Search Publications
XMM-Newton investigations of the Lambda Orionis star-forming region (XILO). I. The young cluster Collinder 69
Bayo, A.; Huélamo, N.; Barrado, D. +6 more
Context. This is the first paper of a series devoted to the Lambda Orionis star-forming region, Orion's Head, from the X-ray perspective. Our final aim is to provide a comprehensive view of this complex region, which includes several distinct associations and dark clouds.
Aims: We aim to uncover the population of the central, young star clust…
A detailed spectral study of GRB 041219A and its host galaxy
Covino, S.; Götz, D.; Esposito, P. +4 more
GRB 041219A is one of the longest and brightest gamma-ray bursts (GRBs) ever observed. It was discovered by the INTEGRAL satellite, and thanks to a precursor happening about 300 s before the bulk of the burst, ground-based telescopes were able to catch the rarely observed prompt emission in the optical and in the near-infrared bands.
Here we …Proton cyclotron wave generation mechanisms upstream of Venus
Zhang, T. L.; Volwerk, M.; Mazelle, C. +3 more
Long-term observations of proton cyclotron waves in the upstream region of Venus raise the question of under which general solar wind conditions these waves are generated and maintained. The waves are characterized by their occurrence at the local proton cyclotron frequency and left-hand polarization, both in the spacecraft frame. Magnetometer dat…
Shallow Radar (SHARAD), pedestal craters, and the lost Martian layers: Initial assessments
Head, James W.; Kadish, Seth J.; Smrekar, Suzanne E. +5 more
Since their discovery, Martian pedestal craters have been interpreted as remnants of layers that were once regionally extensive but have since been mostly removed. Pedestals span from subkilometer to hundreds of kilometers, but their thickness is less than ∼500 m. Except for a small equatorial concentration in the Medusae Fossae Formation, the nea…
O+ outflow channels around Venus controlled by directions of the interplanetary magnetic field: Observations of high energy O+ ions around the terminator
Barabash, S.; Futaana, Y.; Yamauchi, M. +5 more
Using the plasma and the magnetic field data measured by the ASPERA-4 (Analyzer of Space Plasma and Energetic Atoms) and the magnetometer (MAG) onboard Venus Express between June 2006 and December 2008, positions of high energy O+ fluxes (>100 eV) near the Venus terminator are examined for two different interplanetary magnetic field …
Magnetic states of the ionosphere of Venus observed by Venus Express
Barabash, S.; Woch, J.; Fränz, M. +4 more
Strong ultraviolet radiation from the Sun ionizes the upper atmosphere of Venus, creating a dense ionosphere on the dayside of the planet. In contrast to Earth, the ionosphere of Venus is not protected against the solar wind by a magnetic field. However, the interaction between charged ionospheric particles and the solar wind dynamic and magnetic …
Intrinsic Shape of Star-forming BzK Galaxies at z ~ 2 in GOODS-N
Kajisawa, Masaru; Ohta, Kouji; Yabe, Kiyoto +2 more
We study the structure of star-forming galaxies at z ~ 2 in a Great Observatories Origins Deep Survey North field selected as star-forming BzK (sBzK) galaxies down to K AB < 24.0 mag. Among 1029 sBzK galaxies, 551 galaxies (54%) show a single component in the Advanced Camera for Survey (ACS)/F850LP image obtained with the Hubble Spac…
XMM-Newton Observations Reveal Very High X-ray Luminosity from the Carbon-rich Wolf-Rayet Star WR 48a
Skinner, Stephen L.; Zhekov, Svetozar A.; Gagné, Marc
We present XMM-Newton observations of the dusty Wolf-Rayet (W-R) star WR 48a. This is the first detection of this object in X-rays. The XMM-Newton EPIC spectra are heavily absorbed and the presence of numerous strong emission lines indicates a thermal origin of the WR 48a X-ray emission, with dominant temperature components at kT cool ≈…
Mirror Mode Expansion in Planetary Magnetosheaths: Bohm-like Diffusion
Tsurutani, Bruce T.; Hasegawa, Akira
Observed scale sizes of mirror modes in planetary magnetosheaths tend to be equal or larger than those that correspond to the maximum growth rate of the mirror instability: 9 ρp (proton gyroradius). These phenomena can be accounted for by introducing a diffusion process (Bohm) that shifts the spectra to lower wave numbers as the mode co…
Flare occurrence and the spatial distribution of the magnetic helicity flux
Romano, P.; Zuccarello, F.
Context. The accumulation of magnetic helicity via emergence of new magnetic flux and/or shearing photospheric motions is considered an important tool for understanding the processes that lead to eruptive phenomena.
Aims: We highlight a specific aspect of the magnetic helicity accumulation, providing new observational evidence of the role pla…