• Question: What's your favourite galaxy?

    Asked by to Nat, Nate, Roberto, Sam, Sarah on 14 Jun 2014. This question was also asked by .
    • Photo: Sarah Casewell

      Sarah Casewell answered on 14 Jun 2014:

      I’m not an extragalactic astronomer, so I don’t study galaxies, but I think my favourite to look at is M100. It’s a face on to us spiral, and it just looks so pretty!

    • Photo: Nate Bastian

      Nate Bastian answered on 15 Jun 2014:

      I have two favourites, the first is M51 (also known as the “Whirlpool galaxy” -http://en.wikipedia.org/wiki/Whirlpool_Galaxy). This is a spiral galaxy, similar to our own, that has recently undergone an interaction with another galaxy (the yellowish circle on the image). This interaction has caused a huge burst of star-formation within M51, and is also the cause of the beautiful spiral structure seen in the images.

      My other favourite is M82 (http://en.wikipedia.org/wiki/Messier_82). This galaxy has also recently undergone a starburst, but unlike M51, the starburst in M82 was confined (mostly) the very centre of the galaxy. This starburst then drove a massive gas wind (like a bubble) out of the galaxy, which is what you see in red in the image. My favourite image of M82 was made by a friend of mine, Mark Westmoquette (http://www.noao.edu/image_gallery/html/im0860.html).

    • Photo: Sam Connolly

      Sam Connolly answered on 15 Jun 2014:

      My favourite galaxy is called NGC1365. It’s a really pretty ‘barred’ spiral galaxy, which means it has a straight line of stars in the middle with spirals coming off the ends. But the reason I think it’s the most interesting is because it has a supermassive black hole in the centre which is actively sucking up a lot of gas. There are a lot of black holes doing the same in other galaxies, but the light from the gas from NGC 1365 is constantly changing in colour and brightness, more than most others. This means we can learn a lot about black holes from it by working out the reasons it’s changing, which are still not completely known.

    • Photo: Roberto Trotta

      Roberto Trotta answered on 16 Jun 2014:

      My favourite galaxy is different from any other galaxy you might have seen — the reason is that my galaxy is almost invisible! (and so, you wouldn’t have seen it even if you had looked at it!)

      It’s called “Segue I” and it’s actually very small, so that it’s called “a dwarf galaxy”. It’s very close to our own Milky Way, but it’s only been discovered in 2006 because it’s so small and faint and hence difficult to see.

      Segue I only contains about 1,000 stars, while a normal galaxy contains maybe 100 billion stars. You can see why it’s called a dwarf galaxy!

      The reason why I like Segue I is that it’s a fantastic galaxy for those who, like me, want to study dark matter.

      Most of Segue I is actually made of dark matter, we believe. And because there are so few stars in it, we can use Segue I to look for dark matter without being confused by the light emitted by the other stars. The idea is that if there is lots of dark matter particles in Segue I, every now and then they will bump into each other, and disappear by emitting flashes of high energy light, called Gamma rays. And since there are so few stars in Segue I, if we pick up any Gamma rays from it they are likely to come from the disappearance of dark matter, rather than from the stars. This would lead us to measure interesting properties of dark matter.

      We haven’t seen any of those signals yet, but we keep looking.

      And here is a picture of what Segue I looks like:

      Ok, I admit, it’s not very pretty… it’s mostly dark space! But that’s why it’s interesting! 🙂

    • Photo: Natasha Stephen

      Natasha Stephen answered on 18 Jun 2014:

      I am going to be boring and say that my favourite galaxy is our one, the Milky Way! It is our home and is so incredibly diverse as well, I don’t think we need to go any further to find a favourite!

Comments