Search Publications
Evolution of the Reverse Shock Emission from SNR 1987A
Pun, C. S. J.; Smith, Nathan; Garnavich, Peter +13 more
We present new (2004 July) G750L and G140L Space Telescope Imaging Spectrograph (STIS) data of the Hα and Lyα emission from supernova remnant (SNR) 1987A. With the aid of earlier data, from 1997 October to 2002 October, we track the local evolution of Lyα emission and both the local and global evolution of Hα emission. The most recent observations…
Observation of Small-Scale Structure Using Sextupole Lensing
Irwin, John; Shmakova, Marina
Gravitational lensing by foreground halos with masses as small as 1010 Msolar can induce observable second-order shape distortions in background galaxy images in addition to the well-known elliptical shape distortion produced by first-order shear. Furthermore, the orientation of the second-order distortions is correlated with…
Variability Study of Seyfert 2 Galaxies with XMM-Newton
Awaki, Hisamitsu; Leighly, Karen M.; Murakami, Hirokatsu +1 more
We present the results of timing analysis of XMM-Newton observations of Seyfert 2 galaxies in order to search for differences in the mean properties of Seyfert 1 galaxies and Seyfert 2 galaxies. We selected 13 Seyfert 2 galaxies from the XMM-Newton archive that have hard X-ray components in their spectra and calculated the excess variance (σ2…
The 2003 October-November Fast Halo Coronal Mass Ejections and the Large-Scale Magnetic Field Structures
Liu, Y.; Hayashi, K.
The coronal magnetic field, computed from synoptic maps of the magnetic field and a potential field source surface (PFSS) model, reveals special configurations related to the active regions that were associated with most, if not all, fast halo coronal mass ejections (CMEs) in 2003 October-November. It was shown that these active regions emerged in…
A Light Echo from Type Ia SN 1995E?
Quinn, Jason L.; Garnavich, Peter M.; Li, Weidong +4 more
We identify a light echo candidate from Hubble Space Telescope (HST) imaging of NGC 2441, the host galaxy of the Type Ia supernova 1995E. From the echo's angular size and the estimated distance to the host galaxy, we find a distance of 207+/-35 pc between the dust and the site of the supernova. If confirmed, this echo brings the total number of ob…
The Nature of Blue Early-Type Galaxies in the GOODS Fields
Lee, Myung Gyoon; Hwang, Ho Seong; Lee, Joon Hyeop
We present a study of the nature of the blue early-type galaxies (BEGs) in the GOODS North and South fields using the GOODS archival HST ACS data. Using visual inspection, we have selected 58 BEGs and 113 normal red early-type galaxies (REGs) in the sample of 1949 galaxies with spectroscopic redshifts. We find that the BEGs are generally bluer, fa…
Chandra Observations of the Transient 7 s X-ray Pulsar AX J1845.0-0258
Gotthelf, E. V.; Gaensler, B. M.; Kaspi, V. M. +1 more
We present the results of Chandra X-Ray Observatory observations of the transient anomalous X-ray pulsar candidate AX J1845.0-0258 in apparent quiescence. Within the source's error circle, we find a point source and possible counterpart, which we designate CXOU J184454.6-025653. No coherent pulsations are detected, and no extended emission is seen…
High-Resolution Absorption Spectroscopy of Multiphase, High-Metallicity Gas Associated with the Luminous Quasar HE 0226-4110
Tripp, Todd M.; Sembach, Kenneth R.; Savage, Blair D. +2 more
We present FUSE and HST STIS observations of the absorption-line system near the emission redshift of the radio-quiet, X-ray-bright quasar HE 0226-4110 (z=0.495, V=15.2). The spectra cover the rest-frame wavelength range 610-1150 Å, and we detect a wide range of ionization species, including four adjacent stages of oxygen: O III-VI, which reveal a…
Confronting X-Ray Emission Models with the Highest Redshift Kiloparsec-Scale Jets: The z=3.89 Jet in Quasar 1745+624
Cheung, C. C.; Stawarz, Ł.; Siemiginowska, A.
A newly identified kiloparsec-scale X-ray jet in the high-redshift z=3.89 quasar 1745+624 is studied with multifrequency radio, HST, and Chandra X-ray imaging data. This is only the third large-scale X-ray jet beyond z>3 known and is further distinguished as being the most luminous relativistic jet observed at any redshift, exceeding 1045<…
Helioseismically Determined Near-Surface Flows Underlying a Quiescent Filament
Toomre, Juri; Hindman, Bradley W.; Haber, Deborah A.
The extended filaments seen in Hα images of the solar disk, and the corresponding prominences when viewed at the solar limb, are one of the great hallmarks of solar magnetism. Such arches of magnetic field and the coronal plasma structures they support are both beautiful and enigmatic. Many models of filament formation and maintenance invoke the e…