Search Publications
The Spectral and Temporal Properties of Transient Sources in Early-type Galaxies
Zezas, A.; King, A. R.; Pellegrini, S. +8 more
We report the spectral and temporal variability properties of 18 candidate transient (TC) and potential transient (PTC) sources detected in deep multi-epoch Chandra observation of the nearby elliptical galaxies, NGC 3379, NGC 4278, and NGC 4697. Only one source can be identified with a background counterpart, leaving 17 TCs + PTCs in the galaxies.…
The brightening of Saturn's F ring
Nicholson, Philip D.; Hedman, Matthew M.; Showalter, Mark R. +5 more
Image photometry reveals that the F ring is approximately twice as bright during the Cassini tour as it was during the Voyager flybys of 1980 and 1981. It is also three times as wide and has a higher integrated optical depth. We have performed photometric measurements of more than 4800 images of Saturn's F ring taken over a 5-year period with Cass…
Magnetised Kelvin-Helmholtz instability in the intermediate regime between subsonic and supersonic regimes
Henri, P.; Califano, F.; Pegoraro, F. +1 more
The understanding of the dynamics at play at the Earth's Magnetopause, the boundary separating the Earth's magnetosphere and the solar wind plasmas, is of primary importance for space plasma modeling. We focus our attention on the low latitude flank of the magnetosphere where the velocity shear between the magnetosheath and the magnetospheric plas…
First Ultraviolet Reflectance Spectra of Pluto and Charon by the Hubble Space Telescope Cosmic Origins Spectrograph: Detection of Absorption Features and Evidence for Temporal Change
Stern, S. A.; Spencer, J. R.; Cunningham, N. J. +2 more
We have observed the mid-UV spectra of both Pluto and its large satellite, Charon, at two rotational epochs using the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) in 2010. These are the first HST/COS measurements of Pluto and Charon. Here we describe the observations and our reduction of them, and present the albedo spectra, aver…
Globular Cluster Systems of Spiral and S0 Galaxies: Results from WIYN Imaging of NGC 1023, NGC 1055, NGC 7332, and NGC 7339
Rhode, Katherine L.; Young, Michael D.; Dowell, Jessica L.
We present results from a study of the globular cluster (GC) systems of four spiral and S0 galaxies imaged as part of an ongoing wide-field survey of the GC systems of giant galaxies. The target galaxies—the SB0 galaxy NGC 1023, the SBb galaxy NGC 1055, and an isolated pair comprised of the Sbc galaxy NGC 7339 and the S0 galaxy NGC 7332—were obser…
A multiwavelength survey of NGC 6752: X-ray counterparts, two new dwarf novae and a core-collapsed radial profile
Maccarone, T. J.; Knigge, C.; Sarajedini, A. +6 more
We present the results of a multiwavelength (far-ultraviolet to I band) survey of the stellar populations of the globular cluster NGC 6752, using Space Telescope Imaging Spectrograph (STIS), Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. We have confirmed that two previously identified catacly…
Rotational periods and evolutionary models for subgiant stars observed by CoRoT⋆
do Nascimento, J. -D.; Castro, M.; da Costa, J. S.
Context. We present rotation period measurements for subgiants observed by CoRoT. Interpreting the modulation of stellar light that is caused by star-spots on the time scale of the rotational period depends on knowing the fundamental stellar parameters.
Aims: Constraints on the angular momentum distribution can be extracted from the true stel…
Decorrelation Times of Photospheric Fields and Flows
Welsch, B. T.; Kusano, K.; Yamamoto, T. T. +1 more
We use autocorrelation to investigate evolution in flow fields inferred by applying Fourier local correlation tracking (FLCT) to a sequence of high-resolution (0farcs3), high-cadence (sime 2 minute) line-of-sight magnetograms of NOAA active region (AR) 10930 recorded by the narrowband filter imager of the Solar Optical Telescope aboard the Hinode …
Multipoint study of magnetosheath magnetic field fluctuations and their relation to the foreshock
Němeček, Z.; Gutynska, O.; Šimůnek, J. +2 more
The magnetosheath is occupied with a variety of low-frequency fluctuations from different sources. Among them, the bow shock and dominantly foreshock processes are often considered as their major contributors. We use distant (Wind) and close (Geotail) interplanetary magnetic field monitors and compare their measurements with simultaneous magnetic …
X-ray spectroscopy of clusters of galaxies
Ota, Naomi
Clusters of galaxies are the most massive objects in the Universe and precise knowledge of their mass structure is important to understand the history of structure formation and constrain still unknown types of dark contents of the Universe. X-ray spectroscopy of galaxy clusters provides rich information about the physical state of hot intracluste…