# Accepted Cycle 11 Archive Proposals

Proposal NumberSubject CategoryPI NameTitle
11200516ARCHIVEVinay KashyapMany Flares Make A Corona
11200826ARCHIVEJanos ZsargoMulti-wavelength Study of Early-type Stars Observed with Chandra HETGS
11300182ARCHIVEPatrick GodonAn Archival X-Ray Spectroscopic Sutdy of the July 2001 Giant Outburst of WZ Sge
11400342ARCHIVEJulia LeeA comprehensive archival study of GRS~1915 HETGS spectra: variability studies and line-of-sight dust properties
11400427ARCHIVELI JITHE PHYSICAL PROPERTIES OF ACCRETION DISK CORONA
11500086ARCHIVEFrederick SewardChandra Supernova Remnant Catalog Update
11500147ARCHIVEFeryal OzelAn Archival Study of Supernova Remnants
11500270ARCHIVESANGWOOK PARKProbing Metallicity of the Large Magellanic Cloud Using Supernova Remnants
11500327ARCHIVELaura LopezDissecting Supernova Remnants Observed with Chandra
11500842ARCHIVEKnox LongThe Luminous Supernova Remnant in NGC4449: Charting the Future for SN 1987A
11610544ARCHIVEZhiyuan LiDecomposing M81's X-ray emission: nucleus, stars and hot gas
11620758ARCHIVERupali ChandarThe Nature of Optical Counterparts to X-ray Binaries in M101
11700109ARCHIVESmita MathurOutflows and Feedback: An Archival Study
11700268ARCHIVERobert GibsonThe X-Ray View of Stripe 82 Quasars: Variability-Based Surveys and Science
11800591ARCHIVEBradford BensonStudying Cluster Physics to the Virial Radius with Combined X-ray and Sunyav-Zel'dovich Measurements
11800734ARCHIVEAndisheh MahdaviCorrection of Hydrostatic Cluster Masses through Power Ratios and Weak Lensing
11800867ARCHIVESimona GiacintucciWhat are those clusters that do not have a radio halo?
11900274ARCHIVEPaul GreenGalaxy Environments vs. X-ray Activity in the ChaMP/SDSS
11900843ARCHIVEGeorge ChartasAN ARCHIVAL STUDY OF THE X-RAY SPECTRAL EVOLUTION OF AGNs
11910670ARCHIVEMaxim MarkevitchSEARCH FOR UNIDENTIFIED EMISSION LINES IN STACKED SPECTRA OF GALAXY CLUSTERS AND THE GALACTIC CENTER

Subject Category: STARS AND WD

Proposal Number: 11200516

Title: Many Flares Make A Corona

PI Name: Vinay Kashyap

We propose to carry out a comprehensive analysis of the archived data of active stars to determine the flare properties of their coronae. We plan to analyze long duration observations of strong coronal sources; i.e., all stars that have been observed with a grating in place. We will focus on deriving the form of the number distributions of flare energies on active stars, which have tended to have power-laws with indices greater than 2, in contrast to the solar case, where the power-law index is often measured to be 1.8 . Such a study will be invaluable to compare with models of flare initiation and energy release. We will also carry out more traditional timing analysis studies on the light curves, and explore spectral-temporal variability.

Subject Category: STARS AND WD

Proposal Number: 11200826

Title: Multi-wavelength Study of Early-type Stars Observed with Chandra HETGS

PI Name: Janos Zsargo

We propose a joint study of X-ray, UV, and optical spectra of a sample of early-type supergiants, giants, and dwarfs. The analysis will be done with XCMFGEN, which combines a modern X-ray plasma emission code (APEC/APED) with a widely used stellar atmosphere code (CMFGEN). Fundamental stellar and wind parameters such as Teff, wind velocity law, radially-dependent clumping factor, and elemental abundances will be obtained by analyzing archival IUE/HST and optical data. The spatial and temperature distribution of X-ray emitting regions will be constrained by both UV and X-ray observables. The X-ray line profiles are also sensitive probes of absorption by the wind, and together with UV and optical lines they will be used to constrain mass-loss rates.

Subject Category: WD BINARIES AND CV

Proposal Number: 11300182

Title: An Archival X-Ray Spectroscopic Sutdy of the July 2001 Giant Outburst of WZ Sge

PI Name: Patrick Godon

WZ Sge, the most extreme dwarf nova, underwent a superoutburst in July 2001. Unprecedented multi-wavelength coverage was carried out with HST, FUSE, Chandra and ground-based telescopes, providing a unique opportunity to study this extraordinary gigantic accretion event. We fully analyzed and published our FUSE and HST observations during outburst, decline and cooling phases. However, to our amazement, the high quality LETGS and ACS Chandra data obtained by others during this extraordinary outburst event were not analyzed or published (except for a short preliminary conference paper, 2001). We propose to fully investigate the new science hidden in the Chandra dataset as related to new develpments in the boundary layer theory and the information contained in the QPOs and DNOs of dwarf nova.

Subject Category: BH AND NS BINARIES

Proposal Number: 11400342

Title: A comprehensive archival study of GRS~1915 HETGS spectra: variability studies and line-of-sight dust properties

PI Name: Julia Lee

We propose archival research for all existing Chandra HETGS observations of GRS 1915+105 (11 over the Chandra lifetime) to conduct a comprehensive and exhaustive spectral and imaging study of all available data to realize three science goals.(1) Through detailed spectral variability studies, we endeavor to better understand the physical origins for GRS~1915+105 behavior: wind dynamics, and the observed sensitive interplay between jet and accretion disk-wind. In complement with laboratory experiments of likely ISM dust candidates, and X-ray scattering halo studies, we will determine (2) the quantity, composition, and (3) distribution of dust along the GRS 1915+105 line-of-sight.

Subject Category: BH AND NS BINARIES

Proposal Number: 11400427

Title: THE PHYSICAL PROPERTIES OF ACCRETION DISK CORONA

PI Name: LI JI

We propose to investigate the physical properties of Accretion Disk Corona sources (ADCs) via application of our accretion disk atmosphere and corona model to archived {\it Chandra} HETG observations of ADCs. Our aim is to characterize the structure of the accretion disk atmosphere in terms of accretion rate, scale height, temperature, density, and ionization distribution. By executing the model in parallel under ISIS, we will not only be able to fit the spectra, but we will explore far more of the complex parameter space than would be possible with other tools.

Subject Category: SN, SNR AND ISOLATED NS

Proposal Number: 11500086

Title: Chandra Supernova Remnant Catalog Update

PI Name: Frederick Seward

We seek funds to hire a person to repair and update our web-based catalog of Chandra supernova remnant observations. We have found this quite useful for general-knowledge browsing and for proposal preparation. It is also used by a number of organizations. Eliminating the PI's computer, search engines, and selecting one remnant (so a catalog visit counts as 1) we record about 50-100 hits/month. But after 5 years of use, environment updates and other improvements have broken some of the scripts. Some information is hard to retrieve and catalog updates are now done by hand. There are also research possibilities which could be enhanced. We need someone to concentrate on this for 3-6 months, fix the scripts, and incorporate new material.

Subject Category: SN, SNR AND ISOLATED NS

Proposal Number: 11500147

Title: An Archival Study of Supernova Remnants

PI Name: Feryal Ozel

The Chandra X-ray Observatory has enabled an active and comprehensive program of research on supernova remnants (SNRs) since its launch. Ten years' worth of Chandra observations of SNRs generated an invaluable database for the study of global properties of SNRs. We propose a comprehensive, comparative, and uniform study of SNRs in order to address two particular questions: What is the distribution of hydrogen column densities towards supernova remnants? and How well can supernova remnants, given the spatial variations within them, be modeled with existing thermal emission models? Our study will ultimately lead to a better determination of the relationship between the hydrogen column density and optical extinction, thus the gas-to-dust ratio, in the Galaxy.

Subject Category: SN, SNR AND ISOLATED NS

Proposal Number: 11500270

Title: Probing Metallicity of the Large Magellanic Cloud Using Supernova Remnants

PI Name: SANGWOOK PARK

Accurate measurements of interstellar composition is essential to study star-formation/nucleosynthetic history and evolution of galaxies. The Large Magellanic Cloud (LMC) is an excellent candidate for the ISM study due to its proximity and a low foreground absorption. X-ray spectroscopy of supernova remnants (SNRs) is an effective tool to measure ISM abundances, which is independent and complementary to traditional optical/UV spectroscopy of stars. Previous X-ray measurements of the LMC abundances using the ASCA data are a decade-old. The excellent imaging/spectroscopic capability of Chandra ACIS should provide a significantly more accurate and reliable measurement of the LMC abundances. Thus, we propose an archival study of 17 LMC SNRs to measure the ISM abundances of the LMC.

Subject Category: SN, SNR AND ISOLATED NS

Proposal Number: 11500327

Title: Dissecting Supernova Remnants Observed with Chandra

PI Name: Laura Lopez

Chandra has observed over one-hundred supernova remnants (SNRs) in the Milky Way, yet no systematic analysis has been conducted to compare the X-ray properties of these complex and diverse sources. Toward this end, we propose an archival study of eighteen galactic SNRs. We will apply three well-established methods to these datasets: a power-ratio method to probe morphological symmetry, two-point correlation to measure chemical segregation and distribution, and wavelet-transform analysis to quantify sub-structure. Our sources reflect SNRs of all types and a variety of ages, and detailed comparison between them will provide crucial insights regarding the nature of explosions, the effects of heating and dense environments, and particle acceleration properties.

Subject Category: SN, SNR AND ISOLATED NS

Proposal Number: 11500842

Title: The Luminous Supernova Remnant in NGC4449: Charting the Future for SN 1987A

PI Name: Knox Long

The X-ray luminosity and the optical spectrum of the extraordinary young SNR in NGC4449 have changed since it was discovered in 1978. In Cycle 10 we were awarded 75 ks for a second-epoch Chandra ACIS S spectrum, and one night on the MMT for an optical spectrum of the SNR. Comparison of X-ray and optical spectra from different epochs will lead to a more complete understanding of how the shock from this 50-100 year old SN is overrunning the circumstellar medium of the progenitor, and help us predict its future evolution and to compare this to the expected future of SN 1987A. Our optical observations in Jan 2009 were completely lost to weather. The intent of this archival proposal is to give us a second chance at an optical spectrum that will be crucial for interpreting the Chandra data.

Subject Category: NORMAL GALAXIES: DIFFUSE EMISSION

Proposal Number: 11610544

Title: Decomposing M81's X-ray emission: nucleus, stars and hot gas

PI Name: Zhiyuan Li

We propose to study the overall X-ray emission of M81, in particular for the first time the diffuse emission from hot gas, with more than 30 existing observations. Specifically and step-by-step, we will 1) constrain the X-ray variability of the nucleus, 2) construct luminosity functions down to $L_{0.3-8 keV}\sim 8\times10^{35} {\rm~ergs~s^{-1}}$ for both the LMXBs and HMXBs, 3) isolate the truly diffuse X-ray emission from the collective emission of unresovled stellar objects, and 4) characterize and model the hot gas, both spatially and spectrally. The results will represent a unique galaxy-wide decomposition of the X-ray emission and an important step toward understanding the roles of stellar and nuclear feedback in galaxy evolution.

Subject Category: NORMAL GALAXIES: X-RAY POPULATIONS

Proposal Number: 11620758

Title: The Nature of Optical Counterparts to X-ray Binaries in M101

PI Name: Rupali Chandar

The x-ray emission from nearby spiral galaxies is dominated by low and high mass x-ray binaries. We still have little detailed information on these binary systems, such as their ages and where they form within galaxies. One of the most promising avenues for addressing these issues is to identify and study properties of the optical counterparts to x-ray binaries. This is best accomplished via a comparison of CHANDRA observations in the x-ray with high resolution optical imaging taken with the Hubble Space Telescope (HST). We propose a detailed investigation of the optical counterparts to x-ray binaries in M101, which has some of the highest quality CHANDRA and HST data available, yet no systematic study of optical counterparts, in order to determine the properties of these systems.

Subject Category: ACTIVE GALAXIES AND QUASARS

Proposal Number: 11700109

Title: Outflows and Feedback: An Archival Study

PI Name: Smita Mathur

In the past ten years we have made significant progress in understanding the physical conditions in AGN outflows, now allowing us to ask important astrophysical questions. Our proposal has two components: (1) self consistent analysis of grating data of a sample of AGN with X-ray outflows and (2) zeroth order CCD spectroscopy to measure variability timescales of absorbers. This will break the degeneracy between absorber density and radial distance. With this novel technique we will better understand AGN outflows, their relation to the accretion process and fundamental AGN properties such as black hole mass and Eddington luminosity ratio; measure mass, energy and momentum transport and their relevance to the feedback process; and compare these observational results with theoretical models.

Subject Category: ACTIVE GALAXIES AND QUASARS

Proposal Number: 11700268

Title: The X-Ray View of Stripe 82 Quasars: Variability-Based Surveys and Science

PI Name: Robert Gibson

We propose to use the Chandra archive and source catalog to conduct a large-scale X-ray study of SDSS Stripe 82 quasars. We will obtain and calibrate a multi-color, variability-based quasar survey; compare optical/UV variability selection metrics; and perform a systematic study of the selection efficiencies, biases, and contaminants of both multi- and single-epoch quasar identification strategies. We will conduct a new study of near-simultaneous optical/UV and X-ray properties for Chandra sources observed from 2005 2008, and will also test recent hypotheses about AGN accretion and structure. This study will provide a baseline for X-ray studies involving upcoming, large-scale optical variability surveys such as Pan-STARRS and the LSST.

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 11800591

Title: Studying Cluster Physics to the Virial Radius with Combined X-ray and Sunyav-Zel'dovich Measurements

PI Name: Bradford Benson

We propose to use archival Chandra data to do a joint X-ray and Sunyaev-Zel'dovich effect (SZ) analysis for a set of 15 clusters also observed by the South Pole Telescope (SPT). This data set will measure the properties of the intracluster medium (ICM) out to very large radii because of the unprecedented sensitivity of the SPT and the very deep X-ray observations available form the Chandra archive. Our joint X-ray and SZ analysis will target three main science goals at radii reaching and exceeding the virial radius: 1) determining temperature and pressure profiles, 2) measuring gas fractions versus radius in search of missing baryons, and 3) measuring SZ, X-ray, and mass scaling relations.

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 11800734

Title: Correction of Hydrostatic Cluster Masses through Power Ratios and Weak Lensing

PI Name: Andisheh Mahdavi

The evolution of rich, X-ray emitting clusters of galaxies has given us precise measurements of the cosmological parameters, with dramatic constraints on the dark energy equation of state. Built into these measurements are wholesale corrections for the infamous "X-ray mass underestimate"---the fact that X-ray masses are systematically low due to the incomplete thermalization of the intracluster plasma. We seek to refine the mass correction for cosmological use through morphological power ratios. Power ratios deliver more accurate correction factors because they take into account variations in substructure from cluster to cluster. We will test their ability to correct X-ray masses by comparing hydrostatic and weak lensing mass profiles for a sample of 44 rich clusters of galaxies.

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 11800867

Title: What are those clusters that do not have a radio halo?

PI Name: Simona Giacintucci

We propose to analyze Chandra archival data on approximately 30 X-ray luminous clusters between z=0.2-0.4 that constitute our GMRT radio halo survey. We will perform a systematic, uniform and quantitative study of their dynamical state based on X-ray morphology and temperature maps. Our aim is to determine why some clusters have powerful radio halos at 1.4 GHz and some don't, with few if any in the intermediate state. Are all clusters that lack the high-frequency radio halos relaxed? Those of them that will show signs of minor mergers, will be followed up with GMRT at lower frequencies. This study will provide an important validation of the currently favored turbulent re-acceleration model for the radio halo formation.

Subject Category: EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 11900274

Title: Galaxy Environments vs. X-ray Activity in the ChaMP/SDSS

PI Name: Paul Green

We propose a large archival study of the clustering and environment of SDSS galaxies as a function of X-ray properties across 323 fields characterized by the Chandra Multiwavelength Project (ChaMP). We will measure the two-point correlation function and bias between X-ray AGN and galaxies on scales from 0.1 - 20 Mpc. ChaMP's unprecedented statistics for small-scale clustering are critical for understanding mechanisms of triggering and fueling. Stacking will provide new and unbiased constraints on the dependence of Lx on local density, independent of optical AGN classification or even X-ray detection status. Large ChaMP/SDSS samples subdivided by galaxy redshift, absolute magnitude, and color will quantify the relationships between star formation, accretion, and environment.

Subject Category: EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 11900843

Title: AN ARCHIVAL STUDY OF THE X-RAY SPECTRAL EVOLUTION OF AGNs

PI Name: George Chartas

We recently found evidence for a possible redshift dependent correlation of the X-ray spectral slope of radio-quiet AGNs at z > 0.1 with X-ray luminosity. We propose to analyze additional archived deep-field Chandra observations in order to achieve the following scientific goals: (a) Significantly increase the sample size in order to place tighter constraints on the significance of the Gamma vs. L_X correlation over a broader range of luminosities. (b) Minimize the effects of cosmic variance and selection effects on our results (c) Test the Gamma vs. L_X relation separately for type I and II AGNs. (d) Test the correlation in narrower redshift bands and thus better constrain the epoch at which possible changes in the average emission properties of AGN occurred.

Subject Category: GALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 11910670

Title: SEARCH FOR UNIDENTIFIED EMISSION LINES IN STACKED SPECTRA OF GALAXY CLUSTERS AND THE GALACTIC CENTER

PI Name: Maxim Markevitch

We propose to stack the spectra of all bright galaxy clusters observed with Chandra, and look for unidentified emission lines in the combined spectrum. We will also combine deep Chandra observations of low-extinction windows toward the Galactic Center. These observations cover the densest peaks of the dark matter distribution, and may reveal an X-ray signature of the sterile neutrino - one of the attractive dark mater candidates. Our secondary goal is to look for untabulated emission lines from the intracluster plasma, such as the recently discovered Cr line. By stacking the spectra of sources at different redshifts in the emitter frame, we will eliminate most detector and background systematics that preclude convincing detections of faint unidentified features in any single object.

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