CHARACTERIZING THE STAR FORMATION OF THE LOW-MASS SHIELD GALAXIES FROM HUBBLE SPACE TELESCOPE IMAGING

Kristen. B. W. McQuinn; John M. Cannon; Andrew E. Dolphin; Evan D. Skillman; Martha P. Haynes; Jacob E. Simones; John J. Salzer; Elizabeth A. K. Adams; Ed C. Elson; Riccardo Giovanelli; Juergen Ott

doi:10.1088/0004-637X/802/1/66

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CHARACTERIZING THE STAR FORMATION OF THE LOW-MASS SHIELD GALAXIES FROM HUBBLE SPACE TELESCOPE IMAGING

Journal article

Peer reviewed

CHARACTERIZING THE STAR FORMATION OF THE LOW-MASS SHIELD GALAXIES FROM HUBBLE SPACE TELESCOPE IMAGING

Kristen. B. W. McQuinn, John M. Cannon, Andrew E. Dolphin, Evan D. Skillman, Martha P. Haynes, Jacob E. Simones, John J. Salzer, Elizabeth A. K. Adams, Ed C. Elson, Riccardo Giovanelli, …

The Astrophysical journal, Vol.802(1), p.66

03/20/2015

DOI: 10.1088/0004-637X/802/1/66

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https://arxiv.org/pdf/1501.07313View

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Abstract

The Survey of HI in Extremely Low-mass Dwarfs is an on-going multi-wavelength program to characterize the gas, star formation, and evolution in gas-rich, very low-mass galaxies that populate the faint end of the galaxy luminosity function. The galaxies were selected from the first similar to 10% of the HI Arecibo Legacy Fast ALFA survey based on their low HI mass and low baryonic mass. Here, we measure the star formation properties from optically resolved stellar populations for 12 galaxies using a color-magnitude diagram fitting technique. We derive lifetime average star formation rates (SFRs), recent SFRs, stellar masses, and gas fractions. Overall, the recent SFRs are comparable to the lifetime SFRs with mean birthrate parameter of 1.4, with a surprisingly narrow standard deviation of 0.7. Two galaxies are classified as dwarf transition galaxies (dTrans). These dTrans systems have star formation and gas properties consistent with the rest of the sample, in agreement with previous results that some dTrans galaxies may simply be low-luminosity dwarf irregulars. We do not find a correlation between the recent star formation activity and the distance to the nearest neighboring galaxy, suggesting that the star formation process is not driven by gravitational interactions, but regulated internally. Further, we find a broadening in the star formation and gas properties (i.e., specific SFRs, stellar masses, and gas fractions) compared to the generally tight correlation found in more massive galaxies. Overall, the star formation and gas properties indicate these very low-mass galaxies host a fluctuating, non-deterministic, and inefficient star formation process.

Astronomy & Astrophysics

Physical Sciences

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Title: Subtitle: CHARACTERIZING THE STAR FORMATION OF THE LOW-MASS SHIELD GALAXIES FROM HUBBLE SPACE TELESCOPE IMAGING
Creators: Kristen. B. W. McQuinn - University of Minnesota
John M. Cannon - Macalester College
Andrew E. Dolphin - RTX (United States)
Evan D. Skillman - University of Minnesota
Martha P. Haynes - Cornell University
Jacob E. Simones - University of Minnesota
John J. Salzer - Indiana University Bloomington
Elizabeth A. K. Adams - Netherlands Institute for Radio Astronomy
Ed C. Elson - University of Cape Town
Riccardo Giovanelli - Cornell University
Juergen Ott - National Radio Astronomy Observatory
Resource Type: Journal article
Publication Details: The Astrophysical journal, Vol.802(1), p.66
DOI: 10.1088/0004-637X/802/1/66
ISSN: 0004-637X
eISSN: 1538-4357
Publisher: Iop Publishing Ltd
Number of pages: 12
Grant note: NRAO AST-1211683; AST-1107390 / NSF; National Science Foundation (NSF) 1211683 / Division Of Astronomical Sciences; National Science Foundation (NSF); NSF - Directorate for Mathematical & Physical Sciences (MPS) Brinson Foundation GO-12658 / NASA from the Space Telescope Institute NAS5-26555 / Aura, Inc., under NASA
Language: English
Date published: 03/20/2015
Academic Unit: Physics and Astronomy
Record Identifier: 9984627297402771

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