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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…
Multiwavelength Studies of Hercules X-1 during Short High and Anomalous Low States: On-again, Off-again
McCray, R.; O'Brien, K.; Boroson, B. +4 more
We present results from multiwavelength observations of the Hercules X-1 system during a short high state (SHS) and during an anomalous low state (ALS). The magnitude of deviation from spin-up appears to be positively correlated with duration of the ALS. Such a correlation is consistent with an interpretation of the ALS in terms of a change in mas…
Optical Identification of the X-Ray Burster in the Globular Cluster NGC 1851
Anderson, Scott F.; Margon, Bruce; Deutsch, Eric W. +2 more
We have obtained exposures of the field of X0512-401 in the globular cluster NGC 1851, in X-rays with the Chandra X-Ray Observatory, and in the far-UV with the Hubble Space Telescope. We derive an accurate new X-ray position (within ~1") for X0512-401, which enables us to confirm that the only plausible candidate for the optical/UV counterpart is …
Search for Evidence of Alpha-Particle Beams during a Solar Flare Observed by the Coronal Diagnostic Spectrometer aboard the Solar and Heliospheric Observatory
Brosius, Jeffrey W.
We observed NOAA Active Region 9090 (N13°, W39°) with the Coronal Diagnostic Spectrometer (CDS) and the Extreme-Ultraviolet Imaging Telescope (EIT) aboard the Solar and Heliospheric Observatory spacecraft between 18:17 and 21:09 UT on 2000 July 24 to search for evidence of alpha-particle beams during solar flares. Theoretically, an alpha-particle …
Discovery of Associated Absorption Lines in an X-Ray Warm Absorber:Hubble Space Telescope Faint Object Spectrograph Observations of MR 2251-178
Elvis, Martin; Mathur, Smita; Wilkes, Belinda +1 more
The presence of a ``warm absorber'' was first suggested to explain spectral variability in an X-ray spectrum of the radio-quiet quasi-stellar object (QSO) MR 2251-178. A unified picture, in which X-ray warm absorbers and ``intrinsic'' UV absorbers are the same, offers the opportunity to probe the nuclear environment of active galactic nuclei. To t…
Optical-Near-Infrared Color Gradients in Early-Type Galaxies at z<=1.0
Hinkley, Sasha; Im, Myungshin
Recent studies based on line indices of nearby early-type galaxies suggest that stars in the galaxies' inner part may be younger and more metal-rich than stars in the outer part. If confirmed, the finding has a profound implication for the formation and evolution of early-type galaxies, since such age gradients naturally arise if merging played an…