%0 Generic %1 crighton2015possible %A Crighton, Neil H. M. %A O'Meara, John M. %A Murphy, Michael T. %D 2015 %K lls low metallicity popIII %T Possible Population III Remnants at Redshift 3.5 %U http://arxiv.org/abs/1512.00477 %X The first stars, known as Population III (PopIII), produced the first heavy elements, thereby enriching their surrounding pristine gas. Previous detections of metals in intergalactic gas clouds, however, find a heavy element enrichment larger than $1/1000$ times that of the solar environment, higher than expected for PopIII remnants. In this letter we report the discovery of a Lyman limit system (LLS) at $z=3.53$ with the lowest metallicity seen in gas with discernable metals, $10^-3.41\pm0.26$ times the solar value, at a level expected for PopIII remnants. We make the first relative abundance measurement in such low metallicity gas: the carbon-to-silicon ratio is $10^-0.26\pm0.17$ times the solar value. This is consistent with models of gas enrichment by a PopIII star formation event early in the Universe, but also consistent with later, Population II enrichment. The metals in all three components comprising the LLS, which has a velocity width of 400 km s$^-1$, are offset in velocity by $\sim+6$ km s$^-1$ from the bulk of the hydrogen, suggesting the LLS was enriched by a single event. Relative abundance measurements in this near-pristine regime open a new avenue for testing models of early gas enrichment and metal mixing.

@misc{crighton2015possible, abstract = {The first stars, known as Population III (PopIII), produced the first heavy elements, thereby enriching their surrounding pristine gas. Previous detections of metals in intergalactic gas clouds, however, find a heavy element enrichment larger than $1/1000$ times that of the solar environment, higher than expected for PopIII remnants. In this letter we report the discovery of a Lyman limit system (LLS) at $z=3.53$ with the lowest metallicity seen in gas with discernable metals, $10^{-3.41\pm0.26}$ times the solar value, at a level expected for PopIII remnants. We make the first relative abundance measurement in such low metallicity gas: the carbon-to-silicon ratio is $10^{-0.26\pm0.17}$ times the solar value. This is consistent with models of gas enrichment by a PopIII star formation event early in the Universe, but also consistent with later, Population II enrichment. The metals in all three components comprising the LLS, which has a velocity width of 400 km s$^{-1}$, are offset in velocity by $\sim+6$ km s$^{-1}$ from the bulk of the hydrogen, suggesting the LLS was enriched by a single event. Relative abundance measurements in this near-pristine regime open a new avenue for testing models of early gas enrichment and metal mixing.}, added-at = {2015-12-03T12:28:23.000+0100}, author = {Crighton, Neil H. M. and O'Meara, John M. and Murphy, Michael T.}, biburl = {https://www.bibsonomy.org/bibtex/2dbdf365c0eccd662166c320094b4a6fe/miki}, description = {[1512.00477] Possible Population III Remnants at Redshift 3.5}, interhash = {93dc6587cb7d86c1676a7b0338d2e12f}, intrahash = {dbdf365c0eccd662166c320094b4a6fe}, keywords = {lls low metallicity popIII}, note = {cite arxiv:1512.00477Comment: To appear in MNRAS letters. Comments welcome}, timestamp = {2015-12-03T12:28:23.000+0100}, title = {Possible Population III Remnants at Redshift 3.5}, url = {http://arxiv.org/abs/1512.00477}, year = 2015 }