Search Publications
Coronal Nonthermal Velocity Following Helicity Injection Before an X-Class Flare
Tsuneta, S.; Doschek, G. A.; Hara, H. +5 more
We explore the "pre-flare" behavior of the corona in a three-day period building up to an X-class flare on 2006 December 13 by analyzing EUV spectral profiles from the Hinode EUV Imaging Spectrometer (EIS) instrument. We found an increase in the coronal spectral line widths, beginning after the time of saturation of the injected helicity as measur…
HI in very metal-poor galaxies: the SBS 0335-052 system
Chengalur, Jayaram N.; Ekta, B.; Pustilnik, Simon A.
We present Giant Metrewave Radio Telescope, HI 21 cm observations of SBS 0335-052E and SBS 0335-052W, a close pair of dwarf galaxies, which are further unusual in being the most metal-poor star-forming galaxies known. We present images at several angular resolutions, ranging from ~40 to 4 arcsec. These images show that SBS 0335-052 is a strongly i…
Properties of the Diffuse X-ray Background toward MBM20 with Suzaku
Smith, R.; Gupta, A.; Lallement, R. +2 more
We used Suzaku observations of the molecular cloud MBM20 and a low neutral hydrogen column density region nearby to separate and characterize the foreground and background diffuse X-ray emission. A comparison with a previous observation of the same regions with XMM-Newton indicates a significant change in the foreground flux which is attributed to…
X-Ray Halo around the Spiral Galaxy NGC 4631 Observed with Suzaku
Sato, Kosuke; Ohashi, Takaya; Yamasaki, Noriko Y. +1 more
A Suzaku observation of the edge-on spiral galaxy NGC 4631 confirmed its X-ray halo extending out to about 10kpc from the galactic disk. The XIS spectra yielded the temperature and metal abundance for the disk and the halo regions. The observed abundance pattern for O, Ne, Mg, Si, and Fe is consistent with the metal yield from type II supernovae, …
One-hundred-km-scale basins on Enceladus: Evidence for an active ice shell
Schenk, Paul M.; McKinnon, William B.
Stereo-derived topographic mapping of ∼50% of Enceladus reveals at least 6 large-scale, ovoid depressions (basins) 90-175 km across and 800-to-1500 m deep and uncorrelated with geologic boundaries. In contrast, the south polar depression is larger and apparently shallower and correlates with active resurfacing. The shape and scale of the basins is…
Cometary masses derived from non-gravitational forces
Sosa, Andrea; Fernández, Julio A.
We compute masses and densities for 10 periodic comets with known sizes: 1P/Halley, 2P/Encke, 6P/d'Arrest, 9P/Tempel 1, 10P/Tempel 2, 19P/Borrelly, 22P/Kopff, 46P/Wirtanen, 67P/Churyumov-Gerasimenko and 81P/Wild 2. The method follows the one developed by Rickman and colleagues, which is based on the gas production curve and on the change in the or…
Delayed X-ray emission from fallback in compact-object mergers
Begelman, Mitchell C.; Rossi, Elena M.
When double neutron star or neutron star-black hole binaries merge, the final remnant may comprise a central solar-mass black hole surrounded by a ~0.01-0.1Msolar torus. The subsequent evolution of this disc may be responsible for short γ-ray bursts (SGRBs). A comparable amount of mass is ejected into eccentric orbits and will eventuall…
An atlas of predicted exotic gravitational lenses
Marshall, Phil; Orban de Xivry, Gilles
Wide-field optical imaging surveys will contain tens of thousands of new strong gravitational lenses. Some of these will have new and unusual image configurations, and so will enable new applications: for example, systems with high image multiplicity will allow more detailed study of galaxy and group mass distributions, while high magnification is…
Stellar Masses of Lyman Break Galaxies, Lyα Emitters, and Radio Galaxies in Overdense Regions at z = 4-6
White, Richard L.; Illingworth, Garth D.; Bouwens, Rychard J. +8 more
We present new information on galaxies in the vicinity of luminous radio galaxies (RGs) and quasars at zsime4, 5, and 6. These fields were previously found to contain overdensities of Lyman Break Galaxies (LBGs) or spectroscopic Lyα emitters, which were interpreted as evidence for clusters-in-formation ("protoclusters"). We use Hubble Space Telesc…
Integral field spectroscopy of ionized and molecular gas in cool cluster cores: evidence for cold feedback?
Swinbank, A. M.; Edge, A. C.; Wilman, R. J.
We present VLT-SINFONI K-band integral field spectroscopy of the central galaxies in the cool core clusters A1664, A2204 and PKS 0745-191, to probe the spatio-kinematic properties of the Paα and ro-vibrational H2 line emission.
In A1664, the two emission-line velocity systems seen in our previous Hα spectroscopy appear in both Paα …