We present the spectroscopic confirmation of the brightest known gravitationally lensed Lyman-break galaxy in the Epoch of Reionization (EoR), A1703-zD1, through the detection of [C ii] 158 $\mu$m at a redshift of z = 6.8269 ± 0.0004. This source was selected behind the strong lensing cluster Abell 1703, with an intrinsic luminosity and a very blue Spitzer/Infrared Array Camera (IRAC) [3.6]–[4.5] colour, implying high equivalent width line emission of [O iii] + Hβ. [C ii] is reliably detected at 6.1σ cospatial with the rest-frame ultraviolet (UV) counterpart, showing similar spatial extent. Correcting for the lensing magnification, the [C ii] luminosity in A1703-zD1 is broadly consistent with the local $L_{\rm [C\, {\small II}]}$–star formation rate (SFR) relation. We find a clear velocity gradient of 103 ± 22 km $\rm s^{-1}$ across the source that possibly indicates rotation or an ongoing merger. We furthermore present spectral scans with no detected [C ii] above 4.6σ in two unlensed Lyman-break galaxies in the Extended Groth Strip (EGS)-Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) field at z ∼ 6.6–6.9. This is the first time that the Northern Extended Millimeter Array (NOEMA) has been successfully used to observe [C ii] in a ‘normal’ star-forming galaxy at z > 6, and our results demonstrate its capability to complement the Atacama Large Millimeter/submillimeter Array (ALMA) in confirming galaxies in the EoR.
We present reduced images and catalogues of photometric and emission-line data (∼230 000 and ∼8000 sources, respectively) for the WFC3 (Wide Field Camera 3) Infrared Spectroscopic Parallel (WISP) survey. These data are made publicly available on the Mikulski Archive for Space Telescopes and include reduced images from various facilities: ground-based ugri, Hubble Space Telescope (HST) WFC3, and Spitzer IRAC (Infrared Array Camera). Coverage in at least one additional filter beyond the WFC3/IR data are available for roughly half of the fields (227 out of 483), with ∼20 per cent (86) having coverage in six or more filters from u band to IRAC 3.6 $\mu$m (0.35–3.6 $\mu$m). For the lower spatial resolution (and shallower) ground-based and IRAC data, we perform PSF (point spread function)-matched, prior-based, deconfusion photometry (i.e. forced-photometry) using the tphot software to optimally extract measurements or upper limits. We present the methodology and software used for the WISP emission-line detection and visual inspection. The former adopts a continuous wavelet transformation that significantly reduces the number of spurious sources as candidates before the visual inspection stage. We combine both WISP catalogues and perform spectral energy distribution fitting on galaxies with reliable spectroscopic redshifts and multiband photometry to measure their stellar masses. We stack WISP spectra as functions of stellar mass and redshift and measure average emission-line fluxes and ratios. We find that WISP emission-line sources are typically ‘normal’ star-forming galaxies based on the mass–excitation diagram ([O iii]/Hβ versus M⋆; 0.74 < zgrism < 2.31), the galaxy main sequence (SFR versus M⋆; 0.30 < zgrism < 1.45), S32 ratio versus M⋆ (0.30 < zgrism < 0.73), and O32 and R23 ratios versus M⋆ (1.27 < zgrism < 1.45).
more » « less- NSF-PAR ID:
- 10499824
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 530
- Issue:
- 1
- ISSN:
- 0035-8711
- Format(s):
- Medium: X Size: p. 894-928
- Size(s):
- ["p. 894-928"]
- Sponsoring Org:
- National Science Foundation
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