Search Publications
A Study of the Orientation of Interplanetary Magnetic Clouds and Solar Filaments
Wang, Yuming; Wang, Jingxiu; Wang, S. +2 more
As a kind of eruptive phenomenon associated with coronal mass ejections (CMEs), solar eruptive filaments are thought to be parallel to the axis of surrounding arcade coronal magnetic fields that erupt and develop into interplanetary magnetic clouds (MCs). By investigating three events from 2000 August, 2003 October, and 2003 November, we estimate …
Optical spectroscopy of X-Mega targets in the Carina nebula - VI. FO15: a new O-type double-lined eclipsing binary
Barbá, R.; Morrell, N. I.; Niemela, V. S. +3 more
We report the discovery of a new O-type double-lined spectroscopic binary with a short orbital period of 1.4 d. We find the primary component of this binary, FO15, to have an approximate spectral type O5.5Vz, i.e. a zero-age main-sequence (ZAMS) star. The secondary appears to be of spectral type O9.5V. We have performed a numerical model fit to th…
The first detection of propane on Saturn
Bézard, Bruno; Moses, Julianne I.; Lacy, John H. +3 more
We report the first detection of propane, C 3H 8, in Saturn's stratosphere. Observations taken on September 8, 2002 UT at NASA's IRTF using TEXES, show multiple emission lines due to the 748 cm -1ν band of C 3H 8. Using a line-by-line radiative transfer code, we are able to fit the data by sca…
Photometric Calibration of the Lasco-C3 Coronagraph Using Stars
Thernisien, A. F.; Howard, R. A.; Wang, D. +1 more
The LASCO-C3 coronagraph on SOHO, launched in December 1995, has been collecting images of the corona and background star fields in a regular manner since 1996. This instrument contains a number of broadband filters with various passbands in the range between 400 and 1100 nm. The filter used most often has been the Clear filter (400-900 nm) but th…
XMM-Newton Observation of Diffuse Gas and Low-Mass X-Ray Binaries in the Elliptical Galaxy NGC 4649 (M60)
Sarazin, Craig L.; Irwin, Jimmy A.; Randall, Scott W.
We present an XMM-Newton X-ray observation of the X-ray-bright E2 elliptical galaxy NGC 4649. In addition to bright diffuse emission, we resolve 158 discrete sources, ~50 of which are likely to be LMXBs associated with NGC 4649. We find evidence for variability in three sources between this observation and a previous Chandra observation. Additiona…
Are short γ-ray bursts collimated? GRB 050709, a flare but no break
Sollerman, J.; Watson, D.; Fynbo, J. P. U. +5 more
Context: .From the small sample of afterglow lightcurves of short duration γ-ray bursts (GRBs), the decays are rapid, roughly following a power-law in time. It has been assumed that the afterglow emission in short GRBs is collimated in jets in the same way as in long GRBs.
Aims: .An achromatic break in a short GRB afterglow lightcurve would th…
Spectral Evolution of the Luminous Blue Variable NGC 2363-V1. I. Observations and Qualitative Analysis of the Ongoing Giant Eruption
Drissen, Laurent; Crowther, Paul A.; Petit, Véronique
We describe the spectroscopic evolution of the extragalactic luminous blue variable NGC 2363-V1 from 1997 to 2004. Photometrically, this star has gradually faded by 0.3 mag in the V band over this period, while spectra obtained with the Hubble Space Telescope show dramatic changes: a gradual strengthening of the UV flux (a fourfold increase at 120…
Remarkable Disk and Off-Nuclear Starburst Activity in the Tadpole Galaxy as revealed by the Spitzer Space Telescope
Berta, S.; Rodighiero, G.; Hatziminaoglou, E. +20 more
We present ground-based optical and Spitzer Space Telescope infrared imaging observations of the interacting galaxy UGC 10214, the Tadpole galaxy (z=0.0310), focusing on the star formation activity in the nuclear, disk, spiral arms, and tidal tail regions. The ground-based optical data set spans a wavelength range between 0.3 and 0.8 µm, the…
Spectral States of the X-Ray Binary IGR J17091-3624 Observed by INTEGRAL and RXTE
Capitanio, F.; Bird, A. J.; Ubertini, P. +6 more
IGR J17091-3624 was discovered in 2003 April by IBIS, the gamma-ray imager on board the INTEGRAL satellite, during its Galactic Center Deep Exposure program. The source was initially detectable only in the 40-100 keV range but after 2 days was also detected in the 15-40 keV range. Its flux had by then increased to 40 and 25 mcrab in the 15-40 and …
Ultracompact Blue Dwarf Galaxies: Hubble Space Telescope Imaging and Stellar Population Analysis
Somerville, Rachel S.; Windhorst, Rogier A.; Vacca, William D. +3 more
We present deep Hubble Space Telescope (HST) Advanced Camera for Surveys/High Resolution Channel U-, narrow-V-, and I-band images of nine ``ultracompact'' blue dwarf galaxies (UCBDs) selected from the Sloan Digital Sky Survey (SDSS). We define UCBDs as local (z<0.01) star-forming galaxies having angular diameters less than 6" and physical diame…