UVIT study of UV bright stars in the globular cluster NGC 4147

Abstract

We present far ultraviolet (FUV) observations of globular cluster NGC 4147 using three FUV filters, BaF2 (F154W), Sapphire (F169M), and Silica (F172M) of Ultra-Violet Imaging Telescope (UVIT) on-board the \mbox{\em AstroSat} satellite. We confirmed the cluster membership of the UVIT observed sources using proper motions from Gaia data release 2 (GAIA DR2). We identified 37 blue horizontal branch stars (BHBs), one blue straggler star (BSS) and 15 variable stars using UV-optical color magnitude diagrams (CMDs). We find that all the FUV bright BHBs are second generation population stars. Using UV-optical CMDs, we identify two sub-populations, BHB1 and BHB2, among the UV-bright BHBs in the cluster with stars count ratio of 24:13 for BHB1 and BHB2. The effective temperatures (T${}_{\mathrm{eff}}$) of BHB1 and BHB2 were derived using color-temperature relation of BaSTI-IAC zero-age horizontal branch (ZAHB). We found that BHB1 stars are more centrally concentrated than BHB2 stars. We also derive physical parameters of the detected FUV bright BSS by fitting younger age BaSTI-IAC isochrones on optical and UV-optical CMDs.

Accepted for publication in JOAA special issue "ASTROSAT-5years"

References in corpus (19)

• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• What is a globular cluster? An observational perspective
• A Binary Origin for Blue Stragglers in Globular Clusters
• Additional Calibration of the Ultra-Violet Imaging Telescope on board AstroSat
• Homogeneous photometry VII. Globular clusters in the Gaia era
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIX. A Chemical Tagging of the Multiple Stellar Populations Over the Chromosome Maps
• Deep Mixing and Metallicity: Carbon Depletion in Globular Cluster Giants
• Mass loss along the red giant branch in 46 Globular Clusters and their multiple populations
• UVIT Open Cluster Study. II. Detection of extremely low mass white dwarfs and post-mass transfer binaries in M67
• Detection of a White Dwarf companion to a Blue Straggler Star in the outskirts of globular cluster NGC 5466 with the Ultraviolet Imaging Telescope (UVIT)
• Multiple populations in massive star clusters under the magnifying glass of photometry: Theory and tools
• The Horizontal Branch population of NGC 1851 as revealed by the Ultra-violet Imaging Telescope (UVIT)
• Peculiarities in the horizontal branch stars of globular cluster NGC 1851: Discovery of a Blue straggler companion to an EHB star
• Investigation of the Globular Cluster NGC 2808 with the Ultra-Violet Imaging Telescope
• Ultraviolet Imaging Telescope (UVIT) observation of the Galactic Globular Cluster NGC 7492
• VR CCD photometry of variable stars in globular cluster NGC 4147
• The Horizontal Branch morphology of the globular cluster NGC 1261 using AstroSat
• UVIT Observations of UV-Bright Stars in four Galactic Globular Clusters

Cited by in corpus (4)

• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• Study of UV bright sources in globular cluster NGC 4590 using Ultraviolet Imaging Telescope (UVIT) observations
• Optical Observations of star clusters NGC 1513 and NGC 4147; white dwarf WD1145+017 and $K$ band imaging of star forming region Sh2-61 with the 3.6 meter Devasthal Optical Telescope
• Globular Cluster UVIT Legacy Survey (GlobULeS) $-$ II. Evolutionary status of hot stars in M3 and M13