I was reading this article (https://www.vice.com/en/article/z34883/scie-discover-huge-extragalactic-structure-in-zone-of-avoidance) and it talks about how a new galaxy cluster is named “VVVGCl-B J181435-381432”
Does naming a galaxy cluster like this really help people in this field of study know what it is they’re talking about?
In: 24
There are way too many celestial bodies to give a “normal” name, though they can have those. It’s just much easier to describe what “part of the sky” the body is. Those codes are more of a coordinate than a name. Different orgs will use different naming conventions.
The most popular one, which is probably the one you saw, is the International Astronomical Union. It uses a combination of unique name/code, and coordinates.
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Nebulae, Galaxies, and Other Objects
The designation of astronomical objects beyond the Solar System should consist of at least two parts — a leading acronym and a sequence value.
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An acronym is a code specifying the catalogue or collection of sources, conforming to the following rules, among others:
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It should consist of at least three characters (letters and/or numerals, avoiding special characters).
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The acronym must be unique.
Acronyms should not be excessively long.
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Sequence: a string of usually alpha-numerical characters that uniquely identify the source within the catalogue. Common values for the sequence are:
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Running number.
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Based on the coordinates of the object. Equatorial Coordinates shall always be preceded by J if they are for the standard equinox of J2000.0.l
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There is such a massive amount of known and catalogued stars and planets that naming them with actual names is really kinda pointless in most cases. So they give them serial numbers, which can be looked up in a catalogue to see where it’s located etc.
Because there is a shit ton of them.
If we were to give them all a unique “normal” name it would take forever and be impossible to keep track of.
Instead we give them that string of numbers and letters, which corresponds to things like the area of the sky they are in, how bright they are, etc etc.
There are millions of things that we see in the night sky, we can’t give them all normal-sounding names, so we set a standard naming convention based on it’s discovery
The first set (VVVGC1-B) refers to the survey that discovered it. Here, the VVV survey, **G**eneral **C**atalog 1B was what recorded it
The second part refers to it’s sky location. J denotes the coordinate system (called J2000) and the numbers represent the center of the object in that coordinate system (right ascension of 18°14’35”, declination -38°14’32”)
So, using this naming convention, we not only have a pretty much unique naming system for anything we find, but also it tells some basic information about it as well
The most prominent visible ones identified early in history are Messier Objects, M1 into M100s https://en.wikipedia.org/wiki/Messier_object beyond these are millions of other objects further cataloged by more complicated reference number systems. Some highlights:
M1 is the crab nebula https://en.wikipedia.org/wiki/Crab_Nebula
M31 is the Andromeda Galaxy https://en.wikipedia.org/wiki/Andromeda_Galaxy
M45 is Pleiades/Subaru https://en.wikipedia.org/wiki/Pleiades
And so on
Because space is too big. There are trillions of galaxies, and hundreds of billions of stars per galaxy. Even if we only uniquely identify a tiny fraction, that’s still hundreds of millions of stars, and there are only about ten thousand astronomers. There are better things to spend time on than constantly thinking up names and checking if they’ve already been taken.
Some stars do have names though, especially the brightest ones in the sky, which have been known since antiquity. Another way a star could get named is if there’s something that makes it particularly interesting.
If you take a look at the [IAU paper on Naming of Astronomical Objects](https://www.iau.org/public/themes/naming/) you see that this attempt at standardization is relatively new.
>**In 1982**, the United Nations, at its “Fourth Conference on the Standardization of Geographical Names” held in Geneva, recognized the role of the IAU by adopting its Resolution 13 on Extraterrestrial feature names (p.33)
this is still not fully agreed on.
>At its **inaugural meeting in 1922** in Rome, the IAU standardized the constellation names and abbreviations.
So people have been arguing about this for a long time, but at least the number / letter system gets rid of language issues (like a different name for every visible object in every language group)
In the section about [naming objects outside the solar system](https://www.iau.org/public/themes/naming/#outss) it suggests a two part name
* Leading acronym (letters – all caps)
* Sequence value (numbers)
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> **An acronym is a code specifying the catalogue** or collection of sources, conforming to the following rules, among others:
> It should consist of at least three characters (letters and/or numerals, avoiding special characters).
> The acronym must be unique.
> Acronyms should not be excessively long.
*************
> **Sequence: a string of usually alpha-numerical characters** that uniquely identify the source within the catalogue. Common values for the sequence are:
> Running number.
> Based on the coordinates of the object. Equatorial Coordinates shall always be preceded by J if they are for the standard equinox of J2000.0.
**NOW ON TO THIS SPECIFIC GALAXY**
The original paper [preprint on ARXIV – Unveiling a new structure behind the Milky Way](https://arxiv.org/abs/2210.16332) says the following.
>Our aim is to decipher the nature of the overdensity located behind the Milky Way, **in the tile b204 of the VVV survey.** Methods. We studied an area of six arcmin around a galaxy concentration located at l = 354.82° and b = -9.81°.
So the acronym of **VVVGCl-B** references the VVV survey, and tile B204.
They chop up the night sky into a grid of little boxes, and this is where they pointed the telescope for this object.
The “sequence value” of **J181435-381432** has the **letter J** which indicates that the numbers following are “standard equatorial coordinates.
I can’t give you more info on the coordinate system
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