Mount Etna, one of the most active volcanoes on Earth, exhibits unusual characteristics in terms of its geological setting, effusion rate, and volatile content. Mount Etna is closely related to the subduction of the Ionian plate below Eurasia, but, chemically, Mount Etna lavas are akin to intraplate magmatism. Unlike typical oceanic islands such as Hawaii, Mount Etna eruptive sequence starts with small volumes of tholeiitic lava, then shifts to alkaline compositions with much higher effusion rates, raising questions about its magma sources and modes of generation. Here, we propose that the lavas erupted at Mount Etna originate from the extraction of pre-existing melts stored within the Low Velocity Zone (LVZ). This zone characterizes the lithosphere-asthenosphere boundary (LAB) and is identified beneath oceanic plates by electric and seismic anomalies interpreted to reflect the presence of small melt fractions. We use geochemical data and modeling to show that extraction of such pre-existing melts in the LVZ in response to plate flexure around Sicily and, when coupled with varying degrees of melt-rock interaction, accounts for the temporal evolution of magma chemistry and eruptive volume at both Mount Etna and the earlier-formed Hyblean Plateau. Our analysis suggests that extraction of low degree melts from the LVZ can give rise to large alkaline volcanoes in specific tectonic environments. Mount Etna may be a unique place on Earth where the compositions of melts at the LAB can be studied directly on the Earth's surface.
Characterizing the mechanisms and galaxy properties conducive to the escape of ionizing (LyC) emission is necessary to accurately model the Epoch of Reionization and identify the sources that powered it. Using Hubble Space Telescope data, the Ly α and Continuum Origins Survey (LaCOS) is the first program to obtain uniform, multiwavelength subkiloparsec imaging for a large sample (42) of galaxies observed in LyC and enable statistically robust studies between LyC and resolved galaxy properties. Here, we characterize the morphology and galaxy merger properties of LaCOS galaxies and investigate their connection with the escape fraction of LyC emission f esc LyC . We find strong anticorrelations between f esc LyC and size ( r 20 , r 50 , and r 80 ) measured in filters containing emission from star-forming regions, and with the asymmetry and clumpiness in F150LP, a filter tracing UV continuum and Ly α . We find that ≥48% of LaCOS galaxies, and ≥41% of LaCOS LyC-emitters are visually classified as galaxy mergers. Galaxies robustly identified as mergers in LaCOS are at advanced stages of interaction, close to coalescence. The f esc LyC properties of robust mergers and low-probability mergers cannot be differentiated statistically, and we only find significant difference between the two populations in terms of their sizes and LyC luminosity: robust mergers having larger values. We conclude that (i) f esc LyC tends to be larger in galaxies with a small number of compact, centrally located, UV-emitting star-forming regions, (ii) mergers at advanced stages of interaction represent a sizable fraction of LyC-emitting samples at z ∼ 0.3, and (iii) mergers can facilitate the escape of LyC photons from galaxies.
Models of cosmic inflation generically predict a weak but potentially detectable amount of primordial non-Gaussianity (PNG), which can be used to obtain insights into the degrees of freedom during inflation and their interactions. The simplest types of PNG are the local and nonlocal (equilateral and orthogonal) shapes of the primordial three-point correlators, which are predicted by models with multiple light fields and derivative interactions in single-field inflation, respectively. In this paper, we place constraints on local, equilateral, and orthogonal non-Gaussianities using the power spectrum and bispectrum extracted from the first public release of the Dark Energy Spectroscopic Instrument (DESI). Our analysis makes use of higher-order clustering information through a consistent effective field theory (EFT) model for both the power spectrum and bispectrum at one-loop order. Using robust scale cuts where the EFT description is valid, we find the following constraints on PNG amplitudes: floc NL = -0.1 + 7.4, fequil NL = 719 + 390, forth NL = -200 + 100 (at 68% confidence level). Nonlocal PNG constraints can be further improved by combining highredshift DESI with legacy BOSS data and using simulation-based priors on bias parameters, yielding the strongest large-scale structure constraints to date fNLequil = 200 + 230, forth NL = -24 + 86. Our constraint on floc NL is competitive with the cosmic microwave background (CMB) limit; the combination gives floc NL = -0.0 + 4.1, 18% stronger than the CMB-only result, which represents the strongest bound on multifield inflation yet obtained.
We used the ultra-deep GLIMPSE JWST/NIRCam survey to constrain the faint end of the [O III]+H beta luminosity function (LF) down to 10(39)erg s(-1) at z similar to 7 - 9 behind the lensed Hubble Frontier Field galaxy cluster Abell S1063. We applied a spectral energy distribution fitting on a Lyman-break galaxy selected sample of 164 lensed galaxies and measured their combined H beta+[O III]lambda lambda 4960, 5008 flux to build the emission line LF. We found a [O III]+H beta LF with a faint-end slope (alpha = -1.78(-0.06)(+0.06) for z = 7 - 8 and alpha = -1.55(-0.11)(+0.11) for z = 8 - 9), which is flatter than the UV LF at similar redshifts (alpha <= -2) and suggests a lower number density of weak [O III]+H beta emitting galaxies at fixed M-UV. We analysed several possible explanations: (i) a decrease in the [O III]+H beta-to-UV ratio due to bursty star formation histories (SFHs), (ii) the effect of metallicity on the [O III]-to-H beta ratio, or (iii) signs of a faint-end turnover in the UV LF. Under the assumption of an evolving [O III]-to-H beta ratio, we separated the contribution of [O III]lambda 5008 and H beta and obtained a flatter [O III]lambda 5008 LF (alpha = -1.66(-0.05)(+0.05) for z = 7 - 8 and alpha = -1.45(-0.10)(+0.09) for z = 8 - 9) but steeper H beta LF (alpha=-1.95-0.08+0.08 for z = 7 - 8 and alpha = -1.68(-0.14)(+0.13) for z = 8 - 9). The combination of a decreasing metallicity and bursty SFH can reconcile the observed differences between the UV and [O III]+H beta LF. By converting this LF into the ionising photon-production rate N-ion, we show that galaxies with L-H alpha >= 10(39) erg s(-1), that is, with a star formation rate (SFR) (H alpha) >= 5 & times; 10(-3) M-circle dot yr(-1)) cause 31%-90% and 46%-156% of the ionising photon budget (at 7 < z < 8 and 8 < z < 9), when we assume a constant escape fraction of Lyman-continuum photon (f(esc) = 0.14). The shape of the LF further shows the negligible contribution of faint galaxies to the N-ion. Additionally, we derived the cosmic star formation rate density (SFRD), finding results consistent with previous estimates. However, the sensitivity of GLIMPSE to lower SFRs reinforces the conclusion that very faint galaxies contribute very little to N-ion and the SFRD. Our results suggests that GLIMPSE has detected the bulk of the total [O III]+H beta emission from star-forming galaxies, and that galaxies below our detection limits are likely minor contributors to cosmic re-ionisation.
Time-reversal (TR) symmetry is crucial for understanding a wide range of physical phenomena, and plays a key role in constraining fundamental particle interactions and in classifying phases of quantum matter. In this work, we introduce an ensemble of random quantum circuits that are representative of the dynamics of generic TR-invariant many-body quantum systems. We derive a general statistical mechanics model describing entanglement, many-body quantum chaos, and quantum information dynamics in such TR-invariant circuits. As an example of application of our formalism, we study the universal properties of measurement-induced phase transitions in monitored TR-invariant systems, with measurements performed in a TR-invariant basis. We find that TR invariance of the unitary part of the dynamics does not affect the universality class, unless measurement outcomes are postselected to satisfy the global TR invariance of each quantum trajectory. We confirm these predictions numerically and find, for both generic and Clifford-based evolutions, critical exponents in the case of “strong,” i.e., global TR invariance where each quantum trajectory is TR invariant.
