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Herschel Observations of the W3 GMC (II): Clues to the Formation of Clusters of High-mass Stars
Martin, P. G.; Hill, T.; White, G. J. +18 more
The W3 giant molecular cloud is a prime target for investigating the formation of high-mass stars and clusters. This second study of W3 within the HOBYS Key Program provides a comparative analysis of subfields within W3 to further constrain the processes leading to the observed structures and stellar population. Probability density functions (PDFs…
Broad-band spectroscopy of the eclipsing high-mass X-ray binary 4U 1700-37 with Suzaku
Naik, Sachindra; Jaisawal, Gaurava K.
We present the results obtained from broad-band spectroscopy of the high-mass X-ray binary 4U 1700-37 using data from a Suzaku observation in 2006 September 13-14 covering 0.29-0.72 orbital phase range. The light curves showed significant and rapid variation in source flux during entire observation. We did not find any signature of pulsations in t…
Practical cosmology with lenses
Eales, S. A.
Surveys with submillimetre telescopes are revealing large numbers of gravitationally lensed high-redshift sources. I describe how, in practice, these lensed systems could be simultaneously used to estimate the values of cosmological parameters, test models for the evolution of the distribution of dark-matter haloes and investigate the properties o…
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…