Starbursting Nuclei in Old Dwarf Galaxies

Sanjaya Paudel, Suk Jin Yoon

Research output: Contribution to journalArticlepeer-review

Abstract

Nuclei of early-type dwarf galaxies (dEs) are usually younger than the galaxy main body, and this discrepancy in age has been a puzzle. To explore the origin of young nuclei in dEs, we study a sample of dEs having compact star-forming blobs that are visually similar to dEs' nuclei but by far bluer. We find that (1) the compact star-forming blobs have a typical stellar mass of one percent of the host galaxy stellar mass; (2) some of the blobs are positioned slightly off from the center of the galaxies; (3) the Hα equivalent width measured from the publicly available Sloan Digital Sky Survey fiber spectroscopy shows their formation ages being an order of few megayear; (4) their emission line metallicities, 12 + log(O/H), are as high as the solar value, while the underlying galaxies have the typical stellar populations of dEs, i.e., logZ/Z ∼ -0.8. Based on the results, we argue that the central star-forming blobs can provide a caught-in-the-act view of nuclei formation in dEs, and discuss possible formation mechanisms of young nuclei in old dEs. We particularly propose that these off-centered compact star-forming regions may act as seeds of nuclei as proposed in the "wet migration"scenario of Guillard et al.

Original languageEnglish
Article numberL47
JournalAstrophysical Journal Letters
Volume898
Issue number2
DOIs
Publication statusPublished - 2020 Aug

Bibliographical note

Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved..

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'Starbursting Nuclei in Old Dwarf Galaxies'. Together they form a unique fingerprint.

Cite this