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The Weyl type $f(Q,T)$ modified gravity theory is an extension of the $f(Q)$ and $f(Q,T)$ type theories, where $T$ is the trace of the matter energy-momentum tensor, and the scalar non-metricity $Q$ is represented in its standard Weyl form, and it is fully determined by a vector field $\omega _\mu$. The theory can give a good description of the observational data, and of the evolution of the late-time Universe, including a geometric explanation of the dark energy. In this work we investigate the Big Bang Nucleosynthesis (BBN) constraints on several Weyl type $f(Q,T)$ gravity models. In particular, we consider the corrections that Weyl type $f(Q,T)$ terms induce on the freeze-out temperature $\mathcal{T}_f$, as compared to the standard $\Lambda$CDM results. We analyze in detail three distinct cosmological models, corresponding to specific choices of the functional form of $f(Q,T)$. The first model has a simple linear additive structure in $Q$ and $T$, the second model is multiplicative in $Q$ and $T$, while the third is additive in $T$ and the exponential of $Q$. For each $f(Q,T)$ we consider first the cosmological evolution in the radiation dominated era, and then we impose the observational bound on $\left|\delta \mathcal{T}_f/ \mathcal{T}_f\right|$ to obtain constraints on the model parameters from the primordial abundances of the light elements such as helium-4, deuterium and lithium-7. The abundances of helium-4 and deuterium agree with theoretical predictions, however, the lithium problem, even slightly alleviated, still persists for the considered Weyl type $f(Q,T)$ models. Generally, these models satisfy the BBN constraints, and thus they represent viable cosmologies describing the entire dynamical time scale of the evolution of the Universe., Comment: 19 pages, 12 figures

Accurately characterizing intrinsic stellar photometric noise induced by stellar astrophysics, such as stellar activity, granulation, and oscillations, is of crucial importance for detecting transiting exoplanets. In this study, we investigate the relation between the intrinsic stellar photometric noise, as quantified by the Kepler rrmsCDPP measurement, and the level of stellar chromospheric activity, as indicated by the S-index of Ca II HK lines derived from the LAMOST spectra. Our results reveal a clear positive correlation between S-index and rrmsCDPP, and the correlation becomes more significant at higher activity levels and on longer timescales. We have therefore built an empirical relation between rrmsCDPP and S-index as well as Teff, logg, [Fe/H], and apparent magnitude with the XGBoost regression algorithm, using the LAMOST-Kepler common star sample as the training set. This method achieves a precision of ~20 ppm for inferring the intrinsic noise from the S-index and other stellar labels on a 6-hour integration duration. We have applied this empirical relation to the full LAMOST DR7 spectra database, and obtained the intrinsic noise predictions for 1,358,275 stars. The resultant catalog is publicly available and expected to be valuable for optimizing target selection for future exoplanet-hunting space missions, such as the Earth 2.0 mission., Comment: Accepted for publication in ApJS

BiTeI is a polar semiconductor with strong spin-orbit coupling (SOC) that produces large Rashba spin splitting. Due to its potential utility in spintronics and magnetoelectrics, it is essential to understand how defects impact the spin transport in this material. Using scanning tunneling microscopy and spectroscopy, we image ring-like charging states of single-atom defects on the iodine surface of BiTeI. We observe nanoscale variations in the Rashba energy around each defect, which we correlate with the local electric field extracted from the bias dependence of each ring radius. Our data demonstrate the local impact of atomic defects on the Rashba effect, which is both a challenge and an opportunity for the development of future nanoscale spintronic devices.

The network flow watermarking technique associates the two communicating parties by actively modifying certain characteristics of the stream generated by the sender so that it covertly carries some special marking information. Some curious users communicating with the hidden server as a Tor client may attempt de-anonymization attacks to uncover the real identity of the hidden server by using this technique. This compromises the privacy of the anonymized communication system. Therefore, we propose a defense scheme against flow watermarking. The scheme is based on deep neural networks and utilizes generative adversarial networks to convert the original Inter-Packet Delays (IPD) into new IPDs generated by the model. We also adopt the concept of adversarial attacks to ensure that the detector will produce an incorrect classification when detecting these new IPDs. This approach ensures that these IPDs are considered "clean", effectively covering the potential watermarks. This scheme is effective against time-based flow watermarking techniques.

Fluxgate sensors are widely used in the field of low frequency and weak vector magnetic field measurement because of their good performance, such as high resolution and low power consumption. However, during the long-term continuous observation, the drift errors of the fluxgate sensor will occur due to the variable ambient temperature. This paper proposes a temperature compensation method for fluxgate sensors based on polynomial fitting. First, a physical model of the temperature & fluxgate sensor was established on the COMSOL Multiphysics simulation platform, and the influence of temperature on the measurement performance of the fluxgate sensor was analyzed. Second, according to the existing temperature-magnetic field data, a temperature compensation model of the fluxgate sensor was constructed. And compared it with other temperature compensation method, the result shows that the proposed temperature compensation method is relatively simple and can better achieve real-time compensation for sensor application scenarios. Finally, to verify the effectiveness of the proposed method, numerous laboratory experiments were implemented. The temperature drift is reduced from more than 500 nT before compensation to about 1 nT. The results show that the proposed method has a good temperature compensation effect on the data measured by the fluxgate sensor within a variable temperature background., Comment: An error occurred in the model section

We present the results of time-resolved high-resolution spectroscopic observations of the very active RS Canum Venaticorum (RS CVn) star SZ Piscium (SZ Psc), obtained during two consecutive observing nights on October 24 and 25, 2011. Several optical chromospheric activity indicators are analyzed using the spectral subtraction technique, which show the remarkably different behavior between two nights. Gradually blue-shifted and strengthened excess absorption features presented in the series of the subtracted spectra (especially for the H$_{\alpha}$, He I D$_{3}$ and H$_{\beta}$ lines), as a result of active stellar prominence that is rising its height along the line of our sight, was detected in the observations on October 24. This prominence activation event was probably associated with the subsequently occurred optical flare, and part of that flare decay phase was hunted in the observations on October 25. The flare was characterized by the prominent He I D$_{3}$ line emission, as well as stronger chromospheric emission in the H$_{\alpha}$, H$_{\beta}$ and other active lines. The gradual decay of flare was accompanied by an obviously developmental absorption feature in the blue wing of the H$_{\alpha}$ and other active lines, which could be explained as cool post-flare loops which projected against the bright flare background. Therefore, a series of possibly associated magnetic activity phenomena, including flare-related prominence activation, optical flare and post-flare loops, were detected during our observations.

Since the discovery of the first hot Jupiter orbiting a solar-type star, 51 Peg, in 1995, more than 4000 exoplanets have been identified using various observational techniques. The formation process of these sub-Earths remains elusive, and acquiring additional samples is essential for investigating this unique population. In our study, we employ a novel GPU Phase Folding algorithm combined with a Convolutional Neural Network, termed the GPFC method, on Kepler photometry data. This method enhances the transit search speed significantly over the traditional Box-fitting Least Squares method, allowing a complete search of the known KOI photometry data within hours using a commercial GPU card. To date, we have identified five promising sub-Earth short-period candidates: K00446.c, K01821.b, K01522.c, K03404.b, and K04978.b. A closer analysis reveals the following characteristics: K00446.c orbits a K dwarf on a 0.645091-day period. With a radius of $0.461R_\oplus$, it ranks as the second smallest USP discovered to date. K01821.b is a sub-Earth with a radius of $0.648R_\oplus$, orbiting a G dwarf over a 0.91978-day period. It is the second smallest USP among all confirmed USPs orbiting G dwarfs in the NASA Archive. K01522.c has a radius of $0.704 R_\oplus$ and completes an orbit around a Sun-like G dwarf in 0.64672 days; K03404.b, with a radius of $0.738 R_\oplus$, orbits a G dwarf on a 0.68074-day period; and K04978.b, with its planetary radius of $0.912 R_\oplus$, orbits a G dwarf, completing an orbit every 0.94197 days. Three of our finds, K01821.b, K01522.c and K03404.b, rank as the smallest planets among all confirmed USPs orbiting G dwarfs in the Kepler dataset. The discovery of these small exoplanets underscores the promising capability of the GPFC method for searching for small, new transiting exoplanets in photometry data from Kepler, TESS, and future space transit missions., Comment: 24 pages, 40 figures; To be published in the Monthly Notices of the Royal Astronomical Society (MNRAS)

This paper presents GPFC, a novel Graphics Processing Unit (GPU) Phase Folding and Convolutional Neural Network (CNN) system to detect exoplanets using the transit method. We devise a fast folding algorithm parallelized on a GPU to amplify low signal-to-noise ratio transit signals, allowing a search at high precision and speed. A CNN trained on two million synthetic light curves reports a score indicating the likelihood of a planetary signal at each period. While the GPFC method has broad applicability across period ranges, this research specifically focuses on detecting ultra-short-period planets with orbital periods less than one day. GPFC improves on speed by three orders of magnitude over the predominant Box-fitting Least Squares (BLS) method. Our simulation results show GPFC achieves $97%$ training accuracy, higher true positive rate at the same false positive rate of detection, and higher precision at the same recall rate when compared to BLS. GPFC recovers $100\%$ of known ultra-short-period planets in $\textit{Kepler}$ light curves from a blind search. These results highlight the promise of GPFC as an alternative approach to the traditional BLS algorithm for finding new transiting exoplanets in data taken with $\textit{Kepler}$ and other space transit missions such as K2, TESS and future PLATO and Earth 2.0., Comment: 16 pages, 19 figures; Accepted for publication in the peer-reviewed journal, Monthly Notices of the Royal Astronomical Society (MNRAS), on January 20, 2024

City-scale outdoor thermal comfort diagnostics are essential for understanding actual heat stress. However, previous research primarily focused on the street scale. Here, we present the WRF-UCM-SOLWEIG framework to achieve fine-grained thermal comfort mapping at the city scale. The background climate condition affecting thermal comfort is simulated by the Weather Research and Forecasting (WRF) model coupled with the urban canopy model (UCM) at a local-scale (500m). The most dominant factor, mean radiant temperature, is simulated using the Solar and Longwave Environmental Irradiance Geometry (SOLWEIG) model at the micro-scale (10m). The Universal Thermal Climate Index (UTCI) is calculated based on the mean radiant temperature and local climate parameters. The influence of different ground surface materials, buildings, and tree canopies is simulated in the SOLWEIG model using integrated urban morphological data. We applied this proposed framework to the city of Guangzhou, China, and investigated the intra-day variation in the impact of urban morphology during a heat wave period. Through statistical analysis, we found that the elevation in UTCI is primarily attributed to the increase in the fraction of impervious surface (ISF) during daytime, with a maximum correlation coefficient of 0.80. Tree canopy cover has a persistent cooling effect during the day. Implementing 40% of tree cover can reduce the daytime UTCI by 1.5 to 2.0 K. At nighttime, all urban features have a negligible contribution to outdoor thermal comfort. Overall, the established framework provides essential input data and references for studies and urban planners in the practice of urban (micro)climate diagnostics and planning.

Bogoliubov quasiparticles play a crucial role in understanding the behavior of a superconductor, and in achieving reliable operations of superconducting quantum circuits. Diagnosis of quasiparticle poisoning at the nanoscale provides invaluable benefits in designing superconducting qubits. Here, we use scanning tunneling noise microscopy to locally quantify quasiparticles by measuring the effective charge. Using the vortex lattice as a model system, we directly visualize the spatial variation of the quasiparticle concentration around superconducting vortices, which can be described within the Ginzburg-Landau framework. This shows a direct, noninvasive approach for the atomic-scale detection of relative quasiparticle concentration as small as 10-4 in various superconducting qubit systems. Our results alert of a quick increase in quasiparticle concentration with decreasing intervortex distance in vortex-based Majorana qubits., Comment: 11 pages, 4 figures

We report discoveries of 165 new quasar Ca II absorbers from the Sloan Digital Sky Survey (SDSS) Data Release 7 and 12. Our Ca II rest frame equivalent width distribution supports the weak and strong subpopulations, split at ${W}^{\lambda3934}_{0}=0.7${\AA}. Comparison of both populations' dust depletion shows clear consistency for weak absorber association with halo-type gas in the Milky Way (MW) while strong absorbers have environments consistent with halo and disc-type gas. We probed our high redshift Ca II absorbers for 2175{\AA} dust bumps, discovering 12 2175{\AA} dust absorbers (2DAs). This clearly shows that some Ca II absorbers follow the Large Magellanic Cloud (LMC) extinction law rather than the Small Magellanic Cloud extinction law. About 33% of our strong Ca II absorbers exhibit the 2175{\AA} dust bump while only 6% of weak Ca II absorbers show this bump. 2DA detection further supports the theory that strong Ca II absorbers are associated with disk components and are dustier than the weak population. Comparing average Ca II absorber dust depletion patterns to that of Damped Ly{\alpha} Absorbers (DLAs), Mg II absorbers, and 2DAs shows that Ca II absorbers generally have environments with more dust than DLAs and Mg II absorbers, but less dust than 2DAs. Comparing 2175{\AA} dust bump strengths from different samples and also the MW and LMC, the bump strength appears to grow stronger as the redshift decreases, indicating dust growth and the global chemical enrichment of galaxies in the universe over time., Comment: 17 pages, 24 figures, 5 tables; Acccepted for publication in the Monthly Notices of the Royal Astronomical Society (MNRAS)

Quasar absorption line analysis is critical for studying gas and dust components and their physical and chemical properties as well as the evolution and formation of galaxies in the early universe. Ca II absorbers, which are one of the dustiest absorbers and are located at lower redshifts than most other absorbers, are especially valuable when studying physical processes and conditions in recent galaxies. However, the number of known quasar Ca II absorbers is relatively low due to the difficulty of detecting them with traditional methods. In this work, we developed an accurate and quick approach to search for Ca II absorption lines using deep learning. In our deep learning model, a convolutional neural network, tuned using simulated data, is used for the classification task. The simulated training data are generated by inserting artificial Ca II absorption lines into original quasar spectra from the Sloan Digital Sky Survey (SDSS) whilst an existing Ca II catalog is adopted as the test set. The resulting model achieves an accuracy of 96% on the real data in the test set. Our solution runs thousands of times faster than traditional methods, taking a fraction of a second to analyze thousands of quasars while traditional methods may take days to weeks. The trained neural network is applied to quasar spectra from SDSS's DR7 and DR12 and discovered 399 new quasar Ca II absorbers. In addition, we confirmed 409 known quasar Ca II absorbers identified previously by other research groups through traditional methods., Comment: 15 pages, 15 figures, 5 tables; To be published in the Monthly Notices of the Royal Astronomical Society (MNRAS)

We derive several vanishing theorems for genera under almost nonnegative Ricci curvature and infinite fundamental group, which includes Todd genus, $\widehat{A}$-genus, elliptic genera and Witten genus. A vanishing theorem of Euler characteristic number for almost nonnegatively curved Alexandrov spaces is also proved.

Although many near-Earth objects have been found by ground-based telescopes, some fast-moving ones, especially those near detection limits, have been missed by observatories. We developed a convolutional neural network for detecting faint fast-moving near-Earth objects. It was trained with artificial streaks generated from simulations and was able to find these asteroid streaks with an accuracy of 98.7% and a false positive rate of 0.02% on simulated data. This program was used to search image data from the Zwicky Transient Facility (ZTF) in four nights in 2019, and it identified six previously undiscovered asteroids. The visual magnitudes of our detections range from ~19.0 - 20.3 and motion rates range from ~6.8 - 24 deg/day, which is very faint compared to other ZTF detections moving at similar motion rates. Our asteroids are also ~1 - 51 m diameter in size and ~5 - 60 lunar distances away at close approach, assuming their albedo values follow the albedo distribution function of known asteroids. The use of a purely simulated dataset to train our model enables the program to gain sensitivity in detecting faint and fast-moving objects while still being able to recover nearly all discoveries made by previously designed neural networks which used real detections to train neural networks. Our approach can be adopted by any observatory for detecting fast-moving asteroid streaks., Comment: 14 pages, 22 Figures, 4 Tables; To be published in the Monthly Notices of the Royal Astronomical Society (MNRAS)

We propose to develop a wide-field and ultra-high-precision photometric survey mission, temporarily named "Earth 2.0 (ET)". This mission is designed to measure, for the first time, the occurrence rate and the orbital distributions of Earth-sized planets. ET consists of seven 30cm telescopes, to be launched to the Earth-Sun's L2 point. Six of these are transit telescopes with a field of view of 500 square degrees. Staring in the direction that encompasses the original Kepler field for four continuous years, this monitoring will return tens of thousands of transiting planets, including the elusive Earth twins orbiting solar-type stars. The seventh telescope is a 30cm microlensing telescope that will monitor an area of 4 square degrees toward the galactic bulge. This, combined with simultaneous ground-based KMTNet observations, will measure masses for hundreds of long-period and free-floating planets. Together, the transit and the microlensing telescopes will revolutionize our understandings of terrestrial planets across a large swath of orbital distances and free space. In addition, the survey data will also facilitate studies in the fields of asteroseismology, Galactic archeology, time-domain sciences, and black holes in binaries., Comment: 116 pages,79 figures

Majorana bound states are putative collective excitations in solids that exhibit the self-conjugate property of Majorana fermions - they are their own antiparticles. In iron-based superconductors, zero-energy states in vortices have been reported as potential Majorana bound states, but the evidence remains controversial. Here, we use scanning tunneling noise spectroscopy to study the tunneling process into vortex bound states in the conventional superconductor NbSe2, and in the putative Majorana platform FeTe0.55Se0.45. We find that tunneling into vortex bound states in both cases exhibits charge transfer of a single electron charge. Our data for the zero-energy bound states in FeTe0.55Se0.45 exclude the possibility of Yu-Shiba-Rusinov states and are consistent with both Majorana bound states and trivial vortex bound states. Our results open an avenue for investigating the exotic states in vortex cores and for future Majorana devices, although further theoretical investigations involving charge dynamics and superconducting tips are necessary., Comment: 15 pages, 4 figures, and 16 pages for supplementary information

The cuprate high-temperature superconductors exhibit many unexplained electronic phases, but it was often thought that the superconductivity at sufficiently high doping is governed by conventional mean-field Bardeen-Cooper-Schrieffer (BCS) theory[1]. However, recent measurements show that the number of paired electrons (the superfluid density) vanishes when the transition temperature Tc goes to zero[2], in contradiction to expectation from BCS theory. The origin of this anomalous vanishing is unknown. Our scanning tunneling spectroscopy measurements in the overdoped regime of the (Pb,Bi)2Sr2CuO6+{\delta} high-temperature superconductor show that it is due to the emergence of puddled superconductivity, featuring nanoscale superconducting islands in a metallic matrix[3,4]. Our measurements further reveal that this puddling is driven by gap filling, while the gap itself persists beyond the breakdown of superconductivity. The important implication is that it is not a diminishing pairing interaction that causes the breakdown of superconductivity. Unexpectedly, the measured gap-to-filling correlation also reveals that pair-breaking by disorder does not play a dominant role and that the mechanism of superconductivity in overdoped cuprate superconductors is qualitatively different from conventional mean-field theory.

To investigate the properties of dust in the nuclear region of quasars, we explored the extinction curves of the iron low-ionization broad absorption line (FeLoBAL) quasar SDSS J163004.29+311957.6 and its two analogues. The parameterized extinction curves indicated the Milky Way-like 2175 \AA~ bump features in underlying extinction, which are similar to those seen in the Local Group and a subset of high-redshift star-forming galaxies. Compared to the bump features in the Large Magellanic Clouds (LMC), the detections in this work are much closer to those in the Milky Way (MW). These bump features, as well as those in the high- and low-ionization broad absorption line (BAL) quasars of Zhang et al., are probably the counterpart of the 2175 \AA~ bump features in the quasar environment. This type of dust grain is generally small, easily disrupted by high-energy photons and has difficulty surviving in the radiation field of the active galactic nucleus (AGN). However, due to the presence of absorption-line outflows, the 2175 \AA~ bump feature in quasars, which should be rare, is seen many times in BAL quasars. The shielding effect of outflow clouds allows the MW-like dust grains to be assembled or extends the survival period in the quasar nuclear region. The process, and physical and chemical conditions deserve further observational study and investigation., Comment: 13 pages, 10 figures. Accepted by Astronomy & Astrophysics

We present 2,241 exoplanet candidates identified with data from the Transiting Exoplanet Survey Satellite (TESS) during its two-year prime mission. We list these candidates in the TESS Objects of Interest (TOI) Catalog, which includes both new planet candidates found by TESS and previously-known planets recovered by TESS observations. We describe the process used to identify TOIs and investigate the characteristics of the new planet candidates, and discuss some notable TESS planet discoveries. The TOI Catalog includes an unprecedented number of small planet candidates around nearby bright stars, which are well-suited for detailed follow-up observations. The TESS data products for the Prime Mission (Sectors 1-26), including the TOI Catalog, light curves, full-frame images, and target pixel files, are publicly available on the Mikulski Archive for Space Telescopes., Comment: 39 pages, 16 figures. The Prime Mission TOI Catalog is included in the ancillary data as a CSV. For the most up-to-date catalog, refer to https://tess.mit.edu/toi-releases/

In this note, we study the Gehring link problem in the round sphere, which motives our study of the width of a band in positively curved manifolds. Using the same idea, we are able to get a sphere theorem for hypersurface in in the round $S^{n}$ in terms of its focal radius as well as the rigidity of Clifford hypersurface in $S^{n}$. The $3$-dimension case of our theorems confirm two conjectures raised by Gromov in [Gro18].

The idea that preformed Cooper pairs could exist in a superconductor above its zero-resistance state has been explored for unconventional, interface, and disordered superconductors, yet direct experimental evidence is lacking. Here, we use scanning tunneling noise spectroscopy to unambiguously show that preformed Cooper pairs exist up to temperatures much higher than the zero-resistance critical temperature $T_{C}$ in the disordered superconductor titanium nitride, by observing a clear enhancement in the shot noise that is equivalent to a change of the effective charge from 1 to 2 electron charges. We further show that spectroscopic gap fills up rather than closes when increasing temperature. Our results thus demonstrate the existence of a novel state above $T_{C}$ that, much like an ordinary metal, has no (pseudo)gap, but carries charge via paired electrons.

A conjecture of Burns and Knieper asks whether a 2-plane with a metric without conjugate points, and with a geodesic foliation whose lines are at bounded Hausdorff distance, is necessarily flat. We prove this conjecture in two cases: under the hypothesis that the plane admits total curvature, and under the hypothesis of visibility at some point. Along the way, we show that all geodesic line foliations on a Riemannian 2-plane must be homeomorphic to the standard one.

In this note, we estimate the upper bound of volume of closed positively or nonnegatively curved Alexandrov space $X$ with strictly convex boundary. We also discuss the equality case. In particular, the Boundary Conjecture holds when the volume upper bound is achieved. Our theorem also can be applied to Riemannian manifolds with non-smooth boundary, which generalizes Heintze and Karcher's classical volume comparison theorem. Our main tool is the gradient flow of semi-concave functions.

Magnetic sensing platform techniques have been used in many years in an attempt to better evaluate the likelihood of recoverable hydrocarbon reservoirs by determining the depth and pattern of sedimentary rock formations containing magnetic minerals, such as magnetite. Utilizing airplanes, large-area magnetic surveys have been conducted to estimate, for example, the depth of igneous rock and the thickness of sedimentary rock formations. In this case, the vector magnetic survey method can simultaneously obtain the modulus and direction information of the Earth's magnetic field, which can effectively reduce the multiplicity on data inversion, contribute to the quantitative interpretation of the magnetic body and obtain more precise information and characteristics of magnetic field resource, so as to improve the detection resolution and positioning accuracy of the underground target body. This paper presents a state-of-the-art review of the application situations, the technical features, and the development of the vector magnetic sensing platform-technical aspects for different application scenarios, i.e., ground, wells, marine, airborne, and satellites, respectively. The potential of multi-survey sensing platform technique fusion for magnetic field detection is also discussed., Comment: 2 columns, 16 pages, 15 figures

In this paper we discuss the sufficient and necessary conditions for multiple Alexandrov spaces being glued to an Alexandrov space. We propose a Gluing Conjecture, which says that the finite gluing of Alexandrov spaces is an Alexandrov space, if and only if the gluing is by path isometry along the boundaries and the tangent cones are glued to Alexandrov spaces. This generalizes Petrunin's Gluing Theorem. Under the assumptions of the Gluing Conjecture, we classify the $2$-point gluing over $(n-1,\epsilon)$-regular points as local separable gluing and the gluing near un-glued $(n-1,\epsilon)$-regular points as local involutional gluing. We also prove that the Gluing Conjecture is true if the complement of $(n-1,\epsilon)$-regular points is discrete in the glued boundary. In particular, this implies the general Gluing Conjecture as well as a new Gluing Theorem in dimension 2., Comment: 23 pages, 2 figures

We report the detection of a large amplitude MIR outburst in the white dwarf (WD) 0145+234 in the NEOWISE Survey data. The source had a stable MIR flux before 2018, and was brightened by about 1.0 magnitude in the W1 and W2 bands within half a year and has been continuously brightening since then. No significant variations are found in the optical photometry data during the same period. This suggests that this MIR outburst is caused by recent replenishing or redistribution of dust, rather than intrinsic variations of the WD. SED modeling of 0145+234 suggests that there was already a dust disk around the WD in the quiescent state, and both of the temperature and surface area of the disk evolved rapidly since the outburst. The dust temperature was about 1770K in the initial rising phase, close to the sublimation temperature of silicate grains, and gradually cooled down to around 1150K, while the surface area increased by a factor of about 6 during the same period. The inferred closest distance of dust to the WD is within the tidal disruption radius of a gravitationally bounded asteroid. We estimated the dust mass to be between $3\times10^{15}$ to $3\times10^{17}$ $\rho/(1 \mathrm g~cm^{-3})$ kg for silicate grains of a power-law size distribution with a high cutoff size from 0.1 to 1000 microns. We interpret this as a possible tidal breakup of an exo-asteroid by the WD. Further follow-up observations of this rare event may provide insights on the origin of dust disk and metal pollution in some white dwarfs., Comment: Comments are welcomed. Resubmitted to ApJL after addressing referee's comments

Quasars are high-luminosity active galactic nuclei believed to be powered by accretion of interstellar matter onto a super-massive black hole (SMBH) therein. Most of the observed energy is released in an accretion disk of inspiralling gas surrounding the SMBH. An enormous amount of fueling material is expected to be transported inwards. However, basic questions remain unanswered as to whether and how the accretion disks are supplied with external gas, since no disk-feeding inflow has hitherto been observed clearly. Here we report the discovery of highly redshifted broad absorption lines arising from neutral hydrogen and helium atoms in a small sample of quasars. Their absorption troughs show a broad range of Doppler velocities from zero extending continuously inward up to as high as $\sim 5,000$ km s$^{-1}$. We thus see through streams of cold gas moving with a radially inward velocity component that spans an immense gradient---a result of gravitational acceleration by the central SMBH. Extensive photo-ionization modeling for the archetypical object SDSS J103516.20+142200.6 indicates the inflowing gas to be dense, thick and moderately ionized, with a characteristic distance to the SMBH of $\sim 1,000$ gravitational radii, possibly overlapping or close to the outer accretion disk. Our results present the first compelling evidence for the long-sought inflow directly feeding quasars' accretion disks with external materials, likely originating from the dusty torus at a parsec scale. Our approach provides a new tool to probe the bulk of the so far elusive fueling inflows in quasars. Their studies may help address some of the fundamental questions concerning accretion physics, the onset and sustainment of quasar activity, and the SMBH growth at centers of most galaxies., Comment: 38 pages, 15 figures, pre-print of an article published in Nature

A point charge near the surface of a topological insulator (TI) with broken time-reversal symmetry is predicted to generate an image magnetic charge in addition to an image electric charge. We use scanning tunneling spectroscopy to study the image potential states (IPS) of the topological semimetal Sb(111) surface. We observe five IPS with discrete energy levels that are well described by a one-dimensional model. The spatial variation of the IPS energies and lifetimes near surface step edges shows the first local signature of resonant interband scattering between IPS, which suggests that image charges too may interact. Our work motivates the exploration of the TI surface geometry necessary to realize and manipulate a magnetic charge., Comment: 6 pages, 6 figures

Metal absorption line systems in distant quasar spectra probe of the history of gas content in the universe. The MgII $\lambda \lambda$ 2796, 2803 doublet is one of the most important absorption lines since it is a proxy of the star formation rate and a tracer of the cold gas associated with high redshift galaxies. Machine learning algorithms have been used to detect absorption lines systems in large sky surveys, such as Principle Component Analysis (PCA), Gaussian Process (GP) and decision trees. A very powerful algorithm in the field of machine learning called deep neural networks, or '' deep learning'' is a new structure of neural network that automatically extracts semantic features from raw data and represents them at a high level. In this paper, we apply a deep convolutional neural network for absorption line detection. We use the previously published DR7 MgII catalog (Zhu et al. 2013) as the training and validation sample and the DR12 MgII catalog as the test set. Our deep learning algorithm is capable of detecting MgII absorption lines with an accuracy of $\sim$94% . It takes only $\sim 9$ seconds to analyze $\sim$ 50000 quasar spectra with our deep neural network, which is ten thousand times faster than traditional methods, while preserving high accuracy with little human interference. Our study shows that Mg II absorption line detection accuracy of a deep neutral network model strongly depends on the filter size in the filter layer of the neural network, and the best results are obtained when the filter size closely matches the absorption feature size., Comment: 14 pages, 9 figures, 3 tables, Accepted for publication in Monthly Notices of the Royal Astronomical Society

TOU is an extremely high resolution optical spectrograph (R=$100,000$, 380-900~nm), which is designed to detect low mass exoplanets using the radial velocity technique.We describe an IDL-based radial velocity (RV) data reduction pipeline for the TOU spectrograph and its performance with stable stars. This pipeline uses a least-squares fitting algorithm to match observed stellar spectra to a high signal-to-noise template created for each star. By carefully controlling all of the error contributions to RV measurements in both the hardware and data pipeline, we have achieved $\sim$0.9\ms long-term RV precision with one of the most RV stable stars, Tau Ceti, similar to what has been achieved with HARPS. This paper presents steps and details in our data pipeline on how to reach the \sms RV precision and also all major error sources which contribute to the final RV measurement uncertainties. The lessons learned in this pipeline development can be applied to other environmentally controlled, very high resolution optical spectrographs to improve RV precision., Comment: 12 pages, 12 figures, Accepted for publication in MNRAS

In this note, we study the radius of positively curved or non-negatively curved Alexandrov space with strictly convex boundary, with convexity measured by the Base-Angle defined by Alexander and Bishop. We also estimate the volume of the boundary of non-negatively curved spaces as well as the rigidity case, which can be thought as a non-negatively curved version of a recent result of Grove-Petersen.

Inspired by a recent work of Grove-Petersen in [GP18], where the authors studied Alexandrov spaces with largest possible boundary. We study Alexandrov spaces with lower curvature bound 1 and with small boundary. When the radius of X is \pi/2, and the boundary has diameter \pi/2, we classify the total space X.

Studying the stellar mass, age, luminosity, star-formation rate, and impact parameter of quasar absorber host galaxies can aid in the understanding of galaxy formation and evolution as well as in testing their models. We derive the Spectral Energy Distribution (SED) and impact parameter limits of low redshift ($z_{abs} = 0.37 - 0.55$) Mg II absorbers and of higher redshift ($z_{abs} = 1.0 - 2.5$) 2175 \AA\ dust absorbers (2DAs). We use an imaging stacking technique to statistically boost the signal-to-noise ratio (SNR) to increase detection of the absorber host galaxies. The point spread function of the background quasar is modeled with Principal Component Analysis (PCA). This method efficiently reduces the uncertainty of traditional PSF modeling. Our SED for Mg II absorbers indicates that low redshift Mg II absorber host galaxies are likely star-forming galaxies transitioning into red quiescent galaxies, with a low star formation rate of 2.2 $M_\odot$ $yr^{-1}$. From the stacked images and simulations, we show that the average impact parameter of 2DAs is > 5 times smaller than that of Mg II absorbers, at < 7 kpc instead of Mg II absorbers' 48 kpc, indicating that 2DAs are likely associated with disk components of high redshift galaxies. This means that 2DAs are likely good probes to study precursors to the Milky Way., Comment: 19 pages, 14 figures, accepted by MNRAS. arXiv admin note: text overlap with arXiv:astro-ph/0609760 by other authors

The Dharma Planet Survey (DPS) aims to monitor about 150 nearby very bright FGKM dwarfs (within 50 pc) during 2016$-$2020 for low-mass planet detection and characterization using the TOU very high resolution optical spectrograph (R$\approx$100,000, 380-900nm). TOU was initially mounted to the 2-m Automatic Spectroscopic Telescope at Fairborn Observatory in 2013-2015 to conduct a pilot survey, then moved to the dedicated 50-inch automatic telescope on Mt. Lemmon in 2016 to launch the survey. Here we report the first planet detection from DPS, a super-Earth candidate orbiting a bright K dwarf star, HD 26965. It is the second brightest star ($V=4.4$ mag) on the sky with a super-Earth candidate. The planet candidate has a mass of 8.47$\pm0.47M_{\rm Earth}$, period of $42.38\pm0.01$ d, and eccentricity of $0.04^{+0.05}_{-0.03}$. This RV signal was independently detected by Diaz et al. (2018), but they could not confirm if the signal is from a planet or from stellar activity. The orbital period of the planet is close to the rotation period of the star (39$-$44.5 d) measured from stellar activity indicators. Our high precision photometric campaign and line bisector analysis of this star do not find any significant variations at the orbital period. Stellar RV jitters modeled from star spots and convection inhibition are also not strong enough to explain the RV signal detected. After further comparing RV data from the star's active magnetic phase and quiet magnetic phase, we conclude that the RV signal is due to planetary-reflex motion and not stellar activity., Comment: 13 pages, 17 figures, Accepted for publication in MNRAS

We report the first detection of the host galaxy of a strong 2175 \AA$ $ dust absorber at z = 2.12 towards the background quasar SDSS J121143.42+083349.7 using HST/WFC3 IR F140W direct imaging and G141 grism spectroscopy. The spectroscopically confirmed host galaxy is located at a small impact parameter of ~ 5.5 kpc (~ 0.65$''$). The F140W image reveals a disk-like morphology with an effective radius of 2.24 $\pm$ 0.08 kpc. The extracted 1D spectrum is dominated by a continuum with weak emission lines ([O\III] and [O\II]). The [O\III]-based unobscured star formation rate (SFR) is 9.4 $\pm$ 2.6 M$_{\odot}$yr$^{-1}$ assuming an [O\III]/H$\alpha$ ratio of 1. The moderate 4000 \AA$ $ break (Dn(4000) index $\sim$ 1.3) and Balmer absorption lines indicate that the host galaxy contains an evolved stellar population with an estimated stellar mass M$_*$ of (3 - 7) $\times$ 10$^{10}$ M$_{\odot}$. The SFR and M$_*$ of the host galaxy are comparable to, though slightly lower than, those of typical emission-selected galaxies at $z$ $\sim$ 2. As inferred from our absorption analysis in Ma et al. (2015, 2017, 2018), the host galaxy is confirmed to be a chemically-enriched, evolved, massive, and star-forming disk-like galaxy that is likely in the transition from a blue star-forming galaxy to a red quiescent galaxy., Comment: 7 pages, 4 figures; accepted for publication in ApJL

Combining stellar atmospheric parameters, such as effective temperature, surface gravity, and metallicity, with barycentric radial velocity data provides insight into the chemo-dynamics of the Milky Way and our local Galactic environment. We analyze 3075 stars with spectroscopic data from the Sloan Digital Sky Survey III (SDSS-III) MARVELS radial velocity survey and present atmospheric parameters for 2343 dwarf stars using the spectral indices method, a modified version of the equivalent width method. We present barycentric radial velocities for a sample of 2610 stars with a median uncertainty of 0.3 km s$^{-1}$. We determine stellar ages using two independent methods and calculate ages for 2335 stars with a maximum-likelihood isochronal age-dating method and for 2194 stars with a Bayesian age-dating method. Using previously published parallax data we compute Galactic orbits and space velocities for 2504 stars to explore stellar populations based on kinematic and age parameters. This study combines good ages and exquisite velocities to explore local chemo-kinematics of the Milky Way, which complements many of the recent studies of giant stars with the APOGEE survey, and we find our results to be in agreement with current chemo-dynamical models of the Milky Way. Particularly, we find from our metallicity distributions and velocity-age relations of a kinematically-defined thin disk that the metal rich end has stars of all ages, even after we clean the sample of highly eccentric stars, suggesting that radial migration plays a key role in the metallicity scatter of the thin disk. All stellar parameters and kinematic data derived in this work are catalogued and published online in machine-readable form., Comment: 22 pages, 28 figures, Accepted by MNRAS 2018 August 31

We have carried out an approximate analytical solution to precisely consider the influence of magnetic field on the transverse oscillation of particles in cyclotron. The differential equations of transverse oscillation are solved from the Lindstedt-Poincare method. After careful deduction, the accurate first order analytic solutions are obtained. The analytical solutions are applied to the magnetic field, comes from an isochronous cyclotron with four spiral sectors, the accuracy of these analytical solutions is verified and confirmed from the comparison of numerical method. Finally, we discussed the transverse oscillation at v0=N/2 , using the same analytical solution., Comment: This peper will be published in Chinese Physics C

We present the cold neutral content (H I and C I gas) of 13 quasar 2175 \AA$ $ dust absorbers (2DAs) at $z$ = 1.6 - 2.5 to investigate the correlation between the presence of the UV extinction bump with other physical characteristics. These 2DAs were initially selected from the Sloan Digital Sky Surveys I - III and followed up with the Keck-II telescope and the Multiple Mirror Telescope as detailed in our Paper I. We perform a correlation analysis between metallicity, redshift, depletion level, velocity width, and explore relationships between 2DAs and other absorption line systems. The 2DAs on average have higher metallicity, higher depletion levels, and larger velocity widths than Damped Lyman-$\alpha$ absorbers (DLAs) or subDLAs. The correlation between [Zn/H] and [Fe/Zn] or [Zn/H] and log$\Delta$V$_{90}$ can be used as alternative stellar mass estimators based on the well-established mass-metallicity relation. The estimated stellar masses of the 2DAs in this sample are in the range of $\sim$ 10$^9$ to $\sim$2 $\times$ 10$^{11}$ $M_{\odot}$ with a median value of $\sim$2 $\times$ 10$^{10}$ $M_{\odot}$. The relationship with other quasar absorption line systems can be described as (1) 2DAs are a subset of Mg II and Fe II absorbers, (2) 2DAs are preferentially metal-strong DLAs/subDLAs, (3) More importantly, all of the 2DAs show C I detections with logN(C I) $>$ 14.0 cm$^{-2}$, (4) 2DAs can be used as molecular gas tracers. Their host galaxies are likely to be chemically enriched, evolved, massive (more massive than typical DLA/subDLA galaxies), and presumably star-forming galaxies., Comment: 12 pages, 11 figures; accepted for publication in MNRAS

We present 13 new 2175 {\AA} dust absorbers at z_abs = 1.0 - 2.2 towards background quasars from the Sloan Digital Sky Survey. These absorbers are examined in detail using data from the Echelle Spectrograph and Imager (ESI) on the Keck II telescope. Many low-ionization lines including Fe II, Zn II, Mg II, Si II, Al II, Ni II, Mn II, Cr II, Ti II, and Ca II are present in the same absorber which gives rise to the 2175 {\AA} bump. The relative metal abundances (with respect to Zn) demonstrate that the depletion patterns of our 2175 {\AA} dust absorbers resemble that of the Milky Way clouds although some are disk-like and some are halo-like. The 2175 {\AA} dust absorbers have significantly higher depletion levels compared to literature Damped Lyman-{\alpha} absorbers (DLAs) and subDLAs. The dust depletion level indicator [Fe/Zn] tends to anti-correlate with bump strengths. The velocity profiles from the Keck/ESI spectra also provide kinematical information on the dust absorbers. The dust absorbers are found to have multiple velocity components with velocity widths extending from ~100 to ~ 600 km/s, which are larger than those of most DLAs and subDLAs. Assuming the velocity width is a reliable tracer of stellar mass, the host galaxies of 2175 {\AA} dust absorbers are expected to be more massive than DLA/subDLA hosts. Not all of the 2175 {\AA} dust absorbers are intervening systems towards background quasars. The absorbers towards quasars J1006+1538 and J1047+3423 are proximate systems that could be associated with the quasar itself or the host galaxy., Comment: 27 pages, 32 figures, 31 tables; Accepted for publication in MNRAS

The parameters in a nuclear magnetic resonance (NMR) free induction decay (FID) signal contain information that is useful in magnetic field measurement, magnetic resonance sounding (MRS) and other related applications. A real time sampled FID signal is well modeled as a finite mixture of exponential sequences plus noise. We propose to use the Hilbert-Huang Transform (HHT) for noise reduction and characterization, where the generalized Hilbert-Huang represents a way to decompose a signal into so-called intrinsic mode function (IMF) along with a trend, and obtain instantaneous frequency data. Moreover, the HHT for an FID signal's feature analysis is applied for the first time. First, acquiring the actual untuned FID signal by a developed prototype of proton magnetometer, and then the empirical mode decomposition (EMD) is performed to decompose the noise and original FID. Finally, the HHT is applied to the obtained IMFs to extract the Hilbert energy spectrum, to indicate the energy distribution of the signal on the frequency axis. By theory analysis and the testing of an actual FID signal, the results show that, compared with general noise reduction methods such as auto correlation and singular value decomposition (SVD), combined with the proposed method can further suppress the interfered signals effectively, and can obtain different components of FID signal, which can use to identify the magnetic anomaly, the existence of groundwater etc. This is a very important property since it can be exploited to separate the FID signal from noise and to estimate exponential sequence parameters of FID signal., Comment: 14 pages, 6 figures, 3 tables

Broad absorption lines (BALs) found in a significant fraction of quasar spectra identify high-velocity outflows that might be present in all quasars and could be a major factor in feedback to galaxy evolution. Understanding the nature of these flows requires further constraints on their physical properties, including their column densities, for which well-studied BALs, such as CIV 1548,1551, typically provide only a lower limit because of saturation effects. Low-abundance lines, such as PV 1118,1128, indicate large column densities, implying outflows more powerful than measurements of CIV alone would indicate. We search through a sample of 2694 BAL quasars from the SDSS-III/BOSS DR9 quasar catalog for such absorption, and we identify 81 `definite' and 86 `probable' detections of PV broad absorption, yielding a firm lower limit of 3.0-6.2% for the incidence of such absorption among BAL quasars. The PV-detected quasars tend to have stronger CIV and SiIV absorption, as well as a higher incidence of LoBAL absorption, than the overall BAL quasar population. Many of the PV-detected quasars have CIV troughs that do not reach zero intensity (at velocities where PV is detected), confirming that the outflow gas only partially covers the UV continuum source. PV appears significantly in a composite spectrum of non-PV-detected BAL quasars, indicating that PV absorption (and large column densities) are much more common than indicated by our search results. Our sample of PV detections significantly increases the number of known PV detections, providing opportunities for follow-up studies to better understand BAL outflow energetics., Comment: 18 pages, 12 figures. All spectral plots available at http://www.dancapellupo.com/boss-pv-bal-spectral-plots.html

Planet searches using the radial velocity technique show a paucity of companions to solar-type stars within ~5 AU in the mass range of ~10 - 80 M$_{\text{Jup}}$. This deficit, known as the brown dwarf desert, currently has no conclusive explanation. New substellar companions in this region help asses the reality of the desert and provide insight to the formation and evolution of these objects. Here we present 10 new brown dwarf and two low-mass stellar companion candidates around solar-type stars from the Multi-object APO Radial-Velocity Exoplanet Large-Area Survey (MARVELS) of the Sloan Digital Sky Survey III (SDSS-III). These companions were selected from processed MARVELS data using the latest University of Florida Two Dimensional (UF2D) pipeline, which shows significant improvement and reduction of systematic errors over previous pipelines. The 10 brown dwarf companions range in mass from ~13 to 76 M$_{\text{Jup}}$ and have orbital radii of less than 1 AU. The two stellar companions have minimum masses of ~98 and 100 M$_{\text{Jup}}$. The host stars of the MARVELS brown dwarf sample have a mean metallicity of [Fe/H] = 0.03 $\pm$ 0.08 dex. Given our stellar sample we estimate the brown dwarf occurrence rate around solar-type stars with periods less than ~300 days to be ~0.56%., Comment: 20 pages, 22 figures, 3 tables

We prove that the Euclidean plane is the only Riemannian plane with total curvature and free of conjugate points that satisfies Playfair's version of the parallel postulate.

We study the mean absorption spectrum of the Damped Lyman alpha population at $z\sim 2.6$ by stacking normalized, rest-frame shifted spectra of $\sim 27\,000$ DLAs from the DR12 of BOSS/SDSS-III. We measure the equivalent widths of 50 individual metal absorption lines in 5 intervals of DLA hydrogen column density, 5 intervals of DLA redshift, and overall mean equivalent widths for an additional 13 absorption features from groups of strongly blended lines. The mean equivalent width of low-ionization lines increases with $N_{\rm HI}$, whereas for high-ionization lines the increase is much weaker. The mean metal line equivalent widths decrease by a factor $\sim 1.1-1.5$ from $z\sim2.1$ to $z \sim 3.5$, with small or no differences between low- and high-ionization species. We develop a theoretical model, inspired by the presence of multiple absorption components observed in high-resolution spectra, to infer mean metal column densities from the equivalent widths of partially saturated metal lines. We apply this model to 14 low-ionization species and to AlIII, SIII, SiIII, CIV, SiIV, NV and OVI. We use an approximate derivation for separating the equivalent width contributions of several lines to blended absorption features, and infer mean equivalent widths and column densities from lines of the additional species NI, ZnII, CII${}^{*}$, FeIII, and SIV. Several of these mean column densities of metal lines in DLAs are obtained for the first time; their values generally agree with measurements of individual DLAs from high-resolution, high signal-to-noise ratio spectra when they are available., Comment: Resubmitted after referee revision. Added evolution of metal-line equivalent widths with redshift (Section 5). Added assessment of result dependencies on sample and methodology. Comparison of relative abundances of DLAs vs Milky Way ISM and halo (Figure 16). Publicly available videos of composite quasar and DLA spectra realizations here: https://github.com/lluism/

We present the Data Release 12 Quasar catalog (DR12Q) from the Baryon Oscillation Spectroscopic Survey (BOSS) of the SDSS-III. This catalog includes all SDSS-III/BOSS objects that were spectroscopically targeted as quasar candidates during the full survey and that are confirmed as quasars via visual inspection of the spectra, have luminosities Mi[z=2]<-20.5 (in a LCDM cosmology with H_0 = 70 km/s/Mpc, Omega_M = 0.3, and Omega _L=0.7), and either display at least one emission line with a full width at half maximum (FWHM)larger than 500 km/s or, if not, have interesting/complex absorption features. The catalog also includes previously known quasars (mostly from SDSS-I and II) that were reobserved by BOSS. The catalog contains 297,301 quasars detected over 9,376 square degrees with robust identification and redshift measured by a combination of principal component eigenspectra. The number of quasars with z>2.15 is about an order of magnitude greater than the number of z>2.15 quasars known prior to BOSS. Redshifts and FWHMs are provided for the strongest emission lines (CIV, CIII], MgII). The catalog identifies 29,580 broad absorption line quasars and lists their characteristics. For each object, the catalog presents five-band (u, g, r, i, z) CCD-based photometry together with some information on the optical morphology and the selection criteria. When available, the catalog also provides information on the optical variability of quasars using SDSS and PTF multi-epoch photometry. The catalog also contains X-ray, ultraviolet, near-infrared, and radio emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra, covering the wavelength region 3,600-10,500A at a spectral resolution in the range 1,300

We report the detections of a giant planet (MARVELS-7b) and a brown dwarf candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. It is the first close binary system with more than one substellar circum-primary companion discovered to the best of our knowledge. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using ET at Kitt Peak National Observatory, HRS at HET, the "Classic" spectrograph at the Automatic Spectroscopic Telescope at Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period brown dwarf in this binary. HD 87646 is a close binary with a separation of $\sim22$ AU between the two stars, estimated using the Hipparcos catalogue and our newly acquired AO image from PALAO on the 200-inch Hale Telescope at Palomar. The primary star in the binary, HD 87646A, has Teff = 5770$\pm$80K, log(g)=4.1$\pm$0.1 and [Fe/H] = $-0.17\pm0.08$. The derived minimum masses of the two substellar companions of HD 87646A are 12.4$\pm$0.7M$_{\rm Jup}$ and 57.0$\pm3.7$M$_{\rm Jup}$. The periods are 13.481$\pm$0.001 days and 674$\pm$4 days and the measured eccentricities are 0.05$\pm$0.02 and 0.50$\pm$0.02 respectively. Our dynamical simulations show the system is stable if the binary orbit has a large semi-major axis and a low eccentricity, which can be verified with future astrometry observations., Comment: Accepted for publication at AJ. RV data are provided as ascii file in the source files

We present the effective temperatures ($T_{\rm eff}$), metallicities, and colours in SDSS, 2MASS, and WISE filters, of a sample of 3834 late-K and early-M dwarfs selected from the Sloan Digital Sky Survey APOGEE spectroscopic survey ASPCAP catalog. We confirm that ASPCAP $T_{\rm eff}$ values between 3550 K$

The Baryon Oscillation Spectroscopic Survey (BOSS) has collected more than 150,000 $2.1 \leq z \leq 3.5$ quasar spectra since 2009. Using this unprecedented sample, we create a composite spectrum in the rest-frame of 102,150 quasar spectra from 800 \AA\ to 3300 \AA\ at a signal-to-noise ratio close to 1000 per pixel ($\Delta v$ of 69 km~s$^{-1}$). Included in this analysis is a correction to account for flux calibration residuals in the BOSS spectrophotometry. We determine the spectral index as a function of redshift of the full sample, warp the composite spectrum to match the median spectral index, and compare the resulting spectrum to SDSS photometry used in target selection. The quasar composite matches the color of the quasar population to within 0.02 magnitudes in $g-r$, 0.03 magnitudes in $r-i$, and 0.01 magnitudes in $i-z$ over the redshift range $2.2

In its three years of operation, the Sloan Digital Sky Survey (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed $>$14,000 stars with enough epochs over a sufficient temporal baseline for the fitting of Keplerian orbits. We present the custom orbit-fitting pipeline used to create this catalog, which includes novel quality metrics that account for the phase and velocity coverage of a fitted Keplerian orbit. With a typical RV precision of $\sim100-200$ m s$^{-1}$, APOGEE can probe systems with small separation companions down to a few Jupiter masses. Here we present initial results from a catalog of 382 of the most compelling stellar and substellar companion candidates detected by APOGEE, which orbit a variety of host stars in diverse Galactic environments. Of these, 376 have no previously known small separation companion. The distribution of companion candidates in this catalog shows evidence for an extremely truncated brown dwarf (BD) desert with a paucity of BD companions only for systems with $a < 0.1-0.2$ AU, with no indication of a desert at larger orbital separation. We propose a few potential explanations of this result, some which invoke this catalog's many small separation companion candidates found orbiting evolved stars. Furthermore, 16 BD and planet candidates have been identified around metal-poor ([Fe/H] $< -0.5$) stars in this catalog, which may challenge the core accretion model for companions $>10 M_{Jup}$. Finally, we find all types of companions are ubiquitous throughout the Galactic disk with candidate planetary-mass and BD companions to distances of $\sim6$ and $\sim16$ kpc, respectively., Comment: 27 pages, 14 figures,Published in AJ 02/26/2015. Full catalog available will be available as a FITS binary table with published version, and is currently avaliable on Filtergraph at https://filtergraph.com/apOrbitPub

We present Keck/ESI long-slit spectroscopy of SBS 1421+511, a system consisting of a quasar at z = 0.276 and an extended source 3" northern to the quasar. The quasar shows a blue-skewed profile of Balmer broad emission lines, which can be well modeled as emissions from a circular disk with a blueshift velocity of ~1400 km/s. The blueshift is better interpreted as resulting from a recoiling active black hole than from a super-massive black hole binary, since the line profile almost kept steady over one decade in the quasar rest-frame. Alternative interpretations are possible as well, such as emissions from a bipolar outflow or a circular disk with spiral emissivity perturbations. The extended source shows Seyfert-like narrow line ratios and a [OIII] luminosity of >1.4\times10^8L_\odot, with almost the same redshift as the quasar and a projected distance of 12.5 kpc at the redshift. SBS 1421+511 is thus likely to be an interacting galaxy pair with dual AGN. Alternatively, the quasar companion only appears to be active but not necessarily so: the gas before/in/behind the companion galaxy is illuminated by the quasar as an extended emission line region is detected at a similar distance in the opposite direction southern to the quasar, which may be generated either by tidal interactions between the galaxy pair or large-scale outflows from the quasar., Comment: to be published in The Astrophysical Journal