TY - JOUR

T1 - The ALPINE-ALMA [CII] survey

T2 - Dust attenuation properties and obscured star formation at z similar to 4.4-5.8

AU - Fudamoto, Y.

AU - Oesch, P. A.

AU - Faisst, A.

AU - Bethermin, M.

AU - Ginolfi, M.

AU - Khusanova, Y.

AU - Loiacono, F.

AU - Le Fevre, O.

AU - Capak, P.

AU - Schaerer, D.

AU - Silverman, J. D.

AU - Cassata, P.

AU - Yan, L.

AU - Amorin, R.

AU - Bardelli, S.

AU - Boquien, M.

AU - Cimatti, A.

AU - Dessauges-Zavadsky, M.

AU - Fujimoto, S.

AU - Gruppioni, C.

AU - Hathi, N. P.

AU - Ibar, E.

AU - Jones, G. C.

AU - Koekemoer, A. M.

AU - Lagache, G.

AU - Lemaux, B. C.

AU - Maiolino, R.

AU - Narayanan, D.

AU - Pozzi, F.

AU - Riechers, D. A.

AU - Rodighiero, G.

AU - Talia, M.

AU - Toft, S.

AU - Vallini, L.

AU - Vergani, D.

AU - Zamorani, G.

AU - Zucca, E.

PY - 2020/10/27

Y1 - 2020/10/27

N2 - We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of similar to 4.4-5.8. Our analyses are based on the far infrared continuum observations of 118 galaxies at rest-frame 158 mu m obtained with the Atacama Large Millimeter Array (ALMA) Large Program to INvestigate [CII] at Early times (ALPINE). We study the connection between the ultraviolet (UV) spectral slope (beta), stellar mass (M-star), and infrared excess (IRX = L-IR/L-UV). Twenty-three galaxies are individually detected in the continuum at > 3.5 sigma significance. We perform a stacking analysis using both detections and nondetections to study the average dust attenuation properties at z similar to 4.4-5.8. The individual detections and stacks show that the IRX-beta relation at z similar to 5 is consistent with a steeper dust attenuation curve than typically found at lower redshifts (z<4). The attenuation curve is similar to or even steeper than that of the extinction curve of the Small Magellanic Cloud. This systematic change of the IRX- relation as a function of redshift suggests an evolution of dust attenuation properties at z> 4. Similarly, we find that our galaxies have lower IRX values, up to 1 dex on average, at a fixed mass compared to previously studied IRX-M-star relations at z less than or similar to 4, albeit with significant scatter. This implies a lower obscured fraction of star formation than at lower redshifts. Our results suggest that dust properties of UV-selected star forming galaxies at z greater than or similar to 4 are characterised by (i) a steeper attenuation curve than at z less than or similar to 4, and (ii) a rapidly decreasing dust obscured fraction of star formation as a function of redshift. Nevertheless, even among this UV-selected sample, massive galaxies (log M-star/M-circle dot> 10) at z similar to 5-6 already exhibit an obscured fraction of star formation of similar to 45%, indicating a rapid build-up of dust during the epoch of reionization.

AB - We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of similar to 4.4-5.8. Our analyses are based on the far infrared continuum observations of 118 galaxies at rest-frame 158 mu m obtained with the Atacama Large Millimeter Array (ALMA) Large Program to INvestigate [CII] at Early times (ALPINE). We study the connection between the ultraviolet (UV) spectral slope (beta), stellar mass (M-star), and infrared excess (IRX = L-IR/L-UV). Twenty-three galaxies are individually detected in the continuum at > 3.5 sigma significance. We perform a stacking analysis using both detections and nondetections to study the average dust attenuation properties at z similar to 4.4-5.8. The individual detections and stacks show that the IRX-beta relation at z similar to 5 is consistent with a steeper dust attenuation curve than typically found at lower redshifts (z<4). The attenuation curve is similar to or even steeper than that of the extinction curve of the Small Magellanic Cloud. This systematic change of the IRX- relation as a function of redshift suggests an evolution of dust attenuation properties at z> 4. Similarly, we find that our galaxies have lower IRX values, up to 1 dex on average, at a fixed mass compared to previously studied IRX-M-star relations at z less than or similar to 4, albeit with significant scatter. This implies a lower obscured fraction of star formation than at lower redshifts. Our results suggest that dust properties of UV-selected star forming galaxies at z greater than or similar to 4 are characterised by (i) a steeper attenuation curve than at z less than or similar to 4, and (ii) a rapidly decreasing dust obscured fraction of star formation as a function of redshift. Nevertheless, even among this UV-selected sample, massive galaxies (log M-star/M-circle dot> 10) at z similar to 5-6 already exhibit an obscured fraction of star formation of similar to 45%, indicating a rapid build-up of dust during the epoch of reionization.

KW - galaxies: high-redshift

KW - galaxies: ISM

KW - dust

KW - extinction

KW - HIGH-REDSHIFT

KW - FORMING GALAXIES

KW - LEGACY SURVEY

KW - STELLAR MASS

KW - ULTRAVIOLET

KW - POPULATION

KW - EXTINCTION

KW - FIELD

KW - CALIBRATION

KW - EVOLUTION

U2 - 10.1051/0004-6361/202038163

DO - 10.1051/0004-6361/202038163

M3 - Journal article

VL - 643

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

SN - 0004-6361

M1 - A4

ER -