Fabry-Perot Imaging of the Oxygen-Rich Supernova Remnant G292.0+1.8:
A Benchmark for Exploring Ejecta Kinematics in Core Collapse SNe
Parviz Ghavamian
The object G292.0+1.8 is one of three core collapse supernova remnants in the
Galaxy whose ejecta can be observed at optical wavelengths (commonly known
as 'oxygen-rich SNRs, or OSNRs'). The ejecta are highly clumped and exhibit
optical spectra devoid of hydrogen, helium and nitrogen emission and dominated
by forbidden lines of oxygen, neon and sulfur. Recent Chandra X-ray imagery
of G292.0+1.8 has revealed a spectacular array of ejecta filaments, bubbles and
clumps, contained in an ellipsoidal shell and bisected E-W by a barlike
structure of cosmic composition. The bar is likely a ring of relic circumstellar
material comparable to the ring in SN 1987A but viewed edge-on. Within the past
two years both Chandra and radio data have shown that G292.0+1.8 harbors a 135
millisecond pulsar (J1124-5916) and an active pulsar wind nebula. I will show that
we can map the 3D kinematics of the ejecta in this complex OSNR using [O III]
and H-alpha imaging from the Rutgers Fabry-Perot spectrometer. Our results show
that the optical ejecta in G292.0+1.8 are kinematically segregated into
three components: (1) stationary circumstellar wind material seen in Halpha,
[O III] and X-rays, (2) mostly blueshifted, fast-moving knots (FMKs similar to
Cas A) traveling at at 1700 km/s and distributed in ring-like patterns over an
expanding shell. The kinematic age is 3000-3400 years, similar to the pulsar
spindown age; and (3) a large spur of mostly redshifted ejecta expanding at
1700 km/s and distorted by what are likely to be Rayleigh-Taylor instabilities.
Our analysis indicates that unlike Cas A, the massive, > 20 M_sun progenitor
of G292.0+1.8 likely exploded into a low density circumstellar medium.