SDSS
WSRT (Josza et al.)
WHT spectrum (Jarvis et al.)
WIYN (Keel/Manning)
Westerbork (Josza et al, ASTRON)
Orange= neutral hydrogen emission (8x109 solar masses)
Contours = 20 cm continuum core/outflow
Star-forming regions
Edge brightening –
interaction with an
outflow?
The Hole
No radial or ionization
structure around hole
Star formation in Hanny’s Voorwerp
Low-ionization Ha
[O III]/Ha
Far-red continuum
Hubble Legacy Archive V+I (S. Baum et al.)
Contours: Ha from SARA 0.6m
Pure jet-induced star formation in Minkowski’s Object
Near NGC 541, z=0.018
4x SFR, 6x radio power of IC 2497/ Voorwerp
Dust patches near line to nucleus
IR peak closely matches VLBI core
Warped dusty arms
Expanding loop – crosscut
in STIS spectra at Ha
Ha
[O III]
Continuum (STIS acquisition)
Merger (probably
not involving with
the small, symmetric
spiral companion)
releases H I tail
Accretion fuels luminous AGN,
radiation ionizes part of H I tail
Change in accretion launches
expanding gas ring from nucleus.
Broad radio outflow launched as
well, eventually interacting with H I
tail to trigger star formatipn in
densest/closest parts
Dramatic drop in ionizing radiation,
nucleus becomes LINER, we see
ionization echo as Voorwerp
Transie
source
Westerbork (Josza et al, ASTRON)
Orange= neutral hydrogen emission
Contours = 20 cm continuum core/outflow
ESO 2.2m
SARA 0.6m
“Garland” in Centaurus A emission-line filaments along jet