ABSTRACT
We analyse the chemical properties of three z∼ 8 galaxies behind the galaxy cluster SMACS J0723.3-7327, observed as part of the Early Release Observations programme of the James Webb Space ...Telescope. Exploiting O iiiλ4363 auroral line detections in NIRSpec spectra, we robustly apply the direct Te method for the very first time at such high redshift, measuring metallicities ranging from extremely metal poor (12 + log(O/H)≈ 7) to about one-third solar. We also discuss the excitation properties of these sources, and compare them with local strong-line metallicity calibrations. We find that none of the considered diagnostics match simultaneously the observed relations between metallicity and strong-line ratios for the three sources, implying that a proper re-assessment of the calibrations may be needed at these redshifts. On the mass–metallicity plane, the two galaxies at z ∼ 7.6 ($\rm log(M_*/M_{\odot }) = 8.1, 8.7$) have metallicities that are consistent with the extrapolation of the mass–metallicity relation at z∼2–3, while the least massive galaxy at z ∼ 8.5 ($\rm log(M_*/M_{\odot }) = 7.8$) shows instead a significantly lower metallicity. The three galaxies show different level of offset relative to the Fundamental Metallicity Relation, with two of them (at z∼ 7.6) being marginally consistent, while the z∼ 8.5 source deviating significantly, being probably far from the smooth equilibrium between gas flows, star formation, and metal enrichment in place at later epochs.
We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate
z
> 10 Lyman break galaxy in the GOODS-North field with
M
UV
= −21.5. We derive a redshift of
z
= 10.603 (lower ...than previous determinations) based on multiple emission lines in our low and medium resolution spectra over 0.7 − 5.3 μm. We significantly detect the continuum and measure a blue rest-UV spectral slope of
β
= −2.4. Remarkably, we see spatially extended Lyman-
α
in emission (despite the highly neutral intergalactic medium expected at this early epoch), offset 555 km s
−1
redwards of the systemic redshift. From our measurements of collisionally excited lines of both low and high ionisation (including O
II
λ
3727, Ne
III
λ
3869, and C
III
λ
1909), we infer a high ionisation parameter (log
U
∼ −2). We detect the rarely seen N
IV
λ
1486 and N
III
λ
1748 lines in both our low and medium resolution spectra, with other high ionisation lines seen in the low resolution spectrum, such as He
II
(blended with O
III
) and C
IV
(with a possible P-Cygni profile). Based on the observed rest-UV line ratios, we cannot conclusively rule out photoionisation from an active galactic nucleus (AGN), although the high C
III
/He
II
and N
III
/He
II
ratios are compatible with a star formation explanation. If the observed emission lines are powered by star formation, then the strong N
III
λ
1748 observed may imply an unusually high
N
/
O
abundance. Balmer emission lines (H
γ
, H
δ
) are also detected, and if powered by star formation rather than an AGN, we infer a star formation rate of ∼20 − 30
M
⊙
yr
−1
(depending on the initial mass function) and low dust attenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkable galaxy with extreme properties seen 430 Myr after the Big Bang.
Abstract
JWST has revolutionized the field of extragalactic astronomy with its sensitive and high-resolution infrared view of the distant Universe. Adding to the new legacy of JWST observations, we ...present the first NIRCam imaging data release from the JWST Advanced Deep Extragalactic Survey (JADES), providing nine filters of infrared imaging of ∼25 arcmin
2
covering the Hubble Ultra Deep Field and portions of Great Observatories Origins Deep Survey South. Utilizing 87 on-sky dual-filter hours of exposure time, these images reveal the deepest ever near-infrared view of this iconic field. We supply carefully constructed nine-band mosaics of the JADES bands, as well as matching reductions of five additional bands from the JWST Extragalactic Medium-band Survey. Combining with existing Hubble Space Telescope imaging, we provide 23-band space-based photometric catalogs and photometric redshifts for ≈47,500 sources. To promote broad engagement with JADES, we have created an interactive
FitsMap
website to provide an interface for professional researchers and the public to experience these JWST data sets. Combined with the first JADES NIRSpec data release, these public JADES imaging and spectroscopic data sets provide a new foundation for discoveries of the infrared Universe by the worldwide scientific community.
Extreme emission line galaxies (EELGs) exhibit large equivalent widths (EW) in their rest-optical emission lines (OIII\(\lambda5007\) or H\(\alpha\) rest-frame EW\( > 750Å\)) which can be tied to a ...recent upturn in star formation rate, due to the sensitivity of the nebular line emission and the rest-optical continuum to young (\(<10\)Myr) and evolved stellar populations, respectively. By studying a sample of 85 star forming galaxies (SFGs), spanning the redshift and magnitude interval \(3 <z<9.5\) and \(-16>\) M\(_{UV}>-21\), in the JWST Advanced Deep Extragalactic Survey (JADES) with NIRSpec/prism spectroscopy, we determine that SFGs initiate an EELG phase when entering a significant burst of star formation, with the highest EWs observed in EELGs with the youngest mass-weighted ages (\(<5\) Myr old) and the highest burst intensity (those with the highest proportion of their total stellar mass formed in the last 10 Myr). We spectroscopically confirm that a greater proportion of SFGs are in an EELG phase at high redshift in our UV-selected sample (\(61\pm4\%\) in our \(z>5.7\) high-redshift bin, compared to \(23^{+4}_{-1}\%\) in our lowest-redshift bin \(3<z<4.1\)) due to the combined evolution of metallicity, ionisation parameter and star formation histories (SFH) with redshift. We report that the EELGs within our sample exhibit a higher average ionisation efficiency (\(\log_{10}(\xi_{ion}^{HII}/\)erg\(^{-1}\)Hz)\(=25.5\pm0.2\)) than the non-EELGs. High-redshift EELGs therefore comprise a population of efficient ionising photon producers. Additionally, we report that \(53\%\) (9/17) of EELGs at \(z>5.7\) have observed Lyman-\(\alpha\) emission, potentially lying within large ionised regions. The high detection rate of Lyman-\(\alpha\) emitters in our EELG selection suggests that the physical conditions associated with entering an EELG phase also promote the escape of Lyman-\(\alpha\) photons.
We describe the NIRSpec component of the JWST Deep Extragalactic Survey (JADES), and provide deep spectroscopy of 253 sources targeted with the NIRSpec micro-shutter assembly in the Hubble Ultra Deep ...Field and surrounding GOODS-South. The multi-object spectra presented here are the deepest so far obtained with JWST, amounting to up to 28 hours in the low-dispersion (\(R\sim 30-300\)) prism, and up to 7 hours in each of the three medium-resolution \(R\approx 1000\) gratings and one high-dispersion grating, G395H (\(R\approx2700\)). Our low-dispersion and medium-dispersion spectra cover the wavelength range \(0.6-5.3\mu\)m. We describe the selection of the spectroscopic targets, the strategy for the allocation of targets to micro-shutters, and the design of the observations. We present the public release of the reduced 2D and 1D spectra, and a description of the reduction and calibration process. We measure spectroscopic redshifts for 178 of the objects targeted extending up to \(z=13.2\). We present a catalog of all emission lines detected at \(S/N>5\), and our redshift determinations for the targets. Combined with the first JADES NIRCam data release, these public JADES spectroscopic and imaging datasets provide a new foundation for discoveries of the infrared universe by the worldwide scientific community.
We present an overview of the James Webb Space Telescope (JWST) Advanced Deep Extragalactic Survey (JADES), an ambitious program of infrared imaging and spectroscopy in the GOODS-S and GOODS-N deep ...fields, designed to study galaxy evolution from high redshift to cosmic noon. JADES uses about 770 hours of Cycle 1 guaranteed time largely from the Near-Infrared Camera (NIRCam) and Near-Infrared Spectrograph (NIRSpec) instrument teams. In GOODS-S, in and around the Hubble Ultra Deep Field and Chandra Deep Field South, JADES produces a deep imaging region of ~45 arcmin\(^2\) with an average of 130 hrs of exposure time spread over 9 NIRCam filters. This is extended at medium depth in GOODS-S and GOODS-N with NIRCam imaging of ~175 arcmin\(^2\) with an average exposure time of 20 hrs spread over 8-10 filters. In both fields, we conduct extensive NIRSpec multi-object spectroscopy, including 2 deep pointings of 55 hrs exposure time, 14 medium pointings of ~12 hrs, and 15 shallower pointings of ~4 hrs, targeting over 5000 HST and JWST-detected faint sources with 5 low, medium, and high-resolution dispersers covering 0.6-5.3 microns. Finally, JADES extends redward via coordinated parallels with the JWST Mid-Infrared Instrument (MIRI), featuring ~9 arcmin\(^2\) with 43 hours of exposure at 7.7 microns and twice that area with 2-6.5 hours of exposure at 12.8 microns For nearly 30 years, the GOODS-S and GOODS-N fields have been developed as the premier deep fields on the sky; JADES is now providing a compelling start on the JWST legacy in these fields.
Finding and characterising the first galaxies that illuminated the early Universe at cosmic dawn is pivotal to understand the physical conditions and the processes that led to the formation of the ...first stars. In the first few months of operations, imaging from the James Webb Space Telescope (JWST) have been used to identify tens of candidates of galaxies at redshift (z) greater than 10, less than 450 million years after the Big Bang. However, none of these candidates has yet been confirmed spectroscopically, leaving open the possibility that they are actually low-redshift interlopers. Here we present spectroscopic confirmation and analysis of four galaxies unambiguously detected at redshift 10.3<z<13.2, previously selected from NIRCam imaging. The spectra reveal that these primeval galaxies are extremely metal poor, have masses between 10^7 and a few times 10^8 solar masses, and young ages. The damping wings that shape the continuum close to the Lyman edge are consistent with a fully neutral intergalactic medium at this epoch. These findings demonstrate the rapid emergence of the first generations of galaxies at cosmic dawn.
A&A 677, A88 (2023) We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous
candidate $z>10$ Lyman break galaxy in the GOODS-North field with
$M_{UV}=-21.5$. We derive a redshift of ...$z=10.603$ (lower than previous
determinations) based on multiple emission lines in our low and medium
resolution spectra over $0.8-5.3 \mu$m. We significantly detect the continuum
and measure a blue rest-UV spectral slope of $\beta=-2.4$. Remarkably, we see
spatially-extended Lyman-$\alpha$ in emission (despite the highly-neutral IGM
expected at this early epoch), offset 555 km s$^{-1}$ redward of the systemic
redshift. From our measurements of collisionally-excited lines of both low- and
high-ionization (including O II$\lambda3727$, Ne III$\lambda 3869$ and C
III$\lambda1909$) we infer a high ionization parameter ($\log U\sim -2$). We
detect the rarely-seen N IV$\lambda1486$ and N III$\lambda1748$ lines in both
our low and medium resolution spectra, with other high ionization lines seen in
the low resolution spectrum such as He II (blended with O III) and C IV (with
a possible P-Cygni profile). Based on the observed rest-UV line ratios, we
cannot conclusively rule out photoionization from AGN, although the high C
III/He II and N III/He II ratios are compatible with a star-formation
explanation. If the observed emission lines are powered by star formation, then
the strong N III$\lambda1748$ observed may imply an unusually high $N/O$
abundance. Balmer emission lines (H$\gamma$, H$\delta$) are also detected, and
if powered by star formation rather than an AGN we infer a star formation rate
of $\sim 20-30 M_{\odot} yr^{-1}$ (depending on the IMF) and low dust
attenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkable
galaxy with extreme properties seen 430 Myr after the Big Bang.
We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate \(z>10\) Lyman break galaxy in the GOODS-North field with \(M_{UV}=-21.5\). We derive a redshift of \(z=10.603\) ...(lower than previous determinations) based on multiple emission lines in our low and medium resolution spectra over \(0.8-5.3 \mu\)m. We significantly detect the continuum and measure a blue rest-UV spectral slope of \(\beta=-2.4\). Remarkably, we see spatially-extended Lyman-\(\alpha\) in emission (despite the highly-neutral IGM expected at this early epoch), offset 555 km s\(^{-1}\) redward of the systemic redshift. From our measurements of collisionally-excited lines of both low- and high-ionization (including O II\(\lambda3727\), Ne III\(\lambda 3869\) and C III\(\lambda1909\)) we infer a high ionization parameter (\(\log U\sim -2\)). We detect the rarely-seen N IV\(\lambda1486\) and N III\(\lambda1748\) lines in both our low and medium resolution spectra, with other high ionization lines seen in the low resolution spectrum such as He II (blended with O III) and C IV (with a possible P-Cygni profile). Based on the observed rest-UV line ratios, we cannot conclusively rule out photoionization from AGN, although the high C III/He II and N III/He II ratios are compatible with a star-formation explanation. If the observed emission lines are powered by star formation, then the strong N III\(\lambda1748\) observed may imply an unusually high \(N/O\) abundance. Balmer emission lines (H\(\gamma\), H\(\delta\)) are also detected, and if powered by star formation rather than an AGN we infer a star formation rate of \(\sim 20-30 M_{\odot} yr^{-1}\) (depending on the IMF) and low dust attenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkable galaxy with extreme properties seen 430 Myr after the Big Bang.
