3,895 research outputs found
The hierarchical build-up of the Tully-Fisher relation
No full textWe use the semi-analytic model GalICS to predict the Tully-Fisher relation in the B, I and for the first time, in the K band, and its evolution with redshift, up to z~1. We refined the determination of the disk galaxies rotation velocity, with a dynamical recipe for the rotation curve, rather than a simple conversion from the total mass to maximum velocity. The new recipe takes into account the disk shape factor, and the angular momentum transfer occurring during secular evolution leading to the formation of bulges. This produces model rotation velocities that are lower by ~20-25% for the majority of the spirals. We implemented stellar population models with a complete treatment of the TP-AGB, which leads to a revision of the mass-to-light ratio in the near-IR. I/K band luminosities increase by ~0.3/0.5 mags at redshift z=0 and by ~0.5/1 mags at z=3. With these two new recipes in place, the comparison between the predicted Tully-Fisher relation with a series of datasets in the optical and near-IR, at redshifts between 0 and 1, is used as a diagnostics of the assembly and evolution of spiral galaxies in the model. At 0.
Pre-clearing vegetation of the coastal lowlands of the Wet Tropics Bioregion, North Queensland
No full textA pre-clearing vegetation map and digital coverage at approximately 1:50 000 scale for the coastal lowlands (up to about 200 m elevation) of the Wet Tropics Bioregion, North Queensland is presented. The study area covers about 508 000 ha from Cooktown, 420 km south almost to Townsville (latitude 15° 30’–18° 20’ longitude 144° 50’–146° 40’). Data sources included historical aerial photography, early surveyors’ plans, explorers’ journals, previous vegetation maps, and maps of soils and geology. The pre-clearing mapping was built around the remnant vegetation mapping of Stanton & Stanton (2005), and the vegetation classification of this latter work was adopted. Vegetation units were further classified into regional ecosystems compatible with the standard State-wide system used by Queensland government. The digital coverage is part of the current Queensland Herbarium regional ecosystem coverage (Queensland Herbarium and Wet Tropics Management Authority 2005). Coloured maps (1:100 000 scale) of the pre-clearing vegetation of the Herbert, Tully, Innisfail and Macalister/Daintree subregions are on an accompanying CD-ROM. An evaluation of vegetation loss through clearing on the coastal lowlands of the Wet Tropics revealed several nearextinct vegetation communities and regional ecosystems, and many others that are drastically reduced in area. Even ecosystems occurring on poorly drained lands have suffered a surprisingly high level of loss due to the effectiveness of drainage operations. Grassland ecosystems were found to be widespread on the Herbert and Tully floodplains, but are now close to extinction. The lowlands vegetation of the Wet Tropics that remains today continues to be fragmented and degraded despite the introduction of State-wide broad-scale tree-clearing laws in 1999, and the cessation of broadscale tree-clearing in December 2006
A New Kind of Europe? Democratic Integration in the European Union
No full textThe most urgent problem facing the European Union is to develop the best approach to conflicts over integration in the fields of culture, economics and foreign policy. The paper argues that a particular form of democratic integration is better than the two predominant approaches. This approach draws on the actual practices of the democratic negotiation of integration that citizens engage in on a daily basis but which tend to be overlooked and overridden in the dominant approaches.economics; democracy; law; diversity/homogeneity
Understanding carnivore killing behaviour: Exploring the motivations for tiger killing in the Sundarbans, Bangladesh
No full textThis paper explores village-based tiger killing (TK) among communities bordering the Sundarbans mangrove forest, Bangladesh. We find that TKs are not purely retaliatory in nature (i.e. a desire for retribution following livestock depredation or attacks on humans by tigers) and that previous negative experience of tigers is not the sole determinant of villagers’ acceptance of TK behaviour. Inter-related social-psychological factors (risk perceptions, beliefs about tigers, tolerance for tigers), institutional failings (i.e. of the institutions villagers perceive to be responsible for resolving village tiger incidents), perceived personal rewards (financial rewards, enhanced social status, medicinal or protective value of tiger body parts), and contextual factors (the severity of a village tiger incident) motivate people to kill tigers when they enter villages and foster the widespread acceptance of this behaviour. Knowledge of these motivational factors can be used to develop conservation actions suitable for developing both communities’ capacity and, crucially, desire to co-exist with tigers and to respond with non-lethal action to village tiger incidents
The tully-fisher relation in nearby clusters
No full textIn this thesis are presented the Tully-fisher (TF) relations for a sample of 99 galaxies within the four nearby dusters; Coma, Abell 2199. Abell 2634 and Abell 194. Each cluster was compromised of two samples. The first sample was drawn from either Zwicky or UGC catalogues based on a combination of magnitude, type and ellipticity. These provided spiral duster member candidates over the entire duster region to a magnitude limit of 16 in the b-band. The second sample was selected from published photographic plate scans of the central areas of each duster. This sample had a fainter magnitude limit of 18 b-band mags but covered a much smaller area (approx. 2ºx2º). The galaxies were observed over two observing runs in May and August of 1993 on the JKT and INT Isaac Newton Group Telescopes simultaneously. I-band CCD images and optical long-slit spectra were taken of 65% of the sdected objects. Isophotal ellipse fitting of the images was used to produce surface brightness profiles. From these, isophotal magnitudes and diameters woe extracted. From, consideration of the surface brightness, ellipticity and position angle a "disk region" of each profile was selected and used to calculate extrapolated total magnitudes. Gaussian fitting of Ha emission lines of the long-split spectra produced optical rotation curves for each galaxy. Maximum rotation velocities were calculated from these curves. Corrections found in the literature were applied to the total magnitude and rotation velocity of each galaxy. These compensated for internal dust extinction and the inclination of the disk to the line-of sight. Numerical simulations of the fitting procedures demonstrated that an inverse regression of log-rotation velocity on magnitude provided a fit tothe relationship free from selection bias. Residuals around this fit woe used to choose forms of the corrections that produced the minimum scatter. A fullerror budget was compiled and an error weighted fit to the data yielded relationships with a mean scatter of 0.35 mags rms. A combination of all sources of measurement error, considering inter-correlation, produced a value of 027 mags rms, as an estimate of the contribution to the scatter. It was shown that uncertain cluster membership was not a significant source of scatter. In addition, the "expanding duster" model correction suggested in the literature did not significantly reduce the scatter. The most important source of scatter in the relationship was found to be the symmetry and extent of rotation curves used. A significant correlation was shown to exist between rotation curve extent in terms of disk scale lengths and the TF fit residuals. When only the highest quality data were used, the typical scatter was reduced to 020 mags rms. Consideration of the remaining measurement errors produced an upper limit of 0.12 mags rms for the intrinsic scatter within the TF relation. Monte-Carlo modelling indicated that the observed difference in TF slope between the Coma and Abell 2634 samples was significant, The possibility that this difference is the result of systematic errors in the dataset was ruled out It is concluded that the change in gradients is due to real variations in the underlying slope influenced by differences in duster environment
Mrs. Tully J. Petty Junior, Mrs. Julian Read, Mrs. T. G. McAllister, Mrs. J. Roby Penn Junior, and Mrs. Jack Elliston, at the Fort Worth Art Association
No full textMrs. Tully J. Petty Junior (in foreground), chairman of special entertainment with (left to right) Mrs. Julian Read, publicity co-chairman; Mrs. T. G. McAllister, telephone; Mrs. J. Roby Penn Junior, refreshments; and Mrs. Jack Elliston, who with Mrs. C. Dickie Williamson, is general co-chairman of the art ball committee. The women are photographed with a board with various photos that will be displayed in the bazar section of the fiesta. Fort Worth Star-Telegram Morning edition April 29, 1962.https://mavmatrix.uta.edu/specialcollections_startelegram1960s/1788/thumbnail.jp
Revisiting the optical depth of spiral galaxies using the Tully-Fisher B relation
No full textInternational audienceAims. We attempt to determine the optical depth of spiral galaxy disks by a statistical study of new Tully-Fisher data from the ongoing KLUN+survey, and to clarify the difference between the true and apparent behavior of optical depth.Methods. By utilizing so-called normalized distances, a subsample of the data is identified to be as free from selection effects as possible. For these galaxies, a set of apparent quantities are calculated for face-on positions using the Tully-Fisher diameter and magnitude relations. These values are compared with direct observations to determine the mean value of the parameter C describing the optical depth.Results. The present study suggests that spiral galaxy disks are relatively optically thin tau(B) approximate to 0.1, at least in the outermost regions, while they appear in general to be optically thick tau(B) > 1 when the apparent magnitude and average surface brightness are studied statistically
The Baryonic Tully-Fisher Relationship for SG Galaxies and the "Condensed" Baryon Fraction of Galaxies
No full textaccepted for publication in AJWe combine data from the Spitzer Survey for Stellar Structure in Galaxies (SG), a recently calibrated empirical stellar mass estimator from Eskew et al., and an extensive database of HI spectral line profiles to examine the baryonic Tully-Fisher (BTF) relation. We find 1) that the BTF has lower scatter than the classic Tully-Fisher (TF) relation and is better described as a linear relationship, confirming similar previous results, 2) that the inclusion of a radial scale in the BTF decreases the scatter but only modestly, as seen previously for the TF relation, and 3) that the slope of the BTF, which we find to be ( log log ), implies that on average a nearly constant fraction () of all baryons expected to be in a halo are "condensed" onto the central region of rotationally supported galaxies. The condensed baryon fraction, , is, to our measurement precision, nearly independent of galaxy circular velocity (our sample spans circular velocities, , between 60 and 250 km s, but is extended to km s using data from the literature). The observed galaxy-to-galaxy scatter in this fraction is generally a factor of 2 despite fairly liberal selection criteria. These results imply that cooling and heating processes, such as cold vs. hot accretion, mass loss due to stellar winds, and AGN driven feedback, to the degree that they affect the global galactic properties involved in the BTF, are independent of halo mass for galaxies with km/s and typically introduce no more than a factor of two range in the resulting . Recent simulations by Aumer et al. of a small sample of disk galaxies are in excellent agreement with our data, suggesting that current simulations are capable of reproducing the global properties of individual disk galaxies
New perspectives on segmented crystal calorimeters for future colliders
No full textCrystal calorimeters have a long history of pushing the frontier on high-resolution electromagnetic (EM) calorimetry for photons and electrons. We explore in this paper major innovations in collider detector performance that can be achieved with crystal calorimetry when longitudinal segmentation and dual-readout capabilities are combined with a new high EM resolution approach to Particle Flow in multi-jet events, such as e+e+→ HZ events in all-hadronic final-states at Higgs factories. We demonstrate a new technique for pre-processing π0 momenta through combinatoric di-photon pairing in advance of applying jet algorithms. This procedure significantly reduces π0 photon splitting across jets in multi-jet events. The correct photon-to-jet assignment efficiency improves by a factor of about 3 when the EM resolution is improved from 15 to 3%/√E. In addition, the technique of bremsstrahlung photon recovery significantly improves electron momentum measurements. A high EM resolution calorimeter increases the Z boson recoil mass resolution in Higgstrahlung events for decays into electron pairs to 80% of that for muon pairs. We present the design and optimization of a highly segmented crystal detector concept that achieves the required energy resolution of 3%/√E, and a time resolution better than 30 ps providing exceptional particle identification capabilities. We demonstrate that, contrary to previous detector designs that suffered from large neutral hadron resolution degradation from one interaction length of crystals in front of a sampling hadron calorimeter, the implementation of dual-readout on crystals permits to achieve a resolution better than 30%/√E⊕ 2% for neutral hadrons. Our studies find that the integration of crystal calorimetry into future Higgs factory collider detectors can open new perspectives by yielding the highest level of combined EM and neutral hadron resolution in the PFA paradigm
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