Witten, Callum EC;
Aguado, David S;
Sanders, Jason L;
Belokurov, Vasily;
Evans, N Wyn;
Koposov, Sergey E;
Prieto, Carlos Allende;
... Irwin, Mike J; + view all
(2022)
Information content of BP/RP spectra in Gaia DR3.
Monthly Notices of the Royal Astronomical Society
, 516
(3)
pp. 3254-3265.
10.1093/mnras/stac2273.
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Abstract
Gaia Data Release 3 has provided the astronomical community with the largest stellar spectroscopic survey to date (> 220 million sources). The low resolution (R∼50) blue photometer (BP) and red photometer (RP) spectra will allow for the estimation of stellar atmospheric parameters such as effective temperature, surface gravity, and metallicity. We create mock Gaia BP/RP spectra and use Fisher information matrices to probe the resolution limit of stellar parameter measurements using BP/RP spectra. The best-case scenario uncertainties that this analysis provides are then used to produce a mock-observed stellar population in order to evaluate the false positive rate (FPR) of identifying extremely metal-poor stars. We conclude that the community will be able to confidently identify metal-poor stars at magnitudes brighter than G = 16 using BP/RP spectra. At fainter magnitudes true detections will start to be overwhelmed by false positives. When adopting the commonly-used G < 14 limit for metal-poor star searches, we find a FPR for the low-metallicity regimes [Fe/H] < -2, -2.5, and -3 of just 14 ${{\ \rm per\ cent}}$, 33 ${{\ \rm per\ cent}}$, and 56 ${{\ \rm per\ cent}}$ respectively, offering the potential for significant improvements on previous targeting campaigns. Additionally, we explore the chemical sensitivity obtainable directly from BP/RP spectra for carbon and α-elements. We find an absolute carbon abundance uncertainty of σA(C) < 1 dex for carbon-enriched metal-poor (CEMP) stars, indicating the potential to identify a CEMP stellar population for follow-up confirmation with higher resolution spectroscopy. Finally, we find that large uncertainties in α-element abundance measurements using BP/RP spectra means that efficiently obtaining these abundances will be challenging.
| Type: | Article |
|---|---|
| Title: | Information content of BP/RP spectra in Gaia DR3 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stac2273 |
| Publisher version: | https://doi.org/10.1093/mnras/stac2273 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. |
| Keywords: | Stars: abundances, stars: chemically peculiar, stars: fundamental parameters |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10157147 |
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