Astronomy & Astrophysics

All Figures

$\begin{figure} \par {\includegraphics[width=8.8cm,clip]{0815fig1.eps} } \end{figure}$ Figure 1: A post-eruptive arcade imaged by TRACE at 195 Å on 04-Nov.-2003 at 22:35 UT.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=14.4cm,clip]{0815fig2.eps} \end{figure}$ Figure 2: Top panel: running difference images taken by EIT 195 Å on 12-Sep.-2000. The first two images show the erupting prominence (EP) event and consequent post-eruptive arcade (PEA) formation in the southern hemisphere near CM. Points 1 and 2 represent the start and end points of the PEA. The last figure reveals the dimming of the arcade. Bottom panel: LASCO/C2 images showing the evolution of the associated CME in white-light. LE denotes the leading edge of the CME and EP the erupting prominence. In all figures, north is up and west is towards the right. The speed of the CME in the plane of the sky was 1550 km s^-1 at PA 220.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8.1cm,clip]{0815fig3.eps} } \end{figure}$ Figure 3: LASCO C2/C3 h-t diagram for the CME detected on 12-Sep.-2000, around 12:30 UT. The solid triangle marks the estimated CME onset time at 1 solar radii and the solid circle represents the identified onset time of the PEA based on EIT 195 Å images. The h-t diagram was taken from the CME catalogue at http://cdaw.gsfc.nasa.gov/CME_list/.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8.1cm,clip]{0815fig4.ps} } \end{figure}$ Figure 4: Distribution of PEAs in heliographic longitude in bins of 10 degrees as identified in EIT 195 Å images from 1997 to 2002. The portions of the bars represented as spotted areas represent those PEAs for which no white-light CME had been detected by LASCO/C2.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=14cm,clip]{0815fig5.ps} \end{figure}$ Figure 5: Top panel: the first image shows a running difference image taken by EIT at 195 Å on 17-Feb.-2000 displaying the PEA that had formed in the southern hemisphere. The second and third images show that a filament (F) disappeared from this solar region based on H ${\alpha }$ observations taken on 17 and 18 February 2000 (courtesy Paris/Meudon Observatory). Bottom panel: the associated halo CME on February 17, 2000 as detected by LASCO/C2 around 21:30 UT. The speed of the CME was 600 km s^-1 at PA 196.
Open with DEXTER

In the text

$\begin{figure} \includegraphics[angle=90,width=15cm,clip]{0815fig6.eps} \end{figure}$ Figure 6: Multi-wavelengths observations for the source region of the 17-Feb.-2000 PEA event around 21:30 UT. Top to bottom: First panel: EIT 195 Å images taken at 20:12 UT, 20:24 UT and 20:36 UT on February 17, 2000 showing the pre-eruption configuration of the halo CME detected later by LASCO and the initial phase of the arcade formation. Second panel: Yohkoh/SXT images taken at 20:03 UT, 20:23 UT and 21:23 UT on the same day showing the brightening of an S-shaped sigmoid in the S-hemisphere in the CME source region. Third panel: H ${\alpha }$ observations taken on 16, 17 and 18 February 2000 showing that a filament had disappeared from the corresponding source region. Fourth panel: MDI magnetograms taken at 12:53 UT on February 16, 16:43 UT and 21:20 UT on February 17, showing the photospheric magnetic field structure of the CME's source region.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=14.5cm,clip]{0815fig7.ps} \end{figure}$ Figure 7: Left to right: zoomed view of the post-eruptive arcade (PEA) observed by EIT at 195 Å on 15-Apr.-2001 at 05:12 UT followed by two H- alpha images taken on 14 and 15 April showing the position of the corresponding disappearing filament (F) on the solar disk.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8.2cm,clip]{0815fig8.ps} } \end{figure}$ Figure 8: GOES 8 X-ray plots for the CME and PEA events on February 9, 2000 ( top) and 6 July, 2000 ( bottom). The approximate onset times of the CMEs and PEAs are labeled.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0815fig9.ps} \end{figure}$ Figure 9: YOHKOH/SXT image taken on 25-Jan.-1998 at 15:54 UT showing the coronal brightening (CB) that was detected on the NE part of the solar disk and the corresponding post-eruptive arcade (PEA) observed by EIT at 195 Å at 17:53 UT.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8cm,clip]{0815fig10.ps} }\end{figure}$ Figure 10: Frequency distribution of the lifetimes of the identified PEAs during 1997-2002 based on SOHO/EIT 195 Å observations in bins of 2 h. The average value for the lifetime was 7 h.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=13.5cm,clip]{0815fig11.ps} \end{figure}$ Figure 11: Carrington synoptic map representing the positions of all identified PEAs during 1997-2002 based on the analysis of SOHO/EIT 195 Å observations.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8cm,clip]{0815fig12.ps} }\end{figure}$ Figure 12: Frequency distribution showing the heliographic lengths of PEAs identified from SOHO/EIT 195 Å images during 1997-2002 in bins of 5 $^\circ$ . The average length of the identified PEAs was 15 $^\circ$ .
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8.4cm,clip]{0815fig13.ps} }\end{figure}$ Figure 13: Variation of PEA lengths with heliographic latitude during 1997-2002. The data points represent the latitude for the midpoint of the PEA axes. Note that no events were identified above 60 $^\circ$ . The straight lines represent the fitted latitudinal trends in both solar hemispheres in the range 20 to 40 degree latitude, with: $L_{\rm N} (\deg) = 2.9 (b -17.1)$ and $L_{\rm S}(\deg)= - 1.6 (b + 13.4)$ , with b being the heliographic latitude of the mid point of a PEA axis. Positive values of the latitude correspond to the northern hemisphere.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=18cm,clip]{0815fig14.eps} }\end{figure}$ Figure 14: SOHO/MDI Carrington synoptic charts for rotations 1928 a) in 1997 and 1963 b) in 2000 and identified source regions of nine post-eruptive arcades (PEAs), marked by solid and dashed lines. In the synoptic charts, white colors represent areas of positive magnetic polarity, black colors those of negative polarity. Note that in the North the leading areas reveal positive magnetic polarities in this cycle and vice versa in the South. The solid and dashed lines represent the individual PEA axes. Case i) and j) indicates a linear shaped PEA. A PEA located in between two bipolar regions is labeled as k) and a case untypical for the dominant polarity in the northern hemisphere in cycle 23 as l) polarity configuration.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8.1cm,clip]{0815fig15.eps} } \end{figure}$ Figure 15: Sketch showing the possible pre-eruption field configuration of PEAs forming along neutral lines/filament sites in single bipolar regions (A) and in between pairs of them (B). The pre-eruption configuration is adapted from Tandberg-Hanssen (1974).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=14cm,clip]{0815fig16.ps} \end{figure}$ Figure 16: Carrington synoptic charts of the heliographic positions of post-eruptive arcades identified during 1997-2002 for which the magnetic polarities of the source regions were identified from MDI synoptic charts. The colors at the equatorward ends of the PEAs denote the magnetic polarity to the West of the individual polarity inversion line, with the red color being assigned to the positive magnetic polarity and the blue color assigned to the negative one.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=15.6cm,clip]{0815fig17.ps} \end{figure}$ Figure 17: a) Total number of PEAs identified in the Sun's northern and southern hemispheres (solid lines) during 1997-2002 based on SOHO/EIT 195 Å observations displayed together with the number of events with positive and negative magnetic polarities (dashed lines) to the West of the neutral line in northern and southern hemisphere respectively. The dotted lines represent the number of events with reversed polarities in both hemispheres. b) Same notation as in a), but with PEAs exhibiting quadrupolar-like (PEAs that formed in between pairs of BPRs) photospheric field source regions removed. Note that no events were recorded by EIT during the SOHO recovery phase in the second half of 1998.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8.6cm,clip]{0815fig18.ps} }\end{figure}$ Figure 18: Variation of the heliographic latitude of post-eruptive arcades in solar cycle 23 from 1997 to 2002. The straight line represents fits for the Sun's northern (positive latitudes) and southern (negative latitudes) hemisphere. Note that no events were detected above 60 $^\circ$ latitude.
Open with DEXTER

In the text

$\begin{figure} \par {\includegraphics[width=8.8cm,clip]{0815fig1.eps} } \end{figure}$	Figure 1: A post-eruptive arcade imaged by TRACE at 195 Å on 04-Nov.-2003 at 22:35 UT.
Open with DEXTER

$\begin{figure} \par {\includegraphics[width=8.1cm,clip]{0815fig3.eps} } \end{figure}$	Figure 3: LASCO C2/C3 h-t diagram for the CME detected on 12-Sep.-2000, around 12:30 UT. The solid triangle marks the estimated CME onset time at 1 solar radii and the solid circle represents the identified onset time of the PEA based on EIT 195 Å images. The h-t diagram was taken from the CME catalogue at http://cdaw.gsfc.nasa.gov/CME_list/.
Open with DEXTER

$\begin{figure} \par {\includegraphics[width=8.1cm,clip]{0815fig4.ps} } \end{figure}$	Figure 4: Distribution of PEAs in heliographic longitude in bins of 10 degrees as identified in EIT 195 Å images from 1997 to 2002. The portions of the bars represented as spotted areas represent those PEAs for which no white-light CME had been detected by LASCO/C2.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=14.5cm,clip]{0815fig7.ps} \end{figure}$	Figure 7: Left to right: zoomed view of the post-eruptive arcade (PEA) observed by EIT at 195 Å on 15-Apr.-2001 at 05:12 UT followed by two H- alpha images taken on 14 and 15 April showing the position of the corresponding disappearing filament (F) on the solar disk.
Open with DEXTER

$\begin{figure} \par {\includegraphics[width=8.2cm,clip]{0815fig8.ps} } \end{figure}$	Figure 8: GOES 8 X-ray plots for the CME and PEA events on February 9, 2000 ( top) and 6 July, 2000 ( bottom). The approximate onset times of the CMEs and PEAs are labeled.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0815fig9.ps} \end{figure}$	Figure 9: YOHKOH/SXT image taken on 25-Jan.-1998 at 15:54 UT showing the coronal brightening (CB) that was detected on the NE part of the solar disk and the corresponding post-eruptive arcade (PEA) observed by EIT at 195 Å at 17:53 UT.
Open with DEXTER

$\begin{figure} \par {\includegraphics[width=8cm,clip]{0815fig10.ps} }\end{figure}$	Figure 10: Frequency distribution of the lifetimes of the identified PEAs during 1997-2002 based on SOHO/EIT 195 Å observations in bins of 2 h. The average value for the lifetime was 7 h.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=13.5cm,clip]{0815fig11.ps} \end{figure}$	Figure 11: Carrington synoptic map representing the positions of all identified PEAs during 1997-2002 based on the analysis of SOHO/EIT 195 Å observations.
Open with DEXTER

$\begin{figure} \par {\includegraphics[width=8cm,clip]{0815fig12.ps} }\end{figure}$	Figure 12: Frequency distribution showing the heliographic lengths of PEAs identified from SOHO/EIT 195 Å images during 1997-2002 in bins of 5 $^\circ$ . The average length of the identified PEAs was 15 $^\circ$ .
Open with DEXTER

$\begin{figure} \par {\includegraphics[width=8.1cm,clip]{0815fig15.eps} } \end{figure}$	Figure 15: Sketch showing the possible pre-eruption field configuration of PEAs forming along neutral lines/filament sites in single bipolar regions (A) and in between pairs of them (B). The pre-eruption configuration is adapted from Tandberg-Hanssen (1974).
Open with DEXTER

$\begin{figure} \par {\includegraphics[width=8.6cm,clip]{0815fig18.ps} }\end{figure}$	Figure 18: Variation of the heliographic latitude of post-eruptive arcades in solar cycle 23 from 1997 to 2002. The straight line represents fits for the Sun's northern (positive latitudes) and southern (negative latitudes) hemisphere. Note that no events were detected above 60 $^\circ$ latitude.
Open with DEXTER