Ian Selby; E. González-Solares; Anna Breger; Michael Roberts; L. Escudero; Judith Babar; James H.F. Rudd; N. A. Walton; Evis Sala; Carola‐Bibiane Schönlieb; Jonathan Weir‐McCall; Michael Roberts; Sören Dittmer; Ian Selby; Anna Breger; Matthew Thorpe; Julian Gilbey; Jonathan Weir‐McCall; Judith Babar; Effrossyni Gkrania‐Klotsas; Jacobus Preller; Lorena Escudero Sánchez; Andrew N. Priest; Anna Korhonen; Emily Jefferson; Georg Langs; Helmut Prosch; Martin J. Graves; Guang Yang; Xiaodan Xing; Nan Yang; Ming Li; Jan Stanczuk; Jing Tang; Tolou Shadbahr; Philip Teare; Mishal Patel; Marcel Wassink; Markus Holzer; E. González-Solares; Nicholas Walton; Píetro Lió; James H.F. Rudd; John A. D. Aston; Evis Sala; Carola‐Bibiane Schönlieb
Radiology Artificial Intelligence · DOI
This article presents a suite of quality control tools for chest radiographs based on traditional and artificial intelligence methods, developed and tested with data from 39 centers in seven countries.
Michael J. Wilensky; Melis O Irfan; Philip Bull
Monthly Notices of the Royal Astronomical Society · DOI
ABSTRACT The 408 MHz Haslam map is widely used as a low-frequency anchor for the intensity and morphology of Galactic synchrotron emission. Multifrequency, multi-experiment fits show evidence of spatial variation and curvature in the synchrotron frequency spectrum, but there are also poorly understood multiplicative flux scale disagreements between experiments. We perform a Bayesian model comparison across a range of scenarios, using fits that include recent spectroscopic observations at $\sim 1$ GHz by MeerKAT as well as a reference map from the Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA) at 73 MHz. In the few square degrees that we analysed, a large uncorrected flux scale factor potentially as large as 1.6 in the Haslam data is preferred, indicating a 60 per cent overestimation of the brightness. This partly undermines its use as a reference map. We also find that models with non-zero spectral curvature are statistically disfavoured. Given the limited sky coverage here, we suggest a similar analysis across many more regions of the sky to determine the extent and variation of flux scale errors, and whether they should be treated as random or systematic errors in analyses that use the Haslam map as a template.
Thomas A Baycroft; A. Santerne; A. H. M. J. Triaud; N. Heidari; Daniel Sebastian; Yasmin Davis; A. C. M. Correia; S. Lalitha; Alix Violet Freckelton; Aleyna Adamson; Isabelle Boisse; Gavin A. L. Coleman; Georgina Dransfield; J. P. Faria; S. Grouffal; N. Hara; Guillaume Hébrard; Vedad Kunovac; David V. Martin; P. F. L. Maxted; Richard P. Nelson; M. G. Scott; Owen J Scutt; Matthew R. Standing
Monthly Notices of the Royal Astronomical Society · DOI
ABSTRACT Planetary systems orbiting close binaries are valuable testing grounds for planet formation and migration models. More detections with good mass measurements are needed. We present a new planet discovered during the BEBOP survey for circumbinary exoplanets using radial velocities. We use data taken with the SOPHIE spectrograph at the Observatoire de Haute-Provence, and perform a spectroscopic analysis to obtain high precision radial velocities. This planet is the first radial velocity detection of a previously unknown circumbinary system. The planet has a mass of 0.56 $\rm M_{Jup}$ and orbits its host binary in 550 d with an eccentricity of 0.25. Compared to most of the previously known circumbinary planets, BEBOP-3b has a long period (relative to the binary) and a high eccentricity. There also is a candidate outer planet with a $\sim 1400$ d orbital period. We test the stability of potential further candidate signals inside the orbit of BEBOP-3b, and demonstrate that there are stable orbital solutions for planets near the instability region which is where the Kepler circumbinary planets are located. We also use our data to obtain independent dynamical masses for the two stellar components of the eclipsing binary using high resolution cross-correlation spectroscopy, and compare those results to a more traditional approach, finding them compatible with one another.
Dario Bressan; N. A. Walton; Gregory J. Hannon; Mohammad Al Sa’d; Bruno Albuquerque; Hamid Raza Ali; Martina Alini; Samuel Aparício; Heather Ashmore; Thomas J. Ashmore; et al.
Cancer Discovery · DOI
The Imaging and Molecular Annotation of Xenografts and Tumors Cancer Grand Challenges team was set up with the objective of developing the "next generation" of pathology and cancer research by using a combination of single-cell and spatial omics tools to produce 3D molecularly annotated maps of tumors. Its activities overlapped, and in some cases catalyzed, a spatial revolution in biology that saw new technologies being deployed to investigate the roles of tumor heterogeneity and of the tumor micro-environment. See related article by Stratton et al., p. 22 See related article by Bhattacharjee et al., p. 28 See related article by Goodwin et al., p. 34.
Leigh C. Smith; Saad Ahmed; F. De Angeli; P. W. Burgess; G. Busso; Dominic Ford; D. L. Harrison; S. T. Hodgkin; Jonathan Irwin; Guy Rixon; N. A. Walton
Monthly Notices of the Royal Astronomical Society · DOI
ABSTRACT We present the Cambridge Exoplanet Transit Recovery Algorithm (cetra), a fast and sensitive transit detection algorithm, optimized for GPUs. cetra separates the task into a search for transit signals across linear time space, followed by a phase-folding of the former to enable a periodic signal search, using a physically motivated transit model to improve detection sensitivity. It outperforms traditional methods like Box Least Squares and Transit Least Squares in both sensitivity and speed. Tests on synthetic light curves demonstrate that cetra can identify at least 20 per cent more low-SNR transits than Transit Least Squares in the same data, particularly those of long period planets. It is also shown to be up to a few orders of magnitude faster for high cadence light curves, enabling rapid large-scale searches. Through application of cetra to Transiting Exoplanet Survey Satellite short cadence data, we recover the three planets in the HD 101581 system with improved significance. In particular, the transit signal of the previously unvalidated planet TOI-6276.03 is enhanced from ${\rm SNR}=7.9$ to ${\rm SNR}=16.0$, which means it may now meet the criteria for statistical validation. cetra’s speed and sensitivity make it well-suited for current and future exoplanet surveys, particularly in the search for Earth analogues. Our implementation of this algorithm uses NVIDIA’s CUDA platform and requires an NVIDIA GPU, it is open-source and available from GitHub and PyPI.
S. Lalitha; Nikku Madhusudhan
Monthly Notices of the Royal Astronomical Society · DOI
ABSTRACT Planetary systems orbiting M dwarf host stars are promising targets for atmospheric characterization of low-mass exoplanets. Accurate characterization of M dwarf hosts is important for detailed understanding of the planetary properties and physical processes, including potential habitability. Recent studies have identified several candidate Hycean planets orbiting nearby M dwarfs as promising targets in the search for habitability and life on exoplanets. In this study, we characterize two such M dwarf host stars, K2-18 and TOI-732. Using archival photometric and spectroscopic observations, we estimate their effective temperatures ($T_{\mathrm{eff}}$) and metallicities through high-resolution spectral analyses and ages through gyrochronology. We assess the stellar activity of the targets by analysing activity-sensitive chromospheric lines and X-ray luminosities. Additionally, we predict activity cycles based on measured rotation periods and utilize photometric data to estimate the current stellar activity phase. We find K2-18 to be 2.9–3.1 Gyr old with $T_{\mathrm{eff}}$ = 3645 $\pm$ 52 K and metallicity of [Fe/H] = 0.10 $\pm$ 0.12 dex, and TOI-732 to be older (6.7–8.6 Gyr), cooler (3213 $\pm$ 92 K), and more metal-rich ([Fe/H] = 0.22 $\pm$ 0.13 dex). Both stars exhibit relatively low activity making them favourable for atmospheric observations of their planets. The predicted activity cycle and analysis of available high-precision photometry for K2-18 suggest that it might have been near an activity minimum during recent JWST observations, though some residual activity may be expected at such minima. We predict potential activity levels for both targets to aid future observations and highlight the importance of accurate characterization of M dwarf host stars for exoplanet characterization.
Tristan Whitmarsh
JBMR Plus · DOI
3D-DXA, as implemented in the software tool 3D-Shaper, is a software method that generates a 3D reconstruction of the proximal femur from a single 2D DXA image by registering a statistical model. Implementations of 3D-DXA aim to provide estimates of trabecular, cortical, and structural parameters, similar to those derived from quantitative computed tomography (QCT). As the inventor and developer of the software methods upon which 3D-DXA is built, I have been observing its adoption and widespread use with increasing concern. This article provides a critical evaluation of the methodological limitations inherent to 3D-DXA and discusses their implications for research and patient care. The primary issue is that the limited visibility of the cortex in a DXA image prevents 3D-DXA from accurately deriving cortical parameters. Instead, the software relies on predictions based on overall BMD rather than direct cortical measurements. This may lead to results that do not reflect actual cortical measurements. Additional concerns include the population bias due to the statistical model being derived from a specific demographic, and limited reconstruction accuracy by using single-view DXA images. These limitations have likely resulted in incorrect measurements and research outcomes, which have largely gone unrecognized due to the use of inappropriate performance assessment metrics and the absence of multiple comparison corrections in studies involving 3D-DXA. Despite these limitations, 3D-DXA has received regulatory approval in various countries, potentially compromising the accuracy of clinical diagnoses and treatment decisions. By highlighting these issues, this article aims to inform clinicians, researchers, and regulatory bodies about the significant limitations of 3D-DXA. It underscores the urgent need for a reevaluation of its use in research and clinical settings to prevent misinterpretation of results and to ensure patient safety.
Francine R. Marleau; Rebecca A. Habas; D. Carollo; C. Tortora; Pierre–Alain Duc; Elisabeth Sola; T. Saifollahi; M. Fügenschuh; Mike Walmsley; Raphael Zöller; et al.
Astronomy and Astrophysics · DOI
The Euclid Q1 fields were selected for calibration purposes in cosmology and are therefore relatively devoid of nearby galaxies. However, this is precisely what makes them interesting fields in which to search for dwarf galaxies in local density environments. We took advantage of the unprecedented depth, spatial resolution, and field of view of the Euclid Quick Release (Q1) to build a census of dwarf galaxies in these regions. We have identified dwarf galaxies in a representative sample of 25 contiguous tiles in the Euclid Deep Field North (EDF-N) covering an area of 14.25 deg 2 . The dwarf galaxy candidates were identified using a semi-automatic detection method based on properties measured by the Euclid pipeline and released as part of the catalogue produced by the MERge Processing Function (MER PF) pipeline. A selection cut in surface brightness and magnitude was used to produce an initial dwarf candidate catalogue, and this was followed by a cut in morphology (removing background spirals) and I E − H E colour (removing red ellipticals). This catalogue was then visually classified to produce a final sample of dwarf candidates, including their morphology, number of nuclei, globular cluster (GC) richness, and presence of a blue compact centre. We identified 2674 dwarf candidates, corresponding to 188 dwarfs per square degree. The visual classification of the dwarfs reveals a slightly uneven morphological mix of 58% ellipticals and 42% irregulars, with very few potentially GC-rich (1.0%) and nucleated (4.0%) candidates but a noticeable fraction (6.9%) of dwarfs with blue compact centres. The distance distribution of 388 (15%) of the dwarf candidates with spectroscopic redshifts peaks at about 400 Mpc. Their stellar mass distribution confirms that our selection effectively identifies dwarfs while minimising contamination. The most prominent dwarf overdensities are dominated by dwarf ellipticals, while dwarf irregulars are more evenly distributed across the field of view. This work highlights Euclid ’s remarkable ability to detect and characterise dwarf galaxies across diverse masses, distances, and environments.
Thomas A Baycroft; S. Lalitha; A. H. M. J. Triaud; A. C. M. Correia
Science Advances · DOI
One notable example of exoplanet diversity is the population of circumbinary planets, which orbit around both stars of a binary star system. There are, so far, only 16 known circumbinary exoplanets, all of which lie in the same orbital plane as the host binary. Suggestions indicate that circumbinary planets could also exist on orbits highly inclined to the binary, close to 90°, polar orbits. No such planets have been found yet, but polar circumbinary gas and debris discs have been observed, and if these were to form planets, then those would be left on a polar orbit. We report strong evidence for a polar circumbinary exoplanet, which orbits a close pair of brown dwarfs that are on an eccentric orbit. We use radial velocities to measure a retrograde apsidal precession for the binary and show that this can only be attributed to the presence of a polar planet.
Michael J. Wilensky; Melis O Irfan; Philip Bull
Accurate models of Galactic synchrotron emission are critical for our understanding of astrophysics and cosmology. For example, this emission is a bright foreground in observations of the redshifted 21-cm line and the Cosmic Microwave Background. It also serves as a probe of the astrophysical properties of our Galaxy such as its magnetic field. Galactic synchrotron emission is often modeled by anchoring to the 408 MHz Haslam map. While the map has been extensively analyzed over the past few decades and several of its known issues have been corrected, there are still uncertainties regarding the absolute calibration of the flux scale that are made apparent when compared to other maps of diffuse radio emission.
G. Riccio; Michele Cantiello; Rebecca Habas; Nandini Hazra; G. D’Ago; Gabriella Raimondo; John P. Blakeslee; Joseph B. Jensen; Marco Mirabile; E. Brocato; M. Brescia; C. M. Raiteri
Astronomy and Astrophysics · DOI
Context. The surface brightness fluctuation (SBF) method is one of the most reliable and efficient ways of measuring distances to galaxies within 100 Mpc, a matter of crucial importance for all fields of astrophysics. While recent implementations have increasingly relied on space-based observations, SBF remains effective when applied to ground-based data. In particular, deep, wide-field imaging surveys with sub-arcsecond seeing conditions allows us to make accurate SBF measurements across large samples of galaxies. With the upcoming next generation of wide-area imaging surveys, the thousands of galaxies suitable for SBF measurements will give us the opportunity to constrain the 3D structure of the local Universe. Aims. We present FAST-SBF, a new Python-based pipeline for measuring SBF, developed to support the analysis of large datasets from upcoming wide-field imaging surveys such as LSST, Euclid , and Roman . The procedure, still in the testing and development stage, is designed for automation and minimal user intervention, offering a fast and flexible approach to SBF distance estimation. Methods. We validated the performance of the procedure on high-quality imaging data from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), a precursor to LSST, analyzing a sample of both luminous early-type galaxies and fainter dwarfs. Our measurements were also compared with recent results from the Next Generation Virgo Cluster Survey (NGVS) and with the SPoT stellar population synthesis models. Results. The results show excellent agreement with published distances, with the capability of measuring the SBF signal also for faint dwarf galaxies. The pipeline allows the user to completely analyze a galaxy in relatively short time (≈ minutes) and significantly reduces the need for user intervention. The FAST-SBF tool is planned for public release to support the community in using SBF as a distance indicator in next-generation surveys.
Nick Heesters; David Chemaly; Oliver Müller; Elisabeth Sola; S. Fabbro; Ashley Ferreira; Alan W. McConnachie; Eugene A. Magnier; M. J. Hudson; K. C. Chambers; F. Hammer; Rubén Sánchez-Janssen
Astronomy and Astrophysics · DOI
The detection of low-surface-brightness galaxies beyond the Local Group poses significant observational challenges, yet these faint systems are fundamental to our understanding of dark matter, hierarchical galaxy formation, and cosmic structure. Their abundance and distribution provide crucial tests for cosmological models, particularly regarding the small-scale predictions of ΛCDM. We present a systematic detection and classification framework for unresolved dwarf galaxy candidates in the large-scale Ultraviolet Near Infrared Optical Northern Survey (UNIONS) imaging data. The main survey region covers 4861 deg2. Our pipeline preprocesses UNIONS data in three (gri) of the five bands (ugriz), including binning, artifact removal, and stellar masking before employing the software MTOBJECTS (MTO) to detect low-surface-brightness objects. Following a set of parameter cuts using known dwarf galaxies from the literature and cross-matching between the three bands, we were left with an average of ∼360 candidates per deg2. With ∼4000 deg2 in g, r and i, this amounts to ∼1.5 million candidates that form our GOBLIN (Galaxies OBserved as Low-luminosity Identified Nebulae) catalog. For the final classification of these candidates, we finetuned the deep learning model ZOOBOT, which was pretrained based on labels from the Galaxy Zoo project. We created our training dataset by visually inspecting dwarf galaxy candidates from existing literature catalogs within our survey area and assigning probability labels based on averaged expert assessments. This approach captures both consensus and uncertainty among experts. When applied to all detected MTO objects, our method identified 42 965 dwarf galaxy candidates with probability scores of >0.8, of which 23 072 have probabilities exceeding 0.9. The spatial distribution of high-probability candidates reveals a correlation with the locations of massive galaxies (log (M∗/M⊙)≥ 10) within 120 Mpc. While some of these objects may have been previously identified in other surveys, we present this extensive catalog of candidates, including their positions, structural parameter estimates, and classification probabilities, as a resource for the community to enable studies of galaxy formation, evolution, and the distribution of dwarf galaxies in different environments.
Isabella P. Carucci; José L Bernal; Steven Cunnington; Mário G. Santos; Jingying Wang; José Fonseca; Keith Grainge; Melis O Irfan; Yichao Li; Alkistis Pourtsidou; Marta Spinelli; Laura Wolz
Astronomy and Astrophysics · DOI
Removing contaminants is a delicate, yet crucial step in neutral hydrogen (H I ) intensity mapping and often considered the technique’s greatest challenge. Here, we address this challenge by analysing H I intensity maps of about 100 deg 2 at redshift z ≈ 0.4 collected by the MeerKAT radio telescope, an SKA Observatory (SKAO) precursor, with a combined 10.5-hour observation. Using unsupervised statistical methods, we removed the contaminating foreground emission and systematically tested, step-by-step, some common pre-processing choices to facilitate the cleaning process. We also introduced and tested a novel multiscale approach: the data were redundantly decomposed into subsets referring to different spatial scales (large and small), where the cleaning procedure was performed independently. We confirm the detection of the H I cosmological signal in cross-correlation with an ancillary galactic data set, without the need to correct for signal loss. In the best set-up we achieved, we were able to constrain the H I distribution through the combination of its cosmic abundance (Ω H I ) and linear clustering bias ( b H I ) up to a cross-correlation coefficient ( r ). We measured Ω H I b H I r = [0.93 ± 0.17] × 10 −3 with a ≈6 σ confidence, which is independent of scale cuts at both edges of the probed scale range (0.04 ≲ k ≲ 0.3 h Mpc −1 ), corroborating its robustness. Our new pipeline has successfully found an optimal compromise in separating contaminants without incurring a catastrophic signal loss. This development instills an added degree of confidence in the outstanding science we can deliver with MeerKAT on the path towards H I intensity mapping surveys with the full SKAO.
Ian Selby; E. González-Solares; Anna Breger; Michael Roberts; Lorena Escudero Sánchez; James H.F. Rudd; Nicholas Walton; Judith Babar; Carola‐Bibiane Schönlieb; Evis Sala; Jonathan Weir‐McCall
The Royal College of Radiologists Open · DOI
C. Tortora; G. Tozzi; Guido Agapito; F. La Barbera; Chiara Spiniello; Rui Li; Giulia Carlà; G. D’Ago; Essna Ghose; F. Mannucci; N. R. Napolitano; Enrico Pinna; M. Arnaboldi; Davide Bevacqua; Anna Ferré-Mateu; Anna Gallazzi; Johanna Hartke; L. K. Hunt; Michalina Maksymowicz-Maciata; C. Pulsoni; P. Saracco; Diana Scognamiglio; Marilena Spavone
Monthly Notices of the Royal Astronomical Society · DOI
ABSTRACT Relics are massive, compact and quiescent galaxies that assembled the majority of their stars in the early Universe and lived untouched until today, completely missing any subsequent size growth caused by mergers and interactions. They provide the unique opportunity to put constraints on the first phase of mass assembly in the Universe with the ease of being nearby. While only a few relics have been found in the local Universe, the INSPIRE project has confirmed 38 relics at higher redshifts ($z \sim 0.2{\small --}0.4$), fully characterizing their integrated kinematics and stellar populations. However, given the very small sizes of these objects and the limitations imposed by the atmosphere, structural parameters inferred from ground-based optical imaging are possibly affected by systematic effects that are difficult to quantify. In this paper, we present the first high-resolution image obtained with Adaptive Optics Ks-band observations on SOUL-LUCI@LBT of one of the most extreme INSPIRE relics, KiDS J0842 + 0059 at $z \sim 0.3$. We confirm the discy morphology of this galaxy (axis ratio of 0.24) and its compact nature (circularized effective radius of $\sim 1$ kpc) by modelling its 2D surface brightness profile with a point-spread function-convolved Sérsic model. We demonstrate that the surface mass density profile of KiDS J0842 + 0059 closely resembles that of the most extreme local relic, NGC 1277, as well as of high-redshift red nuggets. We unambiguously conclude that this object is a remnant of a high-redshift compact and massive galaxy, which assembled all of its mass at $z>2$, and completely missed the merger phase of the galaxy evolution at high redshift.
Charles Yin; A. Lawrence; M. J. Ward; D. Homan; W. Kollatschny
Monthly Notices of the Royal Astronomical Society · DOI
ABSTRACT We present flux measurements of the coronal lines [Fe vii] and [Fe x] spanning three decades, in the highly variable active galactic nucleus (AGN) MKN 110. These coronal lines are sensitive to the spectral energy distribution of AGNs in the extreme ultraviolet. Neither [Fe vii] nor [Fe x] demonstrates variability in the short term on a weekly or monthly time-scale. However, by taking advantage of a long-term decrease in the continuum flux of MKN 110 of the order of years, we were able to track the [Fe vii] and [Fe x] fluxes as they respond to the continuum. We were able to detect a lag for [Fe vii] relative to the continuum at 5100 Å, with a modal lag of 652 d, but were unable to detect a significant lag in the [Fe x] flux, though there exist significant uncertainties in the [Fe x] fit. These two lag results are not consistent and the line widths for the two line species also do not match. This provides strong evidence for stratification within the coronal line region (CLR). There is also evidence of a non-varying component within the coronal line flux, probably a result of a more extended region of origin. Taken together, these results suggest a CLR where the bulk of the [Fe vii] originates on parsec scales, but a portion of the [Fe vii] flux originates further out, at or beyond a 10 pc scale. These results also indicate the limitations of single-cloud models in describing the physical conditions of the CLR.
Johanna Hartke; E. Iodice; M. Gullieuszik; Marco Mirabile; Chiara Buttitta; Goran Doll; G. D’Ago; C.C. de la Casa; Kelley M. Hess; Ralf Kotulla; Bianca M. Poggianti; M. Arnaboldi; M. Cantiello; E. M. Corsini; J. Falcón-Barroso; Duncan A. Forbes; M. Hilker; S. Mieske; M. Rejkuba; M. Spavone; C. Spiniello
Astronomy and Astrophysics · DOI
Context. UDG 32 is an ultra-diffuse galaxy (UDG) candidate in the Hydra I cluster that was discovered in the extended network of stellar filaments of the jellyfish galaxy NGC 3314A. This jellyfish galaxy is affected by ram pressure stripping and it is hypothesised that UDG 32 may have formed from this stripped material. Aims. The aim of this paper is to address whether UDG 32 can be associated with the stripped material of NGC 3314A and to constrain its formation scenario in relation to its environment. Methods. We use new integral-field spectroscopic data from the MUSE large programme ‘LEWIS’ in conjunction with deep multi-band photometry to constrain the kinematics of UDG 32 via spectral fitting and its stellar population properties with spectral energy distribution fitting. Results. The new MUSE data allow us to reveal that the stripped material from NGC 3314A, traced by emission lines such as H α , extends much further from its parent galaxy than previously known, completely overlapping with UDG 32 in projection, and with ram pressure induced star formation. We determine the line-of-sight velocity of UDG 32 to be v LOS = 3080 ± 120 km s −1 and confirm that UDG 32 is part of the same kinematic structure as NGC 3314A, the Hydra I cluster south-east subgroup. By fitting the UV and optical spectral energy distribution obtained from deep multi-band photometry, we constrain the stellar population properties of UDG 32. We determine its mass-weighted age to be 7.7 −2.8 +2.9 Gyr and its metallicity to be [M/H] = 0.07 −0.32 +0.19 dex. We confirm the presence of two globular clusters (GCs) in the MUSE field of view, bound to the Hydra I cluster rather than to UDG 32, making them part of the Hydra I intracluster GC population. Conclusions. The metal-rich and intermediate-age nature of UDG 32 points towards its formation from pre-enriched material in the south-east group of the Hydra I cluster that was liberated from a more massive galaxy via tidal or ram-pressure stripping, but we cannot establish a direct link to the ram-pressure stripped material from NGC 3314A.
Johanna Hartke; E. Iodice; Marco Gullieuszik; Marco Mirabile; Chiara Buttitta; Goran Doll; G. D’Ago; C.C. de la Casa; Kelley M. Hess; Ralf Kotulla; Bianca Maria Poggianti; M. Arnaboldi; Matteo Cantiello; E. M. Corsini; J. Falcón-Barroso; D. A. Forbes; M. Hilker; S. Mieske; M. Rejkuba; Marilena Spavone; C. Spiniello
arXiv (Cornell University) · DOI
UDG 32 is an ultra-diffuse galaxy (UDG) candidate in the Hydra I cluster that was discovered in the extended network of stellar filaments of the jellyfish galaxy NGC 3314A. This galaxy is affected by ram pressure stripping and it is hypothesised that UDG 32 may have formed from its stripped material. In this paper, we address whether UDG 32 can be associated with the stripped material of NGC 3314A and constrain its formation scenario in relation to its environment. We use new integral-field spectroscopic data from the MUSE large programme `LEWIS' in conjunction with deep multi-band photometry to constrain the kinematics and stellar populations of UDG 32. The new MUSE data allow us to reveal that the stripped material from NGC 3314A, traced by emission lines such as H$α$, extends much further from its parent galaxy than previously known, completely overlapping with UDG 32 in projection, and with ram pressure induced star formation. We determine the line-of-sight velocity of UDG 32 ($v_{\rm LOS} = 3080\pm120$ km/s) and confirm that UDG 32 is part of the same kinematic structure as NGC 3314A, the Hydra I cluster south-east subgroup. By fitting the UV and optical spectral energy distribution, we constrain the stellar population properties of UDG 32. We determine its mass-weighted age to be $7.7^{+2.9}_{-2.8}$ Gyr and its metallicity to be [M/H] = $0.07^{+0.19}_{-0.32}$ dex. We confirm the presence of two globular clusters (GCs) in the MUSE field of view, bound to the Hydra I cluster rather than to UDG 32, thus part of the Hydra I intracluster GC population. The metal-rich and intermediate-age nature of UDG 32 points towards its formation from pre-enriched material in the south-east group of the Hydra I cluster that was liberated from a more massive galaxy via tidal or ram-pressure stripping, but we cannot establish a direct link to the ram-pressure stripped material from NGC 3314A.
Elisabeth Sola; Pierre–Alain Duc; M Urbano; Felix Richards; Adeline Paiement; Michal Bílek; Mustafa K. Yıldız; A. Boselli; P. Côté; Jean‐Charles Cuillandre; Laura Ferrarese; Stephen Gwyn; O. Marchal; Alan W. McConnachie; Matthieu Baumann; T. Boch; F. Durret; Matteo Fossati; Rebecca A. Habas; Francine R. Marleau; Oliver Müller; Mélina Poulain; Vasily A Belokurov
Monthly Notices of the Royal Astronomical Society · DOI
ABSTRACT Hierarchical galactic evolution models predict that mergers drive galaxy growth, producing low surface brightness (LSB) tidal features that trace galaxies’ late assembly. These faint structures encode information about past mergers and are sensitive to the properties and environment of the host galaxy. We investigated the relationships between LSB features and their hosts in a sample of 475 nearby massive galaxies spanning diverse environments (field, groups, Virgo cluster) using deep optical imaging from the Canada–France–Hawaii Telescope (MATLAS, UNIONS/CFIS, VESTIGE, NGVS). Using Jafar, an online annotation tool, we manually annotated tidal features, including 199 tidal tails and 100 streams. Geometric and photometric measurements were extracted to analyse their dependence on galaxy mass, environment, and internal kinematics. At our surface brightness limit of 29 mag arcsec$^{-2}$, tidal features contribute 2 per cent of total galaxy luminosity. They are detected in 36 per cent of galaxies, with none fainter than 27.8 mag arcsec$^{-2}$. The most massive galaxies are twice as likely to host tidal debris. Although small-scale interactions increase the frequency of tidal features, the large-scale environment (Virgo cluster versus field/group) does not influence it. An anticorrelation between this frequency and rotational support is found, but may reflect the mass-driven effect. We release our data base of annotated features for deep learning applications. Our findings confirm that galaxy mass is the dominant factor influencing tidal feature prevalence, consistent with hierarchical formation models.
Chloé Padois; Daniel del Ser; Friedrich Anders; João A. S. Amarante; D. Hélio Perottoni; Thomas Hajnik; Diogo Souto; I. Nayara Feliciano-Souza; Daisuke Kawata; Eder Martioli
Astronomy and Astrophysics · DOI
Context . Exoplanet transit and radial-velocity surveys have allowed us to explore the exoplanet population in our Galactic surroundings. The planet populations in more remote areas of the Milky Way (MW) will become accessible with future instrumentation. Aims . In this paper, we aim to simulate realistic exoplanet populations across different regions of the MW by combining state-of-the-art cosmological simulations of our Galaxy with exoplanet formation models and observations. Methods . We model the exoplanet populations around simulated single stars, using planet occurrence rate and multiplicity depending on stellar mass, metallicity, and planet type, and assign them physical parameters such as mass and orbital period. Results . Focussing first on the solar vicinity, we find mostly metallicity-driven differences in the distributions of non-hosting and planet-hosting single stars. In our simulated solar neighbourhood, 52.5% of all planets are Earth-like (23% of them located in the Habitable Zone), 44% are super-Earths or Neptunes, and 3.5% are giant planets. A detailed comparison with the census of Kepler exoplanets and candidates shows that, when taking into account the most relevant selection effects, we obtain a similar distribution of exoplanets compared to the observed population. However, we also detect some significant differences in the exoplanet and host star distributions (e.g. more planets around F-type and red-giant stars compared to the observations) that we attribute mostly to a too strong recent star formation and a too large disc scale height in the simulation compared to the solar neighbourhood, as well as to some caveats in our exoplanet population synthesis that will be addressed in future work. Extending our analysis to other regions of the simulated MW and to other galaxies within the same suite of simulations, we find that the relative percentages of Earth-like, super-Earth or Neptunes, and giant planets remain largely consistent as long as the simulated galaxy matches the morphology and mass of the MW. Conclusions . We have created a fast and flexible framework to produce exoplanet populations based on MW-like simulations that can easily be adapted to produce predictions for the yields of future exoplanet detection missions.