English

Spatially-Resolved Recent Star Formation History in NGC 6946

Astrophysics of Galaxies 2023-07-12 v1

Abstract

The nearby face-on star forming spiral galaxy NGC 6946 is known as the Fireworks Galaxy due to its hosting an unusually large number of supernova. We analyze its resolved near-ultraviolet (NUV) stellar photometry measured from images taken with the Hubble Space Telescope's (HST) Wide Field Camera 3 (WFC3) with F275W and F336W filters. We model the color-magnitude diagrams (CMD) of the UV photometry to derive the spatially-resolved star formation history (SFH) of NGC 6946 over the last 25 Myr. From this analysis, we produce maps of the spatial distribution of young stellar populations and measure the total recent star formation rate (SFR) of nearly the entire young stellar disk. We find the global SFR(age\leq25 Myr)=13.17+0.910.79M/yr13.17 \substack{+0.91 \\-0.79} M_\odot/\rm yr. Over this period, the SFR is initially very high (23.39+2.432.11M/yr23.39\substack{+2.43\\-2.11} M_\odot/\rm yr between 16-25 Myr ago), then monotonically decreases to a recent SFR of 5.31+0.190.17M/yr5.31\substack{+0.19\\-0.17} M_\odot/\rm yr in the last 10 Myr. This decrease in global star formation rate over the last 25 Myr is consistent with measurements made with other SFR indicators. We discuss in detail two of the most active regions of the galaxy, which we find are responsible for 3% and 5% of the total star formation over the past 6.3 Myr.

Keywords

Cite

@article{arxiv.2307.04853,
  title  = {Spatially-Resolved Recent Star Formation History in NGC 6946},
  author = {Debby Tran and Benjamin Williams and Emily Levesque and Margaret Lazzarini and Julianne Dalcanton and Andrew Dolphin and Brad Koplitz and Adam Smercina and O. Grace Telford},
  journal= {arXiv preprint arXiv:2307.04853},
  year   = {2023}
}

Comments

19 pages, 11 figures, accepted for publication in ApJ