We describe catalog-level simulations of Type Ia Supernova (SN Ia) light curves in the Dark Energy Survey Supernova Program (DES-SN), and in low-redshift samples from the Center for Astrophysics ...(CfA) and the Carnegie Supernova Project (CSP). These simulations are used to model biases from selection effects and light curve analysis, and to determine bias corrections for SN Ia distance moduli that are used to measure cosmological parameters. To generate realistic light curves the simulation uses a detailed SN Ia model, incorporates information from observations (PSF, sky noise, zero point), and uses summary information (e.g., detection efficiency vs. signal to noise ratio) based on 10,000 fake SN light curves whose fluxes were overlaid on images and processed with our analysis pipelines. The quality of the simulation is illustrated by predicting distributions observed in the data. Averaging within redshift bins, we find distance modulus biases up to 0.05 mag over the redshift ranges of the low-z and DES-SN samples. For individual events, particularly those with extreme red or blue color, distance biases can reach 0.4 mag. Therefore, accurately determining bias corrections is critical for precision measurements of cosmological parameters. Files used to make these corrections are available at https://des.ncsa.illinois.edu/releases/sn.
Many scientific goals for the Dark Energy Survey (DES) require the calibration of optical/NIR broadband b = grizY photometry that is stable in time and uniform over the celestial sky to one percent ...or better. It is also necessary to limit to similar accuracy systematic uncertainty in the calibrated broadband magnitudes due to uncertainty in the spectrum of the source. Here we present a "Forward Global Calibration Method (FGCM)" for photometric calibration of the DES, and we present results of its application to the first three years of the survey (Y3A1). The FGCM combines data taken with auxiliary instrumentation at the observatory with data from the broadband survey imaging itself and models of the instrument and atmosphere to estimate the spatial and time dependences of the passbands of individual DES survey exposures. "Standard" passbands that are typical of the passbands encountered during the survey are chosen. The passband of any individual observation is combined with an estimate of the source spectral shape to yield a magnitude in the standard system. This "chromatic correction" to the standard system is necessary to achieve subpercent calibrations and in particular, to resolve ambiguity between the broadband brightness of a source and the shape of its SED. The FGCM achieves a reproducible and stable photometric calibration of standard magnitudes of stellar sources over the multiyear Y3A1 data sample with residual random calibration errors of per exposure. The accuracy of the calibration is uniform across the DES footprint to within . The systematic uncertainties of magnitudes in the standard system due to the spectra of sources are less than for main-sequence stars with .
We present griz light curves of 251 SNe Ia from the first 3 years of the Dark Energy Survey Supernova Program's (DES-SN) spectroscopically classified sample. The photometric pipeline described in ...this paper produces the calibrated fluxes and associated uncertainties used in the cosmological parameter analysis by employing a scene modeling approach that simultaneously models a variable transient flux and temporally constant host galaxy. We inject artificial point sources onto DECam images to test the accuracy of our photometric method. Upon comparison of input and measured artificial supernova fluxes, we find that flux biases peak at 3 mmag. We require corrections to our photometric uncertainties as a function of host galaxy surface brightness at the transient location, similar to that seen by the DES Difference Imaging Pipeline used to discover transients. The public release of the light curves can be found at https://des.ncsa.illinois.edu/releases/sn.
Abstract We present cosmological analysis of 12 nearby ( z < 0.06) Type IIP supernovae (SNe IIP) observed with the ROTSE-IIIb telescope. To achieve precise photometry, we present a new ...image-differencing technique that is implemented for the first time on the ROTSE SN photometry pipeline. With this method, we find up to a 20% increase in the detection efficiency and significant reduction in residual rms scatter of the SN lightcurves when compared to the previous pipeline performance. We use the published optical spectra and broadband photometry of well-studied SNe IIP to establish temporal models for ejecta velocity and photospheric temperature evolution for our SNe IIP population. This study yields measurements that are competitive with other methods even when the data are limited to a single epoch during the photospheric phase of SNe IIP. Using the fully reduced ROTSE photometry and optical spectra, we apply these models to the respective photometric epochs for each SN in the ROTSE IIP sample. This facilitates the use of the Expanding Photosphere Method (EPM) to obtain distance estimates to their respective host galaxies. We then perform cosmological parameter fitting using these EPM distances, from which we measure the Hubble constant to be 72.9 − 4.3 + 5.7 km s − 1 Mpc − 1 , which is consistent with the standard ΛCDM model values derived using other independent techniques.
Hasdai Crescas fue un importante pensador, autor y líder comunitario judío de finales del siglo XIV y principios del XV, cuyas obras son estudiadas con detalle en el mundo académico. No obstante, su ...impacto sobre la comunidad judía tradicional ha sido casi inexistente. Nunca terminó su obra legal, la que podría haber tenido impacto en los judíos tradicionales. Sus escritos filosóficos conservados son difíciles de seguir; solo sobrevive una de las dos polémicas anticristianas vernáculas, en una traducción/paráfrasis hebrea. Aunque Crescas fue bien recordado en el siglo posterior a su muerte, ya en este período se pueden detectar las razones de su posterior olvido. Un examen de la historia de la recepción de la obra de Crescas en el siglo XV demuestra hasta qué punto sus posiciones polémicas, dogmáticas y filosóficas fueron mayoritariamente rechazadas, más allá de que tuvo partidarios, fundamentalmente entre sus alumnos más cercanos. No es de extrañar, entonces, que en los siglos posteriores, la memoria de Crescas fuera casi borrada de la conciencia comunitaria judía.
Abstract
Calibration uncertainties have been the leading systematic uncertainty in recent analyses using Type Ia supernovae (SNe Ia) to measure cosmological parameters. To improve the calibration, we ...present the application of spectral energy distribution-dependent ‘chromatic corrections’ to the SN light-curve photometry from the Dark Energy Survey (DES). These corrections depend on the combined atmospheric and instrumental transmission function for each exposure, and they affect photometry at the 0.01 mag (1 per cent) level, comparable to systematic uncertainties in calibration and photometry. Fitting our combined DES and low-z SN Ia sample with baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) priors for the cosmological parameters Ωm (the fraction of the critical density of the universe comprised of matter) and w (the dark energy equation of state parameter), we compare those parameters before and after applying the corrections. We find the change in w and Ωm due to not including chromatic corrections is −0.002 and 0.000, respectively, for the DES-SN3YR sample with BAO and CMB priors, consistent with a larger DES-SN3YR-like simulation, which has a w-change of 0.0005 with an uncertainty of 0.008 and an Ωm change of 0.000 with an uncertainty of 0.002. However, when considering samples on individual CCDs we find large redshift-dependent biases (∼0.02 in distance modulus) for SN distances.
Abstract
Wavelength-dependent atmospheric effects impact photometric supernova flux measurements for ground-based observations. We present corrections on supernova flux measurements from the Dark ...Energy Survey Supernova Program’s 5YR sample (DES-SN5YR) for differential chromatic refraction (DCR) and wavelength-dependent seeing, and we show their impact on the cosmological parameters
w
and Ω
m
. We use
g
−
i
colors of Type Ia supernovae to quantify astrometric offsets caused by DCR and simulate point-spread functions (PSFs) using the GalSIM package to predict the shapes of the PSFs with DCR and wavelength-dependent seeing. We calculate the magnitude corrections and apply them to the magnitudes computed by the DES-SN5YR photometric pipeline. We find that for the DES-SN5YR analysis, not accounting for the astrometric offsets and changes in the PSF shape cause an average bias of +0.2 mmag and −0.3 mmag, respectively, with standard deviations of 0.7 mmag and 2.7 mmag across all DES observing bands (
griz
) throughout all redshifts. When the DCR and seeing effects are not accounted for, we find that
w
and Ω
m
are lower by less than 0.004 ± 0.02 and 0.001 ± 0.01, respectively, with 0.02 and 0.01 being the 1
σ
statistical uncertainties. Although we find that these biases do not limit the constraints of the DES-SN5YR sample, future surveys with much higher statistics, lower systematics, and especially those that observe in the
u
band will require these corrections as wavelength-dependent atmospheric effects are larger at shorter wavelengths. We also discuss limitations of our method and how they can be better accounted for in future surveys.
The microsomal metabolism of fentanyl, a synthetic opioid commonly used in anesthesia, was investigated in human liver. Incubation of fentanyl with human hepatic microsomes fortified with NADPH ...resulted in the formation of a single major metabolite, namely norfentanyl, as determined by GC/MS. No evidence was obtained for the formation of either desproprionylfentanyl or N-phenylpropionamide, the latter arising via N-dealkylation of the fentanyl amide nitrogen. Kinetic analysis of microsomal fentanyl oxidation revealed a single K(m) of 117 microM and a Vmax of 3.86 nmol of norfentanyl formed/min/nmol of cytochrome P450 (P450). Studies using chemical inhibitors of human P450 enzymes revealed that only agents known to inhibit CYP3A4 (e.g. ketoconazole and erythromycin) were capable of strongly inhibiting (> or = 90%) microsomal fentanyl oxidation. Marked inhibition (> 90%) of norfentanyl formation by liver microsomes was also observed with polyclonal antibodies to CYP3A4, whereas antibodies to other human P450s were without effect. Furthermore, rates of norfentanyl production by 10 individual human liver samples were highly correlated (r2 = 0.876, F = 56.46 p < 0.001) with immunochemically determined levels of CYP3A4 present in the samples but not with levels of CYP2C8, CYP2C9, CYP2C19, or CYP2E1. Our results indicate that CYP3A4 is the major catalyst involved in fentanyl oxidation to norfentanyl in human liver. Alterations in CYP3A4 levels or activity, as well as the concomitant administration of other therapeutic agents metabolized by this P450 enzyme, could lead to marked perturbations in fentanyl disposition and, hence, analgesic response.
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