Search Publications
Reconstructing the Local Twist of Coronal Magnetic Fields and the Three-Dimensional Shape of the Field Lines from Coronal Loops in Extreme-Ultraviolet and X-Ray Images
Longcope, D. W.; Malanushenko, A.; McKenzie, D. E.
Nonlinear force-free fields are the most general case of force-free fields, but the hardest to model as well. There are numerous methods of computing such fields by extrapolating vector magnetograms from the photosphere, but very few attempts have so far made quantitative use of coronal morphology. We present a method to make such quantitative use…
Hubble Space Telescope Monitoring Reveals a 6.1 Day Period for an Ultraluminous X-Ray Source in NGC 1313
Bregman, Joel N.; McClintock, Jeffrey E.; Liu, Jifeng
Ultraluminous X-ray sources (ULXs) in nearby galaxies have X-ray luminosities of 1039-1041 erg s-1, and are possibly intermediate mass black holes of 102-105 M sun. NGC 1313 X-2 is an extreme ULX with a maximum luminosity of 3 × 1040 erg s-1, and a frequent tar…
Atomic oxygen distribution in the Venus mesosphere from observations of O 2 infrared airglow by VIRTIS-Venus Express
Drossart, Pierre; Bertaux, Jean-Loup; Piccioni, Giuseppe +3 more
This VIRTIS instrument on board Venus Express has collected spectrally resolved images of the Venus nightside limb that show the presence of the (0,0) band of the Δg1→Σg3 infrared atmospheric system of O 2 at 1.27 µm. The emission is produced by three-body recombination of oxygen atoms created by photodissociation of CO 2
High Resolution 36 GHz Imaging of the Supernova Remnant of SN 1987A
Gaensler, B. M.; Manchester, R. N.; Ng, C. -Y. +6 more
The aftermath of supernova (SN) 1987A continues to provide spectacular insights into the interaction between an SN blastwave and its circumstellar environment. We here present 36 GHz observations from the Australia Telescope Compact Array of the radio remnant of SN 1987A. These new images, taken in 2008 April and 2008 October, substantially extend…
Signature of [SiPAH]+ π-complexes in the interstellar medium
Joblin, C.; Simon, A.; Joalland, B. +1 more
Aims: We investigate the presence of silicon atoms adsorbed on the surface of interstellar polycyclic aromatic hydrocarbons (PAHs) to form SiPAH π-complexes.
Methods: We used quantum chemistry calculations to obtain the structural, thermodynamic, and mid-IR properties of neutral and cationic SiPAH π-complexes.
Results: The binding energy w…
The Evolution of the Scatter of the Cosmic Average Color-Magnitude Relation: Demonstrating Consistency with the Ongoing Formation of Elliptical Galaxies
Bell, Eric F.; Barden, Marco; McIntosh, Daniel H. +3 more
We present first measurements of the evolution of the scatter of the cosmic average early-type galaxy color-magnitude relation (CMR) from z = 1 to the present day, finding that it is consistent with models in which galaxies are constantly being added to the red sequence through truncation of star formation in blue cloud galaxies. We used a sample …
Investigation of energetic proton penetration in Titan's atmosphere using the Cassini INCA instrument
Johnson, R. E.; Mitchell, D. G.; Smith, H. T. +1 more
Saturn's largest moon, Titan, provides an interesting opportunity to study how dense atmospheres interact with the surrounding plasma environment. Without an intrinsic magnetic field, this satellite's nitrogen-rich atmosphere is relatively unprotected from plasma interactions. Therefore, the energy-deposition rate is important for understanding ch…
The origin of the supersoft X-ray-optical/UV flux anticorrelation in the symbiotic binary AG Draconis
González-Riestra, R.; Skopal, A.; Sekeráš, M. +1 more
Context: AG Draconis produces a strong supersoft X-ray emission. The X-ray and optical/UV fluxes are in strict anticorrelation throughout the active and quiescent phases.
Aims: We identify the source of the X-ray emission and reveal the nature of the observed flux anticorrelation.
Methods: We used X-ray and UV observations with XMM-Newton,…
Solar Weather Event Modelling and Prediction
Noci, Giancarlo; Messerotti, Mauro; Bothmer, Volker +5 more
Key drivers of solar weather and mid-term solar weather are reviewed by considering a selection of relevant physics- and statistics-based scientific models as well as a selection of related prediction models, in order to provide an updated operational scenario for space weather applications. The characteristics and outcomes of the considered scien…
Variability of CO concentrations in the Venus troposphere from Venus Express/VIRTIS using a Band Ratio Technique
Irwin, P. G. J.; Drossart, P.; Piccioni, G. +5 more
A fast method is presented for deriving the tropospheric CO concentrations in the Venus atmosphere from near-infrared spectra using the night side 2.3 µm window. This is validated using the spectral fitting techniques of Tsang et al. [Tsang, C.C.C., Irwin, P.G.J., Taylor, F.W., Wilson, C.F., Drossart, P., Piccioni, G., de Kok, R., Lee, C., C…