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Speckle Observations of Binary Stars with the WIYN Telescope. IV. Differential Photometry
Horch, Elliott P.; van Altena, William F.; Meyer, Reed D.
Five hundred seventy-six magnitude difference measures are presented for 260 binary stars. These measures are derived from CCD-based speckle observations taken at the WIYN 3.5 m telescope at Kitt Peak National Observatory during the period 1997-2000. Separations of the systems range from over 1" down to near the diffraction limit of the telescope.…
XMM-Newton observations of polars in low accretion states
Cropper, Mark; Wu, Kinwah; Ramsay, Gavin +3 more
<heading id="h0" level="1">ABSTARCT</heading> We have made a series of snap-shot observations of 37 polars using XMM-Newton. We found that 16 of these systems were in a low, or much reduced, accretion state. Of those, six were not detected in X-rays. This suggests that in any survey of polars, around half will be in a low accretion sta…
A CNO Dichotomy among O2 Giant Spectra in the Magellanic Clouds
Walborn, Nolan R.; Massey, Philip; Howarth, Ian D. +4 more
From a survey of the 3400 Å region in the earliest O-type spectra, we have found that two of the four O2 giants observed in the Large Magellanic Cloud have O IV lines there that are stronger than the N IV lines, while the other two have the opposite. A Small Magellanic Cloud counterpart also has N IV stronger than O IV. Inspection of the blue spec…
Multi-wavelength analysis of the dust emission in the Small Magellanic Cloud
Boulanger, F.; Lagache, G.; Cambrésy, L. +2 more
We present an analysis of dust grain emission in the diffuse interstellar medium of the Small Magellanic Cloud (SMC). This study is motivated by the availability of 170 µm ISOPHOT data covering a large part of the SMC, with a resolution making it possible to disentangle the diffuse medium from the star forming regions. After data reduction a…
Comparison of Solar Subsurface Flows Assessed by Ring and Time-Distance Analyses
Gizon, Laurent; Duvall, Thomas L., Jr.; Toomre, Juri +2 more
The solar near-surface shear layer exhibits a rich medley of flows that are now being measured by a variety of local helioseismic techniques. We present comparisons of the horizontal flows obtained with two of these techniques, ring and time-distance analyses, applied to Michelson Doppler Imager (MDI) Dynamics Program data from the years 1998 and …
M31 Globular Cluster X-Ray Sources: XMM-Newton and Chandra Results
Trudolyubov, Sergey; Priedhorsky, William
We present the results of an M31 globular cluster (GC) X-ray source survey, based on the data of XMM-Newton and Chandra observations covering ~6100 arcmin2 of M31. We detected 43 X-ray sources coincident with GC candidates from various optical surveys. The inferred isotropic X-ray luminosities of GC sources lie between ~1035 …
The Stellar Content of the Southern Tail of NGC 4038/4039 and a Revised Distance
Rich, R. Michael; Saviane, Ivo; Hibbard, J. E.
We have used the Hubble Space Telescope and Wide Field Planetary Camera 2 to image the putative tidal dwarf galaxy located at the tip of the Southern tidal tail of NGC 4038/4039, the Antennae. We resolve individual stars and identify two stellar populations. Hundreds of massive stars are present, concentrated into tight OB associations on scales o…
XMM-Newton observations of the σ Ori cluster. I. The complex RGS spectrum of the hot star σ Ori AB
Pallavicini, R.; Franciosini, E.; Sanz-Forcada, J.
We present XMM-Newton observations of the young ({∼} 2{-}5 Myr) cluster around the hot (O9.5V) star σ Orionis AB, aimed at obtaining a high resolution RGS spectrum of the hot star as well as EPIC imaging data for the whole field. We show that the RGS spectrum of σ Ori AB may be contaminated by weaker nearby sources which required the development o…
Inferring of flux rope orientation with the minimum variance analysis technique
Fu, S. Y.; Pu, Z. Y.; Zong, Q. G. +3 more
The accuracy in flux rope orientation inference from both the traditional magnetic-field-based minimum variance analysis (BMVA) technique and the current-based MVA (CMVA) approach is examined. Four different flux rope models are used in the MVA test. It is found that the directions of eigenvectors of MVA are critically dependent on the spacecraft …
Radial Velocity Studies of Close Binary Stars. IX.
Rucinski, Slavek M.; Capobianco, Christopher C.; DeBond, Heide +8 more
Radial velocity measurements and sine-curve fits to the orbital velocity variations are presented for the eighth set of 10 close binary systems: AB And, V402 Aur, V445 Cep, V2082 Cyg, BX Dra, V918 Her, V502 Oph, V1363 Ori, KP Peg, and V335 Peg. Half of the systems (V445 Cep, V2082 Cyg, V918 Her, V1363 Ori, and V335 Peg) were discovered photometric…