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Effective area calibration of the reflection grating spectrometers of XMM-Newton. I. X-ray spectroscopy of the Crab nebula
Kaastra, J. S.; Costantini, E.; de Vries, C. P. +1 more
Context: The Crab nebula and pulsar have been widely used as a calibration source for X-ray instruments. The in-flight effective area calibration of the Reflection Grating Spectrometers (RGS) of XMM-Newton depend upon the availability of reliable calibration sources.
Aims: We investigate how the absolute effective area calibration of RGS can b…
3D Evolution of a Filament Disappearance Event Observed by STEREO
Schmieder, B.; Chandra, R.; Venkatakrishnan, P. +2 more
A filament disappearance event was observed on 22 May 2008 during our recent campaign JOP 178. The filament, situated in the Southern Hemisphere, showed sinistral chirality consistent with the hemispheric rule. The event was well observed by several observatories, in particular by THEMIS. One day, before the disappearance, Hα observations showed u…
Hierarchical star formation: stars and stellar clusters in the Gould Belt
Alfaro, E. J.; Cabrera-Caño, J.; Elias, F.
We perform a study of the spatial and kinematical distribution of young open clusters in the solar neighbourhood, discerning between bound clusters and transient stellar condensations within our sample. Then, we discriminate between Gould Belt (GB) and local Galactic disc (LGD) members, using our previous estimate of the structural parameters of b…
The EROS2 search for microlensing events towards the spiral arms: the complete seven season results
Couchot, F.; Perdereau, O.; Andersen, J. +37 more
Aims: The EROS-2 project has been designed to search for microlensing events towards any dense stellar field. The densest parts of the Galactic spiral arms have been monitored to maximize the microlensing signal expected from the stars of the Galactic disk and bulge.
Methods: 12.9 million stars have been monitored during 7 seasons towards 4 di…
The Relationship between Coronal Dimming and Coronal Mass Ejection Properties
Biesecker, D. A.; Reinard, A. A.
Coronal dimmings are closely related to the footpoints of coronal mass ejections (CMEs) and, as such, offer information about CME origins and evolution. In this paper, we investigate the relationship between CME and dimming properties. In particular, we compare CME quantities for events with and without associated dimmings. We find that dimming-as…
The low-mass initial mass function in the young cluster NGC6611
van Loon, J. Th.; Jeffries, R. D.; Oliveira, J. M.
NGC6611 is the massive young cluster (2-3Myr) that ionizes the Eagle Nebula. We present very deep photometric observations of the central region of NGC6611 obtained with the Hubble Space Telescope and the following filters: ACS/WFC F775W and F850LP and NIC2 F110W and F160W, loosely equivalent to ground-based IZJH filters. This survey reaches down …
Time-dependent global MHD simulations of Cassini T32 flyby: From magnetosphere to magnetosheath
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +10 more
When the Cassini spacecraft flew by Titan on 13 June 2007, at 13.6 Saturn local time, Titan was directly observed to be outside Saturn's magnetopause. Cassini observations showed dramatic changes of magnetic field orientation as well as other plasma flow parameters during the inbound and outbound segments. In this paper, we study Titan's ionospher…
Reliability of prediction of the magnetosheath BZ component from interplanetary magnetic field observations
Němeček, Z.; Gutynska, O.; Šafránková, J. +2 more
In the present statistical study, we discuss a probability of simultaneous observations of the same sign of the magnetic field BZ component in the solar wind and magnetosheath. The analysis is based on 5 min data from four spacecraft (Interball-1, IMP 8, Cluster, and THEMIS) operating in different phases of the solar cycle in the magnet…
Deep Chandra Monitoring Observations of NGC 4278: Catalog of Source Properties
Zezas, A.; Gallagher, J.; King, A. R. +11 more
We present the properties of the discrete X-ray sources detected in our monitoring program of the globular cluster (GC) rich elliptical galaxy, NGC 4278, observed with Chandra ACIS-S in six separate pointings, resulting in a co-added exposure of 458 ks. From this deep observation, 236 sources have been detected within the region overlapped by all …
Suzaku and Multi-Wavelength Observations of OJ 287 during the Periodic Optical Outburst in 2007
Isobe, Naoki; Kohno, Kotaro; Shimajiri, Yoshito +153 more
Suzaku observations of the blazar OJ 287 were performed in 2007 April 10-13 and November 7-9. They correspond to a quiescent and a flaring state, respectively. The X-ray spectra of the source can be well-described with single power-law models in both exposures. The derived X-ray photon index and the flux density at 1 keV were found to be Γ = 1.65±…