Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-03T02:48:56.266Z Has data issue: false hasContentIssue false
  • English
  • Français

Galactic stellar populations: current and new perspectives

Published online by Cambridge University Press:  14 November 2014

M. Haywood
M. Haywood*
Affiliation:
GEPI, Observatoire de Paris, CNRS UMR 8111, 5 place Jules Janssen, 92195 Meudon Cedex, France
*
e-mail: [email protected]
Get access

Abstract

Present studies on the evolution of the Milky Way are driven and shaped by how we conceive its stellar populations, in an on going process started by W. Baade seventy years ago. Despite much progress and advances in our understanding of these populations, inspection of their main properties is however hardly indicative of the path the Milky Way has followed to build up its mass. This is not only a matter of (stellar) age measurement, but more so the consequence of how we interprete the structures that we see in our Galaxy, often through the filter of our definitions of stellar populations. The panorama presented in the following pages opens the possibility that the present “filter” is not fully adequate. I start these Lectures with a summary of the main properties of the disks, bulge, and halo, and then present some of the new directions in the interpretation of the structure and evolution of the disk(s), with emphasis on chemical evolution. I discuss recent results in our understanding of the bulge, its stellar components and chemical evolution. Finally, I present the ideas currently proposed to explain the formation of the Galactic stellar halo. I conclude by examining how deeply all these new results question our present definition of stellar populations.

Type
Research Article
Information
European Astronomical Society Publications Series , Volume 65: The Ages of Stars , 2014 , pp. 349 - 407
Copyright
© EAS, EDP Sciences, 2014

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Adibekyan, V.Z., Sousa, S.G., Santos, N.C., et al., 2012, A&A, 545, A32
Alard, C., 2001, A&A, 379, L44
Alves-Brito, A., Meléndez, J., Asplund, M., Ramírez, I., & Yong, D., 2010, A&A, 513, A35
Anders, F., Chiappini, C., Santiago, B.X., et al., 2014, A&A, 564, A115
Athanassoula, E., & Misiriotis, A., 2002, MNRAS, 330, 35CrossRef
Baade, W., 1944, ApJ, 100, 137CrossRef
Babusiaux, C., Gómez, A., Hill, V., et al., 2010, A&A, 519, A77
Bahcall, J., Soneira, R.M., 1980, ApJS, 44, 73CrossRef
Barker, M.K., Ferguson, A.M.N., Cole, A.A., et al., 2011, MNRAS, 410, 504CrossRef
Beers, T.C., Carollo, D., Ivezić, Z., et al., 2012, ApJ, 746, 34CrossRef
Bell, E.F., Zucker, D.B., Belokurov, V., et al., 2008, ApJ, 680, 295CrossRef
Belokurov, V., Zucker, D.B., Evans, N.W., et al., 2006, ApJ, 642, L137CrossRef
Belokurov, V., 2013, New Astron. Rev., 57, 100CrossRef
Belokurov, V., Koposov, S.E., Evans, N.W., et al., 2014, MNRAS, 437, 116CrossRef
Benjamin, R.A., Churchwell, E., Babler, B.L., et al., 2005, ApJ, 630, L149CrossRef
Bensby, T., Alves-Brito, A., Oey, M.S., Young, D., & Melendez, J., 2011a, ApJ, 735, 46CrossRef
Bensby, T., Adén, D., Meléndez, J., et al., 2011b, A&A, 533, A134
Bensby, T., Yee, J.C., Feltzing, S., et al., 2013, A&A, 549, A147
Bensby, T., Feltzing, S., & Oey, M.S., 2014, A&A, 562, A71
Bica, E., Bonatto, C., Barbuy, B., & Ortolani, S., 2006, A&A, 450, 105
Binney, J., & Merrifield, M., 1998, Galactic Astronomy (Princeton: Princeton University Press)Google Scholar
Blitz, L., & Spergel, D.N., 1991, ApJ, 379, 631CrossRef
Bonaca, A., Geha, M., & Kallivayalil, N., 2012, ApJ, 760, L6CrossRef
Bournaud, F., Elmegreen, B.G., & Martig, M., 2009, ApJ, 707, L1CrossRef
Bovy, J., Rix, H.-W., & Hogg, D.W., 2012a, ApJ, 751, 131CrossRef
Bovy, J., Rix, H.-W., Liu, C., et al., 2012b, ApJ, 753, 148CrossRef
Bovy, J., Rix, H.-W., Hogg, D.W., et al., 2012c, ApJ, 755, 115CrossRef
Bovy, J., Allende Prieto, C., Beers, T.C., et al., 2012d, ApJ, 759, 131CrossRef
Bresolin, F., Kennicutt, R.C., & Ryan-Weber, E., 2012, ApJ, 750, 122CrossRef
Brown, T.M., Sahu, K., Anderson, J., et al., 2010, ApJ, 725, L19CrossRef
Brown, T.M., Tumlinson, J., Geha, M., et al., 2013, in EWASS 2013 Symposium 5: Local Group, Local Cosmology, ed. Salvadori, S. & Monelli, M., Mem. Soc. Astron. Ital., in press [arXiv.org/abs/1310.0824]Google Scholar
Cabrera-Lavers, A., Hammersley, P.L., González-Fernández, C., et al., 2007, A&A, 465, 825
Cabrera-Lavers, A., González-Fernández, C., Garzón, F., Hammersley, P.L., & López-Corredoira, M., 2008, A&A, 491, 781
Carilli, C.L., & Walter, F., 2013, ARA&A, 51, 105CrossRef
Carollo, D., Beers, T.C., Lee, Y.S., et al., 2007, Nature, 450, 1020CrossRef
Carollo, D., Beers, T.C., Chiba, M., et al., 2010, ApJ, 712, 692CrossRef
Casey, A.R., Keller, S.C., Da Costa, G., Frebel, A., & Maunder, E., 2014, ApJ, 784, 19CrossRef
Casagrande, L., Schönrich, R., Asplund, M., et al., 2011, A&A, 530, A138
Cheng, J.Y., Rockosi, C.M., Morrison, H.L., et al., 2012a, ApJ, 746, 149CrossRef
Cheng, J.Y., Rockosi, C.M., Morrison, H.L., et al., 2012b, ApJ, 752, 51CrossRef
Chiappini, C., Matteucci, F., & Gratton, R., 1997, ApJ, 477, 765CrossRef
Cioni, M.-R.L., 2009, A&A, 506, 1137
Clarkson, W., Sahu, K., Anderson, J., et al., 2008, ApJ, 684, 1110CrossRef
Cockcroft, R., McConnachie, A.W., Harris, W.E., et al., 2013, MNRAS, 428, 1248CrossRef
Combes, F., Debbasch, F., Friedli, D., & Pfenniger, D., 1990, A&A, 233, 82
Da Costa, G.S., Held, E.V., & Saviane, I., 2014, MNRAS, 438, 3507CrossRef
de Jong, J.T.A., Yanny, B., Rix, H.-W., et al., 2010, ApJ, 714, 663CrossRef
de Vaucouleurs, G., 1959, Handbuch der Physik, 53, 311CrossRef
Roškar, R., Debattista, V.P., Loebman, S.R., Ivezić, Z., & Quinn, T.R., 2011, in 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, ASP Conf. Ser., Vol. 448, ed. Johns-Krull, C.M., Browning, M.K. & West, A.A., p. 371
de Vaucouleurs, G., & Pence, W., 1978, AJ, 83, 1163CrossRef
del Pino, A., Hidalgo, S.L., Aparicio, A., et al., 2013, MNRAS, 433, 1505CrossRef
Deason, A.J., Belokurov, V., & Evans, N.W., 2011, MNRAS, 416, 2903CrossRef
Decressin, T., Meynet, G., Charbonnel, C., Prantzos, N., & Ekström, S., 2007, A&A, 464, 1029
Dekel, A., Birnboim, Y., Engel, G., et al., 2009, Nature, 457, 451CrossRef
Di Matteo, P., Lehnert, M.D., Qu, Y., & van Driel, W., 2011, A&A, 525, L3
Di Matteo, P., Haywood, M., Gomez, A., et al., 2014, A&A, 567, A122
Dinescu, D.I., Girard, T.M., & van Altena, W.F., 1999, AJ, 117, 1792CrossRef
Drake, A.J., Catelan, M., Djorgovski, S.G., et al., 2013, ApJ, 765, 154CrossRef
Edvardsson, B., Andersen, J., Gustafsson, B., et al., 1993, A&A, 275, 101
Eggen, O.J., Lynden-Bell, D., & Sandage, A.R., 1962, ApJ, 136, 748CrossRef
Elmegreen, B.G., & Elmegreen, D.M., 2006, ApJ, 650, 644CrossRef
Elmegreen, B.G., Bournaud, F., & Elmegreen, D.M., 2008, ApJ, 688, 67CrossRef
Erwin, P., Beckman, J.E., & Pohlen, M., 2005, ApJ, 626, L81CrossRef
Fadely, R., Willman, B., Geha, M., et al., 2011, AJ, 142, 88CrossRef
Fathi, K., 2010, ApJ, 722, L120CrossRef
Fenner, Y., Gibson, B.K., & Limongi, M., 2002, Ap&SS, 281, 537
Fisher, D.B., & Drory, N., 2010, ApJ, 716, 942CrossRef
Flynn, C., Holmberg, J., Portinari, L., Fuchs, B., & Jahreiß, H., 2006, MNRAS, 372, 1149CrossRef
Forbes, D.A., & Bridges, T., 2010, MNRAS, 404, 1203
Zinn, R., 1993, in The Globular Cluster-Galaxy Connection, ASP Conf. Ser. Vol. 48, ed. Smith, G.H. & Brodie, J.P., p. 38Google Scholar
Frebel, A., & Norris, J.E., 2013, in Planets, Stars and Stellar Systems, Volume 5: Galactic Structure and Stellar Populations, ed. Oswalt, T.D. & Gilmore, G. (Berlin: Springer), p. 55CrossRefGoogle Scholar
Freeman, K.C., 1970, ApJ, 160, 811CrossRef
Freeman, K., & Bland-Hawthorn, J., 2002, ARA&A, 40, 487CrossRef
Fuhrmann, K., 1998, A&A, 338, 161
Fuhrmann, K., 2011, MNRAS, 414, 2893CrossRef
Fuhrmann, K., Chini, R., Hoffmeister, V.H., & Bernkopf, J., 2012, MNRAS, 420, 1423CrossRef
Genzel, R., Tacconi, L.J., Eisenhauer, F., et al., 2006, Nature, 442, 786CrossRef
Gilmore, G., Reid, N., 1983, MNRAS, 202, 1025CrossRef
Golubov, O., Just, A., Bienaymé, O., et al., 2013, A&A, 557, A92
Gonzalez, O.A., Rejkuba, M., Zoccali, M., et al., 2011, A&A, 530, A54
Gratton, R.G., Carretta, E., & Bragaglia, A., 2012, A&ARv, 20, 50
Grenon, M., 1972, in Âge des Étoiles, IAU Colloq. 17, ed. Cayrel de Strobel, G. & Delplace, A.M. (Meudon: Observatoire de Paris), p. 55Google Scholar
Grieco, V., Matteucci, F., Pipino, A., & Cescutti, G., 2012, A&A, 548, A60
Grillmair, C.J., & Johnson, R., 2006, ApJ, 639, L17CrossRef
Grillmair, C.J., 2009, ApJ, 693, 1118CrossRef
Hammer, F., Puech, M., Chemin, L., Flores, H., & Lehnert, M.D., 2007, ApJ, 662, 322CrossRef
Hammersley, P.L., Garzón, F., Mahoney, T.J., López-Corredoira, M., & Torres, M.A.P., 2000, MNRAS, 317, L45CrossRef
Harris, W.E., 2010, A New Catalog of Globular Clusters in the Milky Way [arXiv:1012.3224]
Haywood, M., 2006, MNRAS, 371, 1760CrossRef
Haywood, M., 2008, MNRAS, 388, 1175CrossRef
Haywood, M.,Di Matteo, P., Lehnert, M., Katz, D., & Gómez, A., 2013, A&A, 560, A109
Haywood, M., 2014a, Mem. Soc. Astron. Ital. Suppl., 25, 11
Haywood, M., 2014b, in Lessons from the Local Group – A Conference in Honour of David Block and Bruce Elmegreen, ed. Freeman, K.C., Elmegreen, B.G., Block, D.L. & Woolway, M. (Berlin: Springer), in press
Helmi, A., 2008, A&ARv, 15, 145
Hill, V., Lecureur, A., Gómez, A., et al., 2011, A&A, 534, A80PubMed
Hopkins, P.F., Keres, D., Onorbe, J., et al., 2013 [arXiv:1311.2073]
Ibata, R.A., Gilmore, G., & Irwin, M.J., 1994, Nature, 370, 194CrossRef
Ibata, R., Irwin, M., Lewis, G.F., & Stolte, A., 2001a, ApJ, 547, L133CrossRef
Ibata, R., Irwin, M., Lewis, G., Ferguson, A.M.N., & Tanvir, N., 2001b, Nature, 412, 49CrossRef
Ibata, R.A., Lewis, G.F., McConnachie, A.W., et al., 2014, ApJ, 780, 128CrossRef
Ivezić, Z., Beers, T.C., & Jurić, M., 2012, ARA&A, 50, 251CrossRef
Iwamoto, K., Brachwitz, F., Nomoto, K., et al., 1999, ApJS, 125, 439CrossRef
Janes, K.A., & McClure, R.D., 1972, BAAS, 4, 241
Jayaraman, A., Gilmore, G., Wyse, R.F.G., Norris, J.E., & Belokurov, V., 2013, MNRAS, 431, 930CrossRef
Johnson, C.I., & Pilachowski, C.A., 2010, ApJ, 722, 1373CrossRef
Jurić, M., Ivezić, Z., Brooks, A., et al., 2008, ApJ, 673, 864CrossRef
Karachentsev, I.D., & Makarov, D.A., 1996, AJ, 111, 794CrossRef
Keller, S.C., Bessell, M.S., Frebel, A., et al., 2014, Nature, 506, 463CrossRef
Kirby, E.N., Cohen, J.G., Smith, G.H., et al., 2011, ApJ, 727, 79CrossRef
Koposov, S.E., Belokurov, V., Evans, N.W., et al., 2012, ApJ, 750, 80CrossRef
Kordopatis, G., Gilmore, G., Wyse, R.F.G., et al., 2013, MNRAS, 436, 3231CrossRef
Kormendy, J., & Kennicutt, R.C. Jr., 2004, ARA&A, 42, 603CrossRef
Kormendy, J., Drory, N., Bender, R., & Cornell, M.E., 2010, ApJ, 723, 54CrossRef
Kormendy, J., 2013, in Secular Evolution of Galaxies, ed. Falcón-Barroso, J. & Knapen, J.H. (Cambridge: Cambridge University Press), p. 1Google Scholar
Kraljic, K., Bournaud, F., & Martig, M., 2012, ApJ, 757, 60CrossRef
Kroupa, P., 2001, MNRAS, 322, 231CrossRef
Kuijken, K., & Rich, R.M., 2002, AJ, 124, 2054CrossRef
Kunder, A., Koch, A., Rich, R.M., et al., 2012, AJ, 143, 57CrossRef
Lagioia, E.P., Milone, A.P., Bono, G., et al., 2014 [arXiv:1402.0981]
Larson, R.B., 1976, MNRAS, 176, 31CrossRef
Law, D.R., & Majewski, S.R., 2010, ApJ, 718, 1128CrossRef
Leaman, R., VandenBerg, D.A., & Mendel, J.T., 2013, MNRAS, 436, 122CrossRef
Lee, Y.S., Beers, T.C., An, D., et al., 2011, ApJ, 738, 187CrossRef
Lehnert, M.D., Le Tiran, L., Nesvadba, N.P. H., et al., 2013, A&A, 555, A72
Lehnert, M.D., Di Matteo, P., Haywood, M., & Snaith, O.N., 2014, ApJ, 789, L30CrossRef
Li, J., Newberg, H.J., Carlin, J.L., et al., 2012, ApJ, 757, 151CrossRef
Liu, C., & van de Ven, G., 2012, MNRAS, 425, 2144CrossRef
Loebman, S.R., Roškar, R., Debattista, V.P., et al., 2011, ApJ, 737, 8CrossRef
Longmore, A.J., Kurtev, R., Lucas, P.W., et al., 2011, MNRAS, 416, 465
López-Corredoira, M., Cabrera-Lavers, A., Mahoney, T.J., et al., 2007, AJ, 133, 154CrossRef
Mackey, A.D., & Gilmore, G.F., 2004, MNRAS, 355, 504CrossRef
Mackey, A.D., & van den Bergh, S., 2005, MNRAS, 360, 631CrossRef
Marín-Franch, A., Herrero, A., Lenorzer, A., et al., 2009, A&A, 502, 559
Martell, S.L., Smolinski, J.P., Beers, T.C., & Grebel, E.K., 2011, A&A, 534, A136
Martinez-Valpuesta, I., & Gerhard, O., 2011, ApJ, 734, L20CrossRef
Massari, D., Ferraro, F.R., Mucciarelli, A., et al., 2014, Mem. Soc. Astron. Ital., 85, 249
Mauro, F., Moni Bidin, C., Cohen, R., et al., 2012, ApJ, 761, L29CrossRef
McGaugh, S.S., Schombert, J.M., Bothun, G.D., & de Blok, W.J.G., 2000, ApJ, 533, L99CrossRef
McConnachie, A.W., 2012, AJ, 144, 4CrossRef
McWilliam, A., & Zoccali, M., 2010, ApJ, 724, 1491CrossRef
Meléndez, J., Asplund, M., Alves-Brito, A., et al., 2008, A&A, 484, L21
Micali, A., Matteucci, F., & Romano, D., 2013, MNRAS, 436, 1648CrossRef
Minchev, I., & Famaey, B., 2010, ApJ, 722, 112CrossRef
Monaco, L., Saviane, I., Correnti, M., Bonifacio, P., & Geisler, D., 2011, A&A, 525, A124
Morrison, H.L., Flynn, C., & Freeman, K.C., 1990, AJ, 100, 1191CrossRef
Morrison, H.L., Helmi, A., Sun, J., et al., 2009, ApJ, 694, 130CrossRef
Muzzin, A., Marchesini, D., Stefanon, M., et al., 2013, ApJ, 777, 18CrossRef
Naab, T., & Ostriker, J.P., 2006, MNRAS, 366, 899CrossRef
Nataf, D.M., Udalski, A., Gould, A., Fouqué, P., & Stanek, K.Z., 2010, ApJ, 721, L28CrossRef
Navarro, J.F., Abadi, M.G., Venn, K.A., Freeman, K.C., & Anguiano, B., 2011, MNRAS, 412, 1203
Ness, M., Freeman, K., Athanassoula, E., et al., 2013a, MNRAS, 430, 836CrossRef
Ness, M., Freeman, K., Athanassoula, E., et al., 2013b, MNRAS, 432, 2092CrossRef
Ness, M., Debattista, V.P., Bensby, T., et al., 2014, ApJ, 787, L19CrossRef
Newberg, H.J., Yanny, B., Grebel, E.K., et al., 2003, ApJ, 596, L191CrossRef
Newberg, H.J., Willett, B.A., Yanny, B., & Xu, Y., 2010, ApJ, 711, 32CrossRef
Newby, M., Cole, N., Newberg, H.J., et al., 2013, AJ, 145, 163CrossRef
Niederste-Ostholt, M., Belokurov, V., Evans, N.W., & Peñarrubia, J., 2010, ApJ, 712, 516CrossRef
Nissen, P.E., & Schuster, W.J., 2010, A&A, 511, L10
Nittler, L.R., 2005, ApJ, 618, 281CrossRef
Norris, J., 1987, ApJ, 314, L39CrossRef
Origlia, L., Massari, D., Rich, R.M., et al., 2013, ApJ, 779, L5CrossRef
Przybilla, N., 2008, Rev. Mod. Astron., 20, 323CrossRef
Recio-Blanco, A., de Laverny, P., Kordopatis, G., et al., 2014, A&A, 567, A5
Reddy, B.E., Lambert, D.L., & Allen de Prieto, C., 2006, MNRAS, 367, 1329CrossRef
Reid, M.J., Menten, K.M., Brunthaler, A., et al., 2014, ApJ, 783, 130CrossRef
Rix, H.-W., & Bovy, J., 2013, A.&ARv, 21, 61
Robin, A.C., Reylé, C., Derrière, S., & Picaud, S., 2003, A&A, 409, 523
Rosenberg, A., Saviane, I., Piotto, G., Aparicio, A., & Zaggia, S.R., 1998, AJ, 115, 648CrossRef
Roškar, R., Debattista, V.P., Loebman, S.R., Ivezić, Z., & Quinn, T.R., 2011, in 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, ASP Conf. Ser., Vol. 448, ed. Johns-Krull, C.M., Browning, M.K. & West, A.A., p. 371Google Scholar
Roškar, R., Debattista, V.P., & Loebman, S.R., 2013, MNRAS, 433, 976CrossRef
Sandage, A., 1986, ARA&A, 24, 421CrossRef
Schaerer, D., & Charbonnel, C., 2011, MNRAS, 413, 2297CrossRef
Schmidt, M., 1963, ApJ, 137, 758CrossRef
Schönrich, R., & Binney, J., 2009, MNRAS, 396, 203CrossRef
Schönrich, R., 2012, EPJ Web of Conferences, 19, 5003CrossRef
Schönrich, R., Asplund, M., & Casagrande, L., 2014, ApJ, 786, 7CrossRef
Schuster, W.J., Moreno, E., Nissen, P.E., & Pichardo, B., 2012, A&A, 538, A21
Seabroke, G.M., & Gilmore, G., 2007, MNRAS, 380, 1348CrossRef
Searle, L., & Zinn, R., 1978, ApJ, 225, 357CrossRef
Sellwood, J.A., & Binney, J.J., 2002, MNRAS, 336, 785CrossRef
Sellwood, J.A., 2014, Rev. Mod. Phys., 86, 1CrossRef
Shen, J., Rich, R.M., Kormendy, J., et al., 2010, ApJ, 720, L72CrossRef
Sheth, K., Elmegreen, D.M., Elmegreen, B.G., et al., 2008, ApJ, 675, 1141CrossRef
Shlosman, I., 2013, in Secular Evolution of Galaxies, ed. Falcón-Barroso, J. & Knapen, J.H. (Cambridge: Cambridge University Press), p. 555CrossRefGoogle Scholar
Siegel, M.H., Majewski, S.R., Law, D.R., et al., 2011, ApJ, 743, 20CrossRef
Simon, J.D., & Geha, M., 2007, ApJ, 670, 313CrossRef
Snaith, O.N., Haywood, M., Di Matteo, P., et al., 2014, ApJ, 781, L31CrossRef
Soderblom, D.R., 2010, ARA&A, 48, 581CrossRef
Soto, M., Rich, R.M., & Kuijken, K., 2007, ApJ, 665, L31CrossRef
Spitzer, L., & Schwarzschild, M., 1951, ApJ, 114, 385CrossRef
Swinbank, A.M., Papadopoulos, P.P., Cox, P., et al., 2011, ApJ, 742, 11CrossRef
Tinsley, B.M., 1974, ApJ, 192, 629CrossRef
Tinsley, B.M., 1980, Fund. Cosmic Phys., 5, 287
Tsujimoto, T., & Bekki, K., 2012, ApJ, 747, 125CrossRef
Tully, R.B., & Fisher, J.R., 1977, A&A, 54, 661PubMed
Uttenthaler, S., Schultheis, M., Nataf, D.M., et al., 2012, A&A, 546, A57
van den, Bergh, S., 1962, AJ, 67, 486CrossRef
van den, Bergh, S., 2000, ApJ, 530, 777CrossRef
van der Kruit, P.C., & Freeman, K.C., 2011, ARA&A, 49, 301CrossRef
VandenBerg, D.A., Brogaard, K., Leaman, R., & Casagrande, L., 2013, ApJ, 775, 134CrossRef
van Dokkum, P.G., Leja, J., Nelson, E.J., et al., 2013, ApJ, 771, L35CrossRef
Vargas, L.C., Geha, M., Kirby, E.N., & Simon, J.D., 2013, ApJ, 767, 134CrossRef
Vásquez, S., Zoccali, M., Hill, V., et al., 2013, A&A, 555, A91
Ventura, P., D'Antona, F., Mazzitelli, I., & Gratton, R., 2001, ApJ, 550, L65CrossRef
Wegg, C., & Gerhard, O., 2013, MNRAS, 435, 1874CrossRef
Weiland, J.L., Arendt, R.G., Berriman, G.B., et al., 1994, ApJ, 425, L81CrossRef
Widrow, L.M., Gardner, S., Yanny, B., Dodelson, S., & Chen, H.-Y., 2012, ApJ, 750, L41CrossRef
Wielen, R., 1977, A&A, 60, 263PubMed
Xue, X.-X., Ma, Z., Rix, H.-W., et al., 2014, ApJ, 784, 170CrossRef
Yong, D., Carney, B.W., & Friel, E.D., 2012, AJ, 144, 95CrossRef
Zinn, R., 1993, in The Globular Cluster-Galaxy Connection, ASP Conf. Ser. Vol. 48, ed. Smith, G.H. & Brodie, J.P., p. 38Google Scholar
Zoccali, M., Renzini, A., Ortolani, S., et al., 2003, A&A, 399, 931
Zoccali, M., Gonzalez, O.A., Vasquez, S., et al., 2014, A&A, 562, A66