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Spitzer, Very Large Telescope, and Very Large Array Observations of the Galactic Luminous Blue Variable Candidate HD 168625
Umana, G.; Hora, J. L.; Trigilio, C. +2 more
We present mid-IR and radio observations of the Galactic luminous blue variables (LBVs) candidate HD 168625 and its associated nebula. We obtained mid-IR spectroscopic observations using the Infrared Spectrograph on board the Spitzer Space Telescope, and performed mid-IR and radio imaging observations using VISIR on the Very Large Telescope and th…
Ancient Stars Beyond the Local Group: RR Lyrae Variables and Blue Horizontal Branch Stars in Sculptor Group Dwarf Galaxies
Rejkuba, M.; Da Costa, G. S.; Grebel, E. K. +1 more
We have used Hubble Space Telescope Advanced Camera for Surveys images to generate color-magnitude diagrams that reach below the magnitude of the horizontal branch in the Sculptor Group dwarf galaxies ESO294-010 and ESO410-005. In both diagrams, blue horizontal branch stars are unambiguously present, a signature of the existence of an ancient stel…
Dispelling Illusions of Reflection: A New Analysis of the 2007 May 19 Coronal "Wave" Event
Attrill, Gemma D. R.
A new analysis of the 2007 May 19 coronal wave-coronal mass ejection-dimmings event is offered employing base difference extreme-ultraviolet (EUV) images. Previous work analyzing the coronal wave associated with this event concluded strongly in favor of purely an MHD wave interpretation for the expanding bright front. This conclusion was based to …
An X-ray-selected Galaxy Cluster in the Lockman Hole at Redshift 1.753
Egami, Eiichi; Finoguenov, Alexis; Salvato, Mara +12 more
We have discovered an X-ray-selected galaxy cluster with a spectroscopic redshift of 1.753. The redshift is of the brightest cluster galaxy (BCG), which is coincident with the peak of the X-ray surface brightness. We also have concordant photometric redshifts for seven additional candidate cluster members. The X-ray luminosity of the cluster is (3…
Discovery of a Luminous Blue Variable with an Ejection Nebula Near the Quintuplet Cluster
Glass, I. S.; Morris, M. R.; Wang, Q. D. +5 more
We report on the discovery of a luminous blue variable (LBV) lying ≈7 pc in projection from the Quintuplet cluster. This source, which we call LBV G0.120 - 0.048, was selected for spectroscopy owing to its detection as a strong source of Paschen-α (Pα) excess in a recent narrowband imaging survey of the Galactic center region with the Hubble Space…
Quaoar: A Rock in the Kuiper Belt
Fraser, Wesley C.; Brown, Michael E.
Here we report Wide-Field Planetary Camera 2 observations of the Quaoar-Weywot Kuiper Belt binary. From these observations, we find that Weywot is on an elliptical orbit with an eccentricity of 0.14 ± 0.04, a period of 12.438 ± 0.005 days, and a semimajor axis of 1.45 ± 0.08 × 104 km. The orbit reveals a surprisingly high-Quaoar-Weywot …
Discovery of X-ray-emitting O-Ne-Mg-rich Ejecta in the Galactic Supernova Remnant Puppis A
Katsuda, Satoru; Petre, Robert; Hwang, Una +3 more
We report on the discovery of X-ray-emitting O-Ne-Mg-rich ejecta in the middle-aged Galactic O-rich supernova remnant Puppis A with Chandra and XMM-Newton. We use line ratios to identify a low-ionization filament running parallel to the northeastern edge of the remnant that requires super-solar abundances, particularly for O, Ne, and Mg, which we …
Direct Detection of an Ultraluminous Ultraviolet Source
Tao, Lian; Feng, Hua; Kaaret, Philip +1 more
We present Hubble Space Telescope observations in the far UV of the ultraluminous X-ray source in NGC 6946 associated with the optical nebula MF 16. Both a point-like source coincident with the X-ray source and the surrounding nebula are detected in the FUV. The point source has a flux of 5 × 10-16 erg s-1 cm-2 Å
A Precessing Jet in the CH Cyg Symbiotic System
Raymond, John C.; Karovska, Margarita; Carilli, Christopher L. +3 more
Jets have been detected in only a few symbiotic binaries to date, and CH Cyg is one of them. In 2001, a non-relativistic jet was detected in CH Cyg for the first time in X-rays. We carried out coordinated Chandra, Hubble Space Telescope (HST), and VLA observations in 2008 to study the propagation of this jet and its interaction with the circumbina…
Mode Identification of MHD Waves in an Active Region Observed with Hinode/EIS
Hara, H.; Kitagawa, N.; Yokoyama, T. +1 more
In order to better understand the possibility of coronal heating by MHD waves, we analyze Fe XII 195.12Å data observed with the EUV Imaging Spectrometer on board Hinode. We performed a Fourier analysis of EUV intensity and Doppler velocity time series data in the active region corona. Notable intensity and Doppler velocity oscillations were found …