The three-dimensional structure of the giant stellar stream in Andromeda
Identifieur interne : 002391 ( Istex/Corpus ); précédent : 002390; suivant : 002392The three-dimensional structure of the giant stellar stream in Andromeda
Auteurs : A. W. Mcconnachie ; M. J. Irwin ; R. A. Ibata ; A. M. N. Ferguson ; G. F. Lewis ; N. TanvirSource :
- Monthly Notices of the Royal Astronomical Society [ 0035-8711 ] ; 2003-08-21.
English descriptors
- KwdEn :
Abstract
The wide-field CCD camera at the Canada–France–Hawaii Telescope (CFHT) was used to survey the giant stellar stream in the Andromeda galaxy, resolving stars down the red giant branch in M31 to I≃ 25, a magnitude deeper than our previous Isaac Newton Telescope (INT) survey of this galaxy and extending 1° further out. The stream is seen to extend out to the south-east of M31 as far as we have surveyed (some , corresponding to a projected distance of ∼60 kpc). It is a linear structure in projection, and the eastern edge of the stream presents a sharp boundary in star counts, suggesting that it remains a coherent structure. By analysing the luminosity function of the metal-rich component of the stream, we find that, at the furthest extent of our survey, the stream is 100 kpc further away along the line of sight than M31. It can then be traced to a point on the north-western side of the galaxy where it is some 30 kpc in front of M31, at which point the stream turns away from our survey area.
Url:
DOI: 10.1046/j.1365-8711.2003.06785.x
Links to Exploration step
ISTEX:C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BDLe document en format XML
<record><TEI wicri:istexFullTextTei="biblStruct"><teiHeader><fileDesc><titleStmt><title>The three-dimensional structure of the giant stellar stream in Andromeda</title><author><name sortKey="Mcconnachie, A W" sort="Mcconnachie, A W" uniqKey="Mcconnachie A" first="A. W." last="Mcconnachie">A. W. Mcconnachie</name><affiliation><mods:affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail: alan@ast.cam.ac.uk</mods:affiliation></affiliation><affiliation><mods:affiliation></mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail: alan@ast.cam.ac.uk</mods:affiliation></affiliation></author><author><name sortKey="Irwin, M J" sort="Irwin, M J" uniqKey="Irwin M" first="M. J." last="Irwin">M. J. Irwin</name><affiliation><mods:affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</mods:affiliation></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><mods:affiliation>Observatoire de Strasbourg, 11, rue de l'Université, F-67000 Strasbourg, France</mods:affiliation></affiliation></author><author><name sortKey="Ferguson, A M N" sort="Ferguson, A M N" uniqKey="Ferguson A" first="A. M. N." last="Ferguson">A. M. N. Ferguson</name><affiliation><mods:affiliation>Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching, Germany</mods:affiliation></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><mods:affiliation>Institute of Astronomy, School of Physics, A29, University of Sydney, NSW 2006, Australia</mods:affiliation></affiliation></author><author><name sortKey="Tanvir, N" sort="Tanvir, N" uniqKey="Tanvir N" first="N." last="Tanvir">N. Tanvir</name><affiliation><mods:affiliation>Physical Sciences, University of Hertfordshire, Hatfield AL10 9AB</mods:affiliation></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">ISTEX</idno><idno type="RBID">ISTEX:C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD</idno><date when="2003" year="2003">2003</date><idno type="doi">10.1046/j.1365-8711.2003.06785.x</idno><idno type="url">https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/fulltext/pdf</idno><idno type="wicri:Area/Istex/Corpus">002391</idno><idno type="wicri:explorRef" wicri:stream="Istex" wicri:step="Corpus" wicri:corpus="ISTEX">002391</idno></publicationStmt><sourceDesc><biblStruct><analytic><title level="a">The three-dimensional structure of the giant stellar stream in Andromeda</title><author><name sortKey="Mcconnachie, A W" sort="Mcconnachie, A W" uniqKey="Mcconnachie A" first="A. W." last="Mcconnachie">A. W. Mcconnachie</name><affiliation><mods:affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail: alan@ast.cam.ac.uk</mods:affiliation></affiliation><affiliation><mods:affiliation></mods:affiliation></affiliation><affiliation><mods:affiliation>E-mail: alan@ast.cam.ac.uk</mods:affiliation></affiliation></author><author><name sortKey="Irwin, M J" sort="Irwin, M J" uniqKey="Irwin M" first="M. J." last="Irwin">M. J. Irwin</name><affiliation><mods:affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</mods:affiliation></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><mods:affiliation>Observatoire de Strasbourg, 11, rue de l'Université, F-67000 Strasbourg, France</mods:affiliation></affiliation></author><author><name sortKey="Ferguson, A M N" sort="Ferguson, A M N" uniqKey="Ferguson A" first="A. M. N." last="Ferguson">A. M. N. Ferguson</name><affiliation><mods:affiliation>Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching, Germany</mods:affiliation></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><mods:affiliation>Institute of Astronomy, School of Physics, A29, University of Sydney, NSW 2006, Australia</mods:affiliation></affiliation></author><author><name sortKey="Tanvir, N" sort="Tanvir, N" uniqKey="Tanvir N" first="N." last="Tanvir">N. Tanvir</name><affiliation><mods:affiliation>Physical Sciences, University of Hertfordshire, Hatfield AL10 9AB</mods:affiliation></affiliation></author></analytic><monogr></monogr><series><title level="j">Monthly Notices of the Royal Astronomical Society</title><title level="j" type="abbrev">Mon. Not. R. Astron. Soc.</title><idno type="ISSN">0035-8711</idno><idno type="eISSN">1365-2966</idno><imprint><publisher>Blackwell Science Ltd</publisher><pubPlace>Oxford, UK</pubPlace><date type="published" when="2003-08-21">2003-08-21</date><biblScope unit="volume">343</biblScope><biblScope unit="issue">4</biblScope><biblScope unit="page" from="1335">1335</biblScope><biblScope unit="page" to="1340">1340</biblScope></imprint><idno type="ISSN">0035-8711</idno></series></biblStruct></sourceDesc><seriesStmt><idno type="ISSN">0035-8711</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Local Group</term><term>galaxies: evolution</term><term>galaxies: general</term><term>galaxies: haloes</term><term>galaxies: interactions</term><term>galaxies: stellar content</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract">The wide-field CCD camera at the Canada–France–Hawaii Telescope (CFHT) was used to survey the giant stellar stream in the Andromeda galaxy, resolving stars down the red giant branch in M31 to I≃ 25, a magnitude deeper than our previous Isaac Newton Telescope (INT) survey of this galaxy and extending 1° further out. The stream is seen to extend out to the south-east of M31 as far as we have surveyed (some , corresponding to a projected distance of ∼60 kpc). It is a linear structure in projection, and the eastern edge of the stream presents a sharp boundary in star counts, suggesting that it remains a coherent structure. By analysing the luminosity function of the metal-rich component of the stream, we find that, at the furthest extent of our survey, the stream is 100 kpc further away along the line of sight than M31. It can then be traced to a point on the north-western side of the galaxy where it is some 30 kpc in front of M31, at which point the stream turns away from our survey area.</div></front></TEI><istex><corpusName>oup</corpusName><author><json:item><name>A. W. McConnachie</name><affiliations><json:string>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</json:string><json:string>E-mail: alan@ast.cam.ac.uk</json:string><json:null></json:null><json:string>E-mail: alan@ast.cam.ac.uk</json:string></affiliations></json:item><json:item><name>M. J. Irwin</name><affiliations><json:string>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</json:string></affiliations></json:item><json:item><name>R. A. Ibata</name><affiliations><json:string>Observatoire de Strasbourg, 11, rue de l'Université, F-67000 Strasbourg, France</json:string></affiliations></json:item><json:item><name>A. M. N. Ferguson</name><affiliations><json:string>Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching, Germany</json:string></affiliations></json:item><json:item><name>G. F. Lewis</name><affiliations><json:string>Institute of Astronomy, School of Physics, A29, University of Sydney, NSW 2006, Australia</json:string></affiliations></json:item><json:item><name>N. Tanvir</name><affiliations><json:string>Physical Sciences, University of Hertfordshire, Hatfield AL10 9AB</json:string></affiliations></json:item></author><subject><json:item><value>galaxies: evolution</value></json:item><json:item><value>galaxies: general</value></json:item><json:item><value>galaxies: haloes</value></json:item><json:item><value>galaxies: interactions</value></json:item><json:item><value>Local Group</value></json:item><json:item><value>galaxies: stellar content</value></json:item></subject><arkIstex>ark:/67375/HXZ-PKJF0SQX-5</arkIstex><language><json:string>unknown</json:string></language><originalGenre><json:string>research-article</json:string></originalGenre><abstract>The wide-field CCD camera at the Canada–France–Hawaii Telescope (CFHT) was used to survey the giant stellar stream in the Andromeda galaxy, resolving stars down the red giant branch in M31 to I≃ 25, a magnitude deeper than our previous Isaac Newton Telescope (INT) survey of this galaxy and extending 1° further out. The stream is seen to extend out to the south-east of M31 as far as we have surveyed (some , corresponding to a projected distance of ∼60 kpc). It is a linear structure in projection, and the eastern edge of the stream presents a sharp boundary in star counts, suggesting that it remains a coherent structure. By analysing the luminosity function of the metal-rich component of the stream, we find that, at the furthest extent of our survey, the stream is 100 kpc further away along the line of sight than M31. It can then be traced to a point on the north-western side of the galaxy where it is some 30 kpc in front of M31, at which point the stream turns away from our survey area.</abstract><qualityIndicators><score>8.02</score><pdfWordCount>3860</pdfWordCount><pdfCharCount>19867</pdfCharCount><pdfVersion>1.4</pdfVersion><pdfPageCount>6</pdfPageCount><pdfPageSize>595.276 x 782.362 pts</pdfPageSize><refBibsNative>true</refBibsNative><abstractWordCount>180</abstractWordCount><abstractCharCount>1000</abstractCharCount><keywordCount>6</keywordCount></qualityIndicators><title>The three-dimensional structure of the giant stellar stream in Andromeda</title><genre><json:string>research-article</json:string></genre><host><title>Monthly Notices of the Royal Astronomical Society</title><language><json:string>unknown</json:string></language><issn><json:string>0035-8711</json:string></issn><eissn><json:string>1365-2966</json:string></eissn><publisherId><json:string>mnras</json:string></publisherId><volume>343</volume><issue>4</issue><pages><first>1335</first><last>1340</last></pages><genre><json:string>journal</json:string></genre></host><namedEntities><unitex><date><json:string>2001</json:string><json:string>2003</json:string></date><geogName></geogName><orgName><json:string>University of Sydney</json:string><json:string>University of Hertfordshire</json:string><json:string>Institute of Astronomy, School of Physics</json:string></orgName><orgName_funder></orgName_funder><orgName_provider></orgName_provider><persName><json:string>J. Irwin</json:string><json:string>F. Lewis</json:string><json:string>Newton Telescope</json:string><json:string>A. M. N. Ferguson</json:string><json:string>A. Ibata</json:string><json:string>A. W. McConnachie</json:string><json:string>Professor VandenBerg</json:string><json:string>By</json:string><json:string>N. Tanvir</json:string></persName><placeName><json:string>Australia</json:string><json:string>Canada</json:string><json:string>Strasbourg</json:string><json:string>France</json:string></placeName><ref_url><json:string>http://www.ast.cam.ac.uk/</json:string><json:string>http://www.cfht.hawaii.edu</json:string></ref_url><ref_bibl><json:string>Ibata et al. 2001a</json:string><json:string>Irwin & Lewis 2001</json:string><json:string>Ibata et al. 1994</json:string><json:string>White & Rees 1978</json:string><json:string>Quinn, Hernquist & Fullager 1993</json:string><json:string>Schwarzkopf & Dettmar 2000</json:string><json:string>Bellazzini, Ferraro & Ibata 2003</json:string><json:string>A. W. McConnachie et al.</json:string><json:string>McConnachie et al.</json:string><json:string>Ferguson et al. 2002</json:string><json:string>VandenBerg et al (2000)</json:string><json:string>Feltzing, Bensby & Lundstrom 2003</json:string><json:string>VandenBerg et al. (2000)</json:string><json:string>Carretta, Gratton & Sneden 2000</json:string><json:string>Sagar et al. (1999)</json:string><json:string>Ibata et al. 2001b</json:string><json:string>Johnston, Hernquist & Bolte 1996</json:string><json:string>Salaris & Cassisi 1997</json:string><json:string>Wheeler, Sneden & Truran 1989</json:string></ref_bibl><bibl></bibl></unitex></namedEntities><ark><json:string>ark:/67375/HXZ-PKJF0SQX-5</json:string></ark><categories><wos><json:string>science</json:string><json:string>astronomy & astrophysics</json:string></wos><scienceMetrix><json:string>natural sciences</json:string><json:string>physics & astronomy</json:string><json:string>astronomy & astrophysics</json:string></scienceMetrix><scopus><json:string>1 - Physical Sciences</json:string><json:string>2 - Earth and Planetary Sciences</json:string><json:string>3 - Space and Planetary Science</json:string><json:string>1 - Physical Sciences</json:string><json:string>2 - Physics and Astronomy</json:string><json:string>3 - Astronomy and Astrophysics</json:string></scopus><inist><json:string>sciences appliquees, technologies et medecines</json:string><json:string>sciences exactes et technologie</json:string><json:string>terre, ocean, espace</json:string><json:string>astronomie</json:string></inist></categories><publicationDate>2003</publicationDate><copyrightDate>2003</copyrightDate><doi><json:string>10.1046/j.1365-8711.2003.06785.x</json:string></doi><id>C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD</id><score>1</score><fulltext><json:item><extension>pdf</extension><original>true</original><mimetype>application/pdf</mimetype><uri>https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/fulltext/pdf</uri></json:item><json:item><extension>zip</extension><original>false</original><mimetype>application/zip</mimetype><uri>https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/fulltext/zip</uri></json:item><istex:fulltextTEI uri="https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/fulltext/tei"><teiHeader><fileDesc><titleStmt><title level="a">The three-dimensional structure of the giant stellar stream in Andromeda</title></titleStmt><publicationStmt><authority>ISTEX</authority><publisher scheme="https://publisher-list.data.istex.fr">Blackwell Science Ltd</publisher><pubPlace>Oxford, UK</pubPlace><availability><licence><p>© 2003 RAS</p></licence><p scheme="https://loaded-corpus.data.istex.fr/ark:/67375/XBH-GTWS0RDP-M">oup</p></availability><date>2003</date></publicationStmt><notesStmt><note type="research-article" scheme="https://content-type.data.istex.fr/ark:/67375/XTP-1JC4F85T-7">research-article</note><note type="journal" scheme="https://publication-type.data.istex.fr/ark:/67375/JMC-0GLKJH51-B">journal</note></notesStmt><sourceDesc><biblStruct type="inbook"><analytic><title level="a">The three-dimensional structure of the giant stellar stream in Andromeda</title><author xml:id="author-0000" corresp="yes"><persName><forename type="first">A. W.</forename><surname>McConnachie</surname></persName><email>alan@ast.cam.ac.uk</email><email>alan@ast.cam.ac.uk</email><affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</affiliation><affiliation></affiliation></author><author xml:id="author-0001"><persName><forename type="first">M. J.</forename><surname>Irwin</surname></persName><affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</affiliation></author><author xml:id="author-0002"><persName><forename type="first">R. A.</forename><surname>Ibata</surname></persName><affiliation>Observatoire de Strasbourg, 11, rue de l'Université, F-67000 Strasbourg, France</affiliation></author><author xml:id="author-0003"><persName><forename type="first">A. M. N.</forename><surname>Ferguson</surname></persName><affiliation>Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching, Germany</affiliation></author><author xml:id="author-0004"><persName><forename type="first">G. F.</forename><surname>Lewis</surname></persName><affiliation>Institute of Astronomy, School of Physics, A29, University of Sydney, NSW 2006, Australia</affiliation></author><author xml:id="author-0005"><persName><forename type="first">N.</forename><surname>Tanvir</surname></persName><affiliation>Physical Sciences, University of Hertfordshire, Hatfield AL10 9AB</affiliation></author><idno type="istex">C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD</idno><idno type="ark">ark:/67375/HXZ-PKJF0SQX-5</idno><idno type="DOI">10.1046/j.1365-8711.2003.06785.x</idno></analytic><monogr><title level="j">Monthly Notices of the Royal Astronomical Society</title><title level="j" type="abbrev">Mon. Not. R. Astron. Soc.</title><idno type="pISSN">0035-8711</idno><idno type="eISSN">1365-2966</idno><idno type="publisher-id">mnras</idno><idno type="PublisherID-hwp">mnras</idno><imprint><publisher>Blackwell Science Ltd</publisher><pubPlace>Oxford, UK</pubPlace><date type="published" when="2003-08-21"></date><biblScope unit="volume">343</biblScope><biblScope unit="issue">4</biblScope><biblScope unit="page" from="1335">1335</biblScope><biblScope unit="page" to="1340">1340</biblScope></imprint></monogr></biblStruct></sourceDesc></fileDesc><profileDesc><creation><date>2003</date></creation><abstract><p>The wide-field CCD camera at the Canada–France–Hawaii Telescope (CFHT) was used to survey the giant stellar stream in the Andromeda galaxy, resolving stars down the red giant branch in M31 to I≃ 25, a magnitude deeper than our previous Isaac Newton Telescope (INT) survey of this galaxy and extending 1° further out. The stream is seen to extend out to the south-east of M31 as far as we have surveyed (some , corresponding to a projected distance of ∼60 kpc). It is a linear structure in projection, and the eastern edge of the stream presents a sharp boundary in star counts, suggesting that it remains a coherent structure. By analysing the luminosity function of the metal-rich component of the stream, we find that, at the furthest extent of our survey, the stream is 100 kpc further away along the line of sight than M31. It can then be traced to a point on the north-western side of the galaxy where it is some 30 kpc in front of M31, at which point the stream turns away from our survey area.</p></abstract><textClass xml:lang="en"><keywords scheme="keyword"><list><head>Key words</head><item><term>galaxies: evolution</term></item><item><term>galaxies: general</term></item><item><term>galaxies: haloes</term></item><item><term>galaxies: interactions</term></item><item><term>Local Group</term></item><item><term>galaxies: stellar content</term></item></list></keywords></textClass></profileDesc><revisionDesc><change when="2003-08-21">Published</change></revisionDesc></teiHeader></istex:fulltextTEI><json:item><extension>txt</extension><original>false</original><mimetype>text/plain</mimetype><uri>https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/fulltext/txt</uri></json:item></fulltext><metadata><istex:metadataXml wicri:clean="corpus oup, element #text not found" wicri:toSee="no header"><istex:xmlDeclaration>version="1.0"</istex:xmlDeclaration><istex:docType PUBLIC="-//NLM//DTD Journal Publishing DTD v2.3 20070202//EN" URI="journalpublishing.dtd" name="istex:docType"></istex:docType><istex:document><article article-type="research-article">
<front>
<journal-meta>
<journal-id journal-id-type="hwp">mnras</journal-id>
<journal-id journal-id-type="publisher-id">mnras</journal-id>
<journal-title>Monthly Notices of the Royal Astronomical Society</journal-title>
<abbrev-journal-title>Mon. Not. R. Astron. Soc.</abbrev-journal-title>
<issn pub-type="ppub">0035-8711</issn>
<issn pub-type="epub">1365-2966</issn>
<publisher>
<publisher-name>Blackwell Science Ltd</publisher-name>
<publisher-loc>Oxford, UK</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.1046/j.1365-8711.2003.06785.x</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Papers</subject>
</subj-group>
</article-categories>
<title-group>
<article-title>The three-dimensional structure of the giant stellar stream in Andromeda</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author" corresp="yes">
<name><surname>McConnachie</surname><given-names>A. W.</given-names></name><xref ref-type="aff" rid="a1"><sup>1</sup></xref><xref ref-type="corresp" rid="cor1"><sup>⋆</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Irwin</surname><given-names>M. J.</given-names></name><xref ref-type="aff" rid="a1"><sup>1</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Ibata</surname><given-names>R. A.</given-names></name><xref ref-type="aff" rid="a2"><sup>2</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Ferguson</surname><given-names>A. M. N.</given-names></name><xref ref-type="aff" rid="a3"><sup>3</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Lewis</surname><given-names>G. F.</given-names></name><xref ref-type="aff" rid="a4"><sup>4</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Tanvir</surname><given-names>N.</given-names></name><xref ref-type="aff" rid="a5"><sup>5</sup></xref>
</contrib>
<aff id="a1"><label>1</label>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</aff>
<aff id="a2"><label>2</label>Observatoire de Strasbourg, 11, rue de l'Université, F-67000 Strasbourg, France</aff>
<aff id="a3"><label>3</label>Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching, Germany</aff>
<aff id="a4"><label>4</label>Institute of Astronomy, School of Physics, A29, University of Sydney, NSW 2006, Australia</aff>
<aff id="a5"><label>5</label>Physical Sciences, University of Hertfordshire, Hatfield AL10 9AB</aff>
</contrib-group>
<author-notes>
<corresp id="cor1"><label>⋆</label>E-mail: <email>alan@ast.cam.ac.uk</email></corresp>
</author-notes>
<pub-date pub-type="ppub">
<day>21</day>
<month>8</month>
<year>2003</year>
</pub-date>
<volume>343</volume>
<issue>4</issue>
<fpage>1335</fpage>
<lpage>1340</lpage>
<history>
<date date-type="received">
<day>8</day>
<month>5</month>
<year>2003</year>
</date>
<date date-type="accepted">
<day>9</day>
<month>5</month>
<year>2003</year>
</date>
</history>
<permissions>
<copyright-statement>© 2003 RAS</copyright-statement>
<copyright-year>2003</copyright-year>
</permissions>
<abstract>
<title>Abstract</title>
<p>The wide-field CCD camera at the Canada–France–Hawaii Telescope (CFHT) was used to survey the giant stellar stream in the Andromeda galaxy, resolving stars down the red giant branch in M31 to <italic>I</italic>≃ 25, a magnitude deeper than our previous Isaac Newton Telescope (INT) survey of this galaxy and extending 1° further out. The stream is seen to extend out to the south-east of M31 as far as we have surveyed (some <inline-graphic mimetype="image" xlink:href="343-4-1335-eq001.tif"></inline-graphic>, corresponding to a projected distance of ∼60 kpc). It is a linear structure in projection, and the eastern edge of the stream presents a sharp boundary in star counts, suggesting that it remains a coherent structure. By analysing the luminosity function of the metal-rich component of the stream, we find that, at the furthest extent of our survey, the stream is 100 kpc further away along the line of sight than M31. It can then be traced to a point on the north-western side of the galaxy where it is some 30 kpc in front of M31, at which point the stream turns away from our survey area.</p>
</abstract>
<kwd-group xml:lang="en">
<title>Key words</title>
<kwd>galaxies: evolution</kwd>
<kwd>galaxies: general</kwd>
<kwd>galaxies: haloes</kwd>
<kwd>galaxies: interactions</kwd>
<kwd>Local Group</kwd>
<kwd>galaxies: stellar content</kwd>
</kwd-group>
</article-meta>
</front>
<body>
<sec id="ss1">
<label>1</label>
<title>Introduction</title>
<p>Stellar streams are the remnants of structures that have become perturbed or disrupted as a result of the action of gravitational tides. In the hierarchical formation model of galaxy haloes, smaller systems merge first and form the larger galaxies we see today (<xref ref-type="bibr" rid="bib18">White & Rees 1978</xref>). As such, these structures are expected to be common, and examination of their properties gives valuable information about the galactic formation process. In the outer regions of haloes, dynamical times are sufficiently long to leave many structures detectable over much of the age of the Universe (e.g. <xref ref-type="bibr" rid="bib10">Johnston, Hernquist & Bolte 1996</xref>) and so these streams can trace the leftovers of even ancient accretions. Indeed, under some favourable conditions, the galaxy potential can leave massive streams essentially intact for all cosmic time.</p>
<p>Within our Local Group, there is a lot of observational evidence that galaxy mergers are an ongoing process. The discovery of the Sagittarius dwarf galaxy by <xref ref-type="bibr" rid="bib6">Ibata, Gilmore & Irwin (1994)</xref> revealed that our own Galaxy is undergoing strong interactions with its companions. Further observations detected a tidal stream associated with the disruption of this galaxy (e.g. <xref ref-type="bibr" rid="bib7">Ibata et al. 2001a</xref>). Indeed, several of the globular clusters of our Galaxy have been found to have been originally associated with this dwarf galaxy (<xref ref-type="bibr" rid="bib6">Ibata et al. 1994</xref>; <xref ref-type="bibr" rid="bib1">Bellazzini, Ferraro & Ibata 2003</xref>). One of the most favoured explanations for the formation of the thick disc is that it is caused by a violent merging event (e.g. <xref ref-type="bibr" rid="bib11">Quinn, Hernquist & Fullager 1993</xref>; <xref ref-type="bibr" rid="bib15">Schwarzkopf & Dettmar 2000</xref>; <xref ref-type="bibr" rid="bib4">Feltzing, Bensby & Lundstrom 2003</xref>). Disentangling the merger history of galaxies is therefore of prime importance; streams are ideal tracers of this process.</p>
<p>The discovery of a giant stellar stream in the outer regions of our neighbouring giant galaxy M31 was reported in two earlier contributions in this series (<xref ref-type="bibr" rid="bib8">Ibata et al. 2001b</xref>; <xref ref-type="bibr" rid="bib5">Ferguson et al. 2002</xref>). It is an apparently vast structure and our initial Isaac Newton Telescope Wide Field Camera (INT WFC) survey did not probe out far enough to find its true extent. Here, we report on our findings from a deeper survey using the Canada–France–Hawaii Telescope 12K camera (CFH12K), which probes further out and to fainter magnitudes than we had previously surveyed.</p>
</sec>
<sec id="ss2">
<label>2</label>
<title>Observations</title>
<p>During the nights of 2001 August 23, September 13–14 and September 17–18, 14 fields were observed with the 12k × 8k CFH12K camera, at the prime focus of the Canada–France–Hawaii Telescope (CFHT). The observations were kindly taken by CFHT staff, in service mode. Conditions were generally photometric, with good seeing of ≈0.8 arcsec. A set of three Mould <italic>V</italic>-band exposures and three Mould <italic>I</italic>-band exposures, each of a duration of 545 s, was secured per field. A negligible colour correction is involved to convert these filters to the standard Johnson–Kron–Cousins system.<xref ref-type="fn" rid="fn1"><sup>1</sup></xref>The data were preprocessed by CFHT staff with the CFHT pipeline software, to correct for bias offset, flat-fielding and fringing. We then applied the same object detection, classification, photometry and catalogue generation algorithms as we used successfully before on our INT-based survey (<xref ref-type="bibr" rid="bib9">Irwin & Lewis 2001</xref>).</p>
<p>The fields were selected to lie along the previously detected region of the Andromeda stream, and we extrapolated along this stream in a straight line ∼3° further out to the south-east and to the north-west. The arrangement of the survey regions presented here is displayed in <xref ref-type="fig" rid="fig1">Fig. 1</xref>, and the right ascension and declination of fields 1–8 and 12–14 are listed in <xref ref-type="fig" rid="tbl1">Table 1</xref>. The photometry of the three heavily crowded fields 9–11, which lie close to the centre of M31, will be presented elsewhere. Field 14 is used as a reference field, as no stream component was found there.</p>
<fig id="fig1" position="float">
<label>Figure 1.</label>
<caption>
<p>The location of the CFH12K fields used in this paper. The 2° radius ellipse marks the outer boundary of the optical disc of M31, whereas the curve is a segment of a 4° radius ellipse of semi-major axis ≃55 kpc and flattening 0.6 (this corresponds to the original limit of our INT survey). The CFHT field number is indicated either to the right or to the left of each field. Fields 9–11 are heavily crowded and will be the subject of a subsequent contribution.</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-fig001.tif"></graphic>
</fig>
<fig id="tbl1" position="float">
<label>Table 1.</label>
<caption>
<p>The depth change along the stream.</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-tbl001.tif"></graphic>
</fig>
</sec>
<sec id="ss3">
<label>3</label>
<title>Stellar Populations of the Stream</title>
<p>A typical field from our survey (field 6) which illustrates the quality of the CFHT data is shown in <xref ref-type="fig" rid="fig2">Fig. 2</xref>. This field is one of several that overlaps the INT survey region, although the CFHT data extends a full magnitude deeper than our previous survey. The overlap enables us to make an external comparison of the photometric systems and calibration. The internal overlaps between (most) CFHT fields and their external overlap with some of the INT data allowed us to update the calibration of two CFHT fields (2, 3) that were taken under slightly non-photometric conditions. After these adjustments, the photometric calibration systematic errors are at the level of ≈±2 per cent over the entire region surveyed. Overlaid on the colour–magnitude diagram are four well-studied globular cluster sequences (NGC 6397, NGC 1851, 47Tuc and NGC 6553) from <xref ref-type="bibr" rid="bib3">Da Costa & Armandroff (1990)</xref> and <xref ref-type="bibr" rid="bib12">Sagar et al. (1999)</xref> which span a range of different metallicities (left-hand panel), and also four evolutionary tracks (for α-enhanced 0.8-M<sub>⊙</sub> stars) from <xref ref-type="bibr" rid="bib16">VandenBerg et al. (2000)</xref> (right-hand panel). A wide range of stellar populations are evident in this field, spanning the full range of metallicities represented by the fiducial sequences (−0.2 ≥[Fe/H]≥−1.9). Inspection of a sequence of these diagrams shows evidence for a metal-poor halo population with a metallicity spanning roughly [Fe/H]≈−2 to −0.7; in addition to this, a more metal-rich population is evident in the majority of the fields. Using the fiducial sequences to define the metallicity distribution function, we can attribute a mean metallicity of [Fe/H]≈−0.5 to this component, with a dispersion of ≈−0.5 dex. This population is clearly seen to extend out to field 1 in our CFHT survey data, where it still remains a numerous component: around 1000 stream stars are detected in field 1 to <italic>I</italic>= 23.5. This is in contrast to the metal-poor halo component that virtually disappears by this galactocentric distance (∼4°).</p>
<fig id="fig2" position="float">
<label>Figure 2.</label>
<caption>
<p>Colour–magnitude diagrams of field 6. Error bars show typical uncertainties in the photometry at <italic>I</italic>= 21.0, 21.5 and 22.0. In the left-hand panel, we have overlaid four well-studied globular clusters sequences of different metallicities. From left to right, these are NGC 6397 ([Fe/H]=−1.9), NGC 1851 ([Fe/H]=−1.3), 47Tuc ([Fe/H]=−0.7) and NGC 6553 ([Fe/H]=−0.2). In the right-hand panel are four VandenBerg tracks for a 0.8-M<sub>⊙</sub> star with [α/Fe]= 0.3. The metallicities that these correspond to, from left to right, are [Fe/H]=−1.8, −1.3, −0.7 and −0.4. For all the overlays, we have assumed a distance modulus of 24.47 and an average reddening of <italic>E</italic>(<italic>B</italic>−<italic>V</italic>) = 0.07 (following <xref ref-type="bibr" rid="bib14">Schlegel, Finkbeiner & Davis 1998</xref>).</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-fig002.tif"></graphic>
</fig>
<p>The evolutionary tracks we have selected correspond to [α/Fe]= 0.3, because CNO and other α-process elements, which dominate the heavy element composition, are thought to be enhanced relative to solar for Galactic halo stars (e.g. <xref ref-type="bibr" rid="bib17">Wheeler, Sneden & Truran 1989</xref>; <xref ref-type="bibr" rid="bib2">Carretta, Gratton & Sneden 2000</xref>). These tracks are seen to be in good agreement with the globular cluster sequences and our data. In particular, the <italic>I</italic> magnitude of the tip of the red giant branch (TRGB) of the tracks appears to match up well as a function of metallicity. We will make use of this property in Section 4.4 in order to determine the relative distance of the metal-rich population to the bulk of the stellar population of M31.</p>
</sec>
<sec id="ss4">
<label>4</label>
<title>Three-Dimensional Structure of the Andromeda Stream</title>
<sec id="ss4-1">
<label>4.1</label>
<title>Stellar profile across the stream</title>
<p>In the INT data, the stream appeared as a fairly straight structure pointing away to the south-east from the centre of the galaxy. With our extra CFHT data, we are now in a position to constrain better the projected profile of the stream on the sky. A reference line was chosen that follows a path parallel to the direction of the CFHT survey fields and that passes through the centre of M31. The density of sources perpendicular to this line satisfying 20.5 < <italic>I</italic> < 22.5 and <italic>V</italic>−<italic>I</italic> > 2, for fields 1 to 8, is displayed as a solid line in <xref ref-type="fig" rid="fig3">Fig. 3</xref>. This figure demonstrates that there is a rapid rise in number counts from the north-eastern side of the stream towards the south-western side, with the density of sources increasing by a factor of ∼2 over <inline-graphic mimetype="image" xlink:href="343-4-1335-eq002.tif"></inline-graphic>. However, after the peak, the distribution is almost flat up to the south-western edge of our survey area. This is consistent with the sharp edge to the stream seen in the INT survey, although at this time we cannot constrain the behaviour of the south-western edge of the stream. To investigate the radial dependency, we divided the CFHT survey data into 4 bins (dotted lines). In <xref ref-type="fig" rid="fig3">Fig. 3</xref>, the shallowest histogram is for fields 1 – 3, the next is for fields 4–5, and the remaining two are for fields 6–7 and 8, respectively. The distribution of sources in each of these bins can be observed to have a similar shape; in particular, we find that the position of the peak of the distribution varies by less than <inline-graphic mimetype="image" xlink:href="343-4-1335-eq003.tif"></inline-graphic> over the 4° line between fields 1 and 8. However, the spatial profile of the stream beyond <inline-graphic mimetype="image" xlink:href="343-4-1335-eq004.tif"></inline-graphic> is broader, showing that the stream of width <inline-graphic mimetype="image" xlink:href="343-4-1335-eq005.tif"></inline-graphic> appears to fan out into a wider distribution in the outer regions.</p>
<fig id="fig3" position="float">
<label>Figure 3.</label>
<caption>
<p>The distribution of stars satisfying 20.5 < <italic>I</italic> < 22.5 and <italic>V</italic>−<italic>I</italic> > 2 orthogonal to the stream in fields 1-8. The shallowest histogram is for fields 1 – 3, the next is for fields 4–5, and the remaining two are for fields 6–7 and 8, respectively. The solid line is the combined histogram for all these fields. The distance displayed on the <italic>x</italic>-axis is the perpendicular distance from the line which is parallel to our survey and which passes through the centre of M31. The counts increase sharply from the left-hand (eastern) side, a feature which is seen consistently along the stream.</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-fig003.tif"></graphic>
</fig>
<p>Likewise, by separating the stars in <xref ref-type="fig" rid="fig3">Fig. 3</xref> with <inline-graphic mimetype="image" xlink:href="343-4-1335-eq006.tif"></inline-graphic>, we find that there is no significant difference in the shape of the histograms with that for <inline-graphic mimetype="image" xlink:href="343-4-1335-eq007.tif"></inline-graphic>. We had expected that for <inline-graphic mimetype="image" xlink:href="343-4-1335-eq008.tif"></inline-graphic>, the contribution of the stream would be small compared with the halo, and so the histograms would be flatter in appearance. Instead, it would appear that the stream contamination is still significant in the <inline-graphic mimetype="image" xlink:href="343-4-1335-eq009.tif"></inline-graphic> region.</p>
<p><xref ref-type="fig" rid="fig4">Fig. 4</xref> shows how the number density of these stars varies along the path defined above (fields 9, 10 and 11 have not been used because of crowding problems). As expected, the star counts increase as we approach the centre of M31. However, there is an excess of stars clearly visible for <inline-graphic mimetype="image" xlink:href="343-4-1335-eq010.tif"></inline-graphic>, which is highlighted in <xref ref-type="fig" rid="fig4">Fig. 4</xref> by comparison with the profile for <italic>d</italic> > 0° (its reflection about <italic>d</italic>= 0° is shown as a dot–dashed line). The CFHT fields were selected to highlight the stream which is clearly delineated in azimuth (<xref ref-type="bibr" rid="bib5">Ferguson et al. 2002</xref>); thus we attribute this excess to the stream. Although we believe the stream to be present at <italic>d</italic> > 0° (Section 4.4), its stellar density by this point is much smaller compared with other M31 components.</p>
<fig id="fig4" position="float">
<label>Figure 4.</label>
<caption>
<p>The distribution of stars along the path of the stream, as defined in the previous figure. The dotted line is a mirrored version of the data from fields 12 and 13, to illustrate the large excess of stars resulting from the stellar stream obvious in fields 1–8 for a distance of <inline-graphic mimetype="image" xlink:href="343-4-1335-eq011.tif"></inline-graphic>. The dip at −2° is caused by the gap between fields 5 and 6.</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-fig004.tif"></graphic>
</fig>
</sec>
<sec id="ss4-2">
<label>4.2</label>
<title>Stream distance relative to M31</title>
<p>The <italic>I</italic>-band magnitude of the TRGB is now recognized as a good standard candle for metal-poor ([Fe/H] < −0.7) old (>2 Gyr) stellar populations (e.g. <xref ref-type="bibr" rid="bib13">Salaris & Cassisi 1997</xref>). However, as we go to redder, more metal-rich populations, the luminosity decreases, owing to the effect of increased opacity in the stellar atmosphere. This is clearly observed in our colour–magnitude diagrams. As such, in order to gain a distance estimate of the stream relative to M31, we need to calibrate the redder (<italic>V</italic>−<italic>I</italic>≳ 2.2), metal-rich stream to the bluer (<italic>V</italic>−<italic>I</italic>≲ 2.2) M31 component and therefore need to know how the TRGB behaves as a function of colour.</p>
<p><xref ref-type="bibr" rid="bib16">VandenBerg et al. (2000)</xref> present evolutionary tracks for a range of stellar masses (0.5 ≤ M<sub>⊙</sub>≤ 1.0), with a range of metallicities (−2.31 ≤[Fe/H]≤−0.30). A selection of these tracks are shown in <xref ref-type="fig" rid="fig2">Fig. 2</xref>. In the left-hand panel of <xref ref-type="fig" rid="fig5">Fig. 5</xref>, we show the predicted location of the TRGB for 0.8-M<sub>⊙</sub> stars with [α/Fe]= 0.3 as a function of metallicity for these tracks. This is overlaid on one of our INT WFC survey fields (#76 located at <inline-graphic mimetype="image" xlink:href="343-4-1335-eq012.tif"></inline-graphic>) from a central region of M31 with a similar colour spread on the red giant branch. Evidently, there is good agreement between these theoretical evolutionary tracks and our M31 data. The INT passbands have been converted to <italic>V</italic> and <italic>I</italic> using <italic>I</italic>=<italic>i</italic>' − 0.101 × (<italic>V</italic>−<italic>I</italic>) and <italic>V</italic>=<italic>V</italic>' + 0.005 × (<italic>V</italic>−<italic>I</italic>). These transformations have been derived by comparison to observations of several Landolt standard fields.<xref ref-type="fn" rid="fn2"><sup>2</sup></xref></p>
<fig id="fig5" position="float">
<label>Figure 5.</label>
<caption>
<p>The left-hand panel shows an inner field from our M31 INT WFC survey, converted to <italic>V</italic> and <italic>I</italic> using the transformation equations given in the text. The location of the TRGB is seen readily. Overlaid is the behaviour of the tip as a function of metallicity, as given by the evolutionary tracks of <xref ref-type="bibr" rid="bib16">VandenBerg et al. (2000)</xref>. Detailed inspection shows that the tracks are in good agreement with the data. The right-hand panel shows field 8 from our CFH12K survey. By calibrating the accuracy of the Vandenberg tracks in predicting the magnitude of the TRGB in our M31 field in the left-hand panel, we can measure the distance variation between the stream-dominated component (<italic>V</italic>−<italic>I</italic>≳ 2.2) and the M31-dominated component (<italic>V</italic>−<italic>I</italic>≲ 2.2) in the field in the right-hand panel. This places the stream component in field 8 at approximately the same distance as the bulk of M31.</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-fig005.tif"></graphic>
</fig>
<p>In order to calibrate this model to the data, we adjust every <italic>I</italic> magnitude for stars in the M31 field using the differential model TRGB magnitudes with respect to a fiducial colour of <italic>V</italic>−<italic>I</italic>= 1.6. We then construct luminosity functions in the ranges 1.4 < <italic>V</italic>−<italic>I</italic> < 2.2 and 2.2 < <italic>V</italic>−<italic>I</italic> < 2.8 to represent the metal-poor and metal-rich components, respectively. Using a data-adaptive least-squares technique (McConnachie et al., in preparation), we measure the relative locations of the two TRGBs. The model-corrected metal-rich TRGB is systematically ≈0.1 mag brighter than the metal-poor TRGB and defines an empirical correction to the model-corrected TRGB magnitude.</p>
<p>We now apply this metallicity correction to field 8 in our CFHT data, as it is both the closest field to M31 and has the highest signal. The colour–magnitude diagram of this field is shown in the right-hand panel of <xref ref-type="fig" rid="fig5">Fig. 5</xref>. By applying the magnitude transformation on the stars and by taking into account the 0.1 mag difference between the redder and bluer TRGBs that we would expect were the components all at one distance, we conclude that, in field 8, there is no significant difference between the distance of the stream component and that of the bulk of M31.</p>
</sec>
<sec id="ss4-3">
<label>4.3</label>
<title>Relative distance change along the stream</title>
<p>With a link between the stream distance and the distance of M31 in field 8, it is now possible to examine how this distance changes with respect to M31 as a function of stream position. To do this, we cross-correlate the stream-dominated <italic>I</italic>-band luminosity function (2.5 < <italic>V</italic>−<italic>I</italic> < 3.5) in each field with the equivalent luminosity function in field 8. Any shift measured is a direct indicator of the stream distance. Examples are shown in <xref ref-type="fig" rid="fig6">Fig. 6</xref>. In all cases, field 14 is used as a reference field and a scaled (smoothed) version of its luminosity function is subtracted from each field analysed to account for varying foreground Galactic contamination. The luminosity functions are constructed using only objects classified as stellar sources in both the <italic>V</italic> and <italic>I</italic> filters. Although significant incompleteness caused by the <italic>V</italic>-band sets in at <italic>I</italic>≈ 22 for the redder objects, this is sufficiently beyond the peak of the red star luminosity function to not affect the cross-correlation, even with slight variations in field-to-field depths. Further tests using only <italic>I</italic>-band stellar detections satisfying <italic>V</italic>−<italic>I</italic> > 2.5 support this conclusion.</p>
<fig id="fig6" position="float">
<label>Figure 6.</label>
<caption>
<p>The top panel contains the foreground-corrected <italic>I</italic>-band luminosity function (using field 14 as the reference) for field 2 in the range 2.5 ≤<italic>V</italic>−<italic>I</italic>≤ 3.5, so as to isolate the stream component. This is cross-correlated against the equivalent luminosity function for field 8 (lower panel). The dotted lines are the locations of the peak in the luminosity function, which has clearly shifted to fainter magnitudes for field 2, implying that the stream here is much further away than in field 8.</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-fig006.tif"></graphic>
</fig>
<p>The results of the cross-correlation are shown in <xref ref-type="fig" rid="fig7">Fig. 7</xref> and are tabulated in <xref ref-type="fig" rid="tbl1">Table 1</xref>. The main contributors to the errors in the TRGB distance determinations are: the rms errors in the least-squares fit and cross-correlations which average ≃±0.03 mag; the photometric calibration error of ≃±0.02 mag; and model-dependent systematics from the various fits of the order of ≃±0.03. This leads to a total error of ≃±20 kpc in the distances.</p>
<fig id="fig7" position="float">
<label>Figure 7.</label>
<caption>
<p>The distance variation along the tidal stream, measured by cross-correlating the <italic>I</italic>-band luminosity function of field 8 with the other fields. The <italic>x</italic>-axis is the distance in degrees of the centre of each field from the intersection of the line with the semimajor axis of M31.</p>
</caption>
<graphic mimetype="image" xlink:href="343-4-1335-fig007.tif"></graphic>
</fig>
<p>The projection on the sky and the distance variation along the stream point to an almost linear structure in the south-east region, aligned at roughly 60° to the line of sight and extending out to distances well beyond 100 kpc from the centre of M31. No stream component is detected in field 14, although there is a clear signal in the inner half of field 13. The stream must therefore be wrapping around the centre of M31 toward the north-east. The distance variation between the two ends of our survey is ≈140 kpc, implying that the true length of the surveyed region of the stream is >160 kpc.</p>
</sec>
</sec>
<sec id="ss5">
<label>5</label>
<title>Conclusions</title>
<p>The tidal stream discovered by our survey of M31 (<xref ref-type="bibr" rid="bib8">Ibata et al. 2001b</xref>) extends linearly over at least 6° of the sky. In fact, we still have not surveyed out far enough to find the far south-eastern end. By analysing the metal-rich red giant branch luminosity function in the <italic>I</italic> band and comparing them to the evolutionary tracks of <xref ref-type="bibr" rid="bib16">VandenBerg et al (2000)</xref>, we are able to measure a radial distance change of the order of 140 kpc between the two ends of our survey, with the stream extending from approximately 100 kpc behind to 40 kpc in front of M31. We also see evidence that the stream then proceeds to wrap itself around M31. This information confirms that the Andromeda stream is a gigantic structure, angled at approximately 60° to our line of sight. Additionally, by analysing the stellar profile across the stream, we find that it remains a coherent structure, at least on the north-eastern edge. Its stellar distribution also appears to be fairly constant with increasing galactocentric distance. However, more observations are required in order to determine the true extent of this vast object.</p>
</sec>
</body>
<back>
<ack>
<sec id="ss6">
<title>Acknowledgments</title>
<p>This work is based on data collected at the Canada–France–Hawaii Telescope supported by INSU at Mauna Kea, Hawaii. The research of AMNF has been supported by a Marie Curie Fellowship of the European Community under contract number HPMF-CT-2002-01758. We would like to thank Professor VandenBerg for supplying us with his evolutionary tracks.</p>
</sec>
</ack>
<ref-list>
<title>References</title>
<ref id="bib1">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Bellazzini</surname><given-names>M.</given-names></name><name><surname>Ferraro</surname><given-names>F. R.</given-names></name><name><surname>Ibata</surname><given-names>R.</given-names></name></person-group>, <year>2003</year>, <source>AJ</source>, <volume>125</volume>, <fpage>188</fpage></citation>
</ref>
<ref id="bib2">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Carretta</surname><given-names>E.</given-names></name><name><surname>Gratton</surname><given-names>R. G.</given-names></name><name><surname>Sneden</surname><given-names>C.</given-names></name></person-group>, <year>2000</year>, <source>A&A</source>, <volume>356</volume>, <fpage>238</fpage></citation>
</ref>
<ref id="bib3">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Da Costa</surname><given-names>G. S.</given-names></name><name><surname>Armandroff</surname><given-names>T. E.</given-names></name></person-group>, <year>1990</year>, <source>AJ</source>, <volume>100</volume>, <fpage>162</fpage></citation>
</ref>
<ref id="bib4">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Feltzing</surname><given-names>S.</given-names></name><name><surname>Bensby</surname><given-names>T.</given-names></name><name><surname>Lundstrom</surname><given-names>I.</given-names></name></person-group>, <year>2003</year>, <source>A&A</source>, <volume>397</volume>, <fpage>L1</fpage></citation>
</ref>
<ref id="bib5">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Ferguson</surname><given-names>A. M. N.</given-names></name><name><surname>Irwin</surname><given-names>M.</given-names></name><name><surname>Ibata</surname><given-names>R.</given-names></name><name><surname>Lewis</surname><given-names>G.</given-names></name><name><surname>Tanvir</surname><given-names>N.</given-names></name></person-group>, <year>2002</year>, <source>AJ</source>, <volume>124</volume>, <fpage>1452</fpage></citation>
</ref>
<ref id="bib6">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Ibata</surname><given-names>R.</given-names></name><name><surname>Gilmore</surname><given-names>G.</given-names></name><name><surname>Irwin</surname><given-names>M.</given-names></name></person-group>, <year>1994</year>, <source>Nat</source>, <volume>370</volume>, <fpage>194</fpage></citation>
</ref>
<ref id="bib7">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Ibata</surname><given-names>R.</given-names></name><name><surname>Irwin</surname><given-names>M.</given-names></name><name><surname>Lewis</surname><given-names>G.</given-names></name><name><surname>Stolte</surname><given-names>A.</given-names></name></person-group>, <year>2001</year> <source>ApJ</source>, <volume>551</volume>, <fpage>294</fpage></citation>
</ref>
<ref id="bib8">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Ibata</surname><given-names>R.</given-names></name><name><surname>Irwin</surname><given-names>M.</given-names></name><name><surname>Lewis</surname><given-names>G.</given-names></name><name><surname>Ferguson</surname><given-names>A. M. N.</given-names></name><name><surname>Tanvir</surname><given-names>N.</given-names></name></person-group>, <year>2001</year> <source>Nat</source>, <volume>412</volume>, <fpage>49</fpage></citation>
</ref>
<ref id="bib9">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Irwin</surname><given-names>M.</given-names></name><name><surname>Lewis</surname><given-names>J.</given-names></name></person-group>, <year>2001</year>, <source>New Astron. Rev.</source>, <volume>45</volume>, <fpage>105</fpage></citation>
</ref>
<ref id="bib10">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Johnston</surname><given-names>K. V.</given-names></name><name><surname>Hernquist</surname><given-names>L.</given-names></name><name><surname>Bolte</surname><given-names>M.</given-names></name></person-group>, <year>1996</year>, <source>ApJ</source>, <volume>465</volume>, <fpage>278</fpage></citation>
</ref>
<ref id="bib11">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Quinn</surname><given-names>P. J.</given-names></name><name><surname>Hernquist</surname><given-names>L.</given-names></name><name><surname>Fullager</surname><given-names>D. P.</given-names></name></person-group>, <year>1993</year>, <source>ApJ</source>, <volume>403</volume>, <fpage>74</fpage></citation>
</ref>
<ref id="bib12">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Sagar</surname><given-names>R.</given-names></name><name><surname>Subramaniam</surname><given-names>A.</given-names></name><name><surname>Richtler</surname><given-names>T.</given-names></name><name><surname>Grebel</surname><given-names>E. K.</given-names></name></person-group>, <year>1999</year>, <source>A&AS</source>, <volume>135</volume>, <fpage>391</fpage></citation>
</ref>
<ref id="bib13">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Salaris</surname><given-names>M.</given-names></name><name><surname>Cassisi</surname><given-names>S.</given-names></name></person-group>, <year>1997</year>, <source>MNRAS</source>, <volume>289</volume>, <fpage>406</fpage></citation>
</ref>
<ref id="bib14">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Schlegel</surname><given-names>D. J.</given-names></name><name><surname>Finkbeiner</surname><given-names>D. P.</given-names></name><name><surname>Davis</surname><given-names>M.</given-names></name></person-group>, <year>1998</year>, <source>ApJ</source>, <volume>500</volume>, <fpage>525</fpage></citation>
</ref>
<ref id="bib15">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Schwarzkopf</surname><given-names>U.</given-names></name><name><surname>Dettmar</surname><given-names>R.-J.</given-names></name></person-group>, <year>2000</year>, <source>A&A</source>, <volume>361</volume>, <fpage>451</fpage></citation>
</ref>
<ref id="bib16">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>VandenBerg</surname><given-names>D. A.</given-names></name><name><surname>Swenson</surname><given-names>F. J.</given-names></name><name><surname>Rodgers</surname><given-names>F. J.</given-names></name><name><surname>Iglesias</surname><given-names>C. A.</given-names></name><name><surname>Alexander</surname><given-names>D. R.</given-names></name></person-group>, <year>2000</year>, <source>ApJ</source>, <volume>532</volume>, <fpage>430</fpage></citation>
</ref>
<ref id="bib17">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>Wheeler</surname><given-names>J. C.</given-names></name><name><surname>Sneden</surname><given-names>C.</given-names></name><name><surname>Truran</surname><given-names>J. W.</given-names></name></person-group>, <year>1989</year>, <source>ARA&A</source>, <volume>27</volume>, <fpage>279</fpage></citation>
</ref>
<ref id="bib18">
<citation citation-type="journal">
<person-group person-group-type="author"><name><surname>White</surname><given-names>S. D. M.</given-names></name><name><surname>Rees</surname><given-names>M. J.</given-names></name></person-group>, <year>1978</year>, <source>MNRAS</source>, <volume>183</volume>, <fpage>341</fpage></citation>
</ref>
</ref-list>
<fn-group>
<fn id="fn1" fn-type="other">
<label>1</label>
<p><ext-link ext-link-type="uri" xlink:href="http://www.cfht.hawaii.edu">http://www.cfht.hawaii.edu</ext-link></p>
</fn>
<fn id="fn2" fn-type="other">
<label>2</label>
<p><ext-link ext-link-type="uri" xlink:href="http://www.ast.cam.ac.uk/∼wfcsur/colours.php">http://www.ast.cam.ac.uk/∼wfcsur/colours.php</ext-link></p>
</fn>
</fn-group>
</back>
</article></istex:document></istex:metadataXml><mods version="3.6"><titleInfo><title>The three-dimensional structure of the giant stellar stream in Andromeda</title></titleInfo><titleInfo type="alternative" contentType="CDATA"><title>The three-dimensional structure of the giant stellar stream in Andromeda</title></titleInfo><name type="personal" displayLabel="corresp"><namePart type="given">A. W.</namePart><namePart type="family">McConnachie</namePart><affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</affiliation><affiliation>E-mail: alan@ast.cam.ac.uk</affiliation><affiliation></affiliation><affiliation>E-mail: alan@ast.cam.ac.uk</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">M. J.</namePart><namePart type="family">Irwin</namePart><affiliation>Institute of Astronomy, Madingley Road, Cambridge CB3 0HA</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">R. A.</namePart><namePart type="family">Ibata</namePart><affiliation>Observatoire de Strasbourg, 11, rue de l'Université, F-67000 Strasbourg, France</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">A. M. N.</namePart><namePart type="family">Ferguson</namePart><affiliation>Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching, Germany</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">G. F.</namePart><namePart type="family">Lewis</namePart><affiliation>Institute of Astronomy, School of Physics, A29, University of Sydney, NSW 2006, Australia</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">N.</namePart><namePart type="family">Tanvir</namePart><affiliation>Physical Sciences, University of Hertfordshire, Hatfield AL10 9AB</affiliation><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="research-article" displayLabel="research-article" authority="ISTEX" authorityURI="https://content-type.data.istex.fr" valueURI="https://content-type.data.istex.fr/ark:/67375/XTP-1JC4F85T-7">research-article</genre><originInfo><publisher>Blackwell Science Ltd</publisher><place><placeTerm type="text">Oxford, UK</placeTerm></place><dateIssued encoding="w3cdtf">2003-08-21</dateIssued><copyrightDate encoding="w3cdtf">2003</copyrightDate></originInfo><abstract>The wide-field CCD camera at the Canada–France–Hawaii Telescope (CFHT) was used to survey the giant stellar stream in the Andromeda galaxy, resolving stars down the red giant branch in M31 to I≃ 25, a magnitude deeper than our previous Isaac Newton Telescope (INT) survey of this galaxy and extending 1° further out. The stream is seen to extend out to the south-east of M31 as far as we have surveyed (some , corresponding to a projected distance of ∼60 kpc). It is a linear structure in projection, and the eastern edge of the stream presents a sharp boundary in star counts, suggesting that it remains a coherent structure. By analysing the luminosity function of the metal-rich component of the stream, we find that, at the furthest extent of our survey, the stream is 100 kpc further away along the line of sight than M31. It can then be traced to a point on the north-western side of the galaxy where it is some 30 kpc in front of M31, at which point the stream turns away from our survey area.</abstract><subject lang="en"><genre>Key words</genre><topic>galaxies: evolution</topic><topic>galaxies: general</topic><topic>galaxies: haloes</topic><topic>galaxies: interactions</topic><topic>Local Group</topic><topic>galaxies: stellar content</topic></subject><relatedItem type="host"><titleInfo><title>Monthly Notices of the Royal Astronomical Society</title></titleInfo><titleInfo type="abbreviated"><title>Mon. Not. R. Astron. Soc.</title></titleInfo><genre type="journal" authority="ISTEX" authorityURI="https://publication-type.data.istex.fr" valueURI="https://publication-type.data.istex.fr/ark:/67375/JMC-0GLKJH51-B">journal</genre><identifier type="ISSN">0035-8711</identifier><identifier type="eISSN">1365-2966</identifier><identifier type="PublisherID">mnras</identifier><identifier type="PublisherID-hwp">mnras</identifier><part><date>2003</date><detail type="volume"><caption>vol.</caption><number>343</number></detail><detail type="issue"><caption>no.</caption><number>4</number></detail><extent unit="pages"><start>1335</start><end>1340</end></extent></part></relatedItem><identifier type="istex">C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD</identifier><identifier type="DOI">10.1046/j.1365-8711.2003.06785.x</identifier><accessCondition type="use and reproduction" contentType="copyright">© 2003 RAS</accessCondition><recordInfo><recordContentSource authority="ISTEX" authorityURI="https://loaded-corpus.data.istex.fr" valueURI="https://loaded-corpus.data.istex.fr/ark:/67375/XBH-GTWS0RDP-M">oup</recordContentSource><recordOrigin>© 2003 RAS</recordOrigin></recordInfo></mods><json:item><extension>json</extension><original>false</original><mimetype>application/json</mimetype><uri>https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/metadata/json</uri></json:item></metadata><annexes><json:item><extension>jpeg</extension><original>true</original><mimetype>image/jpeg</mimetype><uri>https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/annexes/jpeg</uri></json:item><json:item><extension>gif</extension><original>true</original><mimetype>image/gif</mimetype><uri>https://api.istex.fr/document/C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD/annexes/gif</uri></json:item></annexes><serie></serie></istex></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Wicri/Asie/explor/AustralieFrV1/Data/Istex/Corpus
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 002391 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Istex/Corpus/biblio.hfd -nk 002391 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Wicri/Asie
|area= AustralieFrV1
|flux= Istex
|étape= Corpus
|type= RBID
|clé= ISTEX:C13D872EC53A9520F2A9D71F0B91EAF3F1F3F1BD
|texte= The three-dimensional structure of the giant stellar stream in Andromeda
}}
| This area was generated with Dilib version V0.6.33. |  |