Chandra X-Ray Observatory
	(CXC)

Please note that the abstracts refer to the PROPOSED project - which is not necessarily identical to the approved project.
For accurate target information, please check the Observation Catalog.


Cycle 8 Accepted Archive Proposals

Proposal NumberSubject CategoryPI NameTitle
08200320STARS AND WD Peter Beiersdorfer Tabulation of L-shell and M-shell lines in the LETGS spectra of Cool Stars
08200572STARS AND WD David Cohen Constraining Wind Porosity and Mass-Loss Rates with X-ray Line-Profile Modeling of OB Stars
08200696STARS AND WD Scott Wolk An Archive of Chandra Observations of Regions of Star Formation - A renewal of ANCHORS
08500812SN, SNR AND ISOLATED NS Eric GotthelfPulsar Wind Nebula Generation: A Spin-down Power Threshold?
08610100NORMAL GALAXIES: DIFFUSE EMISSION David Strickland Understanding the Origin of Diffuse X-ray Emission in the Halos and Disks of Disk Galaxies
08610275NORMAL GALAXIES: DIFFUSE EMISSION Zhiyuan Li Decomposing the X-ray Emission from the M31 Bulge
08610295NORMAL GALAXIES: DIFFUSE EMISSION Steven Allen The relation between accretion rate and jet power in elliptical galaxies
08620751NORMAL GALAXIES: X-RAY POPULATIONS Andreas Zezas The evolution of merging galaxies: A Combined Chandra-Spitzer study
08620975NORMAL GALAXIES: X-RAY POPULATIONS Jonathan Grindlay Serving ChaMPlane Science, Data and Tools
08620983NORMAL GALAXIES: X-RAY POPULATIONS Arunav Kundu Probing the Effects of Globular Cluster Age on Low Mass X-ray Binary Formation
08700877ACTIVE GALAXIES AND QUASARS Nahum Arav Physical Conditions in the Best Observed Warm Absorbers
08800084CLUSTERS OF GALAXIES Amalia Hicks Solving the Cooling Flow Mystery: Understanding Variations in Star Formation Efficiency Using the Chandra Archive
08800412CLUSTERS OF GALAXIES Paul Nulsen Potential fluctuations and turbulence in relaxed clusters
08900504EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS Yangsen Yao X-raying the OVI absorbers
08900548EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS Paul Green AGN and Galaxies from the ChaMP
08910739GALACTIC DIFFUSE EMISSION AND SURVEYS Q. Daniel Wang X-raying the Hot Gaseous Corona around the Milky Way

Subject Category:STARS AND WD

Proposal Number: 08200320

Title: Tabulation of L-shell and M-shell lines in the LETGS spectra of Cool Stars

PI Name: Peter Beiersdorfer

We propose a systematic identification of the lines in the LETGS spectra of the coronae of cool stars, with particular focus on Procyon and $\alpha$ Cen. The coronae of cools stars have (1) an abundance of low charge state ions with the most complex spectra and in greatest need of accurate tabulation, and (2) are most relevant for understanding the EUV emission from the Sun. We are in a unique position to make the needed line identifications by utilizing our experience in laboratory measurements in this wavelength region. At present, more than half of all features in these spectra are unidentified. Establishing a line list specifically for cool stars will thus significantly enhance the utility of LETGS observations.


Subject Category: STARS AND WD

Proposal Number: 08200572

Title: Constraining Wind Porosity and Mass-Loss Rates with X-ray Line-Profile Modeling of OB Stars

PI Name:David Cohen

Quantitative fitting of X-ray line profiles of OB stars has proven to be a powerful tool in analyzing the kinematics and spatial distribution of hot plasma in the winds of these stars. The picture that has emerged is one that is consistent with the wind-shock paradigm, with the major caveat that the effective opacities of the winds of O supergiants are an order of magnitude lower than expected. However, not just lower mass-loss rates, but also wind structure - clumping and the associated porosity - may also play a role in reducing the effective wind opacity. In order to determine the relative contribution of wind clumping and mass-loss rate reductions, we will fit a newly developed model of x-ray line profiles from a porous wind to roughly a dozen grating spectra in the Chandra archive


Subject Category:STARS AND WD

Proposal Number: 08200696

Title: An Archive of Chandra Observations of Regions of Star Formation - A renewal of ANCHORS

PI Name:Scott Wolk

We have created a web based archive of Chandra observations of young clusters and other regions of star formation currently containing over 10,000 objects. For each object, X-ray photometric, temporal and spectroscopic analysis are performed, as is correlation with the 2MASS catalog. Here we propose for a continuation of support for this uniform source archive so that we may: (1) Continue to populate the archive with observations from 2006 and 2007 as well as continuing to measure optical photometry for clusters which are lacking. (2) Make our products available via the VO and use the VO to populate source specific derived data including masses and ages. (3) Make a plethora of incremental improvements to the first release. Our goal is to provide a community resource for analysis.


Subject Category: SN, SNR AND ISOLATED NS

Proposal Number:08500812

Title: Pulsar Wind Nebula Generation: A Spin-down Power Threshold?

PI Name: Eric Gotthelf

We propose to complete a Chandra X-ray spectroscopic survey of energetic rotation-powered pulsars down to a spin-down power limit of Edot > 2E36 erg/s. The current survey suggests that all pulsars with Edot > Edot_c ~ 4E36 erg/s are X-ray bright, manifest a distinct pulsar wind nebula (PWN), and are associated with a supernova event. Below Edot_c, the X-ray flux ratio F_PWN/F_PSR is found to decrease by an order-of-magnitude. Our goal is to test this empirical result by analyzing a complete and uniform sample of high Edot pulsars that become available in the Chandra archive this AO. Uncovering a spin-down power threshold will provide an important new constraint on pulsar emission models.


Subject Category:NORMAL GALAXIES: DIFFUSE EMISSION

Proposal Number:08610100

Title:Understanding the Origin of Diffuse X-ray Emission in the Halos and Disks of Disk Galaxies

PI Name:David Strickland

Theory predicts three mechanisms for generating hot gaseous halos around disk ga laxies, each of which have distinct implications in models of galaxy formation and evolution. Hot gas can be ejected from the disk because of (i) core-collapse SNe activity from massive star formation and (ii) SN 1a from long-lived lower mass stars, or (iii) low metallicity gas can fall in from the IGM. Do all of these mechanisms operate, and if so, when? I will characterize in detail the spatial distribution and spectral properties of the diffuse thermal X-ray emission in and around 51 roughly edge-on disk galaxies (Hubble types S0 and later) from the Chandra archive, and thus disentangle the contributions of star formation, SN 1a and accretion in generating X-ray emitting halos around disk galaxies.


Subject Category: NORMAL GALAXIES: DIFFUSE EMISSION

Proposal Number: 08610275

Title: Decomposing the X-ray Emission from the M31 Bulge

PI Name: Zhiyuan Li

About 40 Chandra ACIS observations have been carried out toward the central region of M31. We propose to use these observations to map out the entire M31 bulge and to characterize for the first time both its point-like and diffuse X-ray components. Specifically and step-by-step, we will 1) construct a source luminosity function down to 5x10^{34} ergs/s in the 0.5-8 keV band, 2) calibrate the collective X-ray emissivity of fainter, unresovled stellar populations, 3) characterize and model the diffuse hot gas, both spatially and spectrally. The results will represent a unique bulge-wide decomposition of the X-ray emission, which is badly needed for both understanding the high-energy processes in the M31 bulge and interpreting X-ray observations of other galactic bulges, including our own.


Subject Category:NORMAL GALAXIES: DIFFUSE EMISSION

Proposal Number: 08610295

Title: The relation between accretion rate and jet power in elliptical galaxies.

PI Name:Steven Allen

Our previous work has established a tight correlation between P_Bondi and P_jet for X-ray bright elliptical galaxies with active central radio sources and clear bubbles. These results imply an instantaneous efficiency of ~2 per cent for converting the energy associated with the rest mass of accreted matter into jet power. The question that we now seek to address - which is fundamental for cosmological studies - is: what is the time-averaged power and efficiency with which energy is fed back into the surrounding gas? To answer this, we propose joint Chandra X-ray observations of a complete X-ray flux, luminosity and distance-limited sample of elliptical galaxies, which will allow us to establish the duty-cycle and time-averaged efficiency of AGN heating.


Subject Category: NORMAL GALAXIES: X-RAY POPULATIONS

Proposal Number: 08620751

Title: The evolution of merging galaxies: A Combined Chandra-Spitzer study

PI Name: Andreas Zezas

We propose a Chandra-Spitzer multiwavelength study of interacting galaxies. Our main goals are to investigate the relation between the degree of interaction and: (a) galaxian X-ray emission, (b) Ultra-luminous X-ray sources (ULXs), and (c) the presence of AGNs. We propose to use data from the extensive Chandra archive, together with sensitive new infrared observations from an on-going Spitzer AO2 program. The Spitzer data will allow us to improve the characterization of the merger state, map and measure the star-formation activity and trace extended warm dust emission. Also using IR line diagnostics we will infer the presence of embedded AGNs independently from the X-ray data and thus establish AGN diagnostics involving both bands.


Subject Category:NORMAL GALAXIES: X-RAY POPULATIONS

Proposal Number: 08620975

Title: Serving ChaMPlane Science, Data and Tools

PI Name: Jonathan Grindlay

We propose to continue our ChaMPlane survey of low luminosity X-ray sources near the galactic plane (b<12deg). Analysis of spatial distributions (logN-logS), spectral classification of sources (quantile decomposition), and continued optical and IR identifications will be carried out, and new studies of source populations conducted. Final database creation and archiving and analysis of the large dataset will be completed. New tools for serving the data will be made available, and all X-ray data products made available through cycle 7. X-ray vs. optical databases, images and catalogs will be posted on line and published for widescale use by the community. Support from the archive program is required to complete this major effort.


Subject Category:NORMAL GALAXIES: X-RAY POPULATIONS

Proposal Number: 08620983

Title:Probing the Effects of Globular Cluster Age on Low Mass X-ray Binary Formation

PI Name:Arunav Kundu

We propose to study the LMXBs in archival Chandra data of 8 nearby elliptical galaxies in order to probe the effects of globular cluster (GC) age on the LMXB formation rate. Theoretical models suggest that GCs can only retain neutron stars if the progenitor is bound to a sufficiently massive intermediate mass binary companion that can damp the supernova kick velocity. Since the reservoir of intermediate mass stars is swiftly depleted a large population of X-ray binaries should be seen in younger GCs. Surprisingly, a published pilot study of a small sample of clusters shows no such age dependence. Optical and infrared data of ~800 GCs in our program galaxies with a large range of cluster ages will allow us to sensitively probe the effect of GC age on LMXB formation and test the models.


Subject Category:ACTIVE GALAXIES AND QUASARS

Proposal Number: 08700877

Title: Physical Conditions in the Best Observed Warm Absorbers

PI Name: Nahum Arav

We propose to analyze the three best Chandra warm-aborber data-sets totaling more than 2 Msec. The analysis of the NGC~3783 and NGC~5548 observations was done assuming the absorber fully covers the emission source. Our preliminary results show clear evidence for velocity dependent covering fraction in the 900 ks HETG observations of the warm absorber in NGC~3783. These findings can radically change the conclusions regarding the nature of the absorber. Previous analyses of these observations found two or three co-existing absorbing components with very different temperatures but similar pressure. This important finding must be reexamined in the light of our new findings. To date, no analysis results from the third data set, a 500 ks HETG observation of MCG-6-30-15, were published.


Subject Category:CLUSTERS OF GALAXIES

Proposal Number: 08800084

Title: Solving the Cooling Flow Mystery: Understanding Variations in Star Formation Efficiency Using the Chandra Archive

PI Name: Amalia Hicks

Even after recent studies the amount of cooling material per year is quite large in many cooling flow clusters, implying high star formation rates. In our pilot UV imaging study of 9 cooling flow clusters we detect, in some, a significant fraction of this implied star formation. Our data however show a wide variation in star formation efficiency, suggesting the existence of an additional parameter, the nature of which is widely debated and may involve cluster mergers, non-thermal plasma, or AGN heating, all of which are easily detected in Chandra images. With Chandra observations of 40 clusters and complimentary in-hand UV imaging data we will determine, via morphological measurements on arcsec scales, how these processes are related to extreme variations in UV emission and star formation.


Subject Category:CLUSTERS OF GALAXIES

Proposal Number: 08800412

Title:Potential fluctuations and turbulence in relaxed clusters

PI Name:Paul Nulsen

Substructure in clusters of galaxies, including the (sub)halos of individual galaxies, creates small but detectable density and temperature fluctuations in the intracluster medium (ICM). Turbulence at the levels predicted by simulations creates a similar level of disturbances, distinguished by a different relationship between the temperature and density fluctuations. We propose to examine the distribution of temperature and density fluctuations in the ICM for a sample of about ten nearby, relaxed clusters with deep observations in the Chandra archive. This will test models of large-scale structure formation and constrain the masses of galaxies within clusters.


Subject Category: EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 08900504

Title: X-raying the OVI absorbers

PI Name: Yangsen Yao

The observed z>0 OVI absorbers have been regarded as a significant reservoir of the ``missing baryons''. This interpretation is subject to the assumption of collisional ionization origin of these absorbers, which however, has not been verified yet. We propose to use the identified z>0 OVI systems as tracers to search for the corresponding OVII absorptions. With the proposed program, we could detect OVII with column density as low as log(N_OVII) ~14.5 at >3sigma significance. We intend to primarily investigate whether or not these OVI systems are collisionally ionized, and to constrain the baryon mass contained in the OVI absorbers.


Subject Category:EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 08900548

Title: AGN and Galaxies from the ChaMP

PI Name: Paul Green

The Chandra Multiwavelength Project (ChaMP), as the widest area sensitive (logfx > -15) X-ray survey to date, provides an invaluable probe of supermassive black hole accretion in 3 critical regimes; above z~3 to test the turnover of luminous quasars, below z~1 to track the population boom of lower luminosity AGN, and below z~0.3 to determine the fraction of galaxies hosting AGN. We request funding to leverage our investments both deep and wide. To go deep, we propose for i=23.5 NOAO Gemini-North multi-object spectroscopy in 4 key fields. To go wide, we have now analyzed 6 years of Chandra data, and will cross-correlate with the SDSS final data release across 399 fields to pave the L-z plane, measure the AGN fraction, and expand our large, uniform, multi-wavelength public database.


Subject Category:GALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 08910739

Title:X-raying the Hot Gaseous Corona around the Milky Way

PI Name: Q. Daniel Wang

Our Galaxy and its surrounding represent a unique laboratory in which we can conduct X-ray absorption line spectroscopy along multiple sight-lines to explore the global distribution as well as the thermal, chemical, and kinematic properties of diffuse hot gas. We propose an archival research to systematically analyze three AGN sight-lines (Mkn 421, 3C 273, and PKS 2125-304), best observed with the Chandra grating instruments with 2 Ms expsure. We will jointly fit zero-redshift O VII, O VIII, and Ne IX X-ray absorption lines with a spectral model that we have developed, which also allows for the inclusion of X-ray emission and far-UV absorption line data available along the same sight-lines. We will measure the hot gas properties, including the temperature distribution and scale length.


Smithsonian Institute Smithsonian Institute

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