A Keck/DEIMOS spectroscopic survey of faint Galactic satellites : searching for the least massive dwarf galaxies
Identifieur interne : 00A219 ( Main/Merge ); précédent : 00A218; suivant : 00A220A Keck/DEIMOS spectroscopic survey of faint Galactic satellites : searching for the least massive dwarf galaxies
Auteurs : N. F. Martin [Allemagne] ; R. A. Ibata [France] ; S. C. Chapman [Royaume-Uni, Canada] ; M. Irwin [Royaume-Uni] ; G. F. Lewis [Australie]Source :
- Monthly Notices of the Royal Astronomical Society [ 0035-8711 ] ; 2007.
Descripteurs français
- Pascal (Inist)
English descriptors
- KwdEn :
Abstract
We present the results of a spectroscopic survey of the recently discovered faint Milky Way satellites Bootes, Ursa Major I, Ursa Major II and Willman 1 (Will). Using the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, we have obtained samples that contain from ∼ 15 to ∼85 probable members of these satellites for which we derive radial velocities precise to a few km s-1 down to i ∼ 21-22. About half of these stars are observed with a high enough signal-to-noise ratio to estimate their metallicity to within ±0.2 dex. The characteristics of all the observed stars are made available, along with those of the Canes Venatici I dwarf galaxy that have been analysed in a companion paper. From this data set, we show that Ursa Major II is the only object that does not show a clear radial velocity peak. However, the measured systemic radial velocity (ùr = 115 ± 5kms-1) is in good agreement with simulations in which this object is the progenitor of the recently discovered Orphan Stream. The three other satellites show velocity dispersions that make them highly dark matter dominated systems (under the usual assumptions of symmetry and virial equilibrium). In particular, we show that despite its small size and faintness, the Will object is not a globular cluster given its metallicity scatter over -2.0 ≤ [Fe/H] ≤ -1.0 and is therefore almost certainly a dwarf galaxy or dwarf galaxy remnant. We measure a radial velocity dispersion of only 4.3 +2.3-1.3 km s-1 around a systemic velocity of -12.3 ± 2.3 km s-1 which implies a mass-to-light ratio of ∼700 and a total mass of ∼5 x 105 MO for this satellite, making it the least massive satellite galaxy known to date. Such a low mass could mean that the 107 MO limit that had until now never been crossed for Milky Way and Andromeda satellite galaxies may only be an observational limit and that fainter, less massive systems exist within the Local Group. However, more modelling and an extended search for potential extratidal stars are required to rule out the possibility that these systems have not been significantly heated by tidal interaction.
Links toward previous steps (curation, corpus...)
- to stream PascalFrancis, to step Corpus: 003A10
- to stream PascalFrancis, to step Curation: 002678
- to stream PascalFrancis, to step Checkpoint: 003B07
Links to Exploration step
Pascal:07-0409359Le document en format XML
<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en" level="a">A Keck/DEIMOS spectroscopic survey of faint Galactic satellites : searching for the least massive dwarf galaxies</title><author><name sortKey="Martin, N F" sort="Martin, N F" uniqKey="Martin N" first="N. F." last="Martin">N. F. Martin</name><affiliation wicri:level="3"><inist:fA14 i1="01"><s1>Max-Planck-Institut für Astronomie, Königstuhl 17</s1><s2>69117 Heidelberg</s2><s3>DEU</s3><sZ>1 aut.</sZ></inist:fA14><country>Allemagne</country><placeName><region type="land" nuts="1">Bade-Wurtemberg</region><region type="district" nuts="2">District de Karlsruhe</region><settlement type="city">Heidelberg</settlement></placeName></affiliation></author><author><name sortKey="Ibata, R A" sort="Ibata, R A" uniqKey="Ibata R" first="R. A." last="Ibata">R. A. Ibata</name><affiliation wicri:level="1"><inist:fA14 i1="02"><s1>Observatoire de Strasbourg, 11, rue de l'Université</s1><s2>67000 Strasbourg</s2><s3>FRA</s3><sZ>2 aut.</sZ></inist:fA14><country>France</country><wicri:noRegion>67000 Strasbourg</wicri:noRegion><placeName><settlement type="city">Strasbourg</settlement><region type="region" nuts="2">Grand Est</region><region type="old region" nuts="2">Alsace (région administrative)</region></placeName></affiliation></author><author><name sortKey="Chapman, S C" sort="Chapman, S C" uniqKey="Chapman S" first="S. C." last="Chapman">S. C. Chapman</name><affiliation wicri:level="1"><inist:fA14 i1="03"><s1>Institute of Astronomy, Madingley Road</s1><s2>Cambridge CB3 0HA</s2><s3>GBR</s3><sZ>3 aut.</sZ><sZ>4 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB3 0HA</wicri:noRegion></affiliation><affiliation wicri:level="1"><inist:fA14 i1="04"><s1>Department of Physics and Astronomy, University of Victoria</s1><s2>Victoria, BC, V8P 1A1</s2><s3>CAN</s3><sZ>3 aut.</sZ></inist:fA14><country>Canada</country><wicri:noRegion>Victoria, BC, V8P 1A1</wicri:noRegion></affiliation></author><author><name sortKey="Irwin, M" sort="Irwin, M" uniqKey="Irwin M" first="M." last="Irwin">M. Irwin</name><affiliation wicri:level="1"><inist:fA14 i1="03"><s1>Institute of Astronomy, Madingley Road</s1><s2>Cambridge CB3 0HA</s2><s3>GBR</s3><sZ>3 aut.</sZ><sZ>4 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB3 0HA</wicri:noRegion></affiliation></author><author><name sortKey="Lewis, G F" sort="Lewis, G F" uniqKey="Lewis G" first="G. F." last="Lewis">G. F. Lewis</name><affiliation wicri:level="4"><inist:fA14 i1="05"><s1>Institute of Astronomy, School of Physics, A29 University of Sydney</s1><s2>NSW 2006</s2><s3>AUS</s3><sZ>5 aut.</sZ></inist:fA14><country>Australie</country><placeName><settlement type="city">Sydney</settlement><region type="état">Nouvelle-Galles du Sud</region></placeName><orgName type="university">Université de Sydney</orgName></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">INIST</idno><idno type="inist">07-0409359</idno><date when="2007">2007</date><idno type="stanalyst">PASCAL 07-0409359 INIST</idno><idno type="RBID">Pascal:07-0409359</idno><idno type="wicri:Area/PascalFrancis/Corpus">003A10</idno><idno type="wicri:Area/PascalFrancis/Curation">002678</idno><idno type="wicri:Area/PascalFrancis/Checkpoint">003B07</idno><idno type="wicri:explorRef" wicri:stream="PascalFrancis" wicri:step="Checkpoint">003B07</idno><idno type="wicri:doubleKey">0035-8711:2007:Martin N:a:keck:deimos</idno><idno type="wicri:Area/Main/Merge">00A219</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a">A Keck/DEIMOS spectroscopic survey of faint Galactic satellites : searching for the least massive dwarf galaxies</title><author><name sortKey="Martin, N F" sort="Martin, N F" uniqKey="Martin N" first="N. F." last="Martin">N. F. Martin</name><affiliation wicri:level="3"><inist:fA14 i1="01"><s1>Max-Planck-Institut für Astronomie, Königstuhl 17</s1><s2>69117 Heidelberg</s2><s3>DEU</s3><sZ>1 aut.</sZ></inist:fA14><country>Allemagne</country><placeName><region type="land" nuts="1">Bade-Wurtemberg</region><region type="district" nuts="2">District de Karlsruhe</region><settlement type="city">Heidelberg</settlement></placeName></affiliation></author><author><name sortKey="Ibata, R A" sort="Ibata, R A" uniqKey="Ibata R" first="R. A." last="Ibata">R. A. Ibata</name><affiliation wicri:level="1"><inist:fA14 i1="02"><s1>Observatoire de Strasbourg, 11, rue de l'Université</s1><s2>67000 Strasbourg</s2><s3>FRA</s3><sZ>2 aut.</sZ></inist:fA14><country>France</country><wicri:noRegion>67000 Strasbourg</wicri:noRegion><placeName><settlement type="city">Strasbourg</settlement><region type="region" nuts="2">Grand Est</region><region type="old region" nuts="2">Alsace (région administrative)</region></placeName></affiliation></author><author><name sortKey="Chapman, S C" sort="Chapman, S C" uniqKey="Chapman S" first="S. C." last="Chapman">S. C. Chapman</name><affiliation wicri:level="1"><inist:fA14 i1="03"><s1>Institute of Astronomy, Madingley Road</s1><s2>Cambridge CB3 0HA</s2><s3>GBR</s3><sZ>3 aut.</sZ><sZ>4 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB3 0HA</wicri:noRegion></affiliation><affiliation wicri:level="1"><inist:fA14 i1="04"><s1>Department of Physics and Astronomy, University of Victoria</s1><s2>Victoria, BC, V8P 1A1</s2><s3>CAN</s3><sZ>3 aut.</sZ></inist:fA14><country>Canada</country><wicri:noRegion>Victoria, BC, V8P 1A1</wicri:noRegion></affiliation></author><author><name sortKey="Irwin, M" sort="Irwin, M" uniqKey="Irwin M" first="M." last="Irwin">M. Irwin</name><affiliation wicri:level="1"><inist:fA14 i1="03"><s1>Institute of Astronomy, Madingley Road</s1><s2>Cambridge CB3 0HA</s2><s3>GBR</s3><sZ>3 aut.</sZ><sZ>4 aut.</sZ></inist:fA14><country>Royaume-Uni</country><wicri:noRegion>Cambridge CB3 0HA</wicri:noRegion></affiliation></author><author><name sortKey="Lewis, G F" sort="Lewis, G F" uniqKey="Lewis G" first="G. F." last="Lewis">G. F. Lewis</name><affiliation wicri:level="4"><inist:fA14 i1="05"><s1>Institute of Astronomy, School of Physics, A29 University of Sydney</s1><s2>NSW 2006</s2><s3>AUS</s3><sZ>5 aut.</sZ></inist:fA14><country>Australie</country><placeName><settlement type="city">Sydney</settlement><region type="état">Nouvelle-Galles du Sud</region></placeName><orgName type="university">Université de Sydney</orgName></affiliation></author></analytic><series><title level="j" type="main">Monthly Notices of the Royal Astronomical Society</title><title level="j" type="abbreviated">Mon. Not. R. Astron. Soc.</title><idno type="ISSN">0035-8711</idno><imprint><date when="2007">2007</date></imprint></series></biblStruct></sourceDesc><seriesStmt><title level="j" type="main">Monthly Notices of the Royal Astronomical Society</title><title level="j" type="abbreviated">Mon. Not. R. Astron. Soc.</title><idno type="ISSN">0035-8711</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Dark matter</term><term>Deimos</term><term>Dwarf galaxies</term><term>Dynamics</term><term>Globular clusters</term><term>Kinematics</term><term>Local group</term><term>Mars satellite</term><term>Mass to light ratio</term><term>Metallicity</term><term>Milky Way</term><term>Radial velocity</term><term>Satellite galaxies</term><term>Signal-to-noise ratio</term><term>Star clusters</term><term>Tidal interaction</term><term>Velocity dispersion</term></keywords><keywords scheme="Pascal" xml:lang="fr"><term>Deimos</term><term>Galaxies naines</term><term>Voie lactée</term><term>Vitesse radiale</term><term>Rapport signal bruit</term><term>Métallicité</term><term>Dispersion vitesse</term><term>Matière sombre</term><term>Amas globulaire</term><term>Rapport masse luminosité</term><term>Galaxies compagnons</term><term>Groupe local</term><term>Cinématique</term><term>Dynamique</term><term>Satellite Mars</term><term>Amas stellaire</term><term>Interaction tidale</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">We present the results of a spectroscopic survey of the recently discovered faint Milky Way satellites Bootes, Ursa Major I, Ursa Major II and Willman 1 (Will). Using the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, we have obtained samples that contain from ∼ 15 to ∼85 probable members of these satellites for which we derive radial velocities precise to a few km s<sup>-1</sup> down to i ∼ 21-22. About half of these stars are observed with a high enough signal-to-noise ratio to estimate their metallicity to within ±0.2 dex. The characteristics of all the observed stars are made available, along with those of the Canes Venatici I dwarf galaxy that have been analysed in a companion paper. From this data set, we show that Ursa Major II is the only object that does not show a clear radial velocity peak. However, the measured systemic radial velocity (ù<sub>r</sub> = 115 ± 5kms<sup>-1</sup>) is in good agreement with simulations in which this object is the progenitor of the recently discovered Orphan Stream. The three other satellites show velocity dispersions that make them highly dark matter dominated systems (under the usual assumptions of symmetry and virial equilibrium). In particular, we show that despite its small size and faintness, the Will object is not a globular cluster given its metallicity scatter over -2.0 ≤ [Fe/H] ≤ -1.0 and is therefore almost certainly a dwarf galaxy or dwarf galaxy remnant. We measure a radial velocity dispersion of only 4.3 +2.3-1.3 km s<sup>-1</sup> around a systemic velocity of -12.3 ± 2.3 km s<sup>-1</sup> which implies a mass-to-light ratio of ∼700 and a total mass of ∼5 x 10<sup>5</sup> M<sub>O</sub> for this satellite, making it the least massive satellite galaxy known to date. Such a low mass could mean that the 10<sup>7</sup> M<sub>O</sub> limit that had until now never been crossed for Milky Way and Andromeda satellite galaxies may only be an observational limit and that fainter, less massive systems exist within the Local Group. However, more modelling and an extended search for potential extratidal stars are required to rule out the possibility that these systems have not been significantly heated by tidal interaction.</div></front></TEI><affiliations><list><country><li>Allemagne</li><li>Australie</li><li>Canada</li><li>France</li><li>Royaume-Uni</li></country><region><li>Alsace (région administrative)</li><li>Bade-Wurtemberg</li><li>District de Karlsruhe</li><li>Grand Est</li><li>Nouvelle-Galles du Sud</li></region><settlement><li>Heidelberg</li><li>Strasbourg</li><li>Sydney</li></settlement><orgName><li>Université de Sydney</li></orgName></list><tree><country name="Allemagne"><region name="Bade-Wurtemberg"><name sortKey="Martin, N F" sort="Martin, N F" uniqKey="Martin N" first="N. F." last="Martin">N. F. Martin</name></region></country><country name="France"><region name="Grand Est"><name sortKey="Ibata, R A" sort="Ibata, R A" uniqKey="Ibata R" first="R. A." last="Ibata">R. A. Ibata</name></region></country><country name="Royaume-Uni"><noRegion><name sortKey="Chapman, S C" sort="Chapman, S C" uniqKey="Chapman S" first="S. C." last="Chapman">S. C. Chapman</name></noRegion><name sortKey="Irwin, M" sort="Irwin, M" uniqKey="Irwin M" first="M." last="Irwin">M. Irwin</name></country><country name="Canada"><noRegion><name sortKey="Chapman, S C" sort="Chapman, S C" uniqKey="Chapman S" first="S. C." last="Chapman">S. C. Chapman</name></noRegion></country><country name="Australie"><region name="Nouvelle-Galles du Sud"><name sortKey="Lewis, G F" sort="Lewis, G F" uniqKey="Lewis G" first="G. F." last="Lewis">G. F. Lewis</name></region></country></tree></affiliations></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Wicri/Asie/explor/AustralieFrV1/Data/Main/Merge
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 00A219 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Main/Merge/biblio.hfd -nk 00A219 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Wicri/Asie
|area= AustralieFrV1
|flux= Main
|étape= Merge
|type= RBID
|clé= Pascal:07-0409359
|texte= A Keck/DEIMOS spectroscopic survey of faint Galactic satellites : searching for the least massive dwarf galaxies
}}
| This area was generated with Dilib version V0.6.33. |  |