Radio Emission from the Be/Black Hole Binary MWC 656

Abstract

Context. MWC 656 is the recently discovered first binary system case composed of a Be-type star and an accreting black hole. Its low X-ray luminosity indicates that the system is in a quiescent X-ray state. Aims. The aim of our investigation is to establish if the MWC 656 system has detectable radio emission and if the radio characteristics are consistent with those of quiescent black hole systems. Methods. We used three archived VLA data sets, one hour each, at 3 GHz and seven new VLA observations, two hours each, at 10 GHz to produce very high sensitivity images, down to $\sim$1$\mu$Jy. Results. We detected the source twice in the new observations: in the first VLA run, at periastron passage, with a flux density of 14.2$\pm$2.9 $\mu$Jy and by combining all together the other six VLA runs, with a flux density of $3.7\pm 1.4$ $\mu$Jy. The resulting combined map of the archived observations has the sensitivity of $1\sigma =6.6\mu Jy$ but no radio emission is there detected. Conclusions. The radio and X-ray luminosities agree with the behaviour of accreting binary black holes in the hard and quiescent state. In particular, MWC 656 in the $L_X$, $L_R$ plane occupies the same region as A0620$-$00 and XTE J1118+480, the faintest known black holes up to now.

4 pages, 3 figures, 1 table, accepted in the Astronomy & Astrophysics letters. This new version contains language editor corrections and periastron phase updated

References in corpus (4)

• Measuring the kinetic power of AGN in the radio mode
• A radio-emitting outflow in the quiescent state of A0620-00: implications for modelling low-luminosity black hole binaries
• The radio/X-ray domain of black hole X-ray binaries at the lowest radio luminosities
• Discovery of X-ray emission from the first Be/black hole system

Cited by in corpus (19)

• WATCHDOG: A Comprehensive All-Sky Database of Galactic Black Hole X-ray Binaries
• The first low-mass black hole X-ray binary identified in quiescence outside of a globular cluster
• The First Simultaneous X-Ray/Radio Detection of the First Be/BH System MWC 656
• A Clean Sightline to Quiescence: Multiwavelength Observations of the High Galactic Latitude Black Hole X-ray Binary Swift J1357.2-0933
• MWC 656 is unlikely to contain a black hole
• Radio Variability from a Quiescent Stellar Mass Black Hole Jet
• Observations of the Disk/Jet Coupling of MAXI J1820+070 During its Descent to Quiescence
• Optical spectroscopy of Be/gamma-ray binaries
• Optical Precursors to Black Hole X-ray Binary Outbursts: An evolving synchrotron jet spectrum in Swift J1357.2-0933
• Polarized synchrotron emission in quiescent black hole X-ray transients
• GS 2000+25: The Least Luminous Black Hole X-ray Binary
• Evidence for periodic accretion-ejection in LSI+61303
• The gamma-ray source AGL J2241+4454 as the possible counterpart of MWC 656
• ALMA observations of A0620-00: fresh clues on the nature of quiescent black hole X-ray binary jets
• Toward a Larger Sample of Radio Jets from Quiescent Black Hole X-ray Binaries
• Polarimetry of binary systems: polars, magnetic CVs, XRBs
• Optical spectroscopy of the Be/black hole binary MWC656 -- interaction of a black hole with a circumstellar disc
• The flickering radio jet from the quiescent black hole X-ray binary A0620-00
• Ultraviolet spectroscopy reveals a hot and luminous companion to the Be star+black hole candidate MWC 656