Approximately how long does it take for a galaxy to form?

[Tanelorn]

TL;DR

Time needed for a Galaxy form

What is the consensus on how long it would take for a galaxy to form similar to the ones which I am reading about here with Z=20?
Galaxy formation time is probably of much interest right now.
Perhaps formation was much quicker shortly after the BB with higher gas densities?

https://www.space.com/james-webb-space-telescope-new-most-distant-galaxies

Does relativistic time dilation also need to considered when estimating the time needed in our years for galaxy formation?
https://www.space.com/quasar-clocks-universe-time-dilation

 

[pinball1970]

TL;DR Summary: Time needed for a Galaxy form

What is the consensus on how long it would take for a galaxy to form similar to the ones which I am reading about here with Z=20?
Galaxy formation time is probably of much interest right now.
Perhaps formation was much quicker shortly after the BB with higher gas densities?

https://www.space.com/james-webb-space-telescope-new-most-distant-galaxies

Does relativistic time dilation also need to considered when estimating the time needed in our years for galaxy formation?
https://www.space.com/quasar-clocks-universe-time-dilation

Those z=20 have not been confirmed IIRC. A Z=13 has been confirmed fairly recently, 280 million years after the BB.
@Ibix posted recently on this.

EDIT: I was a bit out z closer to 14 and 300 million years after the BB. https://arxiv.org/abs/2405.18485

 

[Jaime Rudas]

TL;DR Summary: Time needed for a Galaxy form

Does relativistic time dilation also need to considered when estimating the time needed in our years for galaxy formation?

In this regard, it is worth mentioning that there is a difference between relativistic and cosmological time dilation, as explained in chapter 4.1 of https://arxiv.org/pdf/astro-ph/0310808

 

[PeterDonis]

Does relativistic time dilation also need to considered when estimating the time needed in our years for galaxy formation?

No. The time being used is FLRW coordinate time, which is the same as proper time for comoving observers. That is the time standard for cosmology and it is the same back then as now.

 

[Tanelorn]

Thanks Peter.
I presume that time needed for galaxy formation is one of the hottest topics right now in Cosmology.

 

[pinball1970]

Thanks Peter.
I presume that time needed for galaxy formation is one of the hottest topics right now in Cosmology.

It was pretty hot years ago to the community who were researching. They had theory, models, simulations but observations that were not fitting in.
Its interesting and exciting to follow as a bystander

https://arxiv.org/abs/1506.01377

 

[Tanelorn]

Pinball, I have not looked into it at all yet. Are they able to make the time needed for galaxy formation work and be consistent with the age of the Universe?
I hope they are not being told the time that it needs to be beforehand :)

 

[Mordred]

Interesting article Pinball1970. Thanks for sharing. I've also been following the related studies but hadn't read this one.

 

[pinball1970]

Interesting article Pinball1970. Thanks for sharing. I've also been following the related studies but hadn't read this one.

Pf guys on here can give you much better info in terms of chronology and theory Vs Observation.

@Orodruin @Ibix @Drakkith and @PeterDonis @ohwilleke and others.

 

[Mordred]

Agreed PF has numerous skilled members including those you mentioned. When I have questions it's a good site to ask.

 

[ohwilleke]

I presume that time needed for galaxy formation is one of the hottest topics right now in Cosmology.

It is a very important question in cosmology, but that doesn't necessarily mean that it is one of the "hottest topics" in terms of research work.

 

[phyzguy]

TL;DR Summary: Time needed for a Galaxy form

Perhaps formation was much quicker shortly after the BB with higher gas densities?

I think this is exactly right. I'm not an expert in this field, but at Z=14, the gas density was over 3000 times higher than today. So to me it is not surprising that things could proceed more quickly. I suspect we are just underestimating how quickly a galaxy can form at those densities.

 

[Nik_2213]

As galaxies and big central quasars seem 'correlated', this may be relevant.

A black hole of inexplicable mass: JWST observations reveal a mature quasar at cosmic dawn​

https://phys.org/news/2024-06-black-hole-inexplicable-mass-jwst.html