894 research outputs found
Symplectic structure and monopole strength in 12C
The relation between the monopole transition strength and existence of
cluster structure in the excited states is discussed based on an algebraic
cluster model. The structure of C is studied with a 3 model, and
the wave function for the relative motions between clusters are
described by the symplectic algebra , which corresponds to the
linear combinations of states with different multiplicities.
Introducing algebra works well for reducing the number of the basis
states, and it is also shown that states connected by the strong monopole
transition are classified by a quantum number of the
algebra.Comment: Phys. Rev. C in pres
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Multimedia broadcast and internet satellite system design and user trial results
The EU funded project, System for Advanced Multimedia Broadcast
and IT Services (SAMBITS), has created an enhanced and synchronised,
multimedia terminal for merging satellite broadcast and internet
telecommunication services in a way that efficiently combines the large
bandwidth of the broadcast channel and the interactivity of the internet.
This paper proposes a novel broadcast and internet service concept, illustrates
this concept with two service scenarios and develops a system architecture to
demonstrate the range of key benefits provided by these new technologies.
It then describes the interactive multimedia terminal that was used for
consuming this new service concept. Finally, the results of the user trials on the
terminal are presented and discussed
Application of the generalized two-center cluster model to 10Be
A generalized two-center cluster model (GTCM), including various partitions
of the valence nucleons around two alpha-cores, is proposed for studies on the
exotic cluster structures of Be isotopes. This model is applied to the 10Be =
alpha + alpha + n + n system and the adiabatic energy surfaces for alpha-alpha
distances are calculated. It is found that this model naturally describes the
formation of the molecular orbitals as well as that of asymptotic cluster
states dependeing on their relative distance. In the negative-parity state, a
new type of the alpha + 6He cluster structure is also predicted.Comment: 5 pages, 3 figure
A remarkable recurrent nova in M 31: The 2010 eruption recovered and evidence of a six-month period
The Andromeda Galaxy recurrent nova M31N 2008-12a has been caught in eruption
nine times. Six observed eruptions in the seven years from 2008 to 2014
suggested a duty cycle of ~1 year, which makes this the most rapidly recurring
system known and the leading single-degenerate Type Ia Supernova progenitor
candidate; but no 2010 eruption has been found so far. Here we present evidence
supporting the recovery of the 2010 eruption, based on archival images taken at
and around the time. We detect the 2010 eruption in a pair of images at 2010
Nov 20.52 UT, with a magnitude of m_R = 17.84 +/- 0.19. The sequence of seven
eruptions shows significant indications of a duty cycle slightly shorter than
one year, which makes successive eruptions occur progressively earlier in the
year. We compared three archival X-ray detections with the well observed
multi-wavelength light curve of the 2014 eruption to accurately constrain the
time of their optical peaks. The results imply that M31N 2008-12a might have in
fact a recurrence period of ~6 months (175 +/- 11 days), making it even more
exceptional. If this is the case, then we predict that soon two eruptions per
year will be observable. Furthermore, we predict the next eruption will occur
around late Sep 2015. We encourage additional observations.Comment: 4 pages, 3 figures, 2 tables; submitted to A&A Letter
A massive star origin for an unusual helium-rich supernova in an elliptical galaxy
The unusual helium-rich (type Ib) supernova SN 2005E is distinguished from
any supernova hitherto observed by its faint and rapidly fading light curve,
prominent calcium lines in late-phase spectra and lack of any mark of recent
star formation near the supernova location. These properties are claimed to be
explained by a helium detonation in a thin surface layer of an accreting white
dwarf (Perets et al. 2010). Here we report on observations of SN 2005cz
appeared in an elliptical galaxy, whose observed properties resemble those of
SN 2005E in that it is helium-rich and unusually faint, fades rapidly, shows
much weaker oxygen emission lines than those of calcium in the well-evolved
spectrum. We argue that these properties are best explained by a core-collapse
supernova at the low-mass end () of the range of massive stars
that explode (Smartt 2009). Such a low mass progenitor had lost its
hydrogen-rich envelope through binary interaction, having very thin oxygen-rich
and silicon-rich layers above the collapsing core, thus ejecting a very small
amount of radioactive Ni and oxygen. Although the host galaxy NGC 4589
is an elliptical, some studies have revealed evidence of recent star-formation
activity (Zhang et al. 2008), consistent with the core-collapse scenario.Comment: Accepted by Nature (24 March 2010), 32 pages including Supplementary
Informatio
Rapid prototyping and fast user trial of multimedia broadcast and cellular services
This paper presents the results of fast user trial of multimedia services that are enabled when a mobile terminal has access to converged services over digital broadcast and mobile telecommunications networks. It first describes the motivations behind developing this system and describes the service scenarios that benefit most from it. It then provides an overview of the service components of the test case scenario. Finally, it presents the results of fast user trials on end users of the services that were developed. This work was conducted as part of the EU-funded CISMUNDUS project
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