Search Publications
Vortices in Saturn's Northern Hemisphere (2008-2015) observed by Cassini ISS
West, Robert A.; Porco, Carolyn C.; Baines, Kevin H. +12 more
We use observations from the Imaging Science Subsystem on Cassini to create maps of Saturn's Northern Hemisphere (NH) from 2008 to 2015, a time period including a seasonal transition (i.e., spring equinox in 2009) and the 2010 giant storm. The processed maps are used to investigate vortices in the NH during the period of 2008-2015. All recorded vo…
Quasi periodic oscillations in active galactic nuclei
Kara, E.; Fabian, A.; Middleton, M. +3 more
Quasi-periodic oscillations (QPOs) are coherent peaks of variability power observed in the X-ray power spectra (PSDs) of stellar mass X-ray binaries (XRBs). A scale invariance of the accretion process implies they should be present in the active galactic nuclei. The first robust detection was a ∼ 1 h periodicity in the Seyfert galaxy RE J1034+396 …
Lifecycle of a large-scale polar coronal pseudostreamer/cavity system
Auchère, Frédéric; Rachmeler, Laurel; Seaton, Daniel +1 more
We report on an exceptional large-scale coronal pseudostreamer/cavity system in the southern polar region of the solar corona that was visible for approximately a year starting in February 2014. It is unusual to see such a large closed-field structure embedded within the open polar coronal hole. We investigate this structure to document its format…
The H I supershell GS 118+01-44 and its role in the interstellar medium
Noriega-Crespo, A.; Cichowolski, S.; Arnal, E. M. +3 more
Aims: We carry out a multiwavelength study to characterize the H I supershell designated GS 118+01-44, and to analyse its possible origin.
Methods: A multiwavelength study has been carried out to study the supershell and its environs. We performed an analysis of the H I, CO, radio continuum, and infrared emission distributions.
Resu…
Physical properties of Galactic Planck cold cores revealed by the Hi-GAL survey
Testi, L.; Molinari, S.; Zahorecz, S. +3 more
Context. Previous studies of the initial conditions of massive star and star cluster formation have mainly targeted infrared-dark clouds (or IRDCs) toward the inner Galaxy. This is because IRDCs were first detected in absorption against the bright mid-infrared (IR) background of the inner Galaxy, requiring a favorable location to be observed. By s…
Van Allen Probes, THEMIS, GOES, and Cluster observations of EMIC waves, ULF pulsations, and an electron flux dropout
Green, J. C.; Santolík, O.; Carr, C. +9 more
We examined an electron flux dropout during the 12-14 November 2012 geomagnetic storm using observations from seven spacecraft: the two Van Allen Probes, Time History of Events and Macroscale Interactions during Substorms (THEMIS)-A (P5), Cluster 2, and Geostationary Operational Environmental Satellites (GOES) 13, 14, and 15. The electron fluxes f…
NGC 2440 : A morpho-kinematical model
Costa, R. D. D.; Lago, P. J. A.
The 3D structure and position-velocity (P-V) diagrams of NGC 2440 were modeled aiming to describe the morphology of this object, specially its core. High resolution spectra, HST images and P-V diagrams were used to reproduce the 3D structure of the nebula using SHAPE. The best model for the nebula is a torus torn apart in three pieces by interacti…
A systematic search for lensed high-redshift galaxies in HST images of MACS clusters
Richard, J.; Ebeling, H.; Repp, A.
We present the results of a 135-arcmin2 search for high-redshift galaxies lensed by 29 clusters from the MAssive Cluster and extended MAssive Cluster Surveys. We use relatively shallow images obtained with the Hubble Space Telescope in four passbands, namely, F606W, F814W, F110W, and F140W. We identify 130 F814W dropouts as candidates f…
A Star-forming Ring around κ Ori 250 pc from the Sun
Megeath, S. T.; Pillitteri, I.; Wolk, S. J.
X-rays are a powerful probe of activity in early stages of star formation. They allow us to identify young stars even after they have lost the IR signatures of circumstellar disks and provide constraints on their distance. Here, we report on XMM-Newton observations that detect 121 young stellar objects (YSOs) in two fields between L1641 S and κ Or…
DR Tauri: Temporal variability of the brightness distribution in the potential planet-forming region
Wolf, S.; Ratzka, Th.; Brunngräber, R. +1 more
Aims: We investigate the variability of the brightness distribution and the changing density structure of the protoplanetary disk around DR Tau, a classical T Tauri star. DR Tau is known for its peculiar variations from the ultraviolet (UV) to the mid-infrared (MIR). Our goal is to constrain the temporal variation of the disk structure based …