Astro Group Seminar: Satellite Galaxy Evolution and Student Advice

New Hubble image of galaxy cluster Abell 1689. Credit: ESA/NASA/Hubble

New Hubble image of galaxy cluster Abell 1689. Credit: ESA/NASA/Hubble

Every Thursday afternoon (apart from the first one in a month) the Astrophysics Group at MSSL has a seminar. These seem to mostly be by speakers from different institutions and about a wide range of topics. After the main seminar the speaker also sits down with the PhD students to answer any questions and give career advice. I enjoyed both sections and have summarized both in this post.

Although I have been at MSSL for three weeks now, due to a welcome event at UCL’s main campus and the beginning of a month, last week was my first seminar.  The speaker was Dr Anna Pasquali from the University of Heidelberg who talked about satellite galaxy evolution.

Galaxies are collections of hundreds of billions of stars, like our own galaxy the Milky Way, but they do not exist in isolation. Throughout the observable universe, galaxies exist in groups we call clusters. Our Milky Way is part of the Local Group. Satellite galaxies are the outer, lower mass members of these clusters, as opposed to central galaxies (which, as their name suggests, exist in the centre of these clusters).

Dr Pasquali’s current research is looking at how satellite galaxies change over time (their evolution) in terms of their star formation history. She is investigating whether their own intrinsic properties (nature) or their position in the cluster (nurture) is more important to their overall evolution. This is quantified by the amount of time it takes for star formation in the satellite galaxy to be suppressed.

Suppression of star formation can be split into two categories, quenching and strangulation. Dr Pasquali used ‘strangulation’ when describing hot gas being removed from the galaxy, stopping future star formation because hot gas must cool before it can collapse to form new stars. She used ‘quenching’ when describing cold gas being stripped from the galaxy, stopping star formation on a much shorter timescale because this is the gas that would have led to the next generation of stars. She made it clear that this distinction is not fully formed, especially as the actual process of strangulation is not yet well understood. In fact “we don’t know how to describe strangulation with equations yet”.

While the astrophysics content of the seminar was very interesting, it was not directly relevant to me as it’s a different area. For this reason I found the student session afterwards more helpful as Dr Pasquali was very happy to offer lots of advice. The points I found particularly interesting were:

  • Data can only take you so far. There will be error bars that you cannot remove, so know when to stop!
  • To research for 30 years you need plenty of ideas. Where do you get these? By talking to and collaborating with people. Talk to everyone.
  • Americans are traditionally more positive in the face of problems, learn from this and spend a few years researching in the US if you can.
  • Being a woman in astronomy research is difficult. Speak up, let people know you’re there.

I want to finish this post with my favourite piece of advice from that session:

“If you want to continue in research, this is it: one problem after another that you have to solve.”

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2 thoughts on “Astro Group Seminar: Satellite Galaxy Evolution and Student Advice

  1. Nancy Hine says:

    Useful advice for all us newbies. Also related to my topic, so interesting for me.

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