Tillich, A., Heber, U. (Ulrich), 1954-, Geier, S., Hirsch, H., Maxted, P. F. L., Gänsicke, B. T. (Boris T.), Marsh, T. R., Napiwotzki, Ralf, Østensen, R. H. and Scholz, R.-D.. (2011) The Hyper-MUCHFUSS project : probing the Galactic halo with sdB stars. Astronomy & Astrophysics, Vol.527 . A137. ISSN 0004-6361

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Abstract

Context. High-velocity stars in the Galactic halo, e.g. the so-called hyper-velocity stars (HVS), are important tracers of the properties of the dark matter halo, in particular its mass. Aims. A search for the fastest stars among hot subdwarfs (sdB) in the halo is carried out to identify HVS, unbound to the Galaxy, and bound population II stars, in order to derive a lower limit to the halo mass. Methods. Based on the SDSS DR6 spectral database we selected stars with high rest-frame velocities. These radial velocity (RV) measurements were verified at several telescopes to exclude RV variable stars. Out of 88 stars observed in the follow-up campaign, 39 stars were found to have constant RVs. For twelve of them we measured a proper motion significantly different from zero and obtained spectroscopic distances from quantitative spectral analysis to construct the full 6D phase space information for a kinematical study. Results. All but one programme sdB show halo characteristics, but can be distinguished as two kinematical groups, one (G1) with the low Galactic rotation typical of halo stars and a second one (G2) with rapid retrograde motion. We also investigate the possibility that the programme stars are not genuine halo stars but ejected from the Galactic disc or bulge. The G1 objects crossed the Galactic plane in the central bulge, whereas the G2 stars did so in the outer Galactic disc. J1211+1437 (G2) is an HVS candidate, as it is unbound to the Galaxy if the standard Galactic potential is adopted. Conclusions. We conclude that in the ejection scenario, G1 stars might have been formed via the slingshot mechanism that invokes acceleration by tidal interaction of a binary with the central supermassive black hole. The G2 stars, however, would originate in the outskirts of the Galactic disc and not in the central bulge. J1211+1437 is the first unbound subdwarf B star, for which we can rule out the slingshot mechanism. Alternatively, we may assume that the stars are old population II stars and so they have to be bound. Then the kinematics of J1211+1437 set a lower limit of 2 × 1012 M⊙ to the mass of the Galactic dark matter halo.

Item Type:	Journal Article
Subjects:	Q Science > QB Astronomy
Divisions:	Faculty of Science > Physics
Library of Congress Subject Headings (LCSH):	Kinematics, Galactic halos, Stellar dynamics, Stars -- Atmospheres, Dwarf stars
Journal or Publication Title:	Astronomy & Astrophysics
Publisher:	EDP Sciences
ISSN:	0004-6361
Date:	2011
Volume:	Vol.527
Number of Pages:	11
Page Range:	A137
Identification Number:	10.1051/0004-6361/201015539
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
Funder:	Deutsche Forschungsgemeinschaft (DFG) , Seventh Framework Programme (European Commission) (FP7), Katholieke Universiteit te Leuven (1970- ), Alfred P. Sloan Foundation , National Science Foundation (U.S.) (NSF), United States. Dept. of Energy, United States. National Aeronautics and Space Administration (NASA), Japanese Monbukagakusho , Max Planck Society, Higher Education Funding Council for England (HEFCE)
Grant number:	HE1356/45-1 (DFG), HE1356/49-1 (DFG), HE1356/44-1 (DFG), HE1356/48-1 (DFG), HE1356/50-1 (DFG), 227224 (FP7), GOA/2008/04 (KUL)
References:	Allen, C., & Santillan, A. 1991, Rev. Mex. Astron. Astrofis., 22, 255 Altmann, M., Edelmann, H., & de Boer, K. S. 2004, A&A, 414, 181 Battaglia, G., Helmi, A., Morrison, H., et al. 2005, MNRAS, 364, 433 Brown, T. M., Smith, E., Ferguson, H. C., et al. 2008, ApJ, 682, 319 Brown, W. R., Geller, M. J., Kenyon, S. J., & Kurtz, M. J. 2005, ApJ, 622, L33 Brown, W. R., Geller, M. J., Kenyon, S. J., Kurtz, M. J., & Bromley, B. C. 2007, ApJ, 660, 311 Brown, W. R., Geller, M. J., & Kenyon, S. J. 2009, ApJ, 690, 1639 Carlsberg-Meridian-Catalog 2006, Copenhagen Univ. Obs., Inst. of Astr., Cambridge, UK, Real Inst. y Obs. de la Armada en San Fernando, 1304, 0 Cutri, R. M., Skrutskie, M. F., van Dyk, S., et al. 2003, 2MASS All Sky Catalog of point sources. Dehnen, W., & Binney, J. J. 1998, MNRAS, 298, 387 Dorman, B., Rood, R. T., & O’Connell, R. W. 1993, ApJ, 419, 596 Edelmann, H., Napiwotzki, R., Heber, U., Christlieb, N., & Reimers, D. 2005, ApJ, 634, L181 Eisenstein, D. J., Liebert, J., Harris, H. C., et al. 2006, ApJS, 167, 40 Evans, D. W. 1992, MNRAS, 255, 521 Finkbeiner, D. P., Padmanabhan, N., Schlegel, D. J., et al. 2004, AJ, 128, 2577 Geier, S., Hirsch, H., Tillich, A., et al. 2011a, A&A, submitted Geier, S., Maxted, P. F. L., Napiwotzki, R., et al. 2011b, A&A, 526, A39 Green, R. F., Schmidt, M., & Liebert, J. 1986, ApJS, 61, 305 Hambly, N. C., MacGillivray, H. T., Read, M. A., et al. 2001, MNRAS, 326, 1279 Han, Z., Podsiadlowski, P.,Maxted, P. F. L., & Marsh, T. R. 2003, MNRAS, 341, 669 Heber, U. 1986, A&A, 155, 33 Heber, U. 2009, ARA&A, 47, 211 Heber, U., Reid, I. N., & Werner, K. 2000, A&A, 363, 198 Heber, U., Edelmann, H., Napiwotzki, R., Altmann, M., & Scholz, R.-D. 2008, A&A, 483, L21 Hills, J. G. 1988, Nature, 331, 687 Hirsch, H. A., Heber, U., O’Toole, S. J., & Bresolin, F. 2005, A&A, 444, L61 Irrgang, A., Przybilla, N., Heber, U., Nieva, M. F., & Schuh, S. 2010, ApJ, 711, 138 Jordi, K., Grebel, E. K., & Ammon, K. 2006, A&A, 460, 339 Justham, S., Wolf, C., Podsiadlowski, P., & Han, Z. 2009, A&A, 493, 1081 Koester, D. 2009, A&A, 498, 517 Lawrence, A., Warren, S. J., Almaini, O., et al. 2007, MNRAS, 379, 1599 Lisker, T., Heber, U., Napiwotzki, R., et al. 2005, A&A, 430, 223 Marietta, E., Burrows, A., & Fryxell, B. 2000, ApJS, 128, 615 McMahon, R. G., Irwin, M. J., & Maddox, S. J. 2000, VizieR Online Data Catalog, 1267, 0 Napiwotzki, R. 2008, in Hydrogen-Deficient Stars, ed. A. Werner, & T. Rauch, ASP Conf. Ser., 391, 257 Navarro, J. F., Frenk, C. S., & White, S. D. M. 1996, ApJ, 462, 563 Navarro, J. F., Frenk, C. S., & White, S. D. M. 1997, ApJ, 490, 493 Nelemans, G., & Tauris, T. M. 1998, A&A, 335, L85 Odenkirchen, M., & Brosche, P. 1992, Astron. Nachr., 313, 69 Østensen, R. H. 2009, Communications in Asteroseismology, 159, 75 Pauli, E., Napiwotzki, R., Altmann, M., et al. 2003, A&A, 400, 877 Pauli, E., Napiwotzki, R., Heber, U., Altmann, M., & Odenkirchen, M. 2006, A&A, 447, 173 Przybilla, N., Tillich, A., Heber, U., & Scholz, R. 2010, ApJ, 718, 37 Ramspeck, M., Heber, U., & Moehler, S. 2001, A&A, 378, 907 Roeser, S., Demleitner, M., & Schilbach, E. 2010, AJ, 139, 2440 Sakamoto, T., Chiba, M., & Beers, T. C. 2003, A&A, 397, 899 Smith, M. C., Ruchti, G. R., Helmi, A., et al. 2007, MNRAS, 379, 755 Steinmetz, M., Zwitter, T., Siebert, A., et al. 2006, AJ, 132, 1645 Tillich, A., Przybilla, N., Scholz, R., & Heber, U. 2009, A&A, 507, L37 Tillich, A., Geier, S., Heber, U., et al. 2010a, Ap&SS, 117 Tillich, A., Przybilla, N., Scholz, R., & Heber, U. 2010b, A&A, 517, A36 Wang, B., & Han, Z. 2009, A&A, 508, L27 Wilkinson, M. I., & Evans, N. W. 1999, MNRAS, 310, 645 Xue, X. X., Rix, H. W., Zhao, G., et al. 2008, ApJ, 684, 1143 York, D. G., Adelman, J., Anderson, Jr., J. E., et al. 2000, AJ, 120, 1579 Page 11
URI:	http://wrap.warwick.ac.uk/id/eprint/39755

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