bluuebunny/crossref_metadata_2025_split huggingface dataset:
FRB 20210405I: a nearby Fast Radio Burst localized to sub-arcsecond precision with MeerKAT
Authors: Driessen L N , Barr E D , Buckley D A H , Caleb M , Chen H , Chen W , Gromadzki M , Jankowski F , Kraan-Korteweg R C , Palmerio J , Rajwade K M , Tremou E , Kramer M , Stappers B W , Vergani S D , Woudt P A , Bezuidenhout M C , Malenta M , Morello V , Sanidas S , Surnis M P , Fender R P 
Published: November 2023

ABSTRACT
We present the first sub-arcsecond localized Fast Radio Burst (FRB) detected using MeerKAT. FRB 20210405I was detected in the incoherent beam using the MeerTRAP pipeline on 2021 April 05 with a signal to noise ratio of 140.8 and a dispersion measure of 565.17 pc cm−3. It was detected while MeerTRAP was observing commensally with the ThunderKAT large survey project, and was sufficiently bright that we could use the ThunderKAT 8 s images to localize the FRB. Two different models of the dispersion measure in the Milky Way and halo suggest that the source is either right at the edge of the Galaxy, or outside. This highlights the uncertainty in the Milky Way dispersion measure models, particularly in the Galactic Plane, and the uncertainty of Milky Way halo models. Further investigation and modelling of these uncertainties will be facilitated by future detections and localizations of nearby FRBs. We use the combined localization, dispersion measure, scattering, specific luminosity, and chance coincidence probability information to find that the origin is most likely extra-galactic and identify the likely host galaxy of the FRB: 2MASS J1701249−4932475. Using SALT spectroscopy and archival observations of the field, we find that the host is a disc/spiral galaxy at a redshift of z = 0.066.
Single pulse polarization study of pulsars B0950 + 08 and B1642 − 03: micropulse properties and mixing of orthogonal modes
Authors: Singh Shubham , Gupta Yashwant , De Kishalay 
Published: November 2023

ABSTRACT
We present the results of a high-time resolution polarization study of single pulses from pulsars B0950 + 08 and B1642 − 03. Single pulses from pulsar B0950 + 08 sometimes show isolated micropulses without any significant associated subpulse emission. Assuming that the properties of such micropulses represent the intrinsic nature of micropulse emission, we characterize the width and polarization properties of these ‘intrinsic’ microstructures. Most of the ‘intrinsic’ micropulses ($\sim 90~{{\ \rm per\ cent}}$) follow common characteristic polarization properties, while the average width of these micropulses is consistent with the general micropulse population from this pulsar. Single pulses from these pulsars show a diverse range of polarization properties, including depolarization and mixing of two orthogonal modes resulting in polarization position angle jumps. We present a superposition model of the two orthogonal modes which can explain depolarization, the observed position angle jumps, and associated changes in other polarization parameters.
Continuous gravitational waves from trapped magnetar ejecta and the connection to glitches and antiglitches
Authors: Yim Garvin , Gao Yong , Kang Yacheng , Shao Lijing , Xu Renxin 
Published: November 2023

ABSTRACT
Gravitational waves from isolated sources have eluded detection so far. The upper limit of long-lasting continuous gravitational wave emission can now probe physically motivated models with the most optimistic being strongly constrained. Naturally, one might want to relax the assumption of the gravitational wave being quasi-infinite in duration, leading to the idea of transient continuous gravitational waves. In this paper, we outline how to get transient continuous waves from magnetars (or strongly magnetized neutron stars) that exhibit glitches and/or antiglitches and apply the model to magnetar SGR 1935+2154. The toy model hypothesizes that at a glitch or antiglitch, mass is ejected from the magnetar but becomes trapped on its outward journey through the magnetosphere. Depending on the height of the trapped ejecta and the magnetic inclination angle, we are able to reproduce both glitches and antiglitches from simple angular momentum arguments. The trapped ejecta causes the magnetar to precess leading to gravitational wave emission at once and twice the magnetar’s spin frequency, for a duration equal to however long the ejecta is trapped for. We find that the gravitational waves are more detectable when the magnetar is: closer, rotating faster, or has larger glitches/antiglitches. The detectability also improves when the ejecta height and magnetic inclination angle have values near their critical values, though this requires more mass to be ejected to remain consistent with the observed glitch/antiglitch. We find it unlikely that gravitational waves will be detected from SGR 1935+2154 when using the trapped ejecta model.
Identifying the discs, bulges, and intra-halo light of simulated galaxies through structural decomposition
Authors: Proctor Katy L , Lagos Claudia del P , Ludlow Aaron D , Robotham Aaron S G 
Published: November 2023

ABSTRACT
We perform a structural decomposition of galaxies identified in three cosmological hydrodynamical simulations by applying Gaussian mixture models (GMMs) to the kinematics of their stellar particles. We study the resulting disc, bulge, and intra-halo light (IHL) components of galaxies whose host dark matter haloes have virial masses in the range M200 = 1011–$10^{15}\, {\rm M_\odot }$. Our decomposition technique isolates galactic discs whose mass fractions, fdisc, correlate strongly with common alternative morphology indicators; for example, fdisc is approximately equal to κco, the fraction of stellar kinetic energy in corotation. The primary aim of our study, however, is to characterize the IHL of galaxies in a consistent manner and over a broad mass range, and to analyse its properties from the scale of galactic stellar haloes up to the intra-cluster light. Our results imply that the IHL fraction, fIHL, has appreciable scatter and is strongly correlated with galaxy morphology: at fixed stellar mass, the IHL of disc galaxies is typically older and less massive than that of spheroids. Above $M_{200}\approx 10^{13}\, {\rm M_\odot }$, we find, on average, fIHL ≈ 0.37, albeit with considerable scatter. The transition radius beyond which the IHL dominates the stellar mass of a galaxy is roughly $30\, {\rm kpc}$ for disc galaxies, but depends strongly on halo mass for spheroids. However, we find that no alternative IHL definitions – whether based on the ex situ stellar mass, or the stellar mass outside a spherical aperture – reproduce our dynamically defined IHL masses.
The e-MANTIS emulator: fast predictions of the non-linear matter power spectrum in f(R)CDM cosmology
Authors: Sáez-Casares Iñigo , Rasera Yann , Li Baojiu 
Published: November 2023

ABSTRACT
In order to probe modifications of gravity at cosmological scales, one needs accurate theoretical predictions. N-body simulations are required to explore the non-linear regime of structure formation but are very time consuming. In this work, we release a new public emulator, dubbed e-mantis, that performs an accurate and fast interpolation between the predictions of f(R) modified gravity cosmological simulations, run with ecosmog. We sample a wide 3D parameter space given by the current background scalar field value $10^{-7}\lt \left|f_{R_0}\right|\lt 10^{-4}$, matter density 0.24 &lt; Ωm &lt; 0.39, and primordial power spectrum normalization 0.6 &lt; σ8 &lt; 1.0, with 110 points sampled from a Latin hypercube. For each model we perform pairs of f(R)CDM and ΛCDM simulations covering an effective volume of $\left(560 \, h^{-1}\, \mathrm{Mpc}\right)^3$ with a mass resolution of ∼2 × 1010h−1M⊙. We build an emulator for the matter power spectrum boost B(k) = Pf(R)(k)/PΛCDM(k) using a Gaussian process regression method. The boost is mostly independent of h, ns, and Ωb, which reduces the dimensionality of the relevant cosmological parameter space. Additionally, it is more robust against statistical and systematic errors than the raw power spectrum, thus strongly reducing our computational needs. According to our dedicated study of numerical systematics, the resulting emulator has an estimated maximum error of 3 per cent across the whole cosmological parameter space, for scales $0.03 \ h\, \mathrm{Mpc}^{-1} \lt k \lt 7 \ h\, \mathrm{Mpc}^{-1}$, and redshifts 0 &lt; z &lt; 2, while in most cases the accuracy is better than 1 per cent. Such an emulator could be used to constrain f(R) gravity with weak lensing analyses.
Evidence for microlensing by primordial black holes in quasar broad emission lines
Authors: Hawkins M R S 
Published: November 2023

ABSTRACT
With the detection of black hole mergers by the LIGO gravitational wave telescope, there has been increasing interest in the possibility that dark matter may be in the form of solar mass primordial black holes. One of the predictions implicit in this idea is that compact clouds in the broad emission line regions of high-redshift quasars will be microlensed, leading to changes in line structure and the appearance of new emission features. In this paper, the effect of microlensing on the broad emission line region is reviewed by reference to gravitationally lensed quasar systems where microlensing of the emission lines can be unambiguously identified. It is then shown that although changes in Seyfert galaxy line profiles occur on time-scales of a few years, they are too nearby for a significant chance that they could be microlensed, and are plausibly attributed to intrinsic changes in line structure. In contrast, in a sample of 53 high-redshift quasars, 9 quasars show large changes in line profile at a rate consistent with microlensing. These changes occur on a time-scale an order of magnitude too short for changes associated with the dynamics of the emission line region. The main conclusion of the paper is that the observed changes in quasar emission line profiles are consistent with microlensing by a population of solar mass compact bodies making up the dark matter, although other explanations like intrinsic variability are possible. Such bodies are most plausibly identified as primordial black holes.
The MAGPI survey: effects of spiral arms on different tracers of the interstellar medium and stellar populations at z ∼ 0.3
Authors: Chen Qian-Hui , Grasha Kathryn , Battisti Andrew J , Wisnioski Emily , Mendel Trevor , Sharda Piyush , Santucci Giulia , Li Zefeng , Foster Caroline , Mun Marcie , Park Hye-Jin , Tsukui Takafumi , Sharma Gauri , Lagos Claudia D P , Barsanti Stefania , Valenzuela Lucas M , Gupta Anshu , Thater Sabine , Jin Yifei , Kewley Lisa 
Published: November 2023

ABSTRACT
Spiral structures are important drivers of the secular evolution of disc galaxies, however, the origin of spiral arms and their effects on the development of galaxies remain mysterious. In this work, we present two three-armed spiral galaxies at z ∼ 0.3 in the Middle Age Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey. Taking advantage of the high spatial resolution (∼0.6 arcsec) of the Multi-Unit Spectroscopic Explorer (MUSE), we investigate the two-dimensional (2D) distributions of different spectral parameters: Hα, gas-phase metallicity, and D4000. We notice significant offsets in Hα (∼0.2 dex) and gas-phase metallicities (∼0.05 dex) among the spiral arms, downstream and upstream of MAGPI 1202197197 (SG 1202). This observational signature suggests the spiral structure in SG 1202 is consistent with arising from density wave theory. No azimuthal variation in Hα or gas-phase metallicities is observed in MAGPI 1204198199 (SG 1204), which can be attributed to the tighter spiral arms in SG 1204 than SG 1202, coming with stronger mixing effects in the disc. The absence of azimuthal D4000 variation in both galaxies suggests the stars at different ages are well mixed between the spiral arms and distributed around the disc regions. The different azimuthal distributions in Hα and D4000 highlight the importance of time-scales traced by various spectral parameters when studying 2D distributions in spiral galaxies. This work demonstrates the feasibility of constraining spiral structures by tracing interstellar medium (ISM) and stellar population at z ∼ 0.3, with a plan to expand the study to the full MAGPI survey.
Determining the parameters of the spiral arms of the Galaxy from kinematic tracers based on Gaia DR3 data
Authors: Denyshchenko S I , Fedorov P N , Akhmetov V S , Velichko A B , Dmytrenko A M 
Published: November 2023

ABSTRACT
We present the results of determining the parameters of the spiral arms of the Galaxy using the stars Gaia DR3, whose absolute magnitude is MG &lt; 4, and which allow tracing spiral arms at large distances from the Sun. As tracers of spiral arms, we use the centroids of stellar spherical regions with a radius of 0.5 kpc, in which the deformation velocities along the coordinate axis R are insignificant. These kinematic tracers cover the Galactic plane within the Galactocentric coordinate ranges 140° &lt; θ &lt; 220° and 4 kpc &lt; R &lt; 14 kpc. The numerical values of the pitch angles of the spirals and their Galactocentric distances to the point of intersection of the spiral with the direction of the Galactic Centre and the Sun are in good agreement with the results of other authors. By extrapolating beyond the data we have, we present a schematic four-arm global pattern, consisting of the Scutum–Centaurus, Sagittarius–Carina, Perseus, Norma-Outer arms, as well as the local arm Orion. The uncertainties of the determined spiral parameters confirm that the structures identified are not false, but are reliable from the statistical point of view.
TransitFit: combined multi-instrument exoplanet transit fitting for JWST, HST, and ground-based transmission spectroscopy studies
Authors: Hayes J J C , Priyadarshi A , Kerins E , Awiphan S , McDonald I , A-thano N , Morgan J S , Humpage A , Charles S , Wright M , Joshi Y C , Jiang Ing-Guey , Inyanya T , Padjaroen T , Munsaket P , Chuanraksasat P , Komonjinda S , Kittara P , Dhillon V S , Marsh T R , Reichart D E , Poshyachinda S ,   (The SPEARNET Collaboration)
Published: November 2023

ABSTRACT
We present transitfit1, a package designed to fit exoplanetary transit light curves. transitfit offers multi-epoch, multi-wavelength fitting of multi-telescope transit data. transitfit allows per-telescope detrending to be performed simultaneously with transit parameter fitting, including custom detrending. Host limb darkening can be fitted using prior conditioning from stellar atmosphere models. We demonstrate transitfit in a number of contexts. We model multi-telescope broad-band optical data from the ground-based SPEARNET survey of the low-density hot-Neptune WASP-127b and compare results to a previously published higher spectral resolution GTC/OSIRIS transmission spectrum. Using transitfit, we fit 26 transit epochs by TESS to recover improved ephemeris of the hot-Jupiter WASP-91b and a transit depth determined to a precision of 111 ppm. We use transitfit to conduct an investigation into the contested presence of TTV signatures in WASP-126b using 180 transits observed by TESS, concluding that there is no statistically significant evidence for such signatures from observations spanning 27 TESS sectors. We fit HST observations of WASP-43 b, demonstrating how transitfit can use custom detrending algorithms to remove complex baseline systematics. Lastly, we present a transmission spectrum of the atmosphere of WASP-96b constructed from simultaneous fitting of JWST NIRISS Early Release Observations and archive HST WFC3 transit data. The transmission spectrum shows generally good correspondence between spectral features present in both data sets, despite very different detrending requirements.
SRG/eROSITA catalogue of X-ray active SDSS dwarf galaxies
Authors: Bykov S D , Gilfanov M R , Sunyaev R A 
Published: November 2023

ABSTRACT
We present a sample of 99 dwarf galaxies (M* &lt; 109.5 M⊙) with X-ray activity in their central regions. The sample was obtained from a match of the SRG/eROSITA X-ray catalogue in the eastern galactic hemisphere with the MPA-JHU SDSS catalogue. The obtained matches were cleaned rigorously with the help of external optical catalogues to increase the purity of the sample. This work is the largest study of this kind – X-ray activity in ≈85 per cent of matched dwarfs was not reported before. The majority of X-ray active dwarfs are identified as star-forming galaxies. However, the X-ray luminosity of 82 objects cannot be explained by the collective emission of X-ray binaries, rendering them strong candidates for dwarf galaxies with an active accreting black hole in their centre. We find that the fraction of AGN among dwarf galaxies drops from ∼2 · 10−2 at LX ∼ 1039 erg s–1 to ∼(2 − 4) · 10−4 at LX ∼ 1041 erg s–1 and increases with the stellar mass of the host galaxy. We serendipitously discovered sources with unexpected properties. We report on a tidal disruption event (TDE) candidate in a dwarf galaxy, a massive black hole in a dwarf galaxy with a soft thermal spectrum, a luminous dwarf galaxy with an obscured X-ray spectrum and a few other peculiar sources. We found three Ultra-luminous X-ray (ULX) source candidates and a sample of X-ray bright galaxy pairs, in four of which both members shine in X-rays.
A clustering (DBSCAN+GMM) investigation of the young open cluster NGC 6649
Authors: Gao Xinhua 
Published: November 2023

ABSTRACT
We investigate the spatial structure and dynamical properties of the young (∼60 Myr), richly populated open cluster NGC 6649 based on reliable cluster members from Gaia-DR3 data. The density-based spatial clustering of applications with noise is used to estimate membership probabilities for 25045 sample stars in the field of the cluster. More than 1000 likely cluster members down to G ∼ 20 mag can be identified based on the membership probabilities. The cluster members of NGC 6649 extend up to a radial distance of ${\sim} 21\,\mathrm{ arcmin}$ (12 pc), which is much larger than previously thought. We estimate a core radius of $R_{\mathrm{ c}}=2\overset{^{\prime }}{.}38\pm 0\overset{^{\prime }}{.}06$ (1.4 pc) and a tidal radius of $R_{\mathrm{ t}}=35\overset{^{\prime }}{.}85\pm 6\overset{^{\prime }}{.}64$ (20.9 pc) for the cluster, indicating that the cluster has formed a dense core and an extended halo. We find that mass segregation has taken place within the cluster. We also detect two small and sparse clusters (C1 and C2) around NGC 6649. C1 has recently been reported, but C2 is detected for the first time. The Gaussian mixture model clustering method is used to identify 184 and 60 members for C1 and C2, respectively. We find that NGC 6649, C1, and C2 are located at similar distances. Moreover, we estimate a small spatial separation of ∼11.6 pc between C1 and NGC 6649, which is close to or slightly smaller than the detectable radius of NGC 6649. This indicates that NGC 6649 and C1 are physically connected, and there may exist strong tidal interactions and mass transfer between the two clusters. C2 shows a significant lack of faint members (G &gt; 17 mag), probably due to star evaporation and tidal stripping. Our results show that NGC 6649 may be the dominant cluster in a triple-cluster system (NGC 6649+C1+C2).
Solving the inverse cosmological calibration problem of gamma-ray bursts
Authors: Shirokov S I , Gainutdinov R I , Lovyagin N Yu , Gorokhov V L 
Published: November 2023

ABSTRACT
We have received a new physical characteristics fitting based on actual observational data from the Swift mission’s long-duration gamma-ray bursts (LGRBs). We considered such characteristics as the Amati parameters for linear correlation (Eiso–Ep,i) and the k-correction for gravitational lensing and Malmquist bias (GLMB) effect. We used the Pantheon SN Ia catalogue and the standard Lambda cold dark matter model with a fixed Hubble constant of H0 = 70 km s−1 Mpc−1 as the baseline for the Hubble function μ(z). In our paper, we formulated the inverse cosmological calibration problem (ICCP) in the non-parametric statistics framework. The ICCP involves fitting non-observable physical characteristics while assuming a fixed cosmological model. To solve this problem, we developed a new method that is resistant to non-Gaussian processes. This method is based on error propagation through the Monte Carlo method and the Theil–Sen method for linear regression estimate. We have demonstrated the stability and robustness of this assessment method. The parameter estimates are as follows: $a=0.92^{+0.12}_{-0.12}$, $b=50.32^{+0.33}_{-0.32}$ without considering the GLMB effect, and $a=0.63^{+0.13}_{-0.14}$, $b=50.12^{+0.33}_{-0.31}$, and $k=1.98^{+0.25}_{-0.24}$ with the effect included. The proposed method can be applied to any other calibration sample of known standard candles, a calibrated sample of LGRBs, and the Hubble function μ(z). In the future, the ICCP idea can be used as an alternative cosmological test for estimating cosmological parameters, including the GLMB effect, or even for the selection of models, providing new information about the Universe. This can be done by analysing the residual values of observational data within the Bayesian statistics paradigm.
CAvity DEtection Tool (CADET): pipeline for detection of X-ray cavities in hot galactic and cluster atmospheres
Authors: Plšek T , Werner N , Topinka M , Simionescu A 
Published: November 2023

ABSTRACT
The study of jet-inflated X-ray cavities provides a powerful insight into the energetics of hot galactic atmospheres and radio-mechanical AGN feedback. By estimating the volumes of X-ray cavities, the total energy and thus also the corresponding mechanical jet power required for their inflation can be derived. Properly estimating their total extent is, however, non-trivial, prone to biases, nearly impossible for poor-quality data, and so far has been done manually by scientists. We present a novel machine-learning pipeline called Cavity Detection Tool (CADET), developed as an assistive tool that detects and estimates the sizes of X-ray cavities from raw Chandra images. The pipeline consists of a convolutional neural network trained for producing pixel-wise cavity predictions and a DBSCAN clustering algorithm, which decomposes the predictions into individual cavities. The convolutional network was trained using mock observations of early-type galaxies simulated to resemble real noisy Chandra-like images. The network’s performance has been tested on simulated data obtaining an average cavity volume error of 14 per cent at an 89 per cent true-positive rate. For simulated images without any X-ray cavities inserted, we obtain a 5 per cent false-positive rate. When applied to real Chandra images, the pipeline recovered 93 out of 97 previously known X-ray cavities in nearby early-type galaxies and all 14 cavities in chosen galaxy clusters. Besides that, the CADET pipeline discovered seven new cavity pairs in atmospheres of early-type galaxies (IC 4765, NGC 533, NGC 2300, NGC 3091, NGC 4073, NGC 4125, and NGC 5129) and a number of potential cavity candidates.