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The evolving accretion disc in the black hole X-ray transient XTE J1859+226
Chaty, S.; Cui, W.; Shrader, C. R. +2 more
We present HST, RXTE, and UKIRT observations of the broad-band spectra of the black hole X-ray transient XTE J1859+226 during the decline from its 1999-2000 outburst. Our UV spectra define the 2175-Å interstellar absorption feature very well and based on its strength we estimate E(B-V)=0.58+/-0.12. Hence we deredden our spectra and follow the evol…
An observational study of a magneto-acoustic wave in the solar corona
Mathioudakis, M.; Keenan, F. P.; Phillips, K. J. H. +5 more
The Solar Eclipse Corona Imaging System (SECIS) observed a strong 6-s oscillation in an active region coronal loop, during the 1999 August 11 total solar eclipse. In the present paper we show that this oscillation is associated with a fast-mode magneto-acoustic wave that travels through the loop apex with a velocity of 2100 km s-1. We u…
Discovery of X-ray emission from the protostellar jet L1551 IRS5 (HH 154)
Micela, G.; Favata, F.; Sciortino, S. +2 more
We have for the first time detected X-ray emission associated with a protostellar jet, on the jet emanating from the L1551 IRS5 protostar. The IRS5 protostar is hidden behind a very large absorbing column density, making the direct observation of the jet's emission possible. The observed X-ray emission is likely associated with the shock ``working…
GRB 011121: A Massive Star Progenitor
Wieringa, M. H.; Axelrod, T. S.; Frontera, F. +29 more
Of the cosmological gamma-ray bursts, GRB 011121 has the lowest redshift, z=0.36. More importantly, the multicolor excess in the afterglow detected in the Hubble Space Telescope (HST) light curves is compelling observational evidence of an underlying supernova. Here we present near-infrared and radio observations of the afterglow, and from our com…
Three LINERs under the Chandra X-Ray Microscope
Moran, Edward C.; Shields, Joseph C.; Eracleous, Michael +1 more
We use observations of three galaxies hosting low-ionization nuclear emission-line regions (LINERs; NGC 404, NGC 4736, and NGC 4579) with the Chandra X-Ray Observatory to study their power sources. We find very diverse properties within this small group: NGC 404 has an X-ray faint nucleus with a soft, thermal spectrum; NGC 4736 harbors a plethora …
Dust and the spectral energy distribution of the OH/IR star OH 127.8+0.0: Evidence for circumstellar metallic iron
Waters, L. B. F. M.; de Koter, A.; Tielens, A. G. G. M. +2 more
We present a fit to the spectral energy distribution of
Flare Activity and Magnetic Helicity Injection by Photospheric Horizontal Motions
Moon, Y. -J.; Wang, Haimin; Yurchyshyn, Vasyl +5 more
We present observational evidence that the occurrence of homologous flares in an active region is physically related to the injection of magnetic helicity by horizontal photospheric motions. We have analyzed a set of 1 minute cadence magnetograms of NOAA AR 8100 taken over a period of 6.5 hr by the Michelson Doppler Imager on board the Solar and H…
Saturn: Search for a missing water source
Johnson, R. E.; Jurac, S.; Richardson, J. D. +3 more
The origin of the large hydroxyl radical (OH) cloud near the inner moons of Saturn, indicative of a surprisingly large water-vapor source, has represented a puzzle since its discovery in 1992. A new set of Hubble Space Telescope measurements is used to constrain the OH spatial densities and to pinpoint the source region. Our model indicates that t…
Photospheric Motions and Coronal Mass Ejection Productivity
Zhang, H.; Nindos, A.
Shearing motions have been frequently used in MHD simulations of coronal mass ejection (CME) initiation but have hardly been reported from observations of CME-producing regions. In this Letter, we investigate whether the bulk of magnetic helicity carried away from the Sun by CMEs comes from helicity injected to the corona by such motions or by eme…
Nanodiamonds around HD 97048 and Elias 1
Tielens, A. G. G. M.; Waelkens, C.; Van Kerckhoven, C.
We present an analysis of ISO-SWS observations of the Herbig Ae/Be stars HD 97048 and Elias 1. Besides the well-known family of IR emission bands at 3.3, 6.2, ``7.7'', 8.6 and 11.2 mu m these objects show strong, peculiar emission features at 3.43 and 3.53 mu m. The latter two features show pronounced substructure which is very similar in the two …