The Dark Energy Survey view of the Sagittarius stream: discovery of two faint stellar system candidates

Luque, E and Pieres, A and Santiago, B and Yanny, B and Vivas, A K and Queiroz, A and Drlica-Wagner, A and Morganson, E and Balbinot, E and Marshall, J L and Li, T S and Neto, A F and da Costa, L N and Maia, M A G and Bechtol, K and Kim, A G and Bernstein, G M and Dodelson, S and Whiteway, L and Diehl, H T and Finley, D A and Abbott, T and Abdalla, F B and Allam, S and Annis, J and Benoit-Lévy, A and Bertin, E and Brooks, D and Burke, D L and Rosell, A C and Kind, M C and Carretero, J and Cunha, C E and D'Andrea, C B and Desai, Shantanu and Doel, P and Evrard, A E and Flaugher, B and Fosalba, P and Gerdes, D W and Goldstein, D A and Gruen, D and Gruendl, R A and Gutierrez, G and James, D J and Kuehn, K and Kuropatkin, N and Lahav, O and Martini, P and Miquel, R and Nord, B and Ogando, R and Plazas, A A and Romer, A K and Sanchez, E and Scarpine, V and Schubnell, M and Sevilla-Noarbe, I and Smith, R C and Soares-Santos, M and Sobreira, F and Suchyta, E and Swanson, M E C and Tarle, G and Thomas, D and Walker, A R (2017) The Dark Energy Survey view of the Sagittarius stream: discovery of two faint stellar system candidates. Monthly Notices of the Royal Astronomical Society, 468 (1). pp. 97-108. ISSN 0035-8711

Preview

Text (arXiv copy)
1608.04033.pdf - Accepted Version
Download (606kB) | Preview

Abstract

We report the discovery of two new candidate stellar systems in the constellation of Cetus using the data from the first two years of the Dark E nergy Survey (DES). The objects, DES J0111-1341 and DES J0225+ 0304, are located at a heliocentric distance of -25 kpc and appear to have old and metal-poor populations. Their distances to the Sagittarius orbital plane, -1.73 kpc (DES J0111-1341) and -0.50 kpc (DES J0225+ 0304), indicate that they are possibly associated with the Sagittarius dwarf stream. The half-light radius (r(h) similar or equal to 4.55 pc) and luminosity (MV similar or equal to + 0.3) of DES J0111-1341 are consistent with it being an ultrafaint stellar cluster, while the half-light radius (rh similar or equal to 18.55 pc) and luminosity (MV similar or equal to -1.1) of DES J0225+ 0304 place it in an ambiguous region of size-luminosity space between stellar clusters and dwarf galaxies. Determinations of the characteristic parameters of the Sagittarius stream, metallicity spread (-2.18 <= [ Fe/ H] <= -0.95) and distance gradient (23 kpc <= D-circle dot <= 29 kpc), within the DES footprint in the Southern hemisphere, using the same DES data, also indicate a possible association between these systems. If these objects are confirmed through spectroscopic follow-up to be gravitationally bound systems and to share a Galactic trajectory with the Sagittarius stream, DES J0111-1341 and DES J0225+ 0304 would be the first ultrafaint stellar systems associated with the Sagittarius stream. Furthermore, DES J0225+ 0304 would also be the first confirmed case of an ultrafaint satellite of a satellite.

[error in script]

IITH Creators: