Abstract
Observations have revealed unexpectedly large amounts of dust in high-redshift galaxies and its origin is still much debated. Valiante et al. suggested the net stellar dust production of the quasar host galaxy SDSS J1148+5251 may be sufficient to explain the large dust mass detected in this galaxy, albeit under some very special assumptions (e.g. 'closed-box' evolution and a rather high gas mass). Here it is shown that since accretion of essentially pristine material may lower the efficiency of dust formation significantly, and the observationally derived dust-to-gas ratios for these high-redshift galaxies are remarkably high, stellar dust production is likely insufficient. A model including metallicity-dependent, non-stellar dust formation ('secondary dust') is presented. The required contribution from this non-stellar dust component appears too large, however. If all observational constraints are to be met, the resultant dust-to-metals ratio is close to unity, which means that almost all interstellar metals exist in the form of dust. This is a very unlikely situation and suggests the large dust-to-gas ratios at high redshifts may be due to observational uncertainties and/or incorrect calibration of conversion factors for gas and dust tracers.
| Original language | English |
|---|---|
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 441 |
| Issue number | 1 |
| Pages (from-to) | 781-791 |
| ISSN | 0035-8711 |
| DOIs | |
| Publication status | Published - Jun 2011 |