Akshara Viswanathan
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astroakshara.bsky.social
Akshara Viswanathan
@astroakshara.bsky.social
PhD researcher in Kapteyn Institute, Groningen, NL|
Observational astronomer investigating baby Milky Way's shenanigan |🇮🇳🇨🇦🇬🇧🇳🇱|
she/her | தமிழச்சி
It's also probably a good time to say that I will continue doing Galactic archaeology as a Canadian Institute for Theoretical Astrophysics (CITA) National Fellow in University of Victoria, Canada.
www.cita.utoronto.ca/cita-welcome...
CITA welcomes six Fellows to cohort 2024 - Canadian Institute for Theoretical Astrophysics
CITA extends a warm welcome to our incoming Fellows and National Fellows. In September, we will be joined by four Fellows at our flagship at the University…
www.cita.utoronto.ca
January 2, 2025 at 4:52 PM
Thanks to my amazing co-authors @tada-matsuno.bsky.social @nfmartin1980.bsky.social @ankeaa.bsky.social and non-bluesky people - Else, Kim, Nicolas L., Raymond, Sebastien, Georges, Zhen, Martin, Federico.
Let me also take this chance to say that I'm on the postdoc market this fall. :)
September 19, 2023 at 3:27 PM
You can grab the catalogue here: astroakshara.github.io/rvs-paper/Ga...
75% of these stars have either no/not reliable metallicity value in literature. This catalogue is also ideal to study the properties of VMP stars in different parts of our Galaxy. PS few VMPs are visible to the naked eye!
astroakshara.github.io
September 19, 2023 at 3:23 PM
Now we have a catalogue of 1000 VMP stars all-sky that are so bright (G<13) ideal for high-res follow-up. This increases literature estimates by a factor of 3. It is incredible that I got to learn the power of archival data from big surveys to do science useful for the community
September 19, 2023 at 3:23 PM
We also compare our metallicities to other works that analyse RVS spectra like the amazing GSP-Spec pipeline by the Gaia consortium and improvement in the VMP end by Matsuno+ 22. We have good agreement if used with their quality cuts, but this is only a small overlap (~25%)
September 19, 2023 at 3:22 PM
We validate our inferred metallicities with existing spectroscopic surveys (APOGEE and GALAH) and dedicated high-resolution follow-up of VMP stars to learn the purity and precision of our analysis. Things look good, so the catalogue is good to go!
September 19, 2023 at 3:21 PM
We utilize an MCMC pipeline to fit equivalent widths to all three Calcium Triplet lines i.e., 850.04 nm, 854.44 nm and 866.45 nm at the same time. We go from equivalent widths to metallicities using the Carrera+ 13 relation. It was cool to analyse spectra from the space!!
September 19, 2023 at 3:21 PM
We use publicly available Gaia RVS spectra (of ~1 million sources) and pre-select potential VMP stars from photometric (or equivalent) metallicities from Pristine DR1 and Pristine Gaia-synthetic catalogues from Martin, Starkenburg+ 23 and Table 2 giants from Andrae+ 23.
September 19, 2023 at 3:20 PM