Origin of the high v_los feature in the Galactic bar
We analyse a controlled N-body + smoothed particle hydrodynamics simulation of a growing disc galaxy within a non-growing, live dark halo. The disc is continuously fed with gas and star particles on near-circular orbits and develops a bar comparable in size to the one of the Milky Way (MW). We extra...
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| Format: | Journal article |
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Oxford University Press
2015
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| _version_ | 1797051778872639488 |
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| author | Aumer, M Schönrich, R |
| author_facet | Aumer, M Schönrich, R |
| author_sort | Aumer, M |
| collection | OXFORD |
| description | We analyse a controlled N-body + smoothed particle hydrodynamics simulation of a growing disc galaxy within a non-growing, live dark halo. The disc is continuously fed with gas and star particles on near-circular orbits and develops a bar comparable in size to the one of the Milky Way (MW). We extract line of sight velocity v_los distributions from the model and compare it to data recently obtained from the APOGEE survey which show distinct high velocity features around v_los ~ 200 km/s. With an APOGEE like selection function, but without any scaling nor adjustment, we find v_los distributions very similar to those in APOGEE. The stars that make up the high v_los features at positive longitudes l are preferentially young bar stars (age <~ 2-3 Gyr) which move away from us along the rear side of the bar. At negative l, we find the corresponding low v_los feature from stars moving towards us. At l>10 degrees the highest v_los stars are a mixture of bar and background disc stars which complicates the interpretation of observations. The main peak in v_los is dominated by fore- and background stars. At a given time, ~40-50 per cent of high v_los stars occupy x_1 like orbits, but a significant fraction are on more complex orbits. The observed feature is likely due to a population of dynamically cool, young stars formed from gas just outside the bar and subsequently captured by the growing bar. The high v_los features disappear at high latitudes |b|>~2 degrees which explains the non-detection of such features in other surveys. |
| first_indexed | 2024-03-06T18:24:16Z |
| format | Journal article |
| id | oxford-uuid:0765dcf9-f12f-447a-be76-e192d3accf4f |
| institution | University of Oxford |
| last_indexed | 2024-03-06T18:24:16Z |
| publishDate | 2015 |
| publisher | Oxford University Press |
| record_format | dspace |
| spelling | oxford-uuid:0765dcf9-f12f-447a-be76-e192d3accf4f2022-03-26T09:07:18ZOrigin of the high v_los feature in the Galactic barJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:0765dcf9-f12f-447a-be76-e192d3accf4fSymplectic Elements at OxfordOxford University Press2015Aumer, MSchönrich, RWe analyse a controlled N-body + smoothed particle hydrodynamics simulation of a growing disc galaxy within a non-growing, live dark halo. The disc is continuously fed with gas and star particles on near-circular orbits and develops a bar comparable in size to the one of the Milky Way (MW). We extract line of sight velocity v_los distributions from the model and compare it to data recently obtained from the APOGEE survey which show distinct high velocity features around v_los ~ 200 km/s. With an APOGEE like selection function, but without any scaling nor adjustment, we find v_los distributions very similar to those in APOGEE. The stars that make up the high v_los features at positive longitudes l are preferentially young bar stars (age <~ 2-3 Gyr) which move away from us along the rear side of the bar. At negative l, we find the corresponding low v_los feature from stars moving towards us. At l>10 degrees the highest v_los stars are a mixture of bar and background disc stars which complicates the interpretation of observations. The main peak in v_los is dominated by fore- and background stars. At a given time, ~40-50 per cent of high v_los stars occupy x_1 like orbits, but a significant fraction are on more complex orbits. The observed feature is likely due to a population of dynamically cool, young stars formed from gas just outside the bar and subsequently captured by the growing bar. The high v_los features disappear at high latitudes |b|>~2 degrees which explains the non-detection of such features in other surveys. |
| spellingShingle | Aumer, M Schönrich, R Origin of the high v_los feature in the Galactic bar |
| title | Origin of the high v_los feature in the Galactic bar |
| title_full | Origin of the high v_los feature in the Galactic bar |
| title_fullStr | Origin of the high v_los feature in the Galactic bar |
| title_full_unstemmed | Origin of the high v_los feature in the Galactic bar |
| title_short | Origin of the high v_los feature in the Galactic bar |
| title_sort | origin of the high v los feature in the galactic bar |
| work_keys_str_mv | AT aumerm originofthehighvlosfeatureinthegalacticbar AT schonrichr originofthehighvlosfeatureinthegalacticbar |