Luminosity Functions: Globular Clusters

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Luminosity Functions Globular Clusters
Planetary Nebulae

• Astronomy 8400
• December 4, 2007
• Saida Caballero

http//antwrp.gsfc.nasa.gov/apod/
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Overview

• Globular Clusters
• Technique overview
• Current research
• Planetary Nebulae
• Technique overview
• Current research
• Summary

http//antwrp.gsfc.nasa.gov/apod/
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Globular Clusters Basic Technique

• Assume luminosity function is the same for every
  system.
• 1953 Noticed by Shapley in MW, LMC M31
• Fit GCLF
• Find to determine distance
• Applies mainly to ellipticals
• Distance Range 1kpc-100Mpc

Richtler 2003
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Globular Clusters Problems Errors

• Need well sampled GCLF peak
• Calibration Assumed universality of TOM
• Reddening extinction
• Different stellar populations
• Metallicity
• Photometric errors
• Foreground background objects

http//press.ucsc.edu/text.asp?pid1007
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Globular Clusters Current ResearchNantais, 2006

• NIR survey of MW, M31 Sculptor Group spirals
• NGC 300 intrinsically fainter or further away

http//www.atlasoftheuniverse.com/galgrps/scl.html
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Planetary Nebulae Basic Technique

• Logarithmic LF at low mag.
• Sharp cut off mag. at bright end
• Assume same for every system
• Emission lines
• Distance Range 1-10Mpc

Binney Merrifield, p. 418
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Planetary Nebulae Problems Errors

• Photometric Error
• Foreground extinction reddening
• Fit of PNLF
• Intracluster PNe

Feldmeier 2007
Crenshaw 2007
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Planetary Nebulae Current ResearchFeldmeier, et
al., 2007

• OIII ?5007 survey of 5 nearby galaxies
• Determined distances for 3 and limiting distances
  for 2
• Compared with Cepheid SBF dist. calibrations of
  SNe Ia found to be consistent ? not population
  dependent

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Summary
http//antwrp.gsfc.nasa.gov/apod/

• Peak mag. of GCLF as distance indicator agrees
  well with other distance measurements.
• Improving accuracy by observing in different
  wavelengths
• Cut off mag. of PNLF also serves as a good
  distance indicator and easier to determine
  because only need the bright end
• More universal calibrated for SN Ia than Cepheids

http//antwrp.gsfc.nasa.gov/apod/
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References

• Binney, J. Merrifield, M., Galactic Astronomy,
  Princeton University Press Princeton, NJ (1998)
• Ciardullo, R., Lect. Notes Phys., 635, 243
  (2003)
• Crenshaw, M., Lecture 5, slide 3 (2007)
• Feldmeier, et al., ApJ, 657, 76 (2007)
• Nantais, J.B., et al., AJ, 131, 1416 (2006)
• Richtler, T., Lect. Notes Phys., 635, 281 (2003)