bluuebunny/crossref_metadata_2025_split huggingface dataset:
Collimation of the kiloparsec-scale radio jets in NGC 2663
Authors: Velović Velibor , Filipović M D , Barnes L , Norris R P , Tremblay C D , Heald G , Rudnick L , Shabala S S , Pannuti T G , Andernach H , Titov O , Waddell S G H , Koribalski B S , Grupe D , Jarrett T , Alsaberi R Z E , Carretti E , Collier J D , Einecke S , Galvin T J , Hotan A , Manojlović P , Marvil J , Nandra K , Reiprich T H , Rowell G , Salvato M , Whiting M 
Published: September 2022

ABSTRACT
We present the discovery of highly collimated radio jets spanning a total of 355 kpc around the nearby elliptical galaxy NGC 2663, and the possible first detection of recollimation on kiloparsec scales. The small distance to the galaxy (∼28.5 Mpc) allows us to resolve portions of the jets to examine their structure. We combine multiwavelength data: radio observations by the Murchison Widefield Array (MWA), the Australian Square Kilometre Array Pathfinder (ASKAP) and the Australia Telescope Compact Array (ATCA), and X-ray data from Chandra, Swift, and SRG/eROSITA. We present intensity, rotation measure, polarization, spectral index, and X-ray environment maps. Regions of the southern jet show simultaneous narrowing and brightening, which can be interpreted as a signature of the recollimation of the jet by external, environmental pressure, though it is also consistent with intermittent active galactic nuclei or complex internal jet structure. X-ray data suggest that the environment is extremely poor; if the jet is indeed recollimating, the large recollimation scale (40 kpc) is consistent with a slow jet in a low-density environment.
The hydrogen clock to infer the upper stellar mass
Authors: Higgins Erin R , Vink Jorick S , Sabhahit Gautham N , Sander Andreas A C 
Published: September 2022

ABSTRACT
The most massive stars dominate the chemical enrichment, mechanical and radiative feedback, and energy budget of their host environments. Yet how massive stars initially form and how they evolve throughout their lives is ambiguous. The mass loss of the most massive stars remains a key unknown in stellar physics, with consequences for stellar feedback and populations. In this work, we compare grids of very massive star (VMS) models with masses ranging from 80 to 1000 M⊙, for a range of input physics. We include enhanced winds close to the Eddington limit as a comparison to standard O-star winds, with consequences for present-day observations of ∼50–100 M⊙ stars. We probe the relevant surface H abundances (Xs) to determine the key traits of VMS evolution compared to O stars. We find fundamental differences in the behaviour of our models with the enhanced-wind prescription, with a convergence on the stellar mass at 1.6 Myr, regardless of the initial mass. It turns out that Xs is an important tool in deciphering the initial mass due to the chemically homogeneous nature of VMS above a mass threshold. We use Xs to break the degeneracy of the initial masses of both components of a detached binary, and a sample of WNh stars in the Tarantula Nebula. We find that for some objects, the initial masses are unrestricted and, as such, even initial masses of the order 1000 M⊙ are not excluded. Coupled with the mass turnover at 1.6 Myr, Xs can be used as a ‘clock’ to determine the upper stellar mass.
First Light and Reionisation Epoch Simulations (FLARES) – VI. The colour evolution of galaxies z = 5–15
Authors: Wilkins Stephen M , Vijayan Aswin P , Lovell Christopher C , Roper William J , Irodotou Dimitrios , Caruana Joseph , Seeyave Louise T C , Kuusisto Jussi K , Thomas Peter A 
Published: September 2022

ABSTRACT
With its exquisite sensitivity, wavelength coverage, and spatial and spectral resolution, the James Webb Space Telescope (JWST) is poised to revolutionize our view of the distant, high-redshift (z &gt; 5) Universe. While Webb’s spectroscopic observations will be transformative for the field, photometric observations play a key role in identifying distant objects and providing more comprehensive samples than accessible to spectroscopy alone. In addition to identifying objects, photometric observations can also be used to infer physical properties and thus be used to constrain galaxy formation models. However, inferred physical properties from broad-band photometric observations, particularly in the absence of spectroscopic redshifts, often have large uncertainties. With the development of new tools for forward modelling simulations, it is now routinely possible to predict observational quantities, enabling a direct comparison with observations. With this in mind, in this work, we make predictions for the colour evolution of galaxies at z = 5–15 using the First Light And Reionisation Epoch Simulations (flares) cosmological hydrodynamical simulation suite. We predict a complex evolution with time, driven predominantly by strong nebular line emission passing through individual bands. These predictions are in good agreement with existing constraints from Hubble and Spitzer as well as some of the first results from Webb. We also contrast our predictions with other models in the literature: While the general trends are similar, we find key differences, particularly in the strength of features associated with strong nebular line emission. This suggests photometric observations alone should provide useful discriminating power between different models and physical states of galaxies.
CO2-driven surface changes in the Hapi region on Comet 67P/Churyumov–Gerasimenko
Authors: Davidsson Björn J R , Schloerb F Peter , Fornasier Sonia , Oklay Nilda , Gutiérrez Pedro J , Buratti Bonnie J , Chmielewski Artur B , Gulkis Samuel , Hofstadter Mark D , Keller H Uwe , Sierks Holger , Güttler Carsten , Küppers Michael , Rickman Hans , Choukroun Mathieu , Lee Seungwon , Lellouch Emmanuel , Lethuillier Anthony , Da Deppo Vania , Groussin Olivier , Kührt Ekkehard , Thomas Nicolas , Tubiana Cecilia , El-Maarry M Ramy , La Forgia Fiorangela , Mottola Stefano , Pajola Maurizio 
Published: September 2022

ABSTRACT
Between 2014 December 31 and 2015 March 17, the OSIRIS cameras on Rosetta documented the growth of a $140\, \mathrm{\hbox{-}m}$ wide and $0.5\, \mathrm{\hbox{-}m}$ deep depression in the Hapi region on Comet 67P/Churyumov–Gerasimenko. This shallow pit is one of several that later formed elsewhere on the comet, all in smooth terrain that primarily is the result of airfall of coma particles. We have compiled observations of this region in Hapi by the microwave instrument MIRO on Rosetta, acquired during October and November 2014. We use thermophysical and radiative transfer models in order to reproduce the MIRO observations. This allows us to place constraints on the thermal inertia, diffusivity, chemical composition, stratification, extinction coefficients, and scattering properties of the surface material, and how they evolved during the months prior to pit formation. The results are placed in context through long-term comet nucleus evolution modelling. We propose that (1) MIRO observes signatures that are consistent with a solid-state greenhouse effect in airfall material; (2) CO2 ice is sufficiently close to the surface to have a measurable effect on MIRO antenna temperatures, and likely is responsible for the pit formation in Hapi observed by OSIRIS; (3) the pressure at the CO2 sublimation front is sufficiently strong to expel dust and water ice outwards, and to compress comet material inwards, thereby causing the near-surface compaction observed by CONSERT, SESAME, and groundbased radar, manifested as the ‘consolidated terrain’ texture observed by OSIRIS.
A universal profile for stacked filaments from cold dark matter simulations
Authors: Yang Tianyi , Hudson Michael J , Afshordi Niayesh 
Published: September 2022

ABSTRACT
We study the stacked filaments connecting group-mass halo pairs, using dark-matter-only N-body simulations. We calculate the dark matter overdensity profile of these stacked filaments at different redshifts as a function of the distance perpendicular to the filament axis. A four-parameter universal functional form, including three comoving scale radii and one amplitude parameter (core density), provides a good fit out to a radius of 20h−1cMpc for stacked filaments over a range of redshifts, lengths, and masses. The scale radii are approximately independent of redshift but increase as power laws with the comoving filament length. Lastly, we compare the scaling of the filament mass measured directly from the simulations to the predicted scaling from the halo–halo–matter three-point correlation function as a function of redshift and of the mass of the halo pairs. We find that both measured scalings are similar to, but somewhat shallower than the predictions, by 10 per cent and 30 per cent, respectively. These results provide a template to interpret present and upcoming observational results based on stacking, for example, weak lensing, thermal and kinetic Sunyaev-Zel’dovich, or X-ray observations.
The flickering radio jet from the quiescent black hole X-ray binary A0620-00
Authors: dePolo Donna L , Plotkin Richard M , Miller-Jones James C A , Strader Jay , Maccarone Thomas J , O’Doherty Tyrone N , Chomiuk Laura , Gallo Elena 
Published: September 2022

ABSTRACT
Weakly accreting black hole X-ray binaries launch compact radio jets that persist even in the quiescent spectral state, at X-ray luminosities ≲ 10−5 of the Eddington luminosity. However, radio continuum emission has been detected from only a few of these quiescent systems, and little is known about their radio variability. Jet variability can lead to misclassification of accreting compact objects in quiescence, and affects the detectability of black hole X-ray binaries in next-generation radio surveys. Here we present the results of a radio monitoring campaign of A0620 − 00, one of the best-studied and least-luminous known quiescent black hole X-ray binaries. We observed A0620 − 00 at 9.8 GHz using the Karl G Jansky Very Large Array on 31 epochs from 2017 to 2020, detecting the source $\sim 75{{\ \rm per\, cent}}$ of the time. We see significant variability over all time-scales sampled, and the observed flux densities follow a lognormal distribution with μ = 12.5 μJy and σ = 0.22 dex. In no epoch was A0620 − 00 as bright as in 2005 (51 ± 7 μJy), implying either that this original detection was obtained during an unusually bright flare, or that the system is fading in the radio over time. We present tentative evidence that the quiescent radio emission from A0620 − 00 is less variable than that of V404 Cyg, the only other black hole binary with comparable data. Given that V404 Cyg has a jet radio luminosity ∼20 times higher than A0620 − 00, this comparison could suggest that less luminous jets are less variable in quiescence.
NEOSSat observations of three transiting hot Jupiters
Authors: Fox Chris , Wiegert Paul 
Published: September 2022

Abstract
The Near Earth Object Surveillance Satellite (NEOSSat) is a Canadian-led 15 cm Earth-orbiting telescope originally designed to detect asteroids near the Sun. Its design is however also suitable for the observation of exoplanetary transits of bright stars. We used the NEOSSat platform to perform followup observations of several Transiting Exoplanets Survey Satellite (TESS) targets, both as a demonstration of NEOSSat capabilities for exoplanetary science and improve the orbital ephemerides and properties of these exoplanet systems. We are able to recover / confirm the orbital properties of such targets to within mutual error bars, demonstrating NEOSSat as a useful future contributor to exoplanetary science.
Generalized model-independent characterization of strong gravitational lenses VIII. Automated multiband feature detection to constrain local lens properties
Authors: Lin Joyce , Wagner Jenny , Griffiths Richard E 
Published: September 2022

ABSTRACT
As established in previous papers of this series, observables in highly distorted and magnified multiple images caused by the strong gravitational lensing effect can be used to constrain the distorting properties of the gravitational lens at the image positions. If the background source is extended and contains substructure, like star forming regions, which is resolved in multiple images, all substructure that can be matched across a minimum of three multiple images can be used to infer the local distorting properties of the lens. In this work, we replace the manual feature selection by an automated feature extraction based on SExtractor for Python and show its superior performance. Despite its aimed development to improve our lens reconstruction, it can be employed in any other approach, as well. Valuable insights on the definition of an ‘image position’ in the presence of noise are gained from our calibration tests. Applying it to observations of a five-image configuration in galaxy cluster CL0024 and the triple-image configuration containing Hamilton’s object, we determine local lens properties for multiple wavebands separately. Within current confidence bounds, all of them are consistent with each other, corroborating the wavelength-independence of strong lensing and offering a tool to detect deviations caused by micro-lensing and dust in further examples.
The orbital architecture and stability of the μ Arae planetary system
Authors: Goździewski K 
Published: September 2022

ABSTRACT
We re-analyse the global orbital architecture and dynamical stability of the HD 160691 planetary system. We have updated the best-fitting elements and minimal masses of the planets based on literature precision radial velocity (RV) measurements, now spanning 17.3 yr. This is twice the RVs interval used for the first characterization of the system in 2006. It consists of a Saturn- and two Jupiter-mass planets in low-eccentric orbits resembling the Earth–Mars–Jupiter configuration in the Solar system, as well as the close-in warm Neptune with a mass of ≃14 Earth masses. Here, we constrain this early solution with the outermost period to be accurate to one month. The best-fitting Newtonian model is characterized by moderate eccentricities of the most massive planets below 0.1 with small uncertainties ≃0.02. It is close but meaningfully separated from the 2e:1b mean motion resonance of the Saturn–Jupiter-like pair, but may be close to weak three-body MMRs. The system appears rigorously stable over a wide region of parameter space covering uncertainties of several σ. The system stability is robust to a five-fold increase in the minimal masses, consistent with a wide range of inclinations, from ≃20° to 90°. This means that all planetary masses are safely below the brown dwarf mass limit. We found a weak statistical indication of the likely system inclination $I \simeq \, 20^{\circ }$–30°. Given the well-constrained orbital solution, we also investigate the structure of hypothetical debris discs, which are analogues of the Main Belt and Kuiper Belt, and may naturally occur in this system.
Magnetically confined mountains on accreting neutron stars with multipole magnetic fields
Authors: Fujisawa Kotaro , Kisaka Shota , Kojima Yasufumi 
Published: September 2022

ABSTRACT
Magnetically confined mountains on accreting neutron stars are candidates for producing continuous gravitational waves. We formulate a magnetically confined mountain on a neutron star with strong multipole magnetic fields and obtain some sequences of numerical solutions. We find that the mass ellipticity of the mountain increases by one order of magnitude if the neutron star has strong multipole magnetic fields. As matter accretes on to the magnetic pole, the size of the mountain increases and the magnetic fields are buried. If the neutron star has a dipole magnetic field, the dipole magnetic field is buried and transformed into multipole components. By contrast, if the neutron star has both dipole and strong multipole magnetic fields, the multipole magnetic fields are buried and transformed into a negative dipole component. We also calculate magnetically confined mountains with toroidal magnetic fields and find that the ellipticity becomes slightly smaller when the mountain has toroidal magnetic fields. If the multipole magnetic fields are buried, they sustain the intense toroidal magnetic field near the stellar surface, and the ratio of the toroidal magnetic field to the poloidal magnetic field is close to 100. The hidden strong toroidal magnetic fields are sustained by the buried multipole magnetic fields.
Pre-explosion, explosion, and post-explosion jets in supernova SN 2019zrk
Authors: Soker Noam 
Published: September 2022

ABSTRACT
I analyse some properties of the luminous transient event SN 2019zrk and conclude that jets were the main powering sources of the pre-explosion outburst (pre-cursor) and ejection of a massive circumstellar matter (CSM), of the very energetic explosion itself, and of the post-explosion bump in the light curve. The pre-explosion energy source is mainly a companion (main sequence, Wolf–Rayet, neutron star, or black hole) star that accreted mass and launched jets. I find that the fast expansion of the CSM after acceleration by the explosion ejecta requires the explosion energy to be $\gtrsim 10^{52}\, {~\rm erg}$. Only jet-driven explosions can supply this energy in such SN 2009ip-like transients. I conclude that ejecta-CSM interaction is extremely unlikely to power the bright bump at about 110 d after explosion. Instead, I show by applying a jet-driven bump toy-model that post-explosion jets are the most likely explanation for the bump. I leave open the question of whether the explosion itself (main outburst) was a core collapse supernova (CCSN) or a common envelope jets supernova (CEJSN). In this study, I further connect peculiar transient events, here 2009ip-like transient events, to CCSNe by arguing that jets drive all events, from regular CCSNe through superluminous CCSNe and to many other peculiar and superenergetic transient events, including CEJSNe. Jet-powering cannot be ignored when analysing all these types of transients.
Measuring the Hubble constant with double gravitational wave sources in pulsar timing
Authors: McGrath Casey , D’Orazio Daniel J , Creighton Jolien 
Published: September 2022

ABSTRACT
Pulsar timing arrays (PTAs) are searching for gravitational waves from supermassive black hole binaries (SMBHBs). Here we show how future PTAs could use a detection of gravitational waves from individually resolved SMBHB sources to produce a purely gravitational wave-based measurement of the Hubble constant. This is achieved by measuring two separate distances to the same source from the gravitational wave signal in the timing residual: the luminosity distance DL through frequency evolution effects, and the parallax distance Dpar through wavefront curvature (Fresnel) effects. We present a generalized timing residual model including these effects in an expanding universe. Of these two distances, Dpar is challenging to measure due to the pulsar distance wrapping problem, a degeneracy in the Earth-pulsar distance and gravitational wave source parameters that requires highly precise, sub-parsec level, pulsar distance measurements to overcome. However, in this paper we demonstrate that combining the knowledge of two SMBHB sources in the timing residual largely removes the wrapping cycle degeneracy. Two sources simultaneously calibrate the PTA by identifying the distances to the pulsars, which is useful in its own right, and allow recovery of the source luminosity and parallax distances which results in a measurement of the Hubble constant. We find that, with optimistic PTAs in the era of the Square Kilometre Array, two fortuitous SMBHB sources within a few hundred Mpc could be used to measure the Hubble constant with a relative uncertainty on the order of 10 per cent.
Gaussian process model for the local stellar velocity field from Gaia data release 2
Authors: Nelson Patrick , Widrow Lawrence M 
Published: September 2022

ABSTRACT
We model the local stellar velocity field using position and velocity measurements for 4M stars from the second data release of Gaia. We determine the components of the mean or bulk velocity in $\sim 27\, 000$ spatially defined bins. Our assumption is that these quantities constitute a Gaussian process where the correlation between the bulk velocity at different locations is described by a simple covariance function or kernel. We use a sparse Gaussian process algorithm based on inducing points to construct a non-parametric, smooth, and differentiable model for the underlying mean stellar velocity field. We estimate the Oort constants A, B, C, and K and find values in excellent agreement with previous results. Maps of the velocity field within $2\, {\rm kpc}$ of the Sun reveal complicated substructures, which provide clear evidence that the local disc is in a state of disequilibrium. We present the first three-dimensional map of the divergence of the stellar velocity field and identify regions of the disc that may be undergoing compression and rarefaction.
Mid-infrared time-domain study of recent dust production events in the extreme debris disc of TYC 4209-1322-1
Authors: Moór Attila , Ábrahám Péter , Kóspál Ágnes , Su Kate Y L , Rieke George H , Vida Krisztián , Cataldi Gianni , Bódi Attila , Bognár Zsófia , Cseh Borbála , Csörnyei Géza , Egei Nóra , Farkas Anikó , Hanyecz Ottó , Ignácz Bernadett , Kalup Csilla , Könyves-Tóth Réka , Kriskovics Levente , Mészáros László , Pál András , Ordasi András , Sárneczky Krisztián , Seli Bálint , Sódor Ádám , Szakáts Róbert , Vinkó József , Zsidi Gabriella 
Published: September 2022

ABSTRACT
Extreme debris discs are characterized by unusually strong mid-infrared excess emission, which often proves to be variable. The warm dust in these discs is of transient nature and is likely related to a recent giant collision occurring close to the star in the terrestrial region. Here we present the results of a 877 d long, gap-free photometric monitoring performed by the Spitzer Space Telescope of the recently discovered extreme debris disc around TYC 4209-1322-1. By combining these observations with other time-domain optical and mid-infrared data, we explore the disc variability of the last four decades with particular emphasis on the last 12 yr. During the latter interval the disc showed substantial changes, the most significant was the brightening and subsequent fading between 2014 and 2018 as outlined in WISE data. The Spitzer light curves outline the fading phase and a subsequent new brightening of the disc after 2018, revealing an additional flux modulation with a period of ∼39 d on top of the long-term trend. We found that all these variations can be interpreted as the outcome of a giant collision that happened at an orbital radius of ∼0.3 au sometime in 2014. Our analysis implies that a collision on a similar scale could have taken place around 2010, too. The fact that the disc was already peculiarly dust rich 40 yr ago, as implied by IRAS data, suggests that these dust production events belong to a chain of large impacts triggered by an earlier even more catastrophic collision.