440 research outputs found
Hybrid star structure with the Field Correlator Method
We explore the relevance of the color-flavor locking phase in the equation of
state (EoS) built with the Field Correlator Method (FCM) for the description of
the quark matter core of hybrid stars. For the hadronic phase, we use the
microscopic Brueckner-Hartree-Fock (BHF) many-body theory, and its relativistic
counterpart, i.e. the Dirac-Brueckner (DBHF). We find that the main features of
the phase transition are directly related to the values of the quark-antiquark
potential , the gluon condensate and the color-flavor
superconducting gap . We confirm that the mapping between the FCM and
the CSS (constant speed of sound) parameterization holds true even in the case
of paired quark matter. The inclusion of hyperons in the hadronic phase and its
effect on the mass-radius relation of hybrid stars is also investigated.Comment: 15 pages, 8 figures ; revised version to be published in the EPJA
Topical Issue on "Exotic Matter in Neutron Stars
The Emergence of the ‘Social Economy’: the Australian not-for-profit sector in transition
The Not-for-Profit (NFP) sector in Australia is currently in transition. There is a
growing recognition, in Australia and worldwide, that government and philanthropic
funds are insufficient to address the problems facing society; as well as demands for increased accountability and demonstration of improved outcomes from traditional funding to the non-profit sector. There is also a growing global interest in social
enterprises, socially responsible investment, and, in particular, impact investing –
where investors aim to achieve a blend between commercial value and social impact. These trends are contributing to the emergence of new organizational forms, partnerships and financial products, and as a consequence, NFP organizations are becoming just one form of organization within the broader spectrum of organizations and activity described as the ‘social economy’. This research project begins to explore this transition by analysing a sample of organizations in Australia that while having formal non-profit structures, identified themselves as social enterprises in a bid for funding from one of Australia’s leading corporate foundations, the Westpac Foundation. The research builds on previous studies, yet also enables more detailed data on the leadership, governance, human resources, financial challenges, and focus of activities of social enterprises and raises questions about the future of the sector and the social economy
Detection of Contact Binaries Using Sparse High Phase Angle Lightcurves
We show that candidate contact binary asteroids can be efficiently identified
from sparsely sampled photometry taken at phase angles >60deg. At high phase
angle, close/contact binary systems produce distinctive lightcurves that spend
most of the time at maximum or minimum (typically >1mag apart) brightness with
relatively fast transitions between the two. This means that a few (~5) sparse
observations will suffice to measure the large range of variation and identify
candidate contact binary systems. This finding can be used in the context of
all-sky surveys to constrain the fraction of contact binary near-Earth objects.
High phase angle lightcurve data can also reveal the absolute sense of the
spin.Comment: 4 pages, 4 figures, 1 table. Accepted for publication in ApJ
SiPM and front-end electronics development for Cherenkov light detection
The Italian Institute of Nuclear Physics (INFN) is involved in the
development of a demonstrator for a SiPM-based camera for the Cherenkov
Telescope Array (CTA) experiment, with a pixel size of 66 mm. The
camera houses about two thousands electronics channels and is both light and
compact. In this framework, a R&D program for the development of SiPMs suitable
for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different
photosensors have been produced at Fondazione Bruno Kessler (FBK), with
different micro-cell dimensions and fill factors, in different geometrical
arrangements. At the same time, INFN is developing front-end electronics based
on the waveform sampling technique optimized for the new NUV SiPM. Measurements
on 11 mm, 33 mm, and 66 mm NUV SiPMs
coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Extreme Kuiper Belt Object 2001 QG298 and the Fraction of Contact Binaries
Extensive time-resolved observations of Kuiper Belt object 2001 QG298 show a
lightcurve with a peak-to-peak variation of 1.14 +-0.04 magnitudes and
single-peaked period of 6.8872 +- 0.0002 hr. The mean absolute magnitude is
6.85 magnitudes which corresponds to a mean effective radius of 122 (77) km if
an albedo of 0.04 (0.10) is assumed. This is the first known Kuiper Belt object
and only the third minor planet with a radius > 25 km to display a lightcurve
with a range in excess of 1 magnitude. We find the colors to be typical for a
Kuiper Belt object (B-V = 1.00 +- 0.04, V-R = 0.60 +- 0.02) with no variation
in color between minimum and maximum light. The large light variation,
relatively long double-peaked period and absence of rotational color change
argue against explanations due to albedo markings or elongation due to high
angular momentum. Instead, we suggest that 2001 QG298 may be a very close or
contact binary similar in structure to what has been independently proposed for
the Trojan asteroid 624 Hektor. If so, its rotational period would be twice the
lightcurve period or 13.7744 +- 0.0004 hr. By correcting for the effects of
projection, we estimate that the fraction of similar objects in the Kuiper Belt
is at least 10% to 20% with the true fraction probably much higher. A high
abundance of close and contact binaries is expected in some scenarios for the
evolution of binary Kuiper Belt objects.Comment: 15 text pages,6 figures(Color),5 Tables, Accepted to AJ for May 200
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