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X-Ray Observations of Solar Long-Duration Flares
Phillips, K. J. H.; Harra, L. K.; Feldman, U.
Yohkoh X-ray observations during the several-hour decay of six large solar flares show that the main emitting region is in the form of a bright loop-top source whose spatial extent well after the impulsive stage explains most of the broadening of S XV and Ca XIX X-ray lines, which would otherwise imply nonthermal velocities of 100 km s-1
XMM-Newton Observation of IC 310 in the Outer Region of the Perseus Cluster of Galaxies
Ishida, Manabu; Sato, Kosuke; Ohashi, Takaya +3 more
We present results from an XMM-Newton observation of the head-tail radio galaxy IC 310 located in the southwest region of the Perseus cluster. The spectrum is well fitted by an absorbed power-law model with a photon index of 2.50 ± 0.02 without significant absorption excess. The X-ray image shows a point-like emission at IC 310 without any sign of…
Electron densities in EUV coronal bright points
Doyle, J. G.; Del Zanna, G.; Ugarte-Urra, I.
Electron density measurements of six coronal bright points have been obtained using line ratio diagnostics of four ions in the temperature range 1.3-2.0 × 106 K. The results suggest that BP plasma has more similarities to active region plasma than to quiet Sun plasma. Nevertheless, they do not show the exact same behaviour: the increase…
Irregular Mass Transfer in the Polars VV Puppis and V393 Pavonis during the Low State
Pandel, Dirk; Córdova, France A.
The polars VV Pup and V393 Pav were observed with XMM-Newton during states of low accretion with peak X-ray luminosities of ~1×1030 and ~1×1031 ergs s-1, respectively. In both polars, accretion onto the white dwarf was extremely irregular, and the accretion rate varied by more than 1 order of magnitude on timescale…
Rotation Rates of Particles in Saturn's Rings
Ohtsuki, Keiji
Rotational states of particles in Saturn's rings are not directly observable but have been inferred from spacecraft and ground-based observations of their thermal emission. A temperature contrast between night- and daysides of particles in Saturn's C ring during crossing of the planetary shadow has been detected and interpreted as indicating the p…
XMM-Newton and VLT observations of the afterglow of GRB 040827
Covino, S.; D'Avanzo, P.; Caraveo, P. A. +13 more
The field of the Gamma-Ray Burst GRB 040827 was observed with XMM-Newton and with the ESO/VLT starting 6 and 12 h after the burst, respectively. A fading X-ray afterglow is clearly detected with the XMM-Newton/EPIC instrument, with a time decay t-δ, with δ=1.41±0.10. Its spectrum is well described by a power law (photon index Γ=2.3±0.1)…
On the origin and configuration of the 20 March 2003 interplanetary shock and magnetic cloud at 1 AU
Richardson, I. G.; Lepping, R. P.; Martin, S. F. +1 more
On 20 March 2003, a forward shock was observed in the near-Earth solar wind, followed 8 hours later by an interplanetary magnetic cloud (IMC), in a configuration having several uncommon features: Both were parts of a 38-hour interval containing transient solar outflows that occurred in an extended high-speed stream from a Y-shaped extension of the…
Nuclear Properties of Nearby Spiral Galaxies from Hubble Space Telescope NICMOS Imaging and STIS Spectroscopy
Marconi, A.; Capetti, A.; Carollo, C. M. +16 more
We investigate the central regions of 23 spiral galaxies using Space Telescope Imaging Spectrograph (STIS) spectroscopy and archival Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) imaging. The sample is taken from our program to determine the masses of central massive black holes (MBHs) in 54 nearby spiral galaxies. Stars are likely t…
Abundances in planetary nebulae: Mz 3
Pottasch, S. R.; Surendiranath, R.
ISO spectra of the bipolar planetary nebula
The near-UV pulse profile and spectrum of the pulsar PSR B0656+14
Sollerman, J.; Lundqvist, P.; Shibanov, Yu. A. +2 more
We have observed the middle-aged pulsar PSR B0656+14 with the prism and the NUV MAMA detector of the Space Telescope Imaging Spectrograph (STIS) to measure the pulsar spectrum and periodic pulsations in the near-ultraviolet (NUV). The pulsations are clearly detected, double-peaked and very similar to the optical pulse profile. The NUV pulsed fract…