2008/04/28 by Laura Chomiuk, Jay Strader, Jean P. Brodie +1 · 1 citation
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Elliptical galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Globular cluster #Hubble sequence #Hubble space telescope #Photometry (optics) #Physics #Population #Star cluster #Star formation #Stars #Stellar population #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1088/0004-6256/136/1/234
Accepted to AJ
arxiv created 2008/04/28 · openalex publication_date 2008/06/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present Hubble Space Telescope photometry and Keck spectroscopy of globular clusters (GCs) in the nearby S0 galaxy NGC 7457. The V − I color–magnitude diagram of GCs lacks the clear bimodality present in most early-type galaxies; there may be a significant population of intermediate-color objects. Of 13 spectroscopically observed GCs, two are unusually metal-rich and feature bright [O iii ] emission lines. We conclude that one probably hosts a planetary nebula and the other a supernova remnant. Such emission-line objects should be more common in an intermediate-age stellar population than in an old one. We therefore suggest that, in addition to the typical old metal-rich and old metal-poor GC subpopulations, there may be a third subpopulation of an intermediate age. Such a subpopulation may have been formed ∼2–3 Gyr ago, in the same star-forming event that dominates the stellar population of the center of the galaxy.