The Structure of the Inner HH 34 Jet from Optical Integral Field Spectroscopy

Beck, Riera, Raga & Reipurth (AJ, submitted)

A. Riera (Universitat Politècnica de Catalunya)

T. Beck (Gemini Observatory)

A. C. Raga (UNAM)

B. Reipurth (University of Hawai)

High Spatial/Spectral resolution studies High Spatial/Spectral resolution studies of Herbig-Haro sourcesof Herbig-Haro sources

The Gemini Multi-Object Spectrograph Integral Field Unit (GMOS IFU) couples high spatial and spectral resolution over a small spatial field for simultaneous coverage of several important spectral features in HH sources.

GMOS IFU Spectroscopy at GMOS IFU Spectroscopy at GeminiGemini

- The IFU in GMOS is a lenset+fiber fed system with spatial extents of:

3.”5 x 5” (500 0.”2 fibers) in 1 slit mode7” x 5” (1000 0.”2 fibers) in 2 slit mode

- Spectral fibers are lined up along the slit, and the resulting spectra are stacked in the y dimension on the 6144 x 4608 GMOS detector.

- GMOS IFU is available with a range of gratings+filters for R ~1900 to 4300 spectroscopy.

The HH 34 The HH 34 complexcomplex

HST images from Reipurth et al. (2002)

Velocity and Density Structure ofVelocity and Density Structure of

HH 34HH 34 from GMOS IFU Spectrafrom GMOS IFU Spectra

GMOS IFU Spectroscopy of HH 34GMOS IFU Spectroscopy of HH 34

• Observations obtained in February, 2003.• Data obtained in two-slit mode with R831 grating

for ~15.5 km/s sampling.• Three IFU fields were observed:

– one position (2 pointings) on the collimated jet (knots E through J). Final cube ~13”x5”

– and one position on the exciting source. Final Cube=7”x5”

Velocity StructureVelocity Structure

• 3-D Isosurface contour plots:– [SII] = 2x10-17 erg/cm2/A– H = 4x10-17 erg/cm2/A

Velocity StructureVelocity Structure

• 3-D Isosurface contour plots:– [SII] = 2x10-17 erg/cm2/A– H = 4x10-17 erg/cm2/A

GMOS IFU Spectroscopy of HH 34 GMOS IFU Spectroscopy of HH 34 – Barycentric Velocity plots– Barycentric Velocity plots

vr // = 5 km s-1 (10)

vr ┴= 20 km s-1 (40)

GMOS IFU Spectroscopy of HH 34 – GMOS IFU Spectroscopy of HH 34 – Velocity dispersionVelocity dispersion

HH 34 Jet – HH 34 Jet – electron electron

density and density and excitation excitation

mapsmaps

[S II] ratio map shows striped or banded structures: higher ne are found in the leading edges of the bs, and minima in the trailing sides.

GMOS IFU Spectroscopy of HH 34 – GMOS IFU Spectroscopy of HH 34 – Sulphur line ratios/knot positionsSulphur line ratios/knot positions

GMOS IFU Spectroscopy of the HH 34 GMOS IFU Spectroscopy of the HH 34 Jet – electron density channel mapsJet – electron density channel maps

• Sulphur shows significant “striped” structure, with high density regions corresponding to positions of bow-shocks

• line ratio = 1.4, low density limit (ne=<100/cm3), 0.5 high density limit (ne=>2000/cm3)

What We’ve learned from GMOS IFU What We’ve learned from GMOS IFU Spectroscopy…Spectroscopy…

More complex velocity and electron density structure is seen than has ever been detected with longslit spectroscopy or narrow band imaging.

Velocity and velocity dispersion peaks and troughs exist along the axis of the jet.

[SII] line ratios show that high electron density regions are associated with the down-flow side of each emission knot in the jet.