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Saturn's F ring as seen by Cassini UVIS: Kinematics and statistics
Colwell, Joshua E.; Esposito, Larry W.; Sremčević, Miodrag +1 more
We present a new orbital model of Saturn's F ring core based on 93 occultations by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and the Voyager radio and stellar occultations. We demonstrate that the core, despite its intrinsic variability, is well-described as an inclined, freely precessing ellipse. We find that post-fit residuals with a r…
Data and two-dimensional scaling relations for galaxies in Abell 1689: a hint of size evolution at z∼ 0.2
Davies, Roger L.; Dalla Bontà, E.; Houghton, R. C. W. +1 more
We present imaging and spectroscopy of Abell 1689 (z= 0.183) from the Gemini multi-object spectrograph (GMOS) on the Gemini North telescope and the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). We measure integrated photometry from the GMOS g' and r' images (for 531 galaxies) and surface photometry from the HSTF625W image …
The cosmic history of hot gas cooling and radio active galactic nucleus activity in massive early-type galaxies
Lehmer, B. D.; Alexander, D. M.; Brandt, W. N. +5 more
We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z≈ 0.0-1.2 in the Chandra Deep Fields (CDFs). To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG su…
Illumination conditions at the Asteroid 4 Vesta: Implications for the presence of water ice
Stubbs, Timothy J.; Wang, Yongli
The mean illumination conditions and surface temperatures over one orbital period are calculated for the Asteroid 4 Vesta using a coarse digital elevation model produced from Hubble Space Telescope images. Even with the anticipated effects of finer-scale topography taken into account, it is unlikely that any significant permanently shadowed region…
The pulse profile and spin evolution of the accreting pulsar in Terzan 5, IGR J17480-2446, during its 2010 outburst
Stella, L.; Tramacere, A.; Ferrigno, C. +9 more
We analyse the spectral and pulse properties of the 11 Hz transient accreting pulsar, IGR J17480-2446, in the globular cluster Terzan 5, considering all the available Rossi X-Ray Timing Explorer, Swift and INTEGRAL observations performed during the outburst shown between 2010 October and November.
By measuring the pulse phase evolution we con…Classification of F ring features observed in Cassini UVIS occultations
Esposito, Larry W.; Sremčević, Miodrag; Meinke, Bonnie K. +1 more
The Cassini Ultraviolet Imaging Spectrograph (UVIS) has detected 27 statistically significant features in 101 occultations by Saturn’s F ring since July 2004. This work nearly doubles the number of features reported by Esposito et al. (Esposito, L.W. et al. [2008]. Icarus 194, 278-289). As the number of statistically significant features has grown…
Pickup protons: Comparisons using the three-dimensional MHD HHMS-PI model and Ulysses SWICS measurements
Sun, Wei; Intriligator, Devrie S.; Detman, Thomas +5 more
We report the first comparisons of pickup proton simulation results with in situ measurements of pickup protons obtained by the SWICS instrument on Ulysses. Simulations were run using the three dimensional (3D) time-dependent Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI). HHMS-PI is an MHD solar wind model, expanded to include …
A Spitzer Space Telescope survey of massive young stellar objects in the G333.2-0.4 giant molecular cloud
Lo, Nadia; Burton, Michael G.; Cunningham, Maria R. +3 more
The G333 giant molecular cloud contains a few star clusters and H II regions, plus a number of condensations currently forming stars. We have mapped 13 of these sources with the appearance of young stellar objects (YSOs) with the Spitzer Infrared Spectrograph in the Short-Low, Short-High and Long-High modules (5-36 µm). We use these spectra …
Detection of Accretion X-Rays from QS Vir: Cataclysmic or a Lot of Hot Air?
Drake, Jeremy J.; Steeghs, Danny; Kashyap, Vinay +1 more
An XMM-Newton observation of the nearby "pre-cataclysmic" short-period (P orb = 3.62 hr) binary QS Vir (EC 13471-1258) revealed regular narrow X-ray eclipses when the white dwarf passed behind its M2-4 dwarf companion. The X-ray emission provides a clear signature of mass transfer and accretion onto the white dwarf. The low-resolution X…
Soft Coronal X-Rays from β Pictoris
Schmitt, J. H. M. M.; Robrade, J.; Günther, H. M. +3 more
A-type stars are expected to be X-ray dark, yet weak emission has been detected from several objects in this class. We present new Chandra/HRC-I observations of the A5 V star β Pictoris. It is clearly detected with a flux of (9 ± 2) × 10-4 counts s-1. In comparison with previous data this constrains the emission mechanism and…