Delayed Stellar Mass Assembly in the Low Surface Brightness Dwarf Galaxy KDG 215

John M. Cannon; Zili Shen; Kristen B. W. McQuinn; Joshua Bartz; Lilly Bralts-Kelly; Alyssa M. Bulatek; Sarah Chinski; Robert N. Ford; Alex J. R. Gordon; Greta Helmel; Sam Hollenbach; Riley A. McGlasson; Andrew Mizener; Tylyn Page; William Retza; Moritz Rusch; Sarah Taft; Andrew E. Dolphin; Igor Karachentsev; John J. Salzer

doi:10.3847/2041-8213/aada48

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Delayed Stellar Mass Assembly in the Low Surface Brightness Dwarf Galaxy KDG 215

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Delayed Stellar Mass Assembly in the Low Surface Brightness Dwarf Galaxy KDG 215

John M. Cannon, Zili Shen, Kristen B. W. McQuinn, Joshua Bartz, Lilly Bralts-Kelly, Alyssa M. Bulatek, Sarah Chinski, Robert N. Ford, Alex J. R. Gordon, Greta Helmel, …

Astrophysical journal. Letters, Vol.864(1), p.L14

09/01/2018

DOI: 10.3847/2041-8213/aada48

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Abstract

We present H I spectral line and optical broadband images of the nearby low surface brightness dwarf galaxy KDG 215. The H I images, acquired with the Karl G. Jansky Very Large Array, reveal a dispersion-dominated interstellar medium with only weak signatures of coherent rotation. The H I gas reaches a peak mass surface density of 6 M-circle dot pc(-2) at the location of the peak surface brightness in the optical and the ultraviolet. Although KDG 215 is gas-rich, the Ha non-detection implies a very low current massive star formation rate. In order to investigate the recent evolution of this system, we have derived the recent and lifetime star formation histories from archival Hubble Space Telescope images. The recent star formation history shows a peak star formation rate similar to 1 Gyr ago, followed by a decreasing star formation rate to the present day quiescent state. The cumulative star formation history indicates that a significant fraction of the stellar mass assembly in KDG 215 has occurred within the last 1.25 Gyr. KDG 215 is one of only a few known galaxies that demonstrates such a delayed star formation history. While the ancient stellar population (predominantly red giants) is prominent, the look-back time by which 50% of the mass of all stars ever formed had been created is among the youngest of any known galaxy.

Astronomy & Astrophysics

Physical Sciences

Science & Technology

Details

Title: Subtitle: Delayed Stellar Mass Assembly in the Low Surface Brightness Dwarf Galaxy KDG 215
Creators: John M. Cannon - Macalester College
Zili Shen - The University of Texas at Austin
Kristen B. W. McQuinn - The University of Texas at Austin
Joshua Bartz - Macalester College
Lilly Bralts-Kelly - Macalester College
Alyssa M. Bulatek - Macalester College
Sarah Chinski - Macalester College
Robert N. Ford - Macalester College
Alex J. R. Gordon - Macalester Coll, Dept Phys & Astron, 1600 Grand Ave, St Paul, MN 55105 USA
Greta Helmel - Macalester College
Sam Hollenbach - Macalester College
Riley A. McGlasson - Macalester College
Andrew Mizener - Macalester College
Tylyn Page - Macalester College
William Retza - Macalester College
Moritz Rusch - Macalester College
Sarah Taft - Macalester College
Andrew E. Dolphin - RTX (United States)
Igor Karachentsev - RAS, Special Astrophys Observ, Nizhnii Arkhyz 369167, KChR, Russia
John J. Salzer - Indiana University Bloomington
Resource Type: Journal article
Publication Details: Astrophysical journal. Letters, Vol.864(1), p.L14
DOI: 10.3847/2041-8213/aada48
ISSN: 2041-8205
eISSN: 2041-8213
Publisher: Iop Publishing Ltd
Number of pages: 6
Grant note: 18-02-00005 / RFBR; Russian Foundation for Basic Research (RFBR) Macalester College
Language: English
Date published: 09/01/2018
Academic Unit: Physics and Astronomy
Record Identifier: 9984627313402771

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