4,378 research outputs found
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SweetSpot: Near-Infrared Observations of Thirteen Type Ia Supernovae from a New NOAO Survey Probing the Nearby Smooth Hubble Flow
We present 13 Type Ia supernovae (SNe Ia) observed in the restframe
near-infrared (NIR) from 0.02 < z < 0.09 with the WIYN High-resolution Infrared
Camera (WHIRC) on the WIYN 3.5-m telescope. With only 1-3 points per light
curve and a prior on the time of maximum from the spectrum used to type the
object we measure an H-band dispersion of spectroscopically normal SNe Ia of
0.164 mag. These observations continue to demonstrate the improved standard
brightness of SNe Ia in H-band even with limited data. Our sample includes two
SNe Ia at z ~ 0.09, which represent the most distant restframe NIR H-band
observations published to date.
This modest sample of 13 NIR SNe Ia represent the pilot sample for
"SweetSpot" - a three-year NOAO Survey program that will observe 144 SNe Ia in
the smooth Hubble flow. By the end of the survey we will have measured the
relative distance to a redshift of z ~ 0.05 to 1%. Nearby Type Ia supernova (SN
Ia) observations such as these will test the standard nature of SNe Ia in the
restframe NIR, allow insight into the nature of dust, and provide a critical
anchor for future cosmological SN Ia surveys at higher redshift.Comment: 36 pages, 8 figures, Submitted to Ap
¿Qué es el idealismo transcendental?
Se discuten dos interpretaciones del idealismo transcendental de Kant: la interpretación de la causalidad, para la que los fenómenos y las cosas reales son distintos, y la interpretación de la identidad, que los identifica. Ambas interpretaciones tienen base textual, pero filosóficamente es superior y preferible la segund
The First Data Release from SweetSpot: 74 Supernovae in 36 Nights on WIYN+WHIRC
SweetSpot is a three-year National Optical Astronomy Observatory (NOAO)
Survey program to observe Type Ia supernovae (SNe Ia) in the smooth Hubble flow
with the WIYN High-resolution Infrared Camera (WHIRC) on the WIYN 3.5-m
telescope. We here present data from the first half of this survey, covering
the 2011B-2013B NOAO semesters, and consisting of 493 calibrated images of 74
SNe Ia observed in the rest-frame near-infrared (NIR) from .
Because many observed supernovae require host galaxy subtraction from templates
taken in later semesters, this release contains only the 186 NIR () data
points for the 33 SNe Ia that do not require host-galaxy subtraction. The
sample includes 4 objects with coverage beginning before the epoch of B-band
maximum and 27 beginning within 20 days of B-band maximum. We also provide
photometric calibration between the WIYN+WHIRC and Two-Micron All Sky Survey
(2MASS) systems along with light curves for 786 2MASS stars observed alongside
the SNe Ia. This work is the first in a planned series of three SweetSpot Data
Releases. Future releases will include the full set of images from all 3 years
of the survey, including host-galaxy reference images and updated data
processing and host-galaxy reference subtraction. SweetSpot will provide a
well-calibrated sample that will help improve our ability to standardize
distance measurements to SNe Ia, examine the intrinsic optical-NIR colors of
SNe Ia at different epochs, explore nature of dust in other galaxies, and act
as a stepping stone for more distant, potentially space-based surveys.Comment: Published in AJ. 10 tables. 11 figures. Lightcurve plots included as
a figureset and available in source tarball. Data online at
http://www.phyast.pitt.edu/~wmwv/SweetSpot/DR1_data
Phomopsis-resistanct lupins : breakthrough towards the control of lupinosis
Attemots to control lupinosis in sheep have been thwarted by the unpredictable occurence of the disease in the field. The complex interaction of the toxin-producing fungus (Phomopsis leptostromiformis) with its host (the lupin plant), together with variable weather and paddock grazing conditions, have made it difficult to predict when stock are in danger of contracting the disease. The risk of lupinosis discourages many farmers from growing lupins, despite the many potential benefits of including them in crop rotations.
A team of Department of Agriculture plant breeders, plant pathologists, and animal scientists set out in the mid 1970s to find resistance to the Phomopsis fungus in lupins. Their goal was to find resistance that prevented the fungus from colonising and producing toxin in lupin stubbles. A decade of work has culminated in the development of lupin breeding lines with low visible symptoms of Phomopsis in the stubble and, most importantly, low stubble toxixity. This article summarises the long-term research programme
Long-term tropospheric formaldehyde concentrations deduced from ground-based fourier transform solar infrared measurements
We report a 13-year (1992–2005) dataset of total column measurements of formaldehyde (HCHO) over Lauder, New Zealand, inferred from solar infrared spectra measured using a high-resolution Fourier Transform Spectrometer (FTS). Ambient HCHO concentrations at this rural location are often close to levels typical of remote marine environments (\u3c250 ppt), which are close to the detection limit using standard techniques. Consequently we develop a new method that successfully produces HCHO columns with sufficient sensitivity throughout the whole season. HCHO columns over Lauder have a strong seasonal cycle (±50%), with a mean column of 4.9×1015 molecules cm−2, peaking during summer months. A simple box model of CH4 oxidation reproduces the observed broad-scale seasonal cycle, but significantly underestimates the seasonal peak HCHO ground concentrations during summer. This suggests the existence of an additional significant source of HCHO, possibly isoprene that cannot be explained by oxidation of CH4 alone. The ground-based FTS column data compare well with collocated HCHO column measurements from the Global Ozone Monitoring Experiment (GOME) satellite instrument during the operational period of GOME (1996–2001, r2=0.65, mean bias=10%, n=48)
Improved constraints on dark energy from Chandra X-ray observations of the largest relaxed galaxy clusters
We present constraints on the mean matter density, Omega_m, dark energy
density, Omega_de, and the dark energy equation of state parameter, w, using
Chandra measurements of the X-ray gas mass fraction (fgas) in 42 hot (kT>5keV),
X-ray luminous, dynamically relaxed galaxy clusters spanning the redshift range
0.05<z<1.1. Using only the fgas data for the 6 lowest redshift clusters at
z<0.15, for which dark energy has a negligible effect on the measurements, we
measure Omega_m=0.28+-0.06 (68% confidence, using standard priors on the Hubble
Constant, H_0, and mean baryon density, Omega_bh^2). Analyzing the data for all
42 clusters, employing only weak priors on H_0 and Omega_bh^2, we obtain a
similar result on Omega_m and detect the effects of dark energy on the
distances to the clusters at ~99.99% confidence, with Omega_de=0.86+-0.21 for a
non-flat LCDM model. The detection of dark energy is comparable in significance
to recent SNIa studies and represents strong, independent evidence for cosmic
acceleration. Systematic scatter remains undetected in the fgas data, despite a
weighted mean statistical scatter in the distance measurements of only ~5%. For
a flat cosmology with constant w, we measure Omega_m=0.28+-0.06 and
w=-1.14+-0.31. Combining the fgas data with independent constraints from CMB
and SNIa studies removes the need for priors on Omega_bh^2 and H_0 and leads to
tighter constraints: Omega_m=0.253+-0.021 and w=-0.98+-0.07 for the same
constant-w model. More general analyses in which we relax the assumption of
flatness and/or allow evolution in w remain consistent with the cosmological
constant paradigm. Our analysis includes conservative allowances for systematic
uncertainties. The small systematic scatter and tight constraints bode well for
future dark energy studies using the fgas method. (Abridged)Comment: Published in MNRAS. 20 pages, 11 figures. The data and analysis code
(in the form of a patch to CosmoMC) are now available at
http://www.stanford.edu/~drapetti/fgas_module
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