Department of Astrophysical Sciences
4 Ivy Lane
Princeton University
Princeton, NJ 08544
P.Schellart@princeton.edu
http://www.astro.ru.nl/~pschella
Ph.D. with experience in tera-scale data processing looking for an exa-scale challenge

Work experience

Scientific Software Developer Princeton University

Designing and developing core libraries for the data release production system of the Large Synoptic Survey Telescope (LLST). Collaborating with other members of the data management group in an Agile environment, constructing higher-level scientific pipeline code in C++ and Python.

Software Architect Radboud University Nijmegen

Coordinated software development efforts for the Radboud Radio Lab. Developed a real-time monitoring system with a web frontend and a Go + NoSQL (MongoDB) backend for VLBI observations with a global network of radio telescopes. Also developed a prototype database system with a KD-Tree index for n-dimensional inexact (i.e. nearest neighbour) searches in C++ with a BSON / JSON wire protocol.

Software Developer South African Astronomical Observatory

Implemented part of the data reduction pipeline for the slot mode of the SALTICAM photometer and the Berkeley Visible Imaging Tube instruments of the Southern African Large Telescope. Using Python, C, FORTRAN, IRAF/PyRAF and Qt.

Student Assistant Radboud University Nijmegen

Developed data acquisition and analysis software for a two-element radio interferometer in C, Python and LabView. Assisted in teaching a course on Radio Astronomy for freshmen and co-wrote the lecture notes for this course. Taught an introductory practicum on Radio Astronomy with distributed antenna arrays.

Education

Ph.D. in Science (Physics & Astronomy) Radboud University Nijmegen

Thesis: “Measuring radio emission from air showers with LOFAR”. Wrote a pipeline to identify and calibrate nanosecond timescale radio pulses in data from the worlds largest low frequency radio telescope. Performed statistical analysis on the resulting dataset to characterize the radio emission. Contributed to the achievement of a major breakthrough in the field: the first high-precision radio measurement of the air shower maximum. Found a link between cosmic ray radio emission and thunderstorms opening up a new field of interdisciplinary research.

Master Physics & Astronomy (cum laude) Radboud University Nijmegen

Thesis: “V348 Puppis”. Used non-equidistant sampling period analysis and Doppler mapping techniques on time resolved spectroscopic observations of a cataclysmic variable. Followed elective courses on numerical methods (integration, optimization, Monte Carlo simulations and neural networks) in addition to advanced courses on physics.

Skills

Programming

5+ years of experience with C, C++ and Python. Designed and implemented a pipeline in Python and C++, with OpenMP for parallel programming, to process many terabytes of timeseries data. Implemented an SQL database (PostgreSQL) backend and a web frontend for said pipeline. Wrote a C library with Python bindings for very fast coordinate matching of astronomical catalogs. Developed a real-time backend for a radio telescope, accepting data over a TCP or UDP socket and correlating it on the GPU using CUDA. Additional experience with many other programming languages.

For some examples of code I have written, see my github repository at: https://github.com/pschella.

Linux / UNIX

15+ years of experience with OSX and Linux on both desktops and servers. Managed the purchase, configuration, installation and operation of a still growing 45 node Linux based computer cluster with 0.5 PB of storage to handle all computational needs of the Nijmegen Astrophysics department.

Communication, collaboration and presentation

Experience with collaborative (open source) development. Contributed the lombscargle routine to SciPy and the cubehelix colormap to matplotlib. Taught several short courses on Python for scientists and wrote an introductory tutorial on the topic that is now used by many people in multiple universities. Presented talks at international and national conferences, seminars and workgroup meetings. Published multiple papers in high-impact peer reviewed journals (3 first author, 10+ co-author, several more in preparation).

Languages: Dutch (native), English (full professional proficiency), German (limited working proficiency).

Selected Publications

  • A large light-mass component of cosmic rays at 1017-1017.5 electronvolts from radio observations, Buitink, S., ..., Schellart, P., et al., LOFAR Collaboration, 2016, Nature, Volume 531, Issue 7592, pp. 70-73
  • Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers, Schellart, P., Trinh, T. N. G., et al., LOFAR Collaboration, 2015, Physical Review Letters, 114, 16
  • Polarized radio emission from extensive air showers measured with LOFAR, Schellart, P. et al., LOFAR Key Science Project Cosmic Rays, 2014, Journal of Cosmology and Astroparticle Physics, 10, 14
Full list of publications available online or upon request.

Personal Note

Outside of work I enjoy traveling & nature, seeing the world, meeting old friends and making new ones. In rock climbing and bouldering, both indoor and outdoor, is where I find the perfect combination of challenging myself and working together to solve problems.