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EVOLUTION OF INTRINSIC SCATTER IN THE SFR-STELLAR MASS CORRELATION AT 0.5 < <i>z</i> < 3
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, American Astronomical Society 2016 ASTROPHYSICAL JOURNAL LETTERS - Vol.820 No.1
<P>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(11)M(circle dot). 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, 5 sigma depth) probes the SFR-M-* correlation down to M-* similar to 10(7)M(circle dot), a factor of 10-100x 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 similar to 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 10(7)M(circle dot).</P>
CANDELS Sheds Light on the Environmental Quenching of Low-mass Galaxies
Guo, Yicheng,Bell, Eric F.,Lu, Yu,Koo, David C.,Faber, S. M.,Koekemoer, Anton M.,Kurczynski, Peter,Lee, Seong-Kook,Papovich, Casey,Chen, Zhu,Dekel, Avishai,Ferguson, Henry C.,Fontana, Adriano,Giavalis American Astronomical Society 2017 ASTROPHYSICAL JOURNAL LETTERS - Vol.841 No.2
<P>We investigate the environmental quenching of galaxies, especially those with stellar masses (M-*) < 10(9.5) Me-circle dot, beyond the local universe. Essentially all local low-mass quenched galaxies (QGs) are believed to live close to massive central galaxies, which is a demonstration of environmental quenching. We use CANDELS data to test whether or not such a dwarf QG-massive central galaxy connection exists beyond the local universe. For this purpose, we only need a statistically representative, rather than complete, sample of low-mass galaxies, which enables our study to z greater than or similar to 1.5. For each low-mass galaxy, we measure the projected distance (d(proj)) to its nearest massive neighbor (M-* > 10(10.5) M-circle dot) within a redshift range. At a given z and M-*, the environmental quenching effect is considered to be observed if the d(proj) distribution of QGs (d(proj)(Q)) is significantly skewed toward lower values than that of star-forming galaxies (d(proj)(SF)). For galaxies with 10(8) M-circle dot < M-* < 10(10) M-circle dot, such a difference between d(proj)(Q) and d(proj)(SF) is detected up to z similar to 1. Also, about 10% of the quenched galaxies in our sample are located between two and four virial radii (R-Vir) of the massive halos. The median projected distance from low-mass QGs to their massive neighbors, d(proj)(Q)/R-Vir, decreases with satellite M-* at M-* less than or similar to 10(9.5) M-circle dot, but increases with satellite M-* at M-* greater than or similar to 10(9.5) M-circle dot. This trend suggests a smooth, if any, transition of the quenching timescale around M-* similar to 10(9.5) M-circle dot at 0.5 < z < 1.0.</P>