TY - JOUR

T1 - A3COSMOS

T2 - the dust attenuation of star-forming galaxies at z=2.5-4.0 from the COSMOS-ALMA archive

AU - Fudamoto, Yoshinobu

AU - Oesch, P. A.

AU - Magnelli, B.

AU - Schinnerer, E.

AU - Liu, D.

AU - Lang, P.

AU - Jimenez-Andrade, E. E.

AU - Groves, B.

AU - Leslie, S.

AU - Sargent, M. T.

PY - 2020/2

Y1 - 2020/2

N2 - We present an analysis of the dust attenuation of star-forming galaxies at z = 2.5-4.0 through the relationship between the UV spectral slope (beta), stellar mass (M-*), and the infrared excess (IRX = L-IR/L-UV) based on far-infrared continuum observations from the Atacama Large Millimeter/sub-millimeter Array (ALMA). Our study exploits the full ALMA archive over the COSMOS field processed by the A3COSMOS team, which includes an unprecedented sample of similar to 1500 galaxies at z similar to 3 as primary or secondary targets in ALMA band 6 or 7 observations with a median continuum sensitivity of 126 mu Jy beam(-1) (1 sigma). The detection rate is highly mass dependent, decreasing drastically below log (M-*/M-circle dot) = 10.5. The detected galaxies show that the IRX-beta relationship of massive (logM(*)/M-circle dot > 10) main-sequence galaxies at z = 2.5-4.0 is consistent with that of local galaxies, while starbursts are generally offset by similar to 0.5 dex to larger IRX values. At the low-mass end, we derive upper limits on the infrared luminosities through stacking of the ALMA data. The combined IRX-M-* relation at log (M-*/M-circle dot) > 9 exhibits a significantly steeper slope than reported in previous studies at similar redshifts, implying little dust obscuration at logM(*)/M-circle dot <10. However, our results are consistent with earlier measurements at z similar to 5.5, indicating a potential redshift evolution between z similar to 2 and z similar to 6. Deeper observations targeting low-mass galaxies will be required to confirm this finding.

AB - We present an analysis of the dust attenuation of star-forming galaxies at z = 2.5-4.0 through the relationship between the UV spectral slope (beta), stellar mass (M-*), and the infrared excess (IRX = L-IR/L-UV) based on far-infrared continuum observations from the Atacama Large Millimeter/sub-millimeter Array (ALMA). Our study exploits the full ALMA archive over the COSMOS field processed by the A3COSMOS team, which includes an unprecedented sample of similar to 1500 galaxies at z similar to 3 as primary or secondary targets in ALMA band 6 or 7 observations with a median continuum sensitivity of 126 mu Jy beam(-1) (1 sigma). The detection rate is highly mass dependent, decreasing drastically below log (M-*/M-circle dot) = 10.5. The detected galaxies show that the IRX-beta relationship of massive (logM(*)/M-circle dot > 10) main-sequence galaxies at z = 2.5-4.0 is consistent with that of local galaxies, while starbursts are generally offset by similar to 0.5 dex to larger IRX values. At the low-mass end, we derive upper limits on the infrared luminosities through stacking of the ALMA data. The combined IRX-M-* relation at log (M-*/M-circle dot) > 9 exhibits a significantly steeper slope than reported in previous studies at similar redshifts, implying little dust obscuration at logM(*)/M-circle dot <10. However, our results are consistent with earlier measurements at z similar to 5.5, indicating a potential redshift evolution between z similar to 2 and z similar to 6. Deeper observations targeting low-mass galaxies will be required to confirm this finding.

KW - galaxies: evolution

KW - galaxies: ISM

KW - galaxies: star formation

KW - submillimetre: ISM

KW - ULTRAVIOLET LUMINOSITY DENSITY

KW - HIGH-REDSHIFT

KW - FORMATION HISTORY

KW - STELLAR MASS

KW - TO 3

KW - OBSCURATION

KW - CALIBRATION

KW - POPULATION

KW - EXTINCTION

KW - EVOLUTION

U2 - 10.1093/mnras/stz3248

DO - 10.1093/mnras/stz3248

M3 - Journal article

VL - 491

SP - 4724

EP - 4734

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 4

ER -