Chandra Large and Very Large Projects

Proposal Number: 02910585

Title: CHANDRA SURVEY OF THE GALACTIC RIDGE AROUND THE MILKY WAY CENTER

PI Name: Q. Daniel Wang

We propose an X-ray survey of a 2.4x0.7 square deg field around the Galactic center, using a set of Chandra ACIS pointings. With the unprecedented spatial and spectral resolutions as well as the broad energy coverage, this survey will provide an invaluable database for studying X-ray pulsars, binaries, supernova remnants, and superbubbles as well as many unique features observed in the field. The resultant exquisite X-ray images, complemented by an existing large-scale ROSAT PSPC mapping in soft X-ray, will allow for direct comparison with similar maps in radio and infrared. In particular, the survey will provide an excellent opportunity to determine the origin of the well-known Galactic ridge X-ray emission.

Proposal Number: 06910168

Title: Massive Star Life, Death, and Rebirth in the Perseus Arm

PI Name: Leisa Townsley

This joint Chandra/XMM mosaic of W4/W3/HB3 allows us to chronicle the X-ray output of the entire life cycle of high-mass stars, from their intrinsic and wind-collision emission, through their SN phase, and back to the embedded, protostellar X-rays heralding the next generation of massive star formation. In addition we see the feedback of these massive stars on the interstellar medium in the Perseus Arm: the stellar winds from a massive young cluster (IC 1805) have blown the W4 superbubble and chimney; perhaps an older superbubble is over 100 times brighter in X-rays due to supernovae in its interior (HB3), and the expansion of these bubbles is compressing the W3 molecular cloud and triggering a new generation of stars to form.

Proposal Number: 07910613

Title: A Legacy Study of Stellar Life Cycles at the Galactic Center

PI Name: Michael Muno

We propose a set of 27 40 ks Chandra observations of the central 300x80 pc of the Galaxy, as part of a multiwavelength project to study stellar life cycles in the region. Our observations will increase the number of accreting compact objects detected there by a factor of 10, to 12,000. This sample will: (1) increase the known number of HMXBs with IR counterparts several-fold, providing stringent tests of population synthesis models, (2) provide spectral and timing data on a new class of faint X-ray transients, (3) identify the sites of recent star formation by detecting their X-ray luminous WR/O stars, (4) identify elusive young pulsars near the Galactic Center, and (5) constrain the physics of particle acceleration in the mysterious radio filaments.

Proposal Number: 09910161

Title: The Great Nebula in Carina: Protoplanetary Disks to Starburst Galaxies

PI Name: Leisa Townsley

The Great Nebula in Carina is a superb site to study the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We propose to map the Carina star-forming complex with a mosaic of 20 new 60-ks ACIS-I pointings as a testbed for understanding recent and ongoing star formation and to probe its regions of bright diffuse X-ray emission. We will provide a catalog of multiwavelength properties of ~12,000 X-ray-selected stars. We will explore superbubble confinement, shocks, cloud evaporation, mass-loading of winds, ISM enrichment, and HII region energetics. We will also examine Carina as a surrogate environment for our Solar System's formation, where protoplanetary disks are bathed in harsh winds and radiation from nearby massive stars.

Proposal Number: 09910246

Title: THE ORIGIN OF THE GALACTIC RIDGE X-RAY EMISSION

PI Name: Mikhail Revnivtsev

We propose a very deep (900 ksec) observation of a carefully selected patch of the Galaxy. This observation will provide the most direct and unambiguous answer to the 30-year-old puzzle of the nature of the Galactic "diffuse" X-ray emission. Recent studies comparing the luminosity function of X-ray sources in the Solar neighborhood with the number-flux distributions toward the Galactic Center and plane strongly suggest that the GRXE can be explained by the integrated emission of millions of faint stellar sources - CVs and coronally active stars. The surface density of them is expected to exceed 1 per 60sq.sec in the proposed observation, in sharp contrast to the expectation in the diffuse model. Clearly, Chandra is the only mission in the foreseeable future which can solve this problem.