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TAURUS Tunable Filter and astronomical applications

TAURUS Tunable Filter and astronomical applications. Sonia Cianci (USyd / AAO). Overview:. TAURUS Tunable Filter What it is, and how it works Observing modes time series imaging frequency switching straddle shuffling nod and shuffle Astronomical applications. TAURUS operating modes.

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TAURUS Tunable Filter and astronomical applications

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  1. TAURUS Tunable Filter and astronomical applications Sonia Cianci (USyd / AAO)

  2. Overview: • TAURUS Tunable Filter • What it is, and how it works • Observing modes • time series imaging • frequency switching • straddle shuffling • nod and shuffle • Astronomical applications

  3. TAURUS operating modes • Tunable imaging - TTF • 3D line mapping • Multi-slit spectroscopy • Polarimetry • All operating modes support: • Time series observations • charge shuffling • nod and shuffle

  4. TTF: What is it? • Pair of Fabry-Perot interferometers • Blue arm: 3700 - 6500 Å • Red arm: 6500 - 9600 Å • Bandpass: 6 - 60 Å • 10 arcmin field at f/8 on AAT (0.37’’ per pixel) • Each arm has two highly polished glass plates • High performance coatings • Piezoelectric stacks to control plate separation

  5. FPs as tunable filters m  = 2  l cos  R = m N dR dm dl ---- = ---- = --- R m l 4 - 40 100 - 1000 1.5 - 15 m

  6. TTF resolving power

  7. Periodic TTF transmission profile 7.0 m 12.0 m

  8. TTF order sorting filters

  9. TTF blocking filters designed to fit within windows free of OH night-sky emission

  10. Orion (H, [NII]6583, [SII]6717)

  11. MR 2251-178: the Largest Known Quasar Nebula (Shopbell, Veilleux, & Bland-Hawthorn 1999) • One of the few radio-quiet quasars with an extended gaseous nebula • Spiral complex extends more or less symmetrically over ~ 200 kpc • M(nebula) < 6 x 1010 Msun (ionized) • Photoionized by the quasar • Smooth large-scale rotation, in opposite sense to the inner region of the galaxy • Morphology and large-scale rotation seem to rule out origin from cooling flow, past merger event, or interaction with nearby galaxy G1 • Favor a model in which the extended ionized nebula resides within a large complex of HI gas centered on the quasar H jet axis maximum vel. gradient Z = 0.0638 Sensitivity: ~ few 10-18 erg s-1 cm-2 arcsec-2 (m ~ 1 cm-6 pc ~ 0.5 R) – 10x fainter than typical narrow-band images…

  12. D.H. Jones thesis

  13. B1 B2 B1 B2 B1 B2 9’ TaurusField B1 B2 B1 Slot Mask Time Series Tunable Filter • TTF can be used in a time series mode, where charge shuffling is used to acquire a series of interleaved bands with very small dead time (~1s). • February & August 1998 observed in trying AAT conditions (ie. rain, cloud & 4” seeing), but got several 2.5 hour sequences on LP 944-20 • M9.5 type brown dwarf, age=500Myr, mass=0.06M • 3 x 2.5 hour chunks which showed significant evidence for variability. 2Kx4KCCD

  14. Charge is shuffled into “storage” area Charge is shuffled back down And then the charge shuffles again, and collects more photons in the second band TTF switches back to the first band and collects more photons TTF switches to second band and takes a second image TTF takes data in first bandpass And so on ….. And so on ….. And so on ….. Instrument illuminates centre of 15m pixel 2Kx4K CCD

  15. Can also image in closely spaced emission / absorption lines...

  16. TTF charge shuffle imaging NGC2437 (planetary nebula) Ratio maps are possible in non-photometric conditions...

  17. NGC 2437 (H, [NII], [SII])

  18. Straddle shuffling Bland-Hawthorn & Jones, 1998

  19. Star formation in bright ellipticals: Galaxy is source of noise, not signal Straddle shuffling draws out faint emission Ferguson et al. 2001

  20. `Nod and shuffle’ KGB & JBH 2001

  21. “Standard” Spectrscopy with interpolation • Observations of brown dwarf D1228 • 1800s with nodding along slit every 30s. “Standard” technique is limited by the crappy slit, flat fielding, etc. “Nod & Shuffle” produces Poisson noise! Nod and shuffle with simple subtraction KGB & JBH 2001

  22. 500 pc 11 kpc H + [N II] HST M82 Warm ionised gas from superwinds is sometimes seen out to ~ 10 - 15 kpc from the galaxy nucleus (Shopbell & Bland-Hawthorn 1998; Devine & Bally 1999; Shopbell et al. 2001)

  23. Concluding remarks • TTF is a very versatile instrument • Different observing modes allow for wide variety of applications, e.g.: • faint emission • time variability • resolution of closely spaced emission/absorption lines • differential imaging (even in bad conditions!), etc. • Future tunable instruments being developed by AAO: • OSIRIS - for GranTeCan 10m • DAZLE - for VLT 8m

  24. References: Bland-Hawthorn, J. (2000) ASP Conference Series, 195, 34 Bland-Hawthorn, J. & Jones, D.H. (1998) SPIE, 3355, 855 Devine, D. & Bally, J. (1999) ApJ, 510, 197 Ferguson, A., van der Hulst, T. & van Gorkom, J. (2001) AAO Newsletter, No. 96 (February) Glazebrook, K. & Bland-Hawthorn, J. (2001) PASP, 113, 197 Shopbell, P.L. & Bland-Hawthorn, J. (1998) ApJ, 493, 129 Shopbell, P.L., Veilleux, S. & Bland-Hawthorn, J. (1999) ApJ, 524, L83 TTF Web page: http://www.aao.gov.au/ttf/

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