The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of Single and Multiple Stellar Populations in Seven Bulge Globular Clusters

Oliveira, R. A. P.; Souza, Stefano O.; Kerber, Leandro; Barbuy, B.; Ortolani, S.; Piotto, G.; Nardiello, D.; Pérez-Villegas, Ángeles; Maia, F. F. S.; Bica, E.; Cassisi, S.; D’Antona, Francesca; Lagioia, E. P.; Libralato, Mattia; Milone, A. P.; Anderson, Jay; Aparicio, A.; Bedin, L. R.; Brown, Thomas M.; King, Ivan R.; Marino, A. F.; Pietrinferni, A.; Renzini, A.; Sarajedini, Ata; Marel, Roeland van der; Vesperini, Enrico

doi:10.3847/1538-4357/ab6f76

Cited by 28 publications

(6 citation statements)

References 128 publications

(155 reference statements)

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“…The remainder of our sample is relatively old, to a remarkably consistent extent: Their mean age is 12.9±0.4 Gyr, at least as old as any other component of the MWGC age-metallicity relation. This is in excellent agreement with a mean age of 12.86±0.36 Gyr for metal-intermediate (−1.5 [Fe/H] −0.85) bulge globulars quoted by Oliveira et al (2020), who compiled literature ages to update a similar analysis by Saracino et al (2019). However, these age measurements are quite heterogenous, derived using observations in different bandpasses, different age measurement techniques, and in some cases different evolutionary models and different bolometric corrections.…”

Section: The Age-metallicity Relationsupporting

confidence: 86%

Relative Ages of Nine Inner Milky Way Globular Clusters from Proper Motion Cleaned Color-Magnitude Diagrams

Cohen,

Bellini,

Casagrande

et al. 2021

Preprint

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Our picture of the age-metallicity relation for Milky Way globular clusters (MWGCs) is still highly incomplete, and the majority of MWGCs lack self-consistent age measurements. Here, we exploit deep, homogenous multi-epoch Hubble Space Telescope (HST ) imaging of nine MWGCs located towards the inner Milky Way to measure their relative ages, in most cases for the first time. Our relative age measurements are designed to be directly comparable to the large set of MWGC ages presented by VandenBerg et al. 2013 (V13), using identical filters, evolutionary models, and bolometric corrections, extended to the higher extinction values relevant to our target clusters. Adopting the V13 MWGC age scale, our relative age measurements imply that our target clusters are consistently very old, with a mean age of 12.9±0.4 Gyr, with the exception of the young metal-rich MWGC NGC 6342. We perform two tests to validate the precision of our methodology, and discuss the implications of our target cluster loci in the MWGC age-metallicity plane. In addition, we use our fully self-consistent bolometric corrections to assess the systematic impact of variations in the total-to-selective extinction ratio R V on relative age measurements.

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Section: The Age-metallicity Relationsupporting

confidence: 86%

Relative Ages of Nine Inner Milky Way Globular Clusters from Proper Motion Cleaned Color-Magnitude Diagrams

Cohen,

Bellini,

Casagrande

et al. 2021

Preprint

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“…We also tested how H 0 can be constrained with the individual very oldest globular clusters with the smallest age errors. For NGC 6362 (13.6 ± 0.5 Gyr) (Oliveira et al 2020) and NGC 6779 (14.9 +0.5 −0.9 Gyr) (Valcin et al 2020), we obtain 68.5 +2.9 −3.2 and 63.1 +3.9 −4.5 km/s/Mpc, respectively. Taken at face value, this exercise highlights the importance of the oldest objects in the context of the Hubble tension.…”

Section: Individual Agesmentioning

confidence: 71%

Revisiting oldest stars as cosmological probes: new constraints on the Hubble constant

Cimatti¹,

Moresco²

2023

Preprint

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Despite the tremendous advance of observational cosmology, the value of the Hubble constant (H 0 ) is still controversial (the so called "Hubble tension") because of the inconsistency between local/late-time measurements and those derived from the cosmic microwave background. As the age of the Universe is very sensitive to H 0 , we explored whether the present-day oldest stars could place independent constraints on the Hubble constant. To this purpose, we selected from the literature the oldest objects (globular clusters, stars, white dwarfs, ultra-faint and dwarf spheroidal galaxies) with accurate age estimates. Adopting a conservative prior on their formation redshifts (11 ≤ z f ≤ 30) and assuming Ω M = 0.3 ± 0.02, we developed a method based on Bayesian statistics to estimate the Hubble constant. We selected the oldest objects (> 13.3 Gyr), and estimated H 0 both for each of them individually and for the average ages of homogeneous subsamples. Statistical and systematic uncertainties were properly taken into account. The constraints based on individual ages indicate that H 0 < 70.6 km/s/Mpc when selecting the most accurate estimates. If the ages are averaged and analyzed independently for each subsample, the most stringent constraints imply H 0 < 73.0 with a probability of 93.2% and errors around 2.5 km/s/Mpc. We also constructed an "accuracy matrix" to assess how the constraints on H 0 become more stringent with further improvements in the accuracy of stellar ages and Ω M . The results show the high potential of the oldest stars as independent and competitive cosmological probes.

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“…We also tested how H 0 can be constrained with the individual very oldest globular clusters with the smallest age errors. For NGC 6362 (13.6 ± 0.5 Gyr) (Oliveira et al 2020) and NGC 6779 (14.9 0.9 0.5 -+ Gyr) (Valcin et al 2020), we obtain 68.5 3.2 2.9 -+ and 63.1 4.5 3.9 -+ km s −1 Mpc −1 , respectively. Taken at face value, this exercise highlights the importance of the oldest objects in the context of the Hubble tension.…”

Section: Individual Agesmentioning

confidence: 71%

“…). For our purpose, we focused on the most recent results of O'Malley et al (2017),Brown et al (2018),Oliveira et al (2020), andValcin et al (2020) with state-of-art age dating and a careful assessment of the statistical and systematic uncertainties. The oldest GCs have ages 13.5 Gyr with total errors (i.e., combined statistical and systematic) from ∼0.5 Gyr to 1 Gyr.…”

mentioning

confidence: 99%

Revisiting the Oldest Stars as Cosmological Probes: New Constraints on the Hubble Constant

Cimatti

Moresco

2023

ApJ

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Despite the tremendous advance of observational cosmology, the value of the Hubble constant (H 0) is still controversial (the so-called “Hubble tension”) because of the inconsistency between local/late-time measurements and those derived from the cosmic microwave background. As the age of the Universe is very sensitive to H 0, we explored whether the present-day oldest stars could place independent constraints on the Hubble constant. To this purpose, we selected from the literature the oldest objects (globular clusters, stars, white dwarfs, and ultrafaint and dwarf spheroidal galaxies) with accurate age estimates. Adopting a conservative prior on their formation redshifts (11 ≤ z f ≤ 30) and assuming Ω M = 0.3 ± 0.02, we developed a method based on Bayesian statistics to estimate the Hubble constant. We selected the oldest objects (>13.3 Gyr) and estimated H 0 both for each of them individually and for the average ages of homogeneous subsamples. Statistical and systematic uncertainties were properly taken into account. The constraints based on individual ages indicate that H 0 < 70.6 km s−1 Mpc−1 when selecting the most accurate estimates. If the ages are averaged and analyzed independently for each subsample, the most stringent constraints imply H 0 < 73.0 km s−1 Mpc−1 with a probability of 90.3% and errors around 2.5 km s−1 Mpc−1. We also constructed an “accuracy matrix” to assess how the constraints on H 0 become more stringent with further improvements in the accuracy of stellar ages and Ω M . The results show the great potential of the oldest stars as independent and competitive cosmological probes not limited to just the Hubble constant.

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The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of Single and Multiple Stellar Populations in Seven Bulge Globular Clusters

Cited by 28 publications

References 128 publications

Relative Ages of Nine Inner Milky Way Globular Clusters from Proper Motion Cleaned Color-Magnitude Diagrams

Relative Ages of Nine Inner Milky Way Globular Clusters from Proper Motion Cleaned Color-Magnitude Diagrams

Revisiting oldest stars as cosmological probes: new constraints on the Hubble constant

Revisiting the Oldest Stars as Cosmological Probes: New Constraints on the Hubble Constant

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