The ALPINE-ALMA [CII] survey: Dust attenuation properties and obscured star formation at z~4.4-5.8
| Autor: | Fudamoto, Yoshinobu, Oesch, P. A., Faisst, A., Bethermin, M., Ginolfi, M., Khusanova, Y., Loiacono, F., Fevre, O. Le, Capak, P., Schaerer, D., Silverman, J. D., Cassata, P., Yan, L., Amorin, R., Bardelli, S., Boquien, M., Cimatti, A., Dessauges-Zavadsky, M., Fujimoto, S., Gruppioni, C., Hathi, N. P., Ibar, E., Jones, G. C., Koekemoer, A. M., Lagache, G., Lemaux, B. C., Maiolino, R., Narayanan, D., Pozzi, F., Riechers, D. A., Rodighiero, G., Talia, M., Toft, S., Vallini, L., Vergani, D., Zamorani, G., Zucca, E. |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | A&A 643, A4 (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202038163 |
| Popis: | We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of ~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_*), 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~4.4-5.8. The individual detections and stacks show that the IRX-$\beta$ relation at z~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 (SMC). This systematic change of the IRX-$\beta$ 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 1dex on average, at a fixed mass compared to previously studied IRX-M_* relations at z<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>4 are characterised by (i) a steeper attenuation curve than at z<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_*/$M_\odot$>10) at z~5-6 already exhibit an obscured fraction of star formation of ~45%, indicating a rapid build-up of dust during the epoch of reionization. Comment: 12 pages, 6 figures. accepted for publication in Astronomy & Astrophysics. Minor revisions |
| Databáze: | arXiv |
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