2016/03/21 by Andrea Kunder, R. M. Rich, J. Storm +10 · 5 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Bulge #Kinematics #Luminosity #RR Lyrae variable #Radial velocity #Rotation (mathematics) #Stars #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.3847/2041-8205/821/2/l25
accepted to ApJL
arxiv created 2016/03/21 · openalex publication_date 2016/04/18 · arxiv updated 2016/04/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
ABSTRACT We present 947 radial velocities of RR Lyrae variable stars in four fields located toward the Galactic bulge, observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR). We show that these RR Lyrae stars (RRLs) exhibit hot kinematics and null or negligible rotation and are therefore members of a separate population from the bar/pseudobulge that currently dominates the mass and luminosity of the inner Galaxy. Our RRLs predate these structures and have metallicities, kinematics, and spatial distribution that are consistent with a “classical” bulge, although we cannot yet completely rule out the possibility that they are the metal-poor tail of a more metal-rich ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo stretchy="true">[</mml:mo> <mml:mi>Fe</mml:mi> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> <mml:mo stretchy="true">]</mml:mo> <mml:mo>∼</mml:mo> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:math> dex) halo–bulge population. The complete catalog of radial velocities for the BRAVA-RR stars is also published electronically.