Lyman-tomography of cosmic infrared background fluctuations with Euclid: probing emissions and baryonic acoustic oscillations at z>10

The Euclid space mission, designed to probe evolution of the Dark Energy, will map a large area of the sky at three adjacent near-IR filters, Y, J and H. This coverage will also enable mapping source-subtracted cosmic infrared background (CIB) fluctuations with unprecedented accuracy on sub-degree angular scales. Here we propose methodology, using the Lyman-break tomography applied to the Euclid-based CIB maps, to accurately isolate the history of CIB emissions as a function of redshift from 10 < z < 20, and to identify the baryonic acoustic oscillations (BAOs) at those epochs. To identify the BAO signature, we would assemble individual CIB maps over conservatively large contiguous areas of >~ 400 sq deg. The method can isolate the CIB spatial spectrum by z to sub-percent statistical accuracy. We illustrate this with a specific model of CIB production at high z normalized to reproduce the measured Spitzer-based CIB fluctuation. We show that even if the latter contain only a small component from high-z sources, the amplitude of that component can be accurately isolated with the methodology proposed here and the BAO signatures at z>~ 10 are recovered well from the CIB fluctuation spatial spectrum. Probing the BAO at those redshifts will be an important test of the underlying cosmological paradigm, and would narrow the overall uncertainties on the evolution of cosmological parameters, including the Dark Energy. Similar methodology is applicable to the planned WFIRST mission, where we show that a possible fourth near-IR channel at > 2 micron would be beneficial.Comment: comments welcom

On Kostant's partial order on hyperbolic elements

We study Kostant's partial order on the elements of a semisimple Lie group in relations with the finite dimensional representations. In particular, we prove the converse statement of [3, Theorem 6.1] on hyperbolic elements.Comment: 7 page

Wigner transform and pseudodifferential operators on symmetric spaces of non-compact type

We obtain a general expression for a Wigner transform (Wigner function) on symmetric spaces of non-compact type and study the Weyl calculus of pseudodifferential operators on them

Identifying obstacles to participation in a questionnaire survey on widowers' grief

Background: The aim of this study was to determine if Icelandic widowers might foresee obstacles to responding to a questionnaire on bereavement. Also, we sought to compare the proportion of men reporting obstacles in a telephone interview to the actual response rate in the questionnaire survey. Methods: The study was part of a nation-wide survey of widowers who lost their wives in 1999, 2000, and 2001. This included all widowers born in Iceland 1924-1969 (aged 30-75 years) who were alive, and residing in Iceland at the time of the study. A telephone poll was conducted prior to sending out a questionnaire to determine if the widowers would be interested in responding, or if they could see obstacles, which could affect their willingness to respond to a subsequent questionnaire survey. The telephone poll was repeated five years later with a random sample of the original study base to determine if views initially expressed towards the questionnaire survey, had changed over time. Results: Of the 357 eligible widowers, 11 had died prior to the first telephone interview, yielding a study population of 346 widowers. Of those, 296 (86%) were reachable and all of these (100%) were willing to participate in the telephone survey. Of them, 55% identified obstacles to participation in the questionnaire survey. Men under 60 years were less likely to identify obstacles. Years from loss (second through fourth years) were not associated with reporting obstacles to participation. The response rate in the epidemiological questionnaire survey following the telephone interview was 62% (216/346). Of those who did identify obstacles 23%, did not did not identify any particular obstacle, but 33% stated that "they felt bad" or that it would be "a painful experience" or that they felt "uncomfortable" talking about their grief. About 18% stated their grief was "a private matter"; 6% stated that they did not want to be "stuck with their grief"; 9% said that it was "too late" to talk about their grief or that they "wanted to look towards their future". Additionally, 11% stated "other reasons", including responses like: "it's too early to talk about it", and "I have started another relationship - don't want complications." Conclusions: The willingness to participate in the telephone interview was high and indicates a strong interest in the subject. Also, exposure to the study appeared to increase willingness to participate, since many men who initially could see obstacles to participation, actually participated in the epidemiological questionnaire survey. However, approximately one third of the men who initially identified obstacles to participation remained negative toward participation throughout the study period.NonePublishe

Social correlates of cigarette smoking among Icelandic adolescents: A population-based cross-sectional study

BACKGROUND: Previous research has shown that between 80 and 90 percent of adult smokers report having started smoking before 18 years of age. Several studies have revealed that multiple social factors influence the likelihood of smoking during adolescence, the period during which the onset of smoking usually occurs. To better understand the social mechanisms that influence adolescent smoking, we analyzed the relationship and relative importance of a broad spectrum of social variables in adolescent smoking in Iceland, a Nordic country with high per-capita income. METHODS: We used cross-sectional data from 7,430 14- to 16 year-old students (approximately 81% of all Icelanders in these age cohorts) in the 2006 Youth in Iceland study. The Youth in Iceland studies are designed to investigate the role of several cognitive, behavioral, and social factors in the lives of adolescents, and the data collected are used to inform the design, implementation, and evaluation of substance use prevention programs that are being developed by Icelandic social scientists, policy makers, and practitioners. RESULTS: Our analysis revealed that friends' smoking behavior and attitude toward smoking were strongly associated with adolescent smoking and other tobacco use, as well as alcohol consumption during the previous 30 days. Main protective factors were parent's perceived attitude toward smoking, the quantity of time spent with parents, absence of serious verbal conflict between parents and adolescents, and participation in physical activity. Family structure was related to adolescent smoking to a small extent, but other background factors were not. CONCLUSION: We conclude that multiple social factors are related to adolescent smoking. Parents and other primary preventive agents need to be informed about the complicated nature of the adolescent social world in order to maximize their impact.Icelandic Alcohol and Drug Prevention CommitteeIcelandic Red CrossCity of ReykjavikSports and Recreational Committee of Reykjavik to the Icelandic Centre for Social Research and AnalysisIcelandic Centre for Research (RANNÍS)Publishe

On the solution of the initial value constraints for general relativity coupled to matter in terms of Ashtekar's variables

The method of solution of the initial value constraints for pure canonical gravity in terms of Ashtekar's new canonical variables due to CDJ is further developed in the present paper. There are 2 new main results : 1) We extend the method of CDJ to arbitrary matter-coupling again for non-degenerate metrics : the new feature is that the 'CDJ-matrix' adopts a nontrivial antisymmetric part when solving the vector constraint and that the Klein-Gordon-field is used, instead of the symmetric part of the CDJ-matrix, in order to satisfy the scalar constraint. 2) The 2nd result is that one can solve the general initial value constraints for arbitrary matter coupling by a method which is completely independent of that of CDJ. It is shown how the Yang-Mills and gravitational Gauss constraints can be solved explicitely for the corresponding electric fields. The rest of the constraints can then be satisfied by using either scalar or spinor field momenta. This new trick might be of interest also for Yang-Mills theories on curved backgrounds.Comment: Latex, 15 pages, PITHA93-1, January 9

Reconstructing emission from pre-reionization sources with cosmic infrared background fluctuation measurements by the JWST

We present new methodology to use cosmic infrared background (CIB) fluctuations to probe sources at 10<z<30 from a JWST/NIRCam configuration that will isolate known galaxies to 28 AB mag at 0.5--5 micron. At present significant mutually consistent source-subtracted CIB fluctuations have been identified in the Spitzer and Akari data at 2--5 micron, but we demonstrate internal inconsistencies at shorter wavelengths in the recent CIBER data. We evaluate CIB contributions from remaining galaxies and show that the bulk of the high-z sources will be in the confusion noise of the NIRCam beam, requiring CIB studies. The accurate measurement of the angular spectrum of the fluctuations and probing the dependence of its clustering component on the remaining shot noise power would discriminate between the various currently proposed models for their origin and probe the flux distribution of its sources. We show that the contribution to CIB fluctuations from remaining galaxies is large at visible wavelengths for the current instruments precluding probing the putative Lyman-break of the CIB fluctuations. We demonstrate that with the proposed JWST configuration such measurements will enable probing the Lyman break. We develop a Lyman-break tomography method to use the NIRCam wavelength coverage to identify or constrain, via the adjacent two-band subtraction, the history of emissions over 10<z<30 as the Universe comes out of the 'Dark Ages'. We apply the proposed tomography to the current Spitzer/IRAC measurements at 3.6 and 4.5 micron, to find that it already leads to interestingly low upper limit on emissions at z>30.Comment: ApJ, in press. Minor revisions/additions to match the version in proof

Operator Product on Locally Symmetric Spaces of Rank One and the Multiplicative Anomaly

The global multiplicative properties of Laplace type operators acting on irreducible rank one symmetric spaces are considered. The explicit form of the multiplicative anomaly is derived and its corresponding value is calculated exactly, for important classes of locally symmetric spaces and different dimensions.Comment: Int. Journal of Modern Physics A, vol. 18 (2003), 2179-218

Space-time symplectic extension

It is conjectured that in the origin of space-time there lies a symplectic rather than metric structure. The complex symplectic symmetry Sp(2l,C), l\ge1 instead of the pseudo-orthogonal one SO(1,d-1), d\ge4 is proposed as the space-time local structure group. A discrete sequence of the metric space-times of the fixed dimensionalities d=(2l)^2 and signatures, with l(2l-1) time-like and l(2l+1) space-like directions, defined over the set of the Hermitian second-rank spin-tensors is considered as an alternative to the pseudo-Euclidean extra dimensional space-times. The basic concepts of the symplectic framework are developed in general, and the ordinary and next-to-ordinary space-time cases with l=1,2, respectively, are elaborated in more detail. In particular, the scheme provides the rationale for the four-dimensionality and 1+3 signature of the ordinary space-time.Comment: 15 pp, LaTe