bluuebunny/crossref_metadata_2025_split huggingface dataset:
Merger-induced galaxy transformations in the artemis simulations
Authors: Dillamore Adam M , Belokurov Vasily , Font Andreea S , McCarthy Ian G 
Published: April 2022

ABSTRACT
Using the artemis set of 45 high-resolution cosmological simulations, we investigate a range of merger-induced dynamical transformations of Milky Way-like galaxies. We first identify populations of accreted stars on highly radial orbits, similar to the ‘Gaia Sausage’ in the Milky Way. We show that ≈1/3 of the artemis galaxies contain a similar feature, and confirm that they usually comprise stellar debris from the most massive accreted satellite. Selecting 15 galaxies with discs at the present-day, we study their changes around the times of the GS-like mergers. Dark matter haloes of many of these exhibit global changes in shape and orientation, with almost half becoming significantly more spherical when the mergers occur. Focusing on the galaxies themselves, we find that 4/15 have stellar discs which experience large changes in the orientation of their angular momentum (AM) axes, at rates of up to ∼60 degrees Gyr−1. By calculating the orbital angular momentum axes of the satellites before they are accreted, we show that there is a tendency for the disc’s AM to become more aligned with this axis after the merger. We also investigate the origin of in situ retrograde stars, analogous to the ‘Splash’ in the Milky Way. Tracing them back to earlier snapshots, we demonstrate that they were often disrupted on to their extreme orbits by multiple early mergers. We also find that the total mass of these stars outside the central regions positively correlates with the total accreted stellar mass.
On the lower limit of contact binary star periods
Authors: Koen Chris 
Published: April 2022

ABSTRACT
Data for 405 contact binary systems extracted from a recent compilation are supplemented by information from the literature for an additional ten ultrashort period (P &lt; 0.2 d) binaries. This is used to calibrate period–luminosity–temperature relations for contact binaries. The derived relations are applied to a standard mean temperature–luminosity tabulation to obtain predicted periods for contact systems over the spectral range M9.5–A2. Minimum periods in the range 0.08–0.15 d follow, depending on the precise period–luminosity–temperature model fitted.
Characterizing eclipsing white dwarf M dwarf binaries from multiband eclipse photometry
Authors: Brown Alex J , Parsons Steven G , Littlefair Stuart P , Wild James F , Ashley R P , Breedt E , Dhillon V S , Dyer M J , Green M J , Kerry P , Marsh T R , Pelisoli I , Sahman D I 
Published: April 2022

ABSTRACT
With the prevalence of wide-field, time-domain photometric sky surveys, the number of eclipsing white dwarf (WD) systems being discovered is increasing dramatically. An efficient method to follow these up will be key to determining any population trends and finding any particularly interesting examples. We demonstrate that multiband eclipse photometry of binaries containing a WD and an M dwarf can be used to determine the masses and temperatures of the WDs to better than 5 per cent. For the M dwarfs, we measure their parameters to a precision of better than 6 per cent with the uncertainty dominated by the intrinsic scatter of the M dwarf mass–radius relationship. This precision is better than what can typically be achieved with low-resolution spectroscopy. The nature of this method means that it will be applicable to LSST data in the future, enabling direct characterization without follow-up spectroscopy. Additionally, we characterize three new post-common-envelope binaries from their eclipse photometry, finding two systems containing hot helium-core WDs with low-mass companions (one near the brown dwarf transition regime) and a possible detached cataclysmic variable at the lower edge of the period gap.
Bending waves in velocity space: a first look at the THINGS sample
Authors: Nandakumar Meera , Narayan Chaitra , Dutta Prasun 
Published: April 2022

ABSTRACT
Detection of bending waves is a highly challenging task even in nearby disc galaxies due to their sub-kpc bending amplitudes. However, simulations show that the harmonic bending of a Milky Way-like disc galaxy is associated with a harmonic fluctuation in the measured line-of-sight (los) velocities as well, and can be regarded as a kinematic signature of a manifested bending wave. Here, we look for similar kinematic signatures of bending waves in H i discs, as they extend too much beyond the optical radii. We present a multipole analysis of the H i los residual velocity fields of six nearby spiral galaxies from the THINGS sample, which uncovers the bending wave-induced velocity peaks. This allows us to identify the radial positions and amplitudes of the different bending modes present in the galaxies. We find that all of our sample discs show a combined kinematic signature of superposition of a few lower order bending modes, suggesting that bending waves are a common phenomenon. The identified velocity peaks are found to be of modes m = 2, 3, and 4, not more than 15 km s−1 in amplitude and spread across the entire H i disc. Interestingly, they appear to be concentrated near the optical edge of their host galaxies. Also, m = 2 appears to be more common than the other two modes.
The effect of aspect changes on Near-Earth Asteroid phase curves
Authors: Jackson S L , Rozitis B , Dover L R , Green S F , Kolb U C , Andrews A E , Lowry S C 
Published: April 2022

ABSTRACTPhase curves of asteroids are typically considered to depend solely on the scattering properties of airless particulate surfaces and the size of the object being studied. In this study, we demonstrate the additional dependence of phase curves on object shape, rotation pole orientation, and viewing geometry over an apparition. Variations in the phase curve of near-Earth asteroid (159402) 1999 AP10 over its apparition from 2020 July to 2021 January are verified to be due to aspect changes over the apparition. This is achieved through shape modelling of the asteroid and simulation of the phase curve over the apparition. We present simulations of asteroid phase curves over a range of geometries to understand the potential magnitude of this aspect effect, and under which circumstances it can begin to dominate in the phase curves. This dependence on aspect may introduce significant additional uncertainty in the properties derived from phase-curve data. We provide and demonstrate software code to estimate the aspect-related uncertainty in near-Earth asteroid phase curves through simulation and model fitting of a randomly generated sample of ellipsoidal asteroid models over the observed viewing geometry. We demonstrate how ignoring this effect may lead to misleading interpretations of the data and underestimation of uncertainties in further studies, such as those in the infrared that use phase curve derived parameters when fitting physical properties of an asteroid.
sipgi: an interactive pipeline for spectroscopic data reduction
Authors: Gargiulo A , Fumana M , Bisogni S , Franzetti P , Cassarà L P , Garilli B , Scodeggio M , Vietri G 
Published: April 2022

ABSTRACT
We present sipgi, a spectroscopic pipeline to reduce optical/near-infrared data from slit-based spectrographs. sipgi is a complete spectroscopic data reduction environment, which retains the high level of flexibility and accuracy typical of the standard ‘by-hand’ reduction methods but is characterized by a significantly higher level of efficiency. This is obtained by exploiting three main concepts: (i) the instrument model: at the core of the data reduction is an analytic description of the main calibration relations (e.g. spectra location and wavelength calibration) that can be easily checked and adjusted on data using a graphical tool; (ii) a built-in data organizer that classifies the data, together with a graphical interface that helps in providing the recipes with the correct input; (iii) the design and flexibility of the reduction recipes: The number of tasks required to perform a complete reduction is minimized, while preserving the possibility of verifying the accuracy of the main stages of data-reduction process with provided tools. The current version of sipgi manages data from the MODS and LUCI spectrographs mounted at the Large Binocular Telescope, and it is our plan to extend sipgi to support other through-slit spectrographs. Meanwhile, to allow using the same approach based on the instrument model with other instruments, we have developed SpectraPy, a spectrograph-independent python library working on through-slit spectra. In its current version, SpectraPy produces two-dimensional wavelength-calibrated spectra corrected by instrument distortions. The current release of sipgi and its documentation can be downloaded fromhttp://pandora.lambrate.inaf.it/sipgi/, while SpectraPy can be found at http://pandora.lambrate.inaf.it/SpectraPy/.
On the detectability of massive black hole merger events by Laser Interferometry Space Antenna
Authors: Banks Samuel , Lee Katharine , Azimi Nazanin , Scarborough Kendall , Stefanov Nikolai , Periwal Indra , Chen Nianyi , DeGraf Colin , Di Matteo Tiziana 
Published: April 2022

ABSTRACTThe launch of space-based gravitational-wave (GW) detectors (e.g. Laser Interferometry Space Antenna; LISA) and current and upcoming Pulsar Timing Arrays will extend the GW window to low frequencies, opening new investigations into dynamical processes involving massive black hole binaries (MBHBs) and their mergers across cosmic time. MBHBs are expected to be among the primary sources for the upcoming low-frequency (10−4–10−1 Hz) window probed by LISA. It is important to investigate the expected supermassive BH merger rates and associated signals, to determine how potential LISA events are affected by physics included in current models. To study this, we post-process the large population of MBHBs in the Illustris simulation to account for dynamical friction time delays associated with BH infall/inspiral. We show that merger delays associated with binary evolution have the potential to decrease the expected merger rates, with $M_{\rm {BH}}\ \gt\ 10^6\ \mathrm{M}_\odot$ MBHBs (the lowest mass in Illustris) decreasing from ∼3 to ∼0.1 yr−1, and shifting the merger peak from z ∼2 to ∼1.25. During this time, we estimate that accretion grows the total merging mass by as much as 7x the original mass. Importantly, however, dynamical friction-associated delays (which shift the mergers toward lower redshift and higher masses) lead to a stronger signal/strain for the emitted GWs in the LISA band, increasing mean frequency from 10−3.1 to 10−3.4–10−4.0 Hz, and mean strain from 10−17.2 to 10−16.3–10−15.3. Finally, we show that after including a merger delay and associated MBH growth, mergers still tend to lie on the typical MBH–M* relation, but with an increased likelihood of an undermassive BH.
Galaxy and mass assembly (GAMA): Self-Organizing Map application on nearby galaxies
Authors: Holwerda Benne W , Smith Dominic , Porter Lori , Henry Chris , Porter-Temple Ren , Cook Kyle , Pimbblet Kevin A , Hopkins Andrew M , Bilicki Maciej , Turner Sebastian , Acquaviva Viviana , Wang Lingyu , Wright Angus H , Kelvin Lee S , Grootes Meiert W 
Published: April 2022

ABSTRACTGalaxy populations show bimodality in a variety of properties: stellar mass, colour, specific star-formation rate, size, and Sérsic index. These parameters are our feature space. We use an existing sample of 7556 galaxies from the Galaxy and Mass Assembly (GAMA) survey, represented using five features and the K-means clustering technique, showed that the bimodalities are the manifestation of a more complex population structure, represented by between two and six clusters. Here we use Self-Organizing Maps (SOM), an unsupervised learning technique that can be used to visualize similarity in a higher dimensional space using a 2D representation, to map these 5D clusters in the feature space on to 2D projections. To further analyse these clusters, using the SOM information, we agree with previous results that the sub-populations found in the feature space can be reasonably mapped on to three or five clusters. We explore where the ‘green valley’ galaxies are mapped on to the SOM, indicating multiple interstitial populations within the green valley population. Finally, we use the projection of the SOM to verify whether morphological information provided by GalaxyZoo users, for example, if features are visible, can be mapped on to the SOM-generated map. Voting on whether galaxies are smooth, likely ellipticals, or ‘featured’ can reasonably be separated but smaller morphological features (bar, spiral arms) can not. SOMs promise to be a useful tool to map and identify instructive sub-populations in multidimensional galaxy survey feature space, provided they are large enough.
Linking the properties of accreting white dwarfs with the ionization state of their ambient medium
Authors: Souropanis D , Chiotellis A , Boumis P , Chatzikos M , Akras S , Piersanti L , Ruiter A J , Ferland G J 
Published: April 2022

ABSTRACT
Steadily accreting white dwarfs (WDs) are efficient sources of ionization and thus are able to create extended ionized nebulae in their vicinity. These nebulae represent ideal tools for the detection of accreting WDs, given that in most cases the source itself is faint. In this work, we combine radiation transfer simulations with known H- and He-accreting WD models, providing for the first time the ionization state and the emission-line spectra of the formed nebulae as a function of the WD mass, the accretion rate and the chemical composition of the accreted material. We find that the nebular optical line fluxes and radial extent vary strongly with the WD’s accretion properties, peaking in systems with WD masses of 0.8–1.2 $\rm M_{\odot }$. Projecting our results on so-called BPT diagnostic diagrams, we show that accreting WD nebulae possess characteristics distinct from those of H ii-like regions, while they have line ratios similar to those in galactic low-ionization emission-line regions. Finally, we compare our results with the relevant constraints imposed by the lack of ionized nebulae in the vicinity of supersoft X-ray sources (SSSs) and Type Ia supernova remnants – sources that are related to steadily accreting WDs. The large discrepancies uncovered by our comparison rule out any steadily accreting WD as a potential progenitor of the studied remnants and additionally require the ambient medium around the SSSs to be less dense than 0.2 $\rm cm^{-3}$. We discuss possible alternatives that could bridge the incompatibility between the theoretical expectations and relevant observations.
Hydrogen emission from meteors and meteorites: mapping traces of H2O molecules and organic compounds in small Solar system bodies
Authors: Matlovič Pavol , Pisarčíková Adriana , Tóth Juraj , Mach Pavel , Čermák Peter , Loehle Stefan , Kornoš Leonard , Ferrière Ludovic , Šilha Jiří , Leiser David , Ravichandran Ranjith 
Published: April 2022

ABSTRACT
The hydrogen emission from meteors is assumed to originate mainly from the meteoroid composition, making it a potential tracer of H2O molecules and organic compounds. H α line was previously detected in individual fireballs, but its variation in a larger meteor data set and dependence on the dynamical origin and physical properties have not yet been studied. Here, we investigate the relative intensity of H α within 304 meteor spectra observed by the AMOS (All-sky Meteor Orbit System) network. We demonstrate that H α emission is favoured in faster meteors (vi &gt; &gt; 30 km s−1) which form the high-temperature spectral component. H α was found to be a characteristic spectral feature of cometary meteoroids with ∼92 per cent of all meteoroids with detected H α originating from Halley-type and long-period orbits. Our results suggest that hydrogen is being depleted from meteoroids with lower perihelion distances (q &lt; 0.4 au). No asteroidal meteoroids with detected H emission were found. However, using spectral data from simulated ablation of different meteorite types, we show that H emission from asteroidal materials can occur, and apparently correlates with their water and organic matter content. Strongest H emission was detected from carbonaceous chondrites (CM and CV) and achondrites (ureilite and aubrite), while it was lacking in most ordinary chondrites. The detection of H α in asteroidal meteoroids could be used to identify meteoroids of carbonaceous or achondritic composition. Overall, our results suggest that H α emission correlates with the emission of other volatiles (Na and CN) and presents a suitable tracer of water and organic matter in meteoroids.
Chaos over order: mapping 3D rotation of triaxial asteroids and minor planets
Authors: Makarov Valeri V , Goldin Alexey , Tkachenko Alexei V , Veras Dimitri , Noyelles Benoît 
Published: April 2022

ABSTRACT
Celestial bodies approximated with rigid triaxial ellipsoids in a two-body system can rotate chaotically due to the time-varying gravitational torque from the central mass. At small orbital eccentricity values, rotation is short-term orderly and predictable within the commensurate spin–orbit resonances, while at eccentricity approaching unity, chaos completely takes over. Here, we present the full three-dimensional rotational equations of motion around all three principal axes for triaxial minor planets and two independent methods of numerical solution based on Euler rotations and quaternion algebra. The domains of chaotic rotation are numerically investigated over the entire range of eccentricity with a combination of trial integrations of Euler’s equations of motion and the GALI(k) (Generalized Alignment Index) method. We quantify the dependence of the order–chaos boundaries on shape by changing a prolateness parameter, and find that the main 1:1 spin–orbit resonance disappears for specific moderately prolate shapes already at eccentricities as low as 0.3. The island of short-term stability around the main 1:1 resonance shrinks with increasing eccentricity at a fixed low degree of prolateness and completely vanishes at approximately 0.8. This island is also encroached by chaos on longer time-scales, indicating longer Lyapunov exponents. Trajectories in the close vicinity of the 3:2 spin–orbit resonance become chaotic at smaller eccentricities, but separated enclaves of orderly rotation emerge at eccentricities as high as 0.8. Initial perturbations of rotational velocity in latitude away from the exact equilibrium result in a spectrum of free libration, nutation, and polar wander, which is not well matched by the linearized analysis omitting the inertial terms.
Aquinas’s Theory of Goodness
Authors: Stump Eleonore 
Published: April 2022

Abstract
The aim of this essay is to sketch the basic outline of Aquinas’s metaethics and its support for his virtue-based ethics. When Aquinas’s central metaethical thesis is combined with his theological views, especially his understanding of the doctrine of divine simplicity, then the theological interpretation of the central metaethical thesis constitutes the basis for a religious ethics that makes God essential to human morality but without tying morality to God’s will. The result is a metaphysically grounded, objective normative virtue ethics which is theological at least in this sense that it is ultimately based in God’s nature.
Anti-Climacus and the Demoralization of Sin
Authors: Hüsch Sebastian , Viertbauer Klaus 
Published: April 2022

AbstractThe paper develops the claim that in The Sickness unto Death (1849), Kierkegaard conceptualizes a demoralized understanding of sin. Rather than interpreting sin as moral guilt, he proposes a concept of sin that takes the form of alienation. The claim is unfolded in a three-step argumentation: First, we identify crucial hermeneutical issues and stress the role of the pseudonyms within Kierkegaard’s writings. Second, we offer a detailed analysis of the theory of self-consciousness developed by Anti-Climacus. Finally, using the romantic interpretation of Kierkegaard as a foundation, we demonstrate how Anti-Climacus conceptualizes sin as alienation
The Tribute of Faith: Theistic Commitment as Moral Gesture
Authors: Schellenberg J L 
Published: April 2022

Abstract
In this paper I explore and defend the idea that those who struggle intellectually in theistic religious practice can be given a good reason to persist in it by treating their continuing practice as a way of paying tribute to people and projects and personal relationships and indeed to the whole moral dimension of human life, expressing how important and profoundly significant these things are to them. This ‘tribute of faith’ is a gesture that one makes with one’s life—a moral gesture. The key thought is that the sayings and other doings of a religious life allow one to treat the world as one in which the things, such as projects and people, that are, for one, most deeply imbued with moral value will achieve fulfilment—a fulfillment that without the truth of religious claims they would often be denied.
Shaping the genome via lengthwise compaction, phase separation, and lamina adhesion
Authors: Brahmachari Sumitabha , Contessoto Vinícius G , Di Pierro Michele , Onuchic José N 
Published: April 2022

Abstract
The link between genomic structure and biological function is yet to be consolidated, it is, however, clear that physical manipulation of the genome, driven by the activity of a variety of proteins, is a crucial step. To understand the consequences of the physical forces underlying genome organization, we build a coarse-grained polymer model of the genome, featuring three fundamentally distinct classes of interactions: lengthwise compaction, i.e., compaction of chromosomes along its contour, self-adhesion among epigenetically similar genomic segments, and adhesion of chromosome segments to the nuclear envelope or lamina. We postulate that these three types of interactions sufficiently represent the concerted action of the different proteins organizing the genome architecture and show that an interplay among these interactions can recapitulate the architectural variants observed across the tree of life. The model elucidates how an interplay of forces arising from the three classes of genomic interactions can drive drastic, yet predictable, changes in the global genome architecture, and makes testable predictions. We posit that precise control over these interactions in vivo is key to the regulation of genome architecture.