J/ApJ/908/154 SDSS J1723+3411 UV and optical spectra at z=1.3293 (Rigby+, 2021)
A Comparison of Rest-frame Ultraviolet and Optical Emission-line Diagnostics in
the Lensed Galaxy SDSS J1723+3411 at Redshift.
Rigby J.R., Florian M., Acharyya A., Bayliss M., Gladders M.D., Sharon K.,
Brammer G., Momcheva I., LaMassa S., Bian F., Dahle H., Johnson T.,
Kewley L., Murray K., Whitaker K., Wuyts E.
<Astrophys. J., 908, 154 (2021)>
=2021ApJ...908..154R 2021ApJ...908..154R
ADC_Keywords: Galaxies; Spectra, optical; Spectra, ultraviolet
Keywords: Gravitational lensing ; Galaxy evolution ; Atomic spectroscopy ;
Spectroscopy ; Emission line galaxies ; Starburst galaxies ;
Interstellar medium
Abstract:
For the extremely bright lensed galaxy SDSSJ1723+3411 at z=1.3293, we
analyze spatially integrated MMT, Keck, and Hubble Space Telescope
spectra that fully cover the rest-frame wavelength range of
1400-7200Å. We also analyze near-IR spectra from Gemini that cover
Hα for a portion of the lensed arc. We report fluxes for 42
detected emission lines, and upper limits for an additional 22. This
galaxy has extreme emission-line ratios and high equivalent widths
that are characteristic of extreme emission-line galaxies. We compute
strong emission-line diagnostics from both the rest-frame optical and
rest-frame ultraviolet (UV), to constrain physical conditions and test
the spectral diagnostics themselves. We tightly determine the nebular
physical conditions using the most reliable diagnostics, and then
compare to results from other diagnostics. We find disappointing
performance from the UV-only diagnostics: they either are unable to
measure the metallicity or dramatically underestimate it; they
overestimate the pressure; and the UV diagnostic of ionization
parameter has a strong metallicity dependence in this regime. Based on
these results, we suggest that upcoming James Webb Space Telescope
(JWST) spectroscopic surveys of galaxies in the reionization epoch
should invest the additional integration time to capture the optical
[OII] and [OIII] emission lines, and not rely solely on the rest-frame
UV emission lines. We make available the spectra; they represent one
of the highest-quality emission-line spectral atlases of star-forming
galaxies available beyond the local universe, and will aid the
planning of observations with JWST.
Description:
We obtained imaging of SDSSJ1723+3411 with the UVIS and IR channels of
the WFC3 instrument onboard HST through guest observer program #13003
(PI Gladders), which was a large program targeting lensed arcs
selected by SGAS. The filters used were F390W, F775W, F1110W, and
F160W, at depths of 2368s, 2380s, 1112s, and 1112s respectively.
Additional WFC3-IR imagery was also obtained in the F105W and F140W
filters.
We obtained spectra of SDSSJ1723+3411 with the WFC3 instrument
onboard HST, using the IR channel and the G102 and G141 grisms, in
guest observer program #14230 (PI Rigby).
We observed SDSSJ1723+3411 with the Blue Channel spectrograph on the
6.5m MMT Observatory telescope on UT 2014 May 5 beginning at 09:20 UT.
Observing time was granted through the Harvard-Smithsonian Center
for Astrophysics. Science exposures of 2400s and 1200s were taken at
central wavelengths of 4005Å and 4205Å, respectively, with the
spectrograph configured with the 125 wide longslit at a position angle
of 295 east of north, and the 800line/mm grating in first order.
We obtained spectra of SDSSJ1723+3411 using the Echellette
Spectrograph and Imager (ESI) on the Keck II telescope. Observations
were made on UT 2016 August 27 and UT 2016 August 28; observing time
was granted through Australian National University. The echellette
mode and the 1" slit were used for all observations, which provides a
spectral resolution of R∼4000.
We obtained spectra of SDSSJ1723+3411 with the GNIRS on the Gemini
North telescope as part of program GN-2016B-FT-11 (PI Rigby).
Observations were obtained on UT 2016 September 7, using the short
camera, cross-dispersing prism ("SXD" mode), the 03 slit, and the
111lines/mm grating with the central wavelength set to 1.529um. This
setup should provide a spectral resolution of R=5900. The spectra
covered observed wavelengths of 1.46-1.60um, which correspond to
rest-frame wavelengths of 0.627-0.687um.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig7_k.dat 90 8065 *Keck/ESI spectrum of SGAS 1723
fig7_m.dat 90 2982 *MMT Blue Channel spectrum of SGAS J1723
fig7_102.dat 102 196 *HST/WFC-3 G102 grism spectrum of S1723, from
both roll angles
fig7_141.dat 102 163 *ST/WFC-3 G141 grism spectrum of S1723, from both
roll angles
fig7_c.dat 90 7425 *Composite convenience spectrum for lensed galaxy
SDSS J1723+3411 at redshift z=1.3293
fig8.dat 65 359 Combined high-resolution GNIRS spectra for S1723
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Note on fig7*.dat: Milky Way reddening has been corrected
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See also:
J/A+A/448/955 : Abundances of emission galaxies in SDSS-DR3 (Izotov+, 2006)
J/ApJ/795/165 : Line ratios in z∼2-3 galaxies KBSS-MOSFIRE (Steidel+, 2014)
J/ApJ/814/L6 : CIII emission in near & far star-forming galax (Rigby+, 2015)
J/ApJ/822/42 : z∼3.3 star-forming galaxies NIR spectra (Onodera+, 2016)
J/ApJ/817/118 : SFR-M* relation from ZFOURGE (Tomczak+, 2016)
J/AJ/155/104 : MEGaSaURA. I. The sample and the spectra (Rigby+, 2018)
J/A+A/641/A118 : Mean rest-UV spectra of Lya emitters at z>3 (Feltre+, 2020)
J/ApJS/247/12 : Strong lens models for 37 clusters from SGAS (Sharon+, 2020)
Byte-by-byte Description of file: fig7_k.dat fig7_m.dat fig7_c.dat
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Bytes Format Units Label Explanations
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1- 19 F19.13 0.1nm Wave wavelength, vacuum Angstroms
21- 43 A23 10+7W/m3 Flux Flux, f-lambda, erg/s/cm2/A (1)
45- 66 A22 10+7W/m3 e_Flux Flux uncertainty
68- 90 A23 10+7W/m3 Flux-ac Flux continuum fit
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Note (1): Scaled Keck/ESI flux so that sum of [OII] 3727+3729 fluxes matches
flux of those lines in HST/WFC-IR G102. Factor was 0.5727
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Byte-by-byte Description of file: fig7_1*.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 0.1nm Wave Wavelength, vacuum Angstroms
9- 31 A23 10+7W/m3 Flux Flux, f-lambda, erg/s/cm2/A
33- 54 A22 10+7W/m3 e_Flux Flux uncertainty
56- 78 A23 10+7W/m3 Cflux Flux continuum fit
80-102 A23 10+7W/m3 Flux-c Flux minus continuum fit
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Byte-by-byte Description of file: fig8.dat
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Bytes Format Units Label Explanations
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1- 18 F18.12 0.1nm Wave Wavelength, vacuum, barycentric-corrected
Angstroms
20- 42 A23 10+7W/m3 Flux Flux, f-lambda, erg/s/cm2/A (1)
44- 65 A22 10+7W/m3 e_Flux Flux uncertainty
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Note (1): Scaled GNIRS spectrum to match Halpha flux in WFC-IR G141, by factor
5.184170877838979e-18.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 23-Feb-2024