Brandon Rajkumar
I am a Prize Scholarship recipient, pursuing a PhD in Physics with a focus on stellar variability mitigation as part of the Astronomy and Astrophysics group at the University of Warwick since October 2024. Supervised by Dr. Heather Cegla, I am working with the HARPS-N and HARPS3 (Terra Hunting Experiment) research collaborations to help mitigate stellar variability in radial velocity searches for low-mass, long-period planets around sun-like stars. Learn more about me and my journey from Trinidad and Tobago to the University of Warwick on my websiteLink opens in a new window.
Current Research
ExTEMPO - Exposure Time Evaluation for Mitigation of P-mode Oscillations
ExTEMPO is a tool designed for the Extreme Precision Radial Velocity (EPRV) community to optimise their observing strategy by considering the contributions of stellar pressure mode (P-mode) signals in their observations. It uses stellar parameters to estimate the RV signal due to P-mode oscillations at different exposure times for F, G and K-type (solar-like) stars. It is currently available for use on GitHub - https://github.com/BRajkumar041992/ExTEMPO
Past Research
MSc in Physics - Curriculum Erasmus Mundus Master's in Astrophysics and Space Science (MASS)
As an ERASMUS+ Scholar in the joint MASS program, my thesis explored the influences of stellar activity on radial velocity (RV) signals using the Sun as a proxy for sun-like stars. Relationships between RV measurements and stellar activity of sun-like stars were suggested by comparing sun-as-a-star RV measurements from the HARPS-N spectrograph to variations in stellar activity indicators measured for the Sun.
As part of the MASS program, I also carried out an internship at Côte d'Azur University, which focused on understanding time-series analysis techniques such as detrending methods and periodogram analysis applied to RV data. I was also able to make a small contribution to Sulis et.al (2024) “A low-mass sub-Neptune planet transiting the bright active star HD 73344Link opens in a new window”.
MPhil in Physics - Specialising in Solar Astronomy (Awarded High Commendation)
My MPhil degree involved the use of solar data obtained from the SDO, SOHO, and the UCCI Dr. Wm Hrudey Observatory, located in the Cayman Islands. Using tools like ImageJ, I analysed the fractal dimensions of active regions using white light data as well as magnetograms to understand the complexity within the umbral and penumbral regions. (Below is a summary poster of my MPhil.) This research produced two publications
- “A Fractal Analysis of Magnetograms Within Active RegionsLink opens in a new window” Solar Physics 295 (2):10 published in 2020, and
- “Fractal Dimensions of Umbral and Penumbral Regions of SunspotsLink opens in a new window” Solar Physics 292 published in 2017
Contact details:
Brandon Rajkumar,E -Mail: Brandon.Rajkumar (at) warwick.ac.uk
- LinkedInLink opens in a new window
- OrcIDLink opens in a new window
- ResearchGateLink opens in a new window
- GitHub
BSc General (Physics and the St. Augustine/Tourla (SATU) Observatory
The final year project of my undergraduate degree involved refurbishing a 16” Meade LX200 mounted on a Paramount ME II, located at the SATU Observatory in Trinidad and Tobago. The objective was to perform photometry on the comet 67P/Churyumov–Gerasimenko as it emerged from behind the sun. After overcoming several challenges, the project was successful, and I was able to contribute photometric data to “The 67P/Churyumov–Gerasimenko observation campaign in support of the Rosetta missionLink opens in a new window” Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375 (2097):20160249 published in 2017.
After completing my undergrad, I began volunteering at the observatory. The SATU observatory was established at the UWI, STA in collaboration with the Tuorla Observatory of the University of Turku, Finland. Its prime objective is an ongoing collaborative effort to monitor the blazar OJ287 located in Cancer.
While volunteering at the observatory and collaborating with researchers at the University of Turku, I was able to develop skills such as preparing and carrying out observations, collecting and processing astronomical data with a CCD, and performing photometry using AstroImageJ. These skills have allowed me to contribute meaningful data to the following publications:
- “Stochastic modeling of multiwavelength variability of the classical BL Lac object OJ 287 on timescales ranging from decades to hoursLink opens in a new window” The Astrophysical Journal 863 (2):175 published in 2018, and
- “Polarization and spectral energy distribution in OJ 287 during the 2016/17 outburstsLink opens in a new window” Galaxies 5 (4):83 published in 2017.
