Search Publications
The Subaru/XMM-Newton Deep Survey (SXDS). V. Optically Faint Variable Object Survey
Ouchi, Masami; Wang, Lifan; Ueda, Yoshihiro +19 more
We present our survey for optically faint variable objects using multiepoch (8-10 epochs over 2-4 years) i'-band imaging data obtained with Subaru Suprime-Cam over 0.918 deg2 in the Subaru/XMM-Newton Deep Field (SXDF). We found 1040 optically variable objects by image subtraction for all the combinations of images at different epochs. T…
A Hot Microflare Observed with RHESSI and Hinode
Milligan, Ryan O.
RHESSI and Hinode observations of a GOES B-class flare are combined to investigate the origin of 15 MK plasma. The absence of any detectable hard X-ray emission coupled with weak blueshifted emission lines (indicating upward velocities averaging only 14 km s-1) suggests that this was a result of direct heating in the corona, as opposed …
Hubble Space Telescope STIS Spectroscopy of Long-Period Dwarf Novae in Quiescence
Szkody, Paula; Sion, Edward M.; Godon, Patrick +5 more
We present the results of a synthetic spectral analysis of HST STIS spectra of five long-period dwarf novae obtained during their quiescence to determine the properties of their white dwarfs, which are little known for systems above the CV period gap. The five systems, TU Men, BD Pav, SS Aur, TT Crt, and V442 Cen, were observed as part of an HST S…
The Evolution of Circumstellar Disks in Ophiuchus Binaries
Jensen, E. L. N.; Patience, J.; Akeson, R. L.
Four Ophiuchus binaries, two Class I systems and two Class II systems, with separations of ~450-1100 AU, were observed with the Owens Valley Radio Observatory (OVRO) millimeter interferometer. In each system, the 3 mm continuum maps show dust emission at the location of the primary star, but no emission at the position of the secondary. This resul…
A Hard X-Ray View of Two Distant VHE Blazars: 1ES 1101-232 and 1ES 1553+113
Reimer, A.; Reimer, O.; Costamante, L. +2 more
TeV blazars are known as prominent nonthermal emitters across the entire electromagnetic spectrum with their photon power peaking in the X-ray and TeV bands. If distant, absorption of γ-ray photons by the extragalactic background light (EBL) alters the intrinsic TeV spectral shape, thereby affecting the overall interpretation. Suzaku observations …
Orbital Parameters and Chemical Composition of Four White Dwarfs in Post-Common-Envelope Binaries
Vennes, Stéphane; Lanz, Thierry; Chayer, Pierre +2 more
We present FUSE observations of the hot white dwarfs in the post-common-envelope binaries Feige 24, EUVE J0720-317, BPM 6502, and EUVE J2013+400. The spectra show numerous photospheric absorption lines, which trace the white dwarf orbital motion. We report the detection of C III, O VI, P V, and Si IV in the spectra of Feige 24, EUVE J0720-317, and…
Inferring Photospheric Velocity Fields Using a Combination of Minimum Energy Fit, Local Correlation Tracking, and Doppler Velocity
Longcope, D. W.; Ravindra, B.; Abbett, W. P.
The minimum energy fit (MEF), a velocity inversion technique, infers all components of the photospheric velocity that are consistent with the induction equation. From the set of consistent velocity fields, it selects the smallest overall flow speed by minimizing a kinetic energy functional. If partial velocity information is available from other m…
A Study of the ρ Ophiuchi Cloud: Mapping the Distribution and the Motions of Interstellar Gas
Welty, Daniel E.; Snow, Theodore P.; Destree, Joshua D.
Guest Investigator results from Hipparcos, combined with high-resolution optical spectra obtained with the Anglo-Australian Observatory, Kitt Peak National Observatory, and McDonald Observatory, are used to create a three-dimensional map of the stars and several interstellar gas components in the ρ Oph cloud complex. Many principal gas components …
A Comparison among Solar Diameter Measurements Carried Out from the Ground and outside Earth's Atmosphere
Thuillier, G.; Djafer, D.; Sofia, S.
The solar diameter has been measured since the 17th century, using different methods and instruments, and without a clear strategy of measurement, which could explain the lack of coherence between the results obtained. The present study confirms that the discrepancies between solar diameter measurements are mostly due to differences in instrumenta…
UV and Radio Observations of the Coronal Shock Associated with the 2002 July 23 Coronal Mass Ejection Event
Mancuso, S.; Avetta, D.
We report on the analysis of a fast coronal mass ejection (CME)-driven shock observed on 2002 July 23 with the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO). The CME was first detected in white light by the Large Angle and Spectrometric Coronagraph Experiment (LASCO), and shock-associated type I…