Hydra II: a faint and compact milky way dwarf galaxy found in the survey of the magellanic stellar history

Nicolas F. Martin; David L. Nidever; Gurtina Besla; Knut Olsen; Alistair R. Walker; A. Katherina Vivas; Robert A. Gruendl; Catherine C. Kaleida; Ricardo R. Muñoz; Robert D. Blum; Abhijit Saha; Blair C. Conn; Eric F. Bell; You Hua Chu; M-R.L. Cioni; Thomas J. L. De Boer; Carme Gallart; Shoko Jin; Andrea Kunder; Steven R. Majewski; David Martinez-Delgado; Antonela Monachesi; Matteo Monelli; Lara Monteagudo; Noelia E.D. Noël; Edward W. Olszewski; Guy S. Stringfellow; Roeland P. Van Der Marel; Dennis Zaritsky

doi:10.1088/2041-8205/804/1/L5

Hydra II: a faint and compact milky way dwarf galaxy found in the survey of the magellanic stellar history

Nicolas F. Martin
, David L. Nidever
, Gurtina Besla
, Knut Olsen
, Alistair R. Walker
, A. Katherina Vivas
, Robert A. Gruendl
, Catherine C. Kaleida
, Ricardo R. Muñoz
, Robert D. Blum
, Abhijit Saha
, Blair C. Conn
, Eric F. Bell
, You Hua Chu
, M-R.L. Cioni
, Thomas J. L. De Boer
, Carme Gallart
, Shoko Jin
, Andrea Kunder
, Steven R. Majewski

David Martinez-Delgado, Antonela Monachesi, Matteo Monelli, Lara Monteagudo, Noelia E.D. Noël, Edward W. Olszewski, Guy S. Stringfellow, Roeland P. Van Der Marel, Dennis Zaritsky

Centre for Astrophysics Research (CAR)

Research output: Contribution to journal › Article › peer-review

143 Citations (Scopus)

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Abstract

We present the discovery of a new dwarf galaxy, Hydra II, found serendipitously within the data from the ongoing Survey of the Magellanic Stellar History conducted with the Dark Energy Camera on the Blanco 4 m Telescope. The new satellite is compact (r_h = 68 ± 11 pc) and faint (M_V = -4.8 ± 0.3), but well within the realm of dwarf galaxies. The stellar distribution of Hydra II in the color-magnitude diagram is well-described by a metal-poor ([Fe/H] = -2.2) and old (13 Gyr) isochrone and shows a distinct blue horizontal branch, some possible red clump stars, and faint stars that are suggestive of blue stragglers. At a heliocentric distance of 134 ± 10 kpc, Hydra II is located in a region of the Galactic halo that models have suggested may host material from the leading arm of the Magellanic Stream. A comparison with N-body simulations hints that the new dwarf galaxy could be or could have been a satellite of the Magellanic Clouds.

Original language	English
Article number	L5
Journal	Astrophysical Journal Letters
Volume	804
Issue number	1
Early online date	23 Apr 2015
DOIs	https://doi.org/10.1088/2041-8205/804/1/L5
Publication status	Published - 1 May 2015

Keywords

galaxies: individual (Hydra II)
Local Group
Magellanic Clouds

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10.1088/2041-8205/804/1/L5

907070Accepted author manuscript, 698 KB

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Martin, N. F., Nidever, D. L., Besla, G., Olsen, K., Walker, A. R., Vivas, A. K., Gruendl, R. A., Kaleida, C. C., Muñoz, R. R., Blum, R. D., Saha, A., Conn, B. C., Bell, E. F., Chu, Y. H., Cioni, M.-RL., De Boer, T. J. L., Gallart, C., Jin, S., Kunder, A., ... Zaritsky, D. (2015). Hydra II: a faint and compact milky way dwarf galaxy found in the survey of the magellanic stellar history. Astrophysical Journal Letters, 804(1), Article L5. https://doi.org/10.1088/2041-8205/804/1/L5

@article{0a45ea27a57f4abf860ff4054bafb4df,

title = "Hydra II: a faint and compact milky way dwarf galaxy found in the survey of the magellanic stellar history",

abstract = "We present the discovery of a new dwarf galaxy, Hydra II, found serendipitously within the data from the ongoing Survey of the Magellanic Stellar History conducted with the Dark Energy Camera on the Blanco 4 m Telescope. The new satellite is compact (r\_h = 68 ± 11 pc) and faint (M\_V = -4.8 ± 0.3), but well within the realm of dwarf galaxies. The stellar distribution of Hydra II in the color-magnitude diagram is well-described by a metal-poor ([Fe/H] = -2.2) and old (13 Gyr) isochrone and shows a distinct blue horizontal branch, some possible red clump stars, and faint stars that are suggestive of blue stragglers. At a heliocentric distance of 134 ± 10 kpc, Hydra II is located in a region of the Galactic halo that models have suggested may host material from the leading arm of the Magellanic Stream. A comparison with N-body simulations hints that the new dwarf galaxy could be or could have been a satellite of the Magellanic Clouds.",

keywords = "galaxies: individual (Hydra II), Local Group, Magellanic Clouds",

author = "Martin, \{Nicolas F.\} and Nidever, \{David L.\} and Gurtina Besla and Knut Olsen and Walker, \{Alistair R.\} and Vivas, \{A. Katherina\} and Gruendl, \{Robert A.\} and Kaleida, \{Catherine C.\} and Mu{\~n}oz, \{Ricardo R.\} and Blum, \{Robert D.\} and Abhijit Saha and Conn, \{Blair C.\} and Bell, \{Eric F.\} and Chu, \{You Hua\} and M-R.L. Cioni and \{De Boer\}, \{Thomas J. L.\} and Carme Gallart and Shoko Jin and Andrea Kunder and Majewski, \{Steven R.\} and David Martinez-Delgado and Antonela Monachesi and Matteo Monelli and Lara Monteagudo and No{\"e}l, \{Noelia E.D.\} and Olszewski, \{Edward W.\} and Stringfellow, \{Guy S.\} and \{Van Der Marel\}, \{Roeland P.\} and Dennis Zaritsky",

note = "Date of Acceptance: 31/03/2015",

year = "2015",

month = may,

day = "1",

doi = "10.1088/2041-8205/804/1/L5",

language = "English",

volume = "804",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

publisher = "American Astronomical Society",

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Martin, NF, Nidever, DL, Besla, G, Olsen, K, Walker, AR, Vivas, AK, Gruendl, RA, Kaleida, CC, Muñoz, RR, Blum, RD, Saha, A, Conn, BC, Bell, EF, Chu, YH, Cioni, M-RL, De Boer, TJL, Gallart, C, Jin, S, Kunder, A, Majewski, SR, Martinez-Delgado, D, Monachesi, A, Monelli, M, Monteagudo, L, Noël, NED, Olszewski, EW, Stringfellow, GS, Van Der Marel, RP & Zaritsky, D 2015, 'Hydra II: a faint and compact milky way dwarf galaxy found in the survey of the magellanic stellar history', Astrophysical Journal Letters, vol. 804, no. 1, L5. https://doi.org/10.1088/2041-8205/804/1/L5

TY - JOUR

T1 - Hydra II: a faint and compact milky way dwarf galaxy found in the survey of the magellanic stellar history

AU - Martin, Nicolas F.

AU - Nidever, David L.

AU - Besla, Gurtina

AU - Olsen, Knut

AU - Walker, Alistair R.

AU - Vivas, A. Katherina

AU - Gruendl, Robert A.

AU - Kaleida, Catherine C.

AU - Muñoz, Ricardo R.

AU - Blum, Robert D.

AU - Saha, Abhijit

AU - Conn, Blair C.

AU - Bell, Eric F.

AU - Chu, You Hua

AU - Cioni, M-R.L.

AU - De Boer, Thomas J. L.

AU - Gallart, Carme

AU - Jin, Shoko

AU - Kunder, Andrea

AU - Majewski, Steven R.

AU - Martinez-Delgado, David

AU - Monachesi, Antonela

AU - Monelli, Matteo

AU - Monteagudo, Lara

AU - Noël, Noelia E.D.

AU - Olszewski, Edward W.

AU - Stringfellow, Guy S.

AU - Van Der Marel, Roeland P.

AU - Zaritsky, Dennis

N1 - Date of Acceptance: 31/03/2015

PY - 2015/5/1

Y1 - 2015/5/1

N2 - We present the discovery of a new dwarf galaxy, Hydra II, found serendipitously within the data from the ongoing Survey of the Magellanic Stellar History conducted with the Dark Energy Camera on the Blanco 4 m Telescope. The new satellite is compact (r_h = 68 ± 11 pc) and faint (M_V = -4.8 ± 0.3), but well within the realm of dwarf galaxies. The stellar distribution of Hydra II in the color-magnitude diagram is well-described by a metal-poor ([Fe/H] = -2.2) and old (13 Gyr) isochrone and shows a distinct blue horizontal branch, some possible red clump stars, and faint stars that are suggestive of blue stragglers. At a heliocentric distance of 134 ± 10 kpc, Hydra II is located in a region of the Galactic halo that models have suggested may host material from the leading arm of the Magellanic Stream. A comparison with N-body simulations hints that the new dwarf galaxy could be or could have been a satellite of the Magellanic Clouds.

AB - We present the discovery of a new dwarf galaxy, Hydra II, found serendipitously within the data from the ongoing Survey of the Magellanic Stellar History conducted with the Dark Energy Camera on the Blanco 4 m Telescope. The new satellite is compact (r_h = 68 ± 11 pc) and faint (M_V = -4.8 ± 0.3), but well within the realm of dwarf galaxies. The stellar distribution of Hydra II in the color-magnitude diagram is well-described by a metal-poor ([Fe/H] = -2.2) and old (13 Gyr) isochrone and shows a distinct blue horizontal branch, some possible red clump stars, and faint stars that are suggestive of blue stragglers. At a heliocentric distance of 134 ± 10 kpc, Hydra II is located in a region of the Galactic halo that models have suggested may host material from the leading arm of the Magellanic Stream. A comparison with N-body simulations hints that the new dwarf galaxy could be or could have been a satellite of the Magellanic Clouds.

KW - galaxies: individual (Hydra II)

KW - Local Group

KW - Magellanic Clouds

U2 - 10.1088/2041-8205/804/1/L5

DO - 10.1088/2041-8205/804/1/L5

M3 - Article

AN - SCOPUS:84928820684

SN - 2041-8205

VL - 804

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - L5

ER -

Hydra II: a faint and compact milky way dwarf galaxy found in the survey of the magellanic stellar history

Abstract

Keywords

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