 1120

As an undergrad, I did my senior thesis with Dr. Richard Ellis and Dr. Lauren MacArthur at Caltech on spiral bulges with 0.1<z<1.2 in the GOODS field. My very first summer research experience (e.g. SURF) with Dr. Chris Conselice on distant Extremely Red Objects had secured my interests in extragalactic research ever since my early college years!

  • MacArthur, L. A.; Ellis, R. S.; Treu, T.; U, Vivian et al. "The Evolutionary History of Galactic Bulges: Photometric and Spectroscopic Studies of Distant Spheroids in the GOODS Fields." 2008, ApJ, 680, 70
  • Conselice, C. J.; Bundy, K.; U, Vivian et al. "The faint and extremely red K-band selected galaxy population in the DEEP2/Palomar fields." 2008, MNRAS, 383, 1366

Page maintained by Vivian U: vivianu-at-ucr.edu

Last modified: Fri Nov 9 12:32:35 PST 2012