Questions tagged [galaxy]
Questions regarding systems of large numbers of stars held together by gravity.
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How to count observable number of galaxies at a given latitude considering interstellar extinction?
If galaxies are uniformly distributed in space, then in the absence of extinction, the number of galaxies per square degree brighter than magnitude m is given by $$\log_{N_0}(m) = 0.6m + C$$
How will ...
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Can we detect gravitational waves from galaxies merging?
How strong are the signals and how long do waves persist.Can ancient mergers be detected?
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Is this a galaxy?
I took a photo last night (Wed 3 July 2024) around 23:45 (BST) from a small town outside of Chesterfield, UK.
I uploaded it to a site to identify the stars which is shown via the green annotations in ...
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Dual mode in SExtractor
I wanted to use SExtractor for source detection. I have 7 NIRCam filter data from the JWST CEERS catalogue. How can i proceed with the source detection. I read about using dual image mode in which a ...
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Using SExtractor for JWST data
I am new to this tool for catalogue creation(SExtractor). I want to know about how to set parameters for the extraction for JWST data.
The parameter file looks like this.
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calculating the color of a galaxy and making the k correction
I want to know if this is correct:
I have in my dataset: $u_{mag}, u_{mag_{err}}, r_{mag}, r_{mag_{err}}$
Calculating the $u_{r_{color}}$:
$u_{r_{color}} = u_{mag} - r_{mag}$
$u_{r_{color_{err}}} = u_{...
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Are the rotational axes of galaxies ever aligned?
My friend thinks that the expansion of the the universe should cause the galaxies on the same side of the sky to be aligned.
I don't believe that because I haven't seen any evidence of it, but he came ...
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What is a "re-simulation"?
In the context of galaxy formation and evolution simulations, what is a re-simulation and how is it different from a simulation?
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Finding the algular size of galaxy cluster when given the RA and dec cordinates of all the galaxies in the cluster
I have the RA and dec values of all the galaxies in a cluster and i need to find its angular size i do not know how to calculate it
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Why is the metallicity of dwarf galaxies low?
The "Astronomy Picture of the Day" today sent me down a rabbit-hole. It had a picture of Leo I, with a note that it may have a supermassive black hole at the center, so I went to Wikipedia ...
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The distribution of mass in the bullet cluster
Can someone point me to a database which contains the luminous and gas mass distribution of the bullet cluster?
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How can I convert luminosity from [erg/s/Hz] to [erg/s]
I have the dust-corrected luminosity in the Ks band in the unit erg/s/Hz. I want to convert it to erg/s. I would like to know which method is correct:
$L[erg/s]=L[erg/s/Hz]\times(C/\lambda)$
$L[erg/s]...
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Does anybody know of a top down map of andromeda in the style of existing (artistic) milky way maps?
I'm looking to make a digital model of the local group of galaxies and I can't find a good representation of the Andromeda galaxy from a top-down view.
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Are galaxies growing, shrinking or stable?
When I look at spiral galaxies they look a bit like the whirlpool of water going down a sink and I wonder if eventually they shrink to a small point (or a giant black hole?). On the other hand they ...
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Efficient method for generating combined spectra from N-body simulation data using Python (convolution)
(I asked this same question also in StackOverflow, due to being both astronomy/coding problem, here link : https://stackoverflow.com/questions/78166419/efficient-method-for-generating-combined-spectra-...
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