Spectroscopic classification of X-ray sources in the Galactic Bulge Survey
arXiv:1705.10791 · doi:10.1093/mnras/stx1303
Abstract
We present the classification of 26 optical counterparts to X-ray sources discovered in the Galactic Bulge Survey. We use (time-resolved) photometric and spectroscopic observations to classify the X-ray sources based on their multi-wavelength properties. We find a variety of source classes, spanning different phases of stellar/binary evolution. We classify CX21 as a quiescent cataclysmic variable (CV) below the period gap, and CX118 as a high accretion rate (nova-like) CV. CXB12 displays excess UV emission, and could contain a compact object with a giant star companion, making it a candidate symbiotic binary or quiescent low mass X-ray binary (although other scenarios cannot be ruled out). CXB34 is a magnetic CV (polar) that shows photometric evidence for a change in accretion state. The magnetic classification is based on the detection of X-ray pulsations with a period of 81 2 min. CXB42 is identified as a young stellar object, namely a weak-lined T Tauri star exhibiting (to date unexplained) UX Ori-like photometric variability. The optical spectrum of CXB43 contains two (resolved) unidentified double-peaked emission lines. No known scenario, such as an AGN or symbiotic binary, can easily explain its characteristics. We additionally classify 20 objects as likely active stars based on optical spectroscopy, their X-ray to optical flux ratios and photometric variability. In 4 cases we identify the sources as binary stars.
Accepted for publication in MNRAS
References in corpus (12)
- The UKIDSS Galactic Plane Survey
- Intrinsically Red Sources observed by Spitzer in the Galactic Mid-Plane
- X-ray Emission from T Tauri Stars and the Role of Accretion: Inferences from the XMM-Newton Extended Survey of the Taurus Molecular Cloud
- Mapping the Milky Way bulge at high resolution: the 3D dust extinction, CO, and X factor maps
- SW Sextantis stars: the dominant population of CVs with orbital periods between 3-4 hours
- Spectroscopic search for new SW Sextantis stars in the 3-4 hour orbital period range -- I
- A Model for (Quasi-)Periodic Multi-wavelength Photometric Variability in Young Stellar Objects
- Discovery of a high state AM CVn binary in the Galactic Bulge Survey
- Variability of Optical Counterparts in the Chandra Galactic Bulge Survey
- Flows and Shocks: Some Recent Developments in Symbiotic Star and Nova Research
- Candidate Hα emission and absorption line sources in the Galactic Bulge Survey
- Gemini Spectroscopy of Galactic Bulge Sources: A Population of Hidden Accreting Binaries Revealed?