RAPID INTRINSIC VARIABILITY OF SGR A* AT RADIO WAVELENGTHS
Identifieur interne : 006778 ( Main/Exploration ); précédent : 006777; suivant : 006779RAPID INTRINSIC VARIABILITY OF SGR A* AT RADIO WAVELENGTHS
Auteurs : F. Yusef-Zadeh [États-Unis] ; M. Wardle [Australie] ; J. C. A. Miller-Jones [États-Unis, Australie] ; D. A. Roberts [États-Unis] ; N. Grosso [France] ; D. Porquet [France]Source :
- The Astrophysical journal [ 0004-637X ] ; 2011.
Descripteurs français
- Pascal (Inist)
- Wicri :
- topic : Cosmologie.
English descriptors
- KwdEn :
Abstract
Sgr A* exhibits flares in radio, millimeter, and submillimeter wavelengths with durations of ˜1 hr. Using structure function, power spectrum, and autocorrelation function analysis, we investigate the variability of Sgr A* on timescales ranging from a few seconds to several hours and find evidence for subminute timescale variability at radio wavelengths. These measurements suggest a strong case for continuous variability from subminute to hourly timescales. This short timescale variability constrains the size of the emitting region to be less than 0.1 AU. Assuming that the minute timescale fluctuations of the emission at 7 mm arise through the expansion of regions of optically thick synchrotron-emitting plasma, this suggests the presence of explosive, energetic expansion events at speeds close to c. The required rates of mass processing and energy loss of this component are estimated to be ?6 x 10-10 M◦. yr-1 and 400 L◦., respectively. The inferred scale length corresponding to 1 minute light travel time is comparable to the time-averaged spatially resolved 0.1 AU scale observed at 1.3 mm emission of Sgr A*. This steady component from Sgr A* is interpreted mainly as an ensemble average of numerous weak and overlapping flares that are detected on short timescales. The nature of such short timescale variable emission or quiescent variability is not understood but could result from fluctuations in the accretion flow of Sgr A* that feed the base of an outflow or jet.
Affiliations:
- Australie, France, États-Unis
- Alsace (région administrative), Grand Est
- Strasbourg
- Université de Strasbourg
Links toward previous steps (curation, corpus...)
- to stream PascalFrancis, to step Corpus: 001F07
- to stream PascalFrancis, to step Curation: 004030
- to stream PascalFrancis, to step Checkpoint: 001736
- to stream Main, to step Merge: 006B87
- to stream Main, to step Curation: 006778
Le document en format XML
<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en" level="a">RAPID INTRINSIC VARIABILITY OF SGR A<sup>*</sup> AT RADIO WAVELENGTHS</title><author><name sortKey="Yusef Zadeh, F" sort="Yusef Zadeh, F" uniqKey="Yusef Zadeh F" first="F." last="Yusef-Zadeh">F. Yusef-Zadeh</name><affiliation wicri:level="1"><inist:fA14 i1="01"><s1>Department of Physics and Astronomy, Northwestern University</s1><s2>Evanston, IL 60208</s2><s3>USA</s3><sZ>1 aut.</sZ></inist:fA14><country>États-Unis</country><wicri:noRegion>Evanston, IL 60208</wicri:noRegion></affiliation></author><author><name sortKey="Wardle, M" sort="Wardle, M" uniqKey="Wardle M" first="M." last="Wardle">M. Wardle</name><affiliation wicri:level="1"><inist:fA14 i1="02"><s1>Department of Physics ad Astronomy, Macquarie University</s1><s2>Sydney NSW 2109</s2><s3>AUS</s3><sZ>2 aut.</sZ></inist:fA14><country>Australie</country><wicri:noRegion>Sydney NSW 2109</wicri:noRegion></affiliation></author><author><name sortKey="Miller Jones, J C A" sort="Miller Jones, J C A" uniqKey="Miller Jones J" first="J. C. A." last="Miller-Jones">J. C. A. Miller-Jones</name><affiliation wicri:level="1"><inist:fA14 i1="03"><s1>NRAO, Charlottesville, 520 Edgemont Road</s1><s2>VA 22903</s2><s3>USA</s3><sZ>3 aut.</sZ></inist:fA14><country>États-Unis</country><wicri:noRegion>VA 22903</wicri:noRegion></affiliation><affiliation wicri:level="1"><inist:fA14 i1="04"><s1>International Center for Radio Astronomy Research - Curtin University, GPO Box U1987</s1><s2>Perth, WA 6845</s2><s3>AUS</s3><sZ>3 aut.</sZ></inist:fA14><country>Australie</country><wicri:noRegion>Perth, WA 6845</wicri:noRegion></affiliation></author><author><name sortKey="Roberts, D A" sort="Roberts, D A" uniqKey="Roberts D" first="D. A." last="Roberts">D. A. Roberts</name><affiliation wicri:level="1"><inist:fA14 i1="05"><s1>Adler Planetarium & Astronomy Museum 1300 S. Lake Shore Drive</s1><s2>Chicago, IL 60605</s2><s3>USA</s3><sZ>4 aut.</sZ></inist:fA14><country>États-Unis</country><wicri:noRegion>Adler Planetarium & Astronomy Museum 1300 S. Lake Shore Drive</wicri:noRegion></affiliation></author><author><name sortKey="Grosso, N" sort="Grosso, N" uniqKey="Grosso N" first="N." last="Grosso">N. Grosso</name><affiliation wicri:level="4"><inist:fA14 i1="06"><s1>Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l'Université</s1><s2>67000 Strasbourg</s2><s3>FRA</s3><sZ>5 aut.</sZ><sZ>6 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><settlement type="city">Strasbourg</settlement></placeName><orgName type="university">Université de Strasbourg</orgName></affiliation></author><author><name sortKey="Porquet, D" sort="Porquet, D" uniqKey="Porquet D" first="D." last="Porquet">D. Porquet</name><affiliation wicri:level="4"><inist:fA14 i1="06"><s1>Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l'Université</s1><s2>67000 Strasbourg</s2><s3>FRA</s3><sZ>5 aut.</sZ><sZ>6 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><settlement type="city">Strasbourg</settlement></placeName><orgName type="university">Université de Strasbourg</orgName></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">INIST</idno><idno type="inist">11-0161185</idno><date when="2011">2011</date><idno type="stanalyst">PASCAL 11-0161185 INIST</idno><idno type="RBID">Pascal:11-0161185</idno><idno type="wicri:Area/PascalFrancis/Corpus">001F07</idno><idno type="wicri:Area/PascalFrancis/Curation">004030</idno><idno type="wicri:Area/PascalFrancis/Checkpoint">001736</idno><idno type="wicri:explorRef" wicri:stream="PascalFrancis" wicri:step="Checkpoint">001736</idno><idno type="wicri:doubleKey">0004-637X:2011:Yusef Zadeh F:rapid:intrinsic:variability</idno><idno type="wicri:Area/Main/Merge">006B87</idno><idno type="wicri:Area/Main/Curation">006778</idno><idno type="wicri:Area/Main/Exploration">006778</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a">RAPID INTRINSIC VARIABILITY OF SGR A<sup>*</sup> AT RADIO WAVELENGTHS</title><author><name sortKey="Yusef Zadeh, F" sort="Yusef Zadeh, F" uniqKey="Yusef Zadeh F" first="F." last="Yusef-Zadeh">F. Yusef-Zadeh</name><affiliation wicri:level="1"><inist:fA14 i1="01"><s1>Department of Physics and Astronomy, Northwestern University</s1><s2>Evanston, IL 60208</s2><s3>USA</s3><sZ>1 aut.</sZ></inist:fA14><country>États-Unis</country><wicri:noRegion>Evanston, IL 60208</wicri:noRegion></affiliation></author><author><name sortKey="Wardle, M" sort="Wardle, M" uniqKey="Wardle M" first="M." last="Wardle">M. Wardle</name><affiliation wicri:level="1"><inist:fA14 i1="02"><s1>Department of Physics ad Astronomy, Macquarie University</s1><s2>Sydney NSW 2109</s2><s3>AUS</s3><sZ>2 aut.</sZ></inist:fA14><country>Australie</country><wicri:noRegion>Sydney NSW 2109</wicri:noRegion></affiliation></author><author><name sortKey="Miller Jones, J C A" sort="Miller Jones, J C A" uniqKey="Miller Jones J" first="J. C. A." last="Miller-Jones">J. C. A. Miller-Jones</name><affiliation wicri:level="1"><inist:fA14 i1="03"><s1>NRAO, Charlottesville, 520 Edgemont Road</s1><s2>VA 22903</s2><s3>USA</s3><sZ>3 aut.</sZ></inist:fA14><country>États-Unis</country><wicri:noRegion>VA 22903</wicri:noRegion></affiliation><affiliation wicri:level="1"><inist:fA14 i1="04"><s1>International Center for Radio Astronomy Research - Curtin University, GPO Box U1987</s1><s2>Perth, WA 6845</s2><s3>AUS</s3><sZ>3 aut.</sZ></inist:fA14><country>Australie</country><wicri:noRegion>Perth, WA 6845</wicri:noRegion></affiliation></author><author><name sortKey="Roberts, D A" sort="Roberts, D A" uniqKey="Roberts D" first="D. A." last="Roberts">D. A. Roberts</name><affiliation wicri:level="1"><inist:fA14 i1="05"><s1>Adler Planetarium & Astronomy Museum 1300 S. Lake Shore Drive</s1><s2>Chicago, IL 60605</s2><s3>USA</s3><sZ>4 aut.</sZ></inist:fA14><country>États-Unis</country><wicri:noRegion>Adler Planetarium & Astronomy Museum 1300 S. Lake Shore Drive</wicri:noRegion></affiliation></author><author><name sortKey="Grosso, N" sort="Grosso, N" uniqKey="Grosso N" first="N." last="Grosso">N. Grosso</name><affiliation wicri:level="4"><inist:fA14 i1="06"><s1>Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l'Université</s1><s2>67000 Strasbourg</s2><s3>FRA</s3><sZ>5 aut.</sZ><sZ>6 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><settlement type="city">Strasbourg</settlement></placeName><orgName type="university">Université de Strasbourg</orgName></affiliation></author><author><name sortKey="Porquet, D" sort="Porquet, D" uniqKey="Porquet D" first="D." last="Porquet">D. Porquet</name><affiliation wicri:level="4"><inist:fA14 i1="06"><s1>Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l'Université</s1><s2>67000 Strasbourg</s2><s3>FRA</s3><sZ>5 aut.</sZ><sZ>6 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><settlement type="city">Strasbourg</settlement></placeName><orgName type="university">Université de Strasbourg</orgName></affiliation></author></analytic><series><title level="j" type="main">The Astrophysical journal</title><title level="j" type="abbreviated">Astrophys. j.</title><idno type="ISSN">0004-637X</idno><imprint><date when="2011">2011</date></imprint></series></biblStruct></sourceDesc><seriesStmt><title level="j" type="main">The Astrophysical journal</title><title level="j" type="abbreviated">Astrophys. j.</title><idno type="ISSN">0004-637X</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Accretion</term><term>Accretion disks</term><term>Autocorrelation function</term><term>Black holes</term><term>Cosmology</term><term>Energetics</term><term>Energy losses</term><term>Fluctuations</term><term>Galaxies</term><term>Jets</term><term>Plasma</term><term>Power spectra</term><term>Structure functions</term><term>Travel time</term><term>Variability</term></keywords><keywords scheme="Pascal" xml:lang="fr"><term>Variabilité</term><term>Fonction structure</term><term>Spectre puissance</term><term>Fonction autocorrélation</term><term>Fluctuation</term><term>Plasma</term><term>Energétique</term><term>Perte énergie</term><term>Durée trajet</term><term>Accrétion</term><term>Jet</term><term>Disque accrétion</term><term>Trou noir</term><term>Galaxies</term><term>Cosmologie</term></keywords><keywords scheme="Wicri" type="topic" xml:lang="fr"><term>Cosmologie</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">Sgr A* exhibits flares in radio, millimeter, and submillimeter wavelengths with durations of ˜1 hr. Using structure function, power spectrum, and autocorrelation function analysis, we investigate the variability of Sgr A* on timescales ranging from a few seconds to several hours and find evidence for subminute timescale variability at radio wavelengths. These measurements suggest a strong case for continuous variability from subminute to hourly timescales. This short timescale variability constrains the size of the emitting region to be less than 0.1 AU. Assuming that the minute timescale fluctuations of the emission at 7 mm arise through the expansion of regions of optically thick synchrotron-emitting plasma, this suggests the presence of explosive, energetic expansion events at speeds close to c. The required rates of mass processing and energy loss of this component are estimated to be ?6 x 10<sup>-10</sup> M<sub>◦.</sub> yr<sup>-1</sup> and 400 L<sub>◦.</sub>, respectively. The inferred scale length corresponding to 1 minute light travel time is comparable to the time-averaged spatially resolved 0.1 AU scale observed at 1.3 mm emission of Sgr A<sup>*</sup>. This steady component from Sgr A<sup>*</sup> is interpreted mainly as an ensemble average of numerous weak and overlapping flares that are detected on short timescales. The nature of such short timescale variable emission or quiescent variability is not understood but could result from fluctuations in the accretion flow of Sgr A* that feed the base of an outflow or jet.</div></front></TEI><affiliations><list><country><li>Australie</li><li>France</li><li>États-Unis</li></country><region><li>Alsace (région administrative)</li><li>Grand Est</li></region><settlement><li>Strasbourg</li></settlement><orgName><li>Université de Strasbourg</li></orgName></list><tree><country name="États-Unis"><noRegion><name sortKey="Yusef Zadeh, F" sort="Yusef Zadeh, F" uniqKey="Yusef Zadeh F" first="F." last="Yusef-Zadeh">F. Yusef-Zadeh</name></noRegion><name sortKey="Miller Jones, J C A" sort="Miller Jones, J C A" uniqKey="Miller Jones J" first="J. C. A." last="Miller-Jones">J. C. A. Miller-Jones</name><name sortKey="Roberts, D A" sort="Roberts, D A" uniqKey="Roberts D" first="D. A." last="Roberts">D. A. Roberts</name></country><country name="Australie"><noRegion><name sortKey="Wardle, M" sort="Wardle, M" uniqKey="Wardle M" first="M." last="Wardle">M. Wardle</name></noRegion><name sortKey="Miller Jones, J C A" sort="Miller Jones, J C A" uniqKey="Miller Jones J" first="J. C. A." last="Miller-Jones">J. C. A. Miller-Jones</name></country><country name="France"><region name="Grand Est"><name sortKey="Grosso, N" sort="Grosso, N" uniqKey="Grosso N" first="N." last="Grosso">N. Grosso</name></region><name sortKey="Porquet, D" sort="Porquet, D" uniqKey="Porquet D" first="D." last="Porquet">D. Porquet</name></country></tree></affiliations></record>Pour manipuler ce document sous Unix (Dilib)
EXPLOR_STEP=$WICRI_ROOT/Wicri/Asie/explor/AustralieFrV1/Data/Main/Exploration
HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 006778 | SxmlIndent | more
Ou
HfdSelect -h $EXPLOR_AREA/Data/Main/Exploration/biblio.hfd -nk 006778 | SxmlIndent | more
Pour mettre un lien sur cette page dans le réseau Wicri
{{Explor lien
|wiki= Wicri/Asie
|area= AustralieFrV1
|flux= Main
|étape= Exploration
|type= RBID
|clé= Pascal:11-0161185
|texte= RAPID INTRINSIC VARIABILITY OF SGR A* AT RADIO WAVELENGTHS
}}
| This area was generated with Dilib version V0.6.33. |  |