SPECTROSCOPIC CONFIRMATION of the DWARF SPHEROIDAL GALAXY d0994+71 AS A MEMBER of the M81 GROUP of GALAXIES

Elisa Toloba; David Sand; Puragra Guhathakurta; Kristin Chiboucas; Denija Crnojević; Joshua D. Simon

doi:10.3847/2041-8205/830/1/L21

SPECTROSCOPIC CONFIRMATION of the DWARF SPHEROIDAL GALAXY d0994+71 AS A MEMBER of the M81 GROUP of GALAXIES

Elisa Toloba, David Sand, Puragra Guhathakurta, Kristin Chiboucas, Denija Crnojević, Joshua D. Simon

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

7 Scopus citations

Abstract

We use Keck/DEIMOS spectroscopy to measure the first velocity and metallicity of a dwarf spheroidal (dSph) galaxy beyond the Local Group using resolved stars. Our target, d0944+71, is a faint dSph found in the halo of the massive spiral galaxy M81 by Chiboucas et al. We coadd the spectra of 27 individual stars and measure a heliocentric radial velocity of -38 ±10 km s^-1. This velocity is consistent with d0944+71 being gravitationally bound to M81. We coadd the spectra of the 23 stars that are consistent with being red giant branch stars and measure an overall metallicity of [Fe/H] = -1.3 ±0.3 based on the calcium triplet lines. This metallicity is consistent with d0944+71 following the metallicity-luminosity relation for Local Group dSphs. We investigate several potential sources of observational bias but find that our sample of targeted stars is representative of the metallicity distribution function of d0944+71 and any stellar contamination due to seeing effects is negligible. The low ellipticity of the galaxy and its position in the metallicity-luminosity relation suggest that d0944+71 has not been affected by strong tidal stripping.

Original language	English (US)
Article number	L21
Journal	Astrophysical Journal Letters
Volume	830
Issue number	1
DOIs	https://doi.org/10.3847/2041-8205/830/1/L21
State	Published - Oct 10 2016
Externally published	Yes

Keywords

galaxies: dwarf
galaxies: evolution
galaxies: individual (M81, d0944+71)
galaxies: kinematics and dynamics
galaxies: stellar content

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/2041-8205/830/1/L21

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@article{86ae08cb79c04c7796a32931c5b762f6,

title = "SPECTROSCOPIC CONFIRMATION of the DWARF SPHEROIDAL GALAXY d0994+71 AS A MEMBER of the M81 GROUP of GALAXIES",

abstract = "We use Keck/DEIMOS spectroscopy to measure the first velocity and metallicity of a dwarf spheroidal (dSph) galaxy beyond the Local Group using resolved stars. Our target, d0944+71, is a faint dSph found in the halo of the massive spiral galaxy M81 by Chiboucas et al. We coadd the spectra of 27 individual stars and measure a heliocentric radial velocity of -38 ±10 km s-1. This velocity is consistent with d0944+71 being gravitationally bound to M81. We coadd the spectra of the 23 stars that are consistent with being red giant branch stars and measure an overall metallicity of [Fe/H] = -1.3 ±0.3 based on the calcium triplet lines. This metallicity is consistent with d0944+71 following the metallicity-luminosity relation for Local Group dSphs. We investigate several potential sources of observational bias but find that our sample of targeted stars is representative of the metallicity distribution function of d0944+71 and any stellar contamination due to seeing effects is negligible. The low ellipticity of the galaxy and its position in the metallicity-luminosity relation suggest that d0944+71 has not been affected by strong tidal stripping.",

keywords = "galaxies: dwarf, galaxies: evolution, galaxies: individual (M81, d0944+71), galaxies: kinematics and dynamics, galaxies: stellar content",

author = "Elisa Toloba and David Sand and Puragra Guhathakurta and Kristin Chiboucas and Denija Crnojevi{\'c} and Simon, {Joshua D.}",

note = "Funding Information: E.T. and P.G. acknowledge the NSF grants AST-1010039 and AST-1412504. D.J.S. is supported by NSF grants AST-1412504 and AST-1517649 and J.D.S. by AST-1412792. The work of D.J.S. was partially performed at the Aspen Center for Physics, which is supported by National Science Foundation grant PHY- 1066293. Publisher Copyright: {\textcopyright} 2016. The American Astronomical Society. All rights reserved..",

year = "2016",

month = oct,

day = "10",

doi = "10.3847/2041-8205/830/1/L21",

language = "English (US)",

volume = "830",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

publisher = "American Astronomical Society",

number = "1",

}

TY - JOUR

T1 - SPECTROSCOPIC CONFIRMATION of the DWARF SPHEROIDAL GALAXY d0994+71 AS A MEMBER of the M81 GROUP of GALAXIES

AU - Toloba, Elisa

AU - Sand, David

AU - Guhathakurta, Puragra

AU - Chiboucas, Kristin

AU - Crnojević, Denija

AU - Simon, Joshua D.

N1 - Funding Information: E.T. and P.G. acknowledge the NSF grants AST-1010039 and AST-1412504. D.J.S. is supported by NSF grants AST-1412504 and AST-1517649 and J.D.S. by AST-1412792. The work of D.J.S. was partially performed at the Aspen Center for Physics, which is supported by National Science Foundation grant PHY- 1066293. Publisher Copyright: © 2016. The American Astronomical Society. All rights reserved..

PY - 2016/10/10

Y1 - 2016/10/10

N2 - We use Keck/DEIMOS spectroscopy to measure the first velocity and metallicity of a dwarf spheroidal (dSph) galaxy beyond the Local Group using resolved stars. Our target, d0944+71, is a faint dSph found in the halo of the massive spiral galaxy M81 by Chiboucas et al. We coadd the spectra of 27 individual stars and measure a heliocentric radial velocity of -38 ±10 km s-1. This velocity is consistent with d0944+71 being gravitationally bound to M81. We coadd the spectra of the 23 stars that are consistent with being red giant branch stars and measure an overall metallicity of [Fe/H] = -1.3 ±0.3 based on the calcium triplet lines. This metallicity is consistent with d0944+71 following the metallicity-luminosity relation for Local Group dSphs. We investigate several potential sources of observational bias but find that our sample of targeted stars is representative of the metallicity distribution function of d0944+71 and any stellar contamination due to seeing effects is negligible. The low ellipticity of the galaxy and its position in the metallicity-luminosity relation suggest that d0944+71 has not been affected by strong tidal stripping.

AB - We use Keck/DEIMOS spectroscopy to measure the first velocity and metallicity of a dwarf spheroidal (dSph) galaxy beyond the Local Group using resolved stars. Our target, d0944+71, is a faint dSph found in the halo of the massive spiral galaxy M81 by Chiboucas et al. We coadd the spectra of 27 individual stars and measure a heliocentric radial velocity of -38 ±10 km s-1. This velocity is consistent with d0944+71 being gravitationally bound to M81. We coadd the spectra of the 23 stars that are consistent with being red giant branch stars and measure an overall metallicity of [Fe/H] = -1.3 ±0.3 based on the calcium triplet lines. This metallicity is consistent with d0944+71 following the metallicity-luminosity relation for Local Group dSphs. We investigate several potential sources of observational bias but find that our sample of targeted stars is representative of the metallicity distribution function of d0944+71 and any stellar contamination due to seeing effects is negligible. The low ellipticity of the galaxy and its position in the metallicity-luminosity relation suggest that d0944+71 has not been affected by strong tidal stripping.

KW - galaxies: dwarf

KW - galaxies: evolution

KW - galaxies: individual (M81, d0944+71)

KW - galaxies: kinematics and dynamics

KW - galaxies: stellar content

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UR - http://www.scopus.com/inward/citedby.url?scp=84991728472&partnerID=8YFLogxK

U2 - 10.3847/2041-8205/830/1/L21

DO - 10.3847/2041-8205/830/1/L21

M3 - Article

AN - SCOPUS:84991728472

SN - 2041-8205

VL - 830

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - L21

ER -

SPECTROSCOPIC CONFIRMATION of the DWARF SPHEROIDAL GALAXY d0994+71 AS A MEMBER of the M81 GROUP of GALAXIES

Abstract

Keywords

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