%0 Generic %1 lapham2017herschel %A Lapham, Ryen Carl %A Young, Lisa M. %A Crocker, Alison %D 2017 %K ETG IR atomic spectroscopy %T Herschel Spectroscopy of Early Type Galaxies %U http://arxiv.org/abs/1705.00653 %X We present Herschel spectroscopy of atomic lines arising in photodissociation regions as well as ionization regions of nearby early-type galaxies (ETGs), focusing on the volume-limited Atlas3D sample. Our data include the CII, OI, and NII 122 and 205 micron lines, along with ancillary data including CO and HI maps. We find ETGs have CII/FIR ratios slightly lower than spiral galaxies in the KINGFISH sample, and several ETGs have unusually large NII 122/CII ratios. The NII 122/CII ratio is correlated with UV colors and there is a strong anti-correlation of CII/FIR with NUV-K seen in both spirals and ETGs, likely due to a softer radiation field with fewer photons available to ionize carbon and heat the gas. The correlation thus makes a CII deficit in galaxies with redder stellar populations. The high NII 122/CII (and low CII/FIR) line ratios could also be affected by the removal of much of the diffuse, low density gas, which is consistent with the low HI/H2 ratios. CII is now being used as a star formation indicator, and we find it is just as good for ETGs as in spirals. The CII/CO ratios found are also similar to those found in spiral galaxies. Through use of the NII 205 micron line, estimates of the percentage of CII emission arising from ionized gas indicate a significant portion could arise in ionized regions.

@misc{lapham2017herschel, abstract = {We present Herschel spectroscopy of atomic lines arising in photodissociation regions as well as ionization regions of nearby early-type galaxies (ETGs), focusing on the volume-limited Atlas3D sample. Our data include the [CII], [OI], and [NII] 122 and 205 micron lines, along with ancillary data including CO and HI maps. We find ETGs have [CII]/FIR ratios slightly lower than spiral galaxies in the KINGFISH sample, and several ETGs have unusually large [NII] 122/[CII] ratios. The [NII] 122/[CII] ratio is correlated with UV colors and there is a strong anti-correlation of [CII]/FIR with NUV-K seen in both spirals and ETGs, likely due to a softer radiation field with fewer photons available to ionize carbon and heat the gas. The correlation thus makes a [CII] deficit in galaxies with redder stellar populations. The high [NII] 122/[CII] (and low [CII]/FIR) line ratios could also be affected by the removal of much of the diffuse, low density gas, which is consistent with the low HI/H2 ratios. [CII] is now being used as a star formation indicator, and we find it is just as good for ETGs as in spirals. The [CII]/CO ratios found are also similar to those found in spiral galaxies. Through use of the [NII] 205 micron line, estimates of the percentage of [CII] emission arising from ionized gas indicate a significant portion could arise in ionized regions.}, added-at = {2017-05-03T12:56:24.000+0200}, author = {Lapham, Ryen Carl and Young, Lisa M. and Crocker, Alison}, biburl = {https://www.bibsonomy.org/bibtex/2d381fc4e1df8c87dc54122ab74c1502a/miki}, description = {[1705.00653] Herschel Spectroscopy of Early Type Galaxies}, interhash = {efdabff99c291a45b4c8233ee878abe0}, intrahash = {d381fc4e1df8c87dc54122ab74c1502a}, keywords = {ETG IR atomic spectroscopy}, note = {cite arxiv:1705.00653Comment: This paper has been accepted to ApJ. The paper should be 24 pages and contains 16 figures}, timestamp = {2017-05-03T12:56:24.000+0200}, title = {Herschel Spectroscopy of Early Type Galaxies}, url = {http://arxiv.org/abs/1705.00653}, year = 2017 }