%0 Generic %1 casey2017nearinfrared %A Casey, C. M. %A Cooray, A. %A Killi, M. %A Capak, P. %A Chen, C. C. %A Hung, C. L. %A Kartaltepe, J. %A Sanders, D. B. %A Scoville, N. Z. %D 2017 %K dusty forming galaxies spectra star %T Near-Infrared MOSFIRE Spectra of Dusty Star-Forming Galaxies at 0.2<z<4 %U http://arxiv.org/abs/1703.10168 %X We present near-infrared and optical spectroscopic observations of a sample of 450$\mu$m and 850$\mu$m-selected dusty star-forming galaxies (DSFGs) identified in a 400 arcmin$^2$ area in the COSMOS field. Thirty-one sources of the 102 targets were spectroscopically confirmed at $0.2<z<4$, identified primarily in the near-infrared with Keck MOSFIRE and some in the optical with Keck LRIS and DEIMOS. The low rate of confirmation is attributable both to high rest-frame optical obscuration in our targets and limited sensitivity to certain redshift ranges. The high-quality photometric redshifts available in the COSMOS field allow us to test the robustness of photometric redshifts for DSFGs. We find a subset (11/31$\approx35$%) of DSFGs with inaccurate ($\Delta z/(1+z)>0.2$) or non-existent photometric redshifts; these have very distinct spectral energy distributions from the remaining DSFGs, suggesting a decoupling of highly obscured and unobscured components. We present a composite rest-frame 4300--7300\AA\ spectrum for DSFGs, and find evidence of 200$\pm$30 km s$^-1$ gas outflows. Nebular line emission for a sub-sample of our detections indicate that hard ionizing radiation fields are ubiquitous in high-z DSFGs, even more so than typical mass or UV-selected high-z galaxies. We also confirm the extreme level of dust obscuration in DSFGs, measuring very high Balmer decrements, and very high ratios of IR to UV and IR to H$\alpha$ luminosities. This work demonstrates the need to broaden the use of wide bandwidth technology in the millimeter to the spectroscopic confirmations of large samples of high-z DSFGs, as the difficulty in confirming such sources at optical/near-infrared wavelengths is exceedingly challenging given their obscuration.

@misc{casey2017nearinfrared, abstract = {We present near-infrared and optical spectroscopic observations of a sample of 450$\mu$m and 850$\mu$m-selected dusty star-forming galaxies (DSFGs) identified in a 400 arcmin$^2$ area in the COSMOS field. Thirty-one sources of the 102 targets were spectroscopically confirmed at $0.2<z<4$, identified primarily in the near-infrared with Keck MOSFIRE and some in the optical with Keck LRIS and DEIMOS. The low rate of confirmation is attributable both to high rest-frame optical obscuration in our targets and limited sensitivity to certain redshift ranges. The high-quality photometric redshifts available in the COSMOS field allow us to test the robustness of photometric redshifts for DSFGs. We find a subset (11/31$\approx35$%) of DSFGs with inaccurate ($\Delta z/(1+z)>0.2$) or non-existent photometric redshifts; these have very distinct spectral energy distributions from the remaining DSFGs, suggesting a decoupling of highly obscured and unobscured components. We present a composite rest-frame 4300--7300\AA\ spectrum for DSFGs, and find evidence of 200$\pm$30 km s$^{-1}$ gas outflows. Nebular line emission for a sub-sample of our detections indicate that hard ionizing radiation fields are ubiquitous in high-z DSFGs, even more so than typical mass or UV-selected high-z galaxies. We also confirm the extreme level of dust obscuration in DSFGs, measuring very high Balmer decrements, and very high ratios of IR to UV and IR to H$\alpha$ luminosities. This work demonstrates the need to broaden the use of wide bandwidth technology in the millimeter to the spectroscopic confirmations of large samples of high-z DSFGs, as the difficulty in confirming such sources at optical/near-infrared wavelengths is exceedingly challenging given their obscuration.}, added-at = {2017-03-31T09:57:42.000+0200}, author = {Casey, C. M. and Cooray, A. and Killi, M. and Capak, P. and Chen, C. C. and Hung, C. L. and Kartaltepe, J. and Sanders, D. B. and Scoville, N. Z.}, biburl = {https://www.bibsonomy.org/bibtex/2fae3fde6da951ee244c2f0af1ccc5d17/miki}, description = {[1703.10168] Near-Infrared MOSFIRE Spectra of Dusty Star-Forming Galaxies at 0.2&lt;z&lt;4}, interhash = {af722a9c8d1ea94e012ea120ddce14b6}, intrahash = {fae3fde6da951ee244c2f0af1ccc5d17}, keywords = {dusty forming galaxies spectra star}, note = {cite arxiv:1703.10168Comment: 14 pages, 13 figures, ApJ accepted. Composite DSFG Halpha spectrum available at www.as.utexas.edu/~cmcasey/downloads.html}, timestamp = {2017-03-31T09:57:42.000+0200}, title = {Near-Infrared MOSFIRE Spectra of Dusty Star-Forming Galaxies at 0.2<z<4}, url = {http://arxiv.org/abs/1703.10168}, year = 2017 }