We present constraints on the tensor-to-scalar ratio
r
using
Planck
data. We use the latest release of
Planck
maps, processed with the
NPIPE
code, which produces calibrated frequency maps in ...temperature and polarisation for all
Planck
channels from 30 GHz to 857 GHz using the same pipeline. We computed constraints on
r
using the
BB
angular power spectrum, and we also discuss constraints coming from the
TT
spectrum. Given
Planck
’s noise level, the
TT
spectrum gives constraints on
r
that are cosmic-variance limited (with
σ
r
= 0.093), but we show that the marginalised posterior peaks towards negative values of
r
at about the 1.2
σ
level. We derived
Planck
constraints using the
BB
power spectrum at both large angular scales (the ‘reionisation bump’) and intermediate angular scales (the ‘recombination bump’) from
ℓ
= 2 to 150 and find a stronger constraint than that from
TT
, with
σ
r
= 0.069. The
Planck
BB
spectrum shows no systematic bias and is compatible with zero, given both the statistical noise and the systematic uncertainties. The likelihood analysis using
B
modes yields the constraint
r
< 0.158 at 95% confidence using more than 50% of the sky. This upper limit tightens to
r
< 0.069 when
Planck
EE
,
BB
, and
EB
power spectra are combined consistently, and it tightens further to
r
< 0.056 when the
Planck
TT
power spectrum is included in the combination. Finally, combining
Planck
with BICEP2/Keck 2015 data yields an upper limit of
r
< 0.044.
We present constraints on the tensor-to-scalar ratio r using a combination of BICEP/Keck 2018 (BK18) and Planck PR4 data allowing us to fit for r consistently with the six parameters of the ΛCDM ...model. We discuss the sensitivity of constraints on r to uncertainties in the ΛCDM parameters as defined by the Planck data. In particular, we are able to derive a constraint on the reionization optical depth τ and thus propagate its uncertainty into the posterior distribution for r. While Planck sensitivity to r is slightly lower than the current ground-based measurements, the combination of Planck with BK18 and baryon-acoustic-oscillation data yields results consistent with r=0 and tightens the constraint to r<0.032 at 95% confidence.
We combine Planck High Frequency Instrument data at 857, 545, 353 and 217 GHz with data from Wide-field Infrared Survey Explorer (WISE), Spitzer, IRAS and Herschel to investigate the properties of a ...well-defined, flux-limited sample of local star-forming galaxies. A 545 GHz flux density limit was chosen so that the sample is 80 per cent complete at this frequency, and the resulting sample contains a total of 234 local, star-forming galaxies. We investigate the dust emission and star formation properties of the sample via various models and calculate the local dust mass function. Although single-component-modified blackbodies fit the dust emission longward of 80 μm very well, with a median β = 1.83, the known degeneracy between dust temperature and β also means that the spectral energy distributions are very well described by a dust component with dust emissivity index fixed at β = 2 and temperature in the range 10-25 K. Although a second, warmer dust component is required to fit shorter wavelength data, and contributes approximately a third of the total infrared emission, its mass is negligible. No evidence is found for a very cold (6-10 K) dust component. The temperature of the cold dust component is strongly influenced by the ratio of the star formation rate to the total dust mass. This implies, contrary to what is often assumed, that a significant fraction of even the emission from ∼20 K dust is powered by ongoing star formation, whether or not the dust itself is associated with star-forming clouds or 'cirrus'. There is statistical evidence of a free-free contribution to the 217 GHz flux densities of 20 per cent. We find a median dust-to-stellar mass ratio of 0.0046; and that this ratio is anticorrelated with galaxy mass. There is good correlation between dust mass and atomic gas mass (median M
d
M
HI
= 0.022), suggesting that galaxies that have more dust (higher values of M
d/M
*) have more interstellar medium in general. Our derived dust mass function implies a mean dust mass density of the local Universe (for dust within galaxies), of 7.0 ± 1.4 × 105 M Mpc−3, significantly greater than that found in the most recent estimate using Herschel data.
We present polarization data for 180 extragalactic sources extracted from the Australia Telescope 20 GHz (AT20G) survey catalogue and observed with the Australia Telescope Compact Array during a ...dedicated, high sensitivity run (... 1 mJy). For the sake of completeness, we extracted the polarization information for seven extended sources from the 9 yr Wilkinson Microwave Anisotropy Probe co-added maps at 23 GHz. The full sample of 187 sources constitutes a ...99 per cent complete sample of extragalactic sources brighter than S20GHz = 500 mJy at the selection epoch with declination ... < -30... The sample has a 91.4 per cent detection rate in polarization at ...20 GHz (94 per cent if considering the subsample of point-like sources). We have measurements also at 4.8 and 8.6 GHz within ~1 month of the 20 GHz observations for 172 sources to reconstruct the spectral properties of the sample in total intensity and in polarization: 143 of them have a polarization detection at all three frequencies. (ProQuest: ... denotes formulae/symbols omitted.)
The Radio/Optical Catalog of the SSA 13 Field Fomalont, E. B; Kellermann, K. I; Cowie, L. L ...
The Astrophysical journal. Supplement series,
12/2006, Letnik:
167, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present a 1.4 GHz catalog of 810 radio sources (560 sources in the complete sample) found in the SSA 13 field (R.A. = 13 super(h)12 super(m), decl. = 4238'). The 1.4 GHz radio image was obtained ...from a 91 hr VLA integration with an rms noise level of 4.82 kJy beam super(-1) at the field center. Optical images in the R band (6300 A) and z band (9200 A) with 3 s detection magnitudes of 26.1 and 24.9, respectively, were obtained from three observing nights on the 8 m Subaru Telescope. We find that 88% c 2% of the radio sources are identified with an optical counterpart. There is significantly more reddening for the optical counterparts that are fainter than 24 mag, probably caused by the somewhat larger redshifts of these faint galaxies. The radio and optical parameters are tabulated, and source morphologies are displayed by radio contours overlaid on optical false-color images. The brightness distributions show a wealth of complexity and are classified into a small number of categories. About one-third of the radio sources are larger than l."2, and their orientation is often similar to that of the associated galaxy or binary galaxy system. Radio emission is sometimes located outside of the nuclear regions of the galaxy. The density of sources in the SSA 13 field above 75 kJy is 0.40 arcmin super(-2), with a slope of -2.43 in the differential counts. This source density is somewhat higher than that in the Hubble Deep Field North. The radio spectral index may steepen for sources below 75 kJy and is consistent with the difference in the slope of the source counts observed between 1.4 and 8.4 GHz. We estimate that at most 40% of the microjansky radio sources are dominated by AGN processes, while the remainder are mostly the consequence of star formation and associated supernova activity.
To describe clinical features, morphology, management and outcome of pulmonary vein stenosis (PVS) in childhood.
Retrospective international collaborative study involving 19 paediatric cardiology ...centres in the UK, Ireland and Sweden.
Cases of PVS presenting between 1 January 1995 and 31 December 2004 were identified. Cases where pulmonary veins connected to a morphological left atrium were included. Functionally univentricular hearts and total anomalous pulmonary venous connection were excluded. All available data and imaging were reviewed.
58 cases were identified. In 22 cases (38%) there was premature delivery. 46 (79%) had associated cardiac lesions; 16 (28%) had undergone previous cardiac surgery before PVS diagnosis. 16 children (28%) had a syndrome or significant extracardiac abnormality. 36 presented with unilateral disease of which 86% was on the left. Where there was adequate sequential imaging, disease progression was shown with discrete stenosis leading to diffusely small pulmonary veins. Collateral vessels often developed. 13 patients had no intervention. Initial intervention was by catheter in 17 and surgery in 28. Overall 3-year survival was 49% (95% CI 35% to 63%) with patients undergoing initial surgical intervention having greater freedom from death or re-intervention (hazard ratio 0.44, 95% CI 0.2 to 0.99, p = 0.023).
PVS is a complex disease of uncertain cause and frequently associated with prematurity. Early intervention may be indicated to deter irreversible secondary changes.
Faint Radio Sources and Star Formation History Haarsma, D. B; Partridge, R. B; Windhorst, R. A ...
Astrophysical journal/The Astrophysical journal,
12/2000, Letnik:
544, Številka:
2
Journal Article
Abstract In order to explore short-term facilitation of the Schaffer collateral to CA1 synapse in mouse hippocampal brain slices, we measured the time course of the decay of the peak amplitude of ...successive EPSCs during progressive MK-801-dependent block (PMDB) of NMDAR responses to paired (R1 and R2) stimuli. We made the unexpected observation that the R2 response exhibited a slower PMDB decay constant than that of the R1 response. This indicated that the facilitated R2 response engages release sites with NMDARs that are protected from opening and consequent MK-801 block during the basal R1 response. We then utilized conditions that affect synaptic glutamate distribution to dissect the components of the distinct PMDB decay constants of the first and second of paired pulses. While extra-synaptic NMDARs and glutamate transporters appear to play only minor roles in the differences of the PMDB decay constant, we showed important roles for the R1 response itself and for glutamate diffusion in determining the PMDB decay constant of R2. We used a simple computational model with realistic parameters that allowed us to predict the time course of R2 decay based on the R1 decay time course.
We report on sensitive radio observations made with the VLA at 8.5 GHz centered on the Hubble Deep Field (HDF). We collected data in the A, CnB, C, DnC, and D configurations corresponding to angular ...resolutions ranging from 3 to 10 arcsec. We detected 29 radio sources in a complete sample within 46 of the HDF center and above a flux density limit of 9.0 micro-Jy. Seven of these sources are located within the HDF itself, while the remaining 22 sources are covered by the Hubble flanking fields or ground-based optical images. All of the sources in the HDF are identified with galaxies with a mean magnitude R = 21.7, while the mean magnitude of the identifications outside the HDF is R = 22.1. One radio source in the HDF, which is just below our formal completeness level but is confirmed by independent 1.4 GHz observations, has no optical counterpart above the HDF limit of R = 29. Three radio sources outside the HDF have no optical counterparts to R = 27. Based on a radio and optical positional coincidence, we detected an additional 19 radio sources in this field with S(v) not less than 6.3 micro-Jy and less than 9.0 micro-Jy and R = 25 or less but which are not included in the complete sample. The microjansky radio sources are distributed over a wide range of redshifts and have a typical monochromatic luminosity of about 10 exp 23 W/Hz. The majority of the optical identifications are with luminous galaxies at modest redshifts, many with evidence for recent star formation. (Author)
Most currently available counts of radio sources at frequencies >5 GHz are restricted to relatively bright sources. Observations made at NRAO's VLA have, however, provided counts of very faint ...sources (S < 1 mJy) at 8.5 GHz. Here we extend the 8.5 GHz VLA source counts to higher flux densities using both archival data and a brief, blind VLA survey at 8.5 GHz. We thus link the faint source counts to earlier source counts at S > 30 mJy. The new counts of radio sources at 8.5 GHz hold no surprises.
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