Dust masses of $z>5$ galaxies from SED fitting and ALMA upper limits

Hiroyuki Hirashita; Denis Burgarella; Rychard J. Bouwens

doi:10.1093/mnras/stx2349

paper

Dust masses of $z > 5$ galaxies from SED fitting and ALMA upper limits

arXiv:1709.02526 · doi:10.1093/mnras/stx2349

Abstract

We aim at constraining the dust mass in high-redshift ( $z ≳ 5$ ) galaxies using the upper limits obtained by ALMA in combination with the rest-frame UV--optical spectral energy distributions (SEDs). For SED fitting, because of degeneracy between dust extinction and stellar age, we focus on two extremes: continuous star formation (Model A) and instantaneous star formation (Model B). We apply these models to Himiko (as a representative UV-bright object) and a composite SED of $z > 5$ Lyman break galaxies (LBGs). For Himiko, Model A requires a significant dust extinction, which leads to a high dust temperature $> 70$ K for consistency with the ALMA upper limit. This high dust temperature puts a strong upper limit on the total dust mass $M_{d} ≲ 2 \times 1 0^{6}$ M $_{⊙}$ , and the dust mass produced per supernova (SN) $m_{d, SN} ≲ 0.1$ M $_{⊙}$ . Such a low $m_{d, SN}$ suggests significant loss of dust by reverse shock destruction or outflow, and implies that SNe are not the dominant source of dust at high $z$ . Model B allows $M_{d} \sim 2 \times 1 0^{7}$ M $_{⊙}$ and $m_{d, SN} \sim 0.3$ M $_{⊙}$ .} We could distinguish between Models A and B if we observe Himiko at {wavelength $<$ 1.2 mm by ALMA. For the LBG sample, we obtain $M_{d} ≲ 2 \times 1 0^{6}$ M $_{⊙}$ for a typical LBG at $z > 5$ , but this only puts an upper limit for $m_{d, SN}$ as $\sim 2$ M $_{⊙}$ . This clarifies the importance of observing UV-bright objects (like Himiko) to constrain the dust production by SNe.

arXiv comment12 pages, 6 figures, accepted for publication in MNRAS

Dust masses of $z > 5$ galaxies from SED fitting and ALMA upper limits

Abstract

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Dust masses of z>5 galaxies from SED fitting and ALMA upper limits

Abstract

References in corpus (73)

Cited by in corpus (12)

Dust masses of $z > 5$ galaxies from SED fitting and ALMA upper limits