Evolution of Intrinsic Scatter in the SFR-Stellar Mass Correlation at 0.5 < z < 3

March 2016 • 2016ApJ...820L...1K

Authors • Kurczynski, Peter • Gawiser, Eric • Acquaviva, Viviana • Bell, Eric F. • Dekel, Avishai • de Mello, Duilia F. • Ferguson, Henry C. • Gardner, Jonathan P. • Grogin, Norman A. • Guo, Yicheng • Hopkins, Philip F. • Koekemoer, Anton M. • Koo, David C. • Lee, Seong-Kook • Mobasher, Bahram • Primack, Joel R. • Rafelski, Marc • Soto, Emmaris • Teplitz, Harry I.

Abstract • We present estimates of intrinsic scatter in the star formation rate (SFR)-stellar mass (M_*) correlation in the redshift range 0.5< z< 3.0 and in the mass range {10}⁷< {M}_*< {10}¹¹M_⊙. We utilize photometry in the Hubble Ultradeep Field (HUDF12) and Ultraviolet Ultra Deep Field (UVUDF) campaigns and CANDELS/GOODS-S and estimate SFR, M_* from broadband spectral energy distributions and the best-available redshifts. The maximum depth of the UDF photometry (F160W 29.9 AB, 5σ depth) probes the SFR-M_* correlation down to {M}_*\quad ∼ 10⁷M_⊙, a factor of 10-100× lower in M_* than previous studies, and comparable to dwarf galaxies in the local universe. We find the slope of the SFR-M_* relationship to be near unity at all redshifts and the normalization to decrease with cosmic time. We find a moderate increase in intrinsic scatter with cosmic time from 0.2 to 0.4 dex across the epoch of peak cosmic star formation. None of our redshift bins show a statistically significant increase in intrinsic scatter at low mass. However, it remains possible that intrinsic scatter increases at low mass on timescales shorter than ∼100 Myr. Our results are consistent with a picture of gradual and self-similar assembly of galaxies across more than three orders of magnitude in stellar mass from as low as 10⁷M_⊙.

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Harry Teplitz

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