ASTRON/JIVE Summer Student Programme 2011


Mark Aartsen (Australia)

Hi, my name is Mark Aartsen, I have completed my undergraduate studies at the University of Adelaide in Australia and will be starting a PhD there in November. My project at ASTRON was to study the ionosphere, which has a large impact on imaging at the low frequencies observed by LOFAR. Working with supervisors Ilse van Bemmel, Ronald Nijboer, John McKean and Ger de Bruyn, I was able to show that LOFAR is able to accurately detect Traveling Ionospheric Disturbances (TIDs) which are wave-like structures which propagate through the ionosphere, and that we can solve for the differences in the ionosphere towards sources away from the phase center of our image.

The amount I have learned here is incredible, and working here and seeing the summer student lectures and weekly colloquiums has shown me just how interesting and diverse the field of radio astronomy can be. In addition to that was all the fantastic experiences here, from Wadloping to Wednesday Bridge Nights, as well as the adventures with all the summer students from seeing the Effelsberg telescope and the city of Cologne to having dutch pancakes for lunch at the nearby Bospub. It was an incredible time and I can't thank the people here at ASTRON/JIVE enough for the opportunity and kindness, and would like to thank the summer students as well for all the great times we had here.

Lars Floer (Germany)

My name is Lars Floer and I'm a PhD student at the Argelander-Institut für Astronomie which is part of the University of Bonn, Germany. In my thesis I work on the extragalactic data from the Effelsberg-Bonn-HI-Survey. This includes developing methods for radio frequency interference mitigation, source extraction, compilation of a source catalog and statistical analysis of it.

During my stay at ASTRON I worked mostly with Paolo Serra on source finding for HI surveys. I've developed a new source finding algorithm based on wavelet transformations and partial reconstruction of the data and evaluated the performance of the algorithm using various simulated datasets. In addition I also worked with Paolo on an source finder that uses negative detections to assign a probability of being a true source to each detection. Both projects gave me the opportunity to meet other people from the source finding community and I made valuable contacts with people working on ASKAP, the australian SKA pathfinder.

Furthermore we had many interesting lectures that gave a great overview of the work done at ASTRON/JIVE, took part in various excursion to the telescopes as well as non-astronomical sites. Together with the nice group of summer students, the excellent guesthouse (including the magically refilling fridge) and the overall pleasant working atmosphere, this was certainly one of my most productive and at the same time enjoyable summers. 

Claire Gilpin (USA)  

I came to ASTRON from Franklin & Marshall College, in Lancaster, PA, where I will be entering my senior undergraduate year in September.  This summer, I worked with members of the pulsar group, Jason Hessels, Joeri van Leeuwen, Vlad Kondratiev, and Anastasia Alexov, searching for fast transients and single pulse events with LOFAR. My main work at ASTRON was working to design a new survey with LOFAR LBA’s to target these events at low frequencies (20 MHz -30 MHz).  This survey now goes by its acronym, LoMASS, for LOFAR Meridian All-Sky Survey.  It is so named because the observing configuration is such that LOFAR stations form beams in an arc along the meridian (where the sensitivity is greatest).  I spent a large portion of my time developing code to generate a list of observational coordinates (the position of these coordinates depends on many factors including observing frequency and the length of each observation).

In addition to work, ASTRON also had a variety of different activities for the students to participate in, including bridge at the Noordam’s, soccer (football) on Tuesday afternoons and wadloping.  The summer students, as a group, also had many opportunities to take some wonderful weekend trips (to Amsterdam, Effelsberg, and Cologne).

Everyone at ASTRON was very welcoming.  I learned so much and had an amazing eleven weeks!  To those thinking of applying for future ASTRON/JIVE summer programs, don’t miss your potential opportunity to come work with the incredible scientists in Dwingeloo!

Ronan Murphy (Ireland)  

Hello, my name is Ronan Murphy, I am an undergrad at University College Cork in Ireland, I am just about to enter my final year.

For my summer school project I worked under the supervision of Mehreen Mahmud. My task was to reduce VLBA data from December 2008, which was an experiment to re-observe 7 AGN, at 4.6 – 43 GHz,  from a sample of >1 Jy BL Lac objects in the northern sky which showed interesting rotation measure (RM) gradient reversal patterns. I reduced the data, then made total intensity, polarization and rotation measure maps of the sources. The rotation measure is the degree to which the incident radio waves are rotated by due to the material of the AGN, with respect to wavelength. Part of my project was also to attempt to correct for core shift, which is the movement of the peak flux with respect to observing frequency. Once rotation measure maps were made, I looked for the presence of gradients and to see how, or not, they have changed over time. For 0716+714, we found that the gradients present above and below the core were consistent with the gradients in the 2004 epoch for this source. For 1803+784, we found that the rotation measure map tends to vary a lot for this source, possibly due to activity in the core, we were unable to confirm the presence of a gradient at the previously observed location, but using the previous maps, it is clear that this source is very variable.

I spent 11 weeks at ASTRON/JIVE this summer, and it was one of the best summers I’ve ever had, despite the weather which seemed to be constantly raining. We managed to organise a trip to Cologne for ourselves, a very nice city, and saw the Effelsburg dish as well. We also saw the LOFAR site in Exloo, which is actually a lot more exciting than initially thought by any of us. The national forest park, where the facility is based, is one of the nicest places I have ever been, it was quite enjoyable to go for cycle rides around the place, and also to go for pancakes every Sunday at the Bospub. I will also miss Bridge on Wednesday, but I will never forget how to play it. Wadloping is quite an enjoyable experience and I would highly recommend it to anyone. I will also miss the food, and the cooking schedule, which allowed us to enjoy some very nice meals, and to only have to cook about once a week. I also got to know several people around ASTRON/JIVE, whom I will never forget. And lastly, for a very enjoyable experience here, I’d like to thank all the summer students, my supervisor and all the people at ASTRON/JIVE!!  

Dyas Utomo (Indonesia) 

Hi, I am coming from Indonesia, where I did undergraduate study in astronomy at Institut Teknologi Bandung. This summer, I worked with Raymond Oonk and Raffaella Morganti to search for atomic hydrogen gas (HI) in six galactic clusters core. These six clusters are compact radio source selected from X-ray catalog to maximize the possibility of HI detections. While HI detections on those objects will double the current detected HI in galaxy clusters, non-detections will also useful to constrain upper limit of HI contents. This work is very important to give deep insight into the cool gas component as a result of cooling flow mechanism and to understand the role of AGN feedback in BCGs.

From six clusters, we successfully detect four clusters (A1795, RXCJ1850+68, RXCJ1350+09, and Zw 8193) with HI in absorptions against BCG and one cluster (NGC 4104) with HI emissions in front of BCG companion galaxy which provide evidence of cannibalism. All data are taken from the Westerbork Synthesis Radio Telescope and reduced using CASA.

Out of the research, I have plenty of good time here in ASTRON. I really love to play football and enjoy the bridge game at the evening. We also arrange dinner together for all summer students, and took nice trip to Amsterdam and Koln. Thanks for ASTRON and summer students for the happiness and joyful experience! 

Dijana Vrbanec (Croatia)

I study physics on University of Zagreb, Croatia. Although I've been in astronomy for some years now, this was my first project in the radio astronomy. I was working on simulations of the Galactic emission towards Abell 2255, under supervision of Vibor Jelic. The main motivation of our project was a study of Galactic emission, a major foreground component in the cosmological 21 cm experiments. We were simulating three structures of Galactic emission, observed in polarized intensity at 350MHz by Westerbork Radio Synthesis Telescope. 

I had a really nice time working on a summer project at ASTRON this summer. The project was very interesting, and since I am new in radio astronomy, I've learned a lot about radio astronomy and Galactic emission. We also had enough free time to explore the Netherlands and it costumes, e.g. mudwalking. We also had a very nice time during common  summer students dinners, which became our daily ritual. All people on the institute were very friendly and made us feel very welcome. Thank you ASTRON for a wonderful summer! It was a pleasure to meet and to know you all! :)

Fang Wu (China)

My name is Fang WU, a master student in Shanghai Astronomical Ob- servatory, P.R. China. My major interest is VLBI studies on Compact Sym- metric Objects (a class of young radio sources).

I work on an interesting broad absorption line quasar PG 1700+518 this summer under the supervision of Dr. Jun Yang and Zsolt Paragi. With the EVN and VLA observations, we identified its radio core and found that its jet is unlikely beaming toward us, consisting with the assumption of a large viewing angle in the rotating wind model. We also noticed that the jet may have a certain impact on the star-forming in its host galaxy.

It is an unforgettable experience in Dwingeloo. Beside working, I visited LOFAR center, WSRT, and Effelsberg, went outing by bike, and traveled to some nice places by train in the Netherlands. I will certainly miss the summer students garden party and Wadlopen. What’s more, I enjoyed every dinner cooked by other summer students in the guest house. This summer is really wonderful.

Sarolta Zahorecz (Hungary) 

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