Search Publications
Ionizing Photons and Extreme-Ultraviolet Excesses in Clusters of Galaxies
Bland-Hawthorn, J.; Maloney, Philip R.
Observations with the Extreme Ultraviolet Explorer satellite are purported to show extreme-ultraviolet (EUV) and soft X-ray excesses in several clusters of galaxies. If interpreted as thermal emission, this would imply the presence of warm (T~106 K) gas in these clusters with a mass comparable to that of gas at coronal temperatures. If …
Far Ultraviolet Spectroscopic Explorer Observations of a Supernova Remnant in the Line of Sight to HD 5980 in the Small Magellanic Cloud
Blair, William P.; Hoopes, Charles G.; Sembach, Kenneth R. +1 more
We report a detection of far-ultraviolet absorption from the supernova remnant SNR 0057-7226 in the Small Magellanic Cloud (SMC). The absorption is seen in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of the luminous blue variable/Wolf-Rayet star HD 5980. Absorption from O VI λ1032 and C III λ977 is seen at a velocity of 300 km s
Stellar Encounters with the β Pictoris Planetesimal System
Kalas, Paul; Deltorn, Jean-Marc; Larwood, John
We use data from the Hipparcos catalog and the Barbier-Brossat & Figon catalog of stellar radial velocities to test the hypothesis that the β Pic planetesimal disk was disrupted by a close stellar encounter. We trace the space motions of 21,497 stars and discover 18 that have passed within 5 pc of β Pic in the past 1 Myr. β Pic's closest encou…
Detection of a Corrugated Velocity Pattern in the Spiral Galaxy NGC 5427
Pérez, Enrique; Alfaro, Emilio J.; González Delgado, Rosa M. +2 more
Here we report the detection, in Hα emission, of a radial corrugation in the velocity field of the spiral galaxy NGC 5427. The central velocity of the Hα line displays coherent, wavy-like variations in the vicinity of the spiral arms. The spectra along three different arm segments show that the maximum amplitude of the sinusoidal line variations a…
The Super-Star Cluster NGC 1569-A Resolved on Subparsec Scales with Hubble Space Telescope Spectroscopy
Ho, Luis C.; Maoz, Dan; Sternberg, Amiel
We present 3000-10000 Å Hubble Space Telescope (HST)/Space Telescope Imaging Spectrograph long-slit spectroscopy of the bright super-star cluster A (SSC-A) in the dwarf starburst galaxy NGC 1569. The 0.05" HST angular resolution allows us, for the first time, to probe for spatial variations in the stellar population of an ~106 Msol…
Mid-Infrared Observations of the Mira Circumstellar Environment
Fazio, Giovanni G.; Marengo, Massimo; Karovska, Margarita +4 more
This Letter presents results from high angular resolution mid-IR imaging of the Mira AB circumbinary environment using the Mid-InfraRed Array Camera MIRAC3 at the NASA Infrared Telescope Facility. We resolved the dusty circumstellar envelope at 9.8, 11.7, and 18 µm around Mira A (ο Ceti) and measured the size of the extended emission. Strong…
Modeling the Interstellar Medium-Stellar Wind Interactions of λ Andromedae and ɛ Indi
Zank, Gary P.; Wood, Brian E.; Müller, Hans-Reinhard
A numerical study is presented of the interaction between the partially ionized interstellar medium (ISM) and the stellar wind of the very active RS CVn-type binary star λ And (G8 IV-III+?). Similar to results found for the heliosphere-ISM interaction, a termination shock, a tangential discontinuity (the ``astropause''), and a bow shock are found …
Chandra Detection of the Radio and Optical Double Hot Spot of 3C 351
Bondi, M.; Brunetti, G.; Comastri, A. +4 more
In this Letter, we report a Chandra X-ray detection of the double northern hot spot of the radio quasar 3C 351. The hot spot has also been observed in the optical with the Hubble Space Telescope (R band) and with the 3.5 m Telescopio Nazionale Galileo (B band). The radio-to-optical and X-ray spectra are interpreted as the results of the synchrotro…
On the Evolution of the Solar Photospheric and Coronal Magnetic Field
Schrijver, Carolus J.; Handy, Brian N.
The Extreme Ultraviolet Imaging Telescope (EIT) and the Michelsen Doppler Imager (MDI) instruments on the Solar and Heliospheric Observatory (SOHO) ran a coordinated observing campaign over the dates 1997 August 10-14. MDI generated 1.2" resolution magnetograms (0.6" pixels) of the solar photosphere at a nominal cadence of one minute while EIT obs…
Hubble Space Telescope Imagery and Canada-France-Hawaii Telescope Fabry-Perot Two-dimensional Spectroscopy in Hα of the Ejected Nebula M1-67: Turbulent Status
Moffat, Anthony F. J.; Joncas, Gilles; Grosdidier, Yves +2 more
Bright circumstellar nebulae around massive stars are potentially useful to derive time-dependent mass-loss rates and hence constrain the evolution of the central stars. A key case in this context is the relatively young ejection-type nebula M1-67 around the runaway Population I Wolf-Rayet star WR 124 (=209 BAC), which exhibits a WN 8 spectrum. Wi…