Rapid variability of the arcsec-scale X-ray jets of SS 433

Abstract

We present the X-ray images of all the available Chandra observations of the galactic jet source SS 433. We have studied the morphology of the X-ray images and inspected the evolution of the arcsec X-ray jets, recently found to be manifestations of in situ reheating of the relativistic gas downstream in the jets. The Chandra images reveal that the arcsec X-ray jets are not steady long term structures; the structure varies, indicating that the reheating processes have no preference for a particular precession phase or distance from the binary core. Three observations made within about five days in May 2001, and a 60 ks observation made in July 2003 show that the variability of the jets can be very rapid, from timescales of days to (possibly) hours. The three May 2001 images show two resolved knots in the east jet getting brighter one after the other, suggesting that a common phenomenon might be at the origin of the sequential reheatings of the knots. We discuss possible scenarios and propose a model to interpret these brightenings in terms of a propagating shock wave, revealing a second, faster outflow in the jet.Comment: accepted for publication in MNRA

Non-ballistic superluminal motion in the plane of the sky - II.

“…The deviation in the precession phase of knots A and B corresponds to a time discrepancy of 38 d. It takes 36 d for a signal to propagate from knot A to knot B. Hence, knot B is brightened up 2 d later than knot A, which satisfies the observation (Migliari et al 2005) in a much simpler way.…”

“…The middle panel is a schematic diagram of the orientation of the east jet of SS 433, which interprets the observations of knots A and B in the context of the slowly moving clouds energized erratically by a more powerful, faster, unseen flow. The top and middle panels are taken from Migliari et al (2005). The bottom panel is a schematic diagram explaining the observations of knots A and B using the non‐ballistic model.…”

“…The model of the two knots moving in certain positions, and then brightened up by two shocks sequentially (Migliari et al 2005), is shown in the middle panel of Fig. 5.…”

Identification of X-ray lines in the spectrum of the arcsec-scale precessing jets of SS 433

“…Based on the constraints on the origin of the observed lines obtained here, namely the requirements of high temperature of the emitting plasma and relatively long duration of the brightening episode ∆τ ∼ 0.6, and taking into account the observed rapid (down to scales of several hours, Migliari et al 2005) stochastic variability of the X-ray emission, we suggest that dissipation of the jets' kinetic energy via collisions of their discrete dense blobs due to their deceleration by the medium of the jets' cocoons, provides a natural explanation of the observed characteristics of the arcsec-scale X-ray emission.…”

Using SKA to observe relativistic jets from X-ray binary systems

“…This is probably due to the small angle of the Cir X-1 jet to the line of sight and suggests that at least all six neutron star 'Z' sources (of which Sco X-1 is the archetype) are producing such 'ultrarelativistic' flows. SS 433 may also be producing such a flow, resulting in transient energisation of the well-known knots which move at ∼ 0.26c (Migliari et al 2004). …”