I A glitch in Jorrie’s Cosmo-Calculator?

  • I
  • Thread starter Thread starter JimJCW
  • Start date Start date
  • #151
Let’s summarize the situation:

(1) The glitch associated with Dnow(z) discussed in Post #1 is eliminated in LightCone8 (see Post #102).

(2) The error associated with Ω’s in Jorrie’s calculator discussed in Post #109 is fixed in LightCone8 (see Post #148).

(3) The difference in calculated Dnow(z) using LightCone8 and ICRAR still needs to be resolved (see Post #102). I believe I can do that, but first, I need @pbuk and @Jorrie to change the following conversion,

1 pc = 3.262 ly​

in LightCone8 to,

1 pc = 3.261563777 ly​

This will make direct comparison of results from the two calculators possible.
 
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  • #152
JimJCW said:
(3) The difference in calculated Dnow(z) using LightCone8 and ICRAR still needs to be resolved (see Post #102). I believe I can do that, but first, I need @pbuk and @Jorrie to change the following conversion,

1 pc = 3.262 ly​

in LightCone8 to,

1 pc = 3.261563777 ly​

This will make direct comparison of results from the two calculators possible.
This could surely improve accuracy for comparison purposes, but take note that Lightcone8 does not allow ##\Omega_r## to be identically zero, but only a minimum value through setting ##z_{eq} = 999999##.

(This with reference to your Post #102, where you compared calculators for ##\Omega_r = 0##)

At low redshift a tiny radiation density makes negligible difference, but not so for high redshift work.
 
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  • #153
Jorrie said:
This could surely improve accuracy for comparison purposes, . . .

My goal is to be able to say,

Calculation results from Lightcone8 and ICRAR are consistent.​

This is true for the following quantities,

LightCone8
ICRAR
z0.020.02
Scale (a)9.803921569E-019.803921569E-01
H(z)6.837765717E+016.837765717E+01
OmegaM3.217304253E-013.217304253E-01
OmegaL6.781722253E-016.781722253E-01
OmegaR9.734946123E-059.734946125E-05
OmegaT1.000000000E+001.000000000E+00

but not for Dnow and Dthen:

LightCone8ICRAR
z0.020.02
T Gyr1.351246087E+011.351276116E+01
Dnow Gpc8.808897954E-028.810076113E+01
Dthen Gpc8.636174465E-028.637329523E+01
rho kg/m38.782193743E-278.782799071E-27

I believe changing the conversion to ‘1 pc = 3.261563777 ly’ in LightCone8 will resolve this discrepancy.
@pbuk
 
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