Next generation ground-based gravitational-wave detectors will observe binary black hole (BBH) mergers up to redshift ##IMG## [http://ej.iop.org/images/0004-637X/898/2/152/apjab9b78ieqn1.gif] {$z\gtrsim 10$} , probing the evolution of compact binary (CB) mergers across cosmic time. Here, we present a new data-driven model to estimate the cosmic merger rate density (MRD) evolution of CBs, by coupling

Extensive progress has recently been made in our understanding of heavy-element production via the r -process in the universe, specifically with the first observed neutron star binary merger (NSBM) event associated with the gravitational-wave signal detected by LIGO, GW170817. The chemical abundance patterns of metal-poor r -process-enhanced stars provide key evidence for the dominant site(s) of the

Feedback is indispensable in galaxy formation. However, lacking resolutions, cosmological simulations often use ad hoc feedback parameters. Conversely, small-box simulations, while they better resolve the feedback, cannot capture gas evolution beyond the simulation domain. We aim to bridge the gap by implementing small-box results of supernovae-driven outflows into dark matter halo-scale simulations

The Vega planetary system hosts the archetype of extrasolar Kuiper belts and is rich in dust from the sub-astronomical unit region out to hundreds of astronomical units, suggesting intense dynamical activity. We present Atacama Large Millimeter/submillimeter Array (ALMA) millimeter observations that detect and resolve the outer dust belt from the star for the first time. The interferometric visibilities

We present a multiwavelength investigation of the radio galaxy population in the galaxy cluster MOO J1506+5137 at z = 1.09 ± 0.03, which in previous work we identified as having multiple complex radio sources. The combined data set used in this work includes data from the Low-Frequency Array Two-meter Sky Survey, NSF’s Karl G. Jansky Very Large Array, the Robert C. Byrd Green Bank Telescope, the Spitzer

The intergalactic medium is expected to clump on scales down to ##IMG## [http://ej.iop.org/images/0004-637X/898/2/149/apjab9f2fieqn1.gif] {${10}^{4}\mbox{--}{10}^{8}$} M ⊙ before the onset of reionization. The impact of these small-scale structures on reionization is poorly understood despite the modern understanding that gas clumpiness limits the growth of ##IMG## [http://ej.iop.org/images/0004-6

The carriers of the 21 and 30 μ m emission features in infrared spectra of circumstellar envelopes are a long-standing enigma. In this paper, we present the results of molecular line observations toward two circumstellar envelopes exhibiting the 21 and/or 30 μ m features, IRAS 21318+5631 and 22272+5435. We investigate whether they have unusual gas-phase chemistry and search for a possible gas-phase

The origin of multiple stellar populations in globular clusters (GCs) is one of the greatest mysteries of modern stellar astrophysics. N -body simulations suggest that the present-day dynamics of GC stars can constrain the events that occurred at high redshift and led to the formation of multiple populations. Here, we combine multiband photometry from the Hubble Space Telescope (HST) and ground-based

We present a systematic study of the X-ray binaries (XRBs) containing a black hole (BH) and a nondegenerate companion, in which mass transfer takes place via either capturing the companion’s wind or Roche lobe overflow (RLO). As shown in our previous work, which focused on the formation and evolution of detached BH binaries, our assumed models relevant to BHs’ progenitors predicted significantly different

We study the evolution of a minifilament eruption in a quiet region at the center of the solar disk and its impact on the ambient atmosphere. We used high spectral resolution imaging spectroscopy in H α acquired by the echelle spectrograph of the Vacuum Tower Telescope, Tenerife, Spain; photospheric magnetic field observations from the Helioseismic Magnetic Imager; and UV/EUV imaging from the Atmospheric

We have initiated a new survey for local extremely metal-poor galaxies (EMPGs) with Subaru/Hyper Suprime-Cam (HSC) large-area (∼500 deg 2 ) optical images reaching a 5 σ limit of ∼26 mag, about 100 times deeper than the Sloan Digital Sky Survey (SDSS). To select Z / Z ⊙ < 0.1 EMPGs from ∼40 million sources detected in the Subaru images, we first develop a machine-learning (ML) classifier based on a

While protoplanetary disks often appear to be compact and well organized in millimeter continuum emission, CO spectral line observations are increasingly revealing complex behavior at large distances from the host star. We present deep Atacama Large Millimeter/submillimeter Array maps of the J = 2−1 transition of 12 CO, 13 CO, and C 18 O, as well as the J = 3−2 transition of DCO + , toward the T Tauri

In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the absorption and emission lines decorrelated from continuum variations. During this time the soft X-ray part of the intrinsic spectrum had been strongly absorbed by a line-of-sight (LOS) obscurer, which was interpreted as the upper part of a disk wind. Our first paper

Recently, a study has shown that the Bose–Einstein condensates (BECs) formed by the d *(2380) hexaquarks ( d *(2380)-BECs) can be thermally produced in the early universe and they are stable enough to be a competitive candidate for dark matter. Searching for the decaying signature of d *(2380)-BECs is a possible way to verify this dark matter model. In this article, we discuss the scattering and decaying

The flaring activity of Sagittarius A* (Sgr A*) can be analyzed by statistical means to test emission models for its accretion flow. A particular modeling question is whether the observed X-ray flares are the high-energy end of a synchrotron spectrum or if they arise from self-Comptonized photons of a lower-energy synchrotron process. We use already published Chandra X-ray Visionary Project data to

Recently a heuristic description of collisionless perpendicular diffusion of energetic particles was presented. The latter approach describes the transport of energetic particles across a mean magnetic field based on simple physical arguments. Although this approach was developed with the intention to improve our understanding of perpendicular diffusion, this heuristic approach also provided some interesting

We present a photometric, spectroscopic, asteroseismic, and evolutionary analysis of the Algol-type eclipsing binary KIC 12268220. We find the O’Connell effect and anticorrelated eclipse timing variations in the Kepler light curve, revealing the presence of large starspots. Radial velocities and atmospheric parameters are obtained from ground-based spectroscopic observations. Combined with the radial

In the oscillation spectra of giant stars, nonradial modes may be seen to undergo avoided crossings, which produce a characteristic “mode bumping” of the otherwise uniform asymptotic p - and g -mode patterns in their respective echelle diagrams. Avoided crossings evolve very quickly relative to typical observational errors and are therefore extremely useful in determining precise ages of stars, particularly

We report the discovery of a mid-infrared (MIR) flare using Wide field Infrared Survey Explorer data in the center of the nearby Seyfert 1.9 galaxy MCG-02-04-026. The MIR flare began in the first half of 2014, peaked around the end of 2015, and faded in 2017. During these years, energy of more than 7 × 10 50 erg was released in the infrared, and the flare’s MIR color was generally turning red. We detected

The infrared Mg i lines near 12 μ m are a pair of emission lines that are magnetically sensitive and have been used to measure solar magnetic fields. Here we calculate the response of the Mg i 12.32 μ m line during a flare and find that in our modeling this line has a complicated behavior. At the beginning of the flare heating, this line shows an intensity dimming at the line center. The intensity

There is mounting evidence that the composition and structure of planetary systems are intimately linked to their birth environments. During the past decade, several spectral surveys probed the chemistry of the earliest stages of star formation and late planet-forming disks. However, very little is known about the chemistry of intermediate protostellar stages, i.e., class I young stellar objects (YSOs)

With the advent of modern neutrino and gravitational wave (GW) detectors, the promise of multimessenger detections of the next galactic core-collapse supernova (CCSN) has become very real. Such detections will give insight into the CCSN mechanism and the structure of the progenitor star, and may resolve longstanding questions in fundamental physics. In order to properly interpret these detections,

In this work, a state-of-the-art vortex detection method, Instantaneous Vorticity Deviation, is applied to locate three-dimensional vortex tube boundaries in numerical simulations of solar photospheric magnetoconvection performed by the MURaM code. We detected three-dimensional vortices distributed along intergranular regions and displaying coned shapes that extend from the photosphere to the low chromosphere

Using new ultraviolet (UV) spectra of five background quasars from the Cosmic Origins Spectrograph on the Hubble Space Telescope, we analyze the low-latitude ( ##IMG## [http://ej.iop.org/images/0004-637X/898/2/128/apjab9ff8ieqn1.gif] {$| b| =20^\circ \mbox{--}30^\circ $} ) regions of the Fermi Bubbles, the giant gamma-ray-emitting lobes at the Galactic Center. We combine these data with previous UV

Recent simulations and observations of massive galaxy cluster evolution predict that the majority of stellar mass buildup happens within cluster members by z = 2, before cluster virialization. Protoclusters rich with dusty, star-forming galaxies (DSFGs) at z > 3 are the favored candidate progenitors for these massive galaxy clusters at z ∼ 0. We present here the first study analyzing stellar emission

We present a new method to track the position and evolution of coronal loops designed for observations such as active regions in which multiple loops appear in close proximity or overlap with each other along the observational line of sight. The method is based on modeling a time–distance map containing one or more loops and fitting the modeled map to observational data, as opposed to the commonly

Global nonhydrostatic atmospheric models are becoming increasingly important for studying the climates of planets and exoplanets. However, such models suffer from computational difficulties due to the large aspect ratio between the horizontal and vertical directions. To overcome this problem, we developed a global model using a vertically implicit correction (VIC) scheme in which the integration time

We have analyzed the rotational properties of 12 clumps using 13 CO (1–0) and C 18 O (1–0) maps of the Five College Radio Astronomy Observatory 13.7 m radio telescope. The clumps, located within molecular clouds, have radii ( R ) in the range of 0.06–0.27 pc. The direction of clump elongation is not correlated with the direction of the velocity gradient. We measured the specific angular momentum (

We investigate electric current structures in Short Large-Amplitude Magnetic Structures (SLAMS) in the terrestrial ion foreshock region observed by the Magnetospheric Multiscale mission. The structures with intense currents ( ##IMG## [http://ej.iop.org/images/0004-637X/898/2/121/apjab9b8bieqn1.gif] {$| J| \sim 1\,\mu {\rm{A}}\,{{\rm{m}}}^{-2}$} ) have scale lengths comparable to the local ion inertial

A handedness in the arrival directions of high-energy photons from outside our Galaxy can be related to the helicity of an intergalactic magnetic field. Previous estimates by Tashiro et al. and Chen et al. showed a hint of a signal present in the photons observed by the Fermi Large Area Telescope (LAT). An update on the measurement of handedness in Fermi-LAT data is presented using more than 10 yr

Gas interior to the bar of the Milky Way has recently been shown to be the closest example of a low-ionization (nuclear) emission region (LI(N)ER) in the universe. To better understand the nature of this gas, a sample of face-on galaxies with integral field spectroscopy is used to study the ionized gas conditions of 240 barred and 250 nonbarred galaxies, focusing on those that are most similar to the

To accurately interpret the observed properties of exoplanets, it is necessary to first obtain a detailed understanding of host star properties. However, physical models that analyze stellar properties on a per-star basis can become computationally intractable for sufficiently large samples. Furthermore, these models are limited by the wavelength coverage of available spectra. We combine previously

We present a set of numerical simulations that model the convection zones of solar-like stars. With this suite of numerical experiments, we explore how the nature of the convective structures transitions through a series of morphological regimes as the reduced Rayleigh number increases. Convection first manifests as a belt of rotationally aligned, convective, Taylor columns that circumscribes the equator

Pulsar wind nebulae (PWNe) are the main gamma-ray emitters in the Galactic plane. They are diffuse nebulae that emit nonthermal radiation. Pulsar winds, relativistic magnetized outflows from the central star, shocked in the ambient medium produce a multiwavelength emission from the radio through gamma-rays. Although the leptonic scenario is able to explain most PWNe emission, a hadronic contribution

The breakout of a supernova blast wave from its progenitor star provides strong constraints on the star and its immediate surroundings. These surroundings are shaped by mass loss from the star and can include a wide variety of inhomogeneities. Here we present results of multidimensional radiation-hydrodynamics calculations of the interactions of the supernova blast wave with inhomogeneities in the

The possible detection of a compact object in the remnant of SN 1987A presents an unprecedented opportunity to follow its early evolution. The suspected detection stems from an excess of infrared emission from a dust blob near the compact object’s predicted position. The infrared excess could be due to the decay of isotopes like 44 Ti, accretion luminosity from a neutron star or black hole, magnetospheric

The formation of circumstellar disks is investigated using three-dimensional resistive magnetohydrodynamic simulations in which the initial prestellar cloud has a misaligned rotation axis with respect to the magnetic field. We examine the effects of (i) the initial angle difference between the global magnetic field and the cloud rotation axis ( θ 0 ) and (ii) the ratio of the thermal to gravitational

Hurricanes are one of the most extreme storm systems that occur on Earth, characterized by strong rainfall and fast winds. The terrestrial exoplanets that will be characterized with future infrared space telescopes orbit M dwarf stars. As a result, the best observable terrestrial exoplanets have vastly different climates from Earth, with a large dayside-to-nightside irradiation contrast and relatively

We present high-resolution H - and K -band spectroscopic observations of the archetypal T Tauri star T Tau North. Synthetic spectral modeling is used to derive the K -band temperature, surface gravity, magnetic field strength, and rotational velocity for this star. The K -band spectroscopic temperature measured is ##IMG## [http://ej.iop.org/images/0004-637X/898/2/109/apjab9e67ieqn1.gif] {${T}_{K \mbox{-}

Much recent work on planet formation has focused on the growth of planets by accretion of grains whose aerodynamic properties make them marginally coupled to the nebular gas, a theory commonly referred to as “pebble accretion.” While the rapid growth rates of pebble accretion can ameliorate some problems in planet formation theory, they raise new concerns as well. A particular issue is the preponderance

About half of nearby galaxies have a central surface brightness ≥1 mag below that of the sky. The overall properties of these low-surface-brightness galaxies (LSBGs) remain understudied, and in particular we know very little about their massive black hole population. This gap must be closed to determine the frequency of massive black holes at z = 0 as well as to understand their role in regulating

We report the detection of four new hot corino sources, G211.47–19.27S, G208.68–19.20N1, G210.49–19.79W, and G192.12–11.10, from a survey study of Planck Galactic Cold Clumps in the Orion Molecular Cloud Complex with the Atacama Compact Array. Three sources had been identified as low-mass Class 0 protostars in the Herschel Orion Protostar Survey. One source in the λ Orionis region is first reported

Current state-of-the-art models of the solar convection zone consist of solutions to the Navier–Stokes equations in rotating, 3D spherical shells. Such models are highly sensitive to the choice of boundary conditions. Here we present two suites of simulations differing only in their outer thermal boundary condition, which is either one of fixed entropy (FE) or fixed flux (FF; corresponding to a fixed

Regular magnetic fields are frequently found within and in the outskirts of galaxies, but their presence, properties, and origin has not yet been established for galaxy groups. On the basis of broadband radio polarimetric imaging with the Westerbork Synthesis Radio Telescope, we made use of rotation measure synthesis to disentangle contributions from magnetic fields on various scales for several polarized

We have employed a deep neural network, or deep learning , to predict the flux and the shape of the broad Ly α emission lines in the spectra of quasars. We use 17,870 high signal-to-noise ratio (S/N > 15) quasar spectra from the Sloan Digital Sky Survey Data Release 14 to train the model and evaluate its performance. The Si iv , C iv , and C iii] broad emission lines are used as the input to the neural

Parker Solar Probe (PSP) observed a large variety of Alfvénic fluctuations in the fast and slow solar wind flow during its two perihelia. The properties of Alfvénic solar wind turbulence have been studied for decades in the near-Earth environment. A spectral index of −5/3 or −2 for magnetic field fluctuations has been observed using spacecraft measurements, which can be explained by turbulence theories

We present deep (9 hr) Gemini-N/Gemini Near-InfraRed Spectrograph near-infrared spectroscopic observations of ULAS J1342+0928, a luminous quasar at z = 7.54. Various broad emission lines were detected, as well as the underlying continuum and iron forests over the rest-frame wavelength 970–2930 Å. There is a clear trend that higher-ionization emission lines show larger blueshifts with C iv ##IMG## [http://ej

In the Sun, the converting process of a poloidal magnetic field ( B pol ) from a toroidal field ( B tor ) is essential to sustaining the solar magnetic fields. However, the converting process, dominated by α and β effects, is not yet clearly understood. Conventional theories expect that the α effect should be quenched as the magnetic field grows. Also, plasma kinetic energy is thought to diffuse magnetic

Using the multi-instrument observations, we make the first simultaneous imaging and spectral study on the null point of a fan-spine magnetic topology during a solar flare. When magnetic reconnection occurs at the null point, the fan-spine configuration brightens in the (extreme-)ultraviolet channels. In the H α images, the fan-spine structure is partly filled and outlined by the bidirectional material

The integrated 21 cm H i emission profile of a galaxy encodes valuable information on the kinematics, spatial distribution, and dynamical state of its cold interstellar medium. The line width, in particular, reflects the rotation velocity of the galaxy, which, in combination with a size scale, can be used to constrain the dynamical mass of the system. We introduce a new method based on the concept

Solar flares are explosions in the solar atmosphere that release intense bursts of short-wavelength radiation and are capable of producing severe space-weather. Flares release free energy built up in coronal fields, which are rooted in active regions (ARs) on the photosphere, via magnetic reconnection. The exact processes that lead to reconnection are not fully known and therefore reliable forecasting

Drift-pair bursts are an unusual type of solar low-frequency radio emission, which appear in the dynamic spectra as two parallel drifting bright stripes separated in time. Recent imaging spectroscopy observations allowed for the quantitative characterization of the drifting pairs in terms of source size, position, and evolution. Here, the drift-pair parameters are qualitatively analyzed and compared

The detection of a high-energy muon neutrino on 2017 September 22 by the IceCube neutrino detector coincides with the multiwavelength flaring from the BL Lac object TXS 0506+056, most likely confirming an active galactic nucleus as a source of high energy cosmic rays and neutrinos. Using the photohadronic model, we have explained the very high energy γ -rays observed by MAGIC telescopes a few days

Applying the distance sum rule in strong gravitational lensing (SGL) and SN Ia observations, one can provide an interesting cosmological model-independent method to determine the cosmic curvature parameter Ω k . In this paper, with the newly compiled data sets including 161 galactic-scale SGL systems and 1048 SN Ia data, we place constraints on Ω k within the framework of three types of lens models

The gravitational wave source GW190412 is a binary black hole (BBH) merger with three unique properties: (i) its mass ratio is about 0.28, the lowest found so far, (ii) it has a relatively high positive effective spin parameter ##IMG## [http://ej.iop.org/images/0004-637X/898/2/99/apjab9b27ieqn1.gif] {${\chi }_{\mathrm{eff}}=0.25$} , and (iii) it is observed to be precessing due to in-plane projected

Stardust grains that originated in ancient stars and supernovae are recovered from meteorites and carry the detailed composition of their astronomical sites of origin. We present evidence that the majority of large ( μ m-sized) meteoritic silicon carbide (SiC) grains formed in C-rich asymptotic giant branch (AGB) stars that were more metal-rich than the Sun. In the framework of the slow neutron captures

The volatile composition of a planet is determined by the inventory of gas and ice in the parent disk. The volatile chemistry in the disk is expected to evolve over time, though this evolution is poorly constrained observationally. We present Atacama Large Millimeter/submillimeter Array observations of C 18 O, C 2 H, and the isotopologues H 13 CN, HC 15 N, and DCN toward five Class 0/I disk candidates

Direct-imaging techniques of exoplanets have made significant progress recently and will eventually enable monitoring of photometric and spectroscopic signals of Earth-like habitable planets. The presence of clouds, however, would remain as one of the most uncertain components in deciphering such direct-imaged signals of planets. We attempt to examine how the planetary obliquity produces different

The observational detection of a localized reduction in the small planet occurrence rate, sometimes termed a “gap,” is an exciting discovery because of the implications for planet evolutionary history. This gap appears to define a transition region in which sub-Neptune planets are believed to have lost their H/He envelopes, potentially by photoevaporation or core powered mass loss, and have thus been

The abundance of methyl formate (MF, HCOOCH 3 ) in star-forming regions of the interstellar medium (ISM) suggests the presence of protonated MF (H + MF). However, no spectroscopic data exist for isolated H + MF. Here, we address the vibrational properties of H + MF and its H + MF-L n ≤2 clusters (L = Ar/N 2 ) by infrared photodissociation (IRPD) spectroscopy and density functional theory calculations