Over 78 000 RR Lyrae Stars in the Galactic Bulge and Disk from the OGLE Survey

TL;DR

This paper reports an extensive upgrade to the OGLE collection of RR Lyrae stars, doubling the sample size to over 78,000, and provides detailed analysis of their distribution, types, and pulsation modes in the Galactic bulge and disk.

Contribution

The study significantly expands the OGLE RR Lyrae catalog and offers new insights into their spatial distribution and pulsation properties in the Milky Way.

Findings

Sample size of RR Lyrae stars doubled to 78,350.

Identification of new RRd stars with specific period ratios.

RR Lyrae distribution is roughly spherically symmetrical around the Galactic center.

Abstract

We present an upgrade of the OGLE Collection of RR Lyrae stars in the Galactic bulge and disk. The size of our sample has been doubled and reached 78 350 RR Lyr variables, of which 56 508 are fundamental-mode pulsators (RRab stars), 21 321 pulsate solely in the first-overtone (RRc stars), 458 are classical double-mode pulsators (RRd stars), and 63 are anomalous RRd variables (including five triple-mode pulsators). For all the newly identified RR Lyr stars, we publish time-series photometry obtained during the OGLE Galaxy Variability Survey. We present the spatial distribution of RR Lyr stars on the sky, provide a list of globular clusters hosting RR Lyr variables, and discuss the Petersen diagram for multimode pulsators. We find new RRd stars belonging to a compact group in the Petersen diagram (with period ratios P_1O/P_F = 0.74 and fundamental-mode periods P_F = 0.44 d) and we show that their spatial distribution is roughly spherically symmetrical around the Milky Way center.