Calculating luminosity density of the universe

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SUMMARY

The discussion focuses on calculating the luminosity density of the universe using the Schechter parameters obtained from the Sloan Digital Sky Survey (SDSS). The parameters include a = -1.16, M* = -20.80, and Phi* = 1.50. The formula used is l = Phi*L*Gamma(a+2), where the user initially confused absolute magnitude M* with luminosity L*. The correct approach involves understanding the relationship between absolute magnitude and luminosity, which is crucial for accurate calculations.

PREREQUISITES
  • Understanding of Schechter function parameters
  • Familiarity with absolute magnitude and luminosity concepts
  • Knowledge of Gamma function values and their applications
  • Basic proficiency in astrophysics and cosmology
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  • Research the relationship between absolute magnitude and luminosity in astrophysics
  • Learn how to apply the Schechter function in luminosity density calculations
  • Study the implications of the Sloan Digital Sky Survey data on cosmic structures
  • Explore error estimation techniques in astrophysical measurements
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Astronomy students, astrophysicists, and researchers involved in cosmological studies or those interested in luminosity density calculations.

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Homework Statement



l = Phi*L*Gamma(a+2)

b)

The Sloan Digital Sky Survey (SDSS) has recently measured the following Schechter
parameters in the r passband: a = -1.16 +/- 0.03, M*= -20.80 +/- 0.03, Phi* = (1.50 +/-0.13). Given that the sun has absolute magnitude M = 4.62 in the SDSS r band, calculate the luminosity density in this band in solar units. Estimate the error on this quantity.
Gamma(0.84) = 1.122, Gamma(0.81) = 1.153, Gamma(0.87) = 1.094.




Homework Equations





The Attempt at a Solution



I done the entire question and then realized i had made a grave error. And this is what I think it is; I took L* as being -20.80 +/- 0.03 ie M*, and I am pretty sure this is wrong. Luminosity confuses me and I'm not sure how to relate the absolute magnitude M* to the Luminosity L*. I know that L* is supposed to be in the order of 10^10. Can anyone out there help? Its kind of urgent (due in tomorrow!).
 
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Never mind. Problem solved
 

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