COMPARING M31 AND MILKY WAY SATELLITES: THE EXTENDED STAR FORMATION HISTORIES OF ANDROMEDA II AND ANDROMEDA XVI

Daniel R. Weisz; Evan D. Skillman; Sebastian L. Hidalgo; Matteo Monelli; Andrew E. Dolphin; Alan McConnachie; Edouard J. Bernard; Carme Gallart; Antonio Aparicio; Michael Boylan-Kolchin; Santi Cassisi; Andrew A. Cole; Henry C. Ferguson; Mike Irwin; Nicolas F. Martin; Lucio Mayer; Kristen B. W. McQuinn; Julio F. Navarro; Peter B. Stetson

doi:10.1088/0004-637X/789/1/24

COMPARING M31 AND MILKY WAY SATELLITES: THE EXTENDED STAR FORMATION HISTORIES OF ANDROMEDA II AND ANDROMEDA XVI

Daniel R. Weisz^*, Evan D. Skillman, Sebastian L. Hidalgo, Matteo Monelli, Andrew E. Dolphin, Alan McConnachie, Edouard J. Bernard, Carme Gallart, Antonio Aparicio, Michael Boylan-Kolchin, Santi Cassisi, Andrew A. Cole, Henry C. Ferguson, Mike Irwin, Nicolas F. Martin, Lucio Mayer, Kristen B. W. McQuinn, Julio F. Navarro, Peter B. Stetson

^*Corresponding author for this work

School of Physics and Astronomy

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

Abstract

We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; M-V = -12.0; log(M-star/M-circle dot) similar to 6.7) and Andromeda XVI (And XVI; M-V = -7.5; log(M-star/M-circle dot) similar to 4.9) yielding color-magnitude diagrams that extend at least 1 mag below the oldest main-sequence turnoff, and are similar in quality to those available for the MW companions. And II and And XVI show strikingly similar SFHs: both formed 50%-70% of their total stellar mass between 12.5 and 5 Gyr ago (z similar to 5-0.5) and both were abruptly quenched similar to 5 Gyr ago (z similar to 0.5). The predominance of intermediate age populations in And XVI makes it qualitatively different from faint companions of the MW and clearly not a pre-reionization fossil. Neither And II nor And XVI appears to have a clear analog among MW companions, and the degree of similarity in the SFHs of And II and And XVI is not seen among comparably faint-luminous pairs of MW satellites. These findings provide hints that satellite galaxy evolution may vary substantially among hosts of similar stellar mass. Although comparably deep observations of more M31 satellites are needed to further explore this hypothesis, our results underline the need for caution when interpreting satellite galaxies of an individual system in a broader cosmological context.

Original language	English
Article number	24
Number of pages	6
Journal	Astrophysical Journal
Volume	789
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/789/1/24
Publication status	Published - 1 Jul 2014

Keywords / Materials (for Non-textual outputs)

galaxies: dwarf
galaxies: individual (And II, And XVI)
Galaxy: evolution
Galaxy: formation
Local Group
DWARF SPHEROIDAL GALAXIES
HUBBLE-SPACE-TELESCOPE
LOCAL GROUP
WFPC2 OBSERVATIONS
REIONIZATION
KINEMATICS
COMPANIONS
ABUNDANCES
EVOLUTION
DISK

Access to Document

10.1088/0004-637X/789/1/24

Cite this

Weisz, D. R., Skillman, E. D., Hidalgo, S. L., Monelli, M., Dolphin, A. E., McConnachie, A., Bernard, E. J., Gallart, C., Aparicio, A., Boylan-Kolchin, M., Cassisi, S., Cole, A. A., Ferguson, H. C., Irwin, M., Martin, N. F., Mayer, L., McQuinn, K. B. W., Navarro, J. F., & Stetson, P. B. (2014). COMPARING M31 AND MILKY WAY SATELLITES: THE EXTENDED STAR FORMATION HISTORIES OF ANDROMEDA II AND ANDROMEDA XVI. Astrophysical Journal, 789(1), Article 24. https://doi.org/10.1088/0004-637X/789/1/24

@article{1dea6cbb9c4d4a628f2dff6dcdac6c4e,

title = "COMPARING M31 AND MILKY WAY SATELLITES: THE EXTENDED STAR FORMATION HISTORIES OF ANDROMEDA II AND ANDROMEDA XVI",

abstract = "We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; M-V = -12.0; log(M-star/M-circle dot) similar to 6.7) and Andromeda XVI (And XVI; M-V = -7.5; log(M-star/M-circle dot) similar to 4.9) yielding color-magnitude diagrams that extend at least 1 mag below the oldest main-sequence turnoff, and are similar in quality to those available for the MW companions. And II and And XVI show strikingly similar SFHs: both formed 50%-70% of their total stellar mass between 12.5 and 5 Gyr ago (z similar to 5-0.5) and both were abruptly quenched similar to 5 Gyr ago (z similar to 0.5). The predominance of intermediate age populations in And XVI makes it qualitatively different from faint companions of the MW and clearly not a pre-reionization fossil. Neither And II nor And XVI appears to have a clear analog among MW companions, and the degree of similarity in the SFHs of And II and And XVI is not seen among comparably faint-luminous pairs of MW satellites. These findings provide hints that satellite galaxy evolution may vary substantially among hosts of similar stellar mass. Although comparably deep observations of more M31 satellites are needed to further explore this hypothesis, our results underline the need for caution when interpreting satellite galaxies of an individual system in a broader cosmological context.",

keywords = "galaxies: dwarf, galaxies: individual (And II, And XVI), Galaxy: evolution, Galaxy: formation, Local Group, DWARF SPHEROIDAL GALAXIES, HUBBLE-SPACE-TELESCOPE, LOCAL GROUP, WFPC2 OBSERVATIONS, REIONIZATION, KINEMATICS, COMPANIONS, ABUNDANCES, EVOLUTION, DISK",

author = "Weisz, {Daniel R.} and Skillman, {Evan D.} and Hidalgo, {Sebastian L.} and Matteo Monelli and Dolphin, {Andrew E.} and Alan McConnachie and Bernard, {Edouard J.} and Carme Gallart and Antonio Aparicio and Michael Boylan-Kolchin and Santi Cassisi and Cole, {Andrew A.} and Ferguson, {Henry C.} and Mike Irwin and Martin, {Nicolas F.} and Lucio Mayer and McQuinn, {Kristen B. W.} and Navarro, {Julio F.} and Stetson, {Peter B.}",

year = "2014",

month = jul,

day = "1",

doi = "10.1088/0004-637X/789/1/24",

language = "English",

volume = "789",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP Publishing",

number = "1",

}

Weisz, DR, Skillman, ED, Hidalgo, SL, Monelli, M, Dolphin, AE, McConnachie, A, Bernard, EJ, Gallart, C, Aparicio, A, Boylan-Kolchin, M, Cassisi, S, Cole, AA, Ferguson, HC, Irwin, M, Martin, NF, Mayer, L, McQuinn, KBW, Navarro, JF & Stetson, PB 2014, 'COMPARING M31 AND MILKY WAY SATELLITES: THE EXTENDED STAR FORMATION HISTORIES OF ANDROMEDA II AND ANDROMEDA XVI', Astrophysical Journal, vol. 789, no. 1, 24. https://doi.org/10.1088/0004-637X/789/1/24

TY - JOUR

T1 - COMPARING M31 AND MILKY WAY SATELLITES

T2 - THE EXTENDED STAR FORMATION HISTORIES OF ANDROMEDA II AND ANDROMEDA XVI

AU - Weisz, Daniel R.

AU - Skillman, Evan D.

AU - Hidalgo, Sebastian L.

AU - Monelli, Matteo

AU - Dolphin, Andrew E.

AU - McConnachie, Alan

AU - Bernard, Edouard J.

AU - Gallart, Carme

AU - Aparicio, Antonio

AU - Boylan-Kolchin, Michael

AU - Cassisi, Santi

AU - Cole, Andrew A.

AU - Ferguson, Henry C.

AU - Irwin, Mike

AU - Martin, Nicolas F.

AU - Mayer, Lucio

AU - McQuinn, Kristen B. W.

AU - Navarro, Julio F.

AU - Stetson, Peter B.

PY - 2014/7/1

Y1 - 2014/7/1

N2 - We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; M-V = -12.0; log(M-star/M-circle dot) similar to 6.7) and Andromeda XVI (And XVI; M-V = -7.5; log(M-star/M-circle dot) similar to 4.9) yielding color-magnitude diagrams that extend at least 1 mag below the oldest main-sequence turnoff, and are similar in quality to those available for the MW companions. And II and And XVI show strikingly similar SFHs: both formed 50%-70% of their total stellar mass between 12.5 and 5 Gyr ago (z similar to 5-0.5) and both were abruptly quenched similar to 5 Gyr ago (z similar to 0.5). The predominance of intermediate age populations in And XVI makes it qualitatively different from faint companions of the MW and clearly not a pre-reionization fossil. Neither And II nor And XVI appears to have a clear analog among MW companions, and the degree of similarity in the SFHs of And II and And XVI is not seen among comparably faint-luminous pairs of MW satellites. These findings provide hints that satellite galaxy evolution may vary substantially among hosts of similar stellar mass. Although comparably deep observations of more M31 satellites are needed to further explore this hypothesis, our results underline the need for caution when interpreting satellite galaxies of an individual system in a broader cosmological context.

AB - We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; M-V = -12.0; log(M-star/M-circle dot) similar to 6.7) and Andromeda XVI (And XVI; M-V = -7.5; log(M-star/M-circle dot) similar to 4.9) yielding color-magnitude diagrams that extend at least 1 mag below the oldest main-sequence turnoff, and are similar in quality to those available for the MW companions. And II and And XVI show strikingly similar SFHs: both formed 50%-70% of their total stellar mass between 12.5 and 5 Gyr ago (z similar to 5-0.5) and both were abruptly quenched similar to 5 Gyr ago (z similar to 0.5). The predominance of intermediate age populations in And XVI makes it qualitatively different from faint companions of the MW and clearly not a pre-reionization fossil. Neither And II nor And XVI appears to have a clear analog among MW companions, and the degree of similarity in the SFHs of And II and And XVI is not seen among comparably faint-luminous pairs of MW satellites. These findings provide hints that satellite galaxy evolution may vary substantially among hosts of similar stellar mass. Although comparably deep observations of more M31 satellites are needed to further explore this hypothesis, our results underline the need for caution when interpreting satellite galaxies of an individual system in a broader cosmological context.

KW - galaxies: dwarf

KW - galaxies: individual (And II, And XVI)

KW - Galaxy: evolution

KW - Galaxy: formation

KW - Local Group

KW - DWARF SPHEROIDAL GALAXIES

KW - HUBBLE-SPACE-TELESCOPE

KW - LOCAL GROUP

KW - WFPC2 OBSERVATIONS

KW - REIONIZATION

KW - KINEMATICS

KW - COMPANIONS

KW - ABUNDANCES

KW - EVOLUTION

KW - DISK

U2 - 10.1088/0004-637X/789/1/24

DO - 10.1088/0004-637X/789/1/24

M3 - Article

SN - 0004-637X

VL - 789

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

M1 - 24

ER -

COMPARING M31 AND MILKY WAY SATELLITES: THE EXTENDED STAR FORMATION HISTORIES OF ANDROMEDA II AND ANDROMEDA XVI

Abstract

Keywords / Materials (for Non-textual outputs)

Access to Document

Fingerprint

Cite this