Search Publications

Possible Hycean conditions in the sub-Neptune TOI-270 d
DOI: 10.1051/0004-6361/202348238 Bibcode: 2024A&A...683L...2H

Madhusudhan, Nikku; Holmberg, Måns

The JWST has ushered in a new era in atmospheric characterisations of temperate low-mass exoplanets with recent detections of carbon-bearing molecules in the candidate Hycean world K2-18 b. We investigated JWST observations of the TOI-270 system, with two sub-Neptunes simultaneously transiting the nearby M dwarf during the visit. We report our atm…

2024 Astronomy and Astrophysics
eHST JWST 49
The more the merrier: SRG/eROSITA discovers two further galaxies showing X-ray quasi-periodic eruptions
DOI: 10.1051/0004-6361/202348881 Bibcode: 2024A&A...684A..64A

Gromadzki, M.; Salvato, M.; Liu, Z. +20 more

X-ray quasi-periodic eruptions (QPEs) are a novel addition to the group of extragalactic transients. With only a select number of known sources, and many more models published trying to explain them, we are so far limited in our understanding by small number statistics. In this work, we report the discovery of two further galaxies showing QPEs, he…

2024 Astronomy and Astrophysics
Gaia XMM-Newton 48
PDRs4All: III. JWST's NIR spectroscopic view of the Orion Bar
DOI: 10.1051/0004-6361/202348244 Bibcode: 2024A&A...685A..74P

Hartigan, Patrick; Zhang, Yong; Gordon, Karl D. +135 more

Context. JWST has taken the sharpest and most sensitive infrared (IR) spectral imaging observations ever of the Orion Bar photodis-sociation region (PDR), which is part of the nearest massive star-forming region the Orion Nebula, and often considered to be the 'prototypical' strongly illuminated PDR. Aims. We investigate the impact of radiative fe…

2024 Astronomy and Astrophysics
JWST 48
The Pristine survey: XXIII. Data Release 1 and an all-sky metallicity catalogue based on Gaia DR3 BP/RP spectro-photometry
DOI: 10.1051/0004-6361/202347633 Bibcode: 2024A&A...692A.115M

Fouesneau, Morgan; Sestito, Federico; McConnachie, Alan W. +38 more

We used the spectro-photometric information of ∼219 million stars from Gaia's Data Release 3 (DR3) to calculate synthetic, narrowband, metallicity-sensitive CaHK magnitudes that mimic the observations of the Pristine survey, a survey of photometric metallicities of Milky Way stars that has been mapping more than 6500 deg2 of the norther…

2024 Astronomy and Astrophysics
Gaia 47
GN-z11: The environment of an active galactic nucleus at z = 10.603. New insights into the most distant Lyα detection
DOI: 10.1051/0004-6361/202347187 Bibcode: 2024A&A...687A.283S

Charlot, Stéphane; Carniani, Stefano; Übler, Hannah +23 more

Recent observations with the James Webb Space Telescope (JWST) have further refined the spectroscopic redshift of GN-z11, one of the most distant galaxies identified with the Hubble Space Telescope, at z = 10.603. The presence of extremely dense gas (> 1010 cm−3), the detection of high-ionisation lines and of CII*1335 emis…

2024 Astronomy and Astrophysics
JWST 46
GA-NIFS: The core of an extremely massive protocluster at the epoch of reionisation probed with JWST/NIRSpec
DOI: 10.1051/0004-6361/202348824 Bibcode: 2024A&A...688A.146A

Pérez-González, Pablo G.; Charlot, Stéphane; Chevallard, Jacopo +24 more

Context. The SPT0311-58 system resides in a massive dark-matter halo at z ∼ 6.9. It hosts two dusty galaxies (E and W) with a combined star formation rate (SFR) of ∼3500 M yr−1, mostly obscured and identified by the rest-frame IR emission. The surrounding field exhibits an overdensity of submillimetre sources, making it a ca…

2024 Astronomy and Astrophysics
Gaia eHST JWST 44
Identification of a transition from stochastic to secular star formation around z = 9 with JWST
DOI: 10.1051/0004-6361/202348091 Bibcode: 2024A&A...686A.128C

Magnelli, B.; Daddi, E.; Elbaz, D. +6 more

Star formation histories (SFHs) of early galaxies (6 < z < 12) have been found to be highly stochastic in both simulations and observations, while at z≲6 the presence of a main sequence (MS) of star-forming galaxies implies secular processes at play. In this work we characterise the SFH variability of early galaxies as a function of their st…

2024 Astronomy and Astrophysics
JWST 43
New insight on the nature of cosmic reionizers from the CEERS survey
DOI: 10.1051/0004-6361/202347884 Bibcode: 2024A&A...685A...3M

Kartaltepe, J. S.; Dickinson, M.; Finkelstein, S. L. +30 more

The Epoch of Reionization (EoR) began when galaxies grew in abundance and luminosity, so their escaping Lyman continuum (LyC) radiation started ionizing the surrounding neutral intergalactic medium (IGM). Despite significant recent progress, the nature and role of cosmic reionizers are still unclear: in order to define them, it would be necessary …

2024 Astronomy and Astrophysics
eHST JWST 42
Peering into cosmic reionization: Lyα visibility evolution from galaxies at z = 4.5-8.5 with JWST
DOI: 10.1051/0004-6361/202449644 Bibcode: 2024A&A...688A.106N

Hu, W.; Kartaltepe, J. S.; Dickinson, M. +30 more

The resonant scattering interaction between Lyα photons and neutral hydrogen implies that a partially neutral intergalactic medium has the ability to significantly impact the detectability of Lyα emission in galaxies. Thus, the redshift evolution of the Lyα equivalent width distribution of galaxies offers a key observational probe of the degree of…

2024 Astronomy and Astrophysics
eHST JWST 40
Discovery of a new N-emitter in the epoch of reionization
DOI: 10.1051/0004-6361/202450721 Bibcode: 2024A&A...687L..11S

Schaerer, D.; Marques-Chaves, R.; Xiao, M. +1 more

We report the discovery of a compact star-forming galaxy at z = 9.380 in the GOODS-North field (named GN-z9p4), which shows numerous strong UV-optical emission lines and a single UV line, N IV] λ1486. This makes GN-z9p4 the third-highest redshift N-emitter known to date. We determined the nebular abundances of H, C, N, O and Ne, along with the siz…

2024 Astronomy and Astrophysics
JWST 36