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2023
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Astrophysical processes
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1. ChinaXiv:202303.04135
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JADES: Probing interstellar medium conditions at $z\sim5.5-9.5$ with ultra-deep JWST/NIRSpec spectroscopy

Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19

Alex J. Cameron Aayush Saxena Andrew J. Bunker Francesco D'Eugenio Stefano Carniani Roberto Maiolino Emma Curtis-Lake Pierre Ferruit Peter Jakobsen Santiago Arribas Nina Bonaventura Stephane Charlot Jacopo Chevallard Mirko Curti Tobias J. Looser Michael V. Maseda Tim Rawle Bruno Rodríguez Del Pino Renske Smit Hannah Übler

Abstract： We present emission line ratios from a sample of 26 Lyman break galaxies from $z\sim5.5-9.5$ with $-17.05.5$ spectra. We find that the emission line ratios exhibited by these $z\sim5.5-9.5$ galaxies occupy clearly distinct regions of line-ratio space compared to typical z~0-3 galaxies, instead being more consistent with extreme populations of lower-redshift galaxies. This is best illustrated by the [OIII]/[OII] ratio, tracing interstellar medium (ISM) ionisation, in which we observe more than half of our sample to have [OIII]/[OII]>10. Our high signal-to-noise spectra reveal more than an order of magnitude of scatter in line ratios such as [OII]/H$\beta$ and [OIII]/[OII], indicating significant diversity in the ISM conditions within the sample. We find no convincing detections of [NII] in our sample, either in individual galaxies, or a stack of all G395M/F290LP spectra. The emission line ratios observed in our sample are generally consistent with galaxies with extremely high ionisation parameters (log $U\sim-1.5$), and a range of metallicities spanning from $\sim0.1\times Z_\odot$ to higher than $\sim0.3\times Z_\odot$, suggesting we are probing low-metallicity systems undergoing periods of rapid star-formation, driving strong radiation fields. These results highlight the value of deep observations in constraining the properties of individual galaxies, and hence probing diversity within galaxy population.

Peer Review Status:Awaiting Review

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2. ChinaXiv:202303.06122
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The ALPINE-ALMA [CII] survey: The infrared-radio correlation and AGN fraction of star-forming galaxies at z $\sim$ 4.4-5.9

Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19

Lu Shen Brian C. Lemaux Lori M. Lubin Guilin Liu Matthieu Béthermin Médéric Boquien Olga Cucciati Olivier Le Fèvre Margherita Talia Daniela Vergani Gianni Zamorani Andreas L. Faisst Michele Ginolfi Carlotta Gruppioni Gareth C. Jones Sandro Bardelli Nimish Hathi Anton M. Koekemoer Michael Romano Daniel Schaerer

Abstract： We present the radio properties of 66 spectroscopically-confirmed normal star-forming galaxies (SFGs) at $4.4展开 -->

Peer Review Status:Awaiting Review

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3. ChinaXiv:202303.03351
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JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy

Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19

Andrew J. Bunker Aayush Saxena Alex J. Cameron Chris J. Willott Emma Curtis-Lake Peter Jakobsen Stefano Carniani Renske Smit Roberto Maiolino Joris Witstok Mirko Curti Francesco D'Eugenio Gareth C. Jones Pierre Ferruit Santiago Arribas Stephane Charlot Jacopo Chevallard Giovanna Giardino Anna de Graaff Tobias J. Looser

Abstract： 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 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 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. The high C III]/He II ratios, however, suggest a likely 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 $\sim 20-30 M_{\odot}\,\rm yr^{-1}$ (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.

Peer Review Status:Awaiting Review

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4. ChinaXiv:202303.07639
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JADES: Discovery of extremely high equivalent width Lyman-alpha emission from a faint galaxy within an ionized bubble at z=7.3

Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19

Aayush Saxena Brant E. Robertson Andrew J. Bunker Ryan Endsley Alex J. Cameron Stephane Charlot Charlotte Simmonds Sandro Tacchella Joris Witstok Chris Willott Stefano Carniani Emma Curtis-Lake Pierre Ferruit Peter Jakobsen Santiago Arribas Jacopo Chevallard Mirko Curti Francesco D'Eugenio Anna De Graaff Gareth C. Jones

Abstract： We report the discovery of a remarkable Ly$\alpha$ emitting galaxy at $z=7.278$, JADES-GS+53.16746-27.7720 (shortened to JADES-GS-z7-LA), with EW$_0$(Ly$\alpha$) $\approx400 \pm 90$A and UV magnitude $-16.7$. The spectroscopic redshift is confirmed via rest-frame optical lines [O II], H$\beta$ and [O III] in its JWST/NIRSpec Micro-Shutter Assembly (MSA) spectrum. The Ly$\alpha$ line is detected in both lower resolution ($R\sim100$) PRISM as well as medium resolution ($R\sim1000$) G140M grating spectra. The Ly$\alpha$ FWHM in the grating is $\approx360$ km s$^{-1}$ and the line peaks within $120$ km s$^{-1}$ of the systemic redshift, indicative of very little neutral gas or dust within the galaxy. We estimate the Ly$\alpha$ escape fraction to be $\sim100\%$. JADES-GS-z7-LA has a [O III]/[O II] ratio (O32) of $8.8 \pm 1.1$ and ([O III]+[O II])/H$\beta$ ratio (R23) of $9.6\pm2.2$, consistent with low metallicity and high ionization parameters. Deep NIRCam imaging also revealed a close companion source (separated by $0.23''$), which exhibits similar photometry to that of JADES-GS-z7-LA, with a photometric excess in the F410M NIRCam image consistent with [O III]+H$\beta$ emission at the same redshift. The spectral energy distribution of JADES-GS-z7-LA indicates a `bursty' star-formation history, with a low stellar mass of $10^{7.15}$ M$_\odot$. The only explanation of the high EW Ly$\alpha$ emission seen in JADES-GS-z7-LA is if it resides in an ionized bubble with radius $\gtrsim 3$ pMpc. Owing to the faint nature of JADES-GS-z7-LA, we show that it is incapable of single-handedly ionizing a bubble large enough. Therefore, we suggest that JADES-GS-z7-LA (and possibly the companion source) may be a part of a larger overdensity, presenting direct evidence of overlapping ionized bubbles at $z>7$, allowing us to study the process of reionization across both small and large scales.

Peer Review Status:Awaiting Review

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5. ChinaXiv:202303.07704
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Spectroscopic confirmation of four metal-poor galaxies at z=10.3-13.2

Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19

Emma Curtis-Lake Stefano Carniani Alex Cameron Stephane Charlot Peter Jakobsen Roberto Maiolino Andrew Bunker Joris Witstok Renske Smit Jacopo Chevallard Chris Willott Pierre Ferruit Santiago Arribas Nina Bonaventura Mirko Curti Francesco D'Eugenio Marijn Franx Giovanna Giardino Tobias J. Looser Nora Lützgendorf

Abstract： 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展开 -->

Peer Review Status:Awaiting Review

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JADES: Probing interstellar medium conditions at $z\sim5.5-9.5$ with ultra-deep JWST/NIRSpec spectroscopy

The ALPINE-ALMA [CII] survey: The infrared-radio correlation and AGN fraction of star-forming galaxies at z $\sim$ 4.4-5.9

JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy

JADES: Discovery of extremely high equivalent width Lyman-alpha emission from a faint galaxy within an ionized bubble at z=7.3

Spectroscopic confirmation of four metal-poor galaxies at z=10.3-13.2