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Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections
Moon, Y. -J.; Lee, Harim; Na, Hyeonock
It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric …
First detection of the 448 GHz H2O transition in space
Rigopoulou, D.; Colina, L.; Martín-Pintado, J. +9 more
We present the first detection of the ortho-H2O 423 - 330 transition at 448 GHz in space. We observed this transition in the local (z = 0.010) luminous infrared (IR) galaxy ESO 320-G030 (IRAS F11506-3851) using the Atacama Large Millimeter/submillimeter Array (ALMA). The water 423 - 330 emissi…
On the Binary Nature of Massive Blue Hypergiants: High-resolution X-Ray Spectroscopy Suggests That Cyg OB2 12 is a Colliding Wind Binary
Hamann, W. -R.; Oskinova, L. M.; Ignace, R. +5 more
The blue hypergiant Cyg OB2 12 (B3Ia+) is a representative member of the class of very massive stars in a poorly understood evolutionary stage. We obtained its high-resolution X-ray spectrum using the Chandra observatory. PoWR model atmospheres were calculated to provide realistic wind opacities and to establish the wind density structu…
The First Detection of a Pulsar with ALMA
de Luca, A.; Possenti, A.; Burgay, M. +8 more
Although there is a general consensus on the fact that pulsars’ radio emission is coherent in nature, whereas the emission from the optical to high-energy γ-rays is due to incoherent processes, it has not been established yet at which wavelengths the transition occurs, which is key information for all emission models of pulsar magnetospheres. Of c…
Gas and dust in the star-forming region ρ Oph A. II. The gas in the PDR and in the dense cores
Liseau, R.; Larsson, B.
Context. The evolution of interstellar clouds of gas and dust establishes the prerequisites for star formation. The pathway to the formation of stars can be studied in regions that have formed stars, but which at the same time also display the earliest phases of stellar evolution, i.e. pre-collapse/collapsing cores (Class -1), protostars (Class 0)…
Quantitative spectroscopy of extreme helium stars Model atmospheres and a non-LTE abundance analysis of BD+10°2179
Butler, K.; Heber, U.; Przybilla, N. +3 more
Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper, we present a detailed quantitative non-LTE spectral analysis for BD+10°2179, a prototype of this rare class of stars, using UV-Visual Echelle Spectrograph and Fiber-fed …
Atmospheric waves and dynamics beneath Jupiter's clouds from radio wavelength observations
de Pater, Imke; Butler, Bryan; Morales-Juberías, Raúl +3 more
We observed Jupiter at wavelengths near 2 cm with the Karl G. Jansky Very Large Array (VLA) in February 2015. These frequencies are mostly sensitive to variations in ammonia abundance and probe between ∼ 0.5 - 2.0 bars of pressure in Jupiter's atmosphere; within and below the visible cloud deck which has its base near 0.7 bars. The resultant obser…
Tidal disruption of stars by super-massive black holes—XMM-Newton highlights and the next decade
Komossa, S.
This article provides a summary of XMM-Newton highlights on stellar tidal disruption events. First found with ROSAT, ongoing and upcoming sky surveys will detect these events in the thousands. In X-rays, tidal disruption events (TDEs) provide us with powerful new probes of accretion physics under extreme conditions and on short timescales and of r…
A high spectral resolution map of the nuclear emitting regions of NGC 7582
Bianchi, S.; Piconcelli, E.; Reeves, J. N. +2 more
We present the results of the spatial and spectral analysis of the deep ( 200 ks) Chandra HETG observation of the changing look AGN NGC 7582. During this long Chandra observation, NGC 7582 was in a highly obscured state. Therefore, we also consider a short ( 24 ks) Suzaku observation, which caught NGC 7582 in a Compton thick state. This allows us …
Extragalactic background light: a measurement at 400 nm using dark cloud shadow*†- I. Low surface brightness spectrophotometry in the area of Lynds 1642
Leinert, Ch.; Väisänen, P.; Lehtinen, K. +2 more
We present the method and observations for the measurement of the Extragalactic Background Light (EBL) utilizing the shadowing effect of a dark cloud. We measure the surface brightness difference between the opaque cloud core and its unobscured surroundings. In the difference the large atmospheric and Zodiacal light components are eliminated and t…