Cold and Calculating

This nonfiction essay investigates the relationship between eye contact and power in different situations. It brings up the idea that animals and humans are less different than often thought to be, and how body language is transcendent. It uses this underlying theme to investigate the author’s changing relationship with her father

The use of the wavelet cluster analysis for asteroid family determination

The asteroid family determination has been analysis method dependent for a longtime. A new cluster analysis based on the wavelet transform has allowed an automatic definition of families with a degree of significance versus randomness. Actually this method is rather general and can be applied to any kind of structural analysis. We will rather concentrate on the main features of the method. The analysis has been performed on the set of 4100 asteroid proper elements computed by Milani and Knezevic (see Milani and Knezevic 1990). Twenty one families have been found and influence of the chosen metric has been tested. The results have beem compared to Zappala et al.'s ones (see Zappala et al 1990) obtained by the use of a completely different method applied to the same set of data. For the first time, a good overlapping has been found between both method results, not only for the big well known families but also for the smallest ones

A catalogue of velocities in the cluster of galaxies Abell 85

We present a catalogue of velocities for 551 galaxies (and give the coordinates of 39 stars misclassified as galaxies in our photometric plate catalogue) in a region covering about 100'$\times$100' (0.94$\times$0.94 Mpc for an average redshift of 0.0555, assuming H$_\circ$=50 km s$^{-1}$ Mpc$^{-1}$) in the direction of the rich cluster Abell 85. This catalogue includes previously published redshifts by Beers et al. (1991) and Malumuth et al. (1992), together with our 367 new measurements. A total of 305 galaxies have velocities in the interval 13350-20000 km s$^{-1}$, and will be considered as members of the cluster. Abell 85 therefore becomes one of the clusters with the highest number of measured redshifts; its optical properties are being investigated in a companion paper.Comment: Accepted for publication in A&AS, Table 4 available in electronic form onl

A multiscale regularized restoration algorithm for XMM-Newton data

We introduce a new multiscale restoration algorithm for images with few photons counts and its use for denoising XMM data. We use a thresholding of the wavelet space so as to remove the noise contribution at each scale while preserving the multiscale information of the signal. Contrary to other algorithms the signal restoration process is the same whatever the signal to noise ratio is. Thresholds according to a Poisson noise process are indeed computed analytically at each scale thanks to the use of the unnormalized Haar wavelet transform. Promising preliminary results are obtained on X-ray data for Abell 2163 with the computation of a temperature map.Comment: To appear in the Proceedings of `Galaxy Clusters and the High Redshift Universe Observed in X-rays', XXIth Moriond Astrophysics Meeting (March 2001), Eds. Doris Neumann et a

Hydrogen-Air-Steam Combustion Regimes In Large Volumes

Dangerous pressure waves can be generated by the combustion of H2-air-steam mixtures if ordinary deflagrations accelerate to high speed or undergo deflagration-to-detonation transition (DDT). The purpose of this paper is to estimate the potentially dangerous mixtures in large volumes. There is a limited experimental data base for flame acceleration and DDT of EL-airsteam mixtures in smaller geometries. There is concern about the possible explosive combustion in the Space Shuttle main engine exhaust duct at Vandenberg AFB. There are no relevant experimental data or valid theories at this large scale (duct width, W, ~ 10 m) to predict flame acceleration and DDT. We have estimated potentially dangerous mixtures by extrapolating correlations used at smaller scale based on the detonation cell width, X. In square ducts DDTs are possible if W/X \u3e 1. We delineate three combustion regions: nonflammable, weakly flammable, and strongly flammable and potentially detonable. The nonflammable region is the region outside the flammability limit where self-sustaining combustion cannot occur. Flammability limits are independent of scale in large volumes. The strongly flammable region, where dangerous flame acceleration or DDT is possible, is bounded by mixtures with X = 10 m. We estimate detonations are possible when there is less than 45% steam. The weakly flammable region, which lies between the other two, should support only slow combustion, where no significant pressure waves should be generated

On the galaxy luminosity function in the central regions of the Coma cluster

We have obtained new redshifts for 265 objects in the central 48~$\times$~25~arcmin$^2$ region of the Coma cluster. When supplemented with literature data, our redshift sample is 95~\% complete up to a magnitude b$_{26.5}$=18.0 (the magnitudes are taken from the photometric sample of Godwin et al. 1983). Using redshift-confirmed membership for 205 galaxies, and the location in the colour-magnitude diagram for another 91 galaxies, we have built a sample of cluster members which is complete up to b$_{26.5}$=20.0. We show that the Coma cluster luminosity function cannot be adequately fitted by a single Schechter (1976) function, because of a dip in the magnitude distribution at b$_{26.5}$$\sim$17. The superposition of an Erlang (or a Gauss) and a Schechter function provides a significantly better fit. We compare the luminosity function of Coma to those of other clusters, and of the field. Luminosity functions for rich clusters look similar, with a maximum at $M_{b} \simeq -19.5 + 5 \times \log h_{50}$, while the Virgo and the field luminosity functions show a nearly monotonic behaviour. These differences may be produced by physical processes related to the environment which affect the luminosities of a certain class of cluster galaxies.Comment: 7 pages, uuencoded postscript file (figures included) Accepted for publication on A&

A photometric catalogue of galaxies in the cluster Abell 85

We present two catalogues of galaxies in the direction of the rich cluster \a85. The first one includes 4,232 galaxies located in a region $\pm 1^\circ$ from the cluster centre. It has been obtained from a list of more than 25,000 galaxy candidates detected by scanning a Schmidt photographic plate taken in the \bj band. Positions are very accurate in this catalogue but magnitudes are not. This led us to perform CCD imaging observations in the V and R bands to calibrate these photographic magnitudes. A second catalogue (805 galaxies) gives a list of galaxies with CCD magnitudes in the V and R bands for a much smaller region in the centre of the cluster. These two catalogues will be combined with a redshift catalogue of 509 galaxies (Durret et al. 1997; astro-ph/9709298) to investigate the cluster properties at optical wavelengths (Durret et al. in preparation), as a complement to our previous X-ray studies (Pislar et al. 1997, Lima-Neto et al. 1997).Comment: accepted for publication in A&AS; 7 pages, including 8 figures, Tables are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5

New Structure In The Shapley Supercluster

We present new radial velocities for 189 galaxies in a 91 sq. deg region of the Shapley supercluster measured with the FLAIR-II spectrograph on the UK Schmidt Telescope. The data reveal two sheets of galaxies linking the major concentrations of the supercluster. The supercluster is not flattened in Declination as was suggested previously and it may be at least 30 percent larger than previously thought with a correspondingly larger contribution to the motion of the Local Group.Comment: LaTex: 2 pages, 1 figure, includes conf_iap.sty style file. To appear in proceedings of The 14th IAP Colloquium: Wide Field Surveys in Cosmology, held in Paris, 1998 May 26--30, eds. S.Colombi, Y.Mellie