Metacarpophalangeal pattern profile analysis of a sample drawn from a North Wales population

This is tha author's PDF version of an article published in Annals of human biology© 2001. The definitive version is available at http://www.tandf.co.uk/journalsSexual dimorphism and population differences were investigated using metacarpophalangeal pattern profile (MCPP) analysis. Although it is an anthropmetric technique, MCPP analysis is more frequently used in genetic syndrome analysis and has been under-used in the study of human groups. The present analysis used a series of hand radiographics from Gwynedd, North Wales, to make comparisons, first, between the sexes within the sample and then with previously reported data from Japan. The Welsh sexes showed MCPP analyses that indicated size and shape differences but certain similarities in shape were also evident. Differences with the Japanese data were more marked. MCPP anlysis is a potentially useful anthropmetric technique but requires further statistical development

Supernovae in Low-Redshift Galaxy Clusters: Observations by the Wise Observatory Optical Transient Search (WOOTS)

We describe the Wise Observatory Optical Transient Search (WOOTS), a survey for supernovae (SNe) and other variable and transient objects in the fields of redshift 0.06-0.2 Abell galaxy clusters. We present the survey design and data-analysis procedures, and our object detection and follow-up strategies. We have obtained follow-up spectroscopy for all viable SN candidates, and present the resulting SN sample here. Out of the 12 SNe we have discovered, seven are associated with our target clusters while five are foreground or background field events. All but one of the SNe (a foreground field event) are Type Ia SNe. Our non-cluster SN sample is uniquely complete, since all SN candidates have been either spectroscopically confirmed or ruled out. This allows us to estimate that flux-limited surveys similar to WOOTS would be dominated (~80%) by SNe Ia. Our spectroscopic follow-up observations also elucidate the difficulty in distinguishing active galactic nuclei from SNe. In separate papers we use the WOOTS sample to derive the SN rate in clusters for this redshift range, and to measure the fraction of intergalactic cluster SNe. We also briefly report here on some quasars and asteroids discovered by WOOTS.Comment: Submitted to ApJ. Comments welcom

Morphological aspects of male and female hands

This is an electronic version of an article published in Annals of Human Biology, 1996, 23(6), 491-494. Annals of Human Biology is available online at informaworldTM http://www.informaworld.com/smpp/content~content=a739339013~db=all~order=pageThis journal article discusses a series of hand radiographs from Gwynedd, North Wales, which were assessed for frequencies in digital and metacarpal formulae between the genders

On the fraction of intermediate-mass close binaries that explode as type-Ia supernovae

Type-Ia supernovae (SNe-Ia) are thought to result from a thermonuclear runaway in white dwarfs (WDs) that approach the Chandrasekhar limit, either through accretion from a companion or a merger with another WD. I compile observational estimates of the fraction eta of intermediate-mass stars that eventually explode as SNe-Ia, supplement them with several new estimates, and compare them self-consistently. The estimates are based on five different methods, each utilising some observable related to the SN-Ia rate, combined with assumptions regarding the IMF: the ratio of SN-Ia to core-collapse rates in star-forming galaxies; the SN-Ia rate per unit star-formation rate; the SN-Ia rate per unit stellar mass; the iron to stellar mass ratio in galaxy clusters; and the abundance ratios in galaxy clusters. The five methods indicate that a fraction in the range eta~2-40% of all stars with initial masses of 3-8 M_sun (the generally assumed SN-Ia progenitors) explode as SNe-Ia. A fraction of eta~15% is consistent with all five methods for a range of plausible IMFs. Considering also the binarity fraction among such stars, the mass ratio distribution, the separation distribution, and duplicity (every binary can produce only one SN-Ia explosion), this implies that nearly every intermediate mass close binary ends up as a SN-Ia, or possibly more SNe-Ia than progenitor systems. Theoretically expected fractions are generally one to two orders of magnitude lower. The problem could be solved: if all the observational estimates are in error; or with a ``middle-heavy'' IMF; or by some mechanism that strongly enhances the efficiency of binary evolution toward SN-Ia explosion; or by a non-binary origin for SNe-Ia.Comment: MNRAS, accepted versio

A New Determination of the High Redshift Type Ia Supernova Rates with the Hubble Space Telescope Advanced Camera for Surveys

We present a new measurement of the volumetric rate of Type Ia supernova up to a redshift of 1.7, using the Hubble Space Telescope (HST) GOODS data combined with an additional HST dataset covering the North GOODS field collected in 2004. We employ a novel technique that does not require spectroscopic data for identifying Type Ia supernovae (although spectroscopic measurements of redshifts are used for over half the sample); instead we employ a Bayesian approach using only photometric data to calculate the probability that an object is a Type Ia supernova. This Bayesian technique can easily be modified to incorporate improved priors on supernova properties, and it is well-suited for future high-statistics supernovae searches in which spectroscopic follow up of all candidates will be impractical. Here, the method is validated on both ground- and space-based supernova data having some spectroscopic follow up. We combine our volumetric rate measurements with low redshift supernova data, and fit to a number of possible models for the evolution of the Type Ia supernova rate as a function of redshift. The data do not distinguish between a flat rate at redshift > 0.5 and a previously proposed model, in which the Type Ia rate peaks at redshift >1 due to a significant delay from star-formation to the supernova explosion. Except for the highest redshifts, where the signal to noise ratio is generally too low to apply this technique, this approach yields smaller or comparable uncertainties than previous work.Comment: Accepted for publication in Ap

Evidence for a Compact Wolf-Rayet Progenitor for the Type Ic Supernova PTF 10vgv

We present the discovery of PTF 10vgv, a Type Ic supernova (SN) detected by the Palomar Transient Factory, using the Palomar 48 inch telescope (P48). R-band observations of the PTF 10vgv field with P48 probe the SN emission from its very early phases (about two weeks before R-band maximum) and set limits on its flux in the week prior to the discovery. Our sensitive upper limits and early detections constrain the post-shock-breakout luminosity of this event. Via comparison to numerical (analytical) models, we derive an upper-limit of R ≾ 4.5 R_☉ (R ≾ 1 R_☉) on the radius of the progenitor star, a direct indication in favor of a compact Wolf-Rayet star. Applying a similar analysis to the historical observations of SN 1994I yields R ≾ 1/4 R_☉ for the progenitor radius of this SN

The detailed optical light curve of GRB 030329

(Abridged) We present densely sampled BVRI light curves of the optical transient associated with the gamma-ray burst GRB 030329, the result of a coordinated observing campaign conducted at five observatories. Augmented with published observations of this GRB, the compiled optical dataset contains 2687 photometric measurements, obtained between 78 minutes and 79 days after the burst. We show that the underlying supernova 2003dh evolved faster than, and was probably somewhat fainter than the type Ic SN 1998bw, associated with GRB 980425. We find that our data can be described by a broken power-law decay perturbed by a complex variable component. The early- and late-time decay slopes are determined to be ~1.1 and ~2, respectively. Assuming this single power-law model, we constrain the break to lie between ~3 and ~8 days after the burst. This simple, singly-broken power-law model, derived only from the analysis of our optical observations, may also account for available multi-band data, provided that the break happened ~8 days after the burst. The more complex double-jet model of Berger et al. provides a comparable fit to the optical, X-ray, mm and radio observations of this event. We detect a significant change in optical colors during the first day. Our color analysis is consistent with a cooling break frequency sweeping through the optical band during the first day. The light curves of GRB 030329 reveal a rich array of variations, superposed over the mean power-law decay. We find that the early variations are asymmetric, with a steep rise followed by a relatively slower (by a factor of about two) decline. The variations maintain a similar time scale during the first four days, and then get significantly longer.Comment: 14 pages, 12 figures, accepted for publication in ApJ with minor changes. See the GRB030329 Data Treasury at http://wise-obs.tau.ac.il/GRB030329

Near-IR Search for Lensed Supernovae Behind Galaxy Clusters - II. First Detection and Future Prospects

Powerful gravitational telescopes in the form of massive galaxy clusters can be used to enhance the light collecting power over a limited field of view by about an order of magnitude in flux. This effect is exploited here to increase the depth of a survey for lensed supernovae at near-IR wavelengths. A pilot SN search program conducted with the ISAAC camera at VLT is presented. Lensed galaxies behind the massive clusters A1689, A1835 and AC114 were observed for a total of 20 hours split into 2, 3 and 4 epochs respectively, separated by approximately one month to a limiting magnitude J<24 (Vega). Image subtractions including another 20 hours worth of archival ISAAC/VLT data were used to search for transients with lightcurve properties consistent with redshifted supernovae, both in the new and reference data. The feasibility of finding lensed supernovae in our survey was investigated using synthetic lightcurves of supernovae and several models of the volumetric Type Ia and core-collapse supernova rates as a function of redshift. We also estimate the number of supernova discoveries expected from the inferred star formation rate in the observed galaxies. The methods consistently predict a Poisson mean value for the expected number of SNe in the survey between N_SN=0.8 and 1.6 for all supernova types, evenly distributed between core collapse and Type Ia SN. One transient object was found behind A1689, 0.5" from a galaxy with photometric redshift z_gal=0.6 +- 0.15. The lightcurve and colors of the transient are consistent with being a reddened Type IIP SN at z_SN=0.59. The lensing model predicts 1.4 magnitudes of magnification at the location of the transient, without which this object would not have been detected in the near-IR ground based search described in this paper (unlensed magnitude J~25). (abridged)Comment: Accepted by AA, matches journal versio