Lifting the dust veil from the Globular Cluster Palomar2

Abstract

This work employs high-quality {\em Hubble Space Telescope} ({\em HST}) Advanced Camera for Surveys (ACS) F606W and F814W photometry to correct for the differential reddening affecting the colour-magnitude diagram (CMD) of the poorly-studied globular cluster (GC) Palomar\,2. Differential reddening is taken into account by assuming that morphological differences among CMDs extracted across the field of view of Palomar\,2 correspond essentially to shifts (quantified in terms of $\delta E(B-V)$) along the reddening vector due to a non-uniform dust distribution. The average reddening difference over all partial CMDs is $\overline{\delta E(B-V)}=0.24\pm 0.08$, with the highest reaching $\delta E(B-V)=0.52$. The corrected CMD displays well-defined and relatively narrow evolutionary sequences, especially for the evolved stars, i.e. the red-giant, horizontal and asymptotic giant branches (RGB, HB and AGB, respectively). The average width of the upper main sequence and RGB profiles of the corrected CMD corresponds to 56\% of the original one. Parameters measured on this CMD show that Palomar\,2 is $\approx 13.25$\,Gyr old, has the mass $M\sim 1.4\times 10^5{m}_{\odot }$ stored in stars, is affected by the foreground $E(B-V)\approx 0.93$, is located at $d_{\odot }\approx 26$\,Kpc from the Sun, and is characterized by the global metallicity $Z/Zo\approx 0.03$, which corresponds to the range $-1.9\le [Fe/H]\le -1.6$ (for $0.0\le [\alpha /Fe]\le +0.4$), quite consistent with other outer halo GCs. Additional parameters are the absolute magnitude $M_V\approx -7.8$, and the core and half-light radii $r_C\approx 2.6$\,pc and $R_{HL}\approx 4.7$\,pc, respectively.

arXiv commentAccepted for publication by MNRAS

References in corpus (31)

• Gaia Data Release 2. Summary of the contents and survey properties
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• A new generation of PARSEC-COLIBRI stellar isochrones including the TP-AGB phase
• Co-formation of the Galactic disc and the stellar halo
• Multiple populations in globular clusters. Lessons learned from the Milky Way globular clusters
• Multiple Stellar Populations in Globular Clusters
• Gaia Data Release 2: Kinematics of globular clusters and dwarf galaxies around the Milky Way
• Debris streams in the solar neighbourhood as relicts from the formation of the Milky Way
• Eight New Milky Way Companions Discovered in First-Year Dark Energy Survey Data
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• Origin of the system of globular clusters in the Milky Way
• An ACS Survey of Globular Clusters V: Star Catalog for Each Cluster
• Stellar Streams Discovered in the Dark Energy Survey
• The Bifurcated Age-Metallicity Relation of Milky Way Globular Clusters and its Implications For the Accretion History of the Galaxy
• Accreted versus In Situ Milky Way Globular Clusters
• Globular clusters in the outer Galactic halo: new HST/ACS imaging of 6 globular clusters and the Galactic globular cluster age-metallicity relation
• Globular cluster system and Milky Way properties revisited
• The Southern Stellar Stream Spectroscopic Survey ($S^5$): Overview, Target Selection, Data Reduction, Validation, and Early Science
• A New Catalog of Globular Clusters in the Milky Way
• ATLAS lifts the Cup: Discovery of a New Milky Way satellite in Crater
• Fourteen candidate RR Lyrae star streams in the inner Galaxy
• Understanding the Dynamical State of Globular Clusters: Core-Collapsed vs Non Core-Collapsed
• Tidal disruption of globular clusters in dwarf galaxies with triaxial dark matter haloes
• Analysis of the physical nature of 22 New VVV Survey Globular Cluster candidates in the Milky Way Bulge
• Mapping the differential reddening in globular clusters
• Star clusters as laboratories for stellar and dynamical evolution
• J-PLUS: A wide-field multi-band study of the M15 globular cluster. Evidence of multiple stellar populations in the RGB
• An efficient approach to extract parameters from star cluster CMDs: fitCMD
• Unveiling hidden properties of young star clusters: differential reddening, star-formation spread and binary fraction
• Stellar populations in star clusters
• Unveiling Palomar 2: The Most Obscure Globular Cluster in the Outer Halo

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• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• Canis Major OB1 stellar groups contents revealed by Gaia
• S-PLUS: Exploring wide field properties of multiple populations in galactic globular clusters at different metallicities