Global Jet Watch

Abstract:

[ABRIDGED] The distance to the relativistic jet source SS433 and the related supernova remnant W50 is re-examined using new observations of HI in absorption from the VLA, HI in emission from the GBT, and 12CO emission from the FCRAO. The new measurements show HI in absorption against SS433 to a velocity of 75 km/s but not to the velocity of the tangent point, which bounds the kinematic distance at 5.5 < d_k < 6.5 kpc. This is entirely consistent with a 5.5 +/- 0.2 kpc distance determined from light travel-time arguments (Blundell & Bowler 2004). The HI emission map shows evidence of interaction of the lobes of W50 with the interstellar medium near the adopted systemic velocity of V_LSR = 75 km/s. The western lobe sits in a cavity in the HI emission near the Galactic plane, while the eastern lobe terminates at an expanding HI shell. The expanding shell has a radius of 40 pc, contains 8 +/- 3 x 10^3 M_sun of HI and has a measured kinetic energy of 3 +/- 1.5 x 10^{49} ergs. There may also be a static HI ring or shell around the main part of W50 itself at an LSR velocity of 75 km/s, with a radius of 70 pc and a mass in HI of 3.5 - 10 x 10^4 M_sun. We do not find convincing evidence for the interaction of the system with any molecular cloud or with HI at other velocities. The HI emission data suggest that SS433 lies in an interstellar environment substantially denser than average for its distance from the Galactic plane. This Population I system, now about 200 pc below the Galactic plane, most likely originated as a runaway O-star binary ejected from a young cluster in the plane. New astrometric data on SS433 show that the system now has a peculiar velocity of a few tens of km/s in the direction of the Galactic plane. From this peculiar velocity and the symmetry of the W50 remnant we derive a time since the SN of < 10^5 yr.

Abstract:

We analyzed the feedback of AGN jets on cooling flow clusters using three-dimensional AMR hydrodynamic simulations. We studied the interaction of the jet with the intracluster medium and creation of low X-ray emission cavities (Bubbles) in cluster plasma. The distribution of energy input by the jet into the system was quantified in its different forms, i.e. internal, kinetic and potential. We find that the energy associated with the bubbles, (pV + gamma pV/(gamma-1)), accounts for less than 10 percent of the jet energy.

Abstract:

We report the discovery of an X-ray counterpart to the southern radio hotspot of the largest-known radio quasar 4C 74.26 (whose redshift is z=0.104). Both XMM-Newton and Chandra images reveal the same significant (10arcsec, i.e. 19kpc) offset between the X-ray hotspot and the radio hotspot imaged with MERLIN. The peak of the X-ray emission may be due to synchrotron or inverse-Compton emission. If synchrotron emission, the hotspot represents the site of particle acceleration and the offset arises from either the jet exhibiting Scheuer's `dentist's drill' effect or a fast spine having less momentum than the sheath surrounding it, which creates the radio hotspot. If the emission arises from the inverse-Compton process, it must be inverse-Compton scattering of the CMB in a decelerating relativistic flow, implying that the jet is relativistic (Gamma >= 2) out to a distance of at least 800kpc. Our analysis, including optical data from the Liverpool Telescope, rules out a background AGN for the X-ray emission and confirms its nature as a hotspot, making it the most X-ray luminous hotspot yet detected.