ABSTRACT
Samples of young Type Ia supernovae have shown ‘early excess’ emission in a few cases. Similar excesses are predicted by some explosion and progenitor scenarios and hence can provide ...important clues regarding the origin of thermonuclear supernovae. They are, however, only predicted to last up to the first few days following explosion. It is therefore unclear whether such scenarios are intrinsically rare or whether the relatively small sample size simply reflects the difficulty in obtaining sufficiently early detections. To that end, we perform toy simulations covering a range of survey depths and cadences, and investigate the efficiency with which young Type Ia supernovae are recovered. As input for our simulations, we use models that broadly cover the range of predicted luminosities. Based on our simulations, we find that in a typical 3 d cadence survey, only ∼10 per cent of Type Ia supernovae would be detected early enough to rule out the presence of an excess. A 2 d cadence, however, should see this increase to ∼15 per cent. We find comparable results from more detailed simulations of the Zwicky Transient Facility surveys. Using the recovery efficiencies from these detailed simulations, we investigate the number of young Type Ia supernovae expected to be discovered assuming some fraction of the population comes from scenarios producing an excess at early times. Comparing the results of our simulations to observations, we find that the intrinsic fraction of Type Ia supernovae with early flux excesses is $\sim 28^{+13}_{-11}{{\ \rm per\ cent}}$.
The analogue ring sampler: A front-end chip for ANTARES Feinstein, F.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
05/2003, Letnik:
504, Številka:
1-3
Journal Article, Conference Proceeding
Recenzirano
The ANTARES collaboration has undertaken to build a deep-sea neutrino telescope. The technique consists in deploying an array of photomultipliers arranged in a lattice near the sea bed at 2400m ...depth. The array detects Cherenkov light from muons produced by neutrino interactions in the sea water and the rock beneath. The neutrino direction and energy are obtained from the time of arrival of the Cherenkov light and from the light yield. These measurements are performed by the Analogue Ring Sampler, an Application Specific Integrated Circuit designed to read and digitise the photomultiplier signal. The chip has been implemented in the front-end electronics of ANTARES. This paper presents measurements of the chip performances in this environment.
Although low birth weight premature infants and parents are at high risk for adverse health outcomes, there is a paucity of studies that test early NICU interventions with parents to prevent the ...development of negative parent-infant interaction trajectories and to reduce hospital length of stay. Our objective was to evaluate the efficacy of an educational-behavioral intervention program (ie, Creating Opportunities for Parent Empowerment) that was designed to enhance parent-infant interactions and parent mental health outcomes for the ultimate purpose of improving child developmental and behavior outcomes.
A randomized, controlled trial was conducted with 260 families with preterm infants from 2001 to 2004 in 2 NICUs in the northeast United States. Parents completed self-administered instruments during hospitalization, within 7 days after infant discharge, and at 2 months' corrected age. Blinded observers rated parent-infant interactions in the NICU.
All participants received 4 intervention sessions of audiotaped and written materials. Parents in the Creating Opportunities for Parent Empowerment program received information and behavioral activities about the appearance and behavioral characteristics of preterm infants and how best to parent them. The comparison intervention contained information regarding hospital services and policies.
Parental stress, depression, anxiety, and beliefs; parent-infant interaction during the NICU stay; NICU length of stay; and total hospitalization were measured.
Mothers in the Creating Opportunities for Parent Empowerment program reported significantly less stress in the NICU and less depression and anxiety at 2 months' corrected infant age than did comparison mothers. Blinded observers rated mothers and fathers in the Creating Opportunities for Parent Empowerment program as more positive in interactions with their infants. Mothers and fathers also reported stronger beliefs about their parental role and what behaviors and characteristics to expect of their infants during hospitalization. Infants in the Creating Opportunities for Parent Empowerment program had a 3.8-day shorter NICU length of stay (mean: 31.86 vs 35.63 days) and 3.9-day shorter total hospital length of stay (mean: 35.29 vs 39.19 days) than did comparison infants.
A reproducible educational-behavioral intervention program for parents that commences early in the NICU can improve parent mental health outcomes, enhance parent-infant interaction, and reduce hospital length of stay.
In 2003 Dawson and Feinstein asked whether or not a Banach function algebra with dense invertible group can have a proper Shilov boundary. We give an example of a uniform algebra showing that this ...can happen, and investigate the properties of such algebras. We make some remarks on the topological stable rank of commutative, unital Banach algebras. In particular, we prove that \mathrm{tsr}(A) \geq \mathrm{tsr}(C(\Phi_A)) whenever A is approximately regular.
We review recent application specific integrated circuits developed for high energy neutrino, gamma ray and cosmic ray detectors, which share constraints of the same kind. We compare various ...technical concepts used to fulfil similar requirements. We suggest some ways which could be followed in the near future to answer the needs of next generation experiments.
The ANTARES undersea neutrino telescope will consist of an array of mooring lines carrying photomultiplier tubes enclosed in pressure resistant glass spheres (optical modules). They detect the ...Cherenkov light emitted by the muon produced by the charged current interaction of the parent neutrino. The data are transmitted to the shore through an electro-optical cable. Two ASICs have been developed in order to process the photomultiplier tube signals. The SPE_PSD chip discriminates between single-photoelectron pulses for which the integrated charge and the arrival time are measured, and more complex pulses to be processed by the ARS0 chip. The ARS0 is a five-channel 128-memory-cell 1GS/s analogue sampler, read out by a 1MHz ADC. This array of switched capacitors is equivalent to a 1GHz flash ADC of several orders of magnitude less power consumption. Since single-photoelectron pulses amount to 99% of the total, this dual path of the signal processing provides a strong reduction of the power consumption as well as of the amount of transmitted data.
We give a counterexample to a conjecture of S. E. Morris by showing that there is a compact plane set X such that R(X) has no nonzero, bounded point derivations but such that R(X) is not weakly ...amenable. We also give an example of a separable uniform algebra A such that every maximal ideal of A has a bounded approximate identity but such that A is not weakly amenable.
The Large Magellanic Cloud, a satellite galaxy of the Milky Way, has been observed with the High Energy Stereoscopic System (H.E.S.S.) above an energy of 100 billion electron volts for a deep ...exposure of 210 hours. Three sources of different types were detected: the pulsar wind nebula of the most energetic pulsar known, N 157B; the radio-loud supernova remnant N 132D; and the largest nonthermal x-ray shell, the superbubble 30 Dor C. The unique object SN 1987A is, unexpectedly, not detected, which constrains the theoretical framework of particle acceleration in very young supernova remnants. These detections reveal the most energetic tip of a γ-ray source population in an external galaxy and provide via 30 Dor C the unambiguous detection of γ-ray emission from a superbubble.
The measurement of an excess in the cosmic-ray electron spectrum between 300 and 800 GeV by the ATIC experiment has – together with the PAMELA detection of a rise in the positron fraction up to ...≈100 GeV – motivated many interpretations in terms of dark matter scenarios; alternative explanations assume a nearby electron source like a pulsar or supernova remnant. Here we present a measurement of the cosmic-ray electron spectrum with H.E.S.S. starting at 340 GeV. While the overall electron flux measured by H.E.S.S. is consistent with the ATIC data within statistical and systematic errors, the H.E.S.S. data exclude a pronounced peak in the electron spectrum as suggested for interpretation by ATIC. The H.E.S.S. data follow a power-law spectrum with spectral index of 3.0±0.1(stat.)± 0.3(syst.), which steepens at about 1 TeV.
Type Ia supernovae ( are used to determine the distance-redshift relation and build the Hubble diagram. Neglecting their host-galaxy peculiar velocities (PVs) may bias the measurement of cosmological ...parameters. The smaller the redshift, the larger the effect is. We used realistic simulations of observed by the Zwicky Transient Facility (ZTF) to investigate the effect of different methods of taking PVs into account. We studied the impact of neglecting galaxy PVs and their correlations in an analysis of the Hubble diagram. We find that it is necessary to use the PV full covariance matrix computed from the velocity power spectrum to take the sample variance into account. Considering the results we have obtained using simulations, we determine the PV systematic effects in the context of the ZTF SN Ia DR2 sample. We determine the PV impact on the intercept of the Hubble diagram, $a_B$, which is directly linked to the measurement of $H_0$. We show that not taking into account PVs and their correlations results in a shift in the $H_0$ value of about $1.0$ and a slight underestimation of the $H_0$ error bar.
PDF
