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Enhanced X-ray variability from V1647 Ori, the young star in outburst illuminating McNeil's Nebula
Hamaguchi, K.; Grosso, N.; Kastner, J. H. +5 more
We report a 38 ks X-ray observation of McNeil's Nebula obtained with XMM-Newton on 2004 April 4. V1647 Ori, the young star in outburst illuminating McNeil's Nebula, is detected with XMM-Newton and appears variable in X-rays. We investigate the hardness ratio variability and time variations of the event energy distribution with quantile analysis, a…
Multialtitude Observations of a Coronal Jet during the Third Whole Sun Month Campaign
Mason, H. E.; Thompson, B. J.; Raymond, J. C. +11 more
On 1999 August 26, a coronal jet occurred at the northwest limb near a sigmoid active region (AR 8668) that was the target for a joint observation plan (SOHO joint observing program 106) during the third Whole Sun Month Campaign. This jet was observed by several instruments at the limb (SOHO/CDS, SOHO/EIT, TRACE, and Mauna Loa Solar Observatory CH…
Jupiter's cyclones and anticyclones vorticity from Voyager and Galileo images
Sánchez-Lavega, A.; Legarreta, J.
We have measured the internal velocity field in jovian synoptic-scale cyclones and anticyclones by tracking cloud elements in very high spatial resolution images obtained by the Voyager 1 and 2 (in 1979) and Galileo (1996-2000) spacecrafts. In total we have studied 24 different closed vortices (6 cyclones, 18 anticyclones) spanning a latitude rang…
On the formation of the He I 10 830 Å line in a flaring atmosphere
Ding, M. D.; Li, H.; Fang, C.
We explore the formation of the He i 10 830 Å line in a flaring atmosphere, with special attention to the nonthermal effects of an electron beam. Using non-LTE calculations we obtain the line profiles from different model atmospheres. Without the nonthermal effects, the line changes from weak absorption in a cool atmosphere to emission in a hot an…
Temporal deconvolution of the hydrogen coma. II. Pre- and post-perihelion activity of Comet Hyakutake (1996 B2)
Bertaux, J. -L.; Combi, M. R.; Mäkinen, J. T. T. +1 more
Comet 1996 B2 (Hyakutake) displayed strong evidence for break-up, with a prominent antisunward dust spike and fragments traveling antisunward for many days after an eruptive event in late March 1996. Because of its high orbital inclination and rapid southward motion after perihelion, its post-perihelion activity was not well monitored from the gro…
Correlation Heights of the Sources of Solar Ultraviolet Emission Lines in a Quiet-Sun Region
Wilhelm, Klaus; Marsch, Eckart; Wang, Jing-Xiu +4 more
The radiance and Doppler-velocity maps of the emission lines of Si II, C IV, and Ne VIII obtained in a quiet region of the Sun by SUMER (Solar Ultraviolet Measurements of Emitted Radiation) are correlated with the vertical component, Bz, of the magnetic field vector as extrapolated, by means of a force-free field model, from the photosp…
Faint Fuzzies and the Formation of Lenticular Galaxies
Brodie, Jean; Burkert, Andreas; Larsen, Soeren
We investigate the dynamical state of a new class of extended star clusters known as ``faint fuzzies,'' which were discovered in two nearby S0 galaxies, NGC 1023 and NGC 3384. It is shown that the faint fuzzies of NGC 1023 lie in a fast-rotating ringlike structure within the galactic disk with mean radius of 5 kpc, rotational velocity of 200 km s<…
Spectral energy distribution of the metagalactic ionizing radiation field from QSO absorption spectra
Levshakov, S. A.; Agafonova, I. I.; Centurión, M. +1 more
A computational procedure is presented to estimate the spectral shape of the ionizing background between 1 and 10 Ryd by analyzing optically thin absorption systems in the spectra of high redshift quasars. The procedure is based on the response surface methodology from the theory of experimental design. The shape of the recovered UV background at …
Outburst of the X-ray Transient SAX J1818.6-1703 Detected by the INTEGRAL Observatory in September 2003
Sunyaev, R. A.; Grebenev, S. A.
During the observation of the Galactic-center field by the INTEGRAL observatory on September 9, 2003, the IBIS/ISGRI gamma-ray telescope detected a short (several-hours-long) intense (∼380 mCrab at the peak) outburst of hard radiation from the X-ray transient SAX J1818.6-1703. Previously, this source was observed only once in 1998 during a similar…
Integral Field Spectroscopy of the Central Regions of 3C 120: Evidence of a Past Merging Event
Christensen, L.; García-Lorenzo, B.; Mediavilla, E. +2 more
Optical integral field spectroscopy (IFS), combined with Hubble Space Telescope (HST) WFPC imaging, was used to characterize the central regions of the Seyfert 1 radio galaxy 3C 120. We carried out the analysis of the data, deriving intensity maps of different emission lines and the continua at different wavelengths from the observed spectra. Appl…