Search Publications
Elemental Abundances in the Possible Type Ia Supernova Remnant G344.7-0.1
Yamaguchi, H.; Tanaka, M.; Maeda, K. +5 more
Recent studies on the Galactic supernova remnant (SNR) G344.7-0.1 have commonly claimed its origin to be a core-collapse supernova (SN) explosion, based on its highly asymmetric morphology and/or proximity to a star-forming region. In this paper, however, we present an X-ray spectroscopic study of this SNR using Suzaku, which is supportive of a Ty…
Deep Chandra Monitoring Observations of NGC 4649. II. Wide-field Hubble Space Telescope Imaging of the Globular Clusters
Brodie, Jean P.; Zezas, Andreas; Strader, Jay +7 more
We present g and z photometry and size estimates for globular clusters (GCs) in the massive Virgo elliptical NGC 4649 (M60) using a five-pointing Hubble Space Telescope/Advanced Camera for Surveys mosaic. The metal-poor GCs show a monotonic negative metallicity gradient of -0.43 ± 0.10 dex per dex in radius over the full radial range of the data, …
Deep Hubble Space Telescope Imaging in NGC 6397: Stellar Dynamics
Anderson, J.; Rich, R. M.; Dotter, A. +9 more
Multi-epoch observations with the Advanced Camera for Surveys on the Hubble Space Telescope provide a unique and comprehensive probe of stellar dynamics within NGC 6397. We are able to confront analytic models of the globular cluster with the observed stellar proper motions. The measured proper motions probe well along the main sequence from 0.8 t…
Hubble Space Telescope Narrowband Search for Extended Lyα Emission around Two z > 6 Quasars
Hennawi, Joseph F.; Strauss, Michael A.; Rix, Hans-Walter +8 more
We search for extended Lyα emission around two z > 6 quasars, SDSS J1030+0524 (z = 6.309) and SDSS J1148+5251 (z = 6.419) using Wide Field Camera 3 narrowband filters on board the Hubble Space Telescope. For each quasar, we collected two deep, narrowband images, one sampling the Lyα line+continuum at the quasar redshifts and one of the continuu…
Spatially Dependent Heating and Ionization in an ICME Observed by Both ACE and Ulysses
Laming, J. Martin; von Steiger, Rudolf; Rakowski, Cara E. +1 more
The 2005 January 21 interplanetary coronal mass ejection (ICME) observed by multiple spacecraft at L1 was also observed from January 21-February 4 at Ulysses (5.3 AU). Previous studies of this ICME have found evidence suggesting that the flanks of a magnetic cloud like structure associated with this ICME were observed at L1 while a more central cu…
On the Variations of Fundamental Constants and Active Galactic Nucleus Feedback in the Quasi-stellar Object Host Galaxy RXJ0911.4+0551 at z = 2.79
Menten, K. M.; Walter, F.; Henkel, C. +4 more
We report on sensitive observations of the CO(J = 7→6) and C I(3 P 2 → 3 P 1) transitions in the z = 2.79 QSO host galaxy RXJ0911.4+0551 using the IRAM Plateau de Bure interferometer. Our extremely high signal-to-noise spectra combined with the narrow CO line width of this source (FWHM = 120 km s-1<…
On the Relationship between the Coronal Magnetic Decay Index and Coronal Mass Ejection Speed
Xu, Yan; Liu, Chang; Jing, Ju +1 more
Numerical simulations suggest that kink and torus instabilities are two potential contributors to the initiation and prorogation of eruptive events. A magnetic parameter called the decay index (i.e., the coronal magnetic gradient of the overlying fields above the eruptive flux ropes) could play an important role in controlling the kinematics of er…
Interferometric CO(3-2) Observations toward the Central Region of NGC 1068
Matsushita, Satoki; Hwang, Chorng-Yuan; Espada, Daniel +2 more
We present CO(3-2) interferometric observations of the central region of the Seyfert 2 galaxy NGC 1068 using the Submillimeter Array, together with CO(1-0) data taken with the Owens Valley Radio Observatory Millimeter Array. Both the CO(3-2) and CO(1-0) emission lines are mainly distributed within ~5 arcsec of the nucleus and along the spiral arms…
NGC 5548: Lack of a Broad Fe Kα Line and Constraints on the Location of the Hard X-Ray Source
Liu, Y.; Elvis, M.; Krongold, Y. +2 more
We present an analysis of the co-added and individual 0.7-40 keV spectra from seven Suzaku observations of the Sy 1.5 galaxy NGC 5548 taken over a period of eight weeks. We conclude that the source has a moderately ionized, three-zone warm absorber, a power-law continuum, and exhibits contributions from cold, distant reflection. Relativistic refle…
Discovery of Variability of the Progenitor of SN 2011dh in M 51 Using the Large Binocular Telescope
Kochanek, C. S.; Stanek, K. Z.; Gerke, J. R. +1 more
We show that the candidate progenitor of the core-collapse SN 2011dh in M 51 (8 Mpc away) was fading by 0.039 ± 0.006 mag yr-1 during the 3 years prior to the supernova, and that this level of variability is moderately unusual for other similar stars in M 51. While there are uncertainties about whether the true progenitor was a blue com…