Bibcode
Pieres, A.; Santiago, B. X.; Drlica-Wagner, A.; Bechtol, K.; Marel, R. P. van der; Besla, G.; Martin, N. F.; Belokurov, V.; Gallart, C.; Martinez-Delgado, D.; Marshall, J.; Nöel, N. E. D.; Majewski, S. R.; Cioni, M.-R. L.; Li, T. S.; Hartley, W.; Luque, E.; Conn, B. C.; Walker, A. R.; Balbinot, E.; Stringfellow, G. S.; Olsen, K. A. G.; Nidever, D.; da Costa, L. N.; Ogando, R.; Maia, M.; Neto, A. Fausti; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; Desai, S.; Diehl, H. T.; Doel, P.; Flaugher, B.; Fosalba, P.; García-Bellido, J.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D.; Kuehn, K.; Kuropatkin, N.; Menanteau, F.; Miquel, R.; Plazas, A. A.; Romer, A. K.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Tucker, D. L.; Wester, W.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 468, Issue 2, p.1349-1360
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6
2017
Citations
48
Refereed citations
44
Description
We report the discovery of a stellar overdensity 8° north of the
centre of the Small Magellanic Cloud (SMC; Small Magellanic Cloud
Northern Over-Density; SMCNOD), using data from the first 2 yr of the
Dark Energy Survey (DES) and the first year of the MAGellanic SatelLITEs
Survey (MagLiteS). The SMCNOD is indistinguishable in age, metallicity
and distance from the nearby SMC stars, being primarily composed of
intermediate-age stars (6 Gyr, Z=0.001), with a small fraction of young
stars (1 Gyr, Z=0.01). The SMCNOD has an elongated shape with an
ellipticity of 0.6 and a size of ∼ 6° × 2°. It has an
absolute magnitude of MV ≅ -7.7, rh = 2.1
kpc, and μV(r < rh) = 31.2 mag
arcsec-2. We estimate a stellar mass of ∼105
M⊙, following a Kroupa mass function. The SMCNOD was
probably removed from the SMC disc by tidal stripping, since it is
located near the head of the Magellanic Stream, and the literature
indicates likely recent Large Magellanic Cloud-SMC encounters. This
scenario is supported by the lack of significant H I gas. Other
potential scenarios for the SMCNOD origin are a transient overdensity
within the SMC tidal radius or a primordial SMC satellite in advanced
stage of disruption.
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Galaxy formation and evolution is a fundamental Astrophysical problem. Its study requires “travelling back in time”, for which there are two complementary approaches. One is to analyse galaxy properties as a function of red-shift. Our team focuses on the other approach, called “Galactic Archaeology”. It is based on the determination of galaxy
Matteo
Monelli