Search Publications
Far Infrared mapping of NGC 891
Tuffs, R. J.; Kylafis, N. D.; Madore, B. F. +1 more
We present deep maps of dust emission from the edge-on spiral galaxy NGC 891, obtained with the ISOPHOT instrument on board the Infrared Space Observatory in broad band filters with reference wavelengths centered on 170 and 200 µm. Using new processing methods to remove the effects of detector transients from the data, we detect cold dust at…
The Purple Haze of η Carinae: Binary-induced Variability?
Smith, Nathan; Gull, Theodore R.; Collins, Nicholas R. +1 more
Asymmetric variability in ultraviolet images of the Homunculus obtained with the Advanced Camera for Surveys/High Resolution Camera on the Hubble Space Telescope suggests that η Carinae is indeed a binary system. Images obtained before, during, and after the recent ``spectroscopic event'' in 2003.5 show alternating patterns of bright spots and sha…
Jet-Gas Interactions in Markarian 78. I. Morphology and Kinematics
Wilson, Andrew S.; Whittle, Mark
We present a detailed study of the Seyfert 2 galaxy Markarian 78, using continuum and emission-line images and multiaperture spectra from the Hubble Space Telescope (HST) and a deep 3.6 cm VLA image. Our overall aim is to study the interaction between the radio source and the emission-line gas, since ground-based data already indicate the presence…
Cassini Radio Science
French, R. G.; Flasar, F. M.; Asmar, S. W. +10 more
Cassini radio science investigations will be conducted both during the cruise (gravitational wave and conjunction experiments) and the Saturnian tour of the mission (atmospheric and ionospheric occultations, ring occultations, determinations of masses and gravity fields). New technologies in the construction of the instrument, which consists of a …
XMM-Newton Observations of the Galactic Supernova Remnant CTB 109 (G109.1-1.0)
Sasaki, Manami; Smith, Randall K.; Plucinsky, Paul P. +3 more
We present the analysis of the X-ray Multimirror Mission (XMM-Newton) European Photon Imaging Camera (EPIC) data of the Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0). CTB 109 is associated with the anomalous X-ray pulsar (AXP) 1E 2259+586 and has an unusual semicircular morphology in both the X-ray and the radio and an extended X-ray brigh…
Absolute Proper Motion of the Fornax Dwarf Spheroidal Galaxy from Photographic and Hubble Space Telescope WFPC2 Data
Majewski, Steven R.; Keeney, Brian A.; Girard, Terrence M. +1 more
We have measured the absolute proper motion of the Fornax dwarf spheroidal galaxy from a combination of photographic plate material and Hubble Space Telescope Wide Field Planetary Camera 2 data that provide a time baseline of up to 50 yr. The extragalactic reference frame consists of eight QSO images and 48 galaxies. The absolute proper motion is …
Observing Mkn 421 with XMM-Newton: The EPIC-PN point of view
Tagliaferri, G.; Ghisellini, G.; Tavecchio, F. +1 more
We present three observations (four exposures) of Mkn 421 performed by XMM-Newton in November and December 2002, concentrating on the EPIC-PN camera data. The X-ray spectra were soft and steepened toward high energies. The source was highly variable and the hardness ratio plots displayed a clear harder-when-stronger correlation. During two complet…
Rapid Penumbral Decay following Three X-Class Solar Flares
Liu, C.; Qiu, J.; Wang, H. +3 more
We show strong evidence that penumbral segments decayed rapidly and permanently right after three X-class solar flares. Two of the three events occurred very recently in NOAA Active Region 10486, an X17 flare on 2003 October 28 and an X10 flare on 2003 October 29. The third X2.3 flare was observed in solar active region NOAA AR 9026 on 2000 June 6…
Spacecraft and Ground Anomalies Related to the October-November 2003 Solar Activity
Webb, David; Allen, Joe
During two weeks in late October and early November 2003, a series of large solar events led to high levels of energetic particles in geospace and produced overlapping large geomagnetic storms on 28-30 October. These storms caused effects ranging from power grid failures to satellite shutdowns. A Japanese satellite was lost completely, the U. S. F…
RHESSI Observations of a Simple Large X-Ray Flare on 2003 November 3
Liu, Wei; Liu, Siming; Jiang, Yan Wei +1 more
We present data analysis and interpretation of a simple X-class flare observed with RHESSI on 2003 November 3. In contrast to other X-class flares observed previously, this flare shows a very simple morphology with well-defined looptop (LT) and footpoint (FP) sources. The almost monotonic upward motion of the LT source and increase in separation o…