Tag Archives: hubble

Hubble Fellows Symposium 2016


It was great to visit Baltimore one last time and see the other fellows again. Baltimore has become a major hub for astronomy, even more so since STScI started hiring for JWST and WFIRST. All my friends from Yale seem to live in Baltimore now!


Hubble Fellows Symposium 2015

2015 Hubble_Fellows_Symposium_GroupPhoto 2

Right after getting back from Chile I headed straight to Baltimore for this year’s Hubble Fellows Symposium at the Space Telescope Science Institute. Every year most of the 51 Hubble fellows (three years with each 17 fellows) get together at these meetings to present their work to each other. It is quite a fun meeting, since you get exciting updates on nearly all major fields of astronomy within three days. Last year we criticized, though, that the schedule left no time for chatting, schmoozing and collaborating. This year the organizers relaxed the schedule  a bit, so every talk was only 20 minutes long. It made the meeting much more enjoyable and put the fun back into the symposium.

Mass segregation in Palomar 14

The mass function slope is shown as it changes with radius of Palomar 14 (measured from the cluster center). A low value of this slope means that we detect more massive stars at this radius than further out, where the slope is larger. Such a signature is called mass segregation, and is usually a consequence of dynamical evolution of a star cluster.

Matthias Frank, Eva Grebel (both in Heidelberg), and I have recently published another paper on one of our Milky Way’s outer-halo globular clusters. Using archival data from the Hubble Space Telescope and Matthias’ sophisticated photometry tools, we measured the masses of stars within one of the most controversial globular clusters known to us: Palomar 14.  Continue reading Mass segregation in Palomar 14

Hubble TAC


In the first week of June, I went once more to Charm City Baltimore to attend the Hubble Space Telescope Time Allocation Committee meeting. This exclusive event takes place once a year at the Space Telescope Science Institute (STScI), and is meant to sort the wheat from the chaff among the many, many applications for observing time on the Hubble Space Telescope (HST).  Continue reading Hubble TAC

Palomar 4

This website was never intended to be a science blog, but since science is an essential part of my life – with all its ups and downs, kinks and quirks, bores and funzies – I shouldn’t neglect it here! Today, a paper of me and my dear collaborators from Iran, Elham Hasani Zonoozi and Hosein Haghi appeared on astro-ph.

Mass function slope versus cluster radius
Slope of the stellar mass function versus projected radius from the cluster center for the observations of Palomar 4 (red) and for our best-fitting model (black). The goal was to find a model that reproduces the observed trend of the massive cluster stars being more centrally concentrated, which can be seen from the slope being below its nominal value (dashed line) in the center, while being above that line in the outer parts of the cluster.

Continue reading Palomar 4

Johns Hopkins


Last night I arrived in Baltimore, Maryland, which PR agents in the 70’s tried to dub as Charm City. Anyone who has seen The Wire knows that this is nothing but a bold face lie. Nevertheless, I’ve enjoyed a nice and sunny Sunday walking across the campus of Johns Hopkins University, through some sketchy neighborhoods of Baltimore, all the way down to the nicer and more gentrified parts of town. I must admit, Baltimore got its charm. Especially the independent coffee shops far off the touristy parts around the Inner Harbor area appealed to me. The next few days will give me some more time to make up my mind about this city: the 2014 Hubble Fellows Symposium is being hosted by the Space Telescope Science Institute until Wednesday. Almost all of the about 50 current Hubble Fellows are getting together to enjoy each other’s science and company. A first trip to a local bar with my former Yale colleagues Rachel Bezanson and Erik Tollerud started off sciency with a discussion of the premier of the new COSMOS earlier this evening, but ended up in watching the finale of True Detective on HBO, and talking over drinks with random townsfolk. Quite a day.