Integral Field Spectroscopy of Faint Haloes around Planetary Nebulae

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Integral Field Spectroscopy ofFaint Haloes
around Planetary Nebulae
Probing the mass-loss history at the tip of the
AGB
D. Schönberner M. Steffen M. Roth A. Monreal A.
Kelz
NGC 6720
(Spitzer Space Telescope)
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Outline

• Introduction PN haloes as fossil records of
  AGB mass loss
• Method Plasma diagnostics with Integral
  Field Spectroscopy
• PN halo observations with PMAS Observing
  statistics Preliminary results NGC 3587
  (PMAS) NGC 6720 (PMAS) NGC 3242
  (VIMOS)
• Conclusions outlook

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Mass loss at the tip of the AGB

• Strong, dust-driven stellar winds
• Enriched by freshly synthesized elements
  dredged-up from interior
• Important contribution to the recycling of
  matter in galaxies
• Short lifetime of high mass loss phases
  prevents direct detection
• Theory of mass loss on the AGB and beyond
  is highly uncertain
• ?Observational constraints are badly needed

2000 y
Structure of AGB star
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Mass loss at the tip of the AGB

• Strong, dust-driven stellar winds
• Enriched by freshly synthesized elements
  dredged-up from interior
• Important contribution to the recycling of
  matter in galaxies
• Short lifetime of high mass loss phases
  prevents direct detection
• Time-dependence of mass loss at end of AGB
  is largely unknown
• ?Observational constraints are badly needed

2000 y
Structure of AGB star
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Are Planetary Nebulae fossil records of the AGB
mass loss history ?
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A typical double shell PN
NGC6826, observed with HST
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IFU
NGC6826, observed with PMAS AG camera
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Method

• Measurement of plasma diagnostic emission lines
• Density diagnostics OII 3729 / OII
  3727 or SII 6718 / SII 6733 a maps of
  absolute electron densities
• Temperature diagnostics (OIII 4960
  OIII 5007 ) / OIII 4363 N II a maps
  of electron temperatures

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Integral field spectroscopy of PN
haloes Radiation-hydrodynamics simulations

• Goals
• Radial density structure a Final mass loss
  episode
• Temperature, density a Type and age of
  halo
• Chemical abundances a Nucleosynthesis
  dredge-up
• Physics of mysterious ring structures within
  haloes
• Detection of new haloes not found by direct
  imaging

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Advantages of Integral Field Spectroscopy

• Allows spectroscopic investigation of
  extremely low surface brightness targets
• High sensitivity due to superbinning capability
• Spatial information Slit versus IFU
• PMAS nod shuffle mode for accurate sky
  background subtraction
• PMAS large ? coverage, good UV sensitivity

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Statistics of PN halo observations with PMAS
run23
10-18 Feb 2004
19-23 Feb 2004
18-22 Aug 2004
23-28 Aug 2004
useful night
run36
14/15 Mar 2005
poor observing conditions
Total 8 / 23
clouds/humidity, no observations
telescope problems
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Preliminary results

• PMAS NGC 3578 (Owl nebula)
• PMAS NGC 6720 (Ring nebula)
• VIMOS NGC 3242 (Jupiters Ghost)
• (NGC 6826)

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Conclusions

• Integral Field Spectroscopy of faint haloes
  around Planetary Nebulae is feasible
• Line fluxes as low as 5 10 18
  erg/cm2/s/arcsec2 can be detected using the
  nod shuffle technique even under less than
  ideal conditions (grey time)
• Some interesting new results have already been
  obtained temperature gradients within AGB
  haloes (NGC 3242, NGC 3578)
• More PMAS observing time is needed to achieve
  goals (VIMOS less useful)

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Interior structure of an AGB star
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NGC 6543 (Cats eye) as seen by HST
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Density diagnostics OII
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Density diagnostics SII
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Temperature diagnostics OIII
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Temperature diagnostics NII
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Beam Switching Nod-Shuffle Spectroscopy
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Cuillandre et al. 1994, AA 281, 603
Va et Vient
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Cuillandre et al. 1994, AA 281, 603
Va et Vient
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Cuillandre et al. 1994, AA 281, 603
Va et Vient
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Cuillandre et al. 1994, AA 281, 603
Va et Vient
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NGC 3587 (O III, Palomar 5m)
Teff 105 kKL 70 L?
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NGC 3587, PMAS guider image
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NGC 3587 radial surface brightness profile (H?
and O III)
PMAS data
edge of halo
Hydro model
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Temperature gradient across PN halo model results
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Temperature gradient across PN halo NGC 3587
?Spurious abundance gradient ?
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Corresponding PN equilibrium model
Flat T-profile
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Teff 130 kKL 500 L?
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NGC 6720 PMAS guider image
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NGC 6720 PMAS guider image
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NGC 6720 PMAS guider image
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NGC 6720 PMAS guider image
O II map
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Conventional sky subtraction
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Nod shuffle sky subtraction
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Conventional sky subtraction
Hg sky line
OIII 4363
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Nod shuffle sky subtraction
Hg sky line
OIII 4363
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Radial intensity profile in H?
Radial density profile from Abel inversion ?
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Radial emissivity profile in H?
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NGC 3242 VIMOS FOV 54? x 54?
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NGC 3242 Ring system
Corradi et al. 2004
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NGC 3242 Ring system
Radial temperature increasetowards outer halo!
20300 K
15700 K
VIMOS data (Monreal-Ibero et al. 2005)
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First Commissioning Results August 2003
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Other Applications
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Dressler 1984, ApJ 286, 97
Ca II 8498
Ca II 8542
Ca II 8662
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Nod-Shuffle Spectroscopy of faint Haloes of
Planetary Nebulae

• D. Schönberner
• M. Steffen
• C. Sandin
• M. Roth
• T. Becker
• A. Kelz
• R. Corradi (ING)
• K. Exter (IAC)

NGC7293 credit R. Corradi
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http//www.aip.de/Euro3D/
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A typical double shell PN
NGC 6826 (Ha)
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NGC2022, O III
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Schönberner Steffen 2002
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Wachter et al. 2002
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