Hi, Welcome to my webpage!
My name is Johanna, I am a Chilean currently living in Heidelberg, Germany.
I am PhD student at the Max Planck Institute for Astronomy (MPIA)
and a fellow of the International Max Planck Research School
Astronomy and Cosmic Physics at the University of Heidelberg (IMPRS-HD)
Orbits in action space with Gaia
During my PhD I am combining Gaia's awesome astrometry with spectroscopic information to explore how chemical abundances
of stars in the Milky Way (reflecting a common birth place/time) are related to their present-day orbits, and what it can teach us
about the formation of the Galaxy. In the Galactic disc this will tells us directly how strong radial migration was, i.e. if the
present-day orbit of a normal disc-star is related with its birth-orbit and address the fundamental question of how much
"dynamical/orbit memory" disc galaxies retain.
The image above is a voronoi plot with 100 stars per cell showing the angular momentum in the horizontal axis and the radial action (amount of in and out motion) of stars in our
Milky Way color coded by their metallicity. This dataset is a combination of Gaia's second data release and the spectroscopic survey LAMOST. The black star indicates the position of the sun in this plot.
Halo Wide Binaries
My MSc. thesis consisted on assembling an extensive catalogue of wide binary stars. This program was aimed to probe the wide
binary population of the Galactic halo at significantly large distances, and
inform future searches that could improve the statistics by orders of magnitude. These systems are very important because they can be used to place constraints on dark matter in the form of Massive Compact Halo Objects (MACHOs).
The image above is a Reduced Proper Motion (RPM) diagram constructed with data from the 9th Data Release of SDSS. The stars in this
plot have proper motions larger than 30 mas/yr. This diagram allows us to discriminate between disc and halo populations that are located to the right and left side of the confidence lines, respectively.