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Search for RR Lyrae stars in DES ultra-faint systems: Grus I, Kim 2, Phoenix II, and Grus II

Fuente: arXiv

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Detalles Bibliográficos
Autores principales:	Martínez-Vázquez, C. E., Vivas, A. K., Foucoin, M., Walker, A. R., McCarthy, M., Pace, A. B., Stringer, K. M., Santiago, B., Hounsell, R., Macri, L., Li, T. S., Bechtol, K., Riley, A. H., Kim, A. G., Simon, J. D., Drlica-Wagner, A., Nadler, E. O., Marshall, J. L., Annis, J., Avila, S., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, da Costa, L. N., De Vicente, J., Desai, S., Diehl, H. T., Doel, P., Everett, S., Frieman, J., García-Bellido, J., Gaztanaga, E., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Kuropatkin, N., Maia, M. A. G., Menanteau, F., Miller, C. J., Miquel, R., Paz-Chinchón, F., Plazas, A. A., Sanchez, E., Scarpine, V., Serrano, S., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Sobreira, F., Swanson, M. E. C., Tarle, G., Vikram, V.
Formato:	Preprint
Publicado:	2019
Materias:	Astrophysics of Galaxies Solar and Stellar Astrophysics
Acceso en línea:	Acceder al recurso
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

_version_	1866910265078972416
author	Martínez-Vázquez, C. E. Vivas, A. K. Foucoin, M. Walker, A. R. McCarthy, M. Pace, A. B. Stringer, K. M. Santiago, B. Hounsell, R. Macri, L. Li, T. S. Bechtol, K. Riley, A. H. Kim, A. G. Simon, J. D. Drlica-Wagner, A. Nadler, E. O. Marshall, J. L. Annis, J. Avila, S. Bertin, E. Brooks, D. Buckley-Geer, E. Burke, D. L. Rosell, A. Carnero Kind, M. Carrasco da Costa, L. N. De Vicente, J. Desai, S. Diehl, H. T. Doel, P. Everett, S. Frieman, J. García-Bellido, J. Gaztanaga, E. Gruen, D. Gruendl, R. A. Gschwend, J. Gutierrez, G. Hollowood, D. L. Honscheid, K. James, D. J. Kuehn, K. Kuropatkin, N. Maia, M. A. G. Menanteau, F. Miller, C. J. Miquel, R. Paz-Chinchón, F. Plazas, A. A. Sanchez, E. Scarpine, V. Serrano, S. Sevilla-Noarbe, I. Smith, M. Soares-Santos, M. Sobreira, F. Swanson, M. E. C. Tarle, G. Vikram, V.
author_facet	Martínez-Vázquez, C. E. Vivas, A. K. Foucoin, M. Walker, A. R. McCarthy, M. Pace, A. B. Stringer, K. M. Santiago, B. Hounsell, R. Macri, L. Li, T. S. Bechtol, K. Riley, A. H. Kim, A. G. Simon, J. D. Drlica-Wagner, A. Nadler, E. O. Marshall, J. L. Annis, J. Avila, S. Bertin, E. Brooks, D. Buckley-Geer, E. Burke, D. L. Rosell, A. Carnero Kind, M. Carrasco da Costa, L. N. De Vicente, J. Desai, S. Diehl, H. T. Doel, P. Everett, S. Frieman, J. García-Bellido, J. Gaztanaga, E. Gruen, D. Gruendl, R. A. Gschwend, J. Gutierrez, G. Hollowood, D. L. Honscheid, K. James, D. J. Kuehn, K. Kuropatkin, N. Maia, M. A. G. Menanteau, F. Miller, C. J. Miquel, R. Paz-Chinchón, F. Plazas, A. A. Sanchez, E. Scarpine, V. Serrano, S. Sevilla-Noarbe, I. Smith, M. Soares-Santos, M. Sobreira, F. Swanson, M. E. C. Tarle, G. Vikram, V.
contents	This work presents the first search for RR Lyrae stars (RRLs) in four of the ultra-faint systems imaged by the Dark Energy Survey (DES) using SOAR/Goodman and Blanco/DECam imagers. We have detected two RRLs in the field of Grus I, none in Kim 2, one in Phoenix II, and four in Grus II. With the detection of these stars, we accurately determine the distance moduli for these ultra-faint dwarf satellite galaxies; $μ_0$=20.51$\pm$0.10 mag (D$_{\odot}$=127$\pm$6 kpc) for Grus I and $μ_0$=20.01$\pm$0.10 mag (D$_{\odot}$=100$\pm$5 kpc) for Phoenix II. These measurements are larger than previous estimations by Koposov et al. 2015 and Bechtol et al. 2015, implying larger physical sizes; 5\% for Grus I and 33\% for Phoenix II. For Grus II, out of the four RRLs detected, one is consistent with being a member of the galactic halo (D$_\odot$=24$\pm$1 kpc, $μ_0$=16.86$\pm$0.10 mag), another is at D$_\odot$=55$\pm$2 kpc ($μ_0$=18.71$\pm$0.10 mag), which we associate with Grus II, and the two remaining at D$_\odot$=43$\pm$2 kpc ($μ_0$=18.17$\pm$0.10 mag). Moreover, the appearance of a subtle red horizontal branch in the color-magnitude diagram of Grus II at the same brightness level of the latter two RRLs, which are at the same distance and in the same region, suggests that a more metal-rich system may be located in front of Grus II. The most plausible scenario is the association of these stars with the Chenab/Orphan Stream. Finally, we performed a comprehensive and updated analysis of the number of RRLs in dwarf galaxies. This allows us to predict that the method of finding new ultra-faint dwarf galaxies by using two or more clumped RRLs will work only for systems brighter than M$_V\sim-6$ mag.
format	Preprint
id	arxiv_https___arxiv_org_abs_1909_06308
institution	arXiv
publishDate	2019
record_format	arxiv
spellingShingle	Search for RR Lyrae stars in DES ultra-faint systems: Grus I, Kim 2, Phoenix II, and Grus II Martínez-Vázquez, C. E. Vivas, A. K. Foucoin, M. Walker, A. R. McCarthy, M. Pace, A. B. Stringer, K. M. Santiago, B. Hounsell, R. Macri, L. Li, T. S. Bechtol, K. Riley, A. H. Kim, A. G. Simon, J. D. Drlica-Wagner, A. Nadler, E. O. Marshall, J. L. Annis, J. Avila, S. Bertin, E. Brooks, D. Buckley-Geer, E. Burke, D. L. Rosell, A. Carnero Kind, M. Carrasco da Costa, L. N. De Vicente, J. Desai, S. Diehl, H. T. Doel, P. Everett, S. Frieman, J. García-Bellido, J. Gaztanaga, E. Gruen, D. Gruendl, R. A. Gschwend, J. Gutierrez, G. Hollowood, D. L. Honscheid, K. James, D. J. Kuehn, K. Kuropatkin, N. Maia, M. A. G. Menanteau, F. Miller, C. J. Miquel, R. Paz-Chinchón, F. Plazas, A. A. Sanchez, E. Scarpine, V. Serrano, S. Sevilla-Noarbe, I. Smith, M. Soares-Santos, M. Sobreira, F. Swanson, M. E. C. Tarle, G. Vikram, V. Astrophysics of Galaxies Solar and Stellar Astrophysics This work presents the first search for RR Lyrae stars (RRLs) in four of the ultra-faint systems imaged by the Dark Energy Survey (DES) using SOAR/Goodman and Blanco/DECam imagers. We have detected two RRLs in the field of Grus I, none in Kim 2, one in Phoenix II, and four in Grus II. With the detection of these stars, we accurately determine the distance moduli for these ultra-faint dwarf satellite galaxies; $μ_0$=20.51$\pm$0.10 mag (D$_{\odot}$=127$\pm$6 kpc) for Grus I and $μ_0$=20.01$\pm$0.10 mag (D$_{\odot}$=100$\pm$5 kpc) for Phoenix II. These measurements are larger than previous estimations by Koposov et al. 2015 and Bechtol et al. 2015, implying larger physical sizes; 5\% for Grus I and 33\% for Phoenix II. For Grus II, out of the four RRLs detected, one is consistent with being a member of the galactic halo (D$_\odot$=24$\pm$1 kpc, $μ_0$=16.86$\pm$0.10 mag), another is at D$_\odot$=55$\pm$2 kpc ($μ_0$=18.71$\pm$0.10 mag), which we associate with Grus II, and the two remaining at D$_\odot$=43$\pm$2 kpc ($μ_0$=18.17$\pm$0.10 mag). Moreover, the appearance of a subtle red horizontal branch in the color-magnitude diagram of Grus II at the same brightness level of the latter two RRLs, which are at the same distance and in the same region, suggests that a more metal-rich system may be located in front of Grus II. The most plausible scenario is the association of these stars with the Chenab/Orphan Stream. Finally, we performed a comprehensive and updated analysis of the number of RRLs in dwarf galaxies. This allows us to predict that the method of finding new ultra-faint dwarf galaxies by using two or more clumped RRLs will work only for systems brighter than M$_V\sim-6$ mag.
title	Search for RR Lyrae stars in DES ultra-faint systems: Grus I, Kim 2, Phoenix II, and Grus II
topic	Astrophysics of Galaxies Solar and Stellar Astrophysics
url	https://arxiv.org/abs/1909.06308