Astronomy & Astrophysics Seminar: Ultra-cool White Dwarfs and an Automated Spectrophotometric Reduction Pipeline Builder
Marco Lam, TAU
Ultra-cool white dwarfs are among the oldest stellar remnants in the Universe. Their large gravity and low temperatures are responsible for the smooth spectra and the blue opacity due to collision induced absorption of the hydrogen molecules. For that reason, it is not possible to derive their radial velocities or to find thechemistry of the progenitors. The best that can be done is to infer such properties from associated sources, which they shared a coeval past. The simplest form of such a system is a common proper motion pair where one star is an evolved degenerate and the other a main sequence star. In this seminar I report the discovery of the first of such a system, the M dwarf LHS 6328 and the ultra-cool white dwarf PSO J1801+625, from the Pan-STARRS 1 3pi survey and the Gaia Data Release 2. This makes it the first and only benchmark of its kind to date. I will discuss the possible origins of this system.
In the second half, I will talk about a suite of publicly available spectral data reduction software to facilitate rapid scientific outcomes from time-domain observations. An automated pipeline frees astronomers from the performance of the routine data analysis tasks to concentrate on interpretation, planning future observations and communication with international collaborators. The project consists of two parts: the Wavelength calibration with RASCAL and the rest of the spectral calibration with ASPIRED. It is written in python 3, and was intentionally developed as a self-consistent reduction pipeline with its own diagnostics and error handling. It is intended for users to easily build their automated pipeline to reduce 2D spectral data to wavelength & flux calibrated 1D spectrum.
Seminar Organizer: Dr. Iair Arcavi