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Observed and Predicted Ratios of the Horizontal and Vertical Components of the Solar p-Mode Velocity Eigenfunctions
Kosovichev, Alexander G.; Schou, Jesper; Rhodes, Edward J., Jr. +2 more
We present evidence that the observed ratios of the horizontal and vertical components of the solar intermediate-degree p-mode velocity eigenfunctions closely match theoretical predictions of these ratios. This evidence comes from estimates of the observed eigenfunction component ratios that were obtained from the fitting of the p-mode oscillation…
The Location of the Nucleus and the Morphology of Emission-Line Regions in NGC 1068
Chary, Ranga-Ram; Thompson, Rodger I.; Corbin, Michael R. +1 more
This Letter presents new Near-Infrared Camera and Multi-Object Spectrometer data on the location of the nucleus and the morphology of hydrogen and [Si VI] emission in NGC 1068. The peak of the emission at 2.2 µm is a strong point source that marks the location of the nucleus. The [Si VI] line emission region consists of two main components, …
Variable Ultraviolet Absorption in the Spectrum of MR 2251-178
Charlton, Jane C.; Eracleous, Michael; Ganguly, Rajib
We present an ultraviolet spectrum of MR 2251-178 taken with Hubble Space Telescope (HST)/Space Telescope Imaging Spectrograph (STIS) with the G230L grating. The observation is part of a snapshot program of quasars (QSOs) that systematically searches for intrinsic absorption lines through variability. The sample consists of all QSOs observed with …
Arp 220: A Circumnuclear Polar Ring as an Alternative to a Double Nucleus?
Eckart, A.; Downes, D.
Recent millimeter interferometer observations of Arp 220 have yielded ~0.5" resolution images showing two strong concentrations of millimeter radio continuum and CO line emission embedded in a larger molecular gas disk (r~1 kpc). The interferometer observations also revealed a complex velocity field with steep velocity gradients across each of the…
The Nuclear Stellar Cluster in the Seyfert 1 Galaxy NGC 3227: High Angular Resolution Near-Infrared Imaging and Spectroscopy
Tacconi, L. J.; Schinnerer, E.; Eckart, A.
Near-infrared (NIR) high angular resolution speckle imaging and imaging spectroscopy of the nuclear region (~10''~840 pc) of the Seyfert 1 galaxy NGC 3227 are presented. The images reveal an unresolved nuclear source in the K band in addition to a nuclear stellar cluster that is slightly resolved in the J and H bands. The contribution o…
A Shock-induced Photodissociation Region in the HH 80/81 Flow: Far-Infrared Spectroscopy
Molinari, Sergio; Noriega-Crespo, Alberto; Spinoglio, Luigi
The two spectrometers on board the Infrared Space Observatory were used to observe the Herbig-Haro objects HH 80, 81, and 80N, as well as their candidate exciting source IRAS 18162-2048. The fine structure lines of [O I] 63 µm, [O I] 145 µm, and [C II] 158 µm are detected everywhere, while [N II] 122 µm and [O III] 88.3 &mi…
Eruption of a Flux Rope on the Disk of the Sun: Evidence for the Coronal Mass Ejection Trigger?
Harra, Louise K.; Mason, Keith O.; Culhane, J. Leonard +1 more
The first evidence of acceleration of a flux rope from the disk of the Sun using the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) is presented. A distinct blueshifted emission component (-480 km s-1) was observed by the EUV spectrometer on SOHO at the start of the impulsive phase of an X2.3 flar…
The Anomalous Infrared Emission of Abell 58
Kimeswenger, Stefan; Koller, Josef
We present a new model to explain the excess in mid- and near-infrared emission of the central, hydrogen-poor dust knot in the planetary nebula (PN) Abell 58. Current models disagree with ISO measurements because they apply an average grain size and equilibrium conditions only. We investigate grain size distributions and temperature fluctuations a…
Evidence for an Accelerating Wind as the Broad-Line Region in NGC 3516
Zheng, W.; Kriss, G. A.; Koratkar, A. P. +4 more
Spectroscopic data in wavelengths 900-3000 Å have been obtained in a low flux state of the nucleus of the Seyfert 1 galaxy NGC 3516. The line profiles show P Cygni characteristics, particularly in O VI λ1032, and are compared with data from an earlier and higher state. The profiles are suggestive of and consistent with an accelerating wind driven …
STIS and GHRS Observations of Warm and Hot Gas Overlying the Scutum Supershell (GS 018-04+44)
Sembach, Kenneth R.; Savage, Blair D.; Howk, J. Christopher
We present Space Telescope Imaging Spectrograph (STIS) and Goddard High Resolution Spectrograph (GHRS) observations of interstellar UV absorption toward HD 177989, a B0 III star at 4.9 kpc in the direction l=17.8d, b=-11.9d. The line of sight passes through the high-latitude ejecta of the Scutum supershell (GS 018-06+44), which is ~5° in diameter …