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Observing Mkn 421 with XMM-Newton: The EPIC-PN point of view
Tagliaferri, G.; Ghisellini, G.; Tavecchio, F. +1 more
We present three observations (four exposures) of Mkn 421 performed by XMM-Newton in November and December 2002, concentrating on the EPIC-PN camera data. The X-ray spectra were soft and steepened toward high energies. The source was highly variable and the hardness ratio plots displayed a clear harder-when-stronger correlation. During two complet…
Rapid Penumbral Decay following Three X-Class Solar Flares
Liu, C.; Qiu, J.; Wang, H. +3 more
We show strong evidence that penumbral segments decayed rapidly and permanently right after three X-class solar flares. Two of the three events occurred very recently in NOAA Active Region 10486, an X17 flare on 2003 October 28 and an X10 flare on 2003 October 29. The third X2.3 flare was observed in solar active region NOAA AR 9026 on 2000 June 6…
Spacecraft and Ground Anomalies Related to the October-November 2003 Solar Activity
Webb, David; Allen, Joe
During two weeks in late October and early November 2003, a series of large solar events led to high levels of energetic particles in geospace and produced overlapping large geomagnetic storms on 28-30 October. These storms caused effects ranging from power grid failures to satellite shutdowns. A Japanese satellite was lost completely, the U. S. F…
RHESSI Observations of a Simple Large X-Ray Flare on 2003 November 3
Liu, Wei; Liu, Siming; Jiang, Yan Wei +1 more
We present data analysis and interpretation of a simple X-class flare observed with RHESSI on 2003 November 3. In contrast to other X-class flares observed previously, this flare shows a very simple morphology with well-defined looptop (LT) and footpoint (FP) sources. The almost monotonic upward motion of the LT source and increase in separation o…
Solar Cycle 23: An Anomalous Cycle?
de Toma, Giuliana; White, Oran R.; Chapman, Gary A. +3 more
The latest SOHO VIRGO total solar irradiance (TSI) time series is analyzed using new solar variability measures obtained from full-disk solar images made at the San Fernando Observatory and the Mg II 280 nm index. We discuss the importance of solar cycle 23 as a magnetically simpler cycle and a variant from recent cycles. Our results show the cont…
The Mid-Infrared Luminosity Function of Galaxies in the European Large Area Infrared Space Observatory Survey Southern Fields
Pozzi, F.; Franceschini, A.; Serjeant, S. +7 more
We present the first determination of the 15 µm luminosity function of galaxies from the European Large Area ISO Survey (ELAIS) southern fields. We have adopted a new criterion to separate the quiescent, nonevolving and the starburst, evolving populations based on the ratio of mid-infrared to optical luminosity. Strong evolution is suggested…
Ion loss on Mars caused by the Kelvin Helmholtz instability
Kallio, E.; Barabash, S.; Gunell, H. +8 more
Mars Global Surveyor detected cold electrons above the Martian ionopause, which can be interpreted as detached ionospheric plasma clouds. Similar observations by the Pioneer Venus Orbiter electron temperature probe showed also extreme spatial irregularities of electrons in the form of plasma clouds on Venus, which were explained by the occurrence …
Mid-infrared spectral evidence for a luminous dust enshrouded source in Arp 220
Lutz, D.; Siebenmorgen, R.; Tielens, A. G. G. M. +3 more
We have re-analyzed the 6-12 µm ISO spectrum of the ultra-luminous infrared galaxy Arp 220 with the conclusion that it is not consistent with that of a scaled up version of a typical starburst. Instead, both template fitting with spectra of the galaxies NGC 4418 and M 83 and with dust models suggest that it is best represented by combination…
The Variable Quiescence of Centaurus X-4
Campana, S.; Mereghetti, S.; Stella, L. +2 more
Centaurus X-4 is one of the best-studied low-mass neutron star transients in quiescence. Thanks to XMM-Newton's large throughput, Centaurus X-4 was observed at the highest signal-to-noise ratio ever. This allowed us to discern rapid (>100 s), large (45%+/-7% rms in the 10-4 to 1 Hz range) intensity variability, especially at low ener…
XMM-Newton survey of the Local Group galaxy M 33
Pietsch, W.; Haberl, F.; Hatzidimitriou, D. +3 more
In an XMM-Newton raster observation of the bright Local Group spiral galaxy