SIMBAD references

The large spiral galaxy NGC 4258 (M106) harbors the nearest extragalactic astrophysical jet. While low-resolution radio and X-ray observations indicate that the jet propagates outside the galaxy disk, high-resolution optical and CO millimeter observations point instead to a propagation within the gaseous disk of the galaxy. We have used a simple analytical model to explore a scenario where the jet propagates at an angle of ∼2° with respect to the plane of the galaxy in the inner disk and is forced out of the galaxy plane at a radius of ∼5 kpc. This scenario brings together the in-the-disk and out-of-the-disk views into a hybrid model which accounts for most of the observed properties of the jet. We show that (1) the component normal to the disk plane of the forces acting on the jet, dominated by ram pressure, has an amplitude sufficient to propel the jet out of the main disk at galactocentric distances of about 4-5 kpc; (2) the apparent deflections of the jet are probably caused by forces acting within the plane of the disk for the first few kiloparsecs, by the projection effect of the curved trajectory exiting the disk, and by chimney-type structures popping out of the disk at r>4 kpc. We suggest that the rich outer filamentary structures of the jet are due to breakout into the low-pressure halo gas.