Information content of BP/RP spectra in Gaia DR3

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$\sim$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 (EMP) 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$\%$, 33$\%$ and 56$\%$ 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 $\alpha$-elements. We find an absolute Carbon abundance uncertainty of ${\sigma }_{A(C)}<1$ 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 $\alpha$-element abundance measurements using BP/RP spectra means that efficiently obtaining these abundances will be challenging.

12 pages, 9 figures, 1 table. Accepted for publication in MNRAS

References in corpus (19)

• The Gaia mission
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Nucleosynthetic signatures of the first stars
• Carbon-Enhanced Metal-Poor Star Frequencies in the Galaxy: Corrections for the Effect of Evolutionary Status on Carbon Abundances
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5
• Observational Constraints on First-Star Nucleosynthesis. I. Evidence for Multiple Progenitors of CEMP-no Stars
• Bright Metal-Poor Stars from the Hamburg/ESO Survey. I. Selection and Follow-up Observations from 329 Fields
• TOPoS: II. On the bimodality of carbon abundance in CEMP stars. Implications on the early chemical evolution of galaxies
• Center-to-Limb Variation of Solar 3-D Hydrodynamical Simulations
• Internal calibration of Gaia BP/RP low-resolution spectra
• The Best and Brightest Metal-Poor Stars
• Elevated r-process enrichment in Gaia Sausage and Sequoia
• Faint Population III supernovae as the origin of the most iron-poor stars
• Pristine IX: CFHT ESPaDOnS Spectroscopic Analysis of 115 Bright Metal-Poor Candidate Stars
• WHT follow-up observations of extremely metal-poor stars identified from SDSS and LAMOST
• The Pristine Inner Galaxy Survey (PIGS) III: carbon-enhanced metal-poor stars in the bulge
• Targeting Bright Metal-poor Stars in the Disk and Halo Systems of the Galaxy
• Estimating $\left[\alpha /\text{Fe}\right]$ from Gaia low-resolution BP/RP spectra using the ExtraTrees algorithm
• Learning about stars from their colors

Cited by in corpus (13)

• Parameters of 220 million stars from Gaia BP/RP spectra
• Galactic Archaeology with Gaia
• The Pristine survey -- XXIII. Data Release 1 and an all-sky metallicity catalogue based on Gaia DR3 BP/RP spectro-photometry
• Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost
• Carbon-Enhanced Metal-Poor star candidates from BP/RP Spectra in $Gaia$ DR3
• Hunting for C-rich long-period variable stars in the Milky Way's bar-bulge using unsupervised classification of Gaia BP/RP spectra
• Predicting metallicities and carbon abundances from Gaia XP spectra for (carbon-enhanced) metal-poor stars
• The Pristine survey: XXV. The very metal-poor Galaxy: Chemodynamics through the follow-up of the Pristine-Gaia synthetic catalogue
• Metallicity and $\alpha$-abundance for 48 million stars in low-extinction regions in the Milky Way
• Mapping the Milky Way with Gaia Bp/Rp spectra I: Systematic flux corrections and atmospheric parameters for 68 million stars
• Closing the stellar labels gap: Stellar label independent evidence for [$\alpha /M$] information in Gaia BP/RP spectra
• The ones that got away: chemical tagging of globular cluster-origin stars with Gaia BP/RP spectra
• A Catalog of 12,766 Carbon-enhanced Metal-poor Stars from LAMOST Data Release 8