%0 Generic %1 Riechers2011 %A Riechers, Dominik A. %A Hodge, Jacqueline %A Walter, Fabian %A Carilli, Christopher L. %A Bertoldi, Frank %D 2011 %K CO cold gas high-z observation submm %T Extended Cold Molecular Gas Reservoirs in z~3.4 Submillimeter Galaxies %U http://arxiv.org/abs/1105.4177 %X We report the detection of spatially resolved CO(1-0) emission in the z~3.4 submillimeter galaxies (SMGs) SMM J09431+4700 and SMM J13120+4242, using the Expanded Very Large Array (EVLA). SMM J09431+4700 is resolved into the two previously reported millimeter sources H6 and H7, separated by ~30kpc in projection. We derive CO(1-0) line luminosities of L'(CO 1-0) = (2.49+/-0.86) and (5.82+/-1.22) x 10^10 K km/s pc^2 for H6 and H7, and L'(CO 1-0) = (23.4+/-4.1) x 10^10 K km/s pc^2 for SMM J13120+4242. These are ~1.5-4.5x higher than what is expected from simple excitation modeling of higher-J CO lines, suggesting the presence of copious amounts of low-excitation gas. This is supported by the finding that the CO(1-0) line in SMM J13120+4242, the system with lowest CO excitation, appears to have a broader profile and more extended spatial structure than seen in higher-J CO lines (which is less prominently seen in SMM J09431+4700). Based on L'(CO 1-0) and excitation modeling, we find M_gas = 2.0-4.3 and 4.7-12.7 x 10^10 Msun for H6 and H7, and M_gas = 18.7-69.4 x 10^10 Msun for SMM J13120+4242. The observed CO(1-0) properties are consistent with the picture that SMM J09431+4700 represents an early-stage, gas-rich major merger, and that SMM J13120+4242 represents such a system in an advanced stage. This study thus highlights the importance of spatially and dynamically resolved CO(1-0) observations of SMGs to further understand the gas physics that drive star formation in these distant galaxies, which becomes possible only now that the EVLA rises to its full capabilities.

@misc{Riechers2011, abstract = { We report the detection of spatially resolved CO(1-0) emission in the z~3.4 submillimeter galaxies (SMGs) SMM J09431+4700 and SMM J13120+4242, using the Expanded Very Large Array (EVLA). SMM J09431+4700 is resolved into the two previously reported millimeter sources H6 and H7, separated by ~30kpc in projection. We derive CO(1-0) line luminosities of L'(CO 1-0) = (2.49+/-0.86) and (5.82+/-1.22) x 10^10 K km/s pc^2 for H6 and H7, and L'(CO 1-0) = (23.4+/-4.1) x 10^10 K km/s pc^2 for SMM J13120+4242. These are ~1.5-4.5x higher than what is expected from simple excitation modeling of higher-J CO lines, suggesting the presence of copious amounts of low-excitation gas. This is supported by the finding that the CO(1-0) line in SMM J13120+4242, the system with lowest CO excitation, appears to have a broader profile and more extended spatial structure than seen in higher-J CO lines (which is less prominently seen in SMM J09431+4700). Based on L'(CO 1-0) and excitation modeling, we find M_gas = 2.0-4.3 and 4.7-12.7 x 10^10 Msun for H6 and H7, and M_gas = 18.7-69.4 x 10^10 Msun for SMM J13120+4242. The observed CO(1-0) properties are consistent with the picture that SMM J09431+4700 represents an early-stage, gas-rich major merger, and that SMM J13120+4242 represents such a system in an advanced stage. This study thus highlights the importance of spatially and dynamically resolved CO(1-0) observations of SMGs to further understand the gas physics that drive star formation in these distant galaxies, which becomes possible only now that the EVLA rises to its full capabilities. }, added-at = {2011-05-24T16:57:18.000+0200}, author = {Riechers, Dominik A. and Hodge, Jacqueline and Walter, Fabian and Carilli, Christopher L. and Bertoldi, Frank}, biburl = {https://www.bibsonomy.org/bibtex/2d9665b88477b4f0e51c59cf4a7be6471/miki}, description = {[1105.4177] Extended Cold Molecular Gas Reservoirs in z~3.4 Submillimeter Galaxies}, interhash = {0ee3c50d8c8017a5f8caad3c8ad58733}, intrahash = {d9665b88477b4f0e51c59cf4a7be6471}, keywords = {CO cold gas high-z observation submm}, note = {cite arxiv:1105.4177 Comment: 6 pages, 4 figures, to appear in ApJL (EVLA Special Issue; accepted May 19, 2011)}, timestamp = {2011-05-24T16:57:18.000+0200}, title = {Extended Cold Molecular Gas Reservoirs in z~3.4 Submillimeter Galaxies}, url = {http://arxiv.org/abs/1105.4177}, year = 2011 }