Short-Term H-alpha Variability in M Dwarfs (2009)
Lee, Khee-Gan, Berger, Edo, Knapp, Gillian R.
We study the variability of H-alpha emission in mid- to late-M dwarfs on timescales of ~ 0.1-1 hr as a proxy for magnetic activity. We spectroscopically observed 43 active dwarfs with spectral types...
Relativistic reflection X-ray spectra of accretion disks (2009)
Lee, Khee-Gan, Wu, Kinwah, Fuerst, Steven V., Branduardi-Raymont, Graziella, Crowley, Oliver
We have calculated the relativistic reflection component of the X-ray spectra of accretion disks in active galactic nuclei (AGN). Our calculations have shown that the spectra can be significantly...
Constraining Extended Reionization Models Through Arcminute-Scale CMB Measurements (2009)
The measurement of the optical depth to free electrons, tau_r, in the cosmic microwave background (CMB) provides an important constraint on reionization, but is degenerate to more complex...
The Topology of Cosmological Reionization (2007)
Lee, Khee-Gan, Cen, Renyue, Gott III, J. Richard, Trac, Hy
Using the largest cosmological reionization simulation to-date (~24 billion particles), we use the genus curve to quantify the topology of neutral hydrogen distribution on scales > 1 Mpc as it...