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The Acoustic Showerglass. II. Imaging Active Region Subphotospheres

Braun, D. C.; Lindsey, Charles

Seismic diagnostics of the shallow subphotospheres of strong active regions are substantially impacted by large amplitude and phase perturbations introduced by overlying surface magnetic fields. These function as an ``acoustic showerglass'' that impairs the coherence of acoustic waves impinging onto the solar surface from below, degrading images o…

The X-Ray Properties of M101 ULX-1 = CXOKM101 J140332.74+542102

Mukai, K.; Kuntz, K. D.; Corbet, R. H. D. +2 more

We report our analysis of X-ray data on M101 ULX-1, concentrating on high-state Chandra and XMM-Newton observations. We find that the high state of M101 ULX-1 may have a preferred recurrence timescale. If so, the underlying clock may have periods around 160 or 190 days, or possibly around 45 days. Its short-term variations resemble those of X-ray …

Type 2 Counterparts of Narrow-Line Seyfert 1 Galaxies

Dewangan, G. C.; Griffiths, R. E.

Unified models based on viewing angle successfully explain the observed differences between type 1 and type 2 Seyfert galaxies. The existence of a range in accretion rates (m˙~0.001-1) relative to the Eddington rate (from broad-line Seyfert 1's to narrow-line Seyfert 1's, or NLS1's) and the unification of Seyfert galaxies imply that there must be …

Fluorescent Molecular Hydrogen Emission in IC 63: FUSE, Hopkins Ultraviolet Telescope, and Rocket Observations

France, K.; Feldman, P. D.; Andersson, B. -G. +1 more

We present far-ultraviolet observations of IC 63, an emission/reflection nebula illuminated by the B0.5 IV star γ Cas, located 1.3 pc from the nebula. Molecular hydrogen fluorescence was detected first in IC 63 by IUE and later at shorter wavelengths by ORFEUS. Here we present Far Ultraviolet Spectroscopic Explorer (FUSE) observations toward three…

The sub-Parker spiral structure of the heliospheric magnetic field

McComas, D. J.; Schwadron, N. A.

Recent studies have shown that the heliospheric magnetic field can be much more radial than the standard Parker spiral in the rarefactions of co-rotation interaction regions (CIRs). This effect can be explained by the motion of open magnetic field foot points at the Sun across the coronal hole boundary. Such motion causes magnetic field lines to b…

Cl 1205+44: A Fossil Group at z = 0.59

Romer, A. K.; Adami, C.; Durret, F. +6 more

This is a report of Chandra, XMM-Newton, Hubble Space Telescope, and Astrophysical Research Consortium telescope observations of an extended X-ray source at z=0.59. The apparent member galaxies range from spiral to elliptical, and are all relatively red (i^'-K_s about 3). We interpret this object to be a fossil group based on t…

High spatial resolution mid-infrared spectroscopy of NGC 5253: The stellar content of the embedded super-star cluster

Schaerer, D.; Sauvage, M.; Martín-Hernández, N. L.

We present the N-band (8-13 µm) spectrum of the hidden compact radio super-star cluster in NGC 5253, C2, obtained with TIMMI2 on the ESO 3.6 m telescope. The spectrum is characterised by a rising continuum due to warm dust, a silicate absorption and a strong [S IV] line at 10.5 µm. Weaker lines of [Ar II]I at 9.0 µm and [Ne II] a…

Observational evidence of the primary role played by photospheric motions in magnetic helicity transport before a filament eruption

Romano, P.; Contarino, L.; Zuccarello, F.

Many filament eruptions can be suitably described in the framework of the kink instability model, although it is not always easy to discriminate whether the helical flux rope writhes due to new emerging flux or to photospheric horizontal motions. In this paper we provide observational evidence of the important role which can be played by horizonta…

Cluster at the Magnetospheric Cusps

Escoubet, C. P.; Lavraud, B.; Owen, C. J. +9 more

Merging Galaxies in GOODS-S: First Extragalactic Results from Keck Laser Adaptive Optics

Koo, D. C.; Le Mignant, D.; Wright, S. A. +15 more

The Center for Adaptive Optics Treasury Survey aims to combine deep Hubble Space Telescope (HST) images in the optical with deep Keck adaptive optics (AO) data in the near-infrared (NIR) to study distant galaxies, active galactic nuclei, and supernovae. We recently achieved an important new milestone by securing the first Keck laser guide star AO …