J. S. Silva,^1,2 W. J. Schuster,¹ and M. E. Contreras¹

¹ Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 877, 22800 Ensenada, B.C., México. (mcontreras@astrosen.unam.mx, schuster@astrosen.unam.mx, jsilva@astrosen.unam.mx).

² Observatório Nacional/MCT. Rua Gal. Jose Cristino 77, São Cristóvão, CEP20291–400 Rio de Janeiro RJ, Brazil. (jsergio@on.br).

Received 2011 October 20.
Accepted 2012 January 10.

RESUMEN

Se ha examinado la posible presencia de grupos en movimiento en el Halo galáctico en base a la nueva fotometría uvby — β de 143 estrellas pobres en metales, unida a la fotometría de las 1533 estrellas de los catálogos previos de Schuster & Nissen (1988), Schuster et al. (1993) y Schuster et al. (2006). Este nuevo conjunto de datos fotometricos junto con la velocidad radial y los movimientos propios tomados de la literatura permitiá obtener las componentes de velocidad galáctica U', V', y W' para casi toda la muestra. Con esta información cinemática se obtuvieron tres diagramas: [Fe/H] vs V_rot, Bottlinger (V' vs U') y Toomre (V' vs (U'² + W'²)^1/2), usados para identificar grupos de estrellas comunes a cada uno de ellos. Una vez identificados, se compararon con grupos en movimiento reportados en la literatura. En particular, se identificaron posibles miembros de los grupos Kapteyn y ω Cen.

ABSTRACT

The possible presence of moving groups in the local Galactic stellar halo has been examined based on new uvby — β photometry for a sample of 143 metal–poor stars joined to the photometry of 1553 stars from the previous catalogues of Schuster & Nissen (1988), Schuster et al. (1993), and Schuster et al. (2006). This new set of photometric data, together with radial velocities and proper motions taken from the literature, have allowed us to obtain Galactic space velocities U' , V' , and W' for nearly the entire sample. With this kinematic information, three diagrams: the [Fe/H] vs V_rot, the Bottlinger (V' vs U') and the Toomre (V' vs (U'² + W'²)^1/2) have been obtained and used to identify probable groups of stars in common between them. Once identified, these groups were compared to moving groups reported in the literature. In particular, probable members of the Kapteyn group and ω Cen were identified.

Key Words: Galaxy: halo — Galaxy: kinematics and dynamics — Galaxy: structure — stars: kinematics and dynamics — stars: Population II — techniques: photometric.

DESCARGAR ARTÍCULO EN FORMATO PDF

This work was supported by the Conacyt projects CB-2005-01-49434 and CB-2005-49002, and we are very appreciative of this funding which helped considerably with the data reductions and analyses. We thank very much the support and technical staff at the San Pedro Mártir Observatory for their considerable help during the taking of the uvby — β photometric data. As always, B. Hernández has helped expertly with the computer systems and software. We also thank Sean Ryan and Bruce Carney for sharing their lists of metal-poor and subgiant stars.

REFERENCES

Abadi, M. G., Navarro, J. F., Steinmetz, M., & Eke, V. R. 2003a, ApJ, 591, 499        [ Links ]

––––––––––. 2003b, ApJ, 597, 21        [ Links ]

Abt, H. A., & Biggs, E. S. 1972, Bibliography of Stellar Radial Velocities (New York: Latham Process Corp.         [ Links ])

Antoja, T., Figueras, F., Fernández, D., & Torra, J. 2008, A & A, 490, 135        [ Links ]

Antoja, T., Figueras, F., Romero–Gómez, M., Pichardo, B., Valenzuela, O., & Moreno, E. 2011, MNRAS, 418, 1423        [ Links ]

Antoja, T., Figueras, F., Torra, J., Valenzuela, O., & Pichardo, B. 2010, Lecture Notes Essays Astrophys. IV, 4, 13        [ Links ]

Antoja, T., Valenzuela, O., Pichardo, B., Moreno, E., Figueras, F., & Fernández, D. 2009, ApJ, 700, L78        [ Links ]

Asiain, R., Figueras, F., Torra, J., & Chen, B. 1999, A & A, 341, 427        [ Links ]

Barbier–Brossat, M., & Figon, P. 2000, A & AS, 142, 217        [ Links ]

Barbier–Brossat, M., Petit, M., & Figon, P. 1994, A & AS, 108, 603        [ Links ]

Barrado y Navascués, D. 1998, A & A, 339, 831        [ Links ]

Bekki, K., & Freeman, K. C. 2003, MNRAS, 346, L11        [ Links ]

Carney, B. W., Latham, D. W., Laird, J. B., & Aguilar, L. A. 1994, AJ, 107, 2240        [ Links ]

Chereul, E., Crézé, M., & Bienaymé, O. 1998, A & A, 340, 384        [ Links ]

Correnti, M., Bellazzini, M., Ibata, R. A., Ferraro, F. R., & Varghese, A. 2010, ApJ, 721, 329        [ Links ]

Crawford, D. L. 1975, AJ, 80, 955        [ Links ]

Crawford, D. L., & Barnes, J. V. 1970, AJ, 75, 978        [ Links ]

Crawford, D. L., & Mander, J. 1966, AJ, 71, 114        [ Links ]

Dehnen, W. 1998, AJ, 115, 2384        [ Links ]

––––––––––. 2000, AJ, 119, 800        [ Links ]

Dinescu, D. I. 2002, in ASP Conf. Ser. 265, Omega Centauri, A Unique Window into Astrophysics, ed. F. van Leeuwen, J. D. Hughes, & G. Piotto (San Francisco: ASP), 365        [ Links ]

Eggen, O. J. 1958, MNRAS, 118, 65        [ Links ]

––––––––––. 1960a, MNRAS, 120, 540        [ Links ]

––––––––––. 1960b, MNRAS, 120, 563        [ Links ]

––––––––––. 1965, in Galactic Structure, Vol. 5 of Stars and Stellar Systems, Chapter 6, Moving Groups of Stars, ed. A. Blaauw & M. Schimdt (Chicago: Univ. Chicago Press), 111        [ Links ]

––––––––––. 1971, PASP, 83, 271        [ Links ]

––––––––––. 1975, PASP, 87, 37        [ Links ]

––––––––––. 1977, ApJ, 215, 812        [ Links ]

––––––––––. 1983a, AJ, 88, 642        [ Links ]

––––––––––. 1983b, AJ, 88, 813        [ Links ]

––––––––––. 1983c, MNRAS, 204, 377        [ Links ]

––––––––––. 1983d, MNRAS, 204, 391        [ Links ]

––––––––––. 1984, AJ, 89, 1358        [ Links ]

––––––––––. 1990, AJ, 100, 1159        [ Links ]

––––––––––. 1991, AJ, 102, 2028        [ Links ]

––––––––––. 1992a, AJ, 103, 1302        [ Links ]

––––––––––. 1992b, AJ, 104, 1482        [ Links ]

––––––––––. 1992c, AJ, 104, 1493        [ Links ]

––––––––––. 1994, in Galactic and Solar System Optical Astrometry, ed. L. V. Morrison & G. Gilmore (Cambridge: Cambridge Univ. Press), 191        [ Links ]

––––––––––. 1995a, AJ, 110, 1749        [ Links ]

––––––––––. 1995b, AJ, 110, 2862        [ Links ]

––––––––––. 1996a, AJ, 111, 1615        [ Links ]

––––––––––. 1996b, AJ, 112, 1595        [ Links ]

––––––––––. 1996c, AJ, 112, 2661        [ Links ]

––––––––––. 1998a, AJ, 116, 284        [ Links ]

––––––––––. 1998b, AJ, 116, 782        [ Links ]

Eggen, O. J., Lynden–Bell, D., & Sandage, A. R. 1962, ApJ, 136, 748 (ELS)        [ Links ]

Eggen, O. J., & Sandage, A. R. 1959, MNRAS, 119, 255        [ Links ]

ESA 1997, The Hipparcos and Tycho Catalogues ESA SP–1200 (Noordwijk: ESA)        [ Links ]

Famaey, B., Jorissen, A., Luri, X., Mayor, M., Udry, S., Dejonghe, H., & Turon, C. 2005, A & A, 430, 165        [ Links ]

Famaey, B., Siebert, A., & Minchev, I. 2011, arXiv:1110.6176        [ Links ]

Fouts, G., & Sandage, A. 1986, AJ, 91, 1189        [ Links ]

Freeman, K., & Bland–Hawthorn, J. 2002, ARA & A, 40, 487        [ Links ]

Fux, R. 2001, A & A, 373, 511        [ Links ]

Giclas, H. L., Burnham, R., Jr., & Thomas, N. G. 1961, Lowell Obs. Bull., 5, 61        [ Links ]

––––––––––. 1975, Lowell Obs. Bull., 8, 9        [ Links ]

Giclas, H. L., Slaughter, C. D., & Burnham, R., Jr. 1959, Lowell Obs. Bull., 4, 136        [ Links ]

Goldberg, D., Mazeh, T., Latham, D., Stefanik, R., Carney, B., & Laird, J. 2002, AJ, 124, 1132        [ Links ]

Grønbech, B., Olsen, E. H., & Strömgren, B. 1976, A & AS, 26, 155        [ Links ]

Grundahl, F., VandenBerg, D. A., Stetson, P. B., Andersen, M. I., & Briley, M. 2000, in The Galactic Halo: From Globular Clusters to Field Stars, ed. A. Noels et al. (Liège: Inst. d'Astrophys. et Geophys.), 503        [ Links ]

Helmi, A., Navarro, J. F., Nordström, B., Holmberg, J., Abadi, M. G., & Steinmetz, M. 2006, MNRAS, 365, 1309        [ Links ]

Hertzsprung, E. 1909, ApJ, 30, 135        [ Links ]

Høg, E., et al. 2000, A & A, 355, L27        [ Links ]

Johnson, C. I., & Pilachowski, C. A. 2010, ApJ, 722, 1373        [ Links ]

Johnson, R. H., & Soderblom, D. R. 1987, AJ, 93, 864        [ Links ]

Kalnajs, A .J. 1991, in Dynamics of Disks Galaxies, ed. B. Sundelius (Göteborgs: Göteborgs Univ. & Chalmers Univ. of Technology), 323        [ Links ]

Kapteyn, J. C. 1905, Reports British Assoc. Advancement of Science, 264, 257        [ Links ]

Keller, S. C., Da Costa, G. S., & Prior, S. L. 2009, MNRAS, 394, 1045        [ Links ]

Klement, R., et al. 2009, ApJ, 698, 865        [ Links ]

Latham, D. W., Mazeh, T., Carney, B., McCrosky, R., Stefanik, R., & Davis, R. 1988, AJ, 96, 567        [ Links ]

Latham, D. W., et al. 1992, AJ, 104, 774        [ Links ]

Latham, D. W., et al. 2002, AJ, 124, 1144        [ Links ]

Lindblad, B. 1925, ApJ, 62, 191        [ Links ]

Liu, S., Nissen, P. E., Schuster, W. J., Zhao, G., Chen, Y. Q., & Liang, Y. C. 2011, A & A, submitted        [ Links ]

Luyten, W. J. 1979a, NLTT Catalog of Stars with Proper Motions Larger than Two Tenths of an Arcsecond (Minneapolis: Univ. of Minnesota Press)        [ Links ]

––––––––––. 1979b, LHS Catalogue. A Catalogue of Stars with Proper Motions Exceeding 0"5 Annually (2nd ed.; Minneapolis: Univ. of Minnesota Press)        [ Links ]

Majewski, S. R., Ostheimer, J. C., Kunkel, W. E., & Patterson, R. J. 2000, AJ, 120, 2550        [ Links ]

Mayor, M. 1972, A & A, 18, 97        [ Links ]

Meléndez, J., Schuster, W. J., Silva, J. S., Ramírez, I., Casagrande, L., & Coelho, P. 2010, A & A, 522, A98        [ Links ]

Meza, A., Navarro, J. F., Abadi, M. G., & Steinmetz, M. 2005, MNRAS, 359, 93        [ Links ]

Montes, D., López–Santiago, J., Gálvez, M. C., Fernández–Figueroa, M. J., De Castro, E., & Cornide, M. 2001, MNRAS, 328, 45        [ Links ]

Morrison, H. L., et al. 2000, AJ, 119, 2254        [ Links ]

Muñoz, R. R., et al. 2006, ApJ, 649, 201        [ Links ]

Navarro, J. F., Helmi, A., & Freeman, K. C. 2004, ApJ, 601, L43        [ Links ]

Nissen, P. E., & Schuster, W. J. 1991, A & A, 251, 457        [ Links ]

––––––––––. 2010, A & A, 511, L10        [ Links ]

––––––––––. 2011, A & A, 530, A15        [ Links ]

Nordström, B., et al. 2004, A & A, 418, 989        [ Links ]

Olsen, E. H. 1983, A & AS, 54, 55        [ Links ]

––––––––––. 1984, A & AS, 57, 443        [ Links ]

Prior, S. L., Da Costa, G. S., & Keller, S. C. 2009, ApJ, 704, 1327        [ Links ]

Proctor, R. A. 1869, R. 1995, Proc. Roy. Soc. London, 18, 169        [ Links ]

Quinn, P. J., & Goodman, J. 1986, ApJ, 309, 472        [ Links ]

Rocha–Pinto, H. J., Majewski, S. R., Skrutskie, M. F., & Crane, J. D. 2003, ApJ, 594, L115        [ Links ]

Röser, S., & Bastian, U. 1991, PPM Star Catalogue by the Astronomisches Rechen–Institut Heidelberg (Heidelberg: Spektrum Akademischer Verlag)        [ Links ]

Ryan, S. G., & Norris, J. E. 1991, AJ, 101, 1835        [ Links ]

Salim, S., & Gould, A. 2003, ApJ, 582, 1011        [ Links ]

Schuster, W. J., & Nissen, P. E. 1988, A & AS, 73, 225        [ Links ]

––––––––––. 1989, A & A, 221, 65        [ Links ]

Schuster, W. J., Beers, T. C., Michel, R., Nissen, P. E., & García, G. 2004, A & A, 422, 527        [ Links ]

Schuster, W. J., Moitinho, A., Márquez, A., Parrao, L., & Covarrubias, E. 2006, A & A, 445, 939        [ Links ]

Schuster, W. J., Moreno, E., Nissen, P. E., & Pichardo, B. 2012, A & A, 538, A21        [ Links ]

Schuster, W. J., Parrao, L., & Contreras, M. E. 1993, A & AS, 97, 951        [ Links ]

Searle, L., & Zinn, R. 1978, ApJ, 225, 357 (SZ)        [ Links ]

Sharma, S., Johnston, K. V., Majewski, S. R., Muñoz, R. R., Carlberg, J. K., & Bullock, J. 2010, ApJ, 722, 750        [ Links ]

Skuljan, J., Hearnshaw, J. B., & Cottrell, P. L. 1999, MNRAS, 308, 731        [ Links ]

Soderblom, D. R., & Mayor, M. 1993a, AJ, 105, 226        [ Links ]

––––––––––. 1993b, ApJ, 402, L5        [ Links ]

Starkenburg, E., et al. 2009, ApJ, 698, 567        [ Links ]

Tsuchiya, T., Korchagin, V. I., & Dinescu, D. I. 2004, MNRAS, 350, 1141        [ Links ]

Vivas, A. K., Jaffe, Y. L., Zinn, R., Winnick, R., Duffau, S., & Mateu, C. 2008, AJ, 136, 1645        [ Links ]

Wylie–de Boer, E., Freeman, K., & Williams, M. 2010, AJ, 139, 636        [ Links ]

Wyse, R. F. G., et al. 2006, ApJ, 639, L13        [ Links ]

Začs, L., Nissen, P. E., & Schuster, W. J. 1998, A & A, 337, 216        [ Links ]

Zinn, R., Vivas, A. K., Gallart, C., & Winnick, R. 2004, in ASP Conf. Ser. 327, Satellite and Tidal Streams, ed. F. Prada, D. Martínez–Delgado, & T. Mahoney (San Francisco: ASP), 92        [ Links ] ]]> 2003 a 591 499 2003 b 597 21 1972 2008 490 135 2011 418 1423 2010 4 13 2009 700 L78 1999 341 427 2000 142 217 1994 108 603 1998 339 831 2003 346 L11 1994 107 2240 1998 340 384 2010 721 329 1975 80 955 1970 75 978 1966 71 114 1998 115 2384 2000 119 800 2002 365 1958 118 65 1960 a 120 540 1960 b 120 563 1965 5 111 1971 83 271 1975 87 37 1977 215 812 1983 a 88 642 1983 b 88 813 1983 c 204 377 1983 d 204 391 1984 89 1358 1990 100 1159 1991 102 2028 1992 a 103 1302 1992 b 104 1482 1992 c 104 1493 1994 191 1995 a 110 1749 1995 b 110 2862 1996 a 111 1615 1996 b 112 1595 1996 c 112 2661 1998 a 116 284 1998 b 116 782 136 748 1959 119 255 ESA 1997 2005 430 165 2011 1986 91 1189 2002 40 487 2001 373 511 1961 5 61 1975 8 9 1959 4 136 2002 124 1132 1976 26 155 2000 503 2006 365 1309 1909 30 135 2000 355 L27 2010 722 1373 1987 93 864 1991 323 1905 264 257 2009 394 1045 2009 698 865 1988 96 567 1992 104 774 2002 124 1144 1925 62 191 1979 a 1979 b 2 2000 120 2550 1972 18 97 2010 522 A98 2005 359 93 2001 328 45 2000 119 2254 2006 649 201 2004 601 L43 1991 251 457 2010 511 L10 2011 530 A15 2004 418 989 1983 54 55 1984 57 443 2009 704 1327 1995 18 169 1986 309 472 2003 594 L115 1991 1991 101 1835 2003 582 1011 1988 73 225 1989 221 65 2004 422 527 2006 445 939 2012 538 A21 1993 97 951 1978 225 357 2010 722 750 1999 308 731 1993 a 105 226 1993 b 402 L5 2009 698 567 2004 350 1141 2008 136 1645 2010 139 636 2006 639 L13 1998 337 216 2004 92