J/A+A/694/A248 Metallicity spread and dispersion among P1 stars (Latour+, 2025) ================================================================================ A stellar census in globular clusters with MUSE. Metallicity spread and dispersion among first-population stars. Latour M., Kamann S., Martocchia S., Husser T.-O., Saracino S., Dreizler S. =2025A&A...694A.248L (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Clusters, globular ; Spectroscopy ; Abundances, [Fe/H] Keywords: stars: abundances - stars: fundamental parameters - globular clusters: general Abstract: Multiple populations are ubiquitous in the old massive globular clusters (GCs) of the Milky Way. It is still unclear how they arose during the formation of a GC. The topic of iron and metallicity variations has recently attracted attention with the measurement of iron variations among the primordial population (P1) stars of Galactic GCs. We use the spectra of more than 8000 RGB stars in 21 Galactic GCs observed with MUSE to derive individual stellar metallicities [M/H]. For each cluster, we use the HST photometric catalogs to separate the stars into two main populations (P1 and P2). We measure the metallicity spread within the primordial population of each cluster by combining our metallicity measurements with the stars {Delta}_F275W,F814W_ pseudo-color. We also derive metallicity dispersions ({sigma}_[M/H]_) for the P1 and P2 stars of each GC. In all but three GCs, we measure a significant correlation between the metallicity and the {Delta}_F275W,F814W_ pseudo-color of the P1 stars such that stars with larger {Delta_F275W,F814W_ have higher metallicities. We measure metallicity spreads that range from 0.03 to 0.24dex and correlate with the GC masses. As for the intrinsic metallicity dispersions, when combining the P1 and P2 stars, we measure values ranging from 0.02 dex to 0.08dex that correlate very well with the GC masses. We compared the metallicity dispersion among the P1 and P2 stars and found that the P2 stars have metallicity dispersions that are smaller or equal to that of the P1 stars. We find that both the metallicity spreads of the P1 stars (from the {Delta_F275W,F814W_ spread in the chromosome maps) and the metallicity dispersions ({sigma_[M/H]_) correlate with the GC masses, as predicted by some theoretical self-enrichment models presented in the literature. Description: We provide various measurements for the stars that are included in our samples of both P1 and P2 stars in the 21 Globular clusters. The star identification numbers are unique per cluster. The surface gravity (logg) is obtained from the position of the star in the CMD when compared to an isochrone. The effective temperature and metallicity are derived from a full fit of the MUSE spectra. The values are then averaged over the number of spectra available for a given star. The metallicity that we measured is an overal one, and is not a direct iron abundance measurement. We also include the coordinates of the star in our chromosome maps. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 132 8382 Properties of the RGB stars in our spectral sample -------------------------------------------------------------------------------- See also: J/A+A/635/A114 : EW and [Fe/H] for 30000 globular cluster RGB stars (Husser+ 2020) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 2- 7 I6 --- Source Star identification number 10- 20 F11.7 deg RAdeg Right ascension (J2000) 23- 33 F11.7 deg DEdeg Declination (J2000) 36- 42 A7 --- Cluster Cluster name 46- 51 F6.3 [Sun] [M/H] Metallicity 54- 58 F5.3 [Sun] e_[M/H] Error on the metallicity 65- 68 I4 K Teff Effective temperature 75- 76 I2 K e_Teff Error on the effective temperature 79- 81 I3 --- SNR Average signal-to-noise of the Nspec spectra 86- 87 I2 --- Nspec Number of spectra used to average Teff and [M/H] 93- 97 F5.3 [cm/s2] logg Surface gravity 102-106 F5.3 [cm/s2] e_logg Error on the surface gravity (1) 109-115 F7.4 --- CMx Delta(F275W,F814W), X-axis position on the Chromosome map 118-124 F7.4 --- CMy DeltaC(F275W,F336W,F438W), Y-axis position on the Chromosome map 128 I1 --- P1 [0/1] =1 if the star belongs to P1 132 I1 --- P2 [0/1] =1 if the star belongs to P2 -------------------------------------------------------------------------------- Note (1): For three clusters there is not uncertainty (=0) on the surface gravity measurements because it was obtained with only one set of photometry. -------------------------------------------------------------------------------- Acknowledgements: Marilyn Latour, marilyn.latour(at)uni-goettingen.de ================================================================================ (End) Patricia Vannier [CDS] 21-Jan-2025