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Item The Adminstration of Public Education in Centralized and Coordinated Schools(University of Texas at Austin, 1928-03-08) University of Texas at AustinItem Halo Streams In The Seventh Sloan Digital Sky Survey Data Release(2009-06) Klement, R.; Rix, Hans-Walter; Flynn, C.; Fuchs, B.; Beers, Timothy C.; Prieto, Carlos Allende; Bizyaev, Dmitry; Brewington, Howard; Lee, Y. S.; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Dan; Pan, K.; Fiorentin, P. R.; Simmons, Audrey; Snedden, Stephanie; Prieto, Carlos AllendeWe have detected stellar halo streams in the solar neighborhood using data from the seventh public data release of the Sloan Digital Sky Survey (SDSS), which includes the directed stellar program Sloan Extension For Galactic Understanding and Exploration (SEGUE). In order to derive distances to each star, we used the metallicity-dependent photometric parallax relation from Ivezic et al. We examine and quantify the accuracy of this relation by applying it to a set of globular and open clusters observed by the SDSS/SEGUE and comparing the resulting sequence to the fiducial cluster sequences obtained by An et al. Our final sample consists of 22,321 nearby (d <= 2 kpc), metal-poor ([Fe/H] <= -0.5) main-sequence stars with six-dimensional estimates of position and space velocity ((r) over bar, (v) over bar). We characterize the orbits of these stars through suitable kinematic proxies for their "effective" integrals of motion, angular momentum, eccentricity, and orbital polar angle and compare the observed distribution to expectations from a smooth distribution in four [Fe/H] bins. The metallicities provide an additional dimension in parameter space that is well suited to distinguish tidal streams from those of dynamical origin. On this basis, we identify at least five significant "phase-space overdensities" of stars on very similar orbits in the solar neighborhood to which we can assign unambiguously peaked [Fe/H] distributions. Three of them have been identified previously, including the halo stream discovered by Helmi et al. at a significance level of sigma = 12.0. In addition, we find at least two new genuine halo streams, judged by their kinematics and [Fe/H], at sigma = 2.9 and 4.8, respectively. For one stream the stars even show coherence in the configuration space, matching a spatial overdensity of stars found by Juric et al. at (R, z) approximate to (9.5, 0.8) kpc. Our results demonstrate the practical power of our search method to detect substructure in the phase-space distribution of nearby stars without making a priori assumptions about the detailed form of the gravitational potential.Item Letter to Atsuyuki Mizuno from H.B. Stenzel on 1964-11-12(1964-11-12) Stenzel, H.B.Item Letter to Burton A. Amundson from H.B. Stenzel on 1969-07-03(1969-07-03) Stenzel, Henryk B.Item Letter to C.M. Yonge from H.B. Stenzel on 1963-10-03(1963-10-03) Stenzel, Henryk B.Item Letter to Dan E. Feray from H.B. Stenzel on 1953-07-23(1953-07-23) Stenzel, Henryk B.Item Letter to G.H. Bassett from H.B. Stenzel on 1964-04-30(1964-04-30) Stenzel, Henryk B.Item Letter to H.A. Pilsbry from H.B. Stenzel on 1940-08-14(1940-08-14) Stenzel, H.B.Item Letter to H.B. Stenzel from Arthur A. Baker on 1961-01-06(1961-01-06) Baker, Arthur A.Item Letter to H.B. Stenzel from Calvin Goodrich on 1944-09-15(1944-09-15) Goodrich, CalvinItem Letter to H.B. Stenzel from Curt Teichert on 1969-01-13(1969-01-13) Teichert, CurtItem Letter to H.B. Stenzel from Curtis J. Hesse on 1943-08-09(1943-08-09) Hesse, Curtis J.Item Letter to H.B. Stenzel from Dan E. Feray on 1948-04-10(1948-04-10) Feray, Dan E.Item Letter to H.B. Stenzel from Dan E. Feray on 1948-04-22(1948-04-22) Feray, Dan E.Item Letter to H.B. Stenzel from H.R. Aldrich on 1941-03-25(1941-03-25) Aldrich, H.R.Item Letter to H.B. Stenzel from Helen M. Muir Wood on 1960-05-20(1960-05-20) Muir Wood, Helen M.Item Letter to H.B. Stenzel from Henry A. Pilsbry on 1940-05-16(1940-05-16) Pilsbry, Henry A.Item Letter to H.B. Stenzel from Norman D. Newell on 1947-12-22(1947-12-22) Newell, Norman D.Item Letter to H.B. Stenzel from R.E. McAdams on 1935-04-08(1935-04-08) McAdams, R.E.Item Letter to H.B. Stenzel from Roy T. Hazzard on 1954-04-04(1954-04-04) Hazzard, Roy T.