Internal kinematics of the Andromeda II dwarf spheroidal galaxy

Patrick Côté, Mario Mateo, Edward W Olszewski, K. H. Cook

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

The High-Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of ≃2 km s-1 for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II (And II). We find a weighted mean radial velocity of v̄r = -188 ± 3 km s-1 and a central velocity dispersion of σ0 = 9.3+2.7-2.6 km s-1. There may be evidence for a radial velocity gradient across the face of the galaxy, although the significance of this result is low because of the small number of stars having measured velocities. Our best estimate for the global mass-to-light ratio of And II is M/Lv = 20.9+13.9-10.1 M ⊙/Lv, ⊙. This value is similar to those of several Galactic dwarf spheroidal galaxies and is consistent with the presence of a massive dark halo in And II.

Original languageEnglish (US)
Pages (from-to)147-151
Number of pages5
JournalAstrophysical Journal
Volume526
Issue number1 PART 1
StatePublished - Nov 20 1999

Fingerprint

Andromeda
dwarf galaxies
radial velocity
kinematics
mass to light ratios
halos
telescopes
spectrometers
galaxies
stars
gradients
high resolution
estimates
spectrometer

Keywords

  • Galaxies: dwarf
  • Galaxies: Individual (Andromeda II)
  • Galaxies: kinematics and dynamics

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Côté, P., Mateo, M., Olszewski, E. W., & Cook, K. H. (1999). Internal kinematics of the Andromeda II dwarf spheroidal galaxy. Astrophysical Journal, 526(1 PART 1), 147-151.

Internal kinematics of the Andromeda II dwarf spheroidal galaxy. / Côté, Patrick; Mateo, Mario; Olszewski, Edward W; Cook, K. H.

In: Astrophysical Journal, Vol. 526, No. 1 PART 1, 20.11.1999, p. 147-151.

Research output: Contribution to journalArticle

Côté, P, Mateo, M, Olszewski, EW & Cook, KH 1999, 'Internal kinematics of the Andromeda II dwarf spheroidal galaxy', Astrophysical Journal, vol. 526, no. 1 PART 1, pp. 147-151.
Côté P, Mateo M, Olszewski EW, Cook KH. Internal kinematics of the Andromeda II dwarf spheroidal galaxy. Astrophysical Journal. 1999 Nov 20;526(1 PART 1):147-151.
Côté, Patrick ; Mateo, Mario ; Olszewski, Edward W ; Cook, K. H. / Internal kinematics of the Andromeda II dwarf spheroidal galaxy. In: Astrophysical Journal. 1999 ; Vol. 526, No. 1 PART 1. pp. 147-151.
@article{ca51529996d64a8eb4551ffd65fbbc8c,
title = "Internal kinematics of the Andromeda II dwarf spheroidal galaxy",
abstract = "The High-Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of ≃2 km s-1 for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II (And II). We find a weighted mean radial velocity of v̄r = -188 ± 3 km s-1 and a central velocity dispersion of σ0 = 9.3+2.7-2.6 km s-1. There may be evidence for a radial velocity gradient across the face of the galaxy, although the significance of this result is low because of the small number of stars having measured velocities. Our best estimate for the global mass-to-light ratio of And II is M/Lv = 20.9+13.9-10.1 M ⊙/Lv, ⊙. This value is similar to those of several Galactic dwarf spheroidal galaxies and is consistent with the presence of a massive dark halo in And II.",
keywords = "Galaxies: dwarf, Galaxies: Individual (Andromeda II), Galaxies: kinematics and dynamics",
author = "Patrick C{\^o}t{\'e} and Mario Mateo and Olszewski, {Edward W} and Cook, {K. H.}",
year = "1999",
month = "11",
day = "20",
language = "English (US)",
volume = "526",
pages = "147--151",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1 PART 1",

}

TY - JOUR

T1 - Internal kinematics of the Andromeda II dwarf spheroidal galaxy

AU - Côté, Patrick

AU - Mateo, Mario

AU - Olszewski, Edward W

AU - Cook, K. H.

PY - 1999/11/20

Y1 - 1999/11/20

N2 - The High-Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of ≃2 km s-1 for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II (And II). We find a weighted mean radial velocity of v̄r = -188 ± 3 km s-1 and a central velocity dispersion of σ0 = 9.3+2.7-2.6 km s-1. There may be evidence for a radial velocity gradient across the face of the galaxy, although the significance of this result is low because of the small number of stars having measured velocities. Our best estimate for the global mass-to-light ratio of And II is M/Lv = 20.9+13.9-10.1 M ⊙/Lv, ⊙. This value is similar to those of several Galactic dwarf spheroidal galaxies and is consistent with the presence of a massive dark halo in And II.

AB - The High-Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of ≃2 km s-1 for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II (And II). We find a weighted mean radial velocity of v̄r = -188 ± 3 km s-1 and a central velocity dispersion of σ0 = 9.3+2.7-2.6 km s-1. There may be evidence for a radial velocity gradient across the face of the galaxy, although the significance of this result is low because of the small number of stars having measured velocities. Our best estimate for the global mass-to-light ratio of And II is M/Lv = 20.9+13.9-10.1 M ⊙/Lv, ⊙. This value is similar to those of several Galactic dwarf spheroidal galaxies and is consistent with the presence of a massive dark halo in And II.

KW - Galaxies: dwarf

KW - Galaxies: Individual (Andromeda II)

KW - Galaxies: kinematics and dynamics

UR - http://www.scopus.com/inward/record.url?scp=0040249057&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0040249057&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0040249057

VL - 526

SP - 147

EP - 151

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART 1

ER -