The time-delay model is the way we interpret the diagram [X/Fe] vs. [Fe/H], where X is the abundance of a generic element from carbon to uranium. This interpretation is based on the lifetimes of stars of different masses producing different elements. The abundance of Fe ([Fe/H]) traces the "stellar metallicity" and is due to supernovae Type Ia, which are believed to be the major producers of Fe, and in part to supernovae core-collapse. In particular, if X is an alpha-element, produced on short timescales from massive stars, the ratio [alpha/Fe] will show an overabundance of the alpha-elements relative to Fe at low metallicity. In fact, the bulk of Fe is produced with a time delay relative to alpha-elements, since Type Ia supernovae are white dwarfs in binary systems and they can have lifetimes as long as the age of the Universe. In this paper, I will show how powerful is the time-delay model in order to interpret the abundance patterns observed in stars and interstellar gas, since it allows us to put constraints on stellar nucleosynthesis as well as on the star formation histories of galaxies. I will present some applications of the time-delay model, in particular to the chemical evolution of the Milky Way and galaxies of different morphological type as well as to the identification of high redshift objects by means of their abundances.
The availability of asteroseismic constraints for tens of thousands of red giant (RG) stars has opened the door to robust age estimates, enabling time-resolved studies of different populations of stars in the Milky Way. This study leverages data from Kepler, K2, and TESS, in conjunction with astrometric data from Gaia DR3 and spectroscopic constraints from APOGEE DR17 and GALAH DR3, to infer parameters for over 17,000 RGs. We use the code PARAM to homogeneously infer stellar properties considering in detail the sensitivity of our results to different choices of observational constraints. We focus on age estimation, identifying potentially unreliable age determinations, and highlight stars with unreliable $Δν$ measurements based on comparisons using Gaia luminosities. These are particularly relevant in K2 data due to the short duration of the observations of each campaign, and therefore important to characterise for Galactic archaeology studies where the spatial range of K2 is a benefit. Thanks to the combination of data from different missions we explore trends in age, mass, and orbital parameters such as $R_\mathrm{g}$ and $Z_\mathrm{max}$, and examine time-resolved [$α$/M]-[Fe/H] planes across different Galactic regions. Additionally, we compare age distributions in low- and high-$α$ populations and chemically selected ex situ stars. The study also extends known mass-[C/N] ratio relationships to lower masses. The catalogues resulting from this work will be instrumental in addressing key questions in Galactic archaeology and stellar evolution, and to improve training sets for machine-learning-based age estimations.
Asteroseismology, the study of stellar oscillations, and stellar modeling both offer profound insights into the fundamental properties and evolution of stars. With pySYD, a new open-source Python package, we were able to constrain the asteroseismic global parameters, $ν_{max}$ and $Δν$, for 82 solar-like oscillating subgiant and lower red giant stars, filling in the region between the Kepler dwarfs and giants. Using asteroseismic scaling relations, we were able to compute seismic masses, radii, and surface gravities for our entire sample with average errors of 0.21 $M_{\bigodot}$, 0.27 $R_{\bigodot}$, and 0.06 dex respectively. Using 4 stellar modeling grids we determine and compare stellar ages for our sample. We find that our age distribution from stellar modeling is consistent with other local star samples. We find small consistent offsets from model predictions across our regime, but offsets were worse at higher gravities (log(g) $\geq$ 3.5 dex), suggesting the need for better calibration. Finally, we discuss our sample in the context of galactic archaeology and show how ages like these could be used to identify and study binary system evolution and galactic evolution in the future. All in all, we show that asteroseismology can be successfully performed with TESS data and can continue to make an impact on our understanding of stellar physics and galactic archaeology.
The accelerating growth of photographic collections has outpaced manual cataloguing, motivating the use of vision language models (VLMs) to automate metadata generation. This study examines whether Al-generated catalogue descriptions can approximate human-written quality and how generative Al might integrate into cataloguing workflows in archival and museum collections. A VLM (InternVL2) generated catalogue descriptions for photographic prints on labelled cardboard mounts with archaeological content, evaluated by archive and archaeology experts and non-experts in a human-centered, experimental framework. Participants classified descriptions as AI-generated or expert-written, rated quality, and reported willingness to use and trust in AI tools. Classification performance was above chance level, with both groups underestimating their ability to detect Al-generated descriptions. OCR errors and hallucinations limited perceived quality, yet descriptions rated higher in accuracy and usefulness were harder to classify, suggesting that human review is necessary to ensure the accuracy and quality of catalogue descriptions generated by the out-of-the-box model, particularly in specialized domains like archaeological cataloguing. Experts showed lower willingness to adopt AI tools, emphasizing concerns on preservation responsibility over technical performance. These findings advocate for a collaborative approach where AI supports draft generation but remains subordinate to human verification, ensuring alignment with curatorial values (e.g., provenance, transparency). The successful integration of this approach depends not only on technical advancements, such as domain-specific fine-tuning, but even more on establishing trust among professionals, which could both be fostered through a transparent and explainable AI pipeline.
The critical examination of Hong Kong’s identity and the spatial turn in narrative forms were two prominent characteristics of Hong Kong literature in the late 20th century. Kai-cheung Dung’s novel The Atlas: Archaeology of an Imaginary City, published in 1997, the year of Hong Kong’s handover, addresses this issue, embodying the pursuit and deconstruction of Hong Kong’s local consciousness. This paper focuses on the postmodern features of this work from the dimensions of time and space, including: (1) the dialectical relationship between time and space; (2) the construction of the third space; (3) the latent text of Hong Kong identity. Kai-cheung Dung tries to create an imaginary space that opposes the forgotten and subverted Hong Kong of reality. It is an infinitely expanding literary universe, in which he explores the city's complex nature and pursues a sense of self-orientation born between forgetting and remembering. Through a detailed analysis of The Atlas: Archaeology of an Imaginary City, the opening work of Kai-cheung Dung’s Series of V City, this paper aims to complete the understanding of his continually evolving literary world—revealing a stable internal unity beneath the fragmented and disjointed textual representations.
Precise asteroseismic parameters allow one to quickly estimate radius and mass distributions for large samples of stars. A number of automated methods are available to calculate the frequency of maximum acoustic power ($ν_{\mathrm{max}}$) and the frequency separation between overtone modes ($Δν$) from the power spectra of red giants. However, filtering through the results requires either manual vetting, elaborate averaging across multiple methods, or sharp cuts in certain parameters to ensure robust samples of stars free of outliers. Given the importance of ensemble studies for Galactic archaeology and the surge in data availability, faster methods for obtaining reliable asteroseismic parameters are desirable. We present a neural network classifier that vets $Δν$ by combining multiple features from the visual $Δν$ vetting process. Our classifier is able to analyse large numbers of stars determining whether their measured $Δν$ are reliable thus delivering clean samples of oscillating stars with minimal effort. Our classifier is independent of the method used to obtain $ν_{\mathrm{max}}$ and $Δν$, and therefore can be applied as a final step to any such method. Tests of our classifier's performance on manually vetted $Δν$ measurements reach an accuracy of 95%. We apply the method to giants observed by K2 Galactic Archaeology Program and find that our results retain stars with astrophysical oscillation parameters consistent with the parameter distributions already defined by well-characterised Kepler red giants.
Jiachen Xu, Junlin Guo, James Zimmer-Dauphinee
et al.
Archaeology has long faced fundamental issues of sampling and scalar representation. Traditionally, the local-to-regional-scale views of settlement patterns are produced through systematic pedestrian surveys. Recently, systematic manual survey of satellite and aerial imagery has enabled continuous distributional views of archaeological phenomena at interregional scales. However, such 'brute force' manual imagery survey methods are both time- and labor-intensive, as well as prone to inter-observer differences in sensitivity and specificity. The development of self-supervised learning methods offers a scalable learning scheme for locating archaeological features using unlabeled satellite and historical aerial images. However, archaeological features are generally only visible in a very small proportion relative to the landscape, while the modern contrastive-supervised learning approach typically yields an inferior performance on highly imbalanced datasets. In this work, we propose a framework to address this long-tail problem. As opposed to the existing contrastive learning approaches that treat the labelled and unlabeled data separately, our proposed method reforms the learning paradigm under a semi-supervised setting in order to utilize the precious annotated data (<7% in our setting). Specifically, the highly unbalanced nature of the data is employed as the prior knowledge in order to form pseudo negative pairs by ranking the similarities between unannotated image patches and annotated anchor images. In this study, we used 95,358 unlabeled images and 5,830 labelled images in order to solve the issues associated with detecting ancient buildings from a long-tailed satellite image dataset. From the results, our semi-supervised contrastive learning model achieved a promising testing balanced accuracy of 79.0%, which is a 3.8% improvement as compared to other state-of-the-art approaches.
Sophie Krausz, Caroline Millereux, Marion Bouchet
et al.
The oppidum of Châteaumeillant (Cher) belongs to the civitas of the Bituriges, whose boundaries correspond approximately to those of the current departments of Cher, Indre, and to which portions of Allier and Loir-et-Cher must be added. Located about 60 km from Bourges/Avaricum (Cher), the capital of this territory, the Mediolanum of the Tabula Peutingeriana occupies a privileged position at the southern end of Berry, the oppidum having been installed on the highest part of a rectangular promontory measuring 60 ha. Discovered in the 19th c. by Émile Chénon, the oppidum of Châteaumeillant was the subject of major archaeological excavations in the 1950s and 1960s under the direction of Émile Hugoniot and Jacques Gourvest. From 2001 to 2018, subsequent excavations focused on the Gallic habitat, as well as on the imposing fortification. The excavations revealed a dense and continuous occupation that began around 200 BC, through the La Tène C2 period. As early as La Tène D1, around 150 BC, shipments of Italian amphorae poured into Châteaumeillant. Then, around 100 BC, the town was equipped with a murus gallicus enclosing the 27 ha of the southern half of the promontory. The site subsequently peaked in terms of growth, though the rate of Italian wine imports remained steady. During the Gallic War, the murus gallicus was reinforced by a massive rampart preceded by a 45 m wide flat-bottomed ditch (Krausz 2007a; 2014; 2019; 2021; Krausz, Millereux 2019). Traces of fire observed in the La Tène D2 habitat suggest that Châteaumeillant is likely one of the twenty Bituriges towns to have been burnt down at the behest of Vercingetorix (Krausz 2009a). The town was rebuilt in the Augustan period and the occupation of the promontory continued through to the present day, without interruption. In the areas explored between 2008 and 2018 (A to G), several buildings, constructed on posts, were excavated. Some of them were built overtop large quadrangular pits that would have served as cellars. The archaeological material discovered in this zone argues in favour of areas B and C having served a craftworking and commercial function, rather than as exclusively residential areas. The presence of cellars and large pits, which would have been used to store foodstuffs that might be used for trading would appear to corroborate this interpretation of function. It is in this part of the oppidum that the renowned “amphorae cellars” were discovered in the 19th c. It was only possible to explore one such cellar during the recent excavations (2012 to 2016) and it is therefore the object of study of this article. The cellar contained the remains of 33 Italic amphorae. During a second phase of use, a well (St 512) was dug in the eastern half of this cellar. Its protected excavation yielded an exceptional assemblage, dated to the final La Tène period: in addition to some 1,500 ceramic sherds, an anthropomorphic stone statue, a human skull with traces of de-fleshing and an andiron protome of a horse were deposited at the bottom of the well. The body of the andiron is complete and well preserved, decorated with a combination of white paint and engravings. The object measures 0.39 m in height, from the hoof to the top of the horse’s head. An anthropomorphic statue and a human skull were discovered in the layer above. The statue was lying face down, 10 cm from the human skull. This sculpture represents a male figure, whose head and right hand were preserved; the hand is holding a ring to the centre of the chest. Below this ring, the statue was previously and intentionally broken. Following this damage, the upper portion of the statue (head and torso) was deposited in the well, while the base was found in a small pit in Zone B, located 8 m north of the well. It is sculpted in the round, in a particularly fine Châteaumeillant sandstone, finer than that of the statue from well F.II of the Kasmareck Garden discovered within the oppidum in 1960. Both are, undoubtedly, Celtic busts. In addition to this type of bust, another category of statues are seated figures, recognizable by virtue of their crossed legs (Coulon, Krausz 2013). Sitting busts present one or both hands resting on the chest and often wear a torque around the neck. In the statue’s current state, and with the upper part combined with the lower part, it measures 0.50 m in total height. Overall, the width varies little: from the head (10 cm), through the torque and the shoulders (12 cm) to the lower portion (15 cm). Thus, there is a variation of 5 cm from top to bottom, resulting in a small but constant broadening. This slight variation confirms that the statue is part of a rectangular block that widens slightly towards the bottom. Below the right hand holding the ring, the lower block presents no further figural representation. However, it has been carved in such a way as to provide an end that was likely tapered or pointed, a feature that could have allowed the sculpture to be driven into the ground. As with other Gallic bust statues, certain anatomical and ornamental features are highlighted: the facial features, the hairstyle and the ears, the torque around the neck and the representation of the right arm and hand. As for the human skull, it was deposited in the pit without its mandible or any other accompanying skeletal element. Only the molars and premolars remain from the upper dentition, while the other teeth were lost post-mortem, though not within the well. The skull belonged to a young adult, whose age was estimated between 17 and 25 years of age. The sex is undetermined, but most likely male. Several incisions visible on the calvaria (or skullcap), as well as on the zygomatic processes of the temporal bones suggest that it was de-fleshed, removing the scalp, and detaching the mandible and atlas. The polished appearance of the frontal bone, along with a small eroded area in the centre could be the result of exposure to touching or weathering, at least in this anterior portion. Similarly, the cracking and darkening of the tooth enamel could be the result of being placed in an open-air setting. The loss of the canines and incisors is further indication of the possibility that the skull was exposed, possibly showcased in an elevated manner. The Gauls’ marked interest in heads is known from ancient times, and the practice of removing skulls and subjecting them to a particular treatment, separate from the rest of the skeleton is attested to in Gaul from the 5th to the 1st c. BC. The presence of these remarkable objects in well 512 reveals the unique and ritualistic nature of the deposit, in the context of the La Tène habitat. It combines the representation of a male figure set in stone with a severed head. Well 512 and cellar 437 constitute an exceptional archaeological ensemble, unprecedented in a La Tène period habitat. Indeed, it concentrates numerous cultural and social characteristics of the La Tène D period: statuary, a ritual deposit, wells and an amphora cellar. This collaborative article proposes a detailed study of the two structures, the objects discovered therein and their chronology.
Cecilia Padilla-Iglesias, Cecilia Padilla-Iglesias, Karen L. Kramer
Language is the human universal mode of communication, and is dynamic and constantly in flux accommodating user needs as individuals interface with a changing world. However, we know surprisingly little about how language responds to market integration, a pressing force affecting indigenous communities worldwide today. While models of culture change often emphasize the replacement of one language, trait, or phenomenon with another following socioeconomic transitions, we present a more nuanced framework. We use demographic, economic, linguistic, and social network data from a rural Maya community that spans a 27-year period and the transition to market integration. By adopting this multivariate approach for the acquisition and use of languages, we find that while the number of bilingual speakers has significantly increased over time, bilingualism appears stable rather than transitionary. We provide evidence that when indigenous and majority languages provide complementary social and economic payoffs, both can be maintained. Our results predict the circumstances under which indigenous language use may be sustained or at risk. More broadly, the results point to the evolutionary dynamics that shaped the current distribution of the world’s linguistic diversity.
The existence of massive stellar black hole binaries (MBHBs), with primary black hole (BH) masses $\ge 31 \, M_\odot$, was proven by the detection of the gravitational wave (GW) event GW150914 during the first LIGO/Virgo observing run (O1), and successively confirmed by seven additional GW signals discovered in the O1 and O2 data. By adopting the galaxy formation model \texttt{GAMESH} coupled with binary population synthesis (BPS) calculations, here we investigate the origin of these MBHBs by selecting simulated binaries compatible in mass and coalescence redshifts. We find that their cosmic birth rates peak in the redshift range $6.5 \leq z \leq 10$, regardless of the adopted BPS. These MBHBs are then old systems forming in low-metallicity ($Z \sim [0.01-0.1] \, Z_{\odot}$), low-stellar-mass galaxies, before the end of cosmic reionization, i.e. significantly beyond the peak of cosmic star formation. GW signals generated by coalescing MBHBs open up new possibilities to probe the nature of stellar populations in remote galaxies, at present too faint to be detected by available electromagnetic facilities.
Nathan R. Sandford, Daniel R. Weisz, Yuan-Sen Ting
Increasingly powerful and multiplexed spectroscopic facilities promise detailed chemical abundance patterns for millions of resolved stars in galaxies beyond the Milky Way (MW). Here, we employ the Cramér-Rao Lower Bound (CRLB) to forecast the precision to which stellar abundances for metal-poor, low-mass stars outside the MW can be measured for 41 current (e.g., Keck, MMT, VLT, DESI) and planned (e.g., MSE, JWST, ELTs) spectrograph configurations. We show that moderate resolution ($R\lesssim5000$) spectroscopy at blue-optical wavelengths ($λ\lesssim4500$ Å) (i) enables the recovery of 2-4 times as many elements as red-optical spectroscopy ($5000\lesssimλ\lesssim10000$ Å) at similar or higher resolutions ($R\sim 10000$) and (ii) can constrain the abundances of several neutron capture elements to $\lesssim$0.3 dex. We further show that high-resolution ($R\gtrsim 20000$), low S/N ($\sim$10 pixel$^{-1}$) spectra contain rich abundance information when modeled with full spectral fitting techniques. We demonstrate that JWST/NIRSpec and ELTs can recover (i) $\sim$10 and 30 elements, respectively, for metal-poor red giants throughout the Local Group and (ii) [Fe/H] and [$α$/Fe] for resolved stars in galaxies out to several Mpc with modest integration times. We show that select literature abundances are within a factor of $\sim$2 (or better) of our CRLBs. We suggest that, like ETCs, CRLBs should be used when planning stellar spectroscopic observations. We include an open source python package, \texttt{Chem-I-Calc}, that allows users to compute CRLBs for spectrographs of their choosing.
This study concerns the problem of diagnosing the materials of transitional period from the Bronze Age to the Early Iron Age on the territory of the Urals and Kazakhstan steppes. The purpose of the work is the presentation and analysis of new materials (the Shatmantamak I burial ground) using radiocarbon dating methods. On the basis of comprehensive analysis and comparison with synchronous and asynchronous materials, the authors concluded that the burial represents a rare example of a site marking the transition period from Final Bronze Age to the Early Iron Age. The results of dating for these periods were summarized for the territory from the Volga-Ural to East Kazakhstan to determine the position of new materials in the periodization system. Some of the results are published for the first time. Generalization of synchronous materials of the 9th – 8th centuries cal BC demonstrated a mosaic pattern of cultural traditions, as well as the asynchronous transition to the Early nomads Epoch in the territories west and east of the Ural Mountains. Unfortunately, the author’s conclusions rely on a relatively small series of dating results, which require significant expansion due to new analyses.
Cameron Browne, Dennis J. N. J. Soemers, Éric Piette
et al.
Digital Archaeoludology (DAL) is a new field of study involving the analysis and reconstruction of ancient games from incomplete descriptions and archaeological evidence using modern computational techniques. The aim is to provide digital tools and methods to help game historians and other researchers better understand traditional games, their development throughout recorded human history, and their relationship to the development of human culture and mathematical knowledge. This work is being explored in the ERC-funded Digital Ludeme Project. The aim of this inaugural international research meeting on DAL is to gather together leading experts in relevant disciplines - computer science, artificial intelligence, machine learning, computational phylogenetics, mathematics, history, archaeology, anthropology, etc. - to discuss the key themes and establish the foundations for this new field of research, so that it may continue beyond the lifetime of its initiating project.