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Articles 1 - 6 of 6
Full-Text Articles in Physical Sciences and Mathematics
Comparing The Sfi Peculiar Velocities With The Pscz Gravity Field: A Velmod Analysis, E. Branchini, W. Freudling, L. N. Da Costa, C. S. Frenk, R. Giovanelli, M. P. Haynes, J. J. Salzer, G. Wegner, I. Zehavi
Comparing The Sfi Peculiar Velocities With The Pscz Gravity Field: A Velmod Analysis, E. Branchini, W. Freudling, L. N. Da Costa, C. S. Frenk, R. Giovanelli, M. P. Haynes, J. J. Salzer, G. Wegner, I. Zehavi
Dartmouth Scholarship
We compare the peculiar velocities derived from the I-band Tully–Fisher (TF) relation for 989 field spiral galaxies in the SFI catalogue with the predicted velocity field derived from the IRAS PSCz galaxy redshift survey. We assume linear gravitational instability theory and apply the maximum likelihood technique, VELMOD to SFI galaxies within a redshift cz LG =6000 km s−1. The resulting calibration of the TF relation is consistent with a previous, independent calibration for a similar sample of spirals residing in clusters. Our analysis provides an accurate estimate of the quantity βI ≡ Ωm0.6 …
Large-Scale Power Spectrum And Structures From The Enear Galaxy Peculiar Velocity Catalogue, S. Zaroubi, M. Bernardi, L. N. Da Costa, Y. Hoffman, M. V. Alonso, G. Wegner
Large-Scale Power Spectrum And Structures From The Enear Galaxy Peculiar Velocity Catalogue, S. Zaroubi, M. Bernardi, L. N. Da Costa, Y. Hoffman, M. V. Alonso, G. Wegner
Dartmouth Scholarship
We estimate the mass density fluctuations power spectrum (PS) on large scales by applying a maximum likelihood technique to the peculiar velocity data of the recently completed redshift—distance survey of early-type galaxies (hereafter ENEAR). Parametric cold dark matter (CDM)-like models for the PS are assumed, and the best-fitting parameters are determined by maximizing the probability of the model given the measured peculiar velocities of the galaxies, their distances and estimated errors. The method has been applied to CDM models with and without COBE normalization. The general results are in agreement with the high-amplitude power spectra found from similar analyses of …
Grb 010222: A Burst Within A Starburst, D. A. Frail, F. Bertoldi, G. H. Moriarty‐Schieven, E. Berger, P. A. Price, J. S. Bloom, R. Sari, S. R. Kulkarni, C. L. Gerardy, D. E. Reichart
Grb 010222: A Burst Within A Starburst, D. A. Frail, F. Bertoldi, G. H. Moriarty‐Schieven, E. Berger, P. A. Price, J. S. Bloom, R. Sari, S. R. Kulkarni, C. L. Gerardy, D. E. Reichart
Dartmouth Scholarship
We present millimeter and submillimeter wavelength observations and near-infrared K -band imaging toward the bright gamma-ray burst GRB 010222. Over seven epochs the flux density of the source was constant wit h an average flux density 3.74 ± 0.53 mJy at 350 GHz and 1.05 ± 0.22 mJy at 250 GHz, giving a spectral index α = 3 . 78 ± 0.25 (where F∝ να). We rule out the possibility that this emission originated from the burst or its afterglow and we conclu de that it is due to a dusty, high redshift starburst galaxy (SMM J14522+43 01). …
The Peculiar Motions Of Early-Type Galaxies In Two Distant Regions - Vi. The Maximum-Likelihood Gaussian Algorithm, M. Colless, R. P. Saglia, D. Burstein, R. L. Davies, R. K. Mcmahan, G. Wegner
The Peculiar Motions Of Early-Type Galaxies In Two Distant Regions - Vi. The Maximum-Likelihood Gaussian Algorithm, M. Colless, R. P. Saglia, D. Burstein, R. L. Davies, R. K. Mcmahan, G. Wegner
Dartmouth Scholarship
The EFAR project is designed to measure the properties and peculiar motions of early-type galaxies in two distant regions. Here we describe the maximum-likelihood algorithm we developed to investigate the correlations between the parameters of the EFAR data base. One-, two- and three-dimensional Gaussian models are constructed to determine the mean value and intrinsic spread of the parameters, and the slopes and intrinsic parallel and orthogonal spread of the Mg2–Mgb′,Mg2–σ,Mgb′–σ relations, and the Fundamental Plane. In the latter case, the cluster peculiar velocities are also determined. We show that this method is superior to …
The Peculiar Motions Of Early-Type Galaxies In Two Distant Regions -- Vii. Peculiar Velocities And Bulk Motions, Matthew Colless, R. P. Saglia, David Burstein, Roger L. Davies, Robert K. Mcmahan Jr, Gary Wegner
The Peculiar Motions Of Early-Type Galaxies In Two Distant Regions -- Vii. Peculiar Velocities And Bulk Motions, Matthew Colless, R. P. Saglia, David Burstein, Roger L. Davies, Robert K. Mcmahan Jr, Gary Wegner
Dartmouth Scholarship
We present peculiar velocities for 85 clusters of galaxies in two large volumes at distances between 6000 and 15 000 km s−1 in the directions of Hercules-Corona Borealis and Perseus-Pisces-Cetus (the EFAR sample). These velocities are based on Fundamental Plane (FP) distance estimates for early-type galaxies in each cluster. We fit the FP using a maximum likelihood algorithm which accounts for both selection effects and measurement errors, and yields FP parameters with smaller bias and variance than other fitting procedures. We obtain a best-fitting FP with coefficients consistent with the best existing determinations. We measure the bulk motions of …
Starbursts Versus Truncated Star Formation In Nearby Clusters Of Galaxies, James A. Rose, Alejandro E. E. Gaba, Nelson Caldwell, Brian Chaboyer
Starbursts Versus Truncated Star Formation In Nearby Clusters Of Galaxies, James A. Rose, Alejandro E. E. Gaba, Nelson Caldwell, Brian Chaboyer
Dartmouth Scholarship
We present long-slit spectroscopy, B - and R -bandpass imaging, and 21 cm observations of a sample of early-type galaxies in nearby clusters, which are known to be either in a star-forming phase or to have had star formation that recently terminated. From the long-slit spectra, obtained with the Blanco 4 m telescope, we ‹nd that emission lines in the star-forming cluster galaxies are signi‹cantly more centrally concentrated than in a sample of ‹eld galaxies. The broadband imaging reveals that two currently starforming early-type galaxies in the Pegasus I cluster have blue nuclei, again indicating that recent star formation has …