Search Publications
Observation of repeated intense near-Earth reconnection on closed field lines with Cluster, Double Star, and other spacecraft
Sauvaud, J. -A.; Zhang, T. L.; Glassmeier, K. -H. +14 more
We report strong repeated magnetic reconnection pulses that occurred deep inside closed plasma sheet flux tubes at r ≤ 14Re. They have been observed with a fortuitous spacecraft constellation during three consecutive turbulent magnetic dipolarizations, accompanied by localized auroral brightenings near the equatorward edge of a wide auroral oval. …
Time-Distance Helioseismology: Sensitivity of f-mode Travel Times to Flows
Birch, A. C.; Duvall, T. L., Jr.; Gizon, L. +1 more
Time-distance helioseismology has shown that f-mode travel times contain information about horizontal flows in the Sun. The purpose of this study is to provide a simple interpretation of these travel times. We study the interaction of surface gravity waves with horizontal flows in an incompressible, plane-parallel solar atmosphere. We show that fo…
South-West extension of the hard X-ray emission from the Coma cluster
Eckert, D.; Produit, N.; Courvoisier, T. J. -L. +1 more
Aims:We explore the morphology of hard (18-30 keV) X-ray emission from the Coma cluster of galaxies.
Methods: We analyse a deep (1.1 Ms) observation of the Coma cluster with the ISGRI imager on board the INTEGRAL satellite.
Results: We show that the source extension in the North-East to South-West (SW) direction ( 17^prime) significantly e…
Bulges and Disklike Components in the Host Galaxies of Low-Redshift 3CR Sources: A Near-Infrared View of Their Radial Brightness Profiles
Marchesini, Danilo; Chiaberge, Marco; Capetti, Alessandro +3 more
We analyze the near-infrared luminosity profiles and photometric parameters of the host galaxies of 3CR radio sources with z<0.3, to investigate their physical nature. Our sample includes 82 galaxies, of which 22 (27%) are FR Is and 60 (73%) are FR IIs. Using near-infrared data taken both with NICMOS on board the Hubble Space Telescope and from…
Magnetic Interaction: An Erupting Filament and a Remote Coronal Hole
Yang, Liheng; Shen, Yuandeng; Jiang, Yunchun +1 more
For the first time, we present a rare observation of direct magnetic interaction between an erupting filament and a coronal hole (CH). The small active region filament obliquely erupted toward the CH getting in the way, met and interacted with it, and then was deflected back. The erupting filament thus underwent a distinct to-and-fro motion in the…
Spectral Diagnostics of the Magnetic Field Orientation in a Prominence Observed with SOHO/SUMER
Heinzel, P.; Anzer, U.; Schmieder, B. +1 more
During several campaigns focused on prominences we have obtained coordinated spectral observations from the ground and from space. The SOHO/SUMER spectrometer allows us to observe, among others, the whole Lyman series of hydrogen, while the Hα line was observed by the MSDP spectrograph at the VTT. For the Lyman lines, non-LTE radiative-transfer co…
Coronal mass ejections: Solar cycle aspects
St. Cyr, O. C.; Cremades, Hebe
Research in the area of coronal mass ejections (CMEs) is now mature, since their discovery coincided with the first coronagraph that was flown in space in 1971. However, the continuity of space coronagraphs and similar instruments has allowed the detection and measurement of CMEs over almost three consecutive solar cycles. Their importance in the …
Long-term infrared variability of the UX Ori-type star SV Cep
Prusti, T.; Ábrahám, P.; Dullemond, C. P. +1 more
We investigate the long-term optical-infrared variability of SVCep and explain it in the context of an existing UX Ori (UXOR) model. A 25-month monitoring programme was completed with the Infrared Space Observatory in the 3.3-100 µm wavelength range. Following a careful data reduction, the infrared light curves were correlated with the varia…
A Quadrupolar Preplanetary Nebula: IRAS 19475+3119
Sahai, Raghvendra; Sánchez Contreras, Carmen; Morris, Mark +1 more
Our imaging of the preplanetary nebula IRAS 19475+3119 (hereafter I19475) at 0.43 and 0.6 µm with HST reveals a quadrupolar nebula of size about 10.5''×4.7'', with two bipolar elongated lobes emanating from the center of the nebula. One of the bipolar lobes shows detailed point-symmetric structure with respect to the ce…
Coronal and Chromospheric Dimmings during a Halo-Type CME Event
Yang, Liheng; Jiang, Yunchun; Li, Kejun +1 more
We present complementary solar observations of a filament eruption occurring in association with a halo-type coronal mass ejection (CME) on 2006 July 6 in AR 10898. This eruption was followed by an M2.5 flare and has led to the formation of a pair of dimmings, observed in Hα, over network patterns in regions of opposite magnetic polarities located…