Discovery of a new subparsec counterjet in NGC 1275: the inclination
  angle and the environment
  We report the detection of a new feature at the centre of NGC 1275 in the
Perseus cluster, hosting the radio source 3C 84. This feature emerges ~ 2 mas
(~ 0.8 pc) north of the central core in recent 15 and 43 GHz VLBA images, and
seems to be the counterjet to a known radio jet expanding to the south of the
core. Apparently, the two jets were born through an outburst around 2005. From
the ratio of the apparent lengths of the two jets from the core, we found that
the jet angle to the line of sight is \theta=65^\circ\pm 16^\circ, which is not
much different from the angle of the outer jets generated by an activity around
1959 and constrains theories on gamma-ray emission from jets. The new northern
jet has a strongly inverted spectrum in contrast with the southern jet. This
suggests that the central black hole is surrounded by a subparsec-scale
accretion disk with the density of >~ 10^5 cm^-3. The brightness of the
counterjet suggests that the disk is highly inhomogeneous. The ambient gas
density in the direction of the jet is ~ 8 cm^-3 if the current jet activity is
similar to the past average.
