LibraryAstronomy & Space Science
We examine the census of star-forming galaxies and their extinction properties at redshift z~2, when a large fraction of the stellar mass in the universe formed. We find a good agreement between the X-ray, radio, and de-reddened UV estimates of the average star formation rate (SFR) for our sample of z~2 galaxies ...
In 2005, Palla & Baraffe proposed that brown dwarfs and very low mass stars (less than 0.1 solar masses) may be unstable to radial oscillations during the pre-main-sequence deuterium burning phase. With associated oscillation periods of 1-4 hours, this potentially new class of pulsation offers unprecedented ...
Adaptive optics (AO) corrects distortions created by atmospheric turbulence and delivers diffraction-limited images on ground-based telescopes. The vastly improved spatial resolution and sensitivity has been utilized for studying everything from the magnetic fields of sunspots upto the internal dynamics of ...
For centuries, we have known that our dynamic universe is adorned by cosmic fireworks: energetic and ephemeral beacons of light from a single star that are a million (nova) to a billion (supernova) times brighter than our sun. However, it had been an age-old conundrum that the brightest nova is approximately 1000 ...
We present results from an adaptive optics survey conducted with the Palomar and Keck telescopes over 3 years, which measured the frequency of stellar and sub-stellar companions to Sun-like stars. The survey sample contains 266 stars in the 3-10000 million year age range at heliocentric distances between 8 and ...
Communication is frequently identified in the literature as a major factor impacting Information Technology (IT) project failure. The importance of communication is amplified in buyer - seller relationships through the long-term impact of project failures on the future business of IT vendors with their ...
The diversity of stellar death is revealed in the energy, velocity and geometry of the explosion debris ("ejecta''). Using multi-wavelength observations of gamma-ray burst (GRB) afterglows I show that GRBs, arising from the death of massive stars, are marked by relativistic, collimated ejecta ("jets'') with a wide ...
Young stars are surrounded by massive, rotating disks of dust and gas, which supply a reservoir of material that may be incorporated into planets or accreted onto the central star. In this dissertation, I use high angular resolution observations at a range of wavelengths to understand the structure, ubiquity, ...
This dissertation describes work performed at the Palomar Testbed Interferometer (PTI) during 1998-2002. Using PTI, we developed a method to measure stellar angular diameters in the 1-3 milli-arcsecond range with a precision of better than 5%. Such diameter measurements were used to measure the mass-radius ...
As late as 1995, the anticipated widespread population of primeval galaxies remained at large, lurking undetected at unknown redshifts, with undiscovered properties. We present results from our efforts to detect and characterize primeval galaxies by their signature high-redshift Lyman-alpha emission lines utilizing ...
