pinecone/core-2020-05-10-deduplication huggingface dataset:
Observational dynamics of low-mass stellar systems

The last fifteen years have seen the discovery of new types of low-mass
stellar systems that bridge the gap between the once well-separated regimes of
galaxies and of star clusters. Whether such objects are considered galaxies
depends also on the definition of the term "galaxy", and several possible
criteria are based on their internal dynamics (e.g. the common concept that
galaxies contain dark matter). Moreover, studying the internal dynamics of
low-mass stellar systems may also help understand their origin and evolutionary
history. The focus of this paper is on two classes of stellar systems at the
interface between star clusters and dwarf galaxies: ultra-compact dwarf
galaxies (UCDs) and diffuse Galactic globular clusters (GCs). A review of our
current knowledge on the properties of UCDs is provided and dynamical
considerations applying to diffuse GCs are introduced. In the following, recent
observational results on the internal dynamics of individual UCDs and diffuse
Galactic globular clusters are presented.Comment: 15 pages, 6 figures; Doctoral Thesis Award Lecture 2013, to appear in
  AN / Reviews in Modern Astronomy, Vol. 2
The highest energy neutrinos: first evidence for cosmic origin

Developments in neutrino astronomy have been to a great extent motivated by
the search for the sources of the cosmic rays, leading at a very early stage to
the concept of a cubic kilometer neutrino detector. Almost four decades later
such an instrument, IceCube, is taking data and has produced the first evidence
for a flux of high-energy neutrinos of cosmic origin. After a brief review of
the history of the field, we will introduce IceCube and describe the first
analysis of data taken with the completed instrument. The atmospheric neutrino
flux cannot accommodate an excess of 28 neutrinos observed with energies above
60 TeV. We will briefly speculate on the origin of these events. Readers
interested specifically in IceCube results may refer directly to section 3.Comment: 22 pages, 8 figures, Pontecorvo 201
Positive and negative feedback by AGN jets in high-redshift galaxies

Simulations of feedback by jets from active galactic nuclei (AGN) in the past
mostly focused on the interaction at large scales as the circumgalactic medium
or intra-cluster medium for clusters of galaxies. Only in recent years,
simulations have included the interaction of jets with a highly inhomogeneous
medium as required by a multi-phase interstellar medium (ISM). At the same
time, feedback by AGN has become a common component for cosmological
simulations of galaxy evolution to form massive galaxies compatible with
observations. I will present some of our recent results and will put them into
further context of other feedback simulations and how the opposing effects of
positive and negative feedback by jets might be understood in terms of
different properties of the ISM.Comment: 6 pages, 1 figure, published in final form in Reviews in Modern
  Astronomy, Vol. 26, AN 335, 531. Based on invited talk at annual meeting 2013
  of the Astronomische Gesellschaf
Jets from young stars and brown dwarfs

The protostellar outflow mechanism operates for a significant fraction of the
pre-main sequence phase of a solar mass star and is thought to have a key role
in star and perhaps even planet formation. This energetic mechanism manifests
itself in several different forms and on many scales. Thus outflow activity can
be probed in numerous different regimes from radio to X-ray wavelengths. Recent
discoveries have shown that it is not only solar mass stars that launch
outflows during their formation but also the sub-stellar brown dwarfs. In this
article what is currently known about jets from young stars is summarised,
including an outline of why it is important to study jets. The second part of
this article is dedicated to jets from young brown dwarfs. While only a small
number of brown dwarf outflows have been investigated to date, interesting
properties have been observed. Here observations of brown dwarf outflows are
described and what is currently known of their properties compared to low mass
protostellar outflows.Comment: Astronomische Nachrichten, Special Issue: Reviews in Modern
  Astrononm
Asiago Supernova classification program: blowing out the first two
  hundred candles

We present the compilation of the first 221 supernovae classified during the
Asiago Classification Program (ACP). The details of transients classification
and the preliminarily reduced spectra, in fits format, are immediately posted
on the Padova-Asiago SN group web site. The achieved performances for the first
2 years of the ACP are analysed, showing that half of all our classifications
were made within 5 days from transient detection. The distribution of the
supernova types of this sample resembles the distribution of the general list
of all the supernovae listed in the Asiago SN catalog (ASNC, Barbon et al.
1999). Finally, we use our sub-sample of 78 core-collapse supernovae, for which
we retrieve the host-galaxy morphology and r-band absolute magnitudes, to study
the observed subtype distribution in dwarf compared to giant galaxies. This
ongoing program will give its contribution to the classification of the large
number of transients that will be soon delivered by the Gaia mission.Comment: Accepted Astronomische Nachrichte
The Chinese comet observation in AD 773 January

The strong 14C increase in the year AD 774/5 detected in one German and two
Japanese trees was recently suggested to have been caused by an impact of a
comet onto Earth and a deposition of large amounts of 14C into the atmosphere
(Liu et al. 2014). The authors supported their claim using a report of a
historic Chinese observation of a comet ostensibly colliding with Earth's
atmosphere in AD 773 January. We show here that the Chinese text presented by
those authors is not an original historic text, but that it is comprised of
several different sources. Moreover, the translation presented in Liu et al. is
misleading and inaccurate. We give the exact Chinese wordings and our English
translations. According to the original sources, the Chinese observed a comet
in mid January 773, but they report neither a collision nor a large coma, just
a long tail. Also, there is no report in any of the source texts about "dust
rain in the daytime" as claimed by Liu et al. (2014), but simply a normal dust
storm. Ho (1962) reports sightings of this comet in China on AD 773 Jan 15
and/or 17 and in Japan on AD 773 Jan 20 (Ho 1962). At the relevant historic
time, the Chinese held that comets were produced within the Earth's atmosphere,
so that it would have been impossible for them to report a "collision" of a
comet with Earth's atmosphere. The translation and conclusions made by Liu et
al. (2014) are not supported by the historical record. Therefore, postulating a
sudden increase in 14C in corals off the Chinese coast precisely in mid January
773 (Liu et al. 2014) is not justified given just the 230Th dating for AD 783
\pm 14.Comment: 4 pages with one figure, paper in press in Astronomical Notes 201
A solar super-flare as cause for the 14C variation in AD 774/5 ?

We present further considerations regarding the strong 14C variation in AD
774/5. For its cause, either a solar super-flare or a short Gamma-Ray Burst
were suggested. We show that all kinds of stellar or neutron star flares would
be too weak for the observed energy input at Earth in AD 774/5. Even though
Maehara et al. (2012) present two super-flares with 10e35 erg of presumably
solar-type stars, we would like to caution: These two stars are poorly studied
and may well be close binaries, and/or having a M-type dwarf companion, and/or
may be much younger and/or much more magnetic than the Sun - in any such case,
they might not be true solar analog stars. From the frequency of large stellar
flares averaged over all stellar activity phases (maybe obtained only during
grand activity maxima), one can derive (a limit of) the probability for a large
solar flare at a random time of normal activity: We find the probability for
one flare within 3000 years to be possibly as low as 0.3 to 0.008 considering
the full 1 sigma error range. Given the energy estimate in Miyake et al. (2012)
for the AD 774/5 event, it would need to be \sim 2000 stronger than the
Carrington event as solar super-flare. If the AD 774/5 event as solar flare
would be beamed (to an angle of only 24 deg), 100 times lower energy would be
needed. A new AD 774/5 energy estimate by Usoskin et al. (2013) with a
different carbon cycle model, yielding 4 or 6 time lower 14C production,
predicts 4-6 times less energy. If both reductions are applied, the AD 774/5
event would need to be only 4 times stronger than the Carrington event in 1859
(if both had similar spectra). However, neither 14C nor 10Be peaks were found
around AD 1859. Hence ...Comment: 15 pages, 3 figures, paper in press in Astronomical Notes 201
TASTE IV. Refining ephemeris and orbital parameters for HAT-P-20b and
  WASP-1b

We present four new light curves of transiting exoplanets WASP-1b and
HAT-P-20b, observed within the TASTE (The Asiago Search for Transit timing
variations of Exoplanets) project. We re-analyzed light curves from the
literature in a homogeneous way, calculating a refined ephemeris and
orbital-physical parameters for both objects. WASP-1b does not show any
significant Transit Timing Variation signal at the 120 s-level. As for
HAT-P-20b, we detected a deviation from our re-estimated linear ephemeris that
could be ascribed to the presence of a perturber or, more probably, to a
previously unnoticed high level of stellar activity. The rotational period of
HAT-P-20 A we obtained from archival data (P_rot ~ 14.5 days), combined with
its optical variability and strong emission of CaII H&K lines, is consistent
with a young stellar age (< 1 Gyr) and support the hypothesis that stellar
activity may be responsible of the measured deviations of the transit times.Comment: 7 pages, 4 figures, 3 tables, accepted to Astronomische Nachrichte
Gravitational entropy of cosmic expansion

We apply a recent proposal to define "gravitational entropy" to the expansion
of cosmic voids within the framework of non-perturbative General Relativity. By
considering CDM void configurations compatible with basic observational
constraints, we show that this entropy grows from post-inflationary conditions
towards a final asymptotic value in a late time fully non-linear regime
described by the Lemaitre-Tolman-Bondi (LTB) dust models. A qualitatively
analogous behavior occurs if we assume a positive cosmological constant
consistent with a $\Lambda$-CDM background model. However, the $\Lambda$ term
introduces a significant suppression of entropy growth with the terminal
equilibrium value reached at a much faster rate.Comment: 5 Pages, 2 figures, AN style. Contribution to Proceedings of the
  Second Caribbean Symposium on Nuclear and Astroparticle Physics (STARS 2013),
  La Habana, Cuba, 5-9 May 201
Mini-review on mini-black holes from the mini-Big Bang

We review the basic ideas about man-made quantum mechanical black holes. We
start by an overview of the proposed attempts to circumvent the hierarchy
problem. We study the phenomenological implications of a strong gravity regime
at the terascale and we focus on the issue of microscopic black holes. We
provide the experimental bounds on relevant quantities as they emerge from
major ongoing experiments. The experimental results exclude the production of
black holes in collisions up to 8 TeV. We provide some possible explanations of
such negative results in view of forthcoming investigations.Comment: 7 pages, 5 figures, paper based on the talk given at
  STARS2013/SMFNS2013, Havana/Varadero, Cuba, 4-10 May 2013, submitted for a
  special issue of Astronomische Nachrichten; v2 additional references and
  comment
Parton-hadron dynamics in heavy-ion collisions

The dynamics of partons and hadrons in relativistic nucleus-nucleus
collisions is analyzed within the novel Parton-Hadron-String Dynamics (PHSD)
transport approach, which is based on a dynamical quasiparticle model for the
partonic phase (DQPM) including a dynamical hadronization scheme. The PHSD
approach is applied to nucleus-nucleus collisions from low SPS to LHC energies.
The traces of partonic interactions are found in particular in the elliptic
flow of hadrons and in their transverse mass spectra. We investigate also the
equilibrium properties of strongly-interacting infinite parton-hadron matter
characterized by transport coefficients such as shear and bulk viscosities and
the electric conductivity in comparison to lattice QCD results.Comment: 6 pages, 7 figures, Proceedings of the STARS2013 and SMFNS2013
  conferences, 4-10 May 2013, Havana/Varadero, Cub
Modelling the Magnetic Field Configuration of Neutron Stars

The properties of the extremely strong magnetic fields of neutron stars
affect in a unique way their evolution and the associated phenomenology. Due to
the lack of constraints from direct observations, our understanding of the
magnetic field configuration in neutron star interiors depends on the progress
in theoretical modelling. Here we discuss the effort in building models of
magnetized neutron stars focussing on some of the recent results. In
particular, we comment on the instability of purely poloidal and purely
toroidal magnetic field configurations and on the evidence in favour of the
so-called twisted-torus solutions. We conclude with an outlook on the present
status of the field and future directions.Comment: 6 pages, 2 figures. Proceedings of STARS2013 - 2nd Caribbean
  Symposium on Cosmology, Gravitation, Nuclear and Astroparticle Physics /
  SMFNS2013 - 3rd International Symposium on Strong Electromagnetic Fields and
  Neutron Star
On the possibility of a 130 GeV gamma-ray line from annihilating singlet
  fermionic dark matter

There is evidence for a spectral line at $E_\gamma\approx 130$ GeV in the
Fermi-LAT data that can be explained as dark mater particles annihilating into
photons. We review a well known dark matter model that consists in a singlet
Dirac fermion and a singlet scalar. The scalar implements spontaneous symmetry
breaking in the dark sector, and is responsible for the communication between
dark matter and Standard Model particles through a coupling to the Higgs. These
interactions are supressed by the mixing between the scalar and the Higgs.
Therefore, the singlet fermionic dark matter is naturally a weakly interacting
massive particle (WIMP) and can explain the observed relic density. We show
that this model cannot produce the signal identified in the Fermi-LAT data.
Thus, we propose a modification in the model by introducing a new scalar
multiplet that carries electric charge and couples to the singlet scalar. It
enhances the annihilation into two photons and succeeds in producing the
observed signal. We also discuss the resulting increase of the branching ratio
of the $h\rightarrow\gamma\gamma$ process, which is consistent with
measurements from the CMS experiments
Effects of strong magnetic fields on the population of hyperon stars

In this contribution we study the effects of strong magnetic fields on the
particle population of neutron stars with hyperon degrees of freedom in their
composition. The star matter is described by a multi-component model with
parameterized baryon-meson interaction couplings. We study the magnetic effects
on the equation of state (EoS) due to the Landau quantization, assuming a
density dependent static magnetic field that reaches about $10^{19}\,G$ in the
center of the star. The Tolman-Oppenheimer-Volkoff equations are solved in
order to understand the dependence of the mass-radius relation and hyperon
population on the magnetic field intensity assuming different interaction
coupling schemes.Comment: Prepared for conference STARS2013 - 2nd Caibbean Symposium on
  Cosmology, Gravitaion, Nuclear and Astroparticle Physics / SMFNS2013 - 3rd
  International Symposium on Strong Electromagnetic Fields and Neutron Star
CP Violation in Dual Dark Matter

In this paper we study the consequences of extending dual symmetry (DuSy) to
include a generic $C_\mu$ vector field as a dual partner of the photon $A_\mu$.
A new combined field, the complex $Z^\prime_\mu$, is obtained from $C_\mu$ and
$A_\mu$. The promotion of dual symmetry to a local symmetry for $Z^\prime_\mu$
implies in the inclusion of an extra complex vector field $W_\mu$ with a
complex gauge transformation. A dual dark matter (DM) Lagrangian ${\cal L}_{\rm
DDM}$ is obtained from the general DuSy invariant Lagrangian ${\cal L}_{\rm
DuSy}$. Our tentative conjecture is to interpret $W_\mu$ as the actual weak
interaction charged gauge boson $W^{\pm}_\mu$, which leads us to speculate
about a possible extra CP violation scenarios for future calculations
Effects of AMM on the EoS of Magnetized Dense Systems

We investigate the effects of the anomalous magnetic moment (AMM) in the EoS
of a fermion system in the presence of a magnetic field. In the region of
strong magnetic fields ($B>m^2$) the AMM is found from the one-loop fermion
self-energy. In contrast to the weak-field AMM found by Schwinger, in the
strong magnetic field case, the AMM depends on the Landau level (LL) and
decreases with it. The effects of the AMM in the EoS at intermediate-to-large
fields can be found introducing the one-loop, LL-dependent AMM in the effective
Lagrangian that is then used to find the thermodynamic potential of the system.
We compare the plots of the parallel and perpendicular pressures versus the
magnetic field in the strong field region considering the LL-dependent AMM, the
Schwinger AMM, and no AMM at all. The results clearly show a separation between
the physical magnitudes found using the Schwinger AMM and the LL-dependent AMM.
This is an indication of the inconsistency of considering the Schwinger AMM
beyond the weak field region $B< m^2$ where it was originally found. The curves
for the EoS, pressures and magnetization at different fields give rise to the
well-known de Haas van Alphen oscillations, associated to the change in the
number of LL contributing at different fields.Comment: Contribution for the Conference Proceedings of the STARS2013- 2nd
  Caribbean Symposium on Cosmology, Gravitation, Nuclear and Astroparticle
  Physics/SMFNS- 3rd International Symposium on Strong Electromagnetic Fields
  and Neutron. 4-10 May 2013 Havana/Varadero - CUB
Effective Field Theory for Neutron Stars with Genuine Many-body Forces

The aim of our contribution is to shed some light on open questions facing
the high density nuclear many-body problem. We focus our attention on the
conceptual issue of naturalness and its role for the baryon-meson coupling for
nuclear matter at high densities. As a guideline for the strengths of the
various couplings the concept of naturalness has been adopted. In order to
encourage possible new directions of research, we discuss relevant aspects of a
relativistic effective theory for nuclear matter with natural parametric
couplings and genuine many-body forces. Among other topics, we discuss in this
work the connection of this theory with other known effective Quantum
Hadrodynamics (QHD) models found in literature and how we can potentially use
our approach to describe new physics for neutron stars. We also show some
preliminary results for the equation of state, population profiles and
mass-radius relation for neutron stars assuming local charge neutrality and
beta equilibrium.Comment: Prepared for conference STARS2013 - 2nd Caibbean Symposium on
  Cosmology, Gravitaion, Nuclear and Astroparticle Physics / SMFNS2013 - 3rd
  International Symposium on Strong Electromagnetic Fields and Neutron Star
Rotational Behaviors and Magnetic Field Evolution of Radio Pulsars

The observed long-term spin-down evolution of isolated radio pulsars cannot
be explained by the standard magnetic dipole radiation with a constant braking
torque. However how and why the torque varies still remains controversial,
which is an outstanding problem in our understanding of neutron stars. We have
constructed a phenomenological model of the evolution of surface magnetic
fields of pulsars, which contains a long-term decay modulated by short-term
oscillations; a pulsar's spin is thus modified by its magnetic field evolution.
The predictions of this model agree with the precisely measured spin evolutions
of several individual pulsars; the derived parameters suggest that the Hall
drift and Hall waves in the NS crusts are probably responsible for the
long-term change and short-term quasi-periodical oscillations, respectively.
Many statistical properties of the timing noise of pulsars can be well
re-produced with this model, including correlations and the distributions of
the observed braking indices of the pulsars, which span over a range of more
than 100 millions. We have also presented a phenomenological model for the
recovery processes of classical and slow glitches, which can successfully model
the observed slow and classical glitch events without biases.Comment: 6 pages, 9 figures, submitted to conference proceedings of SMFNS2013
  (Strong electromagnetic field and neutron stars 2013
Multiperiodic semiregular variable stars in the ASAS data base: A pilot
  study

Based on a search for multi-periodic variability among the semi-regular red
variable stars in the database of the All Sky Automated Survey (ASAS), a sample
of 72 typical examples is presented. Their period analysis was performed using
Discrete Fourier Transform. In 41 stars we identified two significant periods
each, simultaneously present, while the remaining 31 cases revealed even three
such periods per star. They occur in a range roughly between 50 and 3000 days.
Inter-relationships between these periods were analyzed using the "double
period diagram" which compares adjacent periods, and the so-called "Petersen
diagram", the period ratio vs. the shorter period. In both diagrams we could
identify six sequences of accumulation of the period values. For five of these
sequences (containing 97% of all data points) we found an almost perfect
coincidence with those of previous studies which were based on very different
samples of semi-regular red variables. Therefore, existence and locations of
these sequences in the diagrams seem to be universal features, which appear in
any data set of semi-regularly variable red giants of the AGB; we conclude that
they are caused by different pulsation modes as the typical and consistent
properties of similar stellar AGB configurations. Stellar pulsations can be
considered as the principal cause of the observed periodic variability of these
stars, and not binary, rotation of a spotted surface or other possible reasons
suggested in the literature.Comment: 6 pages, 6 figures and 3 tables. Accepted to AN, july 201