Magnitude vs Redshift Supernova 1a

In summary, there is a discrepancy between the two graphics provided by the links. The first link shows a plot of m(z) as a function of redshift, using the equation m(z) = constant + 5*log(1+z - (1+z)^(1/2)). The second link, on page 7 of the arXiv paper, also shows a plot of m(z), but it is linear and does not diverge at z=0. It is suggested that the reason for this difference could be due to the inclusion of a filter transmission function in the definition of magnitude, as mentioned in the paper by Bergstrom, Goobar, Cosmology and particle astrophysics. It is important to note the
  • #1
wikiwert
2
0
The following two graphics are supposed to be the same, but they are not (there is something I am not getting right). After the calculation of m ( z ) (magnitude as a function of redshift) I get the plot of the first link:

-Plot at the bottom (NOT the last one) of
http://www.rqgravity.net/Supernova m (z) = constant + 5*log ( 1 + z - (1 + z)^(1/2) )

-Page 7 of http://arxiv.org/abs/astro-ph/9812473
Here the plot is linear; does not diverge in z = 0.

Maybe the answer is that in the second case, the definition of the magnitude includes a filter transmission function (as hinted in Bergstrom, Goobar, Cosmology and particle astrophysics)? I have to hand in this yesterday : P.
 
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  • #2
Look carefully at the calibration of the horizontal axis of the graph on page 7 of the arXiv paper.
 
  • #3
Yes...thank you.
 

1. What is a magnitude vs redshift supernova 1a?

A magnitude vs redshift supernova 1a is a type of supernova that is used to measure the expansion of the universe. It is a specific type of supernova that occurs when a white dwarf star in a binary system accumulates material from its companion star until it reaches a critical mass and explodes.

2. How is the magnitude of a supernova 1a measured?

The magnitude of a supernova 1a is measured by comparing its brightness to other objects in the sky. This is done by using a standard candle, which is an object with a known, fixed brightness. By comparing the brightness of the supernova to the standard candle, scientists can determine its magnitude.

3. What is the relationship between magnitude and redshift in supernova 1a?

The relationship between magnitude and redshift in supernova 1a is known as the Phillips relation. It states that the brighter a supernova 1a appears, the longer its light takes to reach us, meaning it has a higher redshift. This relationship is important in determining the distance and expansion rate of the universe.

4. How does redshift affect the accuracy of measuring the magnitude of supernova 1a?

The redshift of a supernova 1a can affect the accuracy of its magnitude measurement because it causes its light to shift towards longer, redder wavelengths. This can make the supernova appear dimmer than it actually is, leading to an underestimation of its magnitude and distance.

5. What is the significance of studying magnitude vs redshift supernova 1a?

Studying magnitude vs redshift supernova 1a is significant because it allows scientists to measure the expansion rate of the universe and track its evolution over time. This data can also help to determine the nature of dark energy, the mysterious force believed to be responsible for the accelerated expansion of the universe.

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