Chemically Dissected Rotation Curves of the Galactic Bulge from Main-sequence Proper Motions

William I. Clarkson, Annalisa Calamida, Kailash C. Sahu, Thomas M. Brown, Mario Gennaro, Roberto J. Avila, Jeff Valenti, Victor P. Debattista, R. Michael Rich, Dante Minniti, Manuela Zoccali, Emily R. Aufdemberge

Resultado de la investigación: Article

5 Citas (Scopus)

Resumen

We report results from an exploratory study implementing a new probe of Galactic evolution using archival Hubble Space Telescope imaging observations. Precise proper motions are combined with photometric relative metallicity and temperature indices, to produce the proper-motion rotation curves of the Galactic bulge separately for metal-poor and metal-rich main-sequence samples. This provides a "pencil-beam" complement to large-scale wide-field surveys, which to date have focused on the more traditional bright giant branch tracers. We find strong evidence that the Galactic bulge rotation curves drawn from "metal-rich" and "metal-poor" samples are indeed discrepant. The "metal-rich" sample shows greater rotation amplitude and a steeper gradient against line-of-sight distance, as well as possibly a stronger central concentration along the line of sight. This may represent a new detection of differing orbital anisotropy between metal-rich and metal-poor bulge objects. We also investigate selection effects that would be implied for the longitudinal proper-motion cut often used to isolate a "pure-bulge" sample. Extensive investigation of synthetic stellar populations suggests that instrumental and observational artifacts are unlikely to account for the observed rotation curve differences. Thus, proper-motion-based rotation curves can be used to probe chemodynamical correlations for main-sequence tracer stars, which are orders of magnitude more numerous in the Galactic bulge than the bright giant branch tracers. We discuss briefly the prospect of using this new tool to constrain detailed models of Galactic formation and evolution.

Idioma originalEnglish
Número de artículo46
PublicaciónAstrophysical Journal
Volumen858
N.º1
DOI
EstadoPublished - 1 may 2018

Huella dactilar

galactic bulge
proper motion
metal
curves
metals
tracers
tracer
line of sight
probe
pencil beams
probes
galactic evolution
Hubble Space Telescope
complement
field survey
metallicity
artifact
artifacts
anisotropy
stars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Clarkson, W. I., Calamida, A., Sahu, K. C., Brown, T. M., Gennaro, M., Avila, R. J., ... Aufdemberge, E. R. (2018). Chemically Dissected Rotation Curves of the Galactic Bulge from Main-sequence Proper Motions. Astrophysical Journal, 858(1), [46]. https://doi.org/10.3847/1538-4357/aaba7f
Clarkson, William I. ; Calamida, Annalisa ; Sahu, Kailash C. ; Brown, Thomas M. ; Gennaro, Mario ; Avila, Roberto J. ; Valenti, Jeff ; Debattista, Victor P. ; Rich, R. Michael ; Minniti, Dante ; Zoccali, Manuela ; Aufdemberge, Emily R. / Chemically Dissected Rotation Curves of the Galactic Bulge from Main-sequence Proper Motions. En: Astrophysical Journal. 2018 ; Vol. 858, N.º 1.
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abstract = "We report results from an exploratory study implementing a new probe of Galactic evolution using archival Hubble Space Telescope imaging observations. Precise proper motions are combined with photometric relative metallicity and temperature indices, to produce the proper-motion rotation curves of the Galactic bulge separately for metal-poor and metal-rich main-sequence samples. This provides a {"}pencil-beam{"} complement to large-scale wide-field surveys, which to date have focused on the more traditional bright giant branch tracers. We find strong evidence that the Galactic bulge rotation curves drawn from {"}metal-rich{"} and {"}metal-poor{"} samples are indeed discrepant. The {"}metal-rich{"} sample shows greater rotation amplitude and a steeper gradient against line-of-sight distance, as well as possibly a stronger central concentration along the line of sight. This may represent a new detection of differing orbital anisotropy between metal-rich and metal-poor bulge objects. We also investigate selection effects that would be implied for the longitudinal proper-motion cut often used to isolate a {"}pure-bulge{"} sample. Extensive investigation of synthetic stellar populations suggests that instrumental and observational artifacts are unlikely to account for the observed rotation curve differences. Thus, proper-motion-based rotation curves can be used to probe chemodynamical correlations for main-sequence tracer stars, which are orders of magnitude more numerous in the Galactic bulge than the bright giant branch tracers. We discuss briefly the prospect of using this new tool to constrain detailed models of Galactic formation and evolution.",
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Clarkson, WI, Calamida, A, Sahu, KC, Brown, TM, Gennaro, M, Avila, RJ, Valenti, J, Debattista, VP, Rich, RM, Minniti, D, Zoccali, M & Aufdemberge, ER 2018, 'Chemically Dissected Rotation Curves of the Galactic Bulge from Main-sequence Proper Motions', Astrophysical Journal, vol. 858, n.º 1, 46. https://doi.org/10.3847/1538-4357/aaba7f

Chemically Dissected Rotation Curves of the Galactic Bulge from Main-sequence Proper Motions. / Clarkson, William I.; Calamida, Annalisa; Sahu, Kailash C.; Brown, Thomas M.; Gennaro, Mario; Avila, Roberto J.; Valenti, Jeff; Debattista, Victor P.; Rich, R. Michael; Minniti, Dante; Zoccali, Manuela; Aufdemberge, Emily R.

En: Astrophysical Journal, Vol. 858, N.º 1, 46, 01.05.2018.

Resultado de la investigación: Article

TY - JOUR

T1 - Chemically Dissected Rotation Curves of the Galactic Bulge from Main-sequence Proper Motions

AU - Clarkson, William I.

AU - Calamida, Annalisa

AU - Sahu, Kailash C.

AU - Brown, Thomas M.

AU - Gennaro, Mario

AU - Avila, Roberto J.

AU - Valenti, Jeff

AU - Debattista, Victor P.

AU - Rich, R. Michael

AU - Minniti, Dante

AU - Zoccali, Manuela

AU - Aufdemberge, Emily R.

PY - 2018/5/1

Y1 - 2018/5/1

N2 - We report results from an exploratory study implementing a new probe of Galactic evolution using archival Hubble Space Telescope imaging observations. Precise proper motions are combined with photometric relative metallicity and temperature indices, to produce the proper-motion rotation curves of the Galactic bulge separately for metal-poor and metal-rich main-sequence samples. This provides a "pencil-beam" complement to large-scale wide-field surveys, which to date have focused on the more traditional bright giant branch tracers. We find strong evidence that the Galactic bulge rotation curves drawn from "metal-rich" and "metal-poor" samples are indeed discrepant. The "metal-rich" sample shows greater rotation amplitude and a steeper gradient against line-of-sight distance, as well as possibly a stronger central concentration along the line of sight. This may represent a new detection of differing orbital anisotropy between metal-rich and metal-poor bulge objects. We also investigate selection effects that would be implied for the longitudinal proper-motion cut often used to isolate a "pure-bulge" sample. Extensive investigation of synthetic stellar populations suggests that instrumental and observational artifacts are unlikely to account for the observed rotation curve differences. Thus, proper-motion-based rotation curves can be used to probe chemodynamical correlations for main-sequence tracer stars, which are orders of magnitude more numerous in the Galactic bulge than the bright giant branch tracers. We discuss briefly the prospect of using this new tool to constrain detailed models of Galactic formation and evolution.

AB - We report results from an exploratory study implementing a new probe of Galactic evolution using archival Hubble Space Telescope imaging observations. Precise proper motions are combined with photometric relative metallicity and temperature indices, to produce the proper-motion rotation curves of the Galactic bulge separately for metal-poor and metal-rich main-sequence samples. This provides a "pencil-beam" complement to large-scale wide-field surveys, which to date have focused on the more traditional bright giant branch tracers. We find strong evidence that the Galactic bulge rotation curves drawn from "metal-rich" and "metal-poor" samples are indeed discrepant. The "metal-rich" sample shows greater rotation amplitude and a steeper gradient against line-of-sight distance, as well as possibly a stronger central concentration along the line of sight. This may represent a new detection of differing orbital anisotropy between metal-rich and metal-poor bulge objects. We also investigate selection effects that would be implied for the longitudinal proper-motion cut often used to isolate a "pure-bulge" sample. Extensive investigation of synthetic stellar populations suggests that instrumental and observational artifacts are unlikely to account for the observed rotation curve differences. Thus, proper-motion-based rotation curves can be used to probe chemodynamical correlations for main-sequence tracer stars, which are orders of magnitude more numerous in the Galactic bulge than the bright giant branch tracers. We discuss briefly the prospect of using this new tool to constrain detailed models of Galactic formation and evolution.

KW - Galaxy: bulge

KW - Galaxy: disk

KW - Galaxy: kinematics and dynamics

KW - instrumentation: high angular resolution

KW - methods: data analysis

KW - techniques: photometric

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