J/ApJ/908/154 Complete sp. for the lensed galaxy SDSS J1723+3411 (Rigby+, 2021) ================================================================================ A comparison of rest-frame ultraviolet and optical emission-line diagnostics in the lensed galaxy SDSS J1723+3411 at redshift z=1.3293. 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. =2021ApJ...908..154R ================================================================================ ADC_Keywords: Galaxies; Spectra, optical; Ultraviolet; Spectra, infrared; Gravitational lensing 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 1400-7200{AA}. We also analyze near-IR spectra from Gemini that cover H{alpha} 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: In this paper, for the bright gravitationally lensed giant arc SDSS_J1723+3411 at z=1.3293 (Figure 1), we analyze spectra from instruments on four telescopes: the Blue Channel spectrograph on the MMT, the Echellette Spectrograph and Imager (ESI) on the Keck II telescope, the WFC3-IR G102 and G141 grisms onboard the Hubble Space Telescope (HST), and the Gemini Near-Infrared Spectrograph (GNIRS) on the Gemini North telescope. All but the Gemini/GNIRS spectra are spatially integrated over the giant arc; the Gemini/GNIRS spectrum covers a small portion of the arc. See Figure 2. 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). 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 through guest observer program #14230 (PI Rigby). 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). Eight orbits of grism spectroscopy were obtained on UT dates 2016-Jan-18, 2016-Jan-19, 2016-Jul-11, and 2016-Jul-14. The total integration times were 2.76hr in each of the G102 and G141 grisms. See Section 2.3.2. 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 4005{AA} and 4205{AA}, respectively. See Section 2.3.3. 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. See Section 2.3.4. 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. The effective integration time was 2970s. See Section 2.3.5. All spectra were corrected for foreground reddening from the Milky Way galaxy, using the value of E(B-V)=0.03415 measured by Green+ (2015ApJ...810...25G). All spectra have had the barycentric correction applied, and all wavelengths are listed in vacuum. Rest wavelengths are from NIST. We use a solar oxygen abundance of 12+log(O/H)=8.72 (Asplund+ 2009ARA&A..47..481A). Objects: ------------------------------------------------------------------------- RA (ICRS) DE Designation(s) ------------------------------------------------------------------------- 17 23 36.49 +34 11 55.8 SGAS 1723 = [SAB2013] SDSS J1723+3411 source ------------------------------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file fig7keck.dat 90 8065 *Keck/ESI spectrum of SGAS 1723 fig7mmt.dat 90 2982 *MMT Blue Channel spectrum of SGAS J1723 fig7g102.dat 102 196 *HST/WFC-3 G102 grism spectrum of S1723, from both roll angles fig7g141.dat 102 163 *HST/WFC-3 G141 grism spectrum of S1723, from both roll angles fig7comp.dat 90 7425 *Composite convenience spectrum for SDSS J1723+3411 (comprised of portions of the MMT, ESI, and WFC3 spectra) fig8.dat 65 359 Combined high-resolution GNIRS spectra for S1723 -------------------------------------------------------------------------------- Note on fig7*.dat: Milky Way reddening has been corrected. The composite convenience spectrum ignores spectral overlap, picks one spectrum for each wavelength, as follows: MMT Blue Channel 3200--4750{AA}; Keck ESI 4750--8500{AA}; HST/WFC-IR G102 grism 8500--11000{AA}; HST/WFC-IR G141 grism 11000--16250{AA} -------------------------------------------------------------------------------- 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[kmc]*.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 19 F19.13 0.1nm lambda [3000.8/16233] Wavelength (vacuum) in Angstroms 21- 43 E23.18 cW/m2/nm Flux ?=0 Flux (f-lambda) in erg/s/cm2/{AA} (1) 45- 66 E22.17 cW/m2/nm e_Flux ?=0 Flux uncertainty 68- 90 E23.18 cW/m2/nm CFlux ? Flux continuum fit (not for composite spectrum) -------------------------------------------------------------------------------- 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 Scaled MMT flux so that sum of CIII in MMT matches sum of those lines in ESI, after ESI scaled to HST/WFC-IR G102. Factor was 1.3382. -------------------------------------------------------------------------------- Byte-by-byte Description of file: fig7g*.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 7 F7.1 0.1nm lambda [7475/17613] Wavelength (vacuum) in Angstroms 9- 31 E23.18 cW/m2/nm Flux ?=0 Flux (f-lambda) in erg/s/cm2/{AA} 33- 54 E22.17 cW/m2/nm e_Flux ?=0 Flux uncertainty 56- 78 E23.18 cW/m2/nm CFlux Flux continuum fit 80-102 E23.18 cW/m2/nm Flux-c Flux minus continuum fit ------------------------------------------------------------------------------- Byte-by-byte Description of file: fig8.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 18 F18.12 0.1nm lambda [15000.85/15499.83] Wavelength (vacuum) barycentric-corrected in Angstroms 20- 42 E23.18 cW/m2/nm Flux [-4.1e-17/4.9e-16] Flux (f-lambda) in erg/s/cm2/{AA} (1) 44- 65 E22.17 cW/m2/nm e_Flux [3.9e-18/1.1e-16] Flux uncertainty -------------------------------------------------------------------------------- Note (1): Scaled GNIRS spectrum to match Halpha flux in WFC-IR G141, by factor 5.184170877838979e-18. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Coralie Fix [CDS], 23-Feb-2024