Miracle-dz/UniFAR-FTUs huggingface dataset:
2008 LC18: A potentially unstable Neptune Trojan

The recent discovery of the first Neptune Trojan at the planet's trailing (L5) Lagrange point, 2008 LC18, offers an opportunity to confirm the formation mechanism of a member of this important tracer population for the Solar system's dynamical history. We tested the stability of 2008 LC18's orbit through a detailed dynamical study, using test particles spread across the ±3σ range of orbital uncertainties in a,e,i and Ω. This showed that the wide uncertainties of the published orbit span regions of both extreme dynamical instability, with lifetimes 1Gyr. The stability of 2008 LC18's clones is greatly dependent on their semimajor axis and only weakly correlated with their orbital eccentricity. Test particles on orbits with an initial semimajor axis of less than 29.91au have dynamical half-lives shorter than 100Myr; in contrast, particles with an initial semimajor axis of greater than 29.91au exhibit such strong dynamical stability that almost all are retained over the 1Gyr of our simulations. More observations of this object are necessary to improve the orbit. If 2008 LC18 is in the unstable region, then our simulations imply that it is either a temporary Trojan capture or a representative of a slowly decaying Trojan population (like its sibling the L4 Neptunian Trojan 2001 QR322), and that it may not be primordial. Alternatively, if the orbit falls into the larger, stable region, then 2008 LC18 is a primordial member of the highly stable and highly inclined component of the Neptune Trojan population, joining 2005 TN53 and 2007 VL305. We attempted to recover 2008 LC18 using the 2.3-m telescope at Siding Spring Observatory to provide this astrometry, but were unsuccessful due to the high stellar density of its current sky location near the Galactic centre. The recovery of this object will require a telescope in the 8-m class.
OPTICAL VARIABILITY OF AGNs IN THE PTF/iPTF SURVEY

We characterize the optical variability of quasars in the Palomar Transient Factory and intermediate Palomar Transient Factory (PTF/iPTF) surveys. We re-calibrate the r-band light curves for ∼28,000 luminous, broad-line active galactic nuclei from the SDSS, producing a total of ∼2.4 million photometric data points. We utilize both the structure function (SF) and power spectrum density (PSD) formalisms to search for links between the optical variability and the physical parameters of the accreting supermassive black holes that power the quasars. The excess variance (SF2) of the quasar sample tends to zero at very short time separations, validating our re-calibration of the time-series data. We find that the the amplitude of variability at a given time-interval, or equivalently the timescale of variability to reach a certain amplitude, is most strongly correlated with luminosity with weak or no dependence on black hole mass and redshift. For a variability level of SF(τ) = 0.07 mag, the timescale has a dependency of . This is broadly consistent with the expectation from a simple Keplerian accretion disk model, which provides . The PSD analysis also reveals that many quasar light curves are steeper than a damped random walk. We find a correlation between the steepness of the PSD slopes, specifically the fraction of slopes steeper than 2.5, and black hole mass, although we cannot exclude the possibility that luminosity or Eddington ratio are the drivers of this effect. This effect is also seen in the SF analysis of the (i)PTF data, and in a PSD analysis of quasars in the SDSS Stripe 82.
Chemical evolution of the Galactic bulge: different stellar populations and possible gradients

Context. The recent although controversial discovery of two main stellar populations in the Galactic bulge, one metal-poor with a spheroid kinematics and the other metal-rich with a bar-like kinematics, suggests a revision of the classical model for bulge formation. Aims. We aim at computing in detail the chemical evolution of the Galactic bulge in order to explain the existence of the two main stellar populations. We also plan to explore the possible existence of spatial abundance gradients inside the bulge. Methods. To do that, we adopt a chemical evolution model that follows the evolution of several chemical species (from H to Ba) and takes into account both infall and outflow of gas. We assume that the metal-poor population formed first and on a short timescale, in agreement with previous models, while the metal-rich population formed later and out of the enriched gas either left from the formation of the previous one or originating from the inner disk. We predict the stellar distribution functions for Fe and Mg, the mean � [Fe/H]� and � [Mg/H]� as well as the [Mg/Fe] vs. [Fe/H] relations in the two stellar populations. Then, we consider the case in which the metal-poor population could be the result of sub-populations formed with different chemical enrichment rates. In particular, the population close to the Galactic center could have evolved very fast, while the more external population could have evolved more slowly, in agreement with the dissipational gravitational collapse scenario. Results. When compared with observations, our results confirm that the old more metal-poor stellar population formed very fast (on a timescale of 0.1–0.3 Gyr) by means of an intense burst of star formation coupled with an initial mass function flatter than in the solar vicinity, but not as flat as suggested in previous works. The metal-rich population, instead, should have formed on a longer timescale (∼3 Gyr). We predict differences in the mean abundances of the two populations: in particular, we find a difference of ∼–0.52 dex for � [Fe/H]� . These differences can be interpreted as a metallicity gradient. We also predict possible gradients for Fe, O, Mg, Si, S, and Ba between sub-populations inside the metal-poor population itself (e.g., –0.145 dex for � [Fe/H]� ). Finally, by means of a chemodynamical model following a dissipational collapse, we predict a gradient inside 500 pc from the Galactic center of −0.26 dex kpc −1 in Fe. Conclusions. We conclude that the chemical evolution of the Galactic bulge, as suggested by its stellar populations, has been quite complex. A stellar population forming by means of a classical gravitational gas collapse is probably mixed with a younger stellar population created perhaps by the bar evolution. The differences among their mean abundances can be interpreted as a gradient. On the basis of both chemical and chemo-dynamical models, we also conclude that it is possible that the metal-poor population itself contains abundance gradients and thus different stellar populations.
Autoregressive Planet Search: Methodology

The detection of periodic signals from transiting exoplanets is often impeded by extraneous aperiodic photometric variability, either intrinsic to the star or arising from the measurement process. Frequently, these variations are autocorrelated wherein later flux values are correlated with previous ones. In this work, we present the methodology of the autoregessive planet search (ARPS) project, which uses the autoregressive integrated moving average (ARIMA) and related statistical models that treat a wide variety of stochastic processes, as well as nonstationarity, to improve detection of new planetary transits. Provided a time series is evenly spaced or can be placed on an evenly spaced grid with missing values, these low-dimensional parametric models can prove very effective. We introduce a planet search algorithm to detect periodic transits in the residuals after the application of ARIMA models. Our matched-filter algorithm, the transit comb filter (TCF), is closely related to the traditional box-fitting least-squares and provides an analogous periodogram. Finally, if a previously identified or simulated sample of planets is available, selected scalar features from different stages of the analysis—the original light curves, ARIMA fits, TCF periodograms, and folded light curves—can be collectively used with a multivariate classifier to identify promising candidates while efficiently rejecting false alarms. We use Random Forests for this task, in conjunction with receiver operating characteristic curves, to define discovery criteria for new, high-fidelity planetary candidates. The ARPS methodology can be applied to both evenly spaced satellite light curves and densely cadenced ground-based photometric surveys.
A TENTATIVE DETECTION OF AN EMISSION LINE AT 1.6 μm FOR THE z ∼ 12 CANDIDATE UDFj-39546284

We present deep WFC3 grism observations of the candidate z ∼ 12 galaxy UDFj-39546284 in the Hubble Space Telescope (HST) Ultra Deep Field (UDF), by combining spectroscopic data from the 3D-HST and CANDELS surveys. The total exposure time is 40.5 ks and the spectrum covers 1.10 < λ < 1.65 μm. We search for faint emission lines by cross-correlating the two-dimensional G141 spectrum with the observed H160 morphology, a technique that is unique to slitless spectroscopy at HST resolution. We find a 2. 7σ detection of an emission line at 1.599 μm—just redward of the JH140 filter—with flux 3.5 ± 1.3 × 10−18 erg s−1 cm−2. Assuming that the line is real, it contributes 110% ± 40% of the observed H160 flux and has an observed equivalent width >7300 Å. If the line is confirmed, it could be Lyα at z = 12.12. However, a more plausible interpretation, given current results, could be a lower redshift feature such as [O iii]λ4959,5007 at z = 2.19. We find two other 3D-HST [O iii] emitters within 1000 km s−1 of that redshift in the GOODS-South field. Additional support for this interpretation comes from the discovery of a bright “[O iii] blob” with a secure G141 grism redshift of z = 1.605. This object has a strikingly large observed equivalent width of nearly 9000 Å that results in similar “dropout” colors as UDFj-39546284.
Rotation Curve Decompositions with Gaussian Processes: Taking into Account Data Correlations Leads to Unbiased Results

Correlations between velocity measurements in disk galaxy rotation curves are usually neglected when fitting dynamical models. Here I show how data correlations can be taken into account in rotation curve decompositions using Gaussian Processes. I find that marginalizing over correlation parameters proves critical to obtain unbiased estimates of the luminous and dark matter distributions in galaxies.
Impact of the wave/wind induced oscillations on the power performance of the WindFloat wind turbine

The main objective of this work is the characterization of the wave/wind induced oscillations on the power performance of the wind turbine operating on a WindFloat floating system. To assess the potential impact on the wind turbine power performance induced by these oscillations, the nacelle movements of the WindFloat wind turbine were monitored using accelerometer sensors synchronized with : 1) metocean data measured with a buoy; 2) wind turbine power data installed in the WindFloat floating system; and 3) wind speed data gathered from a nacelle-mounted LiDAR. Based on this data, a clustering analysis approach is proposed. No meaningful relationship between the ocean parameters and the nacelle movements or the wind power production could be established. The obtained results suggest that the dynamic adaptation of the drive train (mainly due to wind turbine torque control) to a fast oscillating (primary energy) moving force is the source of the largest oscillations in the nacelle of the WindFloat wind turbine. Nevertheless, results suggest that the wind/wave induced oscillations and their impact on the power performance of the WindFloat wind turbine is low considering its nominal capacity. Outcomes of this work were extremely relevant to demonstrate the stability of the WindFloat system, and, consequently, also important for the development of the floating wind offshore industry (and other technologies).
The stability of spectroscopic instruments: a unified Allan variance computation scheme

Context. The Allan variance is a standard technique to characterise the stability of spectroscopic instruments used in astronomical observations. The period for switching between source and reference measurement is often derived from the Allan minimum time. However, various methods are applied to compute the Allan variance spectrum and to use its characteristics in the setup of astronomical observations. Aims. We propose a new approach for the computation of the Allan variance of spectrometer data combining the advantages of the two existing methods into a unified scheme. Using the Allan variance spectrum we derive the optimum strategy for symmetric observing schemes minimising the total uncertainty of the data resulting from radiometric and drift noise. Methods. The unified Allan variance computation scheme is designed to trace total-power and spectroscopic fluctuations within the same framework. The method includes an explicit error estimate both for the individual Allan variance spectra and for the derived stability time. A new definition of the instrument stability time allows to characterise the instrument even in the case of a fluctuation spectrum shallower than 1/f, as measured for the total power fluctuations in high-electron-mobility transistors. Results. A first analysis of test measurements for the HIFI instrument shows that gain fluctuations represent the main cause of instrumental instabilities leading to large differences between the stability times relevant for measurements aiming at an accurate determination of the continuum level and for purely spectroscopic measurements. Fast switching loops are needed for a reliable determination of the continuum level, while most spectroscopic measurements can be set up in such a way that baseline residuals due to spectroscopic drifts are at a lower level than the radiometric noise. We find a non-linear impact of the binning of spectrometer channels on the resulting noise and the Allan time deviating from the description in existing theoretical treatments.
Mapping the electrophysiological structure of dystonic Globus Pallidus pars interna through intraoperative microelectrode recordings

Objective. The Globus Pallidus pars interna (GPi) is one of the main targets for Deep Brain Stimulation (DBS) therapies for dystonia and other movement disorders. Still, a complete picture of the spiking dynamics of the nucleus is far from being achieved. Microelectrode recordings (MER) provide a unique brain window opportunity to shed light on GPi organization, which might support intraoperative DBS target localization, as previously done for the Subthalamic nucleus (STN). Approach. Here we propose a novel procedure to analyze explorative MERs from DBS implants in dystonic patients. The procedure identifies the neural activity markers discriminating neurons in the GPi from those in the neighbouring structures, as well as the markers discriminating neurons located in different regions within the GPi. Main results. The identification of the borders of the GPi based on neural markers was a difficult task, due to internal inhomogeneities in GPi firing dynamics. However, the procedure was able to exploit these inhomogeneities to characterize the internal electrophysiological structure of the GPi. In particular, we found a reliable dorsolateral gradient in firing activity and regularity. Significance. Overall, we characterized the spatial distribution of neural activity markers in the dystonic GPi, paving the way for the use of these markers for DBS target localization. The procedure we developed to achieve this result could be easily extended to MER performed for other disorders and in other areas.
Genomic Characterization of Dengue Virus Outbreak in 2022 from Pakistan

Pakistan, a dengue endemic country has encountered several outbreaks during the past decade. The current study aimed to explore the serotype and genomic diversity of dengue virus responsible for the 2022 outbreak in Pakistan. During August-October 2022, blood samples (n=436) were collected from dengue patients, among which 64.4% (n=281) were positive based on RT-PCR. A subset of DENV-2 and DENV-1 samples were further subjected to whole-genome sequencing. In terms of gender and age, dengue infection was more prevalent in male patients (62.9%) with more adults (77.5%) being infected. Moreover, serotyping revealed DENV-2 to be most predominant serotype (64%; n=180), followed by DENV-1 (35.2%; n=99) and DENV-3 (0.35%; n=1). Phylogenetic analysis of sequenced samples indicates that all the samples (n=8) belong to the DENV-2 Cosmopolitan genotype, falling within a single monophyletic clade that is closely related to sequences from China and Singapore in 2018. Dengue virus dynamics reported in the current study warrants large scale genomic surveillance in order to better respond to future outbreaks.
The Influence of Accretion Disk Thickness on the Large-scale Magnetic Dynamo

The evolution of the magnetic field from the large-scale dynamo is considered a central feature of the accretion disk around a black hole. The resulting low-frequency oscillations introduced from the growth and decay of the field strength, along with the change in field orientation, play an integral role in the accretion disk behavior. Despite the importance of this process and how commonly it is invoked to explain variable features, it still remains poorly understood. We present a study of the dynamo using a suite of four global, high-resolution, MHD accretion disk simulations. We systematically vary the scale height ratio and find the large-scale dynamo fails to organize above a scale height ratio of h/r ≳ 0.2. Using spacetime diagrams of the azimuthal magnetic field, we show the large-scale dynamo is well ordered in the thinner accretion disk models, but fails to develop the characteristic “butterfly” pattern when the scale height ratio is increased, a feature which is also reflected in the power spectra. Additionally, we calculate the dynamo α-parameter and generate synthetic light curves. Using an emission proxy, we find the disks have markedly different characters as stochastic photometric fluctuations have a larger amplitude when the dynamo is unordered.
Synthetic line and continuum linear-polarization signatures of axisymmetric Type II supernova ejecta

We present synthetic single-line and continuum linear-polarization signatures due to electron scattering in axially symmetric Type II supernovae (SNe) which we calculate using a Monte Carlo and a long characteristic radiative-transfer code. Aspherical ejecta are produced by prescribing a latitudinal scaling or stretching of SN ejecta inputs obtained from recent 1D non-local thermodynamic equilibrium (non-LTE) time-dependent calculations. We study polarization signatures as a function of inclination, shape factor, wavelength, line identity and post-explosion time. At early times, cancellation and optical-depth effects make the polarization intrinsically low, even causing complicated sign reversals with inclination or continuum wavelength, and across line profiles. While the line polarization is positive (negative) for an oblate (prolate) morphology at the peak and in the red wing, the continuum polarization may be of any sign. These complex polarization variations are produced not just by the asymmetric distribution of scatterers but also of the flux. Our early-time signatures are in contradiction with predictions for a centrally illuminated aspherical nebula, although this becomes a better approximation at nebular times. For a fixed asymmetry, our synthetic continuum polarization is generally low, may evolve non-monotonically during the plateau phase, but it systematically rises as the ejecta become optically thin and turn nebular. Thus changes in polarization over time do not necessarily imply a change in the asymmetry of the ejecta. The SN structure (e.g. density and ionization) critically influences the level of polarization. Importantly, a low polarization (<0.5 per cent) at early times does not necessarily imply a low degree of asymmetry as usually assumed. Asphericity influences line-profile morphology and the luminosity, and thus may compromise the accuracy of SN characteristics inferred from these.
Modeling of Atmospheric Flow Around a Coastal Cape: Lee Side Story

The current research focuses on mesoscale dynamics of the atmospheric circulation around an idealized coastal cape representing typical summertime circulation along the northwest coast of the U.S., studied using a mesoscale coupled ocean-atmosphere modeling system. The orographic wind maximum features a strong NW flow extending a few hundred kilometers downstream and seaward of the cape, which closely follows mesoscale orographic low pressure developed in the lee of the cape. Both wind maximum and the lee trough experience a pronounced diurnal cycle, marked by maximum northwest flow and minimum pressure in the local evening hours (its opposite phase during morning hours), and confirmed by observations from limited buoy and coastal stations. Vertical structure of the atmospheric boundary layer over the coastal ocean on the lee side of the cape indicated the downward propagation of potential temperature and wind features during the course of the day, as opposed to the traditional surface-driven development of the atmospheric boundary layer. Momentum analysis showed the local pressure gradients near the surface vary greatly depending on the relative location about the cape. Strong perturbations in relative vorticity downwind of the cape supported the hypothesis that mountain dynamics have a key role in establishing wind regime around the cape. The sensitivity studies indicated the importance of coastal terrain elevation on the formation and the strength of the lee trough and wind maximum. Higher coastal topography was found to cause greater separation of the upwelling front (jet) from the coast downwind of the cape.
High-sensitivity plasmonic refractive index sensing using graphene

We theoretically demonstrate a high-sensitivity graphene-plasmon-based refractive index sensor working in the mid-infrared at room temperature. The bulk figure of merit of our sensor reaches values above 10, but the key aspect of our proposed plasmonic sensor is its surface sensitivity, which we examine in detail. We have used realistic values regarding doping level and electron relaxation time, which is the limiting factor for the sensor performance. Our results show quantitatively the high performance of graphene-plasmon-based refractive index sensors working in the mid-infrared.
Optical Quasi-periodic Oscillation of the BL Lacertae Object S5 0716+714 during the Faint State

In order to search for the evidence of quasi-periodic oscillation (QPO) in blazars, multicolor optical observations of the BL Lacertae object S5 0716+714 were performed from 2005 to 2012. For I band observations on 2010 March 19 with low variability amplitude and low flux level, the same QPO minutes at the 99% significance level is confirmed by the ZDCF method, Lomb–Scargle method, REDFIT, and fitting sinusoidal curves. The observed QPO is likely to be explained by accretion disk variability. If the observed QPO indicates an innermost stable orbital period from the accretion disk, the QPO ≃ 50 minutes corresponds to a black hole mass of for a non-rotating Schwarzschild black hole and for a maximally rotating Kerr black hole.