Author Archives: ashna

Exoplanet Hunting using Gravitational Microlensing – Academic Poster

Creating an academic poster is a challenge because you never quite have enough space on your canvas to say all you want to say about your research. You have to be extremely selective and ruthless about the content that makes it to the final copy. This is what I found most challenging about making an academic poster.

I submitted a poster to the Faculty of Science Postgraduate Poster Competition recently. It came out to be in the top 20 and has been entered to the Exposure Poster competition. If you didn’t get a chance to stroll down to the basement of our office building to check out the many posters displayed there last week, here is my poster about my research. Hope you enjoy reading it!

Exoplanet_Hunting

MJUO 50th Anniversary Symposium

As Dr. Rattenbury has already mentioned in a previous post, the golden anniversary of the Mount John University Observatory (MJUO) was celebrated this year. I was fortunate to have been given the opportunity to attend and absorb the individual experiences of the astronomers.

The symposium’s theme centered around the observatory’s past, present and future. What I found most charming were the many stories told by astronomers who have become part of its history and who have had MJUO become an important part in their own lives in return.

Many times it felt like I was being transported to a cozy chair by a fireplace with grandpa recollecting the fascinating stories of his life, the adventures he had as an astronomer.

Here are only some of the many interesting things I heard during the symposium.

Audrey Walsh reflected upon her father, Frank Bateson’s work in establishing MJUO. Frank Bateson is the father of NZ astronomy, is has been said. In his own words, he was a “businessman by profession, astronomer by nature”. Hearing these words was an extremely inspiring moment for me, for it brings to my mind the image of a man who was passionate about his work.

Ed Guinan gave an entertaining account of the adventures and misadventures he had during the year he spent at MJUO and NZ in general. It was disheartening to hear that a chart of his results, which he kept close to him instead of shipping it, out of fear of losing it, was after all lost to the USSR customs while travelling through Russia.

The talk given by Alan Thomas painted a vivid picture of the contrast between observational astronomy as it was done all those years ago and how it is done now. Part of the excitement then was enduring the cold of the nights, snuggled up against a telescope in the open, in a sleeping bag, with a hot beverage, looking through the eye-piece.

Graeme Kershaw’s talk highlighted the fact that many countries have lost contact with the night sky so that lots of people come to lake Tekapo just to see the stars. He also pointed out the growing frustration of the elderly who grew up gazing up at the stars but can not offer the same to their children.

Many other talks painted similar pictures and drove it home that MJUO is one of the world’s most beautiful and easily accessible telescopes, rich with history and memories of individuals.

I have come out from this celebration with a refreshed aspiration for astronomy!

PhD update

An important part of provisional year of PhD candidacy is to refine one’s research question.

While I wrote an evolutionary algorithm code as an optimization method to search the high dimensional parameter space of the microlensing modelling problem, I have been faced with the tough decision to place it on the sideburner while diving into a new area of investigation for the purpose of refining the research question further.

This was due to the literature findings that suggest that microlensing model comparison techniques are in need of development, beyond the comparison of chi-square values alone!

This new direction of investigation involves Nested-sampling based algorithms for simultaneous parameter estimation and model comparison, based on the Bayesian approach.

PhD candidate–Ashna Sharan

Hello there. I am a PhD candidate investigating the use of GPUs in modelling planetary microlensing events, as Nicholas Rattenbury mentioned in his  recent post. We have on hand a GPU-based code for modelling and simulating gravitational microlensing events. The immediate goal of my project is to use the GPU-based code to model real microlensing events and searching for extra-solar planets. Future work could potentially involve introducing concepts of Swarm Intelligence to optimize the parameter search strategy in finding the best-fit model.

On another note, I completed my MSc in Mathematics at the University of the South Pacific, Fiji, having a Mathematics and Physics background at the undergraduate level. I have always been interested in Astronomy and find myself fortunate that Department of Physics, University of Auckland gave me the opportunity to pursue  it! I expect a challenging yet exciting ride ahead of me, as I journey through my PhD candidacy!