Explore the vast range of titles available.

The detection of the accelerated expansion of the Universe has been one of the major breakthroughs in modern cosmology. Several cosmological probes (Cosmic Microwave Background, Supernovae Type Ia, Baryon Acoustic Oscillations) have been studied in depth to better understand the nature of the mechanism driving this acceleration, and they are being currently pushed to their limits, obtaining remarkable constraints that allowed us to shape the standard cosmological model. In parallel to that, however, the percent precision achieved has recently revealed apparent tensions between measurements obtained from different methods. These are either indicating some unaccounted systematic effects, or are pointing toward new physics. Following the development of CMB, SNe, and BAO cosmology, it is critical to extend our selection of cosmological probes. Novel probes can be exploited to validate results, control or mitigate systematic effects, and, most importantly, to increase the accuracy and robustness of our results. This review is meant to provide a state-of-art benchmark of the latest advances in emerging “beyond-standard” cosmological probes. We present how several different methods can become a key resource for observational cosmology. In particular, we review cosmic chronometers, quasars, gamma-ray bursts, standard sirens, lensing time-delay with galaxies and clusters, cosmic voids, neutral hydrogen intensity mapping, surface brightness fluctuations, stellar ages of the oldest objects, secular redshift drift, and clustering of standard candles. The review describes the method, systematics, and results of each probe in a homogeneous way, giving the reader a clear picture of the available innovative methods that have been introduced in recent years and how to apply them. The review also discusses the potential synergies and complementarities between the various probes, exploring how they will contribute to the future of modern cosmology.

When the Universe was just 3 billion years old, half of the most massive galaxies had already ceased star formation, and such a galaxy has now been observed using gravitational lensing, unexpectedly turning out to be a compact, fast-spinning disk galaxy rather than a proto-bulge galaxy. Dead disk galaxy formed by incoming gas When the Universe was only three billion years old, half of the most massive galaxies were already 'dead', meaning that few new stars would form in them. It is believed that these galaxies grew into the massive local elliptical galaxies seen today. Sune Toft et al . report an analysis of a galaxy that has been strongly gravitationally lensed. This means that they can observe spatial scales that are far smaller than those accessible by any other means. They find that, surprisingly, the galaxy is a fast-spinning disk and that its stars formed in situ rather than in a nuclear starburst. They conclude that the gas out of which the stars formed was accreted from outside the galaxy in cold streams of gas. At redshift z  = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation 1 , 2 , 3 , 4 . It is believed that they were formed in intense nuclear starbursts and that they ultimately grew into the most massive local elliptical galaxies seen today, through mergers with minor companions 5 , 6 , but validating this picture requires higher-resolution observations of their centres than is currently possible. Magnification from gravitational lensing offers an opportunity to resolve the inner regions of galaxies 7 . Here we report an analysis of the stellar populations and kinematics of a lensed z  = 2.1478 compact galaxy, which—surprisingly—turns out to be a fast-spinning, rotationally supported disk galaxy. Its stars must have formed in a disk, rather than in a merger-driven nuclear starburst 8 . The galaxy was probably fed by streams of cold gas, which were able to penetrate the hot halo gas until they were cut off by shock heating from the dark matter halo 9 . This result confirms previous indirect indications 10 , 11 , 12 , 13 that the first galaxies to cease star formation must have gone through major changes not just in their structure, but also in their kinematics, to evolve into present-day elliptical galaxies.

In the first billion years after the Big Bang, sources of ultraviolet (UV) photons are believed to have ionized intergalactic hydrogen, rendering the Universe transparent to UV radiation. Galaxies brighter than the characteristic luminosity L * (refs.  1 , 2 ) do not provide enough ionizing photons to drive this cosmic reionization. Fainter galaxies are thought to dominate the photon budget; however, they are surrounded by neutral gas that prevents the escape of the Lyman-α photons, which has been the dominant way to identify them so far. JD1 was previously identified as a triply-imaged galaxy with a magnification factor of 13 provided by the foreground cluster Abell 2744 (ref. 3 ), and a photometric redshift of z  ≈ 10. Here we report the spectroscopic confirmation of this very low luminosity (≈0.05  L *) galaxy at z  = 9.79, observed 480 Myr after the Big Bang, by means of the identification of the Lyman break and redward continuum, as well as multiple ≳4 σ emission lines, with the Near-InfraRed Spectrograph (NIRSpec) and Near-InfraRed Camera (NIRCam) instruments. The combination of the James Webb Space Telescope (JWST) and gravitational lensing shows that this ultra-faint galaxy ( M UV  = −17.35)—with a luminosity typical of the sources responsible for cosmic reionization—has a compact (≈150 pc) and complex morphology, low stellar mass (10 7.19   M ⊙ ) and subsolar (≈0.6  Z ⊙ ) gas-phase metallicity. The JWST, with the aid of gravitational lensing, confirms the extreme distance of an ultra-faint galaxy at a redshift of 9.79, showing it to have a luminosity typical of the sources responsible for cosmic reionization and highly compact and complex morphology.

Gravitationally magnified images of a faint galaxy from only 500 million years after the Big Bang suggest that galaxies of that age may be the dominant source of the radiation responsible for the re-ionization of the intergalactic medium. A young galaxy captured by a cosmic lens Young galaxies at a cosmic age of less than 500 million years remain largely unexplored because they are at or beyond the sensitivity limits of current large telescopes. This paper reports the use of strong gravitational lensing from a massive cluster of galaxies to observe a galaxy from the early Universe, at a redshift of z ≈ 9.6, equivalent to a cosmic age of approximately 490 million years. The authors suggest that because faint galaxies seem to be abundant at such a young cosmic age they are probably the dominant source for the early re-ionization of the intergalactic medium. Re-ionization of the intergalactic medium occurred in the early Universe at redshift z  ≈ 6–11, following the formation of the first generation of stars 1 . Those young galaxies (where the bulk of stars formed) at a cosmic age of less than about 500 million years ( z  ≲ 10) remain largely unexplored because they are at or beyond the sensitivity limits of existing large telescopes. Understanding the properties of these galaxies is critical to identifying the source of the radiation that re-ionized the intergalactic medium. Gravitational lensing by galaxy clusters allows the detection of high-redshift galaxies fainter than what otherwise could be found in the deepest images of the sky 2 . Here we report multiband observations of the cluster MACS J1149+2223 that have revealed (with high probability) a gravitationally magnified galaxy from the early Universe, at a redshift of z = 9.6 ± 0.2 (that is, a cosmic age of 490 ± 15 million years, or 3.6 per cent of the age of the Universe). We estimate that it formed less than 200 million years after the Big Bang (at the 95 per cent confidence level), implying a formation redshift of ≲14. Given the small sky area that our observations cover, faint galaxies seem to be abundant at such a young cosmic age, suggesting that they may be the dominant source for the early re-ionization of the intergalactic medium.

In this article we report on the liquid chromatography tandem mass spectrometry (LC-MS) investigation of plankton samples collected in the summer of 2006 along the Ligurian coasts, coinciding with a massive bloom of the tropical microalga Ostreopsis ovata. LC-MS analyses indicated the occurrence of putative palytoxin along with a much more abundant palytoxin-like compound never reported so far, which we named ovatoxin-a. On the basis of molecular formula, fragmentation pattern, and chromatographic behavior, the structure of ovatoxin-a appeared to be strictly related to that of palytoxin. We report also on the analysis of cultured O. ovata, which was necessary to unequivocally demonstrate that putative palytoxin and ovatoxin-a contained in field samples were actually produced by O. ovata itself.

Galaxy-cluster gravitational lenses can magnify background galaxies by a total factor of up to ~50. Here we report an image of an individual star at redshift z  = 1.49 (dubbed MACS J1149 Lensed Star 1) magnified by more than ×2,000. A separate image, detected briefly 0.26″ from Lensed Star 1, is probably a counterimage of the first star demagnified for multiple years by an object of ≳3 solar masses in the cluster. For reasonable assumptions about the lensing system, microlensing fluctuations in the stars’ light curves can yield evidence about the mass function of intracluster stars and compact objects, including binary fractions and specific stellar evolution and supernova models. Dark-matter subhaloes or massive compact objects may help to account for the two images’ long-term brightness ratio. An individual star at z  = 1.49 is gravitationally lensed and highly magnified by a foreground galaxy cluster. Fluctuations in the star’s emission provide insight on the mass function of intracluster stars, compact objects and the presence of dark-matter subhaloes.

The James Webb Space Telescope has discovered a surprising population of bright galaxies in the very early Universe (≲500 Myr after the Big Bang) that is hard to explain with conventional galaxy-formation models and whose physical properties are not fully understood. Insight into their internal physics is best captured through nebular lines, but at these early epochs, the brightest of these spectral features are redshifted into the mid-infrared and remain elusive. Using the mid-infrared instrument onboard the James Webb Space Telescope, here we present a detection of Hα and doubly ionized oxygen ([O iii ] 4959,5007 Å) from the bright, ultra-high-redshift galaxy candidate GHZ2/GLASS-z12. Based on these emission lines, we infer a spectroscopic redshift of z  = 12.33 ± 0.04, placing this galaxy just ~400 Myr after the Big Bang. These observations provide key insights into the conditions of this primaeval, luminous galaxy, which shows hard ionizing conditions rarely seen in the local Universe and probably driven by a compact and young burst (≲30 Myr) of star formation. The galaxy’s oxygen-to-hydrogen abundance is close to a tenth of the solar value, indicating a rapid metal enrichment. This study establishes the unique conditions of this notably bright and distant galaxy and the huge potential of mid-infrared observations to characterize these primordial systems. The detection of Hα reported in galaxy candidate GHZ2/GLASS-z12 provides a direct probe of star formation activity and can be used to trace massive stars with ages of ~10 Myr or younger.

At z=2, when the Universe was just 3 Gyr old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation1–4. It is believed that they were formed in intense nuclear starbursts and that they ultimately grew into the most massive local elliptical galaxies seen today, through mergers with minor companions5,6, but validating this scenario requires higher resolution observations of their centers than currently possible, even from space. Magnification due to gravitational lensing offers a unique opportunity to resolve their inner regions, as demonstrated in a recent study of a z=2.6 compact spheroidal galaxy which revealed a bulge, rotating at velocities comparable to the fastest rotating local ellipticals7. Following the same approach, here we map the stellar populations and kinematics of a lensed z=2.1478 compact galaxy, which surprisingly turn out to be a fast spinning, rotationally supported disk galaxy. Rather than in a merger-driven nuclear starburst8, its stars must thus have formed in a disk, likely fed by streams of cold gas, which were able to penetrate the hot halo gas until they were cut off by shock heating from the dark matter halo9. This result unambiguously confirm indications from a growing body of indirect evidence10–13 that the first galaxies to cease star formation must go through major changes not just in their structure, but also in their kinematics to evolve into present day ellipticals.

When the Universe was just 3 billion years old, half of the most massive galaxies had already ceased star formation, and such a galaxy has now been observed using gravitational lensing, unexpectedly turning out to be a compact, fast-spinning disk galaxy rather than a proto-bulge galaxy.

The James Webb Space Telescope has discovered a surprising population of bright galaxies in the very early Universe (≲500 Myr after the Big Bang) that is hard to explain with conventional galaxy-formation models and whose physical properties are not fully understood. Insight into their internal physics is best captured through nebular lines, but at these early epochs, the brightest of these spectral features are redshifted into the mid-infrared and remain elusive. Using the mid-infrared instrument onboard the James Webb Space Telescope, here we present a detection of Hα and doubly ionized oxygen ([O iii] 4959,5007 Å) from the bright, ultra-high-redshift galaxy candidate GHZ2/GLASS-z12. Based on these emission lines, we infer a spectroscopic redshift of z = 12.33 ± 0.04, placing this galaxy just ~400 Myr after the Big Bang. These observations provide key insights into the conditions of this primaeval, luminous galaxy, which shows hard ionizing conditions rarely seen in the local Universe and probably driven by a compact and young burst (≲30 Myr) of star formation. The galaxy's oxygen-to-hydrogen abundance is close to a tenth of the solar value, indicating a rapid metal enrichment. This study establishes the unique conditions of this notably bright and distant galaxy and the huge potential of mid-infrared observations to characterize these primordial systems.The James Webb Space Telescope has discovered a surprising population of bright galaxies in the very early Universe (≲500 Myr after the Big Bang) that is hard to explain with conventional galaxy-formation models and whose physical properties are not fully understood. Insight into their internal physics is best captured through nebular lines, but at these early epochs, the brightest of these spectral features are redshifted into the mid-infrared and remain elusive. Using the mid-infrared instrument onboard the James Webb Space Telescope, here we present a detection of Hα and doubly ionized oxygen ([O iii] 4959,5007 Å) from the bright, ultra-high-redshift galaxy candidate GHZ2/GLASS-z12. Based on these emission lines, we infer a spectroscopic redshift of z = 12.33 ± 0.04, placing this galaxy just ~400 Myr after the Big Bang. These observations provide key insights into the conditions of this primaeval, luminous galaxy, which shows hard ionizing conditions rarely seen in the local Universe and probably driven by a compact and young burst (≲30 Myr) of star formation. The galaxy's oxygen-to-hydrogen abundance is close to a tenth of the solar value, indicating a rapid metal enrichment. This study establishes the unique conditions of this notably bright and distant galaxy and the huge potential of mid-infrared observations to characterize these primordial systems.