327 research outputs found
History Memorized and Recalled upon Glass Transition
The memory effect upon glassification is studied in the glass to rubber
transition of vulcanized rubber with the strain as a controlling parameter. A
phenomenological model is proposed taking the history of the temperature and
the strain into account, by which the experimental results are interpreted. The
data and the model demonstrate that the glassy state memorizes the time-course
of strain upon glassification, not as a single parameter but as the history
itself. The data also show that the effect of irreversible deformation in the
glassy state is beyond the scope of the present model.
Authors' remark: The title of the paper in the accepted version is above. The
title appeared in PRL is the one changed by a Senior Assistant Editor after
acceptance of the paper. The recovery of the title was rejected in the
correction process.Comment: 4 pages, 4 figure
B595: An Illustrated Review of Apple Virus Diseases
The writers have attempted to review the available literature on the subject and to organize it in an orderly fashion. The name, symptomatology, host range, and geographic distribution are given for each virus disease. Where it was possible illustrations of each disorder have also been included. This bulletin addresses the following apple virus diseases: apple mosaic, flat limb, rubbery wood, stem pitting, spy 227 apple reaction, dwarf fruit and decline, chat fruit, chlorotic leaf spot, leaf pucker, dapple apple, false sting and green crinkle, green mottle, ring spot, star cracking, scar skin, rough skin, apple proliferation, rosettehttps://digitalcommons.library.umaine.edu/aes_bulletin/1068/thumbnail.jp
Zooming In on the Progenitors of Superluminous Supernovae With the HST
We present Hubble Space Telescope (HST) rest-frame ultraviolet imaging of the
host galaxies of 16 hydrogen-poor superluminous supernovae (SLSNe), including
11 events from the Pan-STARRS Medium Deep Survey. Taking advantage of the
superb angular resolution of HST, we characterize the galaxies' morphological
properties, sizes and star formation rate (SFR) densities. We determine the
supernova (SN) locations within the host galaxies through precise astrometric
matching, and measure physical and host-normalized offsets, as well as the SN
positions within the cumulative distribution of UV light pixel brightness. We
find that the host galaxies of H-poor SLSNe are irregular, compact dwarf
galaxies, with a median half-light radius of just 0.9 kpc. The UV-derived SFR
densities are high ( ~ 0.1 M_sun/yr/kpc^2), suggesting that SLSNe
form in overdense environments. Their locations trace the UV light of their
host galaxies, with a distribution intermediate between that of long-duration
gamma-ray bursts (LGRBs) (which are strongly clustered on the brightest regions
of their hosts) and a uniform distribution (characteristic of normal
core-collapse SNe), though cannot be statistically distinguished from either
with the current sample size. Taken together, this strengthens the picture that
SLSN progenitors require different conditions than those of ordinary
core-collapse SNe to form, and that they explode in broadly similar galaxies as
do LGRBs. If the tendency for SLSNe to be less clustered on the brightest
regions than are LGRBs is confirmed by a larger sample, this would indicate a
different, potentially lower-mass progenitor for SLSNe than LRGBs.Comment: ApJ in press; matches published version. Minor changes following
referee's comments; conclusions unchange
Hydrogen-Poor Superluminous Supernovae and Long-Duration Gamma-Ray Bursts Have Similar Host Galaxies
We present optical spectroscopy and optical/near-IR photometry of 31 host
galaxies of hydrogen-poor superluminous supernovae (SLSNe), including 15 events
from the Pan-STARRS1 Medium Deep Survey. Our sample spans the redshift range
0.1 < z < 1.6 and is the first comprehensive host galaxy study of this specific
subclass of cosmic explosions. Combining the multi-band photometry and
emission-line measurements, we determine the luminosities, stellar masses, star
formation rates and metallicities. We find that as a whole, the hosts of SLSNe
are a low-luminosity ( ~ -17.3 mag), low stellar mass ( ~ 2 x 10^8
M_sun) population, with a high median specific star formation rate ( ~ 2
Gyr^-1). The median metallicity of our spectroscopic sample is low, 12 +
log(O/H}) ~ 8.35 ~ 0.45 Z_sun, although at least one host galaxy has solar
metallicity. The host galaxies of H-poor SLSNe are statistically distinct from
the hosts of GOODS core-collapse SNe (which cover a similar redshift range),
but resemble the host galaxies of long-duration gamma-ray bursts (LGRBs) in
terms of stellar mass, SFR, sSFR and metallicity. This result indicates that
the environmental causes leading to massive stars forming either SLSNe or LGRBs
are similar, and in particular that SLSNe are more effectively formed in low
metallicity environments. We speculate that the key ingredient is large core
angular momentum, leading to a rapidly-spinning magnetar in SLSNe and an
accreting black hole in LGRBs.Comment: ApJ in press; updated to match accepted version. Some additional data
added, discussion of selection effects expanded; conclusions unchanged. 22
pages in emulateapj forma
Direct observation of molecular cooperativity near the glass transition
We describe direct observations of molecular cooperativity near the glass
transition in poly-vinyl-acetate (PVAc), through nanometer-scale probing of
dielectric fluctuations. Molecular clusters switched spontaneously between two
to four distinct configurations, producing complex random-telegraph-signals
(RTS). Analysis of the RTS and their power spectra shows that individual
clusters exhibit both transient dynamical heterogeneity and non-exponential
kinetics.Comment: 14 pages pdf, need Acrobat Reade
Ultra-Luminous Supernovae as a New Probe of the Interstellar Medium in Distant Galaxies
We present the Pan-STARRS1 discovery and light curves, and follow-up MMT and
Gemini spectroscopy of an ultra-luminous supernova (ULSN; dubbed PS1-11bam) at
a redshift of z=1.566 with a peak brightness of M_UV=-22.3 mag. PS1-11bam is
one of the highest redshift spectroscopically-confirmed SNe known to date. The
spectrum is characterized by broad absorption features typical of previous
ULSNe (e.g., CII, SiIII), and by strong and narrow MgII and FeII absorption
lines from the interstellar medium (ISM) of the host galaxy, confirmed by an
[OII]3727 emission line at the same redshift. The equivalent widths of the
FeII2600 and MgII2803 lines are in the top quartile of the quasar intervening
absorption system distribution, but are weaker than those of gamma-ray burst
intrinsic absorbers (i.e., GRB host galaxies). We also detect the host galaxy
in pre-explosion Pan-STARRS1 data and find that its UV spectral energy
distribution is best fit with a young stellar population age of tau~15-45 Myr
and a stellar mass of M \sim (1.1-2.6)x10^9 M_sun (for Z=0.05-1 Z_sun). The
star formation rate inferred from the UV continuum and [OII]3727 emission line
is ~10 M_sun/yr, higher than in any previous ULSN host. PS1-11bam provides the
first direct demonstration that ULSNe can serve as probes of the interstellar
medium in distant galaxies. At the present, the depth and red sensitivity of
PS1 are uniquely suited to finding such events at cosmologically interesting
redshifts (z~1-2); the future combination of LSST and 30-m class telescopes
promises to extend this technique to z~4.Comment: Submitted to ApJL; 9 pages; 4 figures; 1 tabl
Cosmological Constraints from Measurements of Type Ia Supernovae discovered during the first 1.5 years of the Pan-STARRS1 Survey
We present griz light curves of 146 spectroscopically confirmed Type Ia
Supernovae () discovered during the first 1.5 years of the
Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is
determined by a combination of on-site measurements of the instrument response
function and observations of spectrophotometric standard stars. We find that
the systematic uncertainties in the photometric system are currently 1.2\%
without accounting for the uncertainty in the HST Calspec definition of the AB
system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia
that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113
PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only SNe and
assuming a constant dark energy equation of state and flatness, yields
.
When combined with BAO+CMB(Planck)+, the analysis yields and including all
identified systematics (see also Scolnic et al. 2014). The value of is
inconsistent with the cosmological constant value of at the 2.3
level. Tension endures after removing either the BAO or the constraint,
though it is strongest when including the constraint. If we include WMAP9
CMB constraints instead of those from Planck, we find
, which diminishes the discord to . We
cannot conclude whether the tension with flat CDM is a feature of dark
energy, new physics, or a combination of chance and systematic errors. The full
Pan-STARRS1 supernova sample with 3 times as many SNe should provide
more conclusive results.Comment: 38 pages, 16 figures, 14 tables, ApJ in pres
Systematic Uncertainties Associated with the Cosmological Analysis of the First Pan-STARRS1 Type Ia Supernova Sample
We probe the systematic uncertainties from 113 Type Ia supernovae (SNIa) in
the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of
low-redshift surveys. The companion paper by Rest et al. (2013) describes the
photometric measurements and cosmological inferences from the PS1 sample. The
largest systematic uncertainty stems from the photometric calibration of the
PS1 and low-z samples. We increase the sample of observed Calspec standards
from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II
calibration systems are compared and discrepancies up to ~0.02 mag are
recovered. We find uncertainties in the proper way to treat intrinsic colors
and reddening produce differences in the recovered value of w up to 3%. We
estimate masses of host galaxies of PS1 supernovae and detect an insignificant
difference in distance residuals of the full sample of 0.037\pm0.031 mag for
host galaxies with high and low masses. Assuming flatness in our analysis of
only SNe measurements, we find . With additional constraints from BAO,
CMB(Planck) and H0 measurements, we find and
(statistical and systematic errors added in
quadrature). Significance of the inconsistency with depends on whether
we use Planck or WMAP measurements of the CMB:
.Comment: 24 pages, 20 figures. Accepted by Ap
PESSTO monitoring of SN 2012hn: further heterogeneity among faint type I supernovae
We present optical and infrared monitoring data of SN 2012hn collected by the
Public ESO Spectroscopic Survey for Transient Objects (PESSTO). We show that SN
2012hn has a faint peak magnitude (MR ~ -15.7) and shows no hydrogen and no
clear evidence for helium in its spectral evolution. Instead, we detect
prominent Ca II lines at all epochs, which relates this transient to previously
described 'Ca-rich' or 'gap' transients. However, the photospheric spectra
(from -3 to +32 d with respect to peak) of SN 2012hn show a series of
absorption lines which are unique, and a red continuum that is likely intrinsic
rather than due to extinction. Lines of Ti II and Cr II are visible. This may
be a temperature effect, which could also explain the red photospheric colour.
A nebular spectrum at +150d shows prominent CaII, OI, CI and possibly MgI lines
which appear similar in strength to those displayed by core-collapse SNe. To
add to the puzzle, SN 2012hn is located at a projected distance of 6 kpc from
an E/S0 host and is not close to any obvious starforming region. Overall SN
2012hn resembles a group of faint H-poor SNe that have been discovered recently
and for which a convincing and consistent physical explanation is still
missing. They all appear to explode preferentially in remote locations offset
from a massive host galaxy with deep limits on any dwarf host galaxies,
favouring old progenitor systems. SN 2012hn adds heterogeneity to this sample
of objects. We discuss potential explosion channels including He-shell
detonations and double detonations of white dwarfs as well as peculiar
core-collapse SNe.Comment: 14 pages, 14 figures, accepted to MNRAS on 14/10/201
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