VI Photometry of Globular Clusters NGC6293 and NGC6541: The Formation of the Metal-Poor Inner Halo Globular Clusters

Abstract

We present VI photometry of the metal-poor inner halo globular clusters NGC6293 and NGC6541 using the planetary camera of the WFPC2 on board HST. Our color-magnitude diagrams of the clusters show well-defined BHB populations, consistent with their low metallicities and old ages. NGC6293 appears to have blue straggler stars in the cluster's central region. We discuss the interstellar reddening and the distance modulus of NGC6293 and NGC6541 and obtain E(B-V) = 0.40 and (m-M)_0 = 14.61 for NGC6293 and E(B-V) = 0.14 and (m-M)_0 = 14.19 for NGC6541. Our results confirm that NGC6293 and NGC6541 are clearly located in the Galaxy's central regions (R_{GC} < 3 kpc). We also discuss the differential reddening across NGC6293. The interstellar reddening value of NGC6293 appears to vary by Delta E(B-V) ~ 0.02 -- 0.04 mag within our small field of view. The most notable result of our study is that the inner halo clusters NGC6293 and NGC6541 essentially have the same ages as M92, confirming the previous result from the HST NIC3 observations of NGC6287.

arXiv commentAJ, accepted

References in corpus (32)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• A Universal Density Profile from Hierarchical Clustering
• Stellar Chemical Signatures And Hierarchical Galaxy Formation
• Abundance Patterns in the Draco, Sextans and Ursa Minor Dwarf Spheroidal Galaxies
• VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies: I. Nucleosynthesis and Abundance Ratios
• Homogeneous age dating of 55 Galactic globular clusters. Clues to the Galaxy formation mechanisms
• Lambda-Cold Dark Matter, Stellar Feedback, and the Galactic Halo Abundance Pattern
• Galactic Globular Cluster Relative Ages. II
• Galactic Globular Cluster Relative Ages
• Chemical Abundance Distributions of Galactic Halos and their Satellite Systems in a Lambda CDM Universe
• Relative Frequencies of Blue Stragglers in Galactic Globular Clusters: Constraints for the Formation Mechanisms
• Blue straggler production in globular clusters
• Measuring Galactic Extinction: A Test
• Surface Brightness Profiles of Galactic Globular Clusters from Hubble Space Telescope Images
• Globular Cluster Ages and the Formation of the Galactic Halo
• Models for Old, Metal-Poor Stars with Enhanced alpha-Element Abundances. III. Isochrones and Isochrone Population Functions
• The phase-space structure of cold dark-matter halos: Insights into the Galactic halo
• NGC 2419, M92, and the Age Gradient in the Galactic Halo
• Ages for Globular Clusters in the Outer Galactic Halo: The Second Parameter Clusters Palomar~3, Palomar~4 and Eridanus
• CCD Photometry of the Classic Second Parameter Globular Clusters M3 and M13
• WFPC2 Observations of the Carina Dwarf Spheroidal Galaxy
• The Photometry of Undersampled Point Spread Functions
• Hubble Space Telescope Observations of the Oldest Star Clusters in the LMC
• Hubble Space Telescope Observations of the Draco Dwarf Spheroidal
• WFPC2 Observations of the Ursa Minor Dwarf Spheroidal Galaxy
• Age Gradient and the Second Parameter Problem in the Galactic Halo
• Chemical Abundances Of Three Metal-Poor Globular Clusters (NGC 6287, NGC 6293, And NGC 6541) In The Inner Halo
• Accurate Stellar Population Studies from Multiband Photometric Observations
• The elusive old population of the dwarf spheroidal galaxy Leo I
• A Catalog of Helium Abundance Indicators from Globular Cluster Photometry
• Blue Stragglers in Low-Luminosity Star Clusters
• RR Lyrae variables in the globular cluster M3 (NGC5272). I. BVI CCD photometry

Cited by in corpus (8)

• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope
• Uncloaking globular clusters in the inner Galaxy
• A direct measurement of the heat release in the outer crust of the transiently accreting neutron star XTE J1709-267
• The Galactic LMXB Population and the Galactic Centre Region
• Towards a better understanding of the distance scale from RR Lyrae variable stars: A case study for the inner halo globular cluster NGC 6723
• G2C2 II: Integrated colour-metallicity relations for Galactic Globular Clusters in SDSS passbands
• Relativistic Disk Reflection in the Neutron Star X-ray Binary XTE J1709-267 with NuSTAR