Chandra X-Ray Observatory
	(CXC)

Cycle 5 Accepted Theory Proposals

Subject CategoryPI Name Title
NORMAL STARS AND WDJoseph CassinelliClumpy Outflows from Hot Stars and Their X-ray Signatures
SN, SNR AND ISOLATED NSDong Lai Surface Emission from Magnetized Neutron Stars
SN, SNR AND ISOLATED NS ROGER CHEVALIERThe X-Ray Emission from Type Ib and Ic Supernovae
SN, SNR AND ISOLATED NSRandall Smith Calculating Non-equilibrium Collisional Emission for Chandra
SN, SNR AND ISOLATED NS Jonathan Arons DISTRIBUTED PARTICLE ACCELERATION AND THE X-RAY SURFACE BRIGHTNESS OF PULSAR WIND NEBULAE
ACTIVE GALAXIES AND QUASARS Masao Sako Line Acceleration of Outflows and the Radiative Force Multiplier
CLUSTERS OF GALAXIES Christopher Reynolds Simulations of radio-galaxy/intracluster-medium interactions including thermal conduction
CLUSTERS OF GALAXIES August EvrardA Virtual Cluster Exploratory Year Two: Mock Observations of Simulated Galaxy Clusters

Subject Category: NORMAL STARS AND WD

Title: Clumpy Outflows from Hot Stars and Their X-ray Signatures

PI Name: Joseph Cassinelli

Bow shocks around clumps in winds have properties that appear to be needed to explain the Chandra observations of hot stars. For the best example, tau Sco, infall appears to be needed to explain UV profiles. If the infall is in the form of clumps, the bow shocks are able to explain the hard X-rays seen, the presence of copius soft X-rays and the low source radii derived from FIR lines of Helium like ions. Needed for a broader discussion of the effects of clumps are hydrodynamical shock model calculations. We have the essential ingredients in a MHD code. The results will provide for a variety of wind and clump parameters of the X-ray flux distribution, which can be expressed in terms of source temperatures.


Subject Category: SN, SNR AND ISOLATED NS

Title: Surface Emission from Magnetized Neutron Stars

PI Name: Dong Lai

There has been significant observational progress in the last few years on the study of surface emission from isolated neutron stars (radio pulsars, radio-quiet neutron stars and magnetars). These observations can potentially tell us much about the interior and the near vicinity of neutron stars. We propose to theoretically study the surface layers and the radiation spectra of strongly magnetized neutron stars. We will construct atmsophere models for a wide range of magnetic field strengths and temperatures, including the effects of bound atoms and condensed matter, as well as the effect of vacuum polarization in superstrong magnetic fields. We will confront our theoretical models with CHANDRA observations, thereby advancing our knowledge of neutron star physics/astrophysics.


Subject Category: SN, SNR AND ISOLATED NS

Title: The X-Ray Emission from Type Ib and Ic Supernovae

PI Name: ROGER CHEVALIER

The X-ray emission from Type Ib and Ic supernovae, whose progenitors are massive stars lacking a hydrogen envelope, probably involves the interaction of the supernova with a circumstellar wind. Plausible mechanisms are thermal emission, synchrotron radiation, or inverse Compton scattering of photospheric photons. The expected radiation will be calculated in the context of hydrodynamic models for the interaction, including constraints from observed radio synchrotron emission and from models for the supernova light curves. The research will address questions of central engine vs. supernova driven interaction, the relation of X-ray luminosity to broad-lined Type Ic supernovae, and the possibility of interaction with the dense wind from a companion star to the supernova.


Subject Category: SN, SNR AND ISOLATED NS

Title: Calculating Non-equilibrium Collisional Emission for Chandra

PI Name: Randall Smith

Existing non-equilibrium ionization models for Chandra use outdated atomic rates, inflexible model assumptions, and inadequate spectral output. We propose to update existing collections of ionization and recombination rates with more recent calculations and measurements and put the data into freely-available electronic form. We will also create the basic tools needed to calculate an ionization balance either in or out of equilibrium. Users will also be able to calculate spectral models which can be directly compared to Chandra observations. By combining the ionization balance and the spectral calculation we ensure the result is self-consistent; by separating these from the physical model of the plasma we allow anyone to easily calculate the emission spectrum.


Subject Category: SN, SNR AND ISOLATED NS

Title: DISTRIBUTED PARTICLE ACCELERATION AND THE X-RAY SURFACE BRIGHTNESS OF PULSAR WIND NEBULAE

PI Name: Jonathan Arons

Theoretical investigation of problems of direct relevance to Chandra studies of Pulsar Wind Nebulae is proposed. The acceleration of electrons and positrons in the flow downstream of the termination shock in the magnetized relativistic wind will be calculated, using simple formulae for the acceleration rates. Models of spatially distributed acceleration will be contrasted to the particle spectra and surface brightness distributions that result from instantaneous acceleration at the pair shock. Particle-in-cell simulations will be used to investigate the fundamental physics of diffusive Fermi acceleration in relativistic shocks in electron-positron plasmas.


Subject Category: ACTIVE GALAXIES AND QUASARS

Title: Line Acceleration of Outflows and the Radiative Force Multiplier

PI Name: Masao Sako

We propose to study the detailed theoretical properties of radiatively-driven winds from AGN with particular focus on outflows observed in broad absorption line QSO. We begin our investigation with a comprehensive set of atomic calculations that are necessary to accurately compute the radiative force multiplier under various physical conditions, which will be made available to the public. We will then construct dynamical radiative transfer models and investigate how these new calculations affect the dynamics of the flow. These modeling will provide new insight for interpreting the observed absorption troughs in BALQSO, the quantitative properties of their X-ray spectra, as well as the global physical picture of mass outflows in these systems.


Subject Category: CLUSTERS OF GALAXIES

Title: Simulations of radio-galaxy/intracluster-medium interactions including thermal conduction

PI Name: Christopher Reynolds

Recent Chandra and XMM-Newton observations of galaxy clusters have highlighted the importance that a central radio-galaxy might have on the energetics and evolution of its host's intracluster medium (ICM). Concurrently, several theorists have raised the importance of thermal conduction with the ICM. We propose to perform a series of hydrodynamical simulations to investigate radio-galaxy heating of the ICM in the presence of thermal conduction. We will compare our simulation results to the latest Chandra datasets, paying particular attention to the radial run of temperature and entropy, as well as ICM mixing/overturning that might upset observed metallicity gradients. These will be some of the most complete simulations of ICM/radio-galaxy interactions to date.


Subject Category: CLUSTERS OF GALAXIES

Title: A Virtual Cluster Exploratory Year Two: Mock Observations of Simulated Galaxy Clusters

PI Name: August Evrard

We propose continuing development of a prototype Virtual Cluster Exploratory (VCE) toolkit that will enable analysis of simulated cluster ensembles by the research community. A client-side model consisting of IDL routines and a searchable web archive is being assembled, with functional design based on input from observers. Along with custom mock Chandra observations, users can explore additional observables (e.g., total mass/SZ maps) as well the full 3D structure and merger histories of simulated clusters. We seek to enhance VCE in the following areas: i) support for non-Chandra response functions; ii) extensions to the simulated model archive and iii) dynamic creation of random sky patches. The toolkit will help accelerate convergence to a complete physical description of the ICM.

Smithsonian Institute Smithsonian Institute

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