Chandra Large and Very Large Projects

Proposal Number: 08300134

Title: Testing the Physics of Magnetic Accretion: EX Hydrae from the Shock to the White Dwarf Surface

PI Name: Nancy Brickhouse

We propose to observe the magnetic Cataclysmic Variable (CV) EX Hydrae with the HETG to make a direct measurement of the temperature and density structure of its accretion columns and study the physics of the shock and subsequent cooling flow. The accretion column structure, crucial to our understanding of accretion physics, remains one of the last unexplored components of CVs and other accreting objects. The accretion columns of EX Hydrae are unobscured and are periodically occulted by the body of the white dwarf, making it the ideal target for this study. We will use high signal-to-noise light curves for individual spectral lines to measure the temperature and density structure. The result will be applicable to a broad range of objects from clusters of galaxies to T Tauri stars.

Proposal Number: 09300101

Title: A Chandra Legacy Survey of Dynamically Active Globular Clusters

PI Name: David Pooley

From our experience with Chandra, we have determined an empirical, successful, and model-independent method for determining the the neutron-star low-mass X-ray binary (LMXB) content and bright cataclysmic variable (CV) of a globular cluster (GC) in a reasonably short ACIS exposure. We propose a program that will discover ~30 LMXBs and ~150 CVs in 31 GCs. When combined with other observations, we will have direct knowledge of over 90% of the total LMXB population in GCs. We will accurately determine the role of GC dynamics in the formation of both LMXBs and CVs. We will also obtain an estimate for the density of the LMXBs and CVs in the field. This study will have important implications both for theories of LMXB and CV formation and for theories of GC dynamics and evolution.