Questions tagged [redshift]
Questions related to the phenomenon whereby electromagnetic radiation (such as visible light) generated by an object moving away from an observer will have increase in wavelength (i.e. shifted toward the red end of the spectrum) once it reaches the observer.
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questions with no upvoted or accepted answers
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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
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How far away must galaxies be before current telescopes can no longer measure how quickly they are rotating around one another or internally?
What is the distance limit and does it depend on the size of the galaxy and on noise and interference from gas clouds and our own Milky Way?
user50623
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How does SDSS estimate photometric redshift of sources?
I'm looking through the data in SDSS DR 12:
...
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K-correction vs resizing photometric bands
Is there a difference between a K-correction (see Wiki https://en.wikipedia.org/wiki/K_correction) and simply "resizing" the bands, e.g. the 2-10 keV x-ray band, with the redshift? I've read ...
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Redshift distance proportionality at high Z and need for "mighty mouse" galaxies?
Allegedly supported by some evidence from the new James Webb space telescope physicist Eric Lerner has written an article that have garnered some attention. He writes that:
"Put another way, the ...
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Kaggle dataset for Photo-Z estimation?
I would like to use the dataset for this kaggle but the competition was private, is closed and I have been unable to contact anyone directly.
The challenge is machine learning for photo-z estimation ...
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Using prospector for jwst data
I am working with JWST data. I want to estimate the redshift of the sources I have identified with SEXtractor with the help of prospector. Can somebody guide me in this?
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JWST Early Black Holes: Gas Collapsed To Metallic Hydrogen Core?
I was reading an article about early black holes found by JWST at Redshift 9. And saw that there was wonder at how large amounts of gas could collapse into a black hole as a theory.
So my question is ...
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Empirical Constraints on the Time Evolution of Cosmological Redshifts
The standard model of Cosmology predicts that the redshift of a single source at fixed comoving distance varies with observation time according to
$$ \dot z = \left( 1+z - \frac{H(z)}{H_0} \right) H_0....
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How does one estimate the mass of a galaxy using the Balmer break region?
I am currently reading the recent astrophysical paper "A population of red massive galaxies ~600Myr after the Big Bang'.
In the first paragraph/abstract it mentions, "It has been difficult ...
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2
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Plotting galaxies in 3-D
Suppose I have a catalogue of galaxies in a .dat file with each row representing information about a galaxy: right ascension of the galaxy, declination of the ...
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How to find the scale factor on given time in the future if initial distance between source and destination is known
Assume the received redshift $z$ of a photon is known. We then can calculate the initial distance (when the received photon was emitted), the light Travel Distance, the current Distance (proper ...
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Is cosmological redshift caused due to expansion of space or distance traveled by light?
If the universe wasn't expanding, would light still be redshifted after traveling some distance?
Is there a way of being sure that it's the expansion that causes light to redshift and not just a ...
- 427
2
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Definition of space - to cope with "space expansion"
I've searched quite a lot but found no satisfying definition, so please:
How do we actually define space when talking of "space expansion"? Isn't it just a metric, a dimension we measure, instead of ...
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Minimum apparent magnitude of galaxy
currently I'm working on astronomy problem which deals with finding redshift of a galaxy. But the first part asks to derermine apparent magnitude of a galaxy:
Find what should be the minimum ...
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