Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda Galaxy
The total mass of a galaxy group, such as the Milky Way (MW) and the Andromeda Galaxy (M 31), is typically determined from the kinematics of satellites within their virial zones. Bahcall and Tremaine (1981) proposed the <i>v</i><sup>2</sup><i>r</i> estimator as an...
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| author | Danila Makarov Dmitry Makarov Kirill Kozyrev Noam Libeskind |
| author_facet | Danila Makarov Dmitry Makarov Kirill Kozyrev Noam Libeskind |
| author_sort | Danila Makarov |
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| description | The total mass of a galaxy group, such as the Milky Way (MW) and the Andromeda Galaxy (M 31), is typically determined from the kinematics of satellites within their virial zones. Bahcall and Tremaine (1981) proposed the <i>v</i><sup>2</sup><i>r</i> estimator as an alternative to the virial theorem. In this work, we extend their approach by incorporating the three-dimensional spatial distribution of satellites within the system to improve the reliability and accuracy of galaxy mass estimates. Applying this method to a comprehensive dataset of local group satellites based on recent, high-precision distance measurements, we estimate the total mass of the MW to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>(</mo><mn>7.9</mn><mo>±</mo><mn>2.3</mn><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mn>11</mn></msup></mrow></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>M</mi><mo>⊙</mo></msub></semantics></math></inline-formula> and that of M 31 to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>(</mo><mn>15.5</mn><mo>±</mo><mn>3.4</mn><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mn>11</mn></msup></mrow></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>M</mi><mo>⊙</mo></msub></semantics></math></inline-formula>. The effectiveness of the method is constrained by the precision of distance measurements, making it particularly well suited for the local group, but challenging to apply to more distant systems. |
| format | Article |
| id | doaj-art-3c78d4e781284d818616e2fb9719ebff |
| institution | OA Journals |
| issn | 2218-1997 |
| language | English |
| publishDate | 2025-04-01 |
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| spelling | doaj-art-3c78d4e781284d818616e2fb9719ebff2025-08-20T02:33:58ZengMDPI AGUniverse2218-19972025-04-0111514410.3390/universe11050144Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda GalaxyDanila Makarov0Dmitry Makarov1Kirill Kozyrev2Noam Libeskind3Special Astrophysical Observatory, Russian Academy of Sciences, 369167 Nizhnij Arkhyz, RussiaSpecial Astrophysical Observatory, Russian Academy of Sciences, 369167 Nizhnij Arkhyz, RussiaSpecial Astrophysical Observatory, Russian Academy of Sciences, 369167 Nizhnij Arkhyz, RussiaLeibniz Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, GermanyThe total mass of a galaxy group, such as the Milky Way (MW) and the Andromeda Galaxy (M 31), is typically determined from the kinematics of satellites within their virial zones. Bahcall and Tremaine (1981) proposed the <i>v</i><sup>2</sup><i>r</i> estimator as an alternative to the virial theorem. In this work, we extend their approach by incorporating the three-dimensional spatial distribution of satellites within the system to improve the reliability and accuracy of galaxy mass estimates. Applying this method to a comprehensive dataset of local group satellites based on recent, high-precision distance measurements, we estimate the total mass of the MW to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>(</mo><mn>7.9</mn><mo>±</mo><mn>2.3</mn><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mn>11</mn></msup></mrow></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>M</mi><mo>⊙</mo></msub></semantics></math></inline-formula> and that of M 31 to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>(</mo><mn>15.5</mn><mo>±</mo><mn>3.4</mn><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mn>11</mn></msup></mrow></semantics></math></inline-formula> <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>M</mi><mo>⊙</mo></msub></semantics></math></inline-formula>. The effectiveness of the method is constrained by the precision of distance measurements, making it particularly well suited for the local group, but challenging to apply to more distant systems.https://www.mdpi.com/2218-1997/11/5/144local groupAndromeda GalaxyMilky Waydark matter |
| spellingShingle | Danila Makarov Dmitry Makarov Kirill Kozyrev Noam Libeskind Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda Galaxy Universe local group Andromeda Galaxy Milky Way dark matter |
| title | Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda Galaxy |
| title_full | Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda Galaxy |
| title_fullStr | Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda Galaxy |
| title_full_unstemmed | Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda Galaxy |
| title_short | Line-of-Sight Mass Estimator and the Masses of the Milky Way and Andromeda Galaxy |
| title_sort | line of sight mass estimator and the masses of the milky way and andromeda galaxy |
| topic | local group Andromeda Galaxy Milky Way dark matter |
| url | https://www.mdpi.com/2218-1997/11/5/144 |
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