Search Publications
Matched filters for source detection in the Poissonian noise regime
Stewart, I. M.
A procedure is described for estimating an optimum kernel for the detection by convolution of signals among Poissonian noise. The technique is applied to the detection of X-ray point sources in XMM-Newton data, and is shown to yield an improvement in detection sensitivity of up to 60% over the sliding-box method used in the creation of the 1XMM ca…
Assessment of the Martian gravity field at short wavelength with Mars Express
Pätzold, M.; Rosenblatt, P.; Le Maistre, S. +6 more
The gravity part of the Mars Express Radio Science Experiment consists in measuring gravity data near pericenter above selected target areas of geophysical interest. The low altitude of the Mars Express at pericenter (263-329 km) makes it a very sensitive gravity sensor at small wavelengths which can give new constraints on the local structure of …
Striated drifting auroral kilometric radiation bursts: Possible stimulation by upward traveling EMIC waves
Santolik, O.; Menietti, J. D.; Mutel, R. L. +3 more
We investigate waves observed by the Cluster wideband instrument (WBD) during an orbital conjunction with the Polar spacecraft. During this perigee pass, Polar was at the upper extent of the auroral kilometric radiation (AKR) source region in the Southern Hemisphere nightside auroral region. Cluster was located at higher altitude above this region…
GMRT observations of the field of INTEGRAL X-ray sources. II
Durouchoux, P.; Ishwara-Chandra, C. H.; Manchanda, R. +2 more
We conducted low-frequency radio observations with the Giant Metrewave Radio Telescope (GMRT) of the 40 new hard X-ray sources discovered by the INTEGRAL satellite. This survey was conducted in order to study radio emissions from these sources, to provide precise position, and to identify new microquasar candidates. Our observations show that 24 o…
Detailed analysis of low-energy electron streaming in the near-Earth neutral line region during a substorm
Balogh, A.; Fazakerley, A. N.; Klecker, B. +11 more
A synaptic view of Cluster FGM, CIS, EDI, and PEACE observations of the near-Earth neutral line region during 1800 1830 UT on 13 September 2002 is discussed. Associated with the flow reversal and a thin cross-tail current sheet, a clear signature of a quadrupolar magnetic field is observed, which indicates the formation of the Hall current system …
Changing electrical nature of Saturn's rings: Implications for spoke formation
Gurnett, D. A.; Kurth, W. S.; Kaiser, M. L. +2 more
During Cassini's orbit insertion at Saturn, the trajectory took the spacecraft overtop the planet's famed ring system. At this time, the Cassini Radio and Plasma Wave Science (RPWS) instrument obtained unprecedented observations of electron density in the vicinity of the rings. Using this information and a model of photoemission anticipated from t…
Exploration of Venus with the Venera-15 IR Fourier spectrometer and the Venus Express planetary Fourier spectrometer
Ignatiev, N. I.; Zasova, L. V.; Formisano, V. +2 more
The infrared spectrometry of Venus in the range 6-45 µm allows one to sound the middle atmosphere of Venus in the altitude range 55-100 km and its cloud layer. This experiment was carried out onboard the Soviet automatic interplanetary Venera-15 station, where the Fourier spectrometer for this spectral range was installed. The measurements h…
Multi-Satellite Observations of ULF Waves
Volwerk, Martin
Single spacecraft observations of ULF waves can only give limited information on the properties of these waves. One can determine e.g., polarization and use minimum variance analysis to obtain an indication of the propagation direction. To obtain more and more accurate information, it is necessary to use multi-spacecraft data. With the arrival of …
Compact X-ray binaries in and out of core collapsed globulars
Grindlay, Jonathan E.
We review new Chandra and HST observations of the core collapsed cluster NGC 6397 as a guide to understanding the compact binary (CB) populations in core collapse globulars. New cataclysmic variables (CVs) and main sequence chromospherically active binaries (ABs) have been identified, enabling a larger sample for comparison of the Lx, F…
Philae (Rosetta Lander): Experiment status after commissioning
Rosenbauer, H.; Biele, J.; Bibring, J. P. +2 more
Being successfully launched on March 2, 2004, ESA's cornerstone mission "ROSETTA" (originally planned to be launched in January 2003 to comet Wirtanen) is en route. It will also bring the 100 kg Lander "Philae" with a scientific payload of 26.7 kg to the surface of comet 67P/Churyumov-Gerasimenko. After a first scientific sequence in 2014 it will …