Bibliographic Details
| Title: |
Significant Dust-Obscured Star Formation in Luminous Lyman-break Galaxies at $z$$\sim$$7$$-$$8$ |
| Authors: |
Schouws, Sander, Stefanon, Mauro, Bouwens, Rychard J., Smit, Renske, Hodge, Jacqueline A., Labbé, Ivo, Algera, Hiddo S., Boogaard, Leindert, Carniani, Stefano, Fudamoto, Yoshi, Holwerda, Benne W., Illingworth, Garth D., Maiolino, Roberto, Maseda, Michael V., Oesch, Pascal A., van der Werf, Paul P. |
| Publication Year: |
2021 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies |
| More Details: |
We make use of ALMA continuum observations of $15$ luminous Lyman-break galaxies at $z$$\sim$$7$$-$$8$ to probe their dust-obscured star-formation. These observations are sensitive enough to probe to obscured SFRs of $20$ $M_{\odot}$$/$$yr$ ($3\sigma$). Six of the targeted galaxies show significant ($\geq$$3$$\sigma$) dust continuum detections, more than doubling the number of known dust-detected galaxies at $z$$>$$6.5$. Their IR luminosities range from $2.7$$\times$$10^{11}$ $L_{\odot}$ to $1.1$$\times$$10^{12}$ $L_{\odot}$, equivalent to obscured SFRs of $20$ to $105$ $M_{\odot}$$/$$yr$. We use our results to quantify the correlation of the infrared excess IRX on the UV-continuum slope $\beta_{UV}$ and stellar mass. Our results are most consistent with an SMC attenuation curve for intrinsic $UV$-slopes $\beta_{UV,intr}$ of $-2.63$ and most consistent with an attenuation curve in-between SMC and Calzetti for $\beta_{UV,intr}$ slopes of $-2.23$, assuming a dust temperature $T_d$ of $50$ K. Our fiducial IRX-stellar mass results at $z$$\sim$$7$$-$$8$ are consistent with marginal evolution from $z$$\sim$$0$. We then show how both results depend on $T_d$. For our six dust-detected sources, we estimate their dust masses and find that they are consistent with dust production from SNe if the dust destruction is low ($<$$90$%). Finally we determine the contribution of dust-obscured star formation to the star formation rate density for $UV$ luminous ($<$$-$$21.5$ mag: $\gtrsim$$1.7$$L_{UV} ^*$) $z$$\sim$$7$$-$$8$ galaxies, finding that the total SFR density at $z$$\sim$$7$ and $z$$\sim$$8$ from bright galaxies is $0.18_{-0.10}^{+0.08}$ dex and $0.20_{-0.09}^{+0.05}$ dex higher, respectively, i.e. $\sim$$\frac{1}{3}$ of the star formation in $\gtrsim$$1.7$$L_{UV} ^*$ galaxies at $z$$\sim$$7$$-$$8$ is obscured by dust.
Comment: 21 pages, 12 figures, 2 tables. Submitted to ApJ |
| Document Type: |
Working Paper |
| DOI: |
10.3847/1538-4357/ac4605 |
| Access URL: |
http://arxiv.org/abs/2105.12133 |
| Accession Number: |
edsarx.2105.12133 |
| Database: |
arXiv |
