<p>There definitely is no definition of what is low and what is high redshift — it is always seen in relation to something. An astronomer working in, say, the interstellar medium of the Milky Way ($z\sim0$) might talk about the ISM of a $z\sim2$ galaxy as being high redshift, whereas another astronomer working the reionization of the Universe (which took place around $z\sim10$) would consider $z\sim2$ to be low redshift. A cosmologist working in the CMB or inflation, however, would probably call $z\sim10$ low redshift. It all depends on the context. </p>

<p>Nevertheless I think that <em>most</em> people would consider $z\lesssim0.1$ to be low redshift. </p>

CC BY-SA 3.0
2016-12-28T23:15:58.667Z
2016-12-28T23:15:58.667Z
pela
<p>I'm curious about the difference between low redshift and high redshift universe. Is there any defined limit of redshift beyond which we call things high redshifted?</p>

<universe><redshift><quasars>
What is high redshift?
Syed Ali Mohsin Bukhari
# What is high redshift?

(Asked by: username_0 on 2016-12-28)

I'm curious about the difference between low redshift and high redshift universe. Is there any defined limit of redshift beyond which we call things high redshifted?

**Tags:** universe, redshift, quasars


---

## 1 answers

### Answer by username_1 on 2016-12-28. Score: 3 | Accepted answer

There definitely is no definition of what is low and what is high redshift — it is always seen in relation to something. An astronomer working in, say, the interstellar medium of the Milky Way ($z\sim0$) might talk about the ISM of a $z\sim2$ galaxy as being high redshift, whereas another astronomer working the reionization of the Universe (which took place around $z\sim10$) would consider $z\sim2$ to be low redshift. A cosmologist working in the CMB or inflation, however, would probably call $z\sim10$ low redshift. It all depends on the context.

Nevertheless I think that *most* people would consider $z\lesssim0.1$ to be low redshift.


---

