All Questions
Tagged with redshift astrophysics
11
questions
0
votes
1
answer
92
views
Does a cosmological redshift occur within our local group, of galaxies?
I know that it is not supposed to be expanding but space is space and it is expanding everywhere else outside it so why not inside it too, and gravity just holds everything back.
I suppose if it is, ...
- 171
2
votes
1
answer
134
views
Why are distant type Ia supernovae dimmer than expected?
Why are the (extremely) distant type Ia supernovae dimmer than expected?
Relative to what? Their cosmological red shift? Well, what else.
Please don't just say "Because the expansion is ...
- 171
6
votes
1
answer
135
views
Classifying 3C273 as a quasi-stellar object
I am currently reading A Brief History of Time and Chapter 6 about black holes.
Now, here it says
He found it too large to be caused by a gravitational field: if it had
been a gravitational redshift, ...
- 191
1
vote
1
answer
4k
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How to find the distance between two galaxies from ra and dec and redshift [duplicate]
I have ra and dec and corresponding redshift of galaxies. I would like to calculate the distance between two galaxies.
I did like this to find the nearest neighbour galaxies.
Suppose I am trying to ...
- 11
1
vote
1
answer
58
views
redshift in astrophysical plots [closed]
Why do astrophysicists often use redshift in plots? Why it is important to know how an astrophysical object evolves in function of redshift? I was seeing an "cosmological time per redshift ...
0
votes
0
answers
88
views
What was the energy/wavelength/frequency of the CMB when first emitted/released?
Given the z redshift of 1089, and the temperature difference between then and now of about 1089, I tried scaling the ev, freq. and wavelength by 1089....
Is that right?
I get a freq. of about 240 ...
- 5,307
7
votes
0
answers
256
views
Get the expression of probed volume between 2 redshifts
1) I can't manage to find/justify the relation (1) below, from the common relation (2) of a volume.
2) It seems the variable r is actually the comoving distance and not comoving coordinates (with ...
user16492
2
votes
1
answer
448
views
how to calculate distance between galaxies in the distant past
for example, assume there is a high redshift galaxy called "A" with z=6, so how to calculate the distance between us and another galaxy B when the light left the galaxy A?
For example, say B has a ...
- 23
-4
votes
1
answer
232
views
What is the time dilation less a magnetic field?
Does time dilation drop off like a gravity or does resemble a magnetic field model?
Could a smaller body with a magnetic field have more time dilation then a larger body without and to what degree?
- 1
4
votes
1
answer
82
views
Photometric redshift [closed]
I have decided to do undergraduate thesis on "estimating photometric redshift" or something related to this using machine learning. Reading previous papers, I have come to know that work has been done ...
- 141
5
votes
2
answers
341
views
Is there another explanation, apart from the doppler effect, for the redshift observed in distant galaxies?
On episode 10 of the original Cosmos TV series, Carl Sagan mentions that some scientist don't agree that the redshift observed in distant galaxies is evidence of the big bang, stating that probably ...
- 2,695