Search Publications
Advection and dispersal of small magnetic elements in the very quiet Sun
Asensio Ramos, A.; Martínez González, M. J.; Manso Sainz, R.
We track small magnetic structures on very quiet regions (internetwork) of the Sun. We follow the footpoints of small-scale magnetic loops that appear on the photosphere at granular scales using spectropolarimetric and magnetographic data obtained with Hinode. We find two different regimes for their wanderings. Within granules (where they appear),…
The nature of nuclear Hα emission in LINERs
González-Martín, O.; Márquez, I.; Masegosa, J. +1 more
To get insight into the nature of the ionized gas in the nuclear region of LINERs, we performed a study of HST Hα imaging of 32 LINERs. The main conclusion from this analysis is that, for the large majority of LINERs (84%), an unresolved nuclear source has been identified along with extended emission with equivalent sizes ranging from a few tens t…
Relationship between multiple type II solar radio bursts and CME observed by STEREO/SECCHI
Cho, K. -S.; Moon, Y. -J.; Shanmugaraju, A. +3 more
Aims: Two or more type II bursts are occasionally observed in close time sequence during solar eruptions, which are known as multiple type II bursts. The origin of the successive burst has been interpreted in terms of coronal mass ejections (CMEs) and/or flares. Detailed investigations of the relationship between CMEs and the bursts enable us…
Collapsed, uncollapsed, and hidden magnetic flux on the quiet Sun
Stenflo, J. O.
Since the first applications of the Stokes V line ratio in the early 1970s and the Hanle depolarization effect in the early 1980s we have had a dualistic view of quiet-Sun magnetism: intermittent kG flux tubes surrounded by an ocean of turbulent fields with strengths of order 10-100 G. There has been the concern that this dualism could be an artef…
HESS J1943+213: a candidate extreme BL Lacertae object
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +199 more
Context. The H.E.S.S. Cherenkov telescope array has been surveying the Galactic plane for new VHE (>100 GeV) gamma-ray sources.
Aims: We report on a newly detected point-like source, HESS J1943+213. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts.
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On the degeneracy of the tidal Love number k2 in multi-layer planetary models: application to Saturn and GJ 436b
Stevenson, D. J.; Nettelmann, N.; Kramm, U. +1 more
Context. In order to accurately model giant planets, a whole set of observational constraints is needed. As the conventional constraints for extrasolar planets like mass, radius, and temperature allow for a large number of acceptable models, a new planetary parameter is desirable in order to further constrain planetary models. Such a parameter may…
Statistical properties of superactive regions during solar cycles 19-23
Zhang, J.; Wang, J. X.; Chen, A. Q. +2 more
Context. Each solar activity cycle is characterized by a small number of superactive regions (SARs) that produce the most violent of space weather events with the greatest disastrous influence on our living environment.
Aims: We aim to re-parameterize the SARs and study the latitudinal and longitudinal distributions of SARs.
Methods: We …
Herschel observations of EXtra-Ordinary Sources (HEXOS): Methanol as a probe of physical conditions in Orion KL
Menten, K. M.; Martin, P. G.; Murphy, J. A. +45 more
We have examined methanol emission from Orion KL withthe Herschel/HIFI instrument, and detected two methanol bands centered at 524 GHz and 1061 GHz. The 524 GHz methanol band (observed in HIFI band 1a) is dominated by the isolated ΔJ = 0, K = -4 → -3, vt = 0 Q branch, and includes 25 E-type and 2 A-type transitions. The 1061 GHz methano…
First detection of hydrogen isocyanide (HNC) in Titan's atmosphere
Lara, L. M.; Hartogh, P.; Lellouch, E. +7 more
We report on the first identification of hydrogen isocyanide (HNC) in Titan's atmosphere, from observations using the HIFI instrument on the Herschel Space Observatory. An emission line from the HNC J = 6 → 5 rotational transition at 543.897 GHz was measured in Titan on June 14 and December 31, 2010. Radiative transfer modeling indicates that the …
Monitoring a high-amplitude δ Scuti star for 152 days: discovery of 12 additional modes and modulation effects in the light curve of CoRoT 101155310
Auvergne, M.; Baudin, F.; Poretti, E. +12 more
Aims: The detection of small-amplitude nonradial modes in high-amplitude δ Sct (HADS) variables has been very elusive until at least five of them were detected in the light curve of V974 Oph obtained from ground-based observations. The combination of radial and nonradial modes has a high asteroseismic potential, thanks to the strong constrain…