5,674 research outputs found
Supernovae and Cosmology with Future European Facilities
Prospects for future supernova surveys are discussed, focusing on the ESA
Euclid mission and the European Extremely Large Telescope(E-ELT), both expected
to be in operation around the turn of the decade. Euclid is a 1.2m space survey
telescope that will operate at visible and near-infrared wavelengths, and has
the potential to find and obtain multi-band lightcurves for thousands of
distant supernovae. The E-ELT is a planned general-purpose ground-based
40m-class optical-IR telescope with adaptive optics built in, which will be
capable of obtaining spectra of Type Ia supernovae to redshifts of at least
four. The contribution to supernova cosmology with these facilities will be
discussed in the context of other future supernova programs such as those
proposed for DES, JWST, LSST and WFIRST.Comment: To appear in proceedings of the Royal Society scientific discussion
meeting "New windows on transients across the Universe", 23-24 April 201
Probable or Improbable Universe? Correlating Electroweak Vacuum Instability with the Scale of Inflation
Measurements of the Higgs boson and top quark masses indicate that the
Standard Model Higgs potential becomes unstable around
GeV. This instability is cosmologically relevant since quantum fluctuations
during inflation can easily destabilize the electroweak vacuum if the Hubble
parameter during inflation is larger than (as preferred by the
recent BICEP2 measurement). We perform a careful study of the evolution of the
Higgs field during inflation, obtaining different results from those currently
in the literature. We consider both tunneling via a Coleman-de Luccia or
Hawking-Moss instanton, valid when the scale of inflation is below the
instability scale, as well as a statistical treatment via the Fokker-Planck
equation appropriate in the opposite regime. We show that a better
understanding of the post-inflation evolution of the unstable AdS vacuum
regions is crucial for determining the eventual fate of the universe. If these
AdS regions devour all of space, a universe like ours is indeed extremely
unlikely without new physics to stabilize the Higgs potential; however, if
these regions crunch, our universe survives, but inflation must last a few
e-folds longer to compensate for the lost AdS regions. Lastly, we examine the
effects of generic Planck-suppressed corrections to the Higgs potential, which
can be sufficient to stabilize the electroweak vacuum during inflation.Comment: 26 pages, 7 figures. Clarifications added. Matches published version
in JHE
Automated optical identification of a large complete northern hemisphere sample of flat spectrum radio sources with S_6cm > 200 mJy
This paper describes the automated optical APM identification of radio
sources from the Jodrell Bank - VLA Astrometric Survey (JVAS), as used for the
search for distant radio-loud quasars. The sample has been used to investigate
possible relations between optical and radio properties of flat spectrum radio
sources. From the 915 sources in the sample, 756 have an optical APM
identification at a red (e) and/or blue (o) plate,resulting in an
identification fraction of 83% with a completeness and reliability of 98% and
99% respectively. About 20% are optically identified with extended APM objects
on the red plates, e.g. galaxies. However the distinction between galaxies and
quasars can not be done properly near the magnitude limit of the POSS-I plates.
The identification fraction appears to decrease from >90% for sources with a 5
GHz flux density of >1 Jy, to <80% for sources at 0.2 Jy. The identification
fraction, in particular that for unresolved quasars, is found to be lower for
sources with steeper radio spectra. In agreement with previous studies, we find
that the quasars at low radio flux density levels also tend to have fainter
optical magnitudes, although there is a large spread. In addition, objects with
a steep radio-to-optical spectral index are found to be mainly highly polarised
quasars, supporting the idea that in these objects the polarised synchrotron
component is more prominent. It is shown that the large spread in
radio-to-optical spectral index is possibly caused by source to source
variations in the Doppler boosting of the synchrotron component [Abridged].Comment: LaTex, 17 pages, 5 gif figures, 4 tables. Accepted for publication in
MNRAS. High resolution figures can be found at http://www.roe.ac.uk/~ignas
Statistics in League of Legends: Analyzing Runes for Last-Hitting
While other sports have statisticians to evaluate players and their stats, in electronic sports there is a need for statisticians to evaluate different parts of the game. League of Legends is the most popular of ESports and is the focus of this discussion. The mechanic of focus here is runes which give boosts to the players stats in-game like being able to do extra damage. We will be finding the effectiveness of these runes by looking at gold efficiency, help with last hitting, and extra damage dealt through the use of Python
Demand For International Reserves in ASEAN-5 Economies
The ASEAN-5 economies were observed to increase their demand for international reserves after the 1997 Asian financial crisis. This was coincided with their consistent current account surplus during the same period. Thus, this study attempts to investigate the existence of long-run relationship between reserve demand and current account for the period of 1997-2005. The Autoregressive Distributed Lag (ARDL) bounds test approach as proposed by Pesaran, Shin, and Smith (2001) was employed, and the empirical results revealed that current account surplus leads to the rise in the demand for international reserves in Indonesia, Malaysia, and Singapore.Bound Test, ARDL Approach, International Reserves, ASEAN-5
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