XMM-Newton and optical follow-up observations of SDSS J093249.57+472523.0 and SDSS J102347.67+003841.2

Abstract

We report follow-up XMM-Newton and ground-based optical observations of the unusual X-ray binary SDSS J102347.67+003841.2 (=FIRST J102347.6+003841), and a new candidate intermediate polar found in the Sloan Digital Sky Survey: SDSS J093249.57+472523.0. SDSS J1023 was observed in its low-state, with similar magnitude/color (V=17.4 and B=17.9), and smooth orbital modulation as seen in most previous observations. We further refine the ephemeris (for photometric minimum) to: HJD(TT)_min= 2453081.8546(3) + E* 0.198094(1) d. It is easily detected in X-rays at an unabsorbed flux (0.01-10.0 keV) of 5x10e-13 erg/cm^2/s. Fitting a variety of models we find that: (i) either a hot (kT>~15 keV) optically thin plasma emission model (bremsstrahlung or MEKAL) or a simple power law can provide adequate fits to the data; (ii) these models prefer a low column density ~10e19 cm^-2; (iii) a neutron star atmosphere plus power law model (as found for quiescent low-mass X-ray binaries) can also produce a good fit (for plausible distances), though only for a much higher column of about 4x10e20 cm^-2 and a very cool atmosphere kT<~50eV. These results support the case that SDSS J1023 is a transient LMXB, and indeed places it in the subclass of such systems whose quiescent X-ray emission is dominated by a hard power law component. Our optical photometry of SDSS J0932 reveals that it is an high inclination eclipsing system. Combined with its optical characteristics -- high excitation emission lines, and brightness, yielding a large F_X/F_opt ratio -- its highly absorbed X-ray spectrum argues that SDSS J0932 is a strong IP candidate. However, only more extensive optical photometry and a detection of its spin or spin-orbit beat frequency can confirm this classification. (abridged)

arXiv comment9 pages, 7 figures, accepted for publication in the Astronomical Journal (page formatting corrected)

References in corpus (15)

• The Sloan Digital Sky Survey: Technical Summary
• The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
• The Neutron Stars of Soft X-Ray Transients
• A Deep Chandra Survey of the Globular Cluster 47 Tucanae: Catalog of Point Sources
• Cataclysmic Variables from SDSS II. The Second Year
• Is FIRST J102347.6+003841 Really a Cataclysmic Binary?
• Optical and X-ray observations of the neutron star soft X-ray transient XTE J1709-267
• The Optical Counterpart to SAX J1808.4-3658 in Quiescence: Evidence of an Active Radio Pulsar?
• High speed photometry of faint Cataclysmic Variables: IV. V356 Aql, Aqr1, FIRST J1023+0038, Ha 0242-2802, GI Mon, AO Oct, V972 Oph, SDSS 0155+00, SDSS 0233+00, SDSS 1240-01, SDSS 1556-00, SDSS 2050-05, FH Ser
• FIRST J102347.6+003841: The First Radio-Selected Cataclysmic Variable
• The hard quiescent spectrum of the neutron-star X-ray transient EXO 1745-248 in the globular cluster Terzan 5
• The variable quiescence of Cen X-4
• The faint neutron star soft X-ray transient SAX J1810.8-2609 in quiescence
• The emission regions in X-ray binaries: dipping as a diagnostic
• New results on neutron star low mass transients in the quiescence

Cited by in corpus (28)

• A Radio Pulsar/X-ray Binary Link
• SDSS unveils a population of intrinsically faint cataclysmic variables at the minimum orbital period
• A state change in the missing link binary pulsar system PSR J1023+0038
• A New Accretion Disk Around the Missing Link Binary System PSR J1023+0038
• A Chandra X-ray Observation of the Binary Millisecond Pulsar PSR J1023+0038
• X-ray Variability and Evidence for Pulsations from the Unique Radio Pulsar/X-ray Binary Transition Object FIRST J102347.6+003841
• Multi-wavelength emissions from the millisecond pulsar binary PSR J1023+0038 during an accretion active state
• The Accreting Millisecond X-ray Pulsar IGR J00291+5934: Evidence for a Long Timescale Spin Evolution
• Evidence for reduced magnetic braking in polars from binary population models
• Transitional millisecond pulsars
• Long-term observations of the pulsars in 47 Tucanae. I. A study of four elusive binary systems
• NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038
• SDSS J102347.6+003841: A Millisecond Radio Pulsar Binary That Had A Hot Disk During 2000-2001
• A Chandra X-ray Observatory Study of PSR J1740--5340 and Candidate Millisecond Pulsars in the Globular Cluster NGC 6397
• A catalogue of cataclysmic variables from 20 years of the Sloan Digital Sky Survey with new classifications, periods, trends and oddities
• Engulfing a radio pulsar: the case of PSR J1023+0038
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. III: The Third Year (2010--2011)
• Evidence for gamma-ray emission from the low-mass X-ray binary system FIRST J102347.6+003841
• X-ray Census of Millisecond Pulsars in the Galactic field
• NuSTAR observations and broadband spectral energy distribution modeling of the millisecond pulsar binary PSR J1023+0038
• Roche Lobe Underfilling of the Secondary Star in PSR J102347.6+003841?
• New possible class of neutron stars: hot and fast non-accreting rotators
• The binary millisecond pulsar PSR J1023+0038 -- II. Optical spectroscopy
• On the Transition from Accretion Powered to Rotation Powered Millisecond Pulsars
• Observational signatures of neutron stars in low-mass X-ray binaries climbing a stability peak
• A Search for Very High-Energy Gamma Rays from the Missing Link Binary Pulsar J1023+0038 with VERITAS
• Infrared Observations of The Millisecond Pulsar Binary J1023+0038: Evidence for Short-Term Nature of Its Interacting Phase in 2000--2001
• There and back again: Mysterious optical pulse profile behavior of the transitional millisecond pulsar PSR J1023+0038