Search Publications
SuperModel Analysis of A1246 and J255: On the Evolution of Galaxy Clusters from High to Low Entropy States
Lapi, A.; Fusco-Femiano, R.
We present an analysis of high-quality X-ray data out to the virial radius for the two galaxy clusters A1246 and GMBCG J255.34805+64.23661 (J255) by means of our entropy-based SuperModel. For A1246 we find that the spherically averaged entropy profile of the intracluster medium (ICM) progressively flattens outward, and that a nonthermal pressure c…
The Flybys of Asteroids 2867 Steins, 21 Lutetia, and 4179 Toutatis
Barucci, M. A.; Thomas, N.; Fulchignoni, M. +2 more
Three flybys of asteroids have occurred in the period between 2008 and 2012. (2867) Šteins and (21) Lutetia have been observed by the European Space Agency's Rosetta spacecraft, and (4179) Toutatis was observed by the Chinese National Space Agency's Chang'e-2. The properties of these three bodies are very different from other asteroids visited to …
New Horizons: Long-range Kuiper Belt targets observed by the Hubble Space Telescope
Stern, S. A.; Weaver, H. A.; Buie, M. W. +4 more
We report on Hubble Space Telescope (HST) observations of three Kuiper Belt Objects (KBOs), discovered in our dedicated ground-based search campaign, that are candidates for long-range observations from the New Horizons spacecraft: 2011 JY31, 2011 HZ102, and 2013 LU35. Astrometry with HST enables both current and f…
Evolution of Kelvin-Helmholtz instability at Venus in the presence of the parallel magnetic field
Zhang, T. L.; Cao, J. B.; Fu, H. S. +2 more
Two-dimensional MHD simulations were performed to study the evolution of the Kelvin-Helmholtz (KH) instability at the Venusian ionopause in response to the strong flow shear in presence of the in-plane magnetic field parallel to the flow direction. The physical behavior of the KH instability as well as the triggering and occurrence conditions for …
The use of the power density for identifying reconnection regions
Gunell, H.; Hamrin, M.; Vaivads, A. +2 more
In the vicinity of magnetic reconnection, magnetic energy is transferred into kinetic energy. A reconnection region hence corresponds to a load, and it should manifest itself as large and positive values of the power density, E·J ≫ 0, where E is the electric field and J the current density. In this article we analyze Cluster plasma sheet data from…
An obscured narrow-line Seyfert 1 galaxy candidate, Mrk 1388 with nonthermal jets
Doi, Akihiro
Mrk 1388 has an unusual Seyfert nucleus that shows narrow emission-line components without broad emission-line ones, but shows a strong featureless continuum and strong iron-forbidden, high-ionization emission lines. The apparent coexistence of type-1/2 characteristics is potentially attributed to a heavily obscured broad-line region or to an inte…
A Gemini/GMOS Study of Intermediate Luminosity Early-type Virgo Cluster Galaxies. I. Globular Cluster and Stellar Kinematics
Jordán, Andrés; Liu, Chengze; Zhang, Hong-xin +10 more
We present a kinematic analysis of the globular cluster (GC) systems and diffuse stellar light of four intermediate luminosity (sub-L*) early-type galaxies in the Virgo cluster based on Gemini Multi-Object Spectrographs (GMOS) data. Our galaxy sample is fainter (-23.8\lt {{M}K}\lt -22.7) than most previous studies, nearly doubling the n…
Titan's Upper Atmosphere from Cassini/UVIS Solar Occultations
Koskinen, Tommi T.; Yelle, Roger V.; Capalbo, Fernando J. +1 more
Titan’s atmosphere is composed mainly of molecular nitrogen, methane being the principal trace gas. From the analysis of 8 solar occultations measured by the Extreme Ultraviolet channel of the Ultraviolet Imaging Spectrograph (UVIS) on board Cassini, we derived vertical profiles of N2 in the range 1100-1600 km and vertical profiles of C…
On the in-flight calibration plans of modern x-ray observatories
Petre, Robert; Guainazzi, Matteo; Audard, Marc +5 more
We present an overview of the set of celestial sources used for in-flight calibration of x-ray detectors by past and operational missions. We show the rationale behind their choice as a guideline for future missions aiming at optimizing the critical early phases of their science operations.
Formation of Pores Associated with the Inflow of Moving Magnetic Features
Zhang, Hongqi; Yang, Zhiliang; Li, Xiaobo
We investigate the formation of pores in NOAA AR 10930 associated with the inflow of moving magnetic features (MMFs) using simultaneous Hinode/Solar Optical Telescope filtergrams and magnetograms. The main results are outlined as follows: (1) the existence of MMFs around pores is a fairly common phenomenon. Around the four innate and one residue p…