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

Trait Anxiety Is Associated with Negative Interpretations When Resolving Valence Ambiguity of Surprised Faces

The current research examines whether trait anxiety is associated with negative interpretation bias when resolving valence ambiguity of surprised faces. To further isolate the neuro-cognitive mechanism, we presented angry, happy, and surprised faces at broad, high, and low spatial frequency and asked participants to determine the valence of each face. High trait anxiety was associated with more negative interpretations of broad spatial frequency (i.e., intact) surprised faces. However, the modulation of trait anxiety on the negative interpretation of surprised faces disappeared at high and low spatial frequencies. The current study provides evidence that trait anxiety modulates negative interpretations of broad spatial frequency surprised faces. However, the negative interpretation of low spatial frequency surprised faces appears to be a robust default response that occurs regardless of individual differences in trait anxiety

Improving the LSST dithering pattern and cadence for dark energy studies

The Large Synoptic Survey Telescope (LSST) will explore the entire southern sky over 10 years starting in 2022 with unprecedented depth and time sampling in six filters, $ugrizy$. Artificial power on the scale of the 3.5 deg LSST field-of-view will contaminate measurements of baryonic acoustic oscillations (BAO), which fall at the same angular scale at redshift $z \sim 1$. Using the HEALPix framework, we demonstrate the impact of an "un-dithered" survey, in which $17\%$ of each LSST field-of-view is overlapped by neighboring observations, generating a honeycomb pattern of strongly varying survey depth and significant artificial power on BAO angular scales. We find that adopting large dithers (i.e., telescope pointing offsets) of amplitude close to the LSST field-of-view radius reduces artificial structure in the galaxy distribution by a factor of $\sim$10. We propose an observing strategy utilizing large dithers within the main survey and minimal dithers for the LSST Deep Drilling Fields. We show that applying various magnitude cutoffs can further increase survey uniformity. We find that a magnitude cut of $r < 27.3$ removes significant spurious power from the angular power spectrum with a minimal reduction in the total number of observed galaxies over the ten-year LSST run. We also determine the effectiveness of the observing strategy for Type Ia SNe and predict that the main survey will contribute $\sim$100,000 Type Ia SNe. We propose a concentrated survey where LSST observes one-third of its main survey area each year, increasing the number of main survey Type Ia SNe by a factor of $\sim$1.5, while still enabling the successful pursuit of other science drivers.Comment: 9 pages, 6 figures, published in SPIE proceedings; corrected typo in equation

From trust in caregivers' support to exploration : the role of openness to negative affect and self-regulation

Attachment theory assumes that trust in caregivers' support and exploration are closely related. Little research tried to investigate this link, nor focuses on mechanisms that might explain this association. The present studies examined whether trust is related to exploration through a serial indirect effect of openness to negative affect and self-regulation. In Study 1, 212 children, aged 8-13, completed questionnaires assessing trust, openness to negative affect, self-regulation and exploration. The results showed that trust predicted exploration, but only to the extent to which openness to negative affect and self-regulation were involved too. Study 2 refined these findings (n = 59, aged 9-12) using a behavioral measure of openness to negative affect and exploration, and with mother-reported self-regulation. Replicating this serial indirect effect of openness to negative affect and self-regulation with multiple informants and methods, the present studies advance our understanding of how trust might foster exploration in preadolescence

Type Ia Supernova Light Curve Inference: Hierarchical Bayesian Analysis in the Near Infrared

We present a comprehensive statistical analysis of the properties of Type Ia SN light curves in the near infrared using recent data from PAIRITEL and the literature. We construct a hierarchical Bayesian framework, incorporating several uncertainties including photometric error, peculiar velocities, dust extinction and intrinsic variations, for coherent statistical inference. SN Ia light curve inferences are drawn from the global posterior probability of parameters describing both individual supernovae and the population conditioned on the entire SN Ia NIR dataset. The logical structure of the hierarchical model is represented by a directed acyclic graph. Fully Bayesian analysis of the model and data is enabled by an efficient MCMC algorithm exploiting the conditional structure using Gibbs sampling. We apply this framework to the JHK_s SN Ia light curve data. A new light curve model captures the observed J-band light curve shape variations. The intrinsic variances in peak absolute magnitudes are: sigma(M_J) = 0.17 +/- 0.03, sigma(M_H) = 0.11 +/- 0.03, and sigma(M_Ks) = 0.19 +/- 0.04. We describe the first quantitative evidence for correlations between the NIR absolute magnitudes and J-band light curve shapes, and demonstrate their utility for distance estimation. The average residual in the Hubble diagram for the training set SN at cz > 2000 km/s is 0.10 mag. The new application of bootstrap cross-validation to SN Ia light curve inference tests the sensitivity of the model fit to the finite sample and estimates the prediction error at 0.15 mag. These results demonstrate that SN Ia NIR light curves are as effective as optical light curves, and, because they are less vulnerable to dust absorption, they have great potential as precise and accurate cosmological distance indicators.Comment: 24 pages, 15 figures, 4 tables. Accepted for publication in ApJ. Corrected typo, added references, minor edit

Early and Late-Time Observations of SN 2008ha: Additional Constraints for the Progenitor and Explosion

We present a new maximum-light optical spectrum of the the extremely low luminosity and exceptionally low energy Type Ia supernova (SN Ia) 2008ha, obtained one week before the earliest published spectrum. Previous observations of SN 2008ha were unable to distinguish between a massive star and white dwarf origin for the SN. The new maximum-light spectrum, obtained one week before the earliest previously published spectrum, unambiguously shows features corresponding to intermediate mass elements, including silicon, sulfur, and carbon. Although strong silicon features are seen in some core-collapse SNe, sulfur features, which are a signature of carbon/oxygen burning, have always been observed to be weak in such events. It is therefore likely that SN 2008ha was the result of a thermonuclear explosion of a carbon-oxygen white dwarf. Carbon features at maximum light show that unburned material is present to significant depths in the SN ejecta, strengthening the case that SN 2008ha was a failed deflagration. We also present late-time imaging and spectroscopy that are consistent with this scenario.Comment: ApJL, accepted. 5 pages, 3 figure

The NN2 Flux Difference Method for Constructing Variable Object Light Curves

We present a new method for optimally extracting point-source time variability information from a series of images. Differential photometry is generally best accomplished by subtracting two images separated in time, since this removes all constant objects in the field. By removing background sources such as the host galaxies of supernovae, such subtractions make possible the measurement of the proper flux of point-source objects superimposed on extended sources. In traditional difference photometry, a single image is designated as the ``template'' image and subtracted from all other observations. This procedure does not take all the available information into account and for sub-optimal template images may produce poor results. Given N total observations of an object, we show how to obtain an estimate of the vector of fluxes from the individual images using the antisymmetric matrix of flux differences formed from the N(N-1)/2 distinct possible subtractions and provide a prescription for estimating the associated uncertainties. We then demonstrate how this method improves results over the standard procedure of designating one image as a ``template'' and differencing against only that image.Comment: Accepted to AJ. To be published in November 2005 issue. 16 page, 2 figures, 2 tables. Source code available at http://www.ctio.noao.edu/essence/nn2