IMF-induced intrinsic uncertainties on measuring galaxy distances based on the number of giant stars: the case of the ultra-diffuse galaxy NGC 1052-DF2

Abstract

The surface brightness fluctuation (SBF) technique is one of the distance measurement methods that has been applied on the low surface brightness galaxy NGC 1052-DF2 yielding a distance of about 20 Mpc implying it to be a dark matter deficient galaxy. We assume the number of giant stars above a given luminosity threshold to represent the SBF magnitude. The SBF magnitude depends on the distance, but this is degenerate with the star formation history (SFH). Using a stellar population synthesis model we calculate the number of giant stars for stellar populations with different galaxy-wide stellar initial mass functions (gwIMFs), ages, metallicities and SFHs. If the gwIMF is the invariant canonical IMF, the 1$\sigma$ (3$\sigma$) uncertainty in colour allows a distance as low as 12 Mpc (8 Mpc). If instead the true underlying gwIMF is the integrated galaxy-wide IMF (IGIMF) then overestimating distances for low-mass galaxies would be a natural result, allowing NGC 1052-DF2 to have a distance of 11 Mpc within the 1$\sigma$ colour uncertainty. Finally, we show that our main conclusion on the existence of a bias in the SBF distance estimation is not much affected by changing the luminosity lower limit for counting giant stars.

Accepted for publication in MNRAS. 9 pages, 7 figures, updated according to the received comments

References in corpus (17)

• Evolution of asymptotic giant branch stars I. Updated synthetic TP-AGB models and their basic calibration
• An excess of massive stars in the local 30 Doradus starburst
• A second galaxy missing dark matter in the NGC1052 group
• The optimally-sampled galaxy-wide stellar initial mass function - Observational tests and the publicly available GalIMF code
• The ultra-diffuse galaxy NGC 1052-DF2 with MUSE: II. The population of DF2: stars, clusters and planetary nebulae
• The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. IV. A Super-Salpeter IMF in the center of NGC 1407 from Non-Parametric Models
• Using Surface Brightness Fluctuations to Study Nearby Satellite Galaxy Systems: Calibration and Methodology
• Type Ibc supernovae in disturbed galaxies: evidence for a top-heavy IMF
• Joint Analysis of near-infrared properties and surface brightness fluctuations of LMC star clusters
• The formation of UCDs and massive GCs: Quasar-like objects for testing for a variable stellar initial mass function (IMF)
• The young stellar population of NGC 4214 as observed with HST. II. Results
• Are ultra-diffuse galaxies Milky Way-sized?
• First results from SAPAC: towards a 3D-picture of the Fornax cluster core
• The Globular Cluster Population of NGC 1052-DF2: Evidence for Rotation
• Stellar content, planetary nebulae, and globular clusters of [KKS2000]04 (NGC1052-DF2)
• Surface Brightness Fluctuations as Primary and Secondary Distance Indicators
• Evolution of star clusters on eccentric orbits: semi-analytical approach

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