DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY

T. S. Li; E. Balbinot; N. Mondrik; J. L. Marshall; B. Yanny; K. Bechtol; A. Drlica-Wagner; D. Oscar; B. Santiago; J. D. Simon; A. K. Vivas; A. R. Walker; M. Y. Wang; T. M.C. Abbott; F. B. Abdalla; A. Benoit-Lévy; G. M. Bernstein; E. Bertin; D. Brooks; D. L. Burke; A. Carnero Rosell; M. Carrasco Kind; J. Carretero; L. N.Da Costa; D. L. Depoy; S. Desai; H. T. Diehl; P. Doel; J. Estrada; D. A. Finley; B. Flaugher; J. Frieman; D. Gruen; R. A. Gruendl; G. Gutierrez; K. Honscheid; D. J. James; K. Kuehn; N. Kuropatkin; O. Lahav; M. A.G. Maia; M. March; P. Martini; R. Ogando; A. A. Plazas; K. Reil; A. K. Romer; A. Roodman; E. Sanchez; V. Scarpine; M. Schubnell; I. Sevilla-Noarbe; R. C. Smith; M. Soares-Santos; F. Sobreira; E. Suchyta; M. E.C. Swanson; G. Tarle; D. Tucker; Y. Zhang

doi:10.3847/0004-637X/817/2/135

DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY

T. S. Li, E. Balbinot, N. Mondrik, J. L. Marshall, B. Yanny, K. Bechtol, A. Drlica-Wagner, D. Oscar, B. Santiago, J. D. Simon, A. K. Vivas, A. R. Walker, M. Y. Wang, T. M.C. Abbott, F. B. Abdalla, A. Benoit-Lévy, G. M. Bernstein, E. Bertin, D. Brooks, D. L. BurkeA. Carnero Rosell, M. Carrasco Kind, J. Carretero, L. N.Da Costa, D. L. Depoy, S. Desai, H. T. Diehl, P. Doel, J. Estrada, D. A. Finley, B. Flaugher, J. Frieman, D. Gruen, R. A. Gruendl, G. Gutierrez, K. Honscheid, D. J. James, K. Kuehn, N. Kuropatkin, O. Lahav, M. A.G. Maia, M. March, P. Martini, R. Ogando, A. A. Plazas, K. Reil, A. K. Romer, A. Roodman, E. Sanchez, V. Scarpine, M. Schubnell, I. Sevilla-Noarbe, R. C. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E.C. Swanson, G. Tarle, D. Tucker, Y. Zhang

Research output: Contribution to journal › Review article › Research › peer-review

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Abstract

We report the discovery of an excess of main-sequence turnoff stars in the direction of the constellations of Eridanus and Phoenix from the first-year data of the Dark Energy Survey (DES). The Eridanus-Phoenix (EriPhe) overdensity is centered around l ∼ 285° and b ∼ -60° and spans at least 30° in longitude and 10° in latitude. The Poisson significance of the detection is at least 9s. The stellar population in the overdense region is similar in brightness and color to that of the nearby globular cluster NGC 1261, indicating that the heliocentric distance of EriPhe is about d ∼ 16 kpc. The extent of EriPhe in projection is therefore at least ∼4 kpc by ∼3 kpc. On the sky, this overdensity is located between NGC 1261 and a new stellar stream discovered by DES at a similar heliocentric distance, the so-called Phoenix Stream. Given their similar distance and proximity to each other, it is possible that these three structures may be kinematically associated. Alternatively, the EriPhe overdensity is morphologically similar to the Virgo overdensity and the Hercules-Aquila cloud, which also lie at a similar Galactocentric distance. These three overdensities lie along a polar plane separated by ∼120° and may share a common origin. Spectroscopic follow-up observations of the stars in EriPhe are required to fully understand the nature of this overdensity.

Original language	English
Article number	135
Journal	Astrophysical Journal
Volume	817
Issue number	2
DOIs	https://doi.org/10.3847/0004-637X/817/2/135
Publication status	Published - 1 Feb 2016

Keywords

galaxy: formation
galaxy: halo
galaxy: structure
local group

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10.3847/0004-637X/817/2/135

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Li, T. S., Balbinot, E., Mondrik, N., Marshall, J. L., Yanny, B., Bechtol, K., Drlica-Wagner, A., Oscar, D., Santiago, B., Simon, J. D., Vivas, A. K., Walker, A. R., Wang, M. Y., Abbott, T. M. C., Abdalla, F. B., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Brooks, D., ... Zhang, Y. (2016). DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY. Astrophysical Journal, 817(2), [135]. https://doi.org/10.3847/0004-637X/817/2/135

Li, T. S. ; Balbinot, E. ; Mondrik, N. ; Marshall, J. L. ; Yanny, B. ; Bechtol, K. ; Drlica-Wagner, A. ; Oscar, D. ; Santiago, B. ; Simon, J. D. ; Vivas, A. K. ; Walker, A. R. ; Wang, M. Y. ; Abbott, T. M.C. ; Abdalla, F. B. ; Benoit-Lévy, A. ; Bernstein, G. M. ; Bertin, E. ; Brooks, D. ; Burke, D. L. ; Rosell, A. Carnero ; Kind, M. Carrasco ; Carretero, J. ; Costa, L. N.Da ; Depoy, D. L. ; Desai, S. ; Diehl, H. T. ; Doel, P. ; Estrada, J. ; Finley, D. A. ; Flaugher, B. ; Frieman, J. ; Gruen, D. ; Gruendl, R. A. ; Gutierrez, G. ; Honscheid, K. ; James, D. J. ; Kuehn, K. ; Kuropatkin, N. ; Lahav, O. ; Maia, M. A.G. ; March, M. ; Martini, P. ; Ogando, R. ; Plazas, A. A. ; Reil, K. ; Romer, A. K. ; Roodman, A. ; 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. ; Zhang, Y. / DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY. In: Astrophysical Journal. 2016 ; Vol. 817, No. 2.

@article{7ddc9bde22344df18c406c569e16ab02,

title = "DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY",

abstract = "We report the discovery of an excess of main-sequence turnoff stars in the direction of the constellations of Eridanus and Phoenix from the first-year data of the Dark Energy Survey (DES). The Eridanus-Phoenix (EriPhe) overdensity is centered around l ∼ 285° and b ∼ -60° and spans at least 30° in longitude and 10° in latitude. The Poisson significance of the detection is at least 9s. The stellar population in the overdense region is similar in brightness and color to that of the nearby globular cluster NGC 1261, indicating that the heliocentric distance of EriPhe is about d ∼ 16 kpc. The extent of EriPhe in projection is therefore at least ∼4 kpc by ∼3 kpc. On the sky, this overdensity is located between NGC 1261 and a new stellar stream discovered by DES at a similar heliocentric distance, the so-called Phoenix Stream. Given their similar distance and proximity to each other, it is possible that these three structures may be kinematically associated. Alternatively, the EriPhe overdensity is morphologically similar to the Virgo overdensity and the Hercules-Aquila cloud, which also lie at a similar Galactocentric distance. These three overdensities lie along a polar plane separated by ∼120° and may share a common origin. Spectroscopic follow-up observations of the stars in EriPhe are required to fully understand the nature of this overdensity.",

keywords = "galaxy: formation, galaxy: halo, galaxy: structure, local group",

author = "Li, {T. S.} and E. Balbinot and N. Mondrik and Marshall, {J. L.} and B. Yanny and K. Bechtol and A. Drlica-Wagner and D. Oscar and B. Santiago and Simon, {J. D.} and Vivas, {A. K.} and Walker, {A. R.} and Wang, {M. Y.} and Abbott, {T. M.C.} and Abdalla, {F. B.} and A. Benoit-L{\'e}vy and Bernstein, {G. M.} and E. Bertin and D. Brooks and Burke, {D. L.} and Rosell, {A. Carnero} and Kind, {M. Carrasco} and J. Carretero and Costa, {L. N.Da} and Depoy, {D. L.} and S. Desai and Diehl, {H. T.} and P. Doel and J. Estrada and Finley, {D. A.} and B. Flaugher and J. Frieman and D. Gruen and Gruendl, {R. A.} and G. Gutierrez and K. Honscheid and James, {D. J.} and K. Kuehn and N. Kuropatkin and O. Lahav and Maia, {M. A.G.} and M. March and P. Martini and R. Ogando and Plazas, {A. A.} and K. Reil and Romer, {A. K.} and A. Roodman and E. Sanchez and V. Scarpine and M. Schubnell and I. Sevilla-Noarbe and Smith, {R. C.} and M. Soares-Santos and F. Sobreira and E. Suchyta and Swanson, {M. E.C.} and G. Tarle and D. Tucker and Y. Zhang",

year = "2016",

month = feb,

day = "1",

doi = "10.3847/0004-637X/817/2/135",

language = "English",

volume = "817",

journal = "Astrophysical Journal",

issn = "0004-637X",

number = "2",

}

Li, TS, Balbinot, E, Mondrik, N, Marshall, JL, Yanny, B, Bechtol, K, Drlica-Wagner, A, Oscar, D, Santiago, B, Simon, JD, Vivas, AK, Walker, AR, Wang, MY, Abbott, TMC, Abdalla, FB, Benoit-Lévy, A, Bernstein, GM, Bertin, E, Brooks, D, Burke, DL, Rosell, AC, Kind, MC, Carretero, J, Costa, LND, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Estrada, J, Finley, DA, Flaugher, B, Frieman, J, Gruen, D, Gruendl, RA, Gutierrez, G, Honscheid, K, James, DJ, Kuehn, K, Kuropatkin, N, Lahav, O, Maia, MAG, March, M, Martini, P, Ogando, R, Plazas, AA, Reil, K, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Tucker, D & Zhang, Y 2016, 'DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY', Astrophysical Journal, vol. 817, no. 2, 135. https://doi.org/10.3847/0004-637X/817/2/135

DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY. / Li, T. S.; Balbinot, E.; Mondrik, N.; Marshall, J. L.; Yanny, B.; Bechtol, K.; Drlica-Wagner, A.; Oscar, D.; Santiago, B.; Simon, J. D.; Vivas, A. K.; Walker, A. R.; Wang, M. Y.; Abbott, T. M.C.; Abdalla, F. B.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Costa, L. N.Da; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Finley, D. A.; Flaugher, B.; Frieman, J.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A.G.; March, M.; Martini, P.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; 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.; Zhang, Y.

In: Astrophysical Journal, Vol. 817, No. 2, 135, 01.02.2016.

Research output: Contribution to journal › Review article › Research › peer-review

TY - JOUR

T1 - DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY

AU - Li, T. S.

AU - Balbinot, E.

AU - Mondrik, N.

AU - Marshall, J. L.

AU - Yanny, B.

AU - Bechtol, K.

AU - Drlica-Wagner, A.

AU - Oscar, D.

AU - Santiago, B.

AU - Simon, J. D.

AU - Vivas, A. K.

AU - Walker, A. R.

AU - Wang, M. Y.

AU - Abbott, T. M.C.

AU - Abdalla, F. B.

AU - Benoit-Lévy, A.

AU - Bernstein, G. M.

AU - Bertin, E.

AU - Brooks, D.

AU - Burke, D. L.

AU - Rosell, A. Carnero

AU - Kind, M. Carrasco

AU - Carretero, J.

AU - Costa, L. N.Da

AU - Depoy, D. L.

AU - Desai, S.

AU - Diehl, H. T.

AU - Doel, P.

AU - Estrada, J.

AU - Finley, D. A.

AU - Flaugher, B.

AU - Frieman, J.

AU - Gruen, D.

AU - Gruendl, R. A.

AU - Gutierrez, G.

AU - Honscheid, K.

AU - James, D. J.

AU - Kuehn, K.

AU - Kuropatkin, N.

AU - Lahav, O.

AU - Maia, M. A.G.

AU - March, M.

AU - Martini, P.

AU - Ogando, R.

AU - Plazas, A. A.

AU - Reil, K.

AU - Romer, A. K.

AU - Roodman, A.

AU - Sanchez, E.

AU - Scarpine, V.

AU - Schubnell, M.

AU - Sevilla-Noarbe, I.

AU - Smith, R. C.

AU - Soares-Santos, M.

AU - Sobreira, F.

AU - Suchyta, E.

AU - Swanson, M. E.C.

AU - Tarle, G.

AU - Tucker, D.

AU - Zhang, Y.

PY - 2016/2/1

Y1 - 2016/2/1

N2 - We report the discovery of an excess of main-sequence turnoff stars in the direction of the constellations of Eridanus and Phoenix from the first-year data of the Dark Energy Survey (DES). The Eridanus-Phoenix (EriPhe) overdensity is centered around l ∼ 285° and b ∼ -60° and spans at least 30° in longitude and 10° in latitude. The Poisson significance of the detection is at least 9s. The stellar population in the overdense region is similar in brightness and color to that of the nearby globular cluster NGC 1261, indicating that the heliocentric distance of EriPhe is about d ∼ 16 kpc. The extent of EriPhe in projection is therefore at least ∼4 kpc by ∼3 kpc. On the sky, this overdensity is located between NGC 1261 and a new stellar stream discovered by DES at a similar heliocentric distance, the so-called Phoenix Stream. Given their similar distance and proximity to each other, it is possible that these three structures may be kinematically associated. Alternatively, the EriPhe overdensity is morphologically similar to the Virgo overdensity and the Hercules-Aquila cloud, which also lie at a similar Galactocentric distance. These three overdensities lie along a polar plane separated by ∼120° and may share a common origin. Spectroscopic follow-up observations of the stars in EriPhe are required to fully understand the nature of this overdensity.

AB - We report the discovery of an excess of main-sequence turnoff stars in the direction of the constellations of Eridanus and Phoenix from the first-year data of the Dark Energy Survey (DES). The Eridanus-Phoenix (EriPhe) overdensity is centered around l ∼ 285° and b ∼ -60° and spans at least 30° in longitude and 10° in latitude. The Poisson significance of the detection is at least 9s. The stellar population in the overdense region is similar in brightness and color to that of the nearby globular cluster NGC 1261, indicating that the heliocentric distance of EriPhe is about d ∼ 16 kpc. The extent of EriPhe in projection is therefore at least ∼4 kpc by ∼3 kpc. On the sky, this overdensity is located between NGC 1261 and a new stellar stream discovered by DES at a similar heliocentric distance, the so-called Phoenix Stream. Given their similar distance and proximity to each other, it is possible that these three structures may be kinematically associated. Alternatively, the EriPhe overdensity is morphologically similar to the Virgo overdensity and the Hercules-Aquila cloud, which also lie at a similar Galactocentric distance. These three overdensities lie along a polar plane separated by ∼120° and may share a common origin. Spectroscopic follow-up observations of the stars in EriPhe are required to fully understand the nature of this overdensity.

KW - galaxy: formation

KW - galaxy: halo

KW - galaxy: structure

KW - local group

U2 - 10.3847/0004-637X/817/2/135

DO - 10.3847/0004-637X/817/2/135

M3 - Review article

VL - 817

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 135

ER -

DISCOVERY of A STELLAR OVERDENSITY in ERIDANUS-PHOENIX in the DARK ENERGY SURVEY

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