The Galactic Bulge exploration IV.: RR~Lyrae stars as traces of the Galactic bar -- 3D and 5D analysis, extinction variation
Fuente:
arXiv
Enregistré dans:
| Auteurs principaux: | , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Publié: |
2025
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866910891286462464 |
|---|---|
| author | Prudil, Z. Kunder, A. Silva, L. Beraldo e Gough-Kelly, S. Rejkuba, M. Anderson, S. R. Debattista, V. P. Gerhard, O. Rich, R. M. Nataf, D. M. Koch-Hansen, A. J. Savino, A. Dékány, I. |
| author_facet | Prudil, Z. Kunder, A. Silva, L. Beraldo e Gough-Kelly, S. Rejkuba, M. Anderson, S. R. Debattista, V. P. Gerhard, O. Rich, R. M. Nataf, D. M. Koch-Hansen, A. J. Savino, A. Dékány, I. |
| contents | We created new reddening maps and derived new extinction laws from visual to near-infrared passbands using improved RR~Lyrae period-absolute magnitude-metallicity relations, thus enabling distance estimates for individual bulge RR~Lyrae variables. The extinction law is most uniform in RIK and RJK and the distances to individual RR~Lyrae based on these colors are determined with an accuracy six and four percent, respectively. Using only the near-infrared passbands for distance estimation we inferred the distance to the Galactic center equal to djk = 8.2 +- 0.001(stat) +- 0.53(sys)pc after geometrical correction. We show that variations in the extinction law toward the Galactic bulge can mimic a barred spatial distribution in the bulge RR~Lyrae star population in visual passbands. This arises from a gradient in extinction differences along Galactic longitudes and latitudes, which can create the perception of the Galactic bar, particularly when using visual passband-based distances. A barred angle in the RR~Lyrae spatial distribution disappears when near-infrared passband-based distances are used, as well as when reddening law variations are incorporated in visual passband-based distances. The prominence of the bar, as traced by RR~Lyrae stars, depends on their metallicity, with metal-poor RR~Lyrae stars ([Fe/H]<-1.0dex) showing little to no tilt with respect to the bar. Metal-rich ([Fe/H]>-1.0dex) RR~Lyrae stars do show a barred/bulge signature in spatial properties derived using near-infrared distances, with an angle ι = 18 +- 5deg, consistent with previous bar measurements from the literature. The 5D kinematic analysis, primarily based on transverse velocities, indicates a rotational lag in RR~Lyrae stars compared to red clump giants. Despite variations in the extinction law, our kinematic conclusions are robust across different distance estimation methods. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_03497 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The Galactic Bulge exploration IV.: RR~Lyrae stars as traces of the Galactic bar -- 3D and 5D analysis, extinction variation Prudil, Z. Kunder, A. Silva, L. Beraldo e Gough-Kelly, S. Rejkuba, M. Anderson, S. R. Debattista, V. P. Gerhard, O. Rich, R. M. Nataf, D. M. Koch-Hansen, A. J. Savino, A. Dékány, I. Astrophysics of Galaxies Solar and Stellar Astrophysics We created new reddening maps and derived new extinction laws from visual to near-infrared passbands using improved RR~Lyrae period-absolute magnitude-metallicity relations, thus enabling distance estimates for individual bulge RR~Lyrae variables. The extinction law is most uniform in RIK and RJK and the distances to individual RR~Lyrae based on these colors are determined with an accuracy six and four percent, respectively. Using only the near-infrared passbands for distance estimation we inferred the distance to the Galactic center equal to djk = 8.2 +- 0.001(stat) +- 0.53(sys)pc after geometrical correction. We show that variations in the extinction law toward the Galactic bulge can mimic a barred spatial distribution in the bulge RR~Lyrae star population in visual passbands. This arises from a gradient in extinction differences along Galactic longitudes and latitudes, which can create the perception of the Galactic bar, particularly when using visual passband-based distances. A barred angle in the RR~Lyrae spatial distribution disappears when near-infrared passband-based distances are used, as well as when reddening law variations are incorporated in visual passband-based distances. The prominence of the bar, as traced by RR~Lyrae stars, depends on their metallicity, with metal-poor RR~Lyrae stars ([Fe/H]<-1.0dex) showing little to no tilt with respect to the bar. Metal-rich ([Fe/H]>-1.0dex) RR~Lyrae stars do show a barred/bulge signature in spatial properties derived using near-infrared distances, with an angle ι = 18 +- 5deg, consistent with previous bar measurements from the literature. The 5D kinematic analysis, primarily based on transverse velocities, indicates a rotational lag in RR~Lyrae stars compared to red clump giants. Despite variations in the extinction law, our kinematic conclusions are robust across different distance estimation methods. |
| title | The Galactic Bulge exploration IV.: RR~Lyrae stars as traces of the Galactic bar -- 3D and 5D analysis, extinction variation |
| topic | Astrophysics of Galaxies Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2501.03497 |