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Broad absorption line (BAL) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed 0.1c. BAL features are interesting as signatures of significant feedback, yet they can also compromise cosmological studies with quasars by distorting the shape of the most prominent quasar emission lines, impacting redshift accuracy and measurements of the matter density distribution traced by the Lyman α forest. We present a catalogue of BAL quasars discovered in the Dark Energy Spectroscopic Instrument (DESI) survey Early Data Release, which were observed as part of DESI Survey Validation, as well as the first two months of the main survey. We describe our method to automatically identify BAL quasars in DESI data, the quantities we measure for each BAL, and investigate the completeness and purity of this method with mock DESI observations. We mask the wavelengths of the BAL features and re-evaluate each BAL quasar redshift, finding new redshifts which are 243 km s−1 smaller on average for the BAL quasar sample. These new, more accurate redshifts are important to obtain the best measurements of quasar clustering, especially at small scales. Finally, we present some spectra of rarer classes of BALs that illustrate the potential of DESI data to identify such populations for further study.

Galaxy clusters enable unique opportunities to study cosmology, dark matter, galaxy evolution, and strongly lensed transients. We here present a new cluster-finding algorithm, CluMPR (Clusters from Masses and Photometric Redshifts), that exploits photometric redshifts (photo-z’s) as well as photometric stellar mass measurements. CluMPR uses a 2D binary search tree to search for overdensities of massive galaxies with similar redshifts on the sky and then probabilistically assigns cluster membership by accounting for photo-z uncertainties. We leverage the deep DESI Legacy Survey grzW1W2 imaging over one-third of the sky to create a catalogue of ∼ 300 000 galaxy cluster candidates out to z = 1, including tabulations of member galaxies and estimates of each cluster’s total stellar mass. Compared to other methods, CluMPR is particularly effective at identifying clusters at the high end of the redshift range considered (z = 0.75–1), with minimal contamination from low-mass groups. These characteristics make it ideal for identifying strongly lensed high-redshift supernovae and quasars that are powerful probes of cosmology, dark matter, and stellar astrophysics. As an example application of this cluster catalogue, we present a catalogue of candidate wide-angle strongly lensed quasars in Appendix C. The nine best candidates identified from this sample include two known lensed quasar systems and a possible changing-look lensed QSO with SDSS spectroscopy. All code and catalogues produced in this work are publicly available (see Data Availability).

We present a comprehensive analysis of the X-ray spectral properties of 198 newly identified active galactic nuclei (AGNs), leveraging archival data from the Chandra X-ray Observatory. All these AGNs exhibit a power-law spectral signature spanning a broad energy range of |$0.5{\!-\!}7.0$| keV, characterized by the photon index (⁠|$\Gamma$|⁠) values ranging from |$0.3^{+0.16}_{-0.14}$| to |$2.54^{+0.14}_{-0.13}$|⁠. Particularly, 76 of these AGNs display discernible levels of intrinsic absorption, after considering the Galactic absorption. The column densities associated with this local absorption (⁠|$n_{\rm H}^{\rm local}$|⁠) are within a range of |${\sim} 10^{19}{\!-\!}10^{22}\ {\rm cm^{-2}}$|⁠. We study the cosmological evolution of AGNs using the variation of |$n_{\rm H}^{\rm local}$| and |$\Gamma$| with their estimated redshift. The intrinsic spectral signature did not reveal any significant cosmological evolution; however, a deficit of hard sources at high redshift is possibly intrinsic. Our sample covers several orders of broad-band intrinsic luminosity (⁠|$L_{\rm B}^{\rm intr}$|⁠) ranging from |$4.59^{+0.41}_{-0.41} \times 10^{42}$| to |$2.4^{+0.12}_{-0.12} \times 10^{46}\, {\rm erg~s}^{-1}$| with peak at 1.84 redshift. We also investigate the hardness–luminosity diagram to further probe the AGNs. We conduct a sanity check by applying our findings to known AGNs, and the results are consistent with our observations. [ABSTRACT FROM AUTHOR]

Of over 5000 exoplanets identified so far, only a few hundred possess sub-Earth radii. The formation processes of these sub-Earths remain elusive, and acquiring additional samples is essential for investigating this unique population. In our study, we employ the GPFC method, a novel GPU phase folding algorithm combined with a convolutional neural network, on the Kepler photometry data. This method enhances the transit search speed significantly over the traditional Box-fitting Least Squares method, allowing a complete search of the known Kepler KOI data within days using a commercial GPU card. To date, we have identified five new ultra-short-period planets (USPs): Kepler-158d, Kepler-963c, Kepler-879c, Kepler-1489c, and KOI-4978.02. Kepler-879c with a radius of 0.4 R |$_{\oplus }$| completes its orbit around a G dwarf in 0.646716 d, Kepler-158d with a radius of 0.43 R |$_{\oplus }$| orbits a K dwarf star every 0.645088 d, Kepler-1489c with a radius of 0.51 R |$_{\oplus }$| orbits a G dwarf in 0.680741 d, Kepler-963c with a radius of 0.6 R |$_{\oplus }$| revolves around a G dwarf in 0.919783 d, and KOI-4978.02 with a radius of 0.7 R |$_{\oplus }$| circles a G dwarf in 0.941967 d. Among our findings, Kepler-879c, Kepler-158d, and Kepler-963c rank as the first, the third, and the fourth smallest USPs identified to date. Notably, Kepler-158d stands as the smallest USP found orbiting K dwarfs, while Kepler-963c, Kepler-879c, Kepler-1489c, and KOI-4978.02 are the smallest USPs found orbiting G dwarfs. Kepler-879c, Kepler-158d, Kepler-1489c, and KOI-4978.02 are among the smallest planets that are closest to their host stars, with orbits within 5 stellar radii. In addition, these discoveries highlight GPFC's promising capability in identifying small, new transiting exoplanets within the photometry data from Kepler, TESS , and upcoming space transit missions PLATO and ET. [ABSTRACT FROM AUTHOR]

We present an analysis of 152 355 radio sources identified in the second data release of the LOFAR Two Metre Sky Survey (LoTSS-DR2) with Sloan Digital Sky Survey (SDSS) spectroscopic redshifts in the range |$0.00 \lt z \lt 0.57$|⁠. Using Monte Carlo simulations, we determine the reliability of each source exhibiting an excess in radio luminosity relative to that predicted from their H |$\alpha$| emission, and, for a subset of 124 023 sources we combine this measurement with a full BPT analysis. Using these two independent diagnostics, we determine the reliability of each source hosting a supermassive black hole of high or low Eddington-scaled accretion rate, and combine the measurements to determine the reliability of sources belonging to each of four physical classes of objects: star-forming galaxies (SFGs), radio-quiet active galactic nuclei (RQAGN), and high- or low-excitation radio galaxies (HERGs or emission-line LERGs). The result is a catalogue that enables user-defined samples of radio sources with a reliability threshold suited to their science goal, for example prioritizing purity or completeness. Here, we select high-confidence samples of radio sources (>90 per cent reliability) to report: 38 588 radio-excess AGNs in the LoTSS-DR2 sample (362 HERGs, and 12 648 emission-line LERGs), together with 38 729 SFGs, and 18 726 RQAGN. We validate these results through comparison to literature using independent emission-line measurements, and to widely adopted WISE photometric selection techniques. While our use of SDSS spectroscopy limits our current analysis to |$\sim 4$|  per cent of the LoTSS-DR2 catalogue, our method is directly applicable to data from the forthcoming WEAVE-LOFAR survey, which will obtain over a million spectra of 144 MHz selected sources. [ABSTRACT FROM AUTHOR]

In the era of massive photometric surveys, we explore several approaches to estimate the masses of supermassive black holes (SMBHs) in active galactic nuclei (AGNs) from optical ground-based imaging, in each case comparing to the independent SMBH mass measurement obtained from spectroscopic data. We select a case-study sample of 28 type 1 AGN hosted by nearby galaxies from the Galaxy And Mass Assembly (GAMA) survey. We perform multicomponent spectral decomposition, extract the AGN component, and calculate the SMBH mass from the broad H |$\alpha$| emission line width and luminosity. The photometric g and i band data is decomposed into AGN+spheroid(+disc)(+bar) components with careful surface brightness fitting. From these, the SMBH mass is estimated using its relation with the spheroid Sérsic index or effective radius (both used for the first time on ground-based optical imaging of AGN); and the more widely used scaling relations based on bulge or galaxy stellar mass. We find no correlation between the H |$\alpha$| -derived SMBH masses and those based on the spheroid Sérsic index or effective radius, despite these being the most direct methods involving only one scaling relation. The bulge or galaxy stellar mass based methods both yield significant correlations, although with considerable scatter and, in the latter case, a systematic offset. We provide possible explanations for this and discuss the requirements, advantages, and drawbacks of each method. These considerations will be useful to optimize strategies for upcoming high quality ground-based and space-borne sky surveys to estimate SMBH masses in large numbers of AGN. [ABSTRACT FROM AUTHOR]

We analysed a GOES C6.2 class solar flare that occurred on 27 October 2003 at the heliographic position S20E29. Utilising a database developed from a simplified 3D magnetic loop model, we inferred a set of geometric and physical parameters to characterise the flare. This model, based on general properties of known solar flares and adjusted for instrument resolution, was used to replicate observations from the Nobeyama Radio Polarimeter (NoRP) spectra and the Nobeyama Radioheliograph (NoRH) brightness maps. We identified a possible range of parameters by comparing observed spectra and brightness distribution maps with modelled counterparts. The analysis involved computing a weighted mean of the one hundred best-fit model parameters, ranked by increasing χ 2 values.Across six discrete time intervals representing the gradual, impulsive, and decay phases of the flare, we observed slight variations in values for ten analysed parameters, with notable exceptions at the burst maxima, including an energy spectral index of approximately ∼ 2.34 , a photospheric magnetic field strength of around ∼ 2 308 G , and a non-thermal electron density of about ∼ 10 7.11 cm - 3 . In general, our results replicated the soft-hard-soft behaviour in the gradual-peak-decay phases of a solar flare. Therefore, we infer that the physical parameters (magnetic field strength, energy spectral index, and non-thermal electron density) were accurately recovered. However, fitting geometric parameters such as inclination, asymmetry, azimuth, loop radius, loop height, and footpoint separation proved challenging due to the limited resolution of the instruments, which affects the precise determination of loop-like flare geometries. [ABSTRACT FROM AUTHOR]

This study discusses historical records of Korea that mention "stars" possibly related to astronomical transient events. We selected 19 such records and scrutinized them by cross‐checking with records of other countries to identify those events. Ten events were identified as comets based on their described motions and tails. We further confirmed this by comparing them with records from other countries. Five events were classified as meteors based on descriptions of their movements, sizes, and shapes. We speculate that two recordings about "big stars" (大星) are typographical errors for "Mars" (火星), as the descriptions of these big stars seem to be consistent with the properties of the latter. This leaves two unidentified events, and we search lists of astronomical transients for their counterparts. Our work emphasizes the uncertainties and challenges caused by the limited information in the historical records while exploring the usefulness of historical records to enhance the understanding of astrophysical transient events. [ABSTRACT FROM AUTHOR]

Geographical research is increasingly focused on how digital technology shapes human-nature relations. This article explores how internet search engines and their associated algorithms and indexing technologies order and produce homogenising accounts of forest places. We put forward 'un-indexing' as a critical and inventive method for un-ordering and re-ordering search engine results to complicate digital perspectives on forest-society relations. We present Everything at the Forest Park, a series of four speculative catalogues we created to invite collective inquiries into the digital mediation of a forested area in Scotland – Queen Elizabeth Forest Park. Fostering a slower form of engagement with web material, the catalogues suggest how geographers and other scholars might critically repurpose, reappropriate and interrogate the algorithmically curated and advertising-oriented orderings of search engines to foster more careful and convivial forest-society relations. [ABSTRACT FROM AUTHOR]

Gaia Data Release 3 (DR3) provides the first classifications for the sources in Gaia 's all-sky database. Most Gaia sources are stars in the Milky Way, but DR3 also contains many sources that belong to nearby galaxies, as well as background galaxies and quasars. In this work, we compare the Gaia classifications from the Discrete Source Classifier (CU8-DSC) module to the more detailed and heterogeneous classifications in NED (NASA Extragalactic Database) and/or SIMBAD (Set of Identifications, Measurements and Bibliography for Astronomical Data) for sources with sky positions within twice the Holmberg radius of nearby galaxies. Matching these catalogues gives approximately |$3.2\times 10^5$| unique Gaia matches for |$4\times 10^5$| sources over 1040 galaxies (excluding some large Local Group galaxies) in the Local Volume Galaxy catalogue. Matched sources contain a lower fraction of Gaia -classified stars and higher fractions of galaxies and quasars (⁠|$\sim 95$| per cent, 2 per cent, and 2 per cent, respectively) than DR3 overall. Considering NED (SIMBAD) classifications as truth values, the balanced accuracy of Gaia classification is 0.80 (0.83): the most common disagreements are literature-classified galaxies Gaia -classified as stars and literature-classified stars Gaia -classified as quasars. Purity (P) and completeness (C) metrics show that agreement between Gaia classification and NED/SIMBAD classification is best for stars (⁠|$P\, \mathrm{ and}\, C\sim 0.9$|⁠), and decreases for quasars (⁠|$P\lt 0.3$| and |$0.7\lt C\lt 0.8$|⁠), galaxies (⁠|$0.7\lt P\lt 0.8$| and |$0.3\lt C\lt 0.6$|⁠), white dwarfs (⁠|$0.04\lt P\lt 0.6$| and |$C\sim 0.6$|⁠), and binary stars (⁠|$P\, \mathrm{ and}\, C\lt 0.1$|⁠). NED or SIMBAD sources classified only by detection wavelength are most often Gaia -classified as stars, while non-stellar components of galaxies appear in all Gaia classes. [ABSTRACT FROM AUTHOR]

In this work, the random forest algorithm galpro is implemented to generate photometric redshift posteriors, and its performance when trained and then applied to data from another survey is investigated. The algorithm is initially calibrated using a truth data set compiled from the Dark Energy Spectroscopic Instrument (DESI) Legacy survey. We find that the testing and training data sets must have very similar redshift distributions, with the range of their photometric data overlapping by at least 90 per cent in the appropriate photometric bands in order for the training data to be applicable to the testing data. galpro is again trained using the DESI data set and then applied to a sample drawn from the Panoramic Survey Telescope and Rapid Response System survey, to explore whether galpro can be trained using a trusted data set and applied to an entirely new survey, albeit one that uses a different magnitude system for its photometric bands, thus requiring careful conversion of the measured magnitudes. The results of this further test indicate that galpro does not produce accurate photometric redshift posteriors for the new survey, even where the distribution of redshifts for the two data sets overlaps by over 90 per cent. We conclude that the photometric redshifts generated by galpro are not suitable for generating estimates of photometric redshifts and their posterior distribution functions when applied to an entirely new survey, particularly one that uses a different magnitude system. However, our results demonstrate that galpro is a useful tool for inferring photometric redshift estimates in the case where a spectroscopic galaxy survey is nearly complete, but missing some spectroscopic redshift values. [ABSTRACT FROM AUTHOR]

We present the stellar value-added catalogue based on the Dark Energy Spectroscopic Instrument (DESI) Early Data Release. The catalogue contains radial velocity and stellar parameter measurements for |$\simeq$| 400 000 unique stars observed during commissioning and survey validation by DESI. These observations were made under conditions similar to the Milky Way Survey (MWS) currently carried out by DESI but also include multiple specially targeted fields, such as those containing well-studied dwarf galaxies and stellar streams. The majority of observed stars have |$16\lt r\lt 20$| with a median signal-to-noise ratio in the spectra of |$\sim$| 20. In the paper, we describe the structure of the catalogue, give an overview of different target classes observed, as well as provide recipes for selecting clean stellar samples. We validate the catalogue using external high-resolution measurements and show that radial velocities, surface gravities, and iron abundances determined by DESI are accurate to 1 km s−1, 0.3 dex, and |$\sim$| 0.15 dex respectively. We also demonstrate possible uses of the catalogue for chemo-dynamical studies of the Milky Way stellar halo and Draco dwarf spheroidal. The value-added catalogue described in this paper is the very first DESI MWS catalogue. The next DESI data release, expected in less than a year, will add the data from the first year of DESI survey operations and will contain approximately 4 million stars, along with significant processing improvements. [ABSTRACT FROM AUTHOR]

Morphology is a fundamental property of any galaxy population. It is a major indicator of the physical processes that drive galaxy evolution and in turn the evolution of the entire Universe. Historically, galaxy images were visually classified by trained experts. However, in the era of big data, more efficient techniques are required. In this work, we present a k -nearest neighbours based approach that utilizes non-parametric morphological quantities to classify galaxy morphology in Sloan Digital Sky Survey images. Most previous studies used only a handful of morphological parameters to identify galaxy types. In contrast, we explore 1023 morphological spaces (defined by up to 10 non-parametric statistics) to find the best combination of morphological parameters. Additionally, while most previous studies broadly classified galaxies into early types and late types or ellipticals, spirals, and irregular galaxies, we classify galaxies into 11 morphological types with an average accuracy of |${\sim} 80\!-\!90 \, {{\rm per\, cent}}$| per T-type. Our method is simple, easy to implement, and is robust to varying sizes and compositions of the training and test samples. Preliminary results on the performance of our technique on deeper images from the Hyper Suprime-Cam Subaru Strategic Survey reveal that an extension of our method to modern surveys with better imaging capabilities might be possible. [ABSTRACT FROM AUTHOR]

Following a few considerations on the role of catalogues as primary sources for the history of book trade in the early modern period, the article focuses on the series of indices librorum published by Aldus Manutius and his heirs over a century (1497-1597). The article will then present a selection of issues and topics that will be developed in the course of some wider research, devoted to exploring the use of catalogues as advertising ploys by the Aldine press.

We present a catalogue of dense cores and filaments in a |$3.8^\circ \times 2.4^\circ$| field around the TMC1 region of the Taurus molecular cloud. The catalogue was created using photometric data from the Herschel SPIRE and PACS instruments in the 70, 160, 250, 350, and 500 μ m continuum bands. Extended structure in the region was reconstructed from a Herschel column density map. Power spectra and probability density functions (PDFs) of this structure are presented. The PDF splits into lognormal and power-law forms, with the high-density power-law component associated primarily with the central part of TMC1. The total mass in the mapped region is 2000 M |$_\odot$|⁠ , of which 34 per cent is above an extinction of |$A_V\sim 3$| mag – a level that appears as a break in the PDF and as the minimum column density at which dense cores are found. A total of 35 dense filaments were extracted from the column density map. These have a typical full width at half-maximum (FWHM) width of 0.07 pc, but the TMC1 filament itself has a mean FWHM of |$\sim 0.13$| pc. The thermally supercritical filaments in the region are aligned orthogonal to the prevailing magnetic field direction. Derived properties for the supercritical TMC1 filament support the scenario of it being relatively young. A catalogue of 44 robust and candidate prestellar cores is created and is assessed to be complete down to 0.1 M |$_\odot$|⁠. The combined prestellar core mass function for the TMC1 and L1495 regions is well fit by a single lognormal distribution and is comparable to the standard initial mass function. [ABSTRACT FROM AUTHOR]

Clusters of galaxies are merging during the formation of large-scale structures in the Universe. Based on optical survey data, we identify a large sample of pre-mergers of galaxy clusters and merging subclusters in rich clusters. We find 39 382 partners within a velocity difference of 1500 km s |$^{-1}$| and a projected separation of 5  |$r_{500}$| around 33 126 main clusters, where |$r_{500}$| is the radius of the main cluster. Based on the galaxy distribution inside rich clusters with more than 30 member galaxy candidates, we identify subclusters by modelling the smoothed optical distribution with a two-component profile, and a coupling factor is obtained for merging subclusters in 7845 clusters. In addition, we find 3446 post-collision mergers according to the deviations of brightest cluster galaxies from other member galaxies, most of which have been partially validated by using the Chandra and XMM–Newton X-ray images. Two new bullet-like clusters have been identified by using the optical and X-ray images. The large samples of merging clusters of galaxies presented here are important databases for studying the hierarchical structure formation, cluster evolution, and the physics of intergalactic medium. [ABSTRACT FROM AUTHOR]

In this paper, a semisupervised machining learning technique had been utilized to analyse low-resolution stellar spectra from Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) Data Release 9 (DR9). We identified approximately 111 000 potential very metal-poor stars. Estimation of their stellar parameters (⁠|$T_{\rm eff}$|⁠ , |${\rm log}\, \rm {g}$|⁠ , [Fe/H]) indicate that over 99 per cent are metal-poor ([Fe/H] < −1.0), comprising 32 631 very metal-poor ([Fe/H] < −2.0), 702 extremely metal-poor ([Fe/H] < −3.0) and 30 ultra metal-poor ([Fe/H] < −4.0) stars. Based on kinematic characteristics, stars were categorized into thick disc-like, thin disc-like, and halo-like groups. We analysed their metallicity distributions (MDs) with respect to vertical height (⁠|$|Z|$|⁠) and orbital eccentricity (e). Thick disc-like stars in current sample show a clear trend of decreasing metallicty with increasing |$|Z|$| or e for the ranges −3.0 |$\lt $| [Fe/H] |$\lt $| −1.2 and |$|Z|$| |$\lt $| 3 kpc. Conversely, thin disc-like stars in current sample exhibit a slight increase in the fraction of more metal-poor stars with |$|Z|$| for the ranges −3.0 |$\lt $| [Fe/H] |$\lt $| −1.2 and |$|Z|$| |$\lt$| 1 kpc, but no obvious correlation with e. Additionally, we confirmed the presence of two prominent substructures among halo-like stars. One exhibits a high eccentricity (⁠|$e\ \gt\ 0.8$|⁠) orbit and higher metallicity, while the other follows a retrograde orbit with moderate eccentricity (⁠|$e\sim 0.6$|⁠) and lower metallicity. We believe they are related to the merger events known as Gaia Sausage and Sequoia, respectively. Furthermore, our observations indicate that the Sequoia has lower eccentricity and metallicity compared to the Gaia Sausage. [ABSTRACT FROM AUTHOR]

Accurate mock galaxy catalogues are crucial to validate analysis pipelines used to constrain dark energy models. We present a fast HOD-fitting method which we apply to the AbacusSummit simulations to create a set of mock catalogues for the DESI Bright Galaxy Survey, which contain r -band magnitudes and |$(g-r)$| colours. The halo tabulation method fits HODs for different absolute magnitude threshold samples simultaneously, preventing unphysical HOD crossing between samples. We validate the HOD fitting procedure by fitting to real-space clustering measurements and galaxy number densities from the MXXL BGS mock, which was tuned to the SDSS and GAMA surveys. The best-fitting clustering measurements and number densities are mostly within the assumed errors, but the clustering for the faint samples is low on large scales. The best-fitting HOD parameters are robust when fitting to simulations with different realizations of the initial conditions. When varying the cosmology, trends are seen as a function of each cosmological parameter. We use the best-fitting HOD parameters to create cubic box and cut sky mocks from the AbacusSummit simulations, in a range of cosmologies. As an illustration, we compare the |${}^{0.1}M_r\lt -20$| sample of galaxies in the mock with BGS measurements from the DESI one-percent survey. We find good agreement in the number densities, and the projected correlation function is reasonable, with differences that can be improved in the future by fitting directly to BGS clustering measurements. The cubic box and cut-sky mocks in different cosmologies are made publicly available. [ABSTRACT FROM AUTHOR]

We conducted a search for |$\textrm {H}\, \scriptstyle \mathrm{I}$| emission of the gas-rich galaxies in the Vela region (260° ≤ ℓ ≤ 290°, −2° ≤ b ≤ 1°) to explore the Vela Supercluster (VSCL) at V hel ∼ 18 000  |$\rm km\, s^{-1}$|⁠ , largely obscured by Galactic dust. Within the mostly Radio Frequency Interference-free band (250 < V hel < 25 000  |$\rm km\, s^{-1}$|⁠) of MeerKAT, the analysis focuses on 157 hexagonally distributed pointings extracted from the South African Radio Astronomy Observatory MeerKAT Galactic Plane Survey located in the Vela region (Vela−SMGPS). These were combined into 10 contiguous mosaics, covering an ∼90 square degrees area. Among the 843 |$\textrm {H}\, \scriptstyle \mathrm{I}$| detected sources, 39 were previously discovered in the H  i Parkes Zone of Avoidance survey (V hel < 12 000  |$\rm km\, s^{-1}$|⁠ ; rms ∼ 6  |$\rm mJy\, beam^{-1}$|⁠). With the improved rms level of the Vela−SMGPS, i.e. 0.29–0.56  |$\rm mJy\, beam^{-1}$|⁠ , our study unveils nearly 12 times more detections (471 candidates) in that same velocity range. We furthermore could identify 187 galaxy candidates with an |$\textrm {H}\, \scriptstyle \mathrm{I}$| mass limit reaching |$\log (M_{\rm HI}/\rm {\rm M}_{\odot }) = 9.44$| in the VSCL velocity range V hel ∼ 19 500 ± 3500  |$\rm km\, s^{-1}$|⁠. We find indications of two wall-like overdensities that confirm the original suspicion that these walls intersect at low latitudes around longitudes of ℓ ∼ 272°–278°. We also find a strong signature most likely associated with the Hydra/Antlia extension and evidence of a previously unknown narrow filament at V hel ∼ 12 000 |$\rm km\, s^{-1}$|⁠. This paper demonstrates the efficiency of systematic |$\textrm {H}\, \scriptstyle \mathrm{I}$| surveys with the Square Kilometre Array (SKA) precursor MeerKAT, even in the most obscured part of the Zone of Avoidance. [ABSTRACT FROM AUTHOR]

We report on the detection of three icy cavities on the nucleus of comet 67P/Churyumov–Gerasimenko. They were identified on high-resolution anaglyphs built from images acquired by the Optical, Spectroscopic, and Infrared Remote Imaging System instrument aboard the Rosetta spacecraft on 2016 April 9 and 10. Visually, they appear as bright patches of typically 15 to 30 m across whose large reflectances and spectral slopes in the visible substantiate the presence of sub-surface water ice. Using a new high-resolution photogrammetric shape model, we determined the three-dimensional shape of these cavities whose depth ranges from 20 to 47 m. Spectral slopes were interpreted with models combining water ice and refractory dark material and the water ice abundances in the cavities were found to amount to a few per cent. The determination of the lifetime of the icy cavities was strongly biased by the availability of appropriate and favourable observations, but we found evidence of values of up to 2 yr. The icy cavities were found to be connected to jets well documented in past studies. A thermal model allowed us to track their solar insolation over a large part of the orbit of the comet and a transitory bright jet on 2015 July 18 was unambiguously linked to the brief illumination of the icy bottom of one of the cavities. These cavities are likely to be the first potential subsurface access points detected on a cometary nucleus and their lifetimes suggest that they reveal pristine sub-surface icy layers or pockets rather than recently recondensed water vapour. [ABSTRACT FROM AUTHOR]

We investigate the photometric properties of 35 well-observed asteroids using dense ground-based and sparse ATLAS survey data. Focusing on two-colour photometric phase functions, derived using inverse methods, we explore the wavelength dependence. Our study reveals distinct (G 1, G 2) domains for cyan and orange filters, especially among some S-complex asteroids. For other asteroids, substantial uncertainties prevail, or their distributions of phase curve parameters overlap, precluding definitive conclusions on wavelength dependence. Notably, for S-complex objects, the effect appears systematic, characterized by lower G 2 values in the cyan filter. The effect can be explained by considering the known geometric albedo correlation: higher albedo corresponds to flatter, whereas lower albedo corresponds to steeper phase curves. In the case of equal albedo, asteroids with red spectral slopes have a more pronounced opposition effect in red and asteroids with blue spectral slopes in blue filters. We explore the variation of slope differences of orange and cyan phase curves with phase angle. For most asteroids, the largest nominal variation is observed at phase angles < 10°. This suggests that the phase colouring for the orange–cyan colour slope is more pronounced at small phase angles. Through meticulous analysis of the opposition effect amplitudes, we also pinpoint preferred rotational pole solutions. We identify inconsistencies between phase curve parameters and spectral types in specific cases. The shape- and geometry-corrected phase curves signify an important advancement in studying asteroid photometric behaviour and may offer a deeper understanding of surface and regolith properties previously obscured by these effects, such as surface roughness. [ABSTRACT FROM AUTHOR]

The Fermi /GBM instrument is a vital source of detections of gamma-ray bursts and has an increasingly important role to play in understanding gravitational-wave transients. In both cases, its impact is increased by accurate positions with reliable uncertainties. We evaluate the RoboBA and BALROG algorithms for determining the position of gamma-ray bursts detected by the Fermi /GBM instrument. We construct a sample of 54 bursts with detections both by Swift /BAT and by Fermi /GBM. We then compare the positions predicted by RoboBA and BALROG with the positions measured by BAT, which we can assume to be the true position. We find that RoboBA and BALROG are similarly precise for bright bursts whose uncertainties are dominated by systematic errors, but RoboBA performs better for faint bursts whose uncertainties are dominated by statistical noise. We further find that the uncertainties in the positions predicted by RoboBA are consistent with the distribution of position errors, whereas BALROG seems to be underestimating the uncertainties by a factor of about 2. Additionally, we consider the implications of these results for the follow-up of the optical afterglows of Fermi /GBM bursts. In particular, for the DDOTI wide-field imager we conclude that a single pointing is best. Our sample would allow a similar study to be carried out for other telescopes. [ABSTRACT FROM AUTHOR]

The advent of massive broad-band photometric surveys enabled photometric redshift estimates for unprecedented numbers of galaxies and quasars. These estimates can be improved using better algorithms or by obtaining complementary data such as narrow-band photometry, and broad-band photometry over an extended wavelength range. We investigate the impact of both approaches on photometric redshifts for quasars using data from Southern Photometric Local Universe Survey (S-PLUS) DR4, Galaxy Evolution Explorer (GALEX) DR6/7, and the unWISE catalog for the Wide-field Infrared Survey Explorer (WISE) in three machine learning methods: Random Forest, Flexible Conditional Density Estimation (FlexCoDE), and Bayesian Mixture Density Network (BMDN). Including narrow-band photometry improves the root-mean-square error by 11 per cent in comparison to a model trained with only broad-band photometry. Narrow-band information only provided an improvement of 3.8 per cent when GALEX and WISE colours were included. Thus, narrow bands play a more important role for objects that do not have GALEX or WISE counterparts, which respectively makes 92 per cent and 25 per cent of S-PLUS data considered here. Nevertheless, the inclusion of narrow-band information provided better estimates of the probability density functions obtained with FlexCoDE and BMDN. We publicly release a value-added catalogue of photometrically selected quasars with the photo- z predictions from all methods studied here. The catalogue provided with this work covers the S-PLUS DR4 area (∼3000 square degrees), containing 645 980, 244 912, 144 991 sources with the probability of being a quasar higher than, 80 per cent, 90 per cent, 95 per cent up to r < 21.3 and good photometry quality in the detection image. More quasar candidates can be retrieved from the S-PLUS data base by considering less restrictive selection criteria. [ABSTRACT FROM AUTHOR]

We present a new method for selecting A-type supergiants (A-SGs hereafter) in the LAMOST DR5 data set using the line indices, and identify 40 spectra of 30 A-SG candidates. Based on the analysis of the absolute magnitude of Gaia DR3, SIMBAD data base, ZTF light variation data, and spectral characteristics of A-SGs, we classified the 30 A-SG candidates into 18 A-SGs and 12 A-SG candidates with different levels of credibility. We also subclassify spectral types of 18 A-SGs and 12 A-SG candidates by using human eyes and find a good consistency between our results and those of MKCLASS for most of them. The spatial distribution of 18 A-SGs and 12 A-SG candidates indicates that they are located in the Galactic latitude smaller than 20○. In addition, the distribution of 13 A-SGs and 7 A-SG candidates with reliable Gaia DR3 kinematic parameters in the Toomre diagram indicates that they are located in the Galactic disc, which also suggests that they are young, massive stars. Our selection has worked out well, in that only one A-SG candidate and one A-SG appear to exhibit discrepant kinematics. [ABSTRACT FROM AUTHOR]

In order to facilitate the future study of ultra-diffuse galaxies (UDGs), we compile a catalogue of their spectroscopic properties. Using it, we investigate some of the biases inherent in the current UDG sample that have been targeted for spectroscopy. In comparison to a larger sample of UDGs studied via their spectral energy distributions (SED), current spectroscopic targets are intrinsically brighter, have higher stellar mass, are larger, more globular cluster-rich, older, and have a wider spread in their metallicities. In particular, many spectroscopically studied UDGs have a significant fraction of their stellar mass contained within their globular cluster (GC) system. We also search for correlations between parameters in the catalogue. Of note is a correlation between alpha element abundance and metallicity, as may be expected for a 'failed galaxy' scenario. However, the expected correlations of metallicity with age are not found, and it is unclear if this is evidence against a 'failed galaxy' scenario or simply due to the low number of statistics and the presence of outliers. Finally, we attempt to segment our catalogue into different classes using a machine learning K-means method. We find that the clustering is very weak and that it is currently not warranted to split the catalogue into multiple, distinct subpopulations. Our catalogue is available online, and we aim to maintain it beyond the publication of this work. [ABSTRACT FROM AUTHOR]

Galaxy clusters are the most massive gravitationally bound systems consisting of dark matter, hot baryonic gas, and stars. They play an important role in observational cosmology and galaxy evolution studies. We develop a deep learning model for segmentation of Sunyaev–Zeldovich (SZ) signal on Atacama Cosmology Telescope (ACT) +  Planck intensity maps and construct a pipeline for microwave cluster detection in the ACT footprint. The proposed model allows us to identify previously unknown galaxy clusters, i.e. it is capable of detecting SZ sources below the detection threshold adopted in the published galaxy clusters catalogues [such as ACT DR5 and Planck Sunyaev–Zeldovich 2 (PSZ2)]. In this paper, we use the derived SZ signal map to considerably improve a cluster purity in the extended catalogue of Sunyaev–Zeldovich objects from Planck data (SZcat) in the ACT footprint. From SZcat, we create a new microwave galaxy cluster catalogue (ComPACT), which includes 2962 SZ objects with cluster purity conservatively estimated as ≳74–84 per cent. We categorize objects in the catalogue into three categories, based on their cluster reliability. Within the ComPACT catalogue, there are ≳977 new clusters with respect to the ACT DR5 and PSZ2 catalogues. [ABSTRACT FROM AUTHOR]

Spectral energy distribution (SED) fitting has been extensively used to determine the nature of the faint radio source population. Recent efforts have combined fits from multiple SED-fitting codes to account for the host galaxy and any active nucleus that may be present. We show that it is possible to produce similar-quality classifications using a single energy-balance SED fitting code, prospector , to model up to 26 bands of UV–far-infrared aperture-matched photometry for ∼31 000 sources in the ELAIS-N1 field from the LOFAR Two-Metre Sky Survey (LoTSS) deep fields first data release. One of a new generation of SED-fitting codes, prospector accounts for potential contributions from radiative active galactic nuclei (AGN) when estimating galaxy properties, including star formation rates (SFRs) derived using non-parametric star formation histories. Combining this information with radio luminosities, we classify 92 per cent of the radio sources as a star-forming galaxy, high-/low-excitation radio galaxy, or radio-quiet AGN and study the population demographics as a function of 150 MHz flux density, luminosity, SFR, stellar mass, redshift, and apparent r -band magnitude. Finally, we use prospector SED fits to investigate the SFR–150 MHz luminosity relation for a sample of ∼133 000 3.6 μm-selected z < 1 sources, finding that the stellar mass dependence is significantly weaker than previously reported, and may disappear altogether at |$\log _{10} (\mathrm{SFR}/M_\odot \, \mathrm{yr}^{-1}) \gt 0.5$|⁠. This approach makes it significantly easier to classify radio sources from LoTSS and elsewhere, and may have important implications for future studies of star-forming galaxies at radio wavelengths. [ABSTRACT FROM AUTHOR]

We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251° ≤ l ≤ 358° and 2° ≤ l ≤ 61° at | b | ≤ |$1{_{.}^{\circ}}5$|⁠). SMGPS is the largest, most sensitive, and highest angular resolution 1 GHz survey of the plane yet carried out, with an angular resolution of 8 arcsec and a broad-band root-mean-square sensitivity of ∼10–20 μJy beam−1. Here, we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908–1656 MHz, power-law fits to the images, and broad-band zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-infrared classification of rare luminous blue variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realization that many of the largest radio-quiet Wide-field Infrared Survey Explorer (WISE) H  ii region candidates are not true H  ii regions; and a large sample of previously undiscovered background H  i galaxies in the Zone of Avoidance. [ABSTRACT FROM AUTHOR]

Most of the observed galaxies cannot be resolved into individual stars and are studied through their integrated spectrum using simple stellar populations (SSPs) models, with stellar libraries being a key ingredient in building them. Spectroscopic observations are increasingly being directed towards the near-infrared (NIR), where much is yet to be explored. SSPs in the NIR are still limited, and there are inconsistencies between different sets of models. One of the ways to minimize this problem is to have reliable NIR stellar libraries. The main goal of this work is to present smarty (mileS Moderate resolution neAr-infRared sTellar librarY) a ∼0.9−2.4 |$\mu$| m stellar spectral library composed of 31 stars observed with the Gemini Near-IR Spectrograph (GNIRS) at the 8.1 m Gemini North telescope and make it available to the community. The stars were chosen from the miles library, for which the atmospheric parameters are reliable (and well-tested), to populate different regions of the Hertzsprung–Russell (HR) diagram. Furthermore, five of these stars have NIR spectra available that we use to assess the quality of smarty. The remaining 26 stars are presented for the first time in the NIR. We compared the observed smarty spectra with synthetic and interpolated spectra, finding a mean difference of |$\sim 20~{{\ \rm per\ cent}}$| in the equivalent widths and ∼1 per cent in the overall continuum shape in both sets of comparisons. We computed the spectrophotometric broad-band magnitudes and colours and compared them with the 2MASS ones, resulting in mean differences up to 0.07 and 0.10 mag in magnitudes and colours, respectively. In general, a small difference was noted between the smarty spectra corrected using the continuum from the interpolated and the theoretical stars. [ABSTRACT FROM AUTHOR]

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The u -band magnitude is vital for determining stellar parameters and investigating specific astronomical objects. However, flux calibration in the u band for stars in the Galactic disc presents significant challenges. In this study, we introduce a comprehensive recalibration of u -band photometric magnitudes of the VPHAS+ Data Release 4, employing the stellar colour regression technique. By leveraging the expansive set of XP spectra and G BP photometry from Gaia Data Release 3, as well as the individual stellar extinction values provided by the literature, we have obtained precise model magnitudes of nearly 3 million stars. Our analysis identifies systematic magnitude offsets that exhibit a standard deviation of 0.063 mag across different observational visits, 0.022 mag between various CCDs, and 0.009 mag within pixel bins. We have implemented precise corrections for these observational visits, CCD chips, and pixel bins-dependent magnitude offsets. These corrections have led to a reduction in the standard deviation between the observed magnitudes and the model magnitudes from 0.088 to 0.065 mag, ensuring that the calibrated magnitudes are independent of stellar magnitude, colour, and extinction. The enhanced precision of these magnitudes substantially improves the quality of astrophysical research and offers substantial potential for furthering our understanding of stellar astrophysics. [ABSTRACT FROM AUTHOR]

We present reduced images and catalogues of photometric and emission-line data (∼230 000 and ∼8000 sources, respectively) for the WFC3 (Wide Field Camera 3) Infrared Spectroscopic Parallel (WISP) survey. These data are made publicly available on the Mikulski Archive for Space Telescopes and include reduced images from various facilities: ground-based ugri, Hubble Space Telescope (HST) WFC3, and Spitzer IRAC (Infrared Array Camera). Coverage in at least one additional filter beyond the WFC3/IR data are available for roughly half of the fields (227 out of 483), with ∼20 per cent (86) having coverage in six or more filters from u band to IRAC 3.6  |$\mu$| m (0.35–3.6  |$\mu$| m). For the lower spatial resolution (and shallower) ground-based and IRAC data, we perform PSF (point spread function)-matched, prior-based, deconfusion photometry (i.e. forced-photometry) using the tphot software to optimally extract measurements or upper limits. We present the methodology and software used for the WISP emission-line detection and visual inspection. The former adopts a continuous wavelet transformation that significantly reduces the number of spurious sources as candidates before the visual inspection stage. We combine both WISP catalogues and perform spectral energy distribution fitting on galaxies with reliable spectroscopic redshifts and multiband photometry to measure their stellar masses. We stack WISP spectra as functions of stellar mass and redshift and measure average emission-line fluxes and ratios. We find that WISP emission-line sources are typically 'normal' star-forming galaxies based on the mass–excitation diagram ([O  iii ]/Hβ versus M ⋆; 0.74 < z grism < 2.31), the galaxy main sequence (SFR versus M ⋆; 0.30 < z grism < 1.45), S 32 ratio versus M ⋆ (0.30 < z grism < 0.73), and O 32 and R 23 ratios versus M ⋆ (1.27 < z grism < 1.45). [ABSTRACT FROM AUTHOR]

We investigate emission line galaxies across cosmic time by combining the modified L-Galaxies semi-analytical galaxy formation model with the JiuTian cosmological simulation. We improve the tidal disruption model of satellite galaxies in L-Galaxies to address the time dependence problem. We utilize the public code cloudy to compute emission line ratios for a grid of H  ii region models. The emission line models assume the same initial mass function as that used to generate the spectral energy distribution of semi-analytical galaxies, ensuring a coherent treatment for modelling the full galaxy spectrum. By incorporating these emission line ratios with galaxy properties, we reproduce observed luminosity functions for H α, H β, [O  ii ], and [O  iii ] in the local Universe and at high redshifts. We also find good agreement between model predictions and observations for autocorrelation and cross-correlation functions of [O  ii ]-selected galaxies, as well as their luminosity dependence. The bias of emission line galaxies depends on both luminosity and redshift. At lower redshifts, it remains constant with increasing luminosity up to around |$\sim 10^{42.5}\, {\rm erg\, s^{-1}}$| and then rises steeply for higher luminosities. The transition luminosity increases with redshift and becomes insignificant above z  = 1.5. Generally, galaxy bias shows an increasing trend with redshift. However, for luminous galaxies, the bias is higher at low redshifts, as the strong luminosity dependence observed at low redshifts diminishes at higher redshifts. We provide a fitting formula for the bias of emission line galaxies as a function of luminosity and redshift, which can be utilized for large-scale structure studies with future galaxy surveys. [ABSTRACT FROM AUTHOR]

Thanks to Gaia DR2, we proved for the first time that a general relativistic Milky Way rotation curve is statistically indistinguishable from its state-of-the-art dark matter analogue. Those results supported the ansatz that gravitational dragging can explain the observed flatness of the Milky Way rotation curve with a consistent radial matter density profile. To challenge again such a scenario, we select 719 143 young disc stars within | z | < 1 kpc and up to R ≃ 19 kpc from Gaia DR3 providing a much larger sample of high-quality astrometric and spectrophotometric data of unprecedented homogeneity. This sample comprises 241 918 OBA stars, 475 520 RGB giants, and 1705 Cepheides that we use to fit, as with DR2, both a classical velocity profile model, i.e. with a dark matter halo, and a general relativistic analogue derived from a dust disc-scale metric. Once more, further corroborating our earlier findings, both models are found to explain, with similar statistical quality, the new observed rotational velocities derived from different combinations of the selected sets of stars belonging to the disc of our Galaxy. The geometrical effect is found to drive the velocity profile from 10 kpc outwards, while being responsible for ∼30–37 per cent of this profile already at the Sun distance, similarly to the halo contribution in the classical model. This confirms our previous results on the contribution of Einstein's geometry and pushes to further investigate the role of General Relativity in tracing the Milky Way rotation curve; notably, the origin of this gravitational dragging remains undetermined, necessitating a dedicated in-depth exploration. [ABSTRACT FROM AUTHOR]

We compile a catalogue of 578 highly probable and 62 likely red supergiants (RSGs) of the Milky Way, which represents the largest list of Galactic RSG candidates designed for continuous follow-up efforts to date. We match distances measured by Gaia DR3, 2MASS photometry, and a 3D Galactic dust map to obtain luminous bright late-type stars. Determining the stars' bolometric luminosities and effective temperatures, we compare to Geneva stellar evolution tracks to determine likely RSG candidates, and quantify contamination using a catalogue of Galactic AGB in the same luminosity-temperature space. We add details for common or interesting characteristics of RSG, such as multistar system membership, variability, and classification as a runaway. As potential future core-collapse supernova progenitors, we study the ability of the catalogue to inform the Supernova Early Warning System (SNEWS) coincidence network made to automate pointing, and show that for 3D position estimates made possible by neutrinos, the number of progenitor candidates can be significantly reduced, improving our ability to observe the progenitor pre-explosion and the early phases of core-collapse supernovae. [ABSTRACT FROM AUTHOR]

The study of the orbital period variation of short-period binary systems has been important to understand several physical phenomena, such as the emission of gravitational waves, angular momentum loss via magnetic braking, matter transfer between the components, apsidal motion, quadrupole moment variation, and presence of circumbinary bodies. With the advent of large space missions, e.g. Kepler and Transiting Exoplanet Survey Satellite (TESS), an enormous amount of high-precision photometric data with temporal coverage from years to decades has become available. Thus, in this work, we propose to study the orbital period variation of a sample of 253 binary that was observed by both Kepler and TESS and therefore with a temporal coverage of more than 10 yr. The main goal of this paper is the search and characterization of third bodies. Based on the periodicity analysis of the observed minus calculated (O − C) diagram of the sample, 75 of them showed periodic variation and therefore were classified as binary systems with third-body candidates, while the remaining 178 did not show periodic variations. This result is a two-fold increase in tertiary candidates around binary systems compared to the study carried out with only Kepler data. Although our estimated rate of third-body candidates (∼30 per cent) is higher than that obtained only with Kepler data (∼20 per cent), it should be taken as a lower limit. [ABSTRACT FROM AUTHOR]

Stellar chemical abundances have proved themselves a key source of information for understanding the evolution of the Milky Way, and the scale of major stellar surveys such as GALAH have massively increased the amount of chemical data available. However, progress is hampered by the level of precision in chemical abundance data as well as the visualization methods for comparing the multidimensional outputs of chemical evolution models to stellar abundance data. Machine learning methods have greatly improved the former; while the application of tree-building or phylogenetic methods borrowed from biology are beginning to show promise with the latter. Here, we analyse a sample of GALAH solar twins to address these issues. We apply The Cannon algorithm to generate a catalogue of about 40 000 solar twins with 14 high precision abundances which we use to perform a phylogenetic analysis on a selection of stars that have two different ranges of eccentricities. From our analyses, we are able to find a group with mostly stars on circular orbits and some old stars with eccentric orbits whose age–[Y/Mg] relation agrees remarkably well with the chemical clocks published by previous high precision abundance studies. Our results show the power of combining survey data with machine learning and phylogenetics to reconstruct the history of the Milky Way. [ABSTRACT FROM AUTHOR]

We present new radio continuum images and a source catalogue from the MeerKAT survey in the direction of the Small Magellanic Cloud. The observations, at a central frequency of 1.3 GHz across a bandwidth of 0.8 GHz, encompass a field of view ∼7° × 7° and result in images with resolution of 8 arcsec. The median broad-band Stokes I image Root Mean Squared noise value is ∼11  μ Jy beam−1. The catalogue produced from these images contains 108 330 point sources and 517 compact extended sources. We also describe a UHF (544–1088 MHz) single pointing observation. We report the detection of a new confirmed Supernova Remnant (SNR; MCSNR J0100–7211) with an X-ray magnetar at its centre and 10 new SNR candidates. This is in addition to the detection of 21 previously confirmed SNRs and two previously noted SNR candidates. Our new SNR candidates have typical surface brightness an order of magnitude below those previously known, and on the whole they are larger. The high sensitivity of the MeerKAT survey also enabled us to detect the bright end of the SMC Planetary Nebulae (PNe) sample – point-like radio emission is associated with 38 of 102 optically known PNe, of which 19 are new detections. Lastly, we present the detection of three foreground radio stars amidst 11 circularly polarized sources, and a few examples of morphologically interesting background radio galaxies from which the radio ring galaxy ESO 029–G034 may represent a new type of radio object. [ABSTRACT FROM AUTHOR]

The Transiting Exoplanet Survey Satellite (TESS) mission has provided the community with high-precision times-series photometry for ∼2.8 million stars across the entire sky via the full frame image (FFI) light curves produced by the TESS Science Processing Operations Center (SPOC). This set of light curves is an extremely valuable resource for the discovery of transiting exoplanets and other stellar science. However, due to the sample selection, this set of light curves does not constitute a magnitude-limited sample. In order to understand the effects of this sample selection, we use Gaia Data Release 2 (DR2) and Data Release 3 (DR3) to study the properties of the stars in the TESS -SPOC FFI light-curve set, with the aim of providing vital context for further research using the sample. We report on the properties of the TESS -SPOC FFI targets in Sectors 1–55 (covering Cycles 1–4). We cross-match the TESS -SPOC FFI targets with the Gaia DR2 and DR3 catalogues of all targets brighter than Gaia magnitude 14 to understand the effects of sample selection on the overall stellar properties. This includes Gaia magnitude, parallax, radius, temperature, non-single star flags, luminosity, radial velocity, and stellar surface gravity. In total, there are ∼16.7 million Gaia targets brighter than G  = 14, which when cross-matched with the TESS -SPOC FFI targets leaves ∼2.75 million. We investigate the binarity of each TESS -SPOC FFI target and calculate the radius detection limit from two detected TESS transits that could be detected around each target. Finally, we create a comprehensive main-sequence TESS -SPOC FFI target sample that can be utilized in future studies. [ABSTRACT FROM AUTHOR]

We present a catalogue of point sources detected with the Mikhail Pavlinsky ART-XC telescope onboard the SRG observatory during a wide-field survey of the Galactic Bulge that was conducted as part of the mission's calibration and performance verification phase in 2019. The survey consisted of nearly 18 d of consecutive scanning observations of the sky region | l | < 6 deg, | b | < 2.5 deg with the median sensitivity of 4 × 10−13 erg s−1 cm−2 in the 4–12 keV energy band, which allows the detection of sources down to a luminosity of 3 × 1033 erg s−1 near the Galactic Centre. Using a maximum-likelihood-based algorithm, 172 sources were detected. Of these, 153 are registered on the average 4–12 keV map and 18 sources are either extremely hard (detected only at energies above 7 keV) or highly variable (detected only in individual scans shorter than a day). For 121 sources, there are plausible counterparts in other X-ray source catalogues, including 43 with known classification. The remaining 51 sources are previously unknown objects, discovered by ART-XC during the Galactic Bulge survey. [ABSTRACT FROM AUTHOR]

A less explored aspect of dwarf galaxies is their metallicity evolution. Generally, dwarfs have lower metallicities than Hubble sequence late-type galaxies, but in reality, dwarfs span a wide range of metallicities with several open questions regarding the formation and evolution of the lowest and the highest metallicity dwarfs. We present a catalogue of 3459 blue, nearby, star-forming dwarf galaxies extracted from SDSS DR-16 including calculation of their metallicities using the mean of several calibrators. To compile our catalogue we applied redshift, absolute magnitude, stellar mass, optical diameter, and line flux signal-to-noise criteria. This produced a catalogue from the upper end of the dwarf galaxy stellar mass range. Our catalogued dwarfs have blue g – i colours and Hβ equivalent widths, indicative of having undergone a recent episode of star formation, although their star formation rates (SFRs) suggest only a moderate to low enhancement in star formation, similar to the SFRs in low surface brightness and evolved tidal dwarfs. While the catalogued dwarfs cover a range of metallicities, their mean metallicity is ∼0.2 dex below solar metallicity, indicating relatively chemically evolved galaxies. The vast majority of the catalogue, with clean photometry, are relatively isolated dwarfs with only modest SFRs and a narrow range of g – i colour, consistent with internally driven episodic mild bursts of star formation. The presented catalogue's robust metallicity estimates for nearby SDSS dwarf galaxies will help target future studies to understand the physical processes driving the metallicity evolution of dwarfs. [ABSTRACT FROM AUTHOR]

Young stellar clusters are predominantly the hub of star formation and hence, ideal to perform comprehensive studies over the least explored substellar regime. Various unanswered questions like the mass distribution in brown dwarf regime and the effect of diverse cluster environment on brown dwarf formation efficiency still plague the scientific community. The nearby young cluster, IC 1396 with its feedback-driven environment, is ideal to conduct such study. In this paper, we adopt a multiwavelength approach, using deep Subaru HSC along with other data sets and machine learning techniques to identify the cluster members complete down to ∼ 0.03 M⊙ in the central 22 arcmin area of IC 1396. We identify 458 cluster members including 62 brown dwarfs which are used to determine mass distribution in the region. We obtain a star-to-brown dwarf ratio of ∼ 6 for a stellar mass range 0.03–1 M⊙ in the studied cluster. The brown dwarf fraction is observed to increase across the cluster as radial distance from the central OB-stars increases. This study also compiles 15 young stellar clusters to check the variation of star-to-brown dwarf ratio relative to stellar density and ultraviolet (UV) flux ranging within 4–2500 stars pc−2 and 0.7–7.3  G 0, respectively. The brown dwarf fraction is observed to increase with stellar density but the results about the influence of incident UV flux are inconclusive within this range. This is the deepest study of IC 1396 as of yet and it will pave the way to understand various aspects of brown dwarfs using spectroscopic observations in future. [ABSTRACT FROM AUTHOR]

We present a spectroscopic survey of Ly α emitters in the Extended Groth Strip (EGS) field, targeting the regime near the Epoch of Reionization. Using Keck/DEep Imaging Multi-Object Spectrograph, we observed 947 high- z candidates with photometric redshifts from 3 < z phot < 7 and down to an H -band (Hubble Space Telescope /Wide Field Camera 3 F160W) magnitude limit of <27.5. Observations were taken over the course of eight nights, with integration times ranging from 4 to 7.8 h. Our survey secured 137 unique redshifts, 126 of which are Ly α emitters at 2.8 < z < 6.3 with a mean redshift of |$\overline{z} = 4.3$|⁠. We provide a comprehensive redshift catalogue for our targets, as well as the reduced one- and two-dimensional spectra for each object. These observations will provide an important auxiliary data set for the JWST Directors Discretionary Early Release Science programme the Cosmic Evolution Early Release Science Survey, which recently completed near- and mid-infrared imaging and spectroscopy of galaxies in the EGS field. [ABSTRACT FROM AUTHOR]

We present and validate the catalogue of Lyman-α forest fluctuations for 3D analyses using the Early Data Release (EDR) from the Dark Energy Spectroscopic Instrument (DESI) survey. We used 88 511 quasars collected from DESI Survey Validation (SV) data and the first two months of the main survey (M2). We present several improvements to the method used to extract the Lyman-α absorption fluctuations performed in previous analyses from the Sloan Digital Sky Survey (SDSS). In particular, we modify the weighting scheme and show that it can improve the precision of the correlation function measurement by more than 20 per cent. This catalogue can be downloaded from https://data.desi.lbl.gov/public/edr/vac/edr/lya/fuji/v0.3 , and it will be used in the near future for the first DESI measurements of the 3D correlations in the Lyman-α forest. [ABSTRACT FROM AUTHOR]

We explore systematically the shocked gas in the first Galactic quadrant of the Milky Way using the United Kingdom Infrared Telescope (UKIRT) Wide-field Infrared Survey for Fe+ (UWIFE). The UWIFE survey is the first imaging survey of the Milky Way in the [Fe  ii ] 1.644 μm emission line and covers the Galactic plane in the first Galactic quadrant (7° < |$\mathit {l}$| < 62°; |$|b| $| ≲ 1 |$_{.}^{\circ }$| 5). We identify 204 extended ionized Fe objects (IFOs) using a combination of a manual and automatic search. Most of the IFOs are detected for the first time in the [Fe  ii ] 1.644 μm line. We present a catalogue of the measured sizes and fluxes of the IFOs and searched for their counterparts by performing positional cross-matching with known sources. We found that IFOs are associated with supernova remnants (25), young stellar objects (100), H  ii regions (33), planetary nebulae (17), and luminous blue variables (4). The statistical and morphological properties are discussed for each of these. [ABSTRACT FROM AUTHOR]

The automatic classification of X-ray detections is a necessary step in extracting astrophysical information from compiled catalogues of astrophysical sources. Classification is useful for the study of individual objects, statistics for population studies, as well as for anomaly detection, that is, the identification of new unexplored phenomena, including transients and spectrally extreme sources. Despite the importance of this task, classification remains challenging in X-ray astronomy due to the lack of optical counterparts and representative training sets. We develop an alternative methodology that employs an unsupervised machine learning approach to provide probabilistic classes to Chandra Source Catalog sources with a limited number of labelled sources, and without ancillary information from optical and infrared catalogues. We provide a catalogue of probabilistic classes for 8756 sources, comprising a total of 14 507 detections, and demonstrate the success of the method at identifying emission from young stellar objects, as well as distinguishing between small- and large-scale compact accretors with a significant level of confidence. We investigate the consistency between the distribution of features among classified objects and well-established astrophysical hypotheses such as the unified active galactic nucleus model. This provides interpretability to the probabilistic classifier. Code and tables are available publicly through GitHub. We provide a web playground for readers to explore our final classification at https://umlcaxs-playground.streamlit.app. [ABSTRACT FROM AUTHOR]

This paper presents GPFC, a novel Graphics Processing Unit (GPU) Phase Folding and Convolutional Neural Network (CNN) system to detect exoplanets using the transit method. We devise a fast-folding algorithm parallelized on a GPU to amplify low signal-to-noise ratio transit signals, allowing a search at high precision and speed. A CNN trained on two million synthetic light curves reports a score indicating the likelihood of a planetary signal at each period. While the GPFC method has broad applicability across period ranges, this research specifically focuses on detecting ultrashort-period planets with orbital periods less than one day. GPFC improves on speed by three orders of magnitude over the predominant Box-fitting Least Squares (BLS) method. Our simulation results show GPFC achieves 97 per cent training accuracy, higher true positive rate at the same false positive rate of detection, and higher precision at the same recall rate when compared to BLS. GPFC recovers 100 per cent of known ultrashort-period planets in Kepler light curves from a blind search. These results highlight the promise of GPFC as an alternative approach to the traditional BLS algorithm for finding new transiting exoplanets in data taken with Kepler and other space transit missions such as K 2, TESS , and future PLATO and Earth 2.0. [ABSTRACT FROM AUTHOR]

The morphological diversity of galaxies is a relevant probe of galaxy evolution and cosmological structure formation. However, in large sky surveys, even the morphological classification of galaxies into two classes, like late-type (LT) and early-type (ET), still represents a significant challenge. In this work, we present a Deep Learning (DL) based morphological catalogue built from images obtained by the Southern Photometric Local Universe Survey (S-PLUS) Data Release 3 (DR3). Our DL method achieves a purity rate of 98.5 per cent in accurately distinguishing between spiral, as part of the larger category of LT galaxies, and elliptical, belonging to ET galaxies. Additionally, we have implemented a secondary classifier that evaluates the quality of each galaxy stamp, which allows to select only high-quality images when studying properties of galaxies on the basis of their DL morphology. From our LT/ET catalogue of galaxies, we recover the expected colour–magnitude diagram in which LT galaxies display bluer colours than ET ones. Furthermore, we also investigate the clustering of galaxies based on their morphology, along with their relationship to the surrounding environment. As a result, we deliver a full morphological catalogue with 164 314 objects complete up to r petro < 18, covering ∼1800 deg2, from which ∼55 000 are classified as high reliability, including a significant area of the Southern hemisphere that was not covered by previous morphology catalogues. [ABSTRACT FROM AUTHOR]

Analysis of 28 manuscripts of Gregorius IX Decretales kept in Spain that were identified in the catalogues of manuscripts kept in I.R.H.T. and at the Bibliothèque nationale de France. These reports deal with the origin and the dating, the recipients, the texts, the ornamentation, the pecia, the owners, and the bibliography. The graphics inform us about the distribution of the data. These manuscripts were produced in Italy and France, and date from the XIIIth to the XIVth centuries. The recipients are Bologna and Paris. The explicits inform us about artisans. These manuscripts have especially a painted ornamentation. Three manuscripts have pecia’s mentions. The owners are students, jurists, ecclesiastics and religious houses.