Lenticular Galaxy – What is it?

Sombrero Galaxy

I love imaging galaxies and have some beautiful ones so far. Last year when I started astrophotography I discovered that it was possible to photograph galaxies that were millions of light-years away! On this page, though I want to focus on one kind of galaxy, the Lenticular Galaxy, and help you to understand what it is and why it is so important to astronomers.

A Lenticular Galaxy has a bulge in its center and a flat disc surrounding it. This kind of galaxy has no spiral arms. The formation of lenticular galaxies is not fully understood yet. However, astronomers believe that a lenticular galaxy is formed from two spiral galaxies colliding.

As we shall see lenticular galaxies are important to our understanding of the Universe and personally I have always found them to be quite appealing deep-sky astrophotography targets. I have managed to image a few of these and one example I have photographed is the Needle Galaxy.

Before we go further, in case you’re wondering, check out my guide on how you can get into astrophotography cheaply.

Let’s now look more closely at the form and importance of this kind of galaxy.

Why Are Lenticular Galaxies Important?

Astronomers study galaxies, in general, to better understand the organization and formation of matter in the Universe. Galaxies represent physics working on a huge scale, whereas quantum physics is the exact opposite. If we understand how galaxies formed and organized themselves into what we see today, together with what we learn about subatomic level physics, we can better understand how the Universe works. See this article, published by Nasa, for more information about how the James Webb Telescope will try to help us to understand the nature and formation of galaxies better and solve other related questions we have about the Universe.

Now let’s consider lenticular galaxies specifically and what we can learn from them.

Lenticular galaxies are important for several reasons:

  • They are the first quasi-stellar objects (QSOs) to be discovered and observed in 1923 by Edwin Hubble. This discovery helped Hubble make the statement that we live in an expanding universe.
  • Lenticular galaxies provide a unique observational perspective on how dark matter is distributed in space. There appears to be dark matter in the outer area of this type of galaxy in the form of a halo.
  • The study of lenticular galaxies can help astronomers understand the process of star formation (see this article published by Phys.org for more about this).

What are Lenticular Galaxies Made of?

A lenticular galaxy is composed of older stars because the theory is that they are the result of a collision between two spiral galaxies. This means that the galaxy must at least be as old as the oldest of the pair of original galaxies. In fact, more than that because we also need to add the time that was needed for the final galaxy to form after the collision. Check out my images of Markarian’s Chain where you can see a few lenticular galaxies.

Despite the above theory of how a lenticular galaxy is formed, there is much doubt and confusion about this question, some of these points are raised in this article by Sidney Van Den Bergh (1999).

When we observe a lenticular galaxy we are looking at a long period of the history of star and galaxy formation. This is what makes them so important to astronomers studying them.

These galaxies are not very common but they are more frequently found in clusters and especially in the Virgo Cluster.

If you are interested in improving your astrophotography, then go look at my 5 tips to take better astrophotos now.

And here is another page I’ve written for you if you want to know what is so great about astrophotography.

Lenticular galaxies are also known as lens-shaped galaxies

Lenticular galaxies are also known as lens-shaped galaxies. They are named so because of their resemblance to a lens or a lentil which is oval or elliptical in shape. This type of galaxy is the result of two colliding spiral galaxies, which form a new galaxy. Sometimes, other types of galaxies can collide to create lenticular galaxies too.

The lens-shaped galaxy has an outer disk that surrounds the nucleus and has an inner disk that contains young stars and dust. Lenticular galaxies have more gas and dust than other types of spiral galaxies since they are formed by two colliding ones.

Examples of Lenticular Galaxies

Lenticular galaxies are galaxies that have a disk, a bulge, and an extended halo.

Lenticular galaxies may look like elliptical galaxies to the naked eye, but they contain more stars and dust than elliptical galaxies. Lenticular galaxies do not typically seem to have active star formation, but some of the ones near the Milky Way may form stars because of their proximity.

The Spindle Galaxy

The Spindle Galaxy is a galaxy with a small bulge of stars near its center. It is located within the constellation of Coma Berenices and was discovered in 1845 by the British astronomer James Dunlop.

The Spindle Galaxy has been classified as a lenticular galaxy, but there are some astronomers who argue that it is not a lenticular galaxy at all, but rather a dwarf spiral galaxy.

There are two main arguments for why it may not be a lenticular galaxy: first, the disk of the Spindle Galaxy does not have enough gas to create new stars and second, it does not have an outer ring of old red stars that would be associated with elliptical galaxies.

The Sombrero Galaxy

The Sombrero Galaxy (see my photo at the beginning of this article), is classified as a lenticular galaxy although some prefer to classify it as a spiral galaxy.

NGC 6861

Lenticular Galaxy
NGC 6861, is a galaxy discovered in 1826 by the Scottish astronomer James Dunlop.
Copyright NASA/ESA Hubble Space Telescope

Lenticular Galaxies and How They Are Shaping the Future of the Universe

Lenticular Galaxies are galaxies that are unique for their disk-like shape instead of the spiral or elliptical shapes. They also have a unique characteristic – they host two supermassive black holes which, as they start to orbit each other, can cause gravitational waves and produce bright bursts of light.

Lenticular Galaxies are shaping the future of the universe as we know it.

How Did Lenticular Galaxies Come to Be?

Lenticular galaxies are a great celestial spectacle. They are also rare to come across in the universe. So how did these galaxies come about?

The common theory is that lenticular galaxies are formed by collisions between two or more galaxies. The collision causes the gas and stars to accumulate in one area, producing a disk shape. These disks are usually seen when looking at them from one side, but if you view them from the other side, it looks like a spiral galaxy.

Conclusion

Lenticular galaxies are important for understanding the universe because they can tell us about its history.

Firstly, they appear to be relatively rare – there are only about 25 known lenticular galaxies in the entire universe. Secondly, these galaxies contain some of the oldest stars in the universe. Thirdly, they can provide insight into how gas is distributed in the galaxy. Personally, one of the favorites that I’ve been able to photograph is the Sombrero Galaxy, which looks like a giant UFO!! If you want to photograph galaxies you will need to buy a good quality telescope, but how much should you pay? Find out how much different telescopes cost here.