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The Planetary Nebulae Luminosity Function for Galactic Bulge Planetary Nebulae

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to model the observations. Found since to work across all galaxies Ciardullo (03) ... for PNLF bright end in elliptical ( 10Gyr) galaxies? Possible explanations... – PowerPoint PPT presentation

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Title: The Planetary Nebulae Luminosity Function for Galactic Bulge Planetary Nebulae


1
The Planetary Nebulae Luminosity Function for
Galactic Bulge Planetary Nebulae
  • Anna Kovacevic
  • Quentin Parker, George Jacoby, Rob Sharp, Brent
    Miszalski

Legacies of the Macquarie/AAO/Strasbourg Ha
Planetary Nebula project Sydney, February 16-18th
2009
2
Main points
  • Background of Luminosity Function
  • Problems and solutions
  • Observations
  • Reductions and preliminary results
  • Excitation class
  • Further exploitation of this data

3
Background of the PNLF
  • Theoretical foundation first laid out by Jacoby
    (89)
  • Ciardullo et al. (89) fit the theoretical curve
    to 76 PNe in the dust-free regions in M31
  • Proposed
  • N(m) 8 e0.307M( 1 e3(M- M))
  • to model the observations
  • Found since to work across all galaxies Ciardullo
    (03)

Ciardullo et al. (1989)
?powerful extra-galactic distance indicator
4
Problems and solutions
  • Absolute magnitude of bright end invariant to
    population age
  • ? requires CSs to be gt0.6Msolar, which
    corresponds to a mass on the main-sequence of
    gt2Msolar. Stellar evolution dictates only live
    for 1Gyr
  • How can we account for PNLF bright end in
    elliptical (gt10Gyr) galaxies?
  • Possible explanations.
  • Ciardullo (05) ? massive central stars in old
    populations produced through binary evolution.
  • - BSs where 2 1M? stars merged on MS to form
    a 2Msolar star

5
What do the theorists think?
  • Marigo et. al (2004,2006) assume single-star
    post-AGB evolution and used nebular models
  • - constructed PNLFs for populations with
    different metallicities and star formation
    histories
  • - Found bright end made up of PNe with CS
    masses 0.7-0.75Msolar
  • ? Bright end absolute magnitude must be
    dependent on properties of underlying population
  • Schonberner (2007) use radiation-hydrodynamical
    models simulations produce OIII luminosity
    evolution of PNe
  • - Models suggest most PNe are optically thin
    with CS TEgt45000K,
  • ? cannot explain bright end
  • - Models with CS mass gt0.6Msolar dense,
    optically thick nebula do provide OIII
    luminosity required to populate bright end.

6
What can we do to improve our understanding
observationally
  • We have clear evidence that massive central stars
    in old elliptical galaxies do exist, so the
    question we need to answer now is how do they
    exist
  • To understand how the PNLF works we need a
    complete, volume-limited sample that is near
    enough that we are able to resolve their
    morphologies as well as able to attain high S/N
    spectra relatively easily.
  • This has been done for the Local 1kpc volume
    (Frew), the LMC(Reid) and the Galactic Bulge
    (this work).
  • ? Questions we can ask
  • Which parts of the LF do different population
    subsets (Type I, binary) occupy?
  • Is the robustness of the PNLF just due to one
    of these subsets?
  • Do PNe with a certain morphology/excitation
    class dominate certain parts of the PNLF?

7
Round 1 - Chile
b
l
  • 6 nights using MOSAIC-II camera on 4-m Blanco at
    CTIO
  • Large mirror to minimise exposure times on the
    faintest PNe
  • 36 x 36 camera
  • 0.27/pixel
  • Chose 10x10 region in the Bulge
  • Excellent instrument
  • Excellent site
  • gt Fields placement ensuring all PNe observed
    with a minimum amount of fields.
  • gt Ensuring maximum overlap to check
    flux-calibration between fields.
  • gt Targeted Southern Bulge as higher number of
    PNe per field

8
Chile cont
  • Outcomes
  • 6 nights of photometric sub-arcsecond seeing
    weather ?
  • Observed 78 out of the 175 fields
  • Observed 57 of PNe in 45 of fields
  • Therefore 43 of PNe to observe in remaining 55
    of fields.
  • With another 5 clear nights, we could achieve
    95 completeness for OIII observed PNe in the
    b lt 5 l lt 5 region

9
Round 2 - Chile
  • 5 nights using MOSAIC-II on 4-m Blanco at CTIO in
    late June 2009
  • Mop up remaining fields

10
Reductions
  • Using CASU pipeline/toolkit developed by for the
    INT WFI data with CTIO add-ons
  • First mosaics have been made

and starting to make measurements
11
Examples
12
Current PNLF for the Bulge
  • Compiled for 101 PNe 44 listed in Escudero de
    Costa (2001) and 57 listed in Escudero et al.
    (2004).
  • The 44 were taken from Kohoutek (1994) and
    Beaulieu et al. (1999)

Bl3-13
M2-26
Al2-0
M4-7
M3-19
H1-46
KFL2
M2-20
Bulge PNLF constructed by Maciel, priv. comm.
13
Excitation class
low excitation object ? high NII/Ha little or
no HeII emission high excitation object ?
little or no NII HeII present
  • Gurzadyan (1988) related the excitation class of
    the nebula to the temperature of the central star
    as well as the radius Gurzadyan (1991).

14
Excitation class cont...
  • Ratag et al. (1997) used spectra for 110 PNe
    within 20 degrees of the Galactic centre
  • Excitation class defined by OII?3727/OIII?495
    9 for classes 5 and HeII ? 4686/HeI?5876 for
    classes gt5.
  • Distribution of 138 PNe in the Galactic Plane.
  • Excitation class defined by (OIII?5007OIII?4
    959)/Hß for low excitation objects and
    log((OIII?5007OIII?4959)/HeII) for high
    excitation PNe.

Number of PNe in each excitation class as
published in Gurzadyan and Egikyan (1991)
15
Excitation class cont
  • MASH does not compose of many medium excitation
    PNe.
  • Same as found in LMC by Reid Parker (2006)
  • Plot of OIII flux against excitation class of
    Escudero et al. (2004) sample

16
Other avenues for this data
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