Constraining slow-roll inflation with WMAP and 2dF

We constrain slow-roll inflationary models using the recent WMAP data combined with data from the VSA, CBI, ACBAR and 2dF experiments. We find the slow-roll parameters to be $0 < \epsilon_1 < 0.032$ and $\epsilon_2 + 5.0 \epsilon_1 = 0.036 \pm 0.025$. For inflation models $V \propto \phi^{\alpha}$ we find that $\alpha< 3.9, 4.3$ at the 2$\sigma$ and $3\sigma$ levels, indicating that the $\lambda\phi^4$ model is under very strong pressure from observations. We define a convergence criterion to judge the necessity of introducing further power spectrum parameters such as the spectral index and running of the spectral index. This criterion is typically violated by models with large negative running that fit the data, indicating that the running cannot be reliably measured with present data.Comment: 8 pages RevTeX4 file with six figures incorporate

Deep CCD Surface Photometry of Galaxy Clusters I: Methods and Initial Studies of Intracluster Starlight

We report the initial results of a deep imaging survey of galaxy clusters. The primary goals of this survey are to quantify the amount of intracluster light as a function of cluster properties, and to quantify the frequency of tidal debris. We outline the techniques needed to perform such a survey, and we report findings for the first two galaxy clusters in the survey: Abell 1413, and MKW 7 . These clusters vary greatly in richness and structure. We show that our surface photometry reliably reaches to a surface brightness of \mu_v = 26.5 mags per arcsec. We find that both clusters show clear excesses over a best-fitting r^{1/4} profile: this was expected for Abell 1413, but not for MKW 7. Both clusters also show evidence of tidal debris in the form of plumes and arc-like structures, but no long tidal arcs were detected. We also find that the central cD galaxy in Abell 1413 is flattened at large radii, with an ellipticity of $\approx 0.8$, the largest measured ellipticity of any cD galaxy to date.Comment: 58 pages, 24 figures, accepted for publication in the Astrophysical Journal. Version has extremely low resolution figures to comply with 650k limit. High resolution version is available at http://burro.astr.cwru.edu/johnf/icl1.ps.gz Obtaining high resolution version is strongly reccomende

AMI-LA Observations of the SuperCLASS Super-cluster

We present a deep survey of the SuperCLASS super-cluster - a region of sky known to contain five Abell clusters at redshift $z\sim0.2$ - performed using the Arcminute Microkelvin Imager (AMI) Large Array (LA) at 15.5$~$GHz. Our survey covers an area of approximately 0.9 square degrees. We achieve a nominal sensitivity of $32.0~\mu$Jy beam$^{-1}$ toward the field centre, finding 80 sources above a $5\sigma$ threshold. We derive the radio colour-colour distribution for sources common to three surveys that cover the field and identify three sources with strongly curved spectra - a high-frequency-peaked source and two GHz-peaked-spectrum sources. The differential source count (i) agrees well with previous deep radio source count, (ii) exhibits no evidence of an emerging population of star-forming galaxies, down to a limit of 0.24$~$mJy, and (iii) disagrees with some models of the 15$~$GHz source population. However, our source count is in agreement with recent work that provides an analytical correction to the source count from the SKADS Simulated Sky, supporting the suggestion that this discrepancy is caused by an abundance of flat-spectrum galaxy cores as-yet not included in source population models.Comment: 17 pages, 14 figures, 3 tables. Accepted for publication in MNRA

AMI Large Array radio continuum observations of Spitzer c2d small clouds and cores

We perform deep 1.8 cm radio continuum imaging towards thirteen protostellar regions selected from the Spitzer c2d small clouds and cores programme at high resolution (25") in order to detect and quantify the cm-wave emission from deeply embedded young protostars. Within these regions we detect fifteen compact radio sources which we identify as radio protostars including two probable new detections. The sample is in general of low bolometric luminosity and contains several of the newly detected VeLLO sources. We determine the 1.8 cm radio luminosity to bolometric luminosity correlation, L_rad -L_bol, for the sample and discuss the nature of the radio emission in terms of the available sources of ionized gas. We also investigate the L_rad-L_IR correlation and suggest that radio flux density may be used as a proxy for the internal luminosity of low luminosity protostars.Comment: submitted MNRA

Suppressing the lower Multipoles in the CMB Anisotropies

The Cosmic Microwave Background (CMB) anisotropy power on the largest angular scales observed both by WMAP and COBE DMR appears to be lower than the one predicted by the standard model of cosmology with almost scale free primordial perturbations arising from a period of inflation \cite{cobe,Bennett:2003bz,Spergel,Peiris}. One can either interpret this as a manifestation of cosmic variance or as a physical effect that requires an explanation. We discuss various mechanisms that could be responsible for the suppression of such low $\ell$ multipoles. Features in the late time evolution of metric fluctuations may do this via the integral Sachs-Wolfe effect. Another possibility is a suppression of power at large scales in the primordial spectrum induced by a fast rolling stage in the evolution of the inflaton field at the beginning of the last 65 e-folds of inflation. We illustrate this effect in a simple model of inflation and fit the resulting CMB spectrum to the observed temperature-temperature (TT) power spectrum. We find that the WMAP observations suggest a cutoff at $k_c=4.9^{+1.3}_{-1.6}\times 10^{-4}$Mpc$^{-1}$ at 68% confidence, while only an upper limit of $k_c < 7.4\times 10^{-4}$Mpc$^{-1}$ at 95%. Thus, although it improves the fit of the data, the presence of a cutoff in power spectrum is only required at a level close to $2\sigma$. This is obtained with a prior which corresponds to equal distribution wrt $k_c$. We discuss how other choices (such as an equal distribution wrt $\ln k_c$ which is natural in the context of inflation) can affect the statistical interpretation.Comment: 11 pages, 4 figures, replaced with published version, comparison with recent papers is extende

Planck Intermediate Results II: Comparison of Sunyaev-Zeldovich measurements from Planck and from the Arcminute Microkelvin Imager for 11 galaxy clusters

A comparison is presented of Sunyaev-Zeldovich measurements for 11 galaxy clusters as obtained by Planck and by the ground-based interferometer, the Arcminute Microkelvin Imager. Assuming a universal spherically-symmetric Generalised Navarro, Frenk & White (GNFW) model for the cluster gas pressure profile, we jointly constrain the integrated Compton-Y parameter (Y_500) and the scale radius (theta_500) of each cluster. Our resulting constraints in the Y_500-theta_500 2D parameter space derived from the two instruments overlap significantly for eight of the clusters, although, overall, there is a tendency for AMI to find the Sunyaev-Zeldovich signal to be smaller in angular size and fainter than Planck. Significant discrepancies exist for the three remaining clusters in the sample, namely A1413, A1914, and the newly-discovered Planck cluster PLCKESZ G139.59+24.18. The robustness of the analysis of both the Planck and AMI data is demonstrated through the use of detailed simulations, which also discount confusion from residual point (radio) sources and from diffuse astrophysical foregrounds as possible explanations for the discrepancies found. For a subset of our cluster sample, we have investigated the dependence of our results on the assumed pressure profile by repeating the analysis adopting the best-fitting GNFW profile shape which best matches X-ray observations. Adopting the best-fitting profile shape from the X-ray data does not, in general, resolve the discrepancies found in this subset of five clusters. Though based on a small sample, our results suggest that the adopted GNFW model may not be sufficiently flexible to describe clusters universally.Comment: update to metadata author list onl

CMB Telescopes and Optical Systems

The cosmic microwave background radiation (CMB) is now firmly established as a fundamental and essential probe of the geometry, constituents, and birth of the Universe. The CMB is a potent observable because it can be measured with precision and accuracy. Just as importantly, theoretical models of the Universe can predict the characteristics of the CMB to high accuracy, and those predictions can be directly compared to observations. There are multiple aspects associated with making a precise measurement. In this review, we focus on optical components for the instrumentation used to measure the CMB polarization and temperature anisotropy. We begin with an overview of general considerations for CMB observations and discuss common concepts used in the community. We next consider a variety of alternatives available for a designer of a CMB telescope. Our discussion is guided by the ground and balloon-based instruments that have been implemented over the years. In the same vein, we compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). CMB interferometers are presented briefly. We conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and Planck, to demonstrate a remarkable evolution in design, sensitivity, resolution, and complexity over the past thirty years.Comment: To appear in: Planets, Stars and Stellar Systems (PSSS), Volume 1: Telescopes and Instrumentatio

Familial aggregation and heritability of schizophrenia and co-aggregation of psychiatric illnesses in affected families

Strong familial aggregation of schizophrenia has been reported but there is uncertainty concerning the degree of genetic contribution to the phenotypic variance of the disease. This study aimed to examine the familial aggregation and heritability of schizophrenia, and the relative risks (RRs) of other psychiatric diseases, in relatives of people with schizophrenia using the Taiwan National Health Insurance Database. The study population included individuals with affected first-degree or second-degree relatives identified from all beneficiaries (n = 23 422 955) registered in 2013. Diagnoses of schizophrenia made by psychiatrists were ascertained between January 1, 1996 and December 31, 2013. Having an affected co-twin, first-degree relative, second-degree relative, or spouse was associated with an adjusted RR (95% CI) of 37.86 (30.55-46.92), 6.30 (6.09-6.53), 2.44 (1.91-3.12), and 1.88 (1.64-2.15), respectively. Compared with the general population, individuals with one affected first-degree relative had a RR (95% CI) of 6.00 (5.79-6.22) and those with 2 or more had a RR (95% CI) of 14.66 (13.00-16.53) for schizophrenia. The accountability for the phenotypic variance of schizophrenia was 47.3% for genetic factors, 15.5% for shared environmental factors, and 37.2% for non-shared environmental factors. The RR (95% CI) in individuals with a first-degree relative with schizophrenia was 3.49 (3.34-3.64) for mood disorders and 3.91 (3.35-4.57) for delusional disorders. A family history of schizophrenia is therefore associated with a higher risk of developing schizophrenia, mood disorders, and delusional disorders. Heritability and environmental factors each account for half of the phenotypic variance of schizophrenia

Beyond handover: supporting awareness for continuous coverage

Abstract Hospitals are required to operate as a continuous system because patient care cannot be temporarily suspended and handover is seen as a key method for enabling this. This paper reports a study of handover in a medical admissions unit. We draw on the notion of awareness as conceptualised within the Computer Supported Cooperative Work literature to explore the role played by a variety of cognitive artifacts in supporting continuous coverage. While such awareness is typically characterised as being ‘effortless’, our study reveals that maintaining awareness in a context such as the medical admissions unit is effortful due to invisible work. We suggest that the notion of awareness is beneficial for exploring the practices of continuous coverage because it moves attention away from the moment of handover, instead encouraging consideration of the variety of practices through which clinicians display their work to, and monitor the work of, colleagues on different shifts. We argue that efforts to support continuous coverage should focus on improving awareness by increasing the visibility of information