Search Publications
Radial alignment of elliptical galaxies by the tidal force of a cluster of galaxies
Rong, Yu; Zhang, Shuang-Nan; Yi, Shu-Xu +1 more
Unlike the random radial orientation distribution of field elliptical galaxies, galaxies in a cluster are expected to point preferentially towards the centre of the cluster, as a result of the cluster's tidal force on its member galaxies. In this work, an analytic model is formulated to simulate this effect. The deformation time-scale of a galaxy …
HST Images Flash Ionization of Old Ejecta by the 2011 Eruption of Recurrent Nova T Pyxidis
Williams, Robert E.; Bond, Howard E.; Schaefer, Bradley E. +8 more
T Pyxidis is the only recurrent nova known to be surrounded by knots of material ejected in previous outbursts. Following the eruption that began on 2011 April 14.29, we obtained seven epochs (from 4 to 383 days after eruption) of Hubble Space Telescope narrowband Hα images of T Pyx. The ionizing flash of radiation from the nova event had no disce…
Near-Earth Cosmic Ray Decreases Associated with Remote Coronal Mass Ejections
Owens, M. J.; Lockwood, M.; Thomas, S. R. +2 more
Galactic cosmic ray (GCR) flux is modulated by both particle drift patterns and solar wind structures on a range of timescales. Over solar cycles, GCR flux varies as a function of the total open solar magnetic flux and the latitudinal extent of the heliospheric current sheet. Over hours, drops of a few percent in near-Earth GCR flux (Forbush decre…
Tracking the Geysers of Enceladus into Saturn’s E Ring
Porco, C. C.; Mitchell, C. J.; Weiss, J. W.
We examine Cassini Imaging Science Subsystem images of the E ring taken over a period of almost 7 yr, from 2006 September to 2013 July, in which long, sinuous structures dubbed tendrils are present. We model these structures by numerically integrating the trajectories of particles launched from the sources of the most active geysers recently locat…
Discovery of very high energy γ-ray emission from the blazar 1ES 0033+595 by the MAGIC telescopes
Maraschi, L.; Covino, S.; Antonelli, L. A. +159 more
The number of known very high energy (VHE) blazars is ∼50, which is very small in comparison to the number of blazars detected in other frequencies. This situation is a handicap for population studies of blazars, which emit about half of their luminosity in the γ-ray domain. Moreover, VHE blazars, if distant, allow for the study of the environment…
Detection of a Light Echo from the Otherwise Normal SN 2007af
Garnavich, P. M.; Riess, A. G.; Milne, P. A. +5 more
We present the discovery of a light echo from SN 2007af, a normal Type Ia supernova (SN Ia) in NGC 5584. Hubble Space Telescope images taken three years post explosion reveal two separate echoes: an outer echo and an extended central region, which we propose to be an inner echo for which details are unresolved. Multiple images were obtained in the…
Transients in finite inflation
Scacco, Andrew; Albrecht, Andreas
We test a model of inflation with a fast-rolling kinetic-dominated initial condition against data from Planck using Markov chain Monte Carlo parameter estimation. We test both an m2ϕ2 potential and the R +R2 gravity model and perform a full numerical calculation of both the scalar and tensor primordial power spectr…
Sustained lobe reconnection in Saturn's magnetotail
Thomsen, M. F.; Jackman, C. M.; Kurth, W. S. +3 more
The degree to which solar wind driving may affect Saturn's magnetosphere is not yet fully understood. We present observations that suggest that under some conditions the solar wind does govern the character of the plasma sheet in Saturn's outer magnetosphere. On 16 September 2006, the Cassini spacecraft, at a radial distance of 37 Rs ne…
Chandra and Xmm-Newton Observations of the Bimodal Planck SZ-Detected Cluster Plckg345.40-39.34 (A3716) with High and Low Entropy Subcluster Cores
Andrade-Santos, Felipe; Dawson, William A.; Jones, Christine +11 more
We present results from Chandra, XMM-Newton, and ROSAT observations of the Planck SZ-detected cluster A3716 (PLCKG345.40-39.34-G345). We show that G345 is, in fact, two subclusters separated on the sky by 400 kpc. We measure the subclusters’ gas temperatures (∼2-3 keV), total (∼1-2 × 1014 {{M}⊙ }) and gas (∼1-2 × 1013
High-velocity gas toward the LMC resides in the Milky Way halo
Rauch, T.; Werner, K.; de Boer, K. S. +1 more
Aims: To explore the origin of high-velocity gas in the direction of the Large Magellanic Cloud, (LMC) we analyze absorption lines in the ultraviolet spectrum of a Galactic halo star that is located in front of the LMC at d = 9.2+4.1-7.2 kpc distance.
Methods: We study the velocity-component structure of low and int…