Summer student programme 2018

Summer student programme 2018

Anshu

Anshu

Hi, I am Anshu and I am a pre-final year PhD scholar at Indian Institute of Astrophysics, Bangalore, India, currently working in Solar Radio Astronomy at Gauribidanur Radio Observatory, India. This summer I worked with Dr. Pietro Zucca on simultaneous interferometric and tied array beam observations of the solar disk and the solar corona with LOFAR. I analysed the radio counterpart of solar flares, known as Type III radio bursts, which are a signature of propagating beams of non-thermal electrons in the solar atmosphere and the solar system. This radio burst was observed between 80-20 MHz, which corresponds to 1.4-4Rʘ on the solar corona. With high spectral and temporal resolution of LOFAR, we were able to track the propagation of the electron beam and spatially resolve the different trails of the type III bursts with time. We were also able to estimate the coronal magnetic field using this burst in the middle corona, using spectral-polarimetric data, which interestingly, is in good agreement with previous observations and results.

During my stay here, I relished every moment - the interactions with scientists and engineers at ASTRON/JIVE were really helpful, the small trips to Cologne, Brussels and Groningen with other summer students were fun. I really enjoyed the Bospub evenings & Wednesday games nights. The official visit to ESTEC, LOFAR core and WSRT were fantastic. The bike trips around the Dwingeloo Park, unofficial barbeques during Fridays evenings, the trip to Giethoorn are still fresh in my mind.

Finally, I would like to thank Pietro for the guidance and patience, Golam, Yogesh, Richard, Cees, Gemma, Sarrvesh, Maaike, Michiel, my fellow summer students, and all the people who made this summer program successful. I would love to visit ASTRON again!

Amy

 

Amy

Hi, my name is Amy and I have just completed my bachelor’s degree in Physics and Astrophysics at the University of Birmingham, UK. I had an incredible summer at ASTRON/JIVE, working with Cees and Tim in the Astronomy Group on a project titled ‘Finding Pulsars in the LOFAR Imaging Survey’.

The aim of my project was to define a set of selection criteria which could be used to discover new pulsars in the ongoing LOFAR Two-metre Sky Survey (LoTSS). Working with the LoTSS catalogue of 320,000 sources, I relied upon four typical pulsar properties to help distinguish them from other radio sources: point-like, a high fraction of polarised flux, steep radio spectra and a variation in source intensity caused by scintillation. I found six pulsar candidates which were followed-up by searching for pulsations using LOFAR. None of the sources were pulsars, but the search techniques explored in this proof of concept study could prove successful in finding pulsars in future LoTSS data releases.

With no prior experience in radio astronomy I was a little apprehensive about applying for the summer program, but I am so glad I did! It was really gratifying knowing I was one of the first to search for pulsars using LoTSS; the experience gave me a glimpse of what a research career would be like, something I aspire to. I wrote observing proposals and improved my computing skills immensely, vital for my upcoming Astrophysics masters.

Not only was it an invaluable academic opportunity, but I also have so many happy memories of my Dutch summer. On my first day, and every week from then on, I went for pancakes at the Bospub, we got to watch the total lunar eclipse over the heide, we visited Cologne and cycled so many kilometres we lost count! One weekend I got to moon bounce an image using the Dwingeloo Telescope; the image was transmitted to the moon, reflected from its surface and received back in Dwingeloo! Everyone I had the pleasure of meeting and working with was so welcoming, friendly and supportive. Thank you for making this summer so wonderful!

David

 

David

Hey, I’m David. I’m heading back into the last year of my undergraduate degree in Trinity College Dublin, Ireland, after spending the summer at ASTRON. I worked alongside Richard Fallows to study the phenomenon of interplanetary scintillation, where we observed a number of compact sources using LOFAR to see how their intensity varied on short timescales. Pushing LOFAR to it’s limits, we performed simultaneous beamformed and interferometric imaging observations at sub-tenth of a second sampling times on quasars 3C147 and 3C48 and used the imaging data as a basis for developing a pipeline for preparing the raw beamformed data to be processed and determine the fraction of the source intensity that varies in time. We can correlate that fraction, or ‘scintillation index’, to the density of the solar wind along the line of sight from free electron causing diffraction, giving rise to constructive and destructive interference. As a result, we expect that it should be possible to reconstruct the solar wind density with LOFAR through a tomographic reconstruction process after observing several sources, though this is currently untested.

Needless to say I’ve learnt a lot from my time at ASTRON, from working alongside some of the brightest minds in their fields, allowing you to often realise the authors of many of the papers you look into work inside the same building (easy to ask questions!), to the insightful lectures across the entire spectrum of radio astronomy (and colloquia that often diverge to shorter wavelengths) and problem solving alongside the other students in the visitor’s office (when you’re not being hit in the head with rubber bands), you have a huge range of opportunities to learn and improve your skills and abilities throughout your stay.

Outside of office hours, there’s more than enough to keep you busy. From the weekly Bospub trips and Mike’s games nights, to the trips we organised to Köln, Brussels, and surrounding towns, the LOFAR and Westerbork tours, the Oogstdag... There’s a lot of opportunities for unique and memorable experiences during your stay. And needless to say the Dutch countryside surrounding ASTRON is beautiful, clocking up over 1,000km cycling around the Dwingelderveld and surrounding Dutch countryside I only wish we had cycle lanes with surfaces as good as Dutch forest trails or country roads back in Dublin.

As I head back to start my final year project, I can’t help but thank Richard and everyone at ASTRON/JIVE for all their support and work throughout the summer to make the summer programme one of the best experiences of my life and hopefully giving me a strong foundation to start a career in research on.

Daysi

 

Daysi

My name is Daysi Quinatoa and I'm an undergraduate student at National Polytechnic School in Ecuador. My project was peering into the engines of massive star forming regions. I worked with Katharina Immer and Ross Burns. Although massive stars are extremely important in the chemical evolution of the galaxy and in the physics of the interstellar medium, its formation process and the role of the magnetic field are not well understood. By studying the magnetic field near massive young stellar objects we could know the role of the magnetic field in launching mechanism of the bipolar outflows. The Extended Green Objects(EGOs) are approximately 300 star forming regions displaying bipolar outflows. Massive stars evolve rapidly in the order of hundreds of thousands of years, as a result massive star forming regions are rare and are found at great distances. Consequently, it is difficult to observe and measure the magnetic field. One technique that allow us to measure the magnetic field is the microwave amplification by stimulated emission of radiation (MASER). In this project we measured the magnetic field in the line of sight of EGO G45.47+0.05 by using EVN observations of 1.6 GHz Hydroxyl masers.

Thanks to ASTRON/JIVE summer programme I had an unique opportunity to do research in radio astronomy and to gain skill sets with lifelong value. Thanks to the most amazing advisors Katharina and Ross. My summer was joyful and educational. I’ve made great friends, visited amazing places, and explored Netherlands.

Iuliana

 

Iuliana

Hey! My name is Iuliana, I’m from Romania and I am an undergraduate student at the University of Manchester. This summer, I worked at ASTRON with Yogesh Maan, Golam Shaifullah and Benito Marcote on pulsar emission. An ongoing question in this research area is whether pulsars have some intrinsic 'off-pulse' emission, outside their main pulse region. While any such off-pulse emission would be too faint to detect directly, the interstellar medium (ISM) can help by acting as a lens. In the right conditions, the signal from a pulsar could show scintillation, or intensity fluctuations, due to the irregularities in the ISM as it propagates through. If the pulsar's magnetosphere is not resolved, and thus the pulsar looks like a point source, the off-pulse emission should show correlated intensity variations to the ones of the main-pulse. This is the basis of a new technique. My project meant implementing this as a software package in Python to find a limit to off-pulse emission from pulsars. This software could then be used with any pulsar observations and help a systematic search. During my project, I learned a lot from my supervisors and the people around. I also enjoyed working in the friendly environment at ASTRON.

On top of this, the trips we took, as well as the weekly Bospub dinner and games night, were so much fun! I could talk about them a lot, but I’ll just mention that we walked all the way to an island through mud, and we were near capsules that had been in space! Overall, this summer I’ve seen a lot of beautiful new places, impressive telescopes and met a lot of cool people, all while working on an interesting project and learning a lot about astrophysics research.

Alexander

Alexander

Hi, my name is Alexander and I'm one year into my PhD program at Astro Space Center in Moscow. This summer I worked with Zsolt, Benito and Aard from JIVE and Cees from ASTRON to study the only repeating fast radio burst and its environment.

Fast Radio Bursts is a phenomenon that produces brief (few millisecond duration) dispersed signals of unknown origin. Of the two dozens or so FRBs detected to date, only one of them showed repeated bursts, FRB121102. The source is located in the outskirts of a dwarf galaxy and has a faint, persistent radio source at the same location. This source is either a very peculiar, magnetar-powered nebula (with an unusually high radio power), or it is related to a low-luminosity AGN off-center in the dwarf galaxy.

The main goal of my summer project was to establish the properties of the persistent radio source using three epochs of EVN data at two frequencies. We studied its variability and found that its flux stays constant and location is very stable and does not depend on observing frequency. In this project we obtain the most accurate persistent source localization to date. We get an upper limit on its polarization, which is much lower than for the FRB itself. This proves beyond doubt that the persistent radio emission is not due to a large number of very weak repeating pulses. In addition the project included the study of the brightest pulse detected for this FRB at L-band. We got preliminary results on its polarization, which is much less than highly polarized C-band pulses. The detected rotation measure is the highest ever reported for this source.

Of course, a lot was happening during weekends and evenings after work. We had great trips to radio telescopes, space research center, nearby cities and even to walk through the mud all the way to an island in the sea. Thanks to my supervisors, JIVE, and ASTRON, this summer was both very useful and enjoyable for me!