From the outside looking in: what can Milky Way Analogues tell us about the star formation rate of our own galaxy?

Fraser-Mckelvie, Amelia; Merrifield, Michael; Arag�n-Salamanca, Alfonso

Abstract

The Milky Way has been described as an anaemic spiral, but is its star formation rate (SFR) unusually low when compared to its peers? To answer this question, we define a sample of Milky Way Analogues (MWAs) based on stringent cuts on the best literature estimates of non-transient structural features for the Milky Way. This selection yields only 176 galaxies from the whole of the SDSS DR7 spectroscopic sample which have morphological classifications in GZ2, from which we infer SFRs from two separate indicators. The mean SFRs found are log(SFR SED /M yr −1) = 0.53 with a standard deviation of 0.23 dex from SED fits, and log(SFR W4 /M yr −1) = 0.68 with a standard deviation of 0.41 dex from a mid-infrared calibration. The most recent estimate for the Milky Way's star formation rate of log(SFR MW /M yr −1) = 0.22 fits well within 2σ of these values, where σ is the standard deviation of each of the SFR indicator distributions. We infer that the Milky Way, while being a galaxy with a somewhat low SFR, is not unusual when compared to similar galaxies.

Citation

Fraser-Mckelvie, A., Merrifield, M., & Aragón-Salamanca, A. (2019). From the outside looking in: what can Milky Way Analogues tell us about the star formation rate of our own galaxy?. Monthly Notices of the Royal Astronomical Society, 489(4), 5030–5036. https://doi.org/10.1093/mnras/stz2493

• Journal Article Type: Article
• Acceptance Date: Sep 5, 2019
• Online Publication Date: Sep 10, 2019
• Publication Date: 2019-11
• Deposit Date: Sep 13, 2019
• Publicly Available Date: Sep 13, 2019
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 489
• Issue: 4
• Pages: 5030–5036
• DOI: https://doi.org/10.1093/mnras/stz2493
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://nottingham-repository.worktribe.com/output/2613406
• Publisher URL: https://academic.oup.com/mnras/article/489/4/5030/5567191/
• Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Amelia Fraser-McKelvie, Michael Merrifield, Alfonso Aragón-Salamanca, From the outside looking in: what can Milky Way analogues tell us about the star formation rate of our own galaxy?, Monthly Notices of the Royal Astronomical Society, Volume 489, Issue 4, November 2019, Pages 5030–5036 is available online at: https://doi.org/10.1093/mnras/stz2493