%0 Generic %1 dasilva2014stochastically %A da Silva, Robert L. %A Fumagalli, Michele %A Krumholz, Mark R. %D 2014 %K galaxies indicator myown sfr stochastic %T SLUG - Stochastically Lighting Up Galaxies. II: Quantifying the Effects of Stochasticity on Star Formation Rate Indicators %U http://arxiv.org/abs/1403.4605 %X The integrated light of a stellar population, measured through photometric filters that are sensitive to the presence of young stars, is often used to infer the star formation rate (SFR) for that population. However, these techniques rely on an assumption that star formation is a continuous process, whereas in reality stars form in discrete spatially- and temporally-correlated structures. This discreteness causes the light output to undergo significant time-dependent fluctuations, which, if not accounted for, introduce errors and biases in the inferred SFRs. We use SLUG (a code that Stochastically Lights Up Galaxies) to simulate galaxies undergoing stochastic star formation. We then use these simulations to present a quantitative analysis of these effects and provide tools for calculating probability distribution functions of SFRs given a set of observations. We show that, depending on the SFR tracer used, stochastic fluctuations can produce non-trivial errors at SFRs as high as 1 Msun/yr, and we suggest methods by which future analyses that rely on integrated-light SFR indicators can properly account for stochastic effects. We emphasize that due to the stochastic behavior of blue tracers of SFR, one cannot assign a deterministic single value to the SFR of an individual galaxy.

@misc{dasilva2014stochastically, abstract = {The integrated light of a stellar population, measured through photometric filters that are sensitive to the presence of young stars, is often used to infer the star formation rate (SFR) for that population. However, these techniques rely on an assumption that star formation is a continuous process, whereas in reality stars form in discrete spatially- and temporally-correlated structures. This discreteness causes the light output to undergo significant time-dependent fluctuations, which, if not accounted for, introduce errors and biases in the inferred SFRs. We use SLUG (a code that Stochastically Lights Up Galaxies) to simulate galaxies undergoing stochastic star formation. We then use these simulations to present a quantitative analysis of these effects and provide tools for calculating probability distribution functions of SFRs given a set of observations. We show that, depending on the SFR tracer used, stochastic fluctuations can produce non-trivial errors at SFRs as high as 1 Msun/yr, and we suggest methods by which future analyses that rely on integrated-light SFR indicators can properly account for stochastic effects. We emphasize that due to the stochastic behavior of blue tracers of SFR, one cannot assign a deterministic single value to the SFR of an individual galaxy.}, added-at = {2014-03-20T09:57:44.000+0100}, author = {da Silva, Robert L. and Fumagalli, Michele and Krumholz, Mark R.}, biburl = {https://www.bibsonomy.org/bibtex/22cdc65b8768e222994ca4e198c9b9ffa/miki}, description = {[1403.4605] SLUG - Stochastically Lighting Up Galaxies. II: Quantifying the Effects of Stochasticity on Star Formation Rate Indicators}, interhash = {fe75bf570201d23b3e62b3d5d5596af2}, intrahash = {2cdc65b8768e222994ca4e198c9b9ffa}, keywords = {galaxies indicator myown sfr stochastic}, note = {cite arxiv:1403.4605Comment: 13 pages, 8 figures. Submitted to MNRAS. Comments are welcome}, timestamp = {2014-03-20T09:57:44.000+0100}, title = {SLUG - Stochastically Lighting Up Galaxies. II: Quantifying the Effects of Stochasticity on Star Formation Rate Indicators}, url = {http://arxiv.org/abs/1403.4605}, year = 2014 }