JEUDI 15 mai 2003, à 14h, 77 avenue Denfert Rochereau
77 avenue Denfert Rochereau, Paris 14
Salle de l'Atelier, Observatoire de Paris
Gaseous environment near the active nucleus of Mrk~1 - Kinematics
and composition
Amitesh Omar
Raman Research Institute, Bangalore
Résumé :
Abstract: We present Giant Meterwave Radio Telescope (GMRT) observations
of the HI 21 cm line and Very Large Array (VLA) observations of the OH 18
cm line from the Seyfert 2 galaxy Mrk 1. Based on HI emission morphology,
we speculate that the nuclear activities of Mrk 1 are triggered by tidal
interactions with a nearby companion. We have detected two-component HI 21
cm line and the OH 18 cm line in absorption toward the nucleus of Mrk 1 at
blueshifted velocities with respect to its systemic velocity indicating an
outflow of atomic and molecular gas. The higher velocity components of the
HI and OH (1667 MHz) absorption lines are blueshifted from the O[III]5007,
O[I]6300, and the systemic velocity by ~ 100 km s$^{-1}$, but are consistent
with the O[II]3727 velocity. We explain these velocity discrepancies as
due to shock ionization of a region which is pushed forward due to shocks
in front of the radio nucleus thereby giving a blueshift to HI, OH,
and O[II] velocities. The optical depth ratios tau{HI}/tau{OH1667} of both
the components of the HI and OH absorption are ~3, indicating their origin
in dense molecular clouds.
