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AO-Assisted Spectroscopy of the Emission-Line Region at the Base of the SVS13/HH7-11 Jet. Chris Davis (Joint Astronomy Centre). 1. Do all those stars really drive outflows??. 2. How do they do it, exactly…?. How can we observationally test wind models…?.
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AO-Assisted Spectroscopy of the Emission-Line Region at the Base of the SVS13/HH7-11 Jet Chris Davis (Joint Astronomy Centre)
1. Do all those stars really drive outflows?? 2. How do they do it, exactly…?
How can we observationally test wind models…? • Observe as close to star as possible - before interaction with ambient medium • Use line-emission produced at the jet base as a diagnostic tool. • Longer wavelengths… younger sources. • High spatial resolution… at 150 pc, 1 arcsec = 150 AU. • Disk winds from few AU radii - we need milli-arcsecond resolution…! • Disentangle line from noisey continuum… • Cronographic imaging? • IFU observations (perfect continuum subtraction) • High-resolutionspectroscopy (slit along/perp to jet axis)
FP imaging of the Jet Base (H2) SVS13 line continuum
NACO on VLT4/Yepun • NAOS/CONICA: • 27mas pixels • 172 mas slit width • R~1000 • H-band: 1.50-1.73 mm • K-band: 2.05-2.35 mm • For the Infrared Wavefront • Sensor/AO Guide star: • K < 11-12th • Dichroics: • N20C80 - 20% to WFS, 80% to Conica • N90C10 - 90% to WFS, 10% to Conica
Profile plots... • FeII peak, offset: • 0.061(0.004)” = 18.3AU • BrG peak, offset: • 0.001(0.003)” = <1AU • CO peak, offset: • 0.004(0.003)” = <1AU • H2components, offsets: • 4.8(0.1)” = 1430(30) AU • 2.0(0.1)” = 600(30) AU • 1.19(0.02)” = 360(6) AU • 0.29(0.02)” = 90(6) AU As peaks move further out - they expand!?
Origin of the line emission... Gas cools as flows along jet Discrete knots ejected along flow axis …Additional Clues from Proper Motions? Compare CGS4 data from Sept 1999 with NACO data from January 2005. 5.4 years -- 100 km/s ------ Knot would move 113AU or 0.38”
Proper motions…. SVS13 jet CGS4: HVC peak at 0.35”(0.1)” LVC peak at 0.20”(0.1)” NACO: bright peak at 0.29”(0.03)” fainter peak at 1.2” (fainter peak at 2.0”) HH 7 No proper motions -- heating at jet base? or Multiple/expanding knots -- bows?
Some final thoughts...…. A useful means of probing spatial info. at the base of YSO jets, particularly younger systems… Follow-up proper motion studies; don’t wait too long! • Wish list: • High-spectral-resolution spectrometer with IR AO capabilities…! (Tae-Soo Pyo, Hiro Takami…) • An IFU with IR AO, for excitation studies (more spatial info.; better sky subtraction)? • Mid-IR AO capability??