Another thread in the tapestry of stellar feedback: X-ray binaries

Abstract

We consider X-ray binaries (XBs) as potential sources of stellar feedback. XBs observationally appear able to deposit a high fraction of their power output into their local interstellar medium, which may make them a non-negligible source of energy input. The formation rate of the most luminous XBs rises with decreasing metallicity, which should increase their significance during galaxy formation in the early universe. We also argue that stochastic effects are important to XB feedback (XBF) and may dominate the systematic changes due to metallicity in many cases. Large stochastic variation in the magnitude of XBF at low absolute star formation rates provides a natural reason for diversity in the evolution of dwarf galaxies which were initially almost identical, with several percent of such halos experiencing energy input from XBs roughly two orders of magnitude above the most likely value. These probability distributions suggest that the effect of XBF is most commonly significant for total stellar masses between ~10^7 and 10^8 Msun, which might resolve a current problem with modelling populations of such galaxies. We explain how XBs might inject energy before luminous supernovae (SNe) contribute significantly to feedback and how XBs can assist in keeping gas hot long after the last core-collapse SN has exploded. [...] XBF could be especially important to some dwarf galaxies, potentially heating gas without expelling it; the properties of XBF also match those previously derived as allowing episodic star formation. We also argue that the efficiency of SN feedback (SNF) might be reduced when XBF has had the opportunity to act first. In addition, we note that the effect of SNF is unlikely to be scale-free; galaxies smaller than ~100 pc might well experience less effective SNF. (Slightly abbreviated to fit arXiv size limit.)Comment: Very belatedly updated to include a note added in proof and additional reference. The definitive version is at: mnras.oxfordjournals.org/content/423/2/164

Feedback From High-Mass X-Ray Binaries on the High-Redshift Intergalactic Medium: Model Spectra

“…There are compelling astrophysical reasons to expect that HMXBs, which are observed to be a natural by-product of massive-star formation (e.g., Mineo et al 2012a;Dijkstra et al 2012), could be an important source of feedback in galaxy formation over cosmic time (e.g., Justham & Schawinski 2012). Because the cross section for photons to be absorbed by neutral hydrogen decreases strongly with energy as E −3 γ , X-rays from HMXBs can effectively diffuse through the IGM and deposit their energy at relatively large distances from the stellar population, in an act of non-local feedback (a similar effect is expected for mini-quasars; see, for example, Zaroubi & Silk 2005).…”

“…Linden et al 2010;Justham & Schawinski 2012). There is also observational evidence that the black hole mass is likely to be larger in lower metallicity systems (cf.…”

Resolving the X-ray emission from the Lyman-continuum emitting galaxy Tol 1247-232

“…Hence, the diffuse emission must be powered by other means. Justham & Schawinski (2012) suggest that X-ray binaries may dominate the energy input to the ISM for starburst ages less than 6 Myr and that the relative importance of X-ray binaries versus supernovae will be greatest for near solar metallicity galaxies with starburst masses near 10 8 M . Hence, Tol 1247-232, with a starburst mass of 1.3 × 10 8 M (Rosa González et al 2007), may be a good candidate for a galaxy in which feedback and heating of the ISM is dominated by X-ray binaries.…”

Shell-shocked: the interstellar medium near Cygnus X-1

“…Conducting measurements of stellar-mass BH jets enables us to test the scale-invariance of BH jets (Heinz & Sunyaev 2003;Merloni et al 2003;Falcke et al 2004) and understand the feedback potential of XRBs (Heinz & Grimm 2005;Fender et al 2005;Justham & Schawinski 2012). This is particularly relevant for Cygnus X-1, where the accretion flow produces steady, relativistic jets in the low/hard state (Pooley et al 1999;Wilms et al 2006).…”