The mass of the black hole in 1A 0620-00, revisiting the ellipsoidal light curve modeling

Abstract

The mass distribution of stellar mass black holes can provide important clues to supernova modeling, but observationally it is still ill constrained. Therefore it is of importance to make black hole mass measurements as accurate as possible. The X-ray transient 1A 0620-00 is well studied, with a published black hole mass of $6.61\pm 0.25$M${}_{\odot }$, based on an orbital inclination $i$ of $51.0\pm 0.9$ degrees. This was obtained by Cantrell et al. (2010), as an average of independent fits to $V$-, $I$- and $H$-band light curves. In this work we perform an independent check on the value of $i$ by re-analyzing existing YALO/SMARTS $V$-, $I$- and $H$-band photometry, using different modeling software and fitting strategy. Performing a fit to the three light curves simultaneously, we obtain a value for $i$ of $54.1\pm 1.1$ degrees, resulting in a black hole mass of $5.86\pm 0.24$M${}_{\odot }$. Applying the same model to the light curves individually, we obtain $58.2\pm 1.9$, $53.6\pm 1.6$ and $50.5\pm 2.2$ degrees for $V$-, $I$- and $H$-band, respectively, where the differences in best-fitting $i$ are caused by the contribution of the residual accretion disc light in the three different bands. We conclude that the mass determination of this black hole may still be subject to systematic effects exceeding the statistical uncertainty. Obtaining more accurate masses would be greatly helped by continuous phase-resolved spectroscopic observations simultaneous with photometry.

9 pages, 5 figures, 2 tables, accepted for publication in MNRAS

References in corpus (3)

• A radio-emitting outflow in the quiescent state of A0620-00: implications for modelling low-luminosity black hole binaries
• Comprehensive simulations of superhumps
• The Eccentric Accretion Disc of the Black Hole A0620-00

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• A correlation between Ha trough depth and inclination in quiescent X-ray transients: evidence for a low-mass black hole in GRO J0422+32
• ALMA observations of A0620-00: fresh clues on the nature of quiescent black hole X-ray binary jets
• The Disk Veiling Effect of the Black Hole Low-Mass X-ray Binary A0620-00
• Scale-invariance of black hole accretion: modeling emission from a black hole X-ray binary with relativistic accretion flow simulations
• WIMP constraints from black hole low-mass X-ray binaries
• The orbital period and inclination of the neutron star X-ray transient MAXI J1807+132
• An apparent positive relation between spin and orbital angular momentum in X-ray binaries
• Hints of Dark Matter Spikes in Low-mass X-ray Binaries: a critical assessment
• Empirical correlation between masses of black holes and Wolf-Rayet stars derived from their mass distributions in spectroscopic binaries