Search Publications
Validated helioseismic inversions for 3D vector flows
Hanasoge, S. M.; Gizon, L.; Švanda, M. +1 more
Context. According to time-distance helioseismology, information about internal fluid motions is encoded in the travel times of solar waves. The inverse problem consists of inferring three-dimensional vector flows from a set of travel-time measurements. While only few tests of the inversions have been done, it is known that the retrieval of the sm…
Continuous upflows and sporadic downflows observed in active regions
Peter, H.; Solanki, S. K.; Curdt, W. +1 more
Aims: We present a study of the temporal evolution of coronal loops in active regions and its implications for the dynamics in coronal loops.
Methods: We analyzed images of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) at multiple temperatures to detect apparent motions in the coronal loops.
Results:…
Turbulent and fast motions of H2 gas in active galactic nuclei
Combes, F.; Dasyra, K. M.
Querying the Spitzer archive for optically-selected active galactic nuclei (AGN) observed in high-resolution-mode spectroscopy, we identified radio and/or interacting galaxies with highly turbulent motions of H2 gas at a temperature of a few hundred Kelvin. Unlike all other AGN that have unresolved H2 line profiles at a spect…
Spectroscopic evidence for helicity in explosive events
Curdt, W.; Tian, H.
Aims: We report spectroscopic observations in support of a novel view of transition region explosive events, observations that lend empirical evidence that at least in some cases explosive events may be nothing else but spinning narrow spicule-like structures.
Methods: Our spectra of textbook explosive events with simultaneous Doppler fl…
GOODS-Herschel: a population of 24 µm dropout sources at z < 2
Magnelli, B.; Lutz, D.; Altieri, B. +25 more
Using extremely deep PACS 100- and 160 µm Herschel data from the GOODS-Herschel program, we identify 21 infrared bright galaxies previously missed in the deepest 24 µm surveys performed by Spitzer/MIPS. These MIPS dropouts are predominantly found in two redshift bins, centred at z ~ 0.4 and ~1.3. Their S100/S24 fl…
Wide-field VLBA observations of the Chandra deep field South
Deller, A.; Lenc, E.; Morgan, J. +7 more
Context. Wide-field surveys are a commonly-used method for studying thousands of objects simultaneously, to investigate, e.g., the joint evolution of star-forming galaxies and active galactic nuclei. Very long baseline interferometry (VLBI) observations can yield valuable input for such studies because they are able to identify AGN unambiguously i…
Overview of an extensive multi-wavelength study of GX 339-4 during the 2010 outburst
D'Avanzo, P.; Goldoni, P.; Rahoui, F. +8 more
Context. The microquasar GX 339-4 experienced a new outburst in 2010: it was observed simultaneously at various wavelengths from radio up to soft γ-rays. We focus on observations that are quasi-simultaneous with those made with the INTEGRAL and RXTE satellites: these were collected in 2010 March-April during our INTEGRAL target of opportunity prog…
Twelve-hour spikes from the Crab Pevatron
Walter, R.; Ferrigno, C.; Balbo, M. +1 more
Aims: The
Methods: We divide the available data into three different sets, corres…
Dynamics and plasma properties of an X-ray jet from SUMER, EIS, XRT, and EUVI A & B simultaneous observations
Madjarska, M. S.
Context. Small-scale transient phenomena in the quiet Sun are believed to play an important role in coronal heating and solar wind generation. One of them, called “X-ray jet”, is the subject of our study.
Aims: We intend to investigate the dynamics, evolution, and physical properties of this phenomenon.
Methods: We combine multi-instrume…
Low abundance, strong features: window-dressing crystalline forsterite in the disk wall of HD 100546
Waters, L. B. F. M.; Dominik, C.; Henning, Th. +10 more
Context. Forsterite is one of the crystalline dust species that is often observed in protoplanetary disks and solar system comets. Being absent in the interstellar medium, it must be produced during the disk lifetime. It can therefore serve as a tracer of dust processing and disk evolution, which can lead to a better understanding of the physical …