1,839 research outputs found
Cosmological constraints from the convergence 1-point probability distribution
We examine the cosmological information available from the 1-point
probability distribution (PDF) of the weak-lensing convergence field, utilizing
fast L-PICOLA simulations and a Fisher analysis. We find competitive
constraints in the - plane from the convergence PDF with
pixels compared to the cosmic shear power spectrum with an
equivalent number of modes (). The convergence PDF also partially
breaks the degeneracy cosmic shear exhibits in that parameter space. A joint
analysis of the convergence PDF and shear 2-point function also reduces the
impact of shape measurement systematics, to which the PDF is less susceptible,
and improves the total figure of merit by a factor of , depending on the
level of systematics. Finally, we present a correction factor necessary for
calculating the unbiased Fisher information from finite differences using a
limited number of cosmological simulations.Comment: 10 pages, 5 figure
Isobaric multiplet mass equation in the quartets
The observed mass excesses of analog nuclear states with the same mass number
and isospin can be used to test the isobaric multiplet mass equation
(IMME), which has, in most cases, been validated to a high degree of precision.
A recent measurement [Kankainen et al., Phys. Rev. C 93 041304(R) (2016)] of
the ground-state mass of Cl led to a substantial breakdown of the IMME
for the lowest quartet. The second-lowest
quartet is not complete, due to uncertainties associated with the identity of
the S member state. Using a fast Cl beam implanted into a plastic
scintillator and a high-purity Ge -ray detection array, rays
from the ClS sequence were measured. Shell-model
calculations using USDB and the recently-developed USDE interactions were
performed for comparison. Isospin mixing between the S isobaric analog
state (IAS) at 6279.0(6) keV and a nearby state at 6390.2(7) keV was observed.
The second state in S was observed at keV.
Isospin mixing in S does not by itself explain the IMME breakdown in the
lowest quartet, but it likely points to similar isospin mixing in the mirror
nucleus P, which would result in a perturbation of the P IAS
energy. USDB and USDE calculations both predict candidate P states
responsible for the mixing in the energy region slightly above
keV. The second quartet has been completed thanks to the identification of the
second S state, and the IMME is validated in this quartet
Heavy Quarkonium Potential Model and the State of Charmonium
A theoretical explanation of the observed splittings among the P~states of
charmonium is given with the use of a nonsingular potential model for heavy
quarkonia. We also show that the recently observed mass difference between the
center of gravity of the states and the state of
does not provide a direct test of the color hyperfine interaction in heavy
quarkonia. Our theoretical value for the mass of the state is in
agreement with the experimental result, and its E1 transition width is
341.8~keV. The mass of the state is predicted to be 3622.3~MeV.Comment: 15 page REVTEX documen
Brown dwarf census with the Dark Energy Survey year 3 data and the thin disc scale height of early L types
27 pages, 18 figuresIn this paper we present a catalogue of 11 745 brown dwarfs with spectral types ranging from L0 to T9, photometrically classified using data from the Dark Energy Survey (DES) year 3 release matched to the Vista Hemisphere Survey (VHS) DR3 and Wide-field Infrared Survey Explorer (WISE) data, covering ≈2400 deg2 up to iAB = 22. The classification method follows the same phototype method previously applied to SDSS-UKIDSS-WISE data. The most significant difference comes from the use of DES data instead of SDSS, which allow us to classify almost an order of magnitude more brown dwarfs than any previous search and reaching distances beyond 400 pc for the earliest types. Next, we also present and validate the GalmodBD simulation, which produces brown dwarf number counts as a function of structural parameters with realistic photometric properties of a given survey. We use this simulation to estimate the completeness and purity of our photometric LT catalogue down to iAB = 22, as well as to compare to the observed number of LT types. We put constraints on the thin disc scale height for the early L (L0–L3) population to be around 450 pc, in agreement with previous findings. For completeness, we also publish in a separate table a catalogue of 20 863 M dwarfs that passed our colour cut with spectral types greater than M6. Both the LT and the late M catalogues are found at DES release page https://des.ncsa.illinois.edu/releases/other/y3-mlt.Peer reviewedFinal Published versio
Review of Animal Rights Without Liberation: Applied Ethics and Human Obligations
This submission is a book review for Alasdair Cochrane\u27s Animal Rights Without Liberation: Applied Ethics and Human Obligation
Chemical Abundance Analysis of Tucana III, the Second -process Enhanced Ultra-Faint Dwarf Galaxy
We present a chemical abundance analysis of four additional confirmed member
stars of Tucana III, a Milky Way satellite galaxy candidate in the process of
being tidally disrupted as it is accreted by the Galaxy. Two of these stars are
centrally located in the core of the galaxy while the other two stars are
located in the eastern and western tidal tails. The four stars have chemical
abundance patterns consistent with the one previously studied star in Tucana
III: they are moderately enhanced in -process elements, i.e. they have
0.4 dex. The non-neutron-capture elements generally
follow trends seen in other dwarf galaxies, including a metallicity range of
0.44 dex and the expected trend in -elements, i.e., the lower
metallicity stars have higher Ca and Ti abundance. Overall, the chemical
abundance patterns of these stars suggest that Tucana III was an ultra-faint
dwarf galaxy, and not a globular cluster, before being tidally disturbed. As is
the case for the one other galaxy dominated by -process enhanced stars,
Reticulum II, Tucana III's stellar chemical abundances are consistent with
pollution from ejecta produced by a binary neutron star merger, although a
different -process element or dilution gas mass is required to explain the
abundances in these two galaxies if a neutron star merger is the sole source of
-process enhancement.Comment: 18 pages, 10 figures; accepted by Ap
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