| Proposal Number | Subject Category | PI Name | Title |
|---|---|---|---|
| 07100246 | SOLAR SYSTEM | Vasili Kharchenko | Spectra of the Charge-Exchange Mechanism for the Diffuse X-ray Background |
| 07200173 | STARS AND WD | Ming Gu | Theoretical Wavelengths of $n\to 2$ ($3 |
| 07200879 | STARS AND WD | Janos Zsargo | Implementation of Plasma Emission Calculations into A non-LTE Radiative Transfer Program |
| 07500095 | SN, SNR AND ISOLATED NS | Dong Lai | The Nature of Isolated, Thermally Emitting Neutron Stars |
| 07500920 | SN, SNR AND ISOLATED NS | George Pavlov | Radiative Transitions of Once-ionized Helium in Very Strong Magnetic Fields |
| 07620311 | NORMAL GALAXIES: X-RAY POPULATIONS | Krzysztof Belczynski | X-ray Luminosity Function Modeling for Starburst Galaxies |
| 07620626 | NORMAL GALAXIES: X-RAY POPULATIONS | John Fregeau | Dynamical Formation of X-ray Sources in Globular Clusters |
| 07700647 | ACTIVE GALAXIES AND QUASARS | Timothy Kallman | Combined Hydrodynamic and Spectrum Synthesis Modeling of Seyfert Torus Outflows |
| 07700774 | ACTIVE GALAXIES AND QUASARS | Markos Georganopoulos | A toolbox for modeling images and spectra of Chandra detected Radio Galaxy jets and their hotspots. |
| 07800390 | CLUSTERS OF GALAXIES | Scott Randall | Constraining the Self-Interaction Cross-Section of Dark Matter Using Simulations and Observations of E1 0657-56 |
Subject Category:SOLAR SYSTEM
Proposal Number: 07100246
Title:Spectra of the Charge-Exchange Mechanism for the Diffuse X-ray Background
PI Name: Vasili Kharchenko
We propose to construct spectra of X-ray emission induced by the Charge-Exchange (CX) collisions in the heliosphere and astrospheres. About 50% of intensity of the X-ray background below 1 keV is produced by the charge-exchange mechanism. We will investigate an influence of the CX emission on observations of cosmological objects. We will calculate X-ray and EUV emission spectra induced by the heavy solar (stellar) wind ions colliding with the neutral interstellar and geocoronal gas. CX cascading X-ray lines of highly charged Fe, Si, S, and Mg ions will be computed and together with previously calculated O, C, N, and Ne lines will be included in the synthetic CX spectra.
Subject Category:STARS AND WD
Proposal Number: 07200173
Title:Theoretical Wavelengths of $n\to 2$ ($3 PI Name: Ming Gu We propose to calculate the wavelengths of $n\to 2$ ($3 < n < 8$) transitions in L-shell ions of iron and nickel, using a newly developed, combined configuration interaction and many-body perturbation theory approach. This method has been used to calculate the $3\to 2$ transitions of the same ions, and proven to be able to reproduce wavelengths to within a few m{\AA}. The results of this project will be used to revise astrophysical plasma emission database line list. These new wavelengths will be important for modeling stellar coronal spectra.
Subject Category:STARS AND WD Proposal Number: 07200879 Title:Implementation of Plasma Emission Calculations into A non-LTE Radiative Transfer Program PI Name: Janos Zsargo We propose to combine an advanced plasma emission code (APEC) with a non-LTE stellar atmosphere code (CMFGEN) to provide model spectra for early-type stars. It will allow for combined spectral analysis of all observable wavelengths, and will simultaneously provide stellar parameters (effective temperature, abundances etc.), wind parameters (mass-loss rate, terminal velocity), and the distribution of the X-ray emitting plasma in the wind together with its temperatures and emission measures.
Subject Category:SN, SNR AND ISOLATED NS Proposal Number: 07500095 Title:The Nature of Isolated, Thermally Emitting Neutron Stars PI Name: Dong Lai In the last few years, there have been significant observations (e.g. by Chandra) devoted to the study of thermal radiation from isolated neutron stars (NSs). Of particular interest are the 6-7 NSs whose spectra appear to be entirely thermal. The nature of these objects remains unclear at present, mainly because their spectra (including lines) are not yet understood. We propose to study the atmospheres and the radiation spectra of strongly magnetized NSs. We will construct atmosphere models for different compositions (H, He, C and O) and magnetic field strengths, including the effects of vacuum polarization and bound atoms. We will produce synthetic spectra and lightcurves and confront our results with observational data.
Subject Category:SN, SNR AND ISOLATED NS Proposal Number: 07500920 Title:Radiative Transitions of Once-ionized Helium in Very Strong Magnetic Fields PI Name: George Pavlov Recent investigations have shown that the atmospheres of neutron stars (NSs) with very strong magnetic field are likely comprised of helium. To properly interpret the X-ray spectra from such NSs, including lines and photoionization edges, it is necessary to know the structure and radiative transitions of He ions in strong magnetic fields. We have calculated the bound states and strengths of bound-bound transitions of the He+ ion, including the nontrivial effects of the ion's motion. We propose to develop new codes, which will include the continuum and autoionizing states of He+, and calculate the radiative transitions involving such states. The results will be used for modeling helium atmospheres of NSs and interpretng the X-ray spectra of AXPs, SGRs, and radio-quiet isolated NSs.
Subject Category:NORMAL GALAXIES: X-RAY POPULATIONS Proposal Number: 07620311 Title:X-ray Luminosity Function Modeling for Starburst Galaxies PI Name: Krzysztof Belczynski We propose to undertake a systematic and comprehensive study of X-ray binary populations in starburst galaxies. The modeling will be performed with the state-of-art population synthesis code StarTrack. We will calculate a set of theoretical models representative of different starburst environments. The library of XLFs for different starburst masses, ages, initial conditions and evolutionary assumptions will be constructed. The synthetic functions could then be compared against Chandra observations of nearby starburst galaxies. Matching synthetic and observed XLFs will present a new diagnostic tool for the determination of age and physical conditions within a given starburst galaxy.
Subject Category:NORMAL GALAXIES: X-RAY POPULATIONS Proposal Number: 07620626 Title:Dynamical Formation of X-ray Sources in Globular Clusters PI Name: John Fregeau Bright LMXBs have been known to be overabundant in globular clusters (GCs) for 30 years, yet the details of X-ray binary formation in GCs are still not well understood. Chandra has yielded a wealth of data on low-luminosity X-ray populations (quiescent LMXBs, MSPs, active binaries, and most cataclysmic variables) in clusters, which has begun to demonstrate the importance of stellar dynamical interactions in their formation. We propose a theoretical research program combining a treatment of binary stellar evolution with GC dynamics to study the formation of X-ray sources in GCs. Comparing the predictions of our models with observations should aid in our understanding of Chandra data, and provide constraints on stellar evolutionary processes and GC initial conditions.
Subject Category:ACTIVE GALAXIES AND QUASARS Proposal Number: 07700647 Title:Combined Hydrodynamic and Spectrum Synthesis Modeling of Seyfert Torus Outflows PI Name: Timothy Kallman We propose to make detailed tests of models for X-ray spectra from Seyfert 1 warm absorber outflows in which the outflow arises from ~1 pc away from the nucleus. This is likely the site of the obscuring torus implied by unification models. We plan to calculate numerical hydrodynamic models for the flow,including radiation effects and synthetic spectra in order to test this scenario for the origin of X-ray absorbing gas. A model which describes the observed spectrum will provide insight into the mass flux in the flow, the driving mechanism, and can also have implications for our understanding of Seyfert unification and the effects of the flow on the environment.
Subject Category:ACTIVE GALAXIES AND QUASARS Proposal Number: 07700774 Title:A toolbox for modeling images and spectra of Chandra detected Radio Galaxy jets and their hotspots. PI Name: Markos Georganopoulos Chandra observations present us with strong arguments that the plasma flows in large scale powerful jets are substantially relativistic (Lorentz factors ~10-20) and gradually decelerating up to the hotspots, where in a collision with the intergalactic medium they become subrelativistic. We have developed the first, admittedly crude, emission models from relativistic decelerating flows that reproduce the observations of individual sources, as well as their collective behavior. Here we propose to advance these models to a more realistic physical description and make them publicly available. The models will be the only tools available to the community for mapping the jet velocity profile through fitting the broadband spectra and multiwavelenght maps of jets.
Subject Category:CLUSTERS OF GALAXIES Proposal Number: 07800390 Title:Constraining the Self-Interaction Cross-Section of Dark Matter Using Simulations and Observations of E1 0657-56 PI Name: Scott Randall We propose to constrain the self-interaction cross-section of dark matter, sigma, by comparing X-ray and weak-lensing observations of the galaxy cluster E1 0657-56 with results from simulations. Initial observations show that the subcluster gas core lags the dark matter clump indicating that the dark matter is not fluid-like. The unique geometry of this merger allows for three independent methods for estimating sigma. Analytic esitmates have previously been derived, but recent access to 0.5 Msec of Chandra data and a greatly improved mass map warrant a more detailed comparison with a numerical model. To this end, we propose to develop an N-body/hydrodynamical code, based on an existing code, that will be able to simultaneously handle gas dynamics and collisonal dark matter.
Subject Category: Proposal Number: Title: PI Name: Subject Category: Proposal Number: Title: PI Name:
