| Records |
| Author |
M Chadid and J Vernin and G Preston and C Zalian and C Pouzenc and L Abe and A Agabi and E Aristidi and LY Liu and D, |
| Title |
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Type |
Journal Article |
| Year |
2014 |
Publication |
The Astronomical Journal |
Abbreviated Journal |
Astron. J. (N. Y.) |
| Volume |
148 |
Issue |
5 |
Pages |
88- |
| Keywords |
|
Abstract  |
We present the first detection of multi-shocks propagating through the atmosphere of the Blazhko star S Arae using uninterrupted, accurate optical photometric data collected during one polar night, 150 days from Antarctica at Dome C, with the Photometer AntarctIca eXtinction (PAIX). We acquired 89,736 CCD frames during 323 pulsation cycles and 3 Blazhko cycles. We detected two new light curve properties in the PAIX light curve, ${jump}$ and ${rump}$, which we associated with two new post-maximum shock waves ShPM1 and ShPM2. ${jump}$, lump, ${rump}$, bump, and hump are induced by five shock waves, with different amplitudes and origins, ShPM1, ShPM, ShPM2, ShPM3, and the main shock ShH + He. Correlations between the length of rise time and light amplitude and ShPM3 are monotonous during three Blazhko cycles, but the pulsation curve is double peaked. We discuss the physical mechanisms driving the modulation of these quantities. Finally, we hypothesize that the origin of the Blazhko effect is a dynamical interaction between a multi-shock structure and an outflowing wind in a coronal structure. |
| Programme |
1096 |
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| Series Editor |
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Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1538-3881 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
4906 |
| Permanent link to this record |
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| Author |
Korbinian Sager, Christian Boehm, Laura Ermert, Lion Krischer, Andreas Fichtner |
| Title |
Global-Scale Full-Waveform Ambient Noise Inversion |
Type |
Journal |
| Year |
2020 |
Publication |
Journal of Geophysical Research: Solid Earth |
Abbreviated Journal |
|
| Volume |
125 |
Issue |
4 |
Pages |
e2019JB018644 |
| Keywords |
computational seismology full-waveform inversion global tomography interferometry seismic noise |
| Abstract |
We present the first application of full-waveform ambient noise inversion to observed correlation functions that jointly constrains 3-D Earth structure and heterogeneous noise sources. For this, we model and interpret ambient noise correlations as recordings of correlation wavefields, which completely eliminates the limiting assumptions of Green's function retrieval, such as equipartitioning and homogeneous random noise sources. Our method accounts for seismic wave propagation physics in 3-D heterogeneous and attenuating media and also for the heterogeneous and nonstationary nature of the ambient noise field. Designed as a proof of concept, the study considers long periods from 100 to 300 s, thus focusing on the Earth's hum. Treating correlations as self-consistent observables allows us to make separate measurements on the causal and acausal branches of correlation functions, without any need to choose one of them or form the average. We validate our approach by assessing the quality of the obtained models and by comparing them to previous studies. This work is a step toward the establishment of full-waveform ambient noise inversion as a tomographic technique with the goal to go beyond ambient noise tomography based on Green's function retrieval. |
| Programme |
133 |
| Campaign |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2169-9356 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
7794 |
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| |
| Author |
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| Title |
TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf |
Type |
Journal |
| Year |
2023 |
Publication |
Monthly Notices of the Royal Astronomical Society |
Abbreviated Journal |
|
| Volume |
520 |
Issue |
3 |
Pages |
3649-3668 |
| Keywords |
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| Abstract |
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| Programme |
1066 |
| Campaign |
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| Address |
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Place of Publication |
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Editor |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0035-8711 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8648 |
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| Author |
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| Title |
HIP 33609 b: An Eccentric Brown Dwarf Transiting a V = 7.3 Rapidly Rotating B Star |
Type |
Journal |
| Year |
2023 |
Publication |
The Astronomical Journal |
Abbreviated Journal |
|
| Volume |
165 |
Issue |
6 |
Pages |
268 |
| Keywords |
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| Abstract |
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| Programme |
1066 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1538-3881 |
ISBN |
1538-3881 |
Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8683 |
| Permanent link to this record |
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| |
| Author |
Aristidi E., Agabi K., Fossat E., Azouit M., Martin F., Sadibekova T., Travouillon T., Vernin J. & Ziad A. |
| Title |
Site testing in summer at Dome C, Antarctica. |
Type |
Journal Article |
| Year |
2005 |
Publication |
Astronomy & astrophysics |
Abbreviated Journal |
|
| Volume |
444 |
Issue |
2 |
Pages |
651-659 |
| Keywords |
site testing |
| Abstract |
We present summer site testing results based on DIMM data obtained at Dome C, Antarctica. These data were collected on the bright star Canopus during two 3-months summer campaigns in 2003-2004 and 2004-2005. We performed continuous monitoring of the seeing and the isoplanatic angle in the visible. We found a median seeing of 0.54'' and a median isoplanatic angle of 6.8''. The seeing appears to have a deep minimum around 0.4'' almost every day in late afternoon. |
| Programme |
908 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0004-6361 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
3141 |
| Permanent link to this record |
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| Author |
Hu X G, Liu L T, Kroner C, Sun H P, |
| Title |
Observation of the seismic anisotropy effects on free oscillations below 4 mHz
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Type |
Journal Article |
| Year |
2009 |
Publication |
Journal of Geophysical Research: Solid Earth |
Abbreviated Journal |
J. Geophys. Res. |
| Volume |
114 |
Issue |
B7 |
Pages |
B07301- |
| Keywords |
seismic anisotropy, free oscillations of the earth, mixed-type mode coupling, 7255 Surface waves and free oscillations, 7208 Mantle, 7299 General or miscellaneous, |
| Abstract |
We present observations of significant fundamental spheroidal-toroidal mode coupling at frequencies below 4 mHz in the early part of vertical component records from seismic stations on near-equatorial source-receiver propagation paths after the 26 December 2004 and 28 March 2005 great Sumatra earthquakes. Since the mixed-type coupling induced by rotational Coriolis force are very weak at these selected equatorial-path stations, we investigate what effects mimic the strong Coriolis effects at frequencies below 4 mHz, suggesting that local azimuthal anisotropy in the upper mantle is the most likely explanation for the strong anomalous coupling we observed. In addition, strong anisotropy coupling observed in the frequency band of 14 mHz is always characterized by anomalous small amplitudes of coupled spheroidal modes on the vertical component of seismograph, suggesting that excitation of quasi-toroidal modes by azimuthal anisotropy associates with geometric nodes of fundamental spheroidal modes.
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| Programme |
133 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
57 |
| Permanent link to this record |
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| |
| Author |
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| Title |
What can we learn from HF signal scattered from a discrete arc?
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Type |
Journal Article |
| Year |
2009 |
Publication |
Ann. Geophys. |
Abbreviated Journal |
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| Volume |
27 |
Issue |
5 |
Pages |
1887 -1896 |
| Keywords |
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| Abstract |
We present observations of a discrete southward propagating arc which appeared in the mid-night sector at latitudes equatorward of main substorm activity. The arc observations were made simultaneously by the ALFA (Auroral Light Fine Analysis) optical camera, the SuperDARN-CUTLASS HF radar and the Demeter satellite during a coordinated multi-instrumental campaign conducted at the KEOPS/ESRANGE site in December 2006. The SuperDARN HF signal which is often lost in the regions of strong electron precipitation yields in our case clear backscatter from an isolated arc of weak intensity. Consequently we are able to study arc dynamics, the formation of meso-scale irregularities of the electron density along the arc, compare the arc motion with the convection of surrounding plasma and discuss the contribution of ionospheric ions in the arc erosion and its propagation. |
| Programme |
312;911 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
Bachelor's thesis |
| Publisher |
Copernicus Publications |
Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1432-0576 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
2088 |
| Permanent link to this record |
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| Author |
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| Title |
On the nightglow polarisation for space weather exploration |
Type |
Journal |
| Year |
2020 |
Publication |
Journal of Space Weather and Space Climate |
Abbreviated Journal |
|
| Volume |
10 |
Issue |
|
Pages |
35 |
| Keywords |
polarisation / aurora |
| Abstract |
We present here observations of the polarisation of four auroral lines in the auroral oval and in the polar cusp using a new ground polarimeter called Petit Cru. Our results confirm the already known polarisation of the red line, and show for the first time that the three other lines observed here (namely 557.7 nm, 391.4 nm and 427.8 nm) are polarised as well up to a few percent. We show that in several circumstances, this polarisation is linked to the local magnetic activity and to the state of the ionosphere through the electron density measured with EISCAT. However, we also show that the contribution of light pollution from nearby cities via scattering can not be ignored and can play an important role in polarisation measurements. This series of observations questions the geophysical origin of the polarisation. It also leaves open its relation to the magnetic field orientation and to the state of both the upper atmosphere and the troposphere. |
| Programme |
1026 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2115-7251 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
|
Approved |
yes |
| Call Number |
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Serial |
7796 |
| Permanent link to this record |
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| |
| Author |
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| Title |
Transit timings variations in the three-planet system: TOI-270 |
Type |
Journal |
| Year |
2021 |
Publication |
Monthly Notices of the Royal Astronomical Society |
Abbreviated Journal |
|
| Volume |
510 |
Issue |
4 |
Pages |
5464-5485 |
| Keywords |
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| Abstract |
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| Programme |
1066 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0035-8711 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8413 |
| Permanent link to this record |
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| |
| Author |
Maggi A., Tape C., Chen M., Chao D. & Tromp J. |
| Title |
An automated data-window selection algorithm for adjoint tomography |
Type |
Journal Article |
| Year |
2009 |
Publication |
Geophysical journal international |
Abbreviated Journal |
|
| Volume |
178 |
Issue |
|
Pages |
257-281 |
| Keywords |
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| Abstract |
We present FLEXWIN, an open source algorithm for the automated selection of time windows on pairs of observed and synthetic seismograms. The algorithm was designed specifically to accommodate synthetic seismograms produced from 3-D wavefield simulations, which capture complex phases that do not necessarily exist in 1-D simulations or traditional traveltime curves. Relying on signal processing tools and several user-tuned parameters, the algorithm is able to include these new phases and to maximize the number of measurements made on each seismic record, while avoiding seismic noise. Our motivation is to use the algorithm for iterative tomographic inversions, in which the synthetic seismograms change from one iteration to the next. Hence, automation is needed to handle the volume of measurements and to allow for an increasing number of windows at each model iteration. The algorithm is sufficiently flexible to be adapted to many tomographic applications and seismological scenarios, including those based on synthetics generated from 1-D models. We illustrate the algorithm using data sets from three distinct regions: the entire globe, the Japan subduction zone, and southern California. |
| Programme |
133;906 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0956-540X |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
5163 |
| Permanent link to this record |
