Dawn of the Red and Dead

November 3, 2016

The monthly meeting of Sydney City Skywatchers is held in the Discovery Room at Sydney Observatory on the first Monday of each month. Hear a special presentation from a guest speaker, learn about upcoming events, hear member’s reports and astronomy news. Meetings commence 6:30pm and non-members are welcome to attend for a donation of $5. More about Skywatchers here.

Next Meeting is Monday November 7, 2016. This will be the last meeting in 2016 with a guest speaker, December’s meeting is the Christmas Party!

Talk Title: Dawn of the Red and Dead: Understanding the Formation and Evolution of Massive Galaxies

The distribution of hot gas in a group of red and dead galaxies. A Chandra X-ray image with the hot gas coloured blue. If the stars were visible the galaxies would look red! Courtesy NASA.

With Hubble Space Telescope’s upgraded and most sensitive detectors, astronomers have discovered red and dead galaxies that stopped forming stars eleven billion years ago. It came as a surprise that only three years after the big bang the variety in the colour and shapes of galaxies was already similar to the present day universe. Even more surprising was the fact that massive elliptical galaxies are extremely compact in comparison with their local counterparts. How these galaxies became so massive and compact in such a relatively short time remains a big mystery. In this talk I will discuss recent research that uses the biggest telescopes on earth and in space to solve this problem. I will go into some of the details of how we measure the stellar populations in galaxies that are only a few pixels on our detectors. I will finish by discussing our latest understanding of galaxy formation and evolution. How do massive red and dead galaxies form? How do they die, and what happens in their afterlife.



Speaker’s Bio: Jesse van de Sande finished his Master’s degree in Astronomy in 2009, after which he started working with Prof Marijn Franx at Leiden Observatory in the Netherlands. For his PhD thesis, he used the Hubble Space Telescope and ESO’s Very Large Telescope in Chile to investigate the formation and evolution of massive galaxies in the early Universe. His work showed that high-redshift galaxies are truly very massive and structurally very different from present-day galaxies, for which he got awarded his doctoral degree in October 2014. After that he moved to Australia to work at the Sydney Institute for Astronomy, University of Sydney, on the SAMI Galaxy Survey.


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