ASTRON/JIVE Summer Student Programme 2013

Pete Gentile (USA)
My name is Pete Gentile and I am a graduate student at West Virginia University (WVU). At WVU, I study pulsars in the X-ray and radio regimes, and my work in the radio band continued this summer at ASTRON, where I wrote software designed to detect transient signals detected in the LOfar Tied-Array All-sky Survey (LOTAAS). Radio bursts of unknown, yet extragalactic origin have been discovered in higher frequency observations but not very much is known of these intriguing phenomena. Interestingly, these bursts have only been detected with the Parkes Radio Telescope, so simply detecting these bursts with LOFAR would be an accomplishment. At ASTRON, I wrote software to help detect these and other transient phenomena in the LOTAAS survey. Working at ASTRON is extremely interesting, as you are in close proximity to people that do very different work. At any time, you are a short walk away from someone who is reducing EVN data, testing a new receiver at extremely low temperatures, or writing software to help deal with LOFAR's extreme data output rate. You have the opportunity to talk to people with different backgrounds and interests on a daily basis over coffee, tea, or a game of bridge. And you're always only a short bike ride from Dwingeloo, where you can get chocolate fondue (with liquid Nitrogen!), or, if you're lucky, go to a town festival, which I found incredible since the town has a population of just over 2000. Or maybe you want to stay in the guesthouse, where you might eat spicy noodles cooked by Koreans, carbonara cooked by an Italian, or a good old-fashioned burger cooked by an American. And that's just the impromptu stuff! Soccer, game night, pancake parties, barbecues, even karaoke in ASTRON! (Thanks, Mike Garrett!) There's always something fun and interesting to do. I could go on and on, especially considering that I haven't even mentioned things you can do outside of Dwingeloo. Needless to say, the summer student program was a wonderful experience that I urge any student to consider.
Maria Grazia Blasi (Italy)
My name is Maria Grazia Blasi and I finished my Masters in Astrophysics at University of Bologna last year. In this summer project I worked at JIVE with Dr. Gabriele Surcis, Dr. Huib Jan van Langevelde and Dr. Ciriaco Goddi. For this project, I analyzed the 6.7 GHz methanol maser in an high mass star forming region called G213.70-12.6 (IRAS 06053-0622), which is only 830 pc from us. The goal of the project was to determine the orientation and to estimate the strength of the magnetic field on small scales in this region using the methanol maser. This is part of a larger project that uses the observations of several high mass star formation regions in order to do a statistical study that will provide more reliable information to use in simulations for a better understanding of the high mass star forming process. I used AIPS to reduce the 6.7 GHz observations, which were taken in November of 2012 using eight of the European VLBI Network (EVN) antennas. After I identified the 6.7 GHz methanol masers, I could analyze their properties, such as the circular or linear polarization, from which I could determine information on the magnetic field in the area. I really enjoyed the time spent in Dwingeloo from different point of view: the summer school gave me the opportunity to live a completely different experience. From an academic point of view I really enjoyed the topic of my project, which is quite new and it has been developing just recently which means I could learn more about something that I didn't study very much during my master’s degree. But I also enjoyed the Astrolunches and the lectures. During this twelve weeks the people in the institute also organized other activities, like soccer on Tuesdays, bridge on Wednesdays, several BBQs or the pancake parties. We also tried softball a couple of times, and we took part in "wadlopen", the walking in the mud for arriving to the island of Ameland. We also had the chance to visit the ESA center in Leiden, the Westerbork Synthesis Radio Telescope (WSRT), and the LOFAR core. The other aspect of this summer that I also really enjoyed was the opportunity to meet people from different countries and with different cultures, starting from the others summer students with which I spent most of the time. We also visited some cities near Dwingeloo during the weekends, like Amsterdam, Groningen, Assen and we had also the opportunity to see some festivals in Dwingeloo and in Lhee, the village very close to the guesthouse. I want to thank my supervisors, and also the people that took care of us during this summer in the guesthouse and in the ASTRON/JIVE institute.
Minju Lee (Japan)
Hi, my name is Minju Lee and I came from Japan, but originally from South Korea. I am studying in Japan and finished my undergrad study at Kagoshima University and I have just started my master's course moving to University of Tokyo. My project in ASTRON was to find new radio-loud lensing galaxy systems using mJIVE-20 project, and I worked with John McKean, Adam Deller and Javier Moldon. mJIVE-20 project is the largest 20 cm snapshot imaging survey using VLBA. We used new methodology to find radio-loud system in this project skipping the pre-selection observations(of using VLA and MERLIN) used in CLASS(The Cosmic Lens All-Sky Survey) work. There were a large amount of data sets obtained from the snapshot survey that I had to deal with. But with a great use of several filtering algorithms we developed and with a careful imaging process, I could find 5 "A-class" potential lensing system plus 9 "B/C-class" candidates out of 17700 sources targeted. The interesting was, two of the "A-class" sources were found out to be already known system. We got observation time for 3 three other "A-class" candidates as well as a proposal submitted for the rest of B/C sources with other frequencies to compare spectral indices, during the summer student programme. It was unfortunate that I could confirm none of the new lens system during the period, but we are quite convinced that we are about to find new lensing system with this new methodology. The summer programme is over but I will continue to contact with my supervisors and take part in this pilot project to find new lens system. Besides on the work of project, I enjoyed the life in Dwingeloo very much which includes many activities such as mountain biking, softball game, festivals and so on. Also, trip to 'Wadlopen'(Walking in the mud) was a highly impressive one for me because it was my first experience to walking in the mud, through waist-height sea water, and I'd like to do it again if I get a chance to come back here to work in ASTRON. We also had several lectures for radio astronomy, and visited ESTEC, LOFAR, WSRT. 12 weeks of summer student programme was a great opportunity for me who just started master's course, it gave me a new insight of how to do research and how to do work with other researchers. It was a great pleasure to have many chances to meet many researchers and talk with them. I definitely recommend you to get inside this summer student programme.
David Starkey (UK)
My name Is David Starkey. I have just completed my undergraduate masters degree at the university of Leicester. This summer, I worked with Ger de Bruyn, Vibor Jelic and Maaijke Mevius on identifying ionospheric effects in LOFAR polarisation studies, and investigated the spatial and temporal structure of the ionosphere. The LOFAR epoch of reionisation (EOR) project conducted 27 observations of the bright quasar 3C196 between November 2012 and March 2013. Performing RM synthesis on these observations in 1 hour intervals allowed me to identify 6 polarised sources in the 5 x 5 degree field. The peak faraday depth of these sources can be seen to drift over the 8 hour observation. This was compared to GPS data, confirming the ionosphere is responsible for these fluctuations. Applying this technique to all 26 of these observations will help us to use such polarised sources to correct ionospheric shifts in the faraday depth in future RM synthesis studies. I also investigated the spatial and temporal structure of the ionosphere over baselines up to 100km over the range of the observation period. I was able to discover a linearly increasing gradient in the fitted station TEC vs station latitude. This gradient is now in use as a constraint in the TEC fits, and I was able to use these TEC fits show that large scale ionospheric fluctuations occur over horizontal distances much greater than 100km (the largest baseline in the observation). Outside of the project, the summer student programme offers a plethora of social and educational activities. These included weekly lectures and lunch talks featuring guest speakers giving talks on their current fields of research. The topics ranged from Pulsars and the EOR through to updates on the status of the SKA project. The programme included trips to ESTEC, LOFAR and the Westerbork Synthesis Radio Telescope (WSRT), and the social side of ASTRON has given me the opportunity to meet many interesting and wonderful people. The weekends were full of incredible sightseeing opportunities including trips to Amsterdam and Groningen and I was also able to take part in the annual ‘Wadlopen’ trip - a 10km trek through mud, sand and sea water to the town of Ameland, just off the North Coast of the Netherlands. Working at ASTRON was a great privilege and I would jump at the chance to return again in future. I highly recommend the programme to all friendly and dedicated budding astronomers.
Anna Williams (USA)
Hi, my name is Anna Williams, and I am a 4th year PhD student in astronomy at the University of Wisconsin-Madison. I am interested in magnetic fields in galaxies, and how they affect the large-scale structure, energy balance, and star formation processes. One way of deducing the properties of magnetic fields is by observing the polarization of a source. Then, by looking at how the polarization properties change as a function of wavelength, we can learn about the ordered component of the magnetic field and internal structure of the medium it resides in. The work that I did at Astron as part of the 2013 Summer Student Program was an excellent complement to the work I am doing at my home institution in the United States. This summer I worked with George Heald to study the polarization properties and magnetic fields of NGC 6946. NGC 6946 is a nearby (5.5 Mpc), nearly face-on spiral galaxy with ongoing star formation. This galaxy has been the source of a wide variety of studies to better understand the properties of spiral galaxies such as star formation and gas content. Previous studies have also looked at its magnetic fields using radio observations between 3cm and 22cm, but with limited band-width at the shorter wavelengths. This summer was the first time broad-band, high spectral and spatial resolution observations were taken at 6cm and 13cm for this object. I calibrated and imaged the 13cm observations taken at the WSRT, and combined the data with previous 18cm and 22cm data taken for the WSRT SINGS survey. This data set allows us to study how the depolarization changes across the galaxy, and the interaction between the galaxy's magnetic fields and interstellar medium (ISM). Much to our surprise, the depolarization at 13cm was much greater than anticipated, making the calibration of the 6cm data a crucial next step in the project. We are now fitting models of various depolarization mechanisms to the data to better understand how the magnetic fields affect the turbulent ISM and star formation. This summer, I also made a map of the Faraday rotation measure across the galaxy using the 13cm, 18cm, and 22cm data. The Faraday rotation depends on the electron density and line of sight magnetic field. By increasing the wavelength range used to create the map, we see different features than was previously observed with only the 18cm and 22cm data. The new observations allow us to probe more extreme Faraday depths, and gain new insight to the line of sight magnetic fields in NGC 6946. My experience this summer has provided me with important research techniques, and a more in depth understanding of the astrophysical processes I am studying for my dissertation. It introduced me to ground-breaking researchers in the field, and helped me to build important contacts for my current and future research projects. In addition to a productive summer of science, I had a blast getting to know the other summer students and interacting with the welcoming staff and scientists outside of the institute! I'm very thankful for my opportunity to participate in the Astron/JIVE Summer Student program, and look forward to seeing everyone I met this summer at future conferences and workshops! It was great to meet you this summer! Hope to see you again in the not too distant future!

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