Sometimes a simple hobby propelled by the humble Binocular could lead to a never ending quest to explore unknown frontiers, with the opportunity to work on the next generation ground-based gamma-ray instrument, The Cherenkov telescope array (CTA).

Pooja Sharma, our next pathbreaker, Astroparticle Physicist,studies the high energy physics governing supernova remnants (SNRs) and simulating their spectra as seen by CTA.         

Pooja talks to Shyam Krishnamurthy from The Interview Portal about the awe inspiring experience of spending 3 nights at the Observatoire de Haute-Provence (OHP) where the first exo-planet was discovered, and cherishing the experience of night long observations.

For students, you are always told to push the boundaries. But what if there are no boundaries to the universe that we are a part of? Take it on to yourself to find out more. Read on …

Pooja, tell us about your background?

I am the daughter of ordinary parents when it comes to academics, but extraordinary human beings when it comes to values. I have been quite a rebellious child who has always wanted things her way, but my parents have strived to give me and my sisters the best of everything. They taught me to be self-sufficient, loving and most importantly, respectful towards others. The most important gift they gave me was the freedom to study whatever I wanted. Excellence was never demanded; I was only asked to put my best foot forward. 

I moved around quite a bit during my childhood. As a result, I got a chance to start over every time, each time trying hard to set new goals to be achieved, and become a better version of myself.

My education has been a Mélange of various styles – CBSE, IGCSE, IB and UGC, each having its own set of pros and cons. 

By the time I had completed my high school, I had managed to explore various domains in Science and Arts as choosing a stream was not compulsory. This proved to be quite important as I got enough exposure in different fields to truly understand which one, I preferred the most.

Before I started my college, I was torn between my love for English Literature and my undying interest in Astrophysics.  I chose the latter because I knew that I would make time for reading novels or writing poetry despite studying physics, but the reverse would not be a possibility.

I cannot stress the importance of a good balance. Not only between personal and professional life but always curricular and extra-curriculars. I have been quite active in community service, school and college fests and various competitions such as Model United Nation and much more. I liked nothing more than connecting with like-minded individuals and being part of events which are bigger than myself. I have always found planning events and watching them turn into a reality, quite exhilarating. During my college years,  I had also started an Astrophysics club, which helped me keep my interest alive and also allowed others to explore its wonders. 

What did you do for graduation/post graduation?

I did a B.Sc. in Physics from Amity University. One of the most interesting parts of the curriculum at university was a compulsory internship, which turned out to be the first stepping stone of my career in astrophysics.  

I interned under Prof. S.N.A. Jafferry in Udaipur for a month. He was a retired researcher from IUCAA. Together, we explored the physics behind x-ray binaries and Gamma Ray Bursts. With him, I learned to analyze data and write a research paper. This study was continued under guidance of Prof. Suresh Chandra, Deputy Director at Amity Centre for Astronomy and Astrophysics. 

Soon after my graduation, through the help of my senior, Mr. Debdibta Biswas, I applied to University Paris Sud (9th in the world for physics and 1st for mathematics) for a MSc in General Physics. 

At first, I was discouraged from applying for institutions abroad, since they cost an arm and leg, but also because my parents had always been very protective of me, especially since I was a girl. 

Slowly things fell into place, first when my father agreed and decided to apply for a loan and second when I managed to get full funding for my masters by TATA TRUSTS. With no need for a debt and an admission to one of the best Universities, there was no stopping me. 

I pursued my doctoral studies (PhD) from University Paris-Saclay (ranked 9th in the world for physics and 1st in Europe). My thesis involves simulating SEDs of Supernova Remnants and understanding the physics behind it. 

What made you choose such an offbeat, unconventional and fascinating career?

I had always been interested in Astrophysics, whether it was roaming around with my mini telescope or binoculars for stargazing as a child or just reading books. It really wasn’t just because of a particular individual, rather it was the mysterious dark universe, diamond like stars that encapsulated my interest. 

It’s probably worth recounting the numerous blessings of my Parents, Nana ji and Nani ji, who have always encouraged me to dream bigger no matter what cost and always ensured that all my needs are met. My extended family was always there to remind me that  I have people who love me and are rooting for me, for better or for worse.

I have been blessed by a wonderful family and few close friends who have always encouraged me to march forward. 

I am thankful to all my professors who have sparked my interest and kept the flame of interest glowing in me. 

My journey since receiving the TATA TRUSTS gift scholarship and getting admitted into great colleges has been quite unfathomable. I still look back in utter disbelief and thank fate for opening such opportunities for me. 

I went to their portal and applied by sending them a statement of purpose, letter of recommendation etc. Then I got shortlisted for an interview with head of TATA TRUSTS and a subject expert from IUCAA. I was soon awarded a generous gift scholarship of Rs. 8 lakhs.  I will always be grateful for their help when I needed it the most. This is one of the major reason, why I wish to come back to India and pay their favor forward. 

I have come to understand that indeed, there are various events which will not make sense at a point. However, when you look back, everything falls into place; the dots connect

How did you plan the steps to get into the career you wanted? Or how did you make a transition to a new career? Tell us about your career path

Although I knew that I wanted to become an Astrophysicist, I was quite confused, because there was no clear path. 

I researched mostly by myself and asked all the people I could talk to for their opinions. 

Transitioning from international board in high school to UGC in college and again to a French board in master’s has indeed been quite a difficult journey. Each time, there were things I was expected to know and hence had to struggle outside academic hours to be able to match the pace of others. 

Instrumental in starting my journey in the field of research was my mentor Prof. S.N.A. Jaaffrey with whom I did an internship during my bachelor’s degree. He not only taught me how to analyze data of Gamma Ray Bursts (GRB) and X-ray binaries from NASA’s swift satellite using HEAsarc archives, but also taught me to think out of the box which led us to discover the possibilities of a GRB to hold the answers to the beginning of the universe. This work was further guided by Prof. Suresh Chandra, who has always shown great support for my career.

In Paris, as a part of my first year of Master program, I gained first-hand research experience at one of the finest organisations in France – The French Alternative Energies and Atomic Energy Commission or CEA. I worked under Dr. Thierry Stolarczyk who is the leader of the Cherenkov Telescope Array (CTA) team. I studied how CTA can be used as a probe to study the attenuation of gamma rays from GRBs due to the extragalactic background light (EBL). It was quite difficult as I had to delve into heavy literature review and learn python programming with little help.

For my second year of masters, I shifted to Aix-Marseille University and did all my projects in Laboratoire D’astrophysique De Marseille (LAM). LAM had a quite research-intensive environment with friendly researchers from various fields in astrophysics and astronomy. 

My first project was under Dr. Denis Burgarella, on Stellar Evolution Exploration of Planetary Systems in 3D. In it I used models from Geneva grids of stellar models using which I studied the evolution of different stars depending on their initial stellar mass, over cosmic times. Using Vpython I also simulated a planetary system orbiting around a central star and studied how the temporal evolution of the main physical parameters of this star affected planets near it.

For my second year internship, I interned under Dr. Dennis Burgarella and Didier Fraix-Burnet where I deftly varied the input ingredients of CIGALE (Software to build Spectral Energy Distribution SEDs of galaxies) such as Initial Mass Function, dust attenuation etc to create a large  sample of synthetic spectra of galaxies. Then a machine learning tool, FisherEM algorithm was used to find a robust classification of these spectra. This has greatly enhanced my knowledge in the domain of galaxies and a bit of machine learning. This internship made me realize the wealth of information that we can extract from any SED of an astrophysical source.

Finally, after passing the Ecole Doctoral interview, I got funding from PHENIICS to pursue my doctoral studies from University Paris-Saclay (ranked 9th in the world for physics and 1st in Europe). My thesis involves simulating SEDs of Supernova Remnants and understanding the physics behind it. I am also calibrating the camera for the Medium sized telescope in the CTA array. 

There is no strict approach to finding an internship or getting selected for a PhD. They both involve writing a lot of emails to people and it helps if you have good networking skills. 

In the domain of astrophysics, it is now simply not enough to have a theoretical background in the subject. One also needs to develop a fluency in coding, excellent analytical skills and an independent mind set.  

There are various organizations which fund students and it always helps to keep a list of them with the deadlines. Some popular ones are, Eiffel Scholarship, Charpak Scholarship, L’Oréal scholarship and various Ecole Doctorale and regional funding programs (specifically for France).

It does help to get a PhD or an internship if you know the supervisor before- hand and if they know of your ability to work independently and effectively. 

Hard-work and determination trumps luck, always.

What were the challenges? How did you address them?

Challenge 1: Gender Bias –  I distinctly remember one of my experience in Udaipur, where I was considered as a girl of low character because I decided to stay out in a college till hours for observations. It is sad, that girls in India, till date don’t feel safe and respected. Few of my own family members have looked down upon mom and dad, for having 3 girls. With my twin sister, a Junior Research Fellow at AIIMS in the department of Neuropsychology I am glad that we have proven that women are not a burden when educated well.

Challenge 2: Learning how to code from scratch – You should be an expert in at least one of the coding languages. For me, it was mostly self-taught with the aid of various video lectures, googling and experienced friends. Learning is always an ongoing process, especially with the rate of current advancements in AI and technology, this struggle will only increase.

Challenge 3:  Toxic Work Environment – There may be times when you may not get an encouraging supervisor, or some difficulty arises in assimilating with the lab members because of shyness or language barrier. Keeping in mind the bigger picture of what you want to achieve helps in getting through the bad days. You may also vent out to your closest friends to gain respite. However, nothing is worth disturbing your mental peace and if it continues for a long duration, best is to leave and find a happier place. 

Challenge 4: Loneliness: Although one may have millions of friends, it is quite easy to feel displaced in another community devoid of any genuine relationship. To have a more pleasant stay, it is important to indulge in an activity which soothes you and keeps you occupied. It is important to stay in touch with those close to you and remembering the gratitude you owe for the things you already have.

Can you tell us about your current research?

I work at IJC Labs, in the A2C department (Astroparticles, Astrophysics and Cosmology) in Paris. 

My thesis is divided into two parts:

  1. Under the guidance of Prof. Tiina Suomijarvi,the first part of my thesis deals with studying the high energy physics governing the supernova remnants (SNRs) and simulating spectra of SNRs as will be seen by CTA.                                                                                  

The Cherenkov Telescope Array (CTA) is the next-generation worldwide gamma-ray astronomy facility. The CTA Observatory is composed of the large- (23m diameter, LST), medium- (12m diameter, MST), and small-size (4m diameter, SST) Cherenkov telescope arrays that will be located in La Palma, Canary Islands, and on the ESO site in Paranal, Chile. With its unprecedented sensitivity, its arcminute angular resolution, an excellent energy resolution, and a wide energy coverage from 30 GeV to 300 TeV, CTA promises a major leap forward in our understanding of cosmic accelerators.  More information on CTA can be found at and Science with the Cherenkov Telescope Array, The Cherenkov Telescope Array Consortium, arXiv:1709.07997 [astro-ph.IM]. 

2) The second part of my thesis is under my co-supervisor Dr. Guilia Hull. I am involved in calibrating the camera of the MST of CTA.

What skills are needed for your job? How did you acquire the skills?

One cannot prepare oneself enough for any PhD. It requires you to take on new challenges and find solutions to your problems, one by one. I find that apart from a good command over at least one of the programming languages, it is also necessary to have great analytical and research skills. These can only be acquired via hands-on experience. You should be ready to do a lot of self-learning by reading various research papers, books and online lectures. Without doubt, one should have a certain discipline and motivation to get past all the lows and highs of the PhD life. 

What is a typical day like?

Sitting in an office – coding or reading papers and at other times experimenting in the lab. Just like many others, there are days when I feel that I have found my ikigai and then there are also some low moments when I question my choices. But overall, the lows are worth the highs. Spending quality time at lunch breaks and coffee breaks with my supervisor and colleagues is also quite an integral part of my PhD life. 

What is it you love about this job? 

I love the fact that I never know what to expect. Every day you can take up a new challenge. The joy of completing a task gives me satisfaction that no other job can give me. I love that I am being paid for learning and contributing to the scientific culture of the world.

 How does your work benefit society? 

I am a part of the CTA project, which is the largest ground based Cherenkov telescope array in the world. CTA’s accuracy, sensitivity, rapid slewing rate and wide energy coverage promises to address some of the most perplexing questions in astrophysics. I hope to be able to contribute to the successful functioning of the calibration system of MSTs and adding to the pre-existing knowledge of SNRs.

Tell us an example of a specific memorable work you did that is very close to you!

During the second year of masters, we were taken to Observatoire de Haute-Provence (OHP). This is the very same observatory where the first exo-planet was discovered. We spent 3 nights there, learning how to move the telescope to the desired coordinates, basics of image cleaning, asteroid tracking, spectroscopy and much more. Right from the thunderous sound of the humongous dome opening towards the cold beautiful sky to the night long observations, everything was mind-blowing. I remember the words of my teacher, Dr. Christophe Adami –“If you want a career that pays well, or if you want to do something quickly in life, then this field is not for you.” Despite years of experience, there is always going to something more that you need to learn and there will always be something more to achieve. In the end you won’t be rich with money but surely be rich in knowledge.

Your advice to students based on your experience?

With the right blend of determination, hard work and passion, you can achieve whatever you set your heart upon. Do not give up on your passions. 

Future Plans?

I have always been someone who planned for several years. I had a career plan, sorted from a very young age up to my PhD. However, right now, I am just letting the knowledge seep in and allowing myself to be swayed in the direction of whatever excites me the most.