Deep SOAR follow-up photometry of two Milky Way outer-halo companions discovered with Dark Energy Survey

E. Luque, B. Santiago, A. Pieres, J. L. Marshall, A. B. Pace, R. Kron, A. Drlica-Wagner, A. Queiroz, E. Balbinot, M. dal Ponte, A. Fausti Neto, L. N. da Costa, M. A.G. Maia, A. R. Walker, F. B. Abdalla, S. Allam, J. Annis, K. Bechtol, A. Benoit-Lévy, E. BertinD. Brooks, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, M. Crocce, C. Davis, P. Doel, T. F. Eifler, B. Flaugher, J. García-Bellido, D. W. Gerdes, D. Gruen, R. A. Gruendl, G. Gutierrez, K. Honscheid, D. J. James, K. Kuehn, N. Kuropatkin, R. Miquel, R. C. Nichol, A. A. Plazas, E. Sanchez, V. Scarpine, R. Schindler, I. Sevilla-Noarbe, M. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, G. Tarle, D. Thomas

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We report the discovery of a new star cluster, DES 3, in the constellation of Indus, and deeper observations of the previously identified satellite DES J0222.7-5217 (Eridanus III). DES 3 was detected as a stellar overdensity in first-year Dark Energy Survey data, and confirmed with deeper photometry from the 4.1-m Southern Astrophysical Research (SOAR) telescope. The new system was detected with a relatively high significance and appears in the DES images as a compact concentration of faint blue point sources. We determine that DES 3 is located at a heliocentric distance of ≃76.2 kpc and it is dominated by an old (≃9.8Gyr) and metal-poor ([Fe/H] ≃ -1.84) population. While the age and metallicity values of DES 3 are comparable to typical globular clusters (objects with a high stellar density, stellar mass of ~105 M and luminosity MV ~ -7.3), its half-light radius (rh ~ 6.87 pc) and luminosity (MV ~ -1.7) are more indicative of faint star cluster. Based on the angular size, DES 3, with a value of rh ~ 0'.31, is among the smallest faint star clusters known to date. Furthermore, using deeper imaging of DES J0222.7-5217 taken with the SOAR telescope, we update structural parameters and perform the first isochrone modelling. Our analysis yields the first age (≃12.6Gyr) and metallicity ([Fe/H] ≃ -2.01) estimates for this object. The half-light radius (rh ≃ 11.24 pc) and luminosity (MV ≃ -2.4) of DES J0222.7-5217 suggest that it is likely a faint star cluster. The discovery of DES 3 indicates that the census of stellar systems in the MilkyWay is still far from complete, and demonstrates the power of modern wide-field imaging surveys to improve our knowledge of the Galaxy's satellite population.

Original languageEnglish (US)
Pages (from-to)2006-2018
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume478
Issue number2
DOIs
StatePublished - Aug 1 2018
Externally publishedYes

Fingerprint

star clusters
dark energy
photometry
halos
astrophysics
luminosity
metallicity
energy
telescopes
census
stellar systems
radii
point source
constellations
globular clusters
stellar mass
point sources
metal
galaxies
modeling

Keywords

  • Galaxy: halo
  • Globular clusters: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Deep SOAR follow-up photometry of two Milky Way outer-halo companions discovered with Dark Energy Survey. / Luque, E.; Santiago, B.; Pieres, A.; Marshall, J. L.; Pace, A. B.; Kron, R.; Drlica-Wagner, A.; Queiroz, A.; Balbinot, E.; dal Ponte, M.; Fausti Neto, A.; da Costa, L. N.; Maia, M. A.G.; Walker, A. R.; Abdalla, F. B.; Allam, S.; Annis, J.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Davis, C.; Doel, P.; Eifler, T. F.; Flaugher, B.; García-Bellido, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Miquel, R.; Nichol, R. C.; Plazas, A. A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Sevilla-Noarbe, I.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.

In: Monthly Notices of the Royal Astronomical Society, Vol. 478, No. 2, 01.08.2018, p. 2006-2018.

Research output: Contribution to journalArticle

Luque, E, Santiago, B, Pieres, A, Marshall, JL, Pace, AB, Kron, R, Drlica-Wagner, A, Queiroz, A, Balbinot, E, dal Ponte, M, Fausti Neto, A, da Costa, LN, Maia, MAG, Walker, AR, Abdalla, FB, Allam, S, Annis, J, Bechtol, K, Benoit-Lévy, A, Bertin, E, Brooks, D, Carnero Rosell, A, Carrasco Kind, M, Carretero, J, Crocce, M, Davis, C, Doel, P, Eifler, TF, Flaugher, B, García-Bellido, J, Gerdes, DW, Gruen, D, Gruendl, RA, Gutierrez, G, Honscheid, K, James, DJ, Kuehn, K, Kuropatkin, N, Miquel, R, Nichol, RC, Plazas, AA, Sanchez, E, Scarpine, V, Schindler, R, Sevilla-Noarbe, I, Smith, M, Soares-Santos, M, Sobreira, F, Suchyta, E, Tarle, G & Thomas, D 2018, 'Deep SOAR follow-up photometry of two Milky Way outer-halo companions discovered with Dark Energy Survey', Monthly Notices of the Royal Astronomical Society, vol. 478, no. 2, pp. 2006-2018. https://doi.org/10.1093/mnras/sty1039
Luque, E. ; Santiago, B. ; Pieres, A. ; Marshall, J. L. ; Pace, A. B. ; Kron, R. ; Drlica-Wagner, A. ; Queiroz, A. ; Balbinot, E. ; dal Ponte, M. ; Fausti Neto, A. ; da Costa, L. N. ; Maia, M. A.G. ; Walker, A. R. ; Abdalla, F. B. ; Allam, S. ; Annis, J. ; Bechtol, K. ; Benoit-Lévy, A. ; Bertin, E. ; Brooks, D. ; Carnero Rosell, A. ; Carrasco Kind, M. ; Carretero, J. ; Crocce, M. ; Davis, C. ; Doel, P. ; Eifler, T. F. ; Flaugher, B. ; García-Bellido, J. ; Gerdes, D. W. ; Gruen, D. ; Gruendl, R. A. ; Gutierrez, G. ; Honscheid, K. ; James, D. J. ; Kuehn, K. ; Kuropatkin, N. ; Miquel, R. ; Nichol, R. C. ; Plazas, A. A. ; Sanchez, E. ; Scarpine, V. ; Schindler, R. ; Sevilla-Noarbe, I. ; Smith, M. ; Soares-Santos, M. ; Sobreira, F. ; Suchyta, E. ; Tarle, G. ; Thomas, D. / Deep SOAR follow-up photometry of two Milky Way outer-halo companions discovered with Dark Energy Survey. In: Monthly Notices of the Royal Astronomical Society. 2018 ; Vol. 478, No. 2. pp. 2006-2018.
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abstract = "We report the discovery of a new star cluster, DES 3, in the constellation of Indus, and deeper observations of the previously identified satellite DES J0222.7-5217 (Eridanus III). DES 3 was detected as a stellar overdensity in first-year Dark Energy Survey data, and confirmed with deeper photometry from the 4.1-m Southern Astrophysical Research (SOAR) telescope. The new system was detected with a relatively high significance and appears in the DES images as a compact concentration of faint blue point sources. We determine that DES 3 is located at a heliocentric distance of ≃76.2 kpc and it is dominated by an old (≃9.8Gyr) and metal-poor ([Fe/H] ≃ -1.84) population. While the age and metallicity values of DES 3 are comparable to typical globular clusters (objects with a high stellar density, stellar mass of ~105 M⊙ and luminosity MV ~ -7.3), its half-light radius (rh ~ 6.87 pc) and luminosity (MV ~ -1.7) are more indicative of faint star cluster. Based on the angular size, DES 3, with a value of rh ~ 0'.31, is among the smallest faint star clusters known to date. Furthermore, using deeper imaging of DES J0222.7-5217 taken with the SOAR telescope, we update structural parameters and perform the first isochrone modelling. Our analysis yields the first age (≃12.6Gyr) and metallicity ([Fe/H] ≃ -2.01) estimates for this object. The half-light radius (rh ≃ 11.24 pc) and luminosity (MV ≃ -2.4) of DES J0222.7-5217 suggest that it is likely a faint star cluster. The discovery of DES 3 indicates that the census of stellar systems in the MilkyWay is still far from complete, and demonstrates the power of modern wide-field imaging surveys to improve our knowledge of the Galaxy's satellite population.",
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TY - JOUR

T1 - Deep SOAR follow-up photometry of two Milky Way outer-halo companions discovered with Dark Energy Survey

AU - Luque, E.

AU - Santiago, B.

AU - Pieres, A.

AU - Marshall, J. L.

AU - Pace, A. B.

AU - Kron, R.

AU - Drlica-Wagner, A.

AU - Queiroz, A.

AU - Balbinot, E.

AU - dal Ponte, M.

AU - Fausti Neto, A.

AU - da Costa, L. N.

AU - Maia, M. A.G.

AU - Walker, A. R.

AU - Abdalla, F. B.

AU - Allam, S.

AU - Annis, J.

AU - Bechtol, K.

AU - Benoit-Lévy, A.

AU - Bertin, E.

AU - Brooks, D.

AU - Carnero Rosell, A.

AU - Carrasco Kind, M.

AU - Carretero, J.

AU - Crocce, M.

AU - Davis, C.

AU - Doel, P.

AU - Eifler, T. F.

AU - Flaugher, B.

AU - García-Bellido, J.

AU - Gerdes, D. W.

AU - Gruen, D.

AU - Gruendl, R. A.

AU - Gutierrez, G.

AU - Honscheid, K.

AU - James, D. J.

AU - Kuehn, K.

AU - Kuropatkin, N.

AU - Miquel, R.

AU - Nichol, R. C.

AU - Plazas, A. A.

AU - Sanchez, E.

AU - Scarpine, V.

AU - Schindler, R.

AU - Sevilla-Noarbe, I.

AU - Smith, M.

AU - Soares-Santos, M.

AU - Sobreira, F.

AU - Suchyta, E.

AU - Tarle, G.

AU - Thomas, D.

PY - 2018/8/1

Y1 - 2018/8/1

N2 - We report the discovery of a new star cluster, DES 3, in the constellation of Indus, and deeper observations of the previously identified satellite DES J0222.7-5217 (Eridanus III). DES 3 was detected as a stellar overdensity in first-year Dark Energy Survey data, and confirmed with deeper photometry from the 4.1-m Southern Astrophysical Research (SOAR) telescope. The new system was detected with a relatively high significance and appears in the DES images as a compact concentration of faint blue point sources. We determine that DES 3 is located at a heliocentric distance of ≃76.2 kpc and it is dominated by an old (≃9.8Gyr) and metal-poor ([Fe/H] ≃ -1.84) population. While the age and metallicity values of DES 3 are comparable to typical globular clusters (objects with a high stellar density, stellar mass of ~105 M⊙ and luminosity MV ~ -7.3), its half-light radius (rh ~ 6.87 pc) and luminosity (MV ~ -1.7) are more indicative of faint star cluster. Based on the angular size, DES 3, with a value of rh ~ 0'.31, is among the smallest faint star clusters known to date. Furthermore, using deeper imaging of DES J0222.7-5217 taken with the SOAR telescope, we update structural parameters and perform the first isochrone modelling. Our analysis yields the first age (≃12.6Gyr) and metallicity ([Fe/H] ≃ -2.01) estimates for this object. The half-light radius (rh ≃ 11.24 pc) and luminosity (MV ≃ -2.4) of DES J0222.7-5217 suggest that it is likely a faint star cluster. The discovery of DES 3 indicates that the census of stellar systems in the MilkyWay is still far from complete, and demonstrates the power of modern wide-field imaging surveys to improve our knowledge of the Galaxy's satellite population.

AB - We report the discovery of a new star cluster, DES 3, in the constellation of Indus, and deeper observations of the previously identified satellite DES J0222.7-5217 (Eridanus III). DES 3 was detected as a stellar overdensity in first-year Dark Energy Survey data, and confirmed with deeper photometry from the 4.1-m Southern Astrophysical Research (SOAR) telescope. The new system was detected with a relatively high significance and appears in the DES images as a compact concentration of faint blue point sources. We determine that DES 3 is located at a heliocentric distance of ≃76.2 kpc and it is dominated by an old (≃9.8Gyr) and metal-poor ([Fe/H] ≃ -1.84) population. While the age and metallicity values of DES 3 are comparable to typical globular clusters (objects with a high stellar density, stellar mass of ~105 M⊙ and luminosity MV ~ -7.3), its half-light radius (rh ~ 6.87 pc) and luminosity (MV ~ -1.7) are more indicative of faint star cluster. Based on the angular size, DES 3, with a value of rh ~ 0'.31, is among the smallest faint star clusters known to date. Furthermore, using deeper imaging of DES J0222.7-5217 taken with the SOAR telescope, we update structural parameters and perform the first isochrone modelling. Our analysis yields the first age (≃12.6Gyr) and metallicity ([Fe/H] ≃ -2.01) estimates for this object. The half-light radius (rh ≃ 11.24 pc) and luminosity (MV ≃ -2.4) of DES J0222.7-5217 suggest that it is likely a faint star cluster. The discovery of DES 3 indicates that the census of stellar systems in the MilkyWay is still far from complete, and demonstrates the power of modern wide-field imaging surveys to improve our knowledge of the Galaxy's satellite population.

KW - Galaxy: halo

KW - Globular clusters: general

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