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Title: THE TEAM KECK REDSHIFT SURVEY 2: MOSFIRE SPECTROSCOPY OF THE GOODS-NORTH FIELD

Abstract

We present the Team Keck Redshift Survey 2 (TKRS2), a near-infrared spectral observing program targeting selected galaxies within the CANDELS subsection of the GOODS-North Field. The TKRS2 program exploits the unique capabilities of the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE), which entered service on the Keck I telescope in 2012 and contributes substantially to the study of galaxy spectral features at redshifts inaccessible to optical spectrographs. The TKRS2 project targets 97 galaxies drawn from samples that include z ≈ 2 emission-line galaxies with features observable in the JHK bands as well as lower-redshift targets with features in the Y band. We present a detailed measurement of MOSFIRE’s sensitivity as a function of wavelength, including the effects of telluric features across the YJHK filters. The largest utility of our survey is in providing rest-frame-optical emission lines for z > 1 galaxies, and we demonstrate that the ratios of strong, optical emission lines of z ≈ 2 galaxies suggest the presence of either higher N/O abundances than are found in z ≈ 0 galaxies or low-metallicity gas ionized by an active galactic nucleus. We have released all TKRS2 data products into the public domain to allow researchers access to representative raw andmore » reduced MOSFIRE spectra.« less

Authors:
; ; ; ; ;  [1]; ; ; ; ; ;  [2]
  1. W. M. Keck Observatory, 65-1120 Mamalahoa Hwy, Kamuela, HI 96743 (United States)
  2. University of California Observatories, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
Publication Date:
OSTI Identifier:
22520098
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 150; Journal Issue: 5; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ELEMENT ABUNDANCE; EMISSION SPECTRA; EMISSION SPECTROSCOPY; GALAXIES; GALAXY NUCLEI; METALLICITY; NITROGEN; OXYGEN; RED SHIFT; SENSITIVITY; TELESCOPES

Citation Formats

Wirth, Gregory D., Kassis, Marc, Lyke, Jim, Rizzi, Luca, Campbell, Randy, Goodrich, Robert W., Trump, Jonathan R., Barro, Guillermo, Guo, Yicheng, Koo, David C., Liu, Fengshan, and Faber, S. M., E-mail: gregory.wirth@gmail.com. THE TEAM KECK REDSHIFT SURVEY 2: MOSFIRE SPECTROSCOPY OF THE GOODS-NORTH FIELD. United States: N. p., 2015. Web. doi:10.1088/0004-6256/150/5/153.
Wirth, Gregory D., Kassis, Marc, Lyke, Jim, Rizzi, Luca, Campbell, Randy, Goodrich, Robert W., Trump, Jonathan R., Barro, Guillermo, Guo, Yicheng, Koo, David C., Liu, Fengshan, & Faber, S. M., E-mail: gregory.wirth@gmail.com. THE TEAM KECK REDSHIFT SURVEY 2: MOSFIRE SPECTROSCOPY OF THE GOODS-NORTH FIELD. United States. doi:10.1088/0004-6256/150/5/153.
Wirth, Gregory D., Kassis, Marc, Lyke, Jim, Rizzi, Luca, Campbell, Randy, Goodrich, Robert W., Trump, Jonathan R., Barro, Guillermo, Guo, Yicheng, Koo, David C., Liu, Fengshan, and Faber, S. M., E-mail: gregory.wirth@gmail.com. Sun . "THE TEAM KECK REDSHIFT SURVEY 2: MOSFIRE SPECTROSCOPY OF THE GOODS-NORTH FIELD". United States. doi:10.1088/0004-6256/150/5/153.
@article{osti_22520098,
title = {THE TEAM KECK REDSHIFT SURVEY 2: MOSFIRE SPECTROSCOPY OF THE GOODS-NORTH FIELD},
author = {Wirth, Gregory D. and Kassis, Marc and Lyke, Jim and Rizzi, Luca and Campbell, Randy and Goodrich, Robert W. and Trump, Jonathan R. and Barro, Guillermo and Guo, Yicheng and Koo, David C. and Liu, Fengshan and Faber, S. M., E-mail: gregory.wirth@gmail.com},
abstractNote = {We present the Team Keck Redshift Survey 2 (TKRS2), a near-infrared spectral observing program targeting selected galaxies within the CANDELS subsection of the GOODS-North Field. The TKRS2 program exploits the unique capabilities of the Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE), which entered service on the Keck I telescope in 2012 and contributes substantially to the study of galaxy spectral features at redshifts inaccessible to optical spectrographs. The TKRS2 project targets 97 galaxies drawn from samples that include z ≈ 2 emission-line galaxies with features observable in the JHK bands as well as lower-redshift targets with features in the Y band. We present a detailed measurement of MOSFIRE’s sensitivity as a function of wavelength, including the effects of telluric features across the YJHK filters. The largest utility of our survey is in providing rest-frame-optical emission lines for z > 1 galaxies, and we demonstrate that the ratios of strong, optical emission lines of z ≈ 2 galaxies suggest the presence of either higher N/O abundances than are found in z ≈ 0 galaxies or low-metallicity gas ionized by an active galactic nucleus. We have released all TKRS2 data products into the public domain to allow researchers access to representative raw and reduced MOSFIRE spectra.},
doi = {10.1088/0004-6256/150/5/153},
journal = {Astronomical Journal (Online)},
number = 5,
volume = 150,
place = {United States},
year = {Sun Nov 15 00:00:00 EST 2015},
month = {Sun Nov 15 00:00:00 EST 2015}
}
  • We present the results of spectroscopic observations in the GOODS-N field completed using DEIMOS on the Keck II telescope as part of the DEEP3 Galaxy Redshift Survey. Observations of 370 unique targets down to a limiting magnitude of R {sub AB} = 24.4 yielded 156 secure redshifts. In addition to redshift information, we provide sky-subtracted one- and two-dimensional spectra of each target. Observations were conducted following the procedures of the Team Keck Redshift Survey (TKRS), thereby producing spectra that augment the TKRS sample while maintaining the uniformity of its spectral database.
  • We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift 2 ≤ z ≤ 2.5 with star formation rates of SFR ∼ 100 M {sub ☉} yr{sup –1} and masses of log(M/M {sub ☉}) ∼10.8. Their high integrated gas velocity dispersions of σ{sub int} =230{sub −30}{sup +40} km s{sup –1}, as measured from emission lines of Hα and [O III], and the resultant M {sub *}-σ{sub int} relation and M {sub *}-M {sub dyn} all match well to those of compact quiescent galaxies at z ∼ 2, as measured from stellar absorption lines.more » Since log(M {sub *}/M {sub dyn}) =–0.06 ± 0.2 dex, these compact SFGs appear to be dynamically relaxed and evolved, i.e., depleted in gas and dark matter (<13{sub −13}{sup +17}%), and present larger σ{sub int} than their non-compact SFG counterparts at the same epoch. Without infusion of external gas, depletion timescales are short, less than ∼300 Myr. This discovery adds another link to our new dynamical chain of evidence that compact SFGs at z ≳ 2 are already losing gas to become the immediate progenitors of compact quiescent galaxies by z ∼ 2.« less
  • We report the results of deep (4.6 hr) H-band spectroscopy of the well studied z {approx} 12 H-band dropout galaxy candidate UDFj-39546284 with MOSFIRE on Keck-I. These data reach a sensitivity of 5-10 Multiplication-Sign 10{sup -19} erg s{sup -1} cm{sup -2} per 4.4 A resolution element between sky lines. Previous papers have argued that this source could either be a large equivalent width line emitting galaxy at 2 < z < 3.5 or a luminous galaxy at z {approx} 12. We find a 2.2{sigma} peak associated with a line candidate in deep Hubble Space Telescope Wide-Field Camera 3 Infrared grismmore » observations, but at a lower flux than expected. After considering several possibilities, we conclude these data cannot conclusively confirm or reject the previous line detection, and significantly deeper spectroscopic observations are required. We also search for low-redshift emission lines in 10 other 7 < z < 10 z, Y, and J-dropout candidates in our mask and find no significant detections.« less
  • As part of the DEEP2 galaxy redshift survey, we analyze absorption line strengths in stacked Keck/DEIMOS spectra of red field galaxies with weak to no emission lines, at redshifts 0.7 {approx}< z {approx}< 1. Comparison with models of stellar population synthesis shows that red galaxies at z {approx} 0:9 have mean luminosity-weighted ages of the order of only 1 Gyr and at least solar metallicities. These ages cannot be reconciled with a scenario where all stars evolved passively after forming at very high z. Rather, a significant fraction of stars can be no more than 1 Gyr old, which meansmore » that some star formation in the stacked populations continued to at least z {approx} 1:2. Furthermore, a comparison of these distant galaxies with a local SDSS sample, using stellar populations synthesis models, shows that the drop in the equivalent width of H{delta} from z {approx} 0:9 to 0.1 is less than predicted by passively evolving models. This admits of two interpretations: either each individual galaxy experiences continuing low-level star formation, or the red-sequence galaxy population from z {approx} 0:9 to 0.1 is continually being added to by new galaxies with younger stars.« less
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