%0 Generic %1 citeulike:14290436 %A Khoperskov, Sergey A. %A Vasiliev, Evgenii O. %D 2017 %K imported %T A Kennicutt-Schmidt relation at molecular cloud scales and beyond %U http://arxiv.org/abs/1702.08562 %X Using N-body/gasdynamic simulations of a Milky Way-like galaxy we analyse a Kennicutt-Schmidt relation, \$\Sigma\_SFR \Sigma\_gas^N\$, at different spatial scales. We simulate synthetic observations in CO lines and UV band. We adopt the star formation rate defined in two ways: based on free fall collapse of a molecular cloud - \$\Sigma\_SFR, cl\$, and calculated by using a UV flux calibration - \$\Sigma\_SFR, UV\$. We study a KS relation for spatially smoothed maps with effective spatial resolution from molecular cloud scales to several hundred parsecs. We find that for spatially and kinematically resolved molecular clouds the \$\Sigma\_SFR, cl \Sigma\_gas^N\$ relation follows the power-law with index \$N 1.4\$. Using UV flux as SFR calibrator we confirm a systematic offset between the \$\Sigma\_UV\$ and \$\Sigma\_gas\$ distributions on scales compared to molecular cloud sizes. Degrading resolution of our simulated maps for surface densities of gas and star formation rates we establish that there is no relation \$\Sigma\_SFR, UV - \Sigma\_gas\$ below the resolution \$50\$ pc. We find a transition range around scales \$50-120\$ pc, where the power-law index \$N\$ increases from 0 to 1-1.8 and saturates for scales larger \$120\$ pc. A value of the index saturated depends on a surface gas density threshold and it becomes steeper for higher \$\Sigma\_gas\$ threshold. Averaging over scales with size of \$>150\$ pc the power-law index \$N\$ equals 1.3-1.4 for surface gas density threshold \$5 M\_ødot\$pc\$^-2\$. At scales \$>120\$ pc surface SFR densities determined by using CO data and UV flux, \$\Sigma\_SFR, UV/\Sigma\_SFR, cl\$, demonstrate a discrepancy about a factor of 3. We argue that this may be originated from overestimating (constant) values of conversion factor, star formation efficiency or UV calibration used in our analysis.

@misc{citeulike:14290436, abstract = {Using N-body/gasdynamic simulations of a Milky Way-like galaxy we analyse a Kennicutt-Schmidt relation, \$\Sigma\_{SFR} \propto \Sigma\_{gas}^N\$, at different spatial scales. We simulate synthetic observations in CO lines and UV band. We adopt the star formation rate defined in two ways: based on free fall collapse of a molecular cloud - \$\Sigma\_{SFR, cl}\$, and calculated by using a UV flux calibration - \$\Sigma\_{SFR, UV}\$. We study a KS relation for spatially smoothed maps with effective spatial resolution from molecular cloud scales to several hundred parsecs. We find that for spatially and kinematically resolved molecular clouds the \$\Sigma\_{SFR, cl} \propto \Sigma\_{\rm gas}^N\$ relation follows the power-law with index \$N \approx 1.4\$. Using UV flux as SFR calibrator we confirm a systematic offset between the \$\Sigma\_{\rm UV}\$ and \$\Sigma\_{\rm gas}\$ distributions on scales compared to molecular cloud sizes. Degrading resolution of our simulated maps for surface densities of gas and star formation rates we establish that there is no relation \$\Sigma\_{\rm SFR, UV} - \Sigma\_{\rm gas}\$ below the resolution \$\sim 50\$ pc. We find a transition range around scales \$\sim 50-120\$ pc, where the power-law index \$N\$ increases from 0 to 1-1.8 and saturates for scales larger \$\sim 120\$ pc. A value of the index saturated depends on a surface gas density threshold and it becomes steeper for higher \$\Sigma\_{gas}\$ threshold. Averaging over scales with size of \$\>150\$ pc the power-law index \$N\$ equals 1.3-1.4 for surface gas density threshold \$\sim 5 M\_\odot\$pc\$^{-2}\$. At scales \$\>120\$ pc surface SFR densities determined by using CO data and UV flux, \$\Sigma\_{\rm SFR, UV}/\Sigma\_{\rm SFR, cl}\$, demonstrate a discrepancy about a factor of 3. We argue that this may be originated from overestimating (constant) values of conversion factor, star formation efficiency or UV calibration used in our analysis.}, added-at = {2019-03-25T08:20:55.000+0100}, archiveprefix = {arXiv}, author = {Khoperskov, Sergey A. and Vasiliev, Evgenii O.}, biburl = {https://www.bibsonomy.org/bibtex/23a21cd38b7f6039c2e7fcd241287d425/ericblackman}, citeulike-article-id = {14290436}, citeulike-linkout-0 = {http://arxiv.org/abs/1702.08562}, citeulike-linkout-1 = {http://arxiv.org/pdf/1702.08562}, day = 27, eprint = {1702.08562}, interhash = {2d90ce4b9e9d4f3f4217bc4d94c57b71}, intrahash = {3a21cd38b7f6039c2e7fcd241287d425}, keywords = {imported}, month = feb, posted-at = {2017-03-05 22:14:29}, priority = {2}, timestamp = {2019-03-25T08:20:55.000+0100}, title = {{A Kennicutt-Schmidt relation at molecular cloud scales and beyond}}, url = {http://arxiv.org/abs/1702.08562}, year = 2017 }