J 2019

On the Oosterhoff dichotomy in the Galactic bulge - II. Kinematical distribution

PRUDIL, Zdeněk; Istvan DEKANY; E. K. GREBEL; Marcio CATELAN; Marek SKARKA et. al.

Basic information

Original name

On the Oosterhoff dichotomy in the Galactic bulge - II. Kinematical distribution

Authors

PRUDIL, Zdeněk (203 Czech Republic, guarantor); Istvan DEKANY; E. K. GREBEL; Marcio CATELAN; Marek SKARKA (203 Czech Republic, belonging to the institution) and R. SMOLEC

Edition

Monthly Notices of the Royal Astronomical Society, Oxford, OXFORD UNIV PRESS, 2019, 0035-8711

Other information

Language

English

Type of outcome

Article in a journal

Field of Study

10308 Astronomy

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

is not subject to a state or trade secret

References:

Impact factor

Impact factor: 5.357

RIV identification code

RIV/00216224:14310/19:00111910

Organization unit

Faculty of Science

UT WoS

000478053200024

EID Scopus

2-s2.0-85072277662

Keywords in English

stars: variables: RR Lyrae; Galaxy: bulge; Galaxy: kinematics and dynamics

Tags

Tags

International impact, Reviewed
Changed: 10/3/2020 10:28, Mgr. Marie Novosadová Šípková, DiS.

Abstract

V originále

We present a kinematical study of RR Lyrae stars associated with two Oosterhoff groups in the Galactic bulge, We used data published in the first paper of the series, plus proper motions from the Gaia Data Release 2, and radial velocities from the literature, A 6D kinematical and spatial solution was obtained for 429 RR Lyrae stars, We use a model of the Galactic gravitational potential to infer stellar orbits. We did not find a difference between the Oosterhoff groups in the individual components of the space velocity. We report that foreground and background stars with respect to the Galactic bulge stand out in the mean V velocity component, which we interpret as a sign of the Galactic rotation. The movement of the studied stars in the central region of the Galactic bulge is consistent with random motions expected for a classical bulge component. From the orbital integration, we estimate that 8 per cent of the RR Lyrae stars are halo interlopers currently located in the Galactic bulge. The majority of the stars' orbits are within a 3 kpc radius from the Galactic bulge. The fraction of Oosterhoff II stars increases with increasing Galactic latitude, as well as towards longer orbital periods. We found several RR Lyrae stars with high space velocities, one of which has an extremely long orbital period of similar to 1 Gyr. We conclude that based on their kinematics, the vast majority of the stars in our sample do not seem to contribute to the boxy/peanut component of the Galactic bulge.

Links

EF16_027/0008360, research and development project
Name: Postdoc@MUNI