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Gaia Data Release 3. Specific processing and validation of all-sky RR Lyrae and Cepheid stars: The RR Lyrae sample
DOI: 10.1051/0004-6361/202243964 Bibcode: 2023A&A...674A..18C

Szabados, L.; Audard, M.; Andrae, R. +18 more

Context. RR Lyrae stars are excellent tracers of the oldest stars (ages ≳ 9-10 Gyr) and standard candles for measuring the distance to stellar systems that are mainly composed of an old stellar population. The Gaia Third Data Release (DR3) publishes a catalogue of full-sky RR Lyrae stars observed during the initial 34 months of science operations.…

2023 Astronomy and Astrophysics
Gaia 107
Early Results from GLASS-JWST. XIV. A Spectroscopically Confirmed Protocluster 650 Million Years after the Big Bang
DOI: 10.3847/2041-8213/acb99e Bibcode: 2023ApJ...947L..24M

Santini, Paola; Calabrò, Antonello; Castellano, Marco +39 more

We present the spectroscopic confirmation of a protocluster at z = 7.88 behind the galaxy cluster Abell 2744 (hereafter A2744-z7p9OD). Using JWST NIRSpec, we find seven galaxies within a projected radius of 60 kpc. Although the galaxies reside in an overdensity around ≳20× greater than a random volume, they do not show strong Lyα emission. We plac…

2023 The Astrophysical Journal
JWST 106
Momentum transfer from the DART mission kinetic impact on asteroid Dimorphos
DOI: 10.1038/s41586-023-05878-z Bibcode: 2023Natur.616..457C

Zinzi, Angelo; Cheng, Andrew F.; Dall'Ora, Massimo +66 more

The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on 26 September 2022 as a planetary defence test1. DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planeta…

2023 Nature
eHST 105
Excitation and Ionization Properties of Star-forming Galaxies at z = 2.0-9.3 with JWST/NIRSpec
DOI: 10.3847/1538-4357/acedad Bibcode: 2023ApJ...955...54S

Shapley, Alice E.; Reddy, Naveen A.; Sanders, Ryan L. +2 more

We utilize medium-resolution JWST/NIRSpec observations of 164 galaxies at z = 2.0-9.3 from the Cosmic Evolution Early Release Science (CEERS) survey to investigate the evolution of the excitation and ionization properties of galaxies at high redshifts. Our results represent the first statistical constraints on the evolution of the [O III]/Hβ versu…

2023 The Astrophysical Journal
eHST JWST 105
The MillenniumTNG project: the galaxy population at z ≥ 8
DOI: 10.1093/mnras/stac3743 Bibcode: 2023MNRAS.524.2594K

Springel, Volker; Hernquist, Lars; Pakmor, Rüdiger +11 more

The early release science results from JWST have yielded an unexpected abundance of high-redshift luminous galaxies that seems to be in tension with current theories of galaxy formation. However, it is currently difficult to draw definitive conclusions form these results as the sources have not yet been spectroscopically confirmed. It is in any ca…

2023 Monthly Notices of the Royal Astronomical Society
eHST JWST 104
The Target-selection Pipeline for the Dark Energy Spectroscopic Instrument
DOI: 10.3847/1538-3881/aca5f9 Bibcode: 2023AJ....165...50M

Myers, Adam D.; Bailey, Stephen; Palanque-Delabrouille, Nathalie +51 more

In 2021 May, the Dark Energy Spectroscopic Instrument (DESI) began a 5 yr survey of approximately 50 million total extragalactic and Galactic targets. The primary DESI dark-time targets are emission line galaxies, luminous red galaxies, and quasars. In bright time, DESI will focus on two surveys known as the Bright Galaxy Survey and the Milky Way …

2023 The Astronomical Journal
Gaia 104
A magnified compact galaxy at redshift 9.51 with strong nebular emission lines
DOI: 10.1126/science.adf5307 Bibcode: 2023Sci...380..416W

Koekemoer, Anton M.; Treu, Tommaso; Broadhurst, Tom +21 more

Ultraviolet light from early galaxies is thought to have ionized gas in the intergalactic medium. However, there are few observational constraints on this epoch because of the faintness of those galaxies and the redshift of their optical light into the infrared. We report the observation, in JWST imaging, of a distant galaxy that is magnified by g…

2023 Science
Gaia eHST JWST 103
Nitrogen enhancements 440 Myr after the big bang: supersolar N/O, a tidal disruption event, or a dense stellar cluster in GN-z11?
DOI: 10.1093/mnras/stad1579 Bibcode: 2023MNRAS.523.3516C

Cameron, Alex J.; Saxena, Aayush; Katz, Harley +1 more

Recent observations of GN-z11 with JWST/NIRSpec revealed numerous oxygen, carbon, nitrogen, and helium emission lines at z = 10.6. Using the measured line fluxes, we derive abundance ratios of individual elements within the interstellar medium (ISM) of this superluminous galaxy. Driven by the unusually-bright N III] λ1750 and N IV] λ1486 emission …

2023 Monthly Notices of the Royal Astronomical Society
JWST 103
Star formation histories of UV-luminous galaxies at z ≃ 6.8: implications for stellar mass assembly at early cosmic times
DOI: 10.1093/mnras/stad004 Bibcode: 2023MNRAS.519.5859W

Charlot, Stéphane; Chevallard, Jacopo; Stark, Daniel P. +3 more

The variety of star formation histories (SFHs) of z ≳ 6 galaxies provides important insights into early star formation, but has been difficult to systematically quantify. Some observations suggest that many z ~ 6-9 galaxies are dominated by ≳200 Myr stellar populations, implying significant star formation at z ≳ 9, while others find that most reio…

2023 Monthly Notices of the Royal Astronomical Society
eHST 103
A first look at the SMACS0723 JWST ERO: spectroscopic redshifts, stellar masses, and star-formation histories
DOI: 10.1093/mnrasl/slac136 Bibcode: 2023MNRAS.518L..45C

Cullen, F.; McLure, R. J.; Dunlop, J. S. +9 more

We present a first-look analysis of the JWST ERO data in the SMACS J0723.3-7327 cluster field. We begin by reporting 10 new spectroscopic redshifts from λobs = 1.8-5.2 µm NIRSpec medium-resolution (R = λ/Δλ = 1000) data. These are determined via multiple high-SNR emission line detections with five objects at 1 < z < 3 displa…

2023 Monthly Notices of the Royal Astronomical Society
Gaia eHST JWST 102