Spatially Resolved Chandra HETG Spectroscopy of the NLR Ionization Cone in NGC 1068 (2009)
Evans, Daniel A., Ogle, Patrick M., Marshall, Herman L., Nowak, Mike A., Bianchi, Stefano, Guainazzi, Matteo, ...
We present initial results from a new 440-ks Chandra HETG GTO observation of the canonical Seyfert 2 galaxy NGC 1068. The proximity of NGC 1068, together with Chandra's superb spatial and spectral...
X-ray Emission and Corona of the Young Intermediate Mass Binary $\theta^1$ Ori E (2009)
Huenemoerder, David P., Schulz, Norbert S., Testa, Paola, Kesich, Anthony, Canizares, Claude R.
Theta 1 Ori E is a young, moderate mass binary system, a rarely observed case of spectral-type G-giants of about 3 Solar masses, which are still collapsing towards the main sequence. We have obtained...
Evans, Daniel A., Ogle, Patrick M., Marshall, Herman L., Nowak, Mike A., Bianchi, Stefano, Guainazzi, Matteo, ...
We present initial results from a new 440-ks Chandra HETG GTO observation of the canonical Seyfert 2 galaxy NGC 1068. The proximity of NGC 1068, together with Chandra's superb spatial and spectral...
High resolution X-ray spectroscopy of the multiphase interstellar medium toward Cyg X-2 (2009)
Yao, Yangsen, Schulz, Norbert S., Gu, Ming F., Nowak, Michael A., Canizares, Claude R.
High resolution X-ray absorption spectroscopy is a powerful diagnostic tool for probing chemical and physical properties of the interstellar medium (ISM) at various phases. We present detections of K...
High-Resolution X-ray Spectroscopy of SNR 1987A: Chandra LETG and HETG Observations in 2007 (2008)
Zhekov, Svetozar A., McCray, Richard, Dewey, Daniel, Canizares, Claude R., Borkowski, Kazimierz J., Burrows, David N., ...
We present an extended analysis of the deep Chandra LETG and HETG observations of the supernova remnant 1987A (SNR 1987A) carried out in 2007. The global fits to the grating spectra show that the...
Nowak, Michael A., Juett, Adrienne, Homan, Jeroen, Yao, Yangsen, Wilms, Joern, Schulz, Norbert S., ...
We present simultaneous Chandra-HETG and RXTE observations of a moderate flux `soft state' of the black hole candidate 4U1957+11. These spectra, having a minimally discernible hard X-ray excess, are...
Modeling the SS 433 Jet Bends (2008)
Marshall, Herman L., Canizares, Claude R., Schulz, Norbert S., Heinz, Sebastian, Hillwig, Todd C., Mioduszewski, Amy J.
We fit Chandra HETGS data obtained for the unusual X-ray binary SS 433. While line strengths and continuum levels hardly change, the jet Doppler shifts show aperiodic variations that probably result...
Limits on Hot Galactic Halo Gas from X-ray Absorption Lines (2007)
Yao, Yangsen, Nowak, Michael A., Wang, Q. Daniel, Schulz, Norbert S., Canizares, Claude R.
Although the existence of large-scale hot gaseous halos around massive disk galaxies have been theorized for a long time, there is yet very little observational evidence. We report the Chandra and...
Confirming the Detection of an Intergalactic X-ray Absorber Toward PKS 2155-304 (2007)
Fang, Taotao, Canizares, Claude R., Yao, Yangsen
We present new observations on PKS 2155-304 with the Chandra Low Energy Transmission Grating Spectrometer (LETG), using the Advanced CCD Imaging Spectrometer (ACIS). We confirm the detection of an...
X-ray Variability in the Young Massive Triple theta2 Ori A (2006)
Schulz, Norbert S., Testa, Paola, Huenemoerder, David P., Ishibashi, Kazunori, Canizares, Claude R.
Massive stars rarely show intrinsic X-ray variability. The only O-stars credited to be intrinsically variable are theta1 Ori C due to effects from magnetic confinement of its wind, and theta2 Ori A...
Determining the Nature of the SS 433 Binary Using an X-ray Spectrum During Eclipse (2006)
Lopez, Laura A., Marshall, Herman L., Canizares, Claude R., Schulz, Norbert S., Kane, Julie F.
We test the physical model of the relativistic jets in the galactic X-ray binary SS 433 proposed in our previous paper using additional observations from the Chandra High Energy Transmission Grating...
Scott, Jennifer E., Kriss, Gerard A., Lee, Julia C., Quijano, Jessica Kim, Brotherton, Michael, Canizares, Claude R., ...
We present simultaneous X-ray, far-ultraviolet, and near-ultraviolet spectra of the Seyfert 1 galaxy NGC 7469 obtained with the Chandra X-Ray Observatory, the Far Ultraviolet Spectroscopic Explorer,...
Canizares, Claude R., Davis, John E., Dewey, Daniel, Flanagan, Kathryn A., Galton, Eugene B., Huenemoerder, David P., ...
Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of flight experience....
Fang, Taotao, Canizares, Claude R., Marshall, Herman L.
We present a survey of six low to moderate redshift quasars with Chandra and XMM-Newton. The primary goal is to search for the narrow X-ray absorption lines produced by highly ionized metals in the...
The Evolution of Structure in X-ray Clusters of Galaxies (2005)
Jeltema, Tesla E., Canizares, Claude R., Bautz, Mark W., Buote, David A.
Using Chandra archival data, we quantify the evolution of cluster morphology with redshift. Clusters form and grow through mergers with other clusters and groups, and the amount of substructure in...
Humphrey, Philip J., Buote, David A., Canizares, Claude R.
We present spectral analysis of the diffuse emission in the normal, isolated, moderate-Lx S0 NGC 1332, constraining both the temperature profile and the metal abundances in the ISM. The...
The Coronal X-ray Spectrum of the Multiple Weak-Lined T Tauri Star System HD 98800 (2004)
Kastner, Joel H., Huenemoerder, David P., Schulz, Norbert S., Canizares, Claude R., Li, Jingqiang, Weintraub, David A.
We present high-resolution X-ray spectra of the multiple (hierarchical quadruple) weak-lined T Tauri star system HD 98800, obtained with the High Energy Transmission Gratings Spectrograph (HETGS)...
Stellar Coronal Spectroscopy with the Chandra HETGS (2003)
Huenemoerder, David P., Boroson, Bram, Schulz, Norbert S., Canizares, Claude R., Buzasi, Derek L., Preston, Heather L., ...
Spectroscopy with the Chandra High Energy Transmission Grating Spectrometer provides details on X-ray emission and activity from young and cool stars through resolution of emission lines from a...
The Evolution of Cluster Substructure with Redshift (2003)
Jeltema, Tesla E., Canizares, Claude R., Bautz, Mark W., Buote, David A.
Using Chandra archival data, we quantify the evolution of cluster morphology with redshift. To quantify cluster morphology, we use the power ratio method developed by Buote and Tsai (1995). Power...
Huenemoerder, David P., Canizares, Claude R., Drake, Jeremy J., Sanz-Forcada, Jorge
We observed the coronally active eclipsing binary, AR Lac, with the High Energy Transmission Grating on Chandra for a total of 97 ks, spaced over five orbits, at quadratures and conjunctions....
Schulz, Norbert S., Canizares, Claude R., Huenemoerder, Dave P., Tibbetts, Kevin J.
We analyzed high resolution X-ray spectra in the wavelength range of 1.5 -- 25 A of three of its X-ray brightest members obtained with the High Energy Transmission Grating Spectrometer (HETGS)...
The Evolution of Cluster Substructure (2003)
Jeltema, Tesla E., Canizares, Claude R., Bautz, Mark W., Buote, David A.
Using Chandra archival data, we have begun a study to quantify the evolution of cluster morphology with redshift. To quantify cluster morphology, we use the power ratio method developed by Buote and...
X-ray Source Population in the Elliptical Galaxy NGC 720 with Chandra (2002)
Jeltema, Tesla E., Canizares, Claude R., Buote, David A., Garmire, Gordon P.
With a Chandra ACIS-S3 observation, we detect 42 X-ray point sources in the elliptical galaxy NGC 720, including a possible central source. Most of these sources will be low-mass X-ray binaries...
Chandra X-Ray Spectroscopy and Imaging of the Galaxy Cluster PKS 0745-191 (2002)
Hicks, Amalia K., Wise, Michael W., Houck, John C., Canizares, Claude R.
We present a detailed spectral and spatial analysis of the galaxy cluster PKS 0745-191, using recent observations from the Chandra X-ray Observatory. The data provide information on the temperature...
Chandra Evidence for a Flattened, Triaxial Dark Matter Halo in the Elliptical Galaxy NGC 720 (2002)
Buote, David A., Jeltema, Tesla E., Canizares, Claude R., Garmire, Gordon P.
(Abridged) We present an analysis of a Chandra ACIS-S observation of the elliptical galaxy NGC 720 to verify the existence of a dark matter (DM) halo and to measure its ellipticity. The ACIS-S3 image...
Chandra/HETGS Spectroscopy of the Anomalous X-ray Pulsar 4U 0142+61 (2001)
Juett, Adrienne M., Marshall, Herman L., Chakrabarty, Deepto, Canizares, Claude R., Schulz, Norbert S.
We report on a 25 ks observation of the anomalous X-ray pulsar 4U 0142+61 with the High Energy Transmission Grating Spectrometer (HETGS) on the Chandra X-ray Observatory. The continuum spectrum is...
The Ionized Stellar Wind in Vela X-1 During Eclipse (2001)
Schulz, Norbert S., Canizares, Claude R., Lee, Julia C., Sako, Masao
We present a first analysis of a high resolution X-ray spectrum of the ionized stellar wind of Vela X-1 during eclipse. The data were obtained with the High Energy Transmission Grating Spectrometer...
Kastner, Joel H., Huenemoerder, David P., Schulz, Norbert S., Canizares, Claude R., Weintraub, David A.
We present high resolution X-ray spectra of the X-ray bright classical T Tauri star, TW Hydrae, covering the wavelength range of 1.5-25 AA. The differential emission measure derived from fluxes of...
Simulating the X-ray Forest in a Lambda CDM Universe (2001)
Fang, T., Bryan, G. L., Canizares, Claude R.
Numerical simulations predict that a large number of baryons reside in intergalactic space at temperatures between 10^5-10^7 K. Highly-ionized metals, such as O VII and O VIII, are good tracers of...
The High Resolution X-ray Spectrum of SS 433 using the Chandra HETGS (2001)
Marshall, Herman L., Canizares, Claude R., Schulz, Norbert S.
We present observations of SS 433 using the Chandra High Energy Transmission Grating Spectrometer. Many emission lines of highly ionized elements are detected with the relativistic blue and red...
Double-Peaked X-Ray Lines from the Oxygen/Neon-Rich Accretion Disk in 4U1626-67 (2001)
Schulz, Norbert S., Chakrabarty, Deepto, Marshall, Herman L., Canizares, Claude R., Lee, Julia C., Houck, John
We report on a 39 ks observation of the 7.7-s low-mass X-ray binary pulsar 4U1626-67 with the High Energy Transmission Grating Spectrometer (HETGS) on the Chandra X-Ray Observatory. This ultracompact...
Chandra X-Ray Observatory Observation of the High-Redshift Cluster MS 1054-0321 (2001)
Jeltema, Tesla E., Canizares, Claude R., Bautz, Mark W., Malm, Michael R., Donahue, Megan, Garmire, Gordon P.
We observed MS 1054-0321, the highest redshift cluster of galaxies in the Einstein Medium Sensitivity Survey (EMSS), with the Chandra ACIS-S detector. We find the X-ray temperature of the cluster to...
X-Ray Spectroscopy of II Pegasi: Coronal Temperature Structure, Abundances, and Variability (2001)
Huenemoerder, David P., Canizares, Claude R., Schulz, Norbert S.
We have obtained high resolution X-ray spectra of the coronally active binary, II Pegasi (HD 224085), covering the wavelength range of 1.5-25 Angstroms. For the first half of our 44 ksec observation,...
HST-FOS Observations of M87: Ly-a Emission from the Active Galactic Nucleus (1999)
Sankrit, Ravi, Sembach, Kenneth R., Canizares, Claude R.
The Faint Object Spectrograph on the Hubble Space Telescope was used to obtain spectra of the central region of M87. These spectra cover the wavelength range 1140 - 1606 Angstrom and have a...
Exploring the Damped Lyman-alpha Clouds with AXAF (1998)
Fang, Taotao, Canizares, Claude R.
The High Energy Transmission Grating (HETG) Spectrometer on the Advanced X-ray Astrophysics Facility (AXAF) (scheduled for launch in August, 1998) will provide a new tool for the study of absorption...
Probing the hot IGM with AXAF (1998)
Canizares, Claude R., Fang, Taotao
The transmission grating spectrometers on AXAF have sufficient sensitivity and energy resolution to detect resonance X-ray absorption lines in the spectra of distant quasars. Such lines would be...
X-Ray Emission Line Ratios and Multiphase Gas in Elliptical Galaxies and Galaxy Clusters (1998)
Buote, David A., Canizares, Claude R., Fabian, A. C.
We examine the K shell emission lines produced by isothermal and simple multiphase models of the hot gas in elliptical galaxies and galaxy clusters to determine the most effective means for...
X-ray Isophote Shapes and the Mass of NGC 3923 (1998)
Buote, David A., Canizares, Claude R.
We present analysis of the shape and radial mass distribution of the E4 galaxy NGC 3923 using archival X-ray data from the ROSAT PSPC and HRI. The X-ray isophotes are significantly elongated with...
X-ray Measurements of the Shapes of Clusters and Galaxies (1996)
Canizares, Claude R., Buote, David A.
We summarize a series of papers reporting studies of the ellipticities of X-ray images of five Abell clusters and two early type galaxies to learn about the shape of the gravitational potential and...
The Nature of the X-Ray Emission and the Mass Distributions in Two Early-Type Galaxies (1996)
Buote, David A., Canizares, Claude R.
We present spectral analysis of $ASCA$ observations of the early-type galaxies NGC 720 (E4) and NGC 1332 (E7/S0) with emphasis on constraining the relative contribution to the X-ray emission from hot...
The Twisting X-ray Isophotes of the Elliptical Galaxy NGC 720 (1996)
Buote, David A., Canizares, Claude R.
We present spatial analysis of the deep (57ks) ROSAT HRI X-ray image of the E4 galaxy NGC 720. The orientation of the HRI surface brightness is consistent with the optical position angle $(PA)$...
X-ray Constraints on the Intrinsic Shape of the Lenticular Galaxy NGC 1332 (1995)
Buote, David A., Canizares, Claude R.
We have analyzed ROSAT PSPC X-ray data of the optically elongated S0 galaxy NGC 1332 with the purposes of constraining the intrinsic shape of its underlying mass and presenting a detailed...
X-ray Constraints on the Intrinsic Shapes and Baryon Fractions of Five Abell Clusters (1995)
Buote, David A., Canizares, Claude R.
We analyzed ROSAT PSPC images of the bright, nearby $(z