The black hole candidate XTE J1752−223 towards and in quiescence: optical and simultaneous X-ray-radio observations

Abstract

We present optical, X‐ray and radio observations of the black hole transient (BHT) XTE J1752−223 towards and in quiescence. Optical photometry shows that the quiescent magnitude of XTE J1752−223 is fainter than 24.4 mag in the i′ band. A comparison with measurements of the source during its 2009–2010 outburst shows that the outburst amplitude is more than 8 mag in the i′ band. Known X‐ray properties of the source combined with the faintness of the quiescence optical counterpart and the large outburst optical amplitude point towards a short orbital‐period system (Porb≲ 6.8 h) with an M type (or later) mass donor, at a distance of 3.5 ≲d≲ 8 kpc. Simultaneous X‐ray and radio data were collected with Chandra and the Expanded Very Large Array (EVLA), allowing constraints to be placed on the quiescent X‐ray and radio flux of XTE J1752−223. Furthermore, using data covering the final stage of the outburst decay, we investigated the low‐luminosity end of the X‐ray–radio correlation for this source and compared it with other BHTs. We found that XTE J1752−223 adds to the number of outliers with respect to the ‘standard’ X‐ray–radio luminosity relation. Furthermore, XTE J1752−223 is the second source, after the BHT H1743−322, that shows a transition from the region of the outliers towards the ‘standard’ correlation at low luminosity. Finally, we report on a faint, variable X‐ray source we discovered with Chandra at an angular distance of ∼2.9 arcsec to XTE J1752−223 and at a position angle consistent with that of the radio jets previously observed from the BHT. We discuss the possibility that we detected X‐ray emission associated with a jet from XTE J1752−223.

Constraints on relativistic jets in quiescent black hole X-ray binaries from broad-band spectral modelling

“…For example, for J1118, the slope of the NIR-optical spectrum in the hard state has been observed to range from very steep (αν ∼ −1.4; Russell et al 2013) to values more typical of optically thin synchrotron radiation (αν ∼ −0.8; Hynes et al 2006;Russell et al 2013) at different epochs, which could be reflecting different levels of particle acceleration. In addition to the above arguments that BHXBs eventually reach a quiescent baseline, the idea for less variety in quiescence might also be supported by multiwavelength observations that track transient BHXBs through the radio/X-ray luminosity plane as they fade into quiescence following an outburst (e.g., Jonker et al 2010Jonker et al , 2012Ratti et al 2012), To test the above idea further, it would be helpful to have a prediction on the expected slope of radio/X-ray luminosity correlations if X-rays are dominated by SSC (from a thermal electron distribution), and also more simultaneous radio and X-ray constraints on highly quiescent black holes (to learn if all quiescent black holes have similar radio to X-ray flux ratios).…”

The radio/X-ray domain of black hole X-ray binaries at the lowest radio luminosities

“…New observations of known sources, along with newly discovered ones, have resulted in an increasingly large number of outliers lying well outside the scatter about the previously established best-fitting relation (Corbel et al 2004;Brocksopp et al 2005;Cadolle Bel et al 2007;Rodriguez et al 2007;Gallo et al 2007;Xue & Cui 2007;Jonker et al 2010;Coriat et al 2011;Soleri & Fender 2011;Soria et al 2011;Ratti et al 2012;Brocksopp et al 2013). In Gallo, Miller & Fender (2012, GMF12 hereafter), making use of state of the art data clustering algorithms, we showed that a dual cluster model, with independent linear fits (in log space), was a significant improvement over fitting all points from 18 BHBs as a single cluster.…”

Revisit the Fundamental Plane of black hole activity from sub-Eddington to quiescent state

“…Some LH-state XRBs that stay in 'outliers' track or have only few simultaneous observations are neglected. Five quiescent XRBs with simultaneous or quasi-simultaneous radio and X-ray observations were selected from literatures, which are XTE J1752-223 (Ratti et al 2012), H1743-322 (Coriat et al 2011), XTE J1118+480 (Gallo et al 2014), A06200-00 and V404 Cyg ). The radio luminosity at 5 GHz and X-ray luminosity in 2-10 keV band were adopted in our work, where the radio emission observed in different waveband is extrapolated to a The reference for distance, X-ray luminosity, radio luminosity and BH mass respectively, which are shown as follows : 1) Note: a) The 0.3-7keV X-ray flux is converted to 2-10keV flux by assuming a power law spectrum with Γ = 2 (see also, Miller et al (2012)) b) The 5 GHz radio core emission of NGC 3884 is observed by MERLIN, operated by Jodrell Bank Observatory with resolution of ∼ 0.5 ′′ ;…”

“…The quasi-simultaneous radio and Xray fluxes in LH state of XRBs roughly follow a universal nonlinear correlation (FR ∝ F b X , b ∼ 0.5 − 0.7, Hannikainen et al 1998;Corbel et al 2003;Gallo et al 2003;Corbel et al 2013). Recently, more and more XRBs deviate from the universal correlations (e.g., Xue & Cui 2007;Cadolle Bel et al 2007;Soleri et al 2010;Jonker et al 2010;Coriat et al 2011;Ratti et al 2012) and form a different 'outliers' track with a much steeper radio-X-ray correlation (b ∼ 1.4 as initially found in H1743−322, Coriat et al 2011). Cao et al (2014) found that the X-ray spectral evolutions are different for the data points in the universal and 'outliers' tracks, which support that these two tracks may be regulated by radiatively inefficient and radiatively efficient accretion discs respectively (see also Coriat et al 2011;Huang et al 2014;Qiao & Liu 2015).…”