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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.

Proposal Number: 09500471

Title: A Deep Chandra Observation of G54.1+0.3

PI Name: Patrick Slane

Chandra observations of pulsar wind nebulae have revolutionized our understanding of these systems, revealing a wide variety of complex structures that all relate to the basic conversion of spin-down power to an axisymmetric wind with collimated outflows. Based on initial observations, G54.1+0.3 displays Doppler-brightened emission from the wind termination shock region, large-scale jets that form the elongated structure of the nebula, and faint emission that hints at a possible torus as well as large-scale filamentary structure. We propose a Chandra Large Project to obtain deep observations of G54.1+0.3 in order to resolve these structures, study their spectra, and derive properties related to flow conditions and the magnetic field structure of the nebula.

Proposal Number: 09620513

Title: Galaxies across the Octaves: A Chandra Legacy Survey of SINGS Galaxies

PI Name: Leigh Jenkins

We propose to complete a rich, X-ray unbiased, multiwavelength Legacy dataset for a sample of 40 nearby galaxies. These galaxies are a distance limited (d < 10 Mpc) sample from the Spitzer Infrared Nearby Galaxy Survey (SINGS) Legacy program. The sample is now 45% complete. Our observations will detect X-ray binaries as faint as 3e36-1e37 erg/s, allowing us to constrain the X-ray binary/SFR correlation over a large range of galaxy properties and build X-ray binary Luminosity Functions for galaxies across a range of star formation histories. We will produce Legacy datasets and source catalogs for the community, and run theoretical binary population synthesis models in support of this effort.

Proposal Number: 09800310

Title: Probing Dark Energy with Relaxed Galaxy Clusters

PI Name: Steven Allen

We seek to constrain dark energy using studies of the apparent evolution of the X-ray gas mass fraction in the most X-ray luminous, dynamically relaxed galaxy clusters. The proposed observations will improve the detection of the effects of dark energy from the X-ray data alone to > 5 sigma. More importantly, they will allow us to measure the level of intrinsic (systematic) scatter in distance measurements from this technique and establish whether this is smaller than from type Ia supernovae measurements. Used in combination with supernovae and CMB data, the new Chandra observations will allow the most precise search to date for evolution in the dark energy equation of state - our best approach in trying to understand the origin of cosmic acceleration.

Proposal Number: 09800847

Title: BOW SHOCK, ELECTRON-ION EQUILIBRIUM, BREAKUP OF COOL CORE, AND DARK SUBCLUSTER IN ABELL 520

PI Name: Maxim Markevitch

Shock fronts provide a unique tool to study the cluster plasma. Only two have been found, those in 1E0657 and A520. Using a long observation of 1E0657, we have determined, for the first time in any astrophysical plasma, that electron-proton equilibration time is shorter than Coulomb - a tantalizing result but based on one object. A520 gives the only chance to confirm it. Its shock also coincides with an edge of the radio halo, enabling tests of the origin of the intracluster relativistic electrons. A520 also exhibits a remnant of a cool core broken up by merger-induced instabilities, providing data on plasma viscosity. Finally, weak lensing map of A520 reveals an intriguing dark subcluster almost devoid of galaxies. We propose a long observation of this exceptionally interesting cluster.

Proposal Number: 09900660

Title: The Evolution of Faint AGN at High Redshift

PI Name: Kirpal Nandra

We propose a very deep (total 800ks/field) Chandra survey of 0.25 deg2 covering 3 contiguous fields in the Extended Groth Strip, which have exceptional multiwaveband coverage obtained by the AEGIS project. These data, in combination with the CDF North and South, will provide a definitive measurement of the evolution of faint, X-ray selected AGN from z=3-4, where the optical number counts start to drop dramatically. In combination with ultradeep Spitzer data in the same region, this survey will also provide a crucial step forward towards a more complete census of AGN activity and the importance of Compton thick AGN at high z, with associated implications for the total accretion budget of the universe.

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.

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The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email:   cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2025. All rights reserved.