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31.
L.R. Bedin J. Anderson D.C. Heggie G. Piotto A.P. Milone M. Giersz V. Nascimbeni A. Bellini R.M. Rich M. van den Berg D. Pooley K. Brogaard S. Ortolani L. Malavolta L. Ubeda A.F. Marino 《Astronomische Nachrichten》2013,334(10):1062-1085
We present an overview of the ongoing Hubble Space Telescope large program GO‐12911. The program is focused on the core of M 4, the nearest Galactic globular cluster, and the observations are designed to constrain the number of binaries with massive companions (black holes, neutron stars, or white dwarfs) by measuring the “wobble” of the luminous (mainsequence) companion around the center of mass of the pair, with an astrometric precision of ∼50 µas. The high spatial resolution and stable medium‐band PSFs of WFC3/UVIS will make these measurements possible. In this work we describe (i) the motivation behind this study, (ii) our observing strategy, (iii) the many other investigations enabled by this unique data set, and which of those our team is conducting, and (iv) a preliminary reduction of the first‐epoch dataset collected on 2012 October 10. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
32.
The Halley PACE HF radar has been operated in a new mode to provide very high time (10 s) and space (15 km) resolution measurements of the iono-spheric signatures of the cusp and the low-latitude boundary layer. The first data show that the iono-spheric signature of flux transfer events occur up to 300 km equatorward of regions showing the HF characteristics of the ionospheric cusp. Whilst larger flux transfer events are seen, on average, every 7 min, many much smaller and short-duration events have been identified. On one occasion DMSP data have been used to show that at least four flux transfer events are occurring simultaneously at the edge of the cusp over 2 h of MLT. There is strong, but not conclusive evidence, that reconnection at the magnetopause is both intermittent and patchy. These data also suggest that flux transfer events can be a significant contributor to the cross-polar cap potential. 相似文献
33.
34.
L. Origlia E. Valenti R. M. Rich 《Monthly notices of the Royal Astronomical Society》2005,356(4):1276-1282
Using the Near Infrared Spectrometer (NIRSPEC) spectrograph at Keck II, we have obtained infrared (IR) echelle spectra covering the range 1.5 –1.8 μm for the moderately reddened bulge globular clusters NGC 6342 and 6528, finding [Fe/H]=−0.60 and −0.17 dex, respectively. We measure an average α-enhancement of ≈+0.33 dex in both clusters, consistent with previous measurements on other metal-rich bulge clusters, and favouring the scenario of a rapid bulge formation and chemical enrichment. We also measure very low 12 C/13 C isotopic ratios (≈5 in NGC 6342 and ≈8 in NGC 6528), suggesting that extra-mixing mechanisms resulting from cool bottom processing are at work during evolution along the red giant branch (RGB). 相似文献
35.
R. Michael Rich 《Astrophysics and Space Science》1999,265(1-4):453-460
This review considers implications regarding galaxy formationand evolution that can be drawn from study of the ages,abundances,
and kinematics of stellar populations in the LocalUniverse. The wide abundance range in the Galactic bulge and in thehalo
of M31 is consistent with chemical evolution in a starburstwith wind outflow. We question the notionthat the Galactic halo
population is assembled fromdisrupted dwarf spheroidal galaxies, based on the presenceof metal rich stars in Local Group halos.The
alpha-element enhancements of bulge giants are those expected from a system forming on a timescale of less than 1 Gyr. Direct
measurement of the star formationhistory from turnoff photometry in Local Group galaxiesis not in complete agreement with
the universal star formation rateinferred from high redshift studies. We argue that the properties of the Local Universe constrain
galaxyformation theory just as strongly as the findings gleaned fromhigh redshift galaxies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
36.
A. Pastorello P. A. Mazzali G. Pignata S. Benetti E. Cappellaro A. V. Filippenko W. Li W. P. S. Meikle A. A. Arkharov G. Blanc F. Bufano A. Derekas M. Dolci N. Elias-Rosa R. J. Foley M. Ganeshalingam A. Harutyunyan L. L. Kiss R. Kotak V. M. Larionov J. R. Lucey N. Napoleone H. Navasardyan F. Patat J. Rich S. D. Ryder M. Salvo B. P. Schmidt V. Stanishev P. Székely S. Taubenberger S. Temporin M. Turatto W. Hillebrandt 《Monthly notices of the Royal Astronomical Society》2007,377(4):1531-1552
37.
Rich A. Vollenweider 《Aquatic Sciences - Research Across Boundaries》1948,10(4):53-64
Ohne Zusammenfassung 相似文献
38.
Spatial regression models were used to predict yields (kg?ha?1?yr?1) of nitrogen (N) and phosphorus (P) discharged from catchments throughout New Zealand under natural and current conditions. The models were derived using loads (kg?yr?1) of TN, NO3-N, TP and DRP calculated for 592 river water quality monitoring sites. Anthropogenic increases in yields above natural levels were associated with the proportions of catchments occupied by the intensive agricultural land cover and were unevenly distributed across regions. Anthropogenic increases in national loads of TN, NO3-N, TP and DRP exported to the ocean were 74%, 159%, 48% and 18%, respectively. Increases in loads exported to the ocean varied considerably at smaller scales, with catchments having significant load increases between 4- and 26-fold for N and 6- to 9-fold for P. Predictions of yields and loads reported here have utility in the development of strategies to manage nutrients. 相似文献
39.
40.
Michael A. Dopita Lee Armus Lisa J. Kewley Jeff A. Rich Dave Sanders Phillip N. Appleton Ben H. P. Chan Vassilis Charmandaris Aaron S. Evans David T. Frayer Justin H. Howell Hanae Inami Joseph A. Mazzarella Andreea Petric Sabrina Stierwalt Jason Surace 《Astrophysics and Space Science》2011,333(1):225-239
This paper describes a pilot study into the spectral energy distribution (SED) fitting and the derivation of physical parameters for 19 galaxies observed as part of the Great Observatories All-sky LIRG Survey (GOALS) survey as observed with the Spitzer Space Telescope. For this we have used the pan-spectral fitting tools developed in a series of papers by Dopita and his co-workers. We show that the standard Lee and Draine ??astronomical silicate?? model cannot provide a good fit to the silicate absorption features as observed in the heavily dust-extinguished (A V??50 mag.) starbursts. We have derived an empirical fit to the ??starburst silicate?? absorption in these objects. This absorption curve is consistent with the silicate grains being systematically larger in starburst environments than in the local Galactic interstellar medium. We demonstrate the sensitivity of the SED fitting to each of the fitted parameters, and derive these parameters for those galaxies which do not have an embedded AGN. This technique is simple and provides reasonably robust and uniform parameters for the starburst, especially as far as the star formation rate, population of old stars, compactness of the starburst region and total foreground extinction are concerned. However, the chemical abundances and the optical extinction cannot be reliably determined by this analysis, and optical SEDs will also be required to provide a complete characterization of the starburst region and of the surrounding galaxy. 相似文献