Size–Luminosity Scaling Relations of Local and Distant Star-forming Regions
Abstract
We investigate star forming scaling relations using Bayesian inference on a comprehensive data sample of low- (z < 0.1) and high-redshift (1 < z < 5) star forming regions. This full data set spans a wide range of host galaxy stellar mass (M∗∼10^6−10^(11)M⊙) and clump star formation rates (SFR ∼10^(−5)−10^2M⊙yr^(−1)). We fit the power-law relationship between the size (r_(Hα)) and luminosity (L_(Hα)) of the star forming clumps using the Bayesian statistical modeling tool Stan that makes use of Markov Chain Monte Carlo (MCMC) sampling techniques. Trends in the scaling relationship are explored for the full sample and subsets based on redshift and selection effects between samples. In our investigation we find no evidence of redshift evolution of the size-luminosity scaling relationship, nor a difference in slope between lensed and unlensed data. There is evidence of a break in the scaling relationship between high and low star formation rate surface density (Σ_(SFR)) clumps. The size-luminosity power law fit results are L_(Hα) ∼ r^(2.8)_(Hα) and L_(Hα) ∼ r^(1.7)_(Hα) for low and high Σ_(SFR) clumps, respectively. We present a model where star forming clumps form at locations of gravitational instability and produce an ionized region represented by the Strömgren radius. A radius smaller than the scale height of the disk results in a scaling relationship of L ∝ r^3 (high Σ_(SFR) clumps), and a scaling of L ∝ r2^ (low Σ_(SFR) clumps) if the radius is larger than the disk scale height.
Additional Information
© 2018 The American Astronomical Society. Received 2018 July 13; revised 2018 October 19; accepted 2018 October 23; published 2018 December 6. The authors wish to thank Randy Campbell and Jim Lyke for their assistance at the telescope to acquire the Keck OSIRIS data sets. We appreciate the valuable discussions with Dusan Keres and Karin Sandstrom. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this precious mountain. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Facility: Keck:I (OSIRIS). - Software: PyStan (Stan Development Team 2017b), OSIRIS Data Reduction Pipeline (Lyke et al. 2017), Matplotlib (Hunter 2007).Attached Files
Published - Cosens_2018_ApJ_869_11.pdf
Accepted Version - 1810.10494.pdf
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Additional details
- Eprint ID
- 91533
- Resolver ID
- CaltechAUTHORS:20181206-100759133
- W. M. Keck Foundation
- NASA/JPL/Caltech
- Created
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2018-12-06Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)