I am 6th year graduate student at the Department of Astronomy at the University of Maryland and a part of the Laboratory for Millimeter-wave Astronomy. I work under the direction of Stuart Vogel, Sheila Kannappan, and Andrew Baker.
Morphological Evolution of Blue-Sequence E/S0s
Recent work has identified a population of low-to-intermediate mass field galaxies that are morphologically early type (E/S0s) but reside on the "blue-sequence" in color vs. stellar mass space, where spiral galaxies typically reside. While some of these galaxies must be younger merger remnants destined to fade onto the red sequence, many appear to be settled products of long-ago mergers. A subset of these "blue-sequence E/S0s" could be evolving towards late-type morphologies via disk regrowth, as predicted by current models of hierarchical galaxy evolution. (Kannappan, Guie, & Baker 2009)
For my thesis, I am looking at star formation and the cold gas content
of these blue-sequence E/S0s to determine whether they are in fact
evolving towards late-type morphologies. Using
the Green Bank Telescope, we
obtained HI spectra for blue- and red-sequence E/S0s and found a
significant difference in the atomic gas content between the two
populations (top right, from Wei et
al. 2009). Preliminary CARMA CO(1-0)
maps reveal disk-like rotation of molecular gas in the inner regions
of several of our blue-sequence E/S0s, which suggests that they may
have gas disks suitable for stellar disk regrowth (Wei et al., in prep.).
Current work includes the analysis of CARMA CO(1-0)
maps, Spitzer IRAC and MIPS images, and VLA HI maps.
L.H. Wei, S.J. Kannappan, S.N. Vogel, & A.J. Baker
2009, submitted to ApJ
Cold Gas in Blue-Sequence E/S0s: Galaxies in Transition
L.H. Wei, S.J. Kannappan, S.N. Vogel, & A.J. Baker
to appear in the Proceedings of the Galaxy Wars: Stellar Populations and Star Formation in Interacting Galaxies Conference
Cold Gas in Blue-Sequence E/S0s: Galaxies in Transition
L.H. Wei, S.J. Kannappan, S.N. Vogel, & A.J. Baker
poster for Galaxy Wars: Stellar Populations and Star Formation in Interacting Galaxies Conference
Galaxy Gas Fractions, Characteristic Mass Scales, and the RESOLVE Survey
S.J. Kannappan & L.H. Wei
In AIP Conference Proceedings 1035: The Evolution of Galaxies Through the Neutral Hydrogen Window, Eds. R. Minchin and E. Momjian, 163
CARMA And GBT Observations Of Cold Gas In Red- And Blue-Sequence E/S0 Galaxies
L.H. Wei, S.N. Vogel, S.J. Kannappan, & A.J. Baker
poster for AAS 211th Meeting, Jan 2008
Star Formation in UV-Selected Galaxies out to z~1
The strength of the extragalactic infrared background implies that a considerable amount of star formation at higher redshifts has occured behind a veil of dust, which absorbs much of the light from young O and B stars. We compare galaxies detected in the near- and far-UV by GALEX with a 1.2mm MAMBO dust emission map of the NTT Deep Field (NDF) to determine the total contributions to the far-IR/submillimeter background and the cosmic star formation rate density from UV-selected galaxies out to z~1. Though we cannot detect the galaxies individually because they are dust-point, we attempt to measure a statistical detection of the sample as a whole.
GALEX Observations of the NTT Deep Field
L.H. Wei, A.J. Baker, D. Lutz, M. Lehnert, S.N. Vogel, & F. Bertoldi
poster for AAS 207th Meeting, Jan 2006
CARMA Commissioning
Between 2006 and 2009, I did commissioning work for
the Combined Array for Research in
Millimeter-Wave Astronomy (CARMA). It involved mostly testing
bandpass calibration techniques for narrow-bands. Below are some
technical pages I made for commissioning tests, as well as a memo I
wrote with our results.
When the 62MHz band went bad...
Bandpass Calibration Tests
Noise bp test on May 13
L. Wei, D. Woody, P. Teuben, M. La Vigne, & S. Vogel
CARMA Memo #45