Nevermind Season 8 of Game of Thrones, this is the biggest unveiling of 2019 – the official results of the Lancaster Astrophysics Metal-poor Star Search. So without further ado, LAMPSS present 16 potentially extremely metal-poor ([Fe/H] <-3.0) stars:
Once we had applied our conditions for stars, spectral type and metallicity, we had our metal-poor candidates. The nature of candidates was manually checked the source using Hubble Space Telescope imagery (https://irsa.ipac.caltech.edu/data/COSMOS/index_cutouts.html) to ensure the sources were not galaxies. Whilst doing so we found some interesting galaxies:
We compared our metal-poor candidates with that of WARP. A project running parallel to ours that used INT data, rather than CFHT. We found a definite correlation between two sets of sources:
We studied a parameter space that has never been explored before, so, in order to make more meaningful, general comparisons we calculated stellar number densities using the volumes calculated in week 4. By then applying the (g-i) conditions for spectral type, we plotted the number density per spectral type per metallicity for the region of halo surveyed (figure 5). Again, we checked our results against WARPs (figure 6).
Admittedly, our project has several limitations. All of our predictions are based on the fact that a star lies on the main sequence, however many stars we surveyed will be at different stages in their evolution, thereby making our predictions inaccurate. Additionally, many of the candidates shown in figure 1 are K type stars and, as mentioned in the last blog post, some extrapolation is required to apply our metallicity conditions to K type stars. However, applying Davids old adage – “Within a factor of 10 is fine” – we remain confident that the LAMPSS metal-poor stars are indeed just that.
So that brings our project to a conclusion. We have written a report ( LAMPSS: Discovery of Metal-Poor Stars in the Galactic Halo with the CaHK filter on CFHT MegaCam (Worrell et al. 2019)), which was submitted very comfortably before the deadline. Now all that remains is a presentation at the PLACE conference (4th/5th June). I’d like to thank David Sobral for his considerable help and guidance throughout the project, as well as the rest of LAMPSS for being stellar.
as you were JB x