15,853 research outputs found

    The Possible z=0.83 Precursors of z=0 M* Early-type Cluster Galaxies

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    We examine the distribution of stellar masses of galaxies in MS 1054-03 and RX J0152.7-1357, two X-ray selected clusters of galaxies at z=0.83. Our stellar mass estimates, from spectral energy distribution fitting, reproduce the dynamical masses as measured from velocity dispersions and half-light radii with a scatter of 0.2 dex in the mass for early-type galaxies. When we restrict our sample of members to high stellar masses, > 1e11.1 Msun (M* in the Schechter mass function for cluster galaxies), we find that the fraction of early-type galaxies is 79 +/- 6% at z=0.83 and 87 +/- 6% at z=0.023 for the Coma cluster, consistent with no evolution. Previous work with luminosity-selected samples finds that the early-type fraction in rich clusters declines from =~80% at z=0 to =~60% at z=0.8. The observed evolution in the early-type fraction from luminosity-selected samples must predominately occur among sub-M* galaxies. As M* for field and group galaxies, especially late-types, is below M* for clusters galaxies, infall could explain most of the recent early-type fraction growth. Future surveys could determine the morphological distributions of lower mass systems which will confirm or refute this explanation.Comment: 5 pages in emulate ApJ format with three color figures. Accepted for publication in ApJ Letters, v642n2. Updated to correct grammatical and typographic errors found by the journa

    Mass-Selection and the Evolution of the Morphology-Density Relation from z=0.8 to z=0

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    We examined the morphology-density relations for galaxy samples selected by luminosity and by mass in each of five massive X-ray clusters from z=0.023 to 0.83 for 674 spectroscopically-confirmed members. Rest-frame optical colors and visual morphologies were obtained primarily from Hubble Space Telescope images. Morphology-density relations (MDR) are derived in each cluster from a complete, luminosity-selected sample of 452 galaxies with a magnitude limit M_V < M^{*}_{V} + 1. The change in the early-type fraction with redshift matches previous work for massive clusters of galaxies. We performed a similar analysis, deriving MDRs for complete, mass-selected samples of 441 galaxies with a mass-limit of 10^{10.6} M_{\sun}. Our mass limit includes faint objects, the equivalent of =~1 mag below L^{*} for the red cluster galaxies, and encompasses =~70% of the stellar mass in cluster galaxies. The MDRs in the mass-selected sample at densities of Sigma > 50 galaxies Mpc^{-2} are similar to those in the luminosity-selected sample but show larger early-type fractions. However, the trend with redshift in the fraction of elliptical and S0 galaxies with masses > 10^{10.6} M_{\sun} differs significantly between the mass- and luminosity-selected samples. The clear trend seen in the early-type fraction from z=0 to z=~ 0.8 is not found in mass-selected samples. The early-type galaxy fraction changes much less, and is consistent with being constant at 92% +/- 4% at \Sigma> 500 galaxies Mpc^{-2} and 83 +/- 3% at 50 < \Sigma < 500 galaxies Mpc^{-2}. This suggests that galaxies of mass lower than > 10^{10.6} M_{\sun} play a significant role in the evolution of the early-type fraction in luminosity-selected samples. (Abstract abridged)Comment: 18 pages in emulate ApJ format, with 10 color figures, Accepted to ApJ. Version updated to reflect published version, includes new references and a correction to table

    The Measure of a Measurement

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    While finite non-commutative operator systems lie at the foundation of quantum measurement, they are also tools for understanding geometric iterations as used in the theory of iterated function systems (IFSs) and in wavelet analysis. Key is a certain splitting of the total Hilbert space and its recursive iterations to further iterated subdivisions. This paper explores some implications for associated probability measures (in the classical sense of measure theory), specifically their fractal components. We identify a fractal scale ss in a family of Borel probability measures μ\mu on the unit interval which arises independently in quantum information theory and in wavelet analysis. The scales ss we find satisfy sR+s\in \mathbb{R}_{+} and s1s\not =1, some s1s 1. We identify these scales ss by considering the asymptotic properties of μ(J)/Js\mu(J) /| J| ^{s} where JJ are dyadic subintervals, and J0| J| \to0.Comment: 18 pages, 3 figures, and reference

    The LCO/Palomar 10,000 km/sec Cluster Survey. II. Constraints on Large-Scale Streaming

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    The LCO/Palomar 10,000 km/sec (LP10K) Tully-Fisher (TF) data set is used to test for bulk streaming motions on a ~150 Mpc scale. The sample consists of 172 cluster galaxies in the original target range of the survey, 9000-13,000 km/sec, plus an additional 72 galaxies with cz < 30,000 km/sec. A maximum-likelihood analysis that is insensitive to Malmquist and selection bias effects is used to constrain the bulk velocity parameters, and realistic Monte-Carlo simulations are carried out to correct residual biases and determine statistical errors. When the analysis is restricted to the original target range, the bias-corrected bulk flow is v_B=720 +/- 280 km/sec toward l=266, b=19. When all objects out to z=0.1 are included the result is virtually unchanged, v_B=700 +/- 250 km/sec toward l=272, b=10. The hypothesis that the Hubble flow has converged to the CMB frame at distances less than ~ 100 Mpc is ruled out at the 97% confidence level. The data are inconsistent with the flow vector found by Lauer & Postman. However, the LP10K bulk flow is consistent with that obtained from the SMAC survey of elliptical galaxies recently described by Hudson et al. If correct, the LP10K results indicate that the convergence depth for the Hubble flow is >~ 150 Mpc.Comment: 14 pages, 7 figures, uses emulateapj, submitted to the Astrophysical Journal. Also available at http://astro.stanford.edu/jeff

    Gestational psittacosis in a Montana sheep rancher.

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    In humans, psittacosis is primarily a flulike illness following exposure to psittacine birds. In rare cases, pregnant women exposed to Chlamydia psittaci can contract gestational psittacosis: atypical pneumonia, sepsis, and placental insufficiency resulting in premature birth or miscarriage. In the United States, only two cases of gestational psittacosis have been reported, both from exposure to psittacine birds. Eleven other cases have been reported worldwide, mostly in the United Kingdom, all from exposure to infected birth fluids and membranes of farm mammals, notably sheep and goats. In these mammals, C. psittaci inhabit the reproductive tract, are transmitted sexually or by the fecal-oral route, and cause miscarriages. The case of gestational psittacosis in a Montana sheep rancher is the first farm animal-related case reported in the United States. Pregnant women should avoid close contact with C. psittaci-infected animals, particularly sheep and goats during the birthing season. Obstetricians should consider this diagnosis along with early antibiotic treatment and cesarean section delivery in the context of the patient's case history

    University of Akron Symphonic Band (Apr 21, 2013)

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    Final formal concert at UA. Includes Paragon brass and piece commissioned for UA Symphonic Band in 2003; Mr. Jorgensen conducting.https://ideaexchange.uakron.edu/rdjorgensen_ideas/1025/thumbnail.jp
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