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Complete Sample (complete + sample)
Selected AbstractsModelling current trends in Northern Hemisphere temperaturesINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 7 2006Terence C. Mills Abstract Fitting a trend is of interest in many disciplines, but it is of particular importance in climatology, where estimating the current and recent trend in temperature is thought to provide a major indication of the presence of global warming. A range of ad hoc methods of trend fitting have been proposed, with little consensus as to the most appropriate techniques to use. The aim of this paper is to consider a range of trend extraction techniques, none of which require ,padding' out the series beyond the end of the available observations, and to use these to estimate the trend of annual mean Northern Hemisphere (NH) temperatures. A comparison of the trends estimated by these methods thus provides a robust indication of the likely range of current trend temperature increases and hence inform, in a timely quantitative fashion, arguments based on global temperature data concerning the nature and extent of global warming and climate change. For the complete sample 1856,2003, the trend is characterised as having long waves about an underlying increasing level. Since around 1970, all techniques display a pronounced warming trend. However, they also provide a range of trend functions so that extrapolation far into the future would be a hazardous exercise. Copyright © 2006 Royal Meteorological Society. [source] The ionization of the emission-line gas in young radio galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2009J. Holt ABSTRACT This paper is the second in a series in which we present intermediate-resolution, wide-wavelength coverage spectra for a complete sample of 14 compact radio sources, taken with the aim of investigating the impact of the nuclear activity on the circumnuclear interstellar medium (ISM) in the early stages of radio source evolution. In the first paper (Holt, Tadhunter & Morganti), we presented the kinematic results from the nuclear emission-line modelling and reported fast outflows in the circumnuclear gas. In this paper, we use the line fluxes to investigate the physical conditions and dominant ionization mechanisms of the emission-line gas. We find evidence for large electron densities and high reddening in the nuclear regions, particularly in the broader, blueshifted components. These results are consistent with the idea that the young, recently triggered radio sources still reside in dense and dusty cocoons deposited by the recent activity triggering event (merger/interaction). In addition, we find that the quiescent nuclear and extended narrow components are consistent with active galactic nucleus (AGN) photoionization, split between simple-slab AGN photoionization and mixed-medium photoionization models. For the nuclear broader and shifted components, the results are less clear. Whilst there are suggestions that the broader components may be closer to shock plus precursor models on the diagnostic diagrams, and that the electron temperatures and densities are high, we are unable to unambiguously distinguish the dominant ionization mechanism using the optical emission-line ratios. This is surprising given the strong evidence for jet,cloud interactions (broad emission lines, large outflow velocities and strong radio-optical alignments), which favours the idea that the warm gas has been accelerated in shocks driven by the radio lobes expanding through a dense cocoon of gas deposited during the triggering event. [source] A sample of mJy radio sources at 1.4 GHz in the Lynx and Hercules fields , I. Radio imaging, multicolour photometry and spectroscopyMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007E. E. Rigby ABSTRACT With the goal of identifying high-redshift radio galaxies with Fanaroff,Riley class I (FR I) classification, here are presented high-resolution, wide-field radio observations, near-infrared and optical imaging and multi-object spectroscopy of two fields of the Leiden,Berkeley Deep Survey. These fields, Hercules.1 and Lynx.2, contain a complete sample of 81 radio sources with S1.4 GHz > 0.5 mJy within 0.6 deg2. This sample will form the basis for a study of the population and cosmic evolution of high-redshift, low-power, FR I radio sources which will be presented in Paper II. Currently, the host galaxy identification fraction is 86 per cent with 11 sources remaining unidentified at a level of r,, 25.2 mag (Hercules; four sources) or r,, 24.4 mag (Lynx; seven sources) or K, 20 mag. Spectroscopic redshifts have been determined for 49 per cent of the sample and photometric redshift estimates are presented for the remainder of the sample. [source] The cluster environments of radio-loud quasars at 0.6 < z < 1.1MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2003J. M. Barr ABSTRACT We have carried out multicolour imaging of a complete sample of radio-loud quasars at 0.6 < z < 1.1 and find groups or clusters of galaxies in the fields of at least eight and possibly 13 of the 21 sources. There is no evidence for an evolution in the richness of the environments of radio-loud quasars from other low-redshift studies to z, 0.9. The quasars associated with groups and clusters in our sample do not necessarily reside in the centre of the galaxy distribution, which rarely displays a spherical geometry. Clustering is preferentially associated with small or asymmetric steep-spectrum radio sources. The quasars with the largest projected angular size are, in nearly all cases, found in non-clustered environments. Radio-based selection (including source size) of high-redshift groups and clusters can be a very efficient method of detecting rich environments at these redshifts. We find that in optical searches for galaxy overdensities above z, 0.6, multiple filters must be used. If the single-filter counting statistics used by groups at lower redshift are applied to our data, uncertainties are too large to make accurate quantifications of cluster richness. This means that genuine clustering of galaxies about quasars will be missed and, in ,10 per cent of cases, putative clusters turn out to be false detections. The statistics are further diluted by the fact that galaxy overdensities are generally not centred on the quasar. [source] The relative abundances of ellipticals and starbursts among the extremely red galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2002F. Mannucci We present J -band observations of a complete sample of 57 red galaxies selected to have and . We use a prescription based on the and colours, to separate the two dominant populations, old ellipticals and dusty starbursts. We find that both populations are present in the current sample and have similar abundances, and discuss the uncertainties in this result. Galactic stars comprise about 9 per cent of the objects. The starburst galaxies of the present sample are found to give a contribution to the cosmic star formation density similar to the Lyman-break galaxies. [source] Broad-band colours of Virgo cluster low surface brightness dwarf irregular galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2001Ana B. Heller We present UBVRI images and surface photometry of a complete sample of 29 low-luminosity dwarf irregular galaxies in the Virgo cluster, for which we derive central surface brightnesses, scalelengths, integrated magnitudes and median colours. The colour distributions are discussed in terms of radial surface brightness profiles, and colour gradients are interpreted and compared with corresponding ones for low surface-brightness (LSB) spiral galaxies. By combining broad-band and narrow-band filter observations, the past and current influences of the cluster environment on the evolution of LSB dwarf irregular galaxies is evaluated. [source] The constant-density region of the dark haloes of spiral galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2001Paolo Salucci We determine a crucial feature of the dark halo density distribution from the fact that the luminous matter dominates the gravitational potential at about one disc scalelength Rd, but at the optical edge the dark matter has already become the main component of the galaxy density. From the kinematics of 137 spirals we find that the dark matter halo density profiles are self-similar at least out to Ropt and show core radii much larger than the corresponding disc scalelengths. The luminous regions of spirals consist of stellar discs embedded in dark haloes with roughly constant density. This invariant dark matter profile is very difficult to reconcile with the fundamental properties of the density distribution of cold dark matter haloes. With respect to previous work, the present evidence is obtained by means of a robust method and for a large and complete sample of normal spirals. [source] A weak lensing estimate from GEMS of the virial to stellar mass ratio in massive galaxies to z, 0.8MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2006Catherine Heymans ABSTRACT We present constraints on the evolution of the virial to stellar mass ratio of galaxies with high stellar masses in the redshift range 0.2 < z < 0.8, by comparing weak lensing measurements of virial mass Mvir with estimates of stellar mass Mstar. For a complete sample of galaxies with log (Mstar/M,) > 10.5, where the majority show an early-type morphology, we find that the virial mass to stellar mass ratio is given by Mvir/Mstar= 53+13,16. Assuming a baryon fraction from the concordance cosmology, this corresponds to a stellar fraction of baryons in massive galaxies of ,*b/,b= 0.10 ± 0.03. Analysing the galaxy sample in different redshift slices, we find little or no evolution in the virial to stellar mass ratio, and place an upper limit of ,2.5 on the growth of massive galaxies through the conversion of gas into stars from z= 0.8 to the present day. [source] Soft gamma-ray repeater giant flares in the BATSE short gamma-ray burst catalogue: constraints from spectroscopyMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2005Davide Lazzati ABSTRACT The giant flare observed on 2004 December 27 from SGR 1806,20 has revived the idea that a fraction of short (<2 s) gamma-ray bursts (GRBs) are due to giant flares from soft gamma-ray repeaters (SGRs) located in nearby galaxies. One of the distinguishing characteristics of these events is the thermal (blackbody) spectrum with temperatures ranging from ,50 to ,180 keV, with the highest temperature observed for the initial 0.2-s spike of the 2004 December 27 event. We have analysed the spectra of a complete sample of short GRBs with peak fluxes greater than 4 photon s,1 cm,2 detected by BATSE. Of the 115 short GRBs so selected, only 76 had sufficient signal-to-noise ratio to allow the spectral analysis. We find only three short GRBs with a spectrum well fitted by a blackbody, with 60 ,kT, 90 keV, albeit with a considerably longer duration (i.e. ,1 s) and a more complex light curve than the 2004 December 27 event. This implies a stringent limit on the rate of extragalactic SGR giant flares with spectral properties analogous to the December 27 flare. We conclude that up to 4 per cent of the short GRBs could be associated with giant flares (2, confidence). This implies that either the distance to SGR 1806,20 is smaller than 15 kpc or the rate of Galactic giant flares is lower than the estimated 0.033 yr,1. [source] Frequencies of hydrophobic and hydrophilic runs and alternations in proteins of known structurePROTEIN SCIENCE, Issue 1 2006Russell Schwartz Abstract Patterns of alternation of hydrophobic and polar residues are a profound aspect of amino acid sequences, but a feature not easily interpreted for soluble proteins. Here we report statistics of hydrophobicity patterns in proteins of known structure in a current protein database as compared with results from earlier, more limited structure sets. Previous studies indicated that long hydrophobic runs, common in membrane proteins, are underrepresented in soluble proteins. Long runs of hydrophobic residues remain significantly underrepresented in soluble proteins, with none longer than 16 residues observed. These long runs most commonly occur as buried , helices, with extended hydrophobic strands less common. Avoiding aggregation of partially folded intermediates during intracellular folding remains a viable explanation for the rarity of long hydrophobic runs in soluble proteins. Comparison between database editions reveals robustness of statistics on aqueous proteins despite an approximately twofold increase in nonredundant sequences. The expanded database does now allow us to explain several deviations of hydrophobicity statistics from models of random sequence in terms of requirements of specific secondary structure elements. Comparison to prior membrane-bound protein sequences, however, shows significant qualitative changes, with the average hydrophobicity and frequency of long runs of hydrophobic residues noticeably increasing between the database editions. These results suggest that the aqueous proteins of solved structure may represent an essentially complete sample of the universe of aqueous sequences, while the membrane proteins of known structure are not yet representative of the universe of membrane-associated proteins, even by relatively simple measures of hydrophobic patterns. [source] High frequency GPS sources in the AT20G surveyASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009P.J. Hancock Abstract The Australia Telescope 20 GHz (AT20G) survey was used to select a complete sample of 656 Gigahertz Peaked Spectrum (GPS) sources with spectral turnovers above 5 GHz. The AT20G has near simultaneous observations at 4.8, 8.6 and 20 GHz, which makes it possible to exclude flat spectrum variability as a cause of a source's peaked spectrum. Optical identification of the sample results in 361 QSOs and 104 galaxies and 191 blank fields. Redshifts are known for 104 of the GPS sources. The GPS sources from the AT20G are discussed and compared to previously known samples. The new sample of high frequency peaking GPS sources is found at a lower redshift than previous samples and to also have a lower 5 GHz radio power. Evidence is found to support the idea that the origin of the GPS spectral shape are intrinsically different for galaxies and QSOs. This paper is an elaboration and extension of the talk given at the 4th CSS/GPS conference in Riccione in May this year (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A complete sample of low polarization CSO/MSOASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009P. Cassaro Abstract The selection of a complete sample of Compact Symmetric Objects (CSOs) is in progress. The sample of candidates has been obtained on the basis of the low fractional polarization of the CSOs. About 60 % of the candidates has been identified as CSO/MSO, and observations are in progress to determine the radio morphology of the sources with unknown structure (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The building blocks of young AGNs: A progress report on follow-up projects with the CORALZ sampleASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009K.-H. Mack Abstract This paper summarizes some of the ongoing projects on the CORALZ sample, the first statistically complete sample of young radio galaxies. The low redshift of the sources in the sample (z < 0.16) makes them excellent targets for a comprehensive and homogeneous follow-up in virtually all bands of the electromagnetic spectrum. Here we report on the almost completed radio continuum observations which confirm the relatively young ages of the sources in the CORALZ sample. The radio spectra in addition with new measurements at 250 GHz indicate a large fraction of sources with excess mm-emission, probably due to radiation of cold dust. These sources are also excellent candidates for detection ofmolecular gas, which we have traced through CO observations in the 3-mm band in several cases. Additional molecules as H2O or OH are being observed. The atomic gas content is disclosed by H I absorption observations (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||