adsabs/SciX_UAT_keywords huggingface dataset:
Optical and Infrared Counterparts of the X-Ray Sources Detected in the Chandra Cygnus OB2 Legacy Survey

The young massive OB association Cygnus OB2, in the Cygnus X complex, is the closest (~1400 pc) star-forming region to the Sun hosting thousands of young low-mass stars and up to 1000 OB stars, among which are some of the most massive stars known in our Galaxy. This region holds great importance for several fields of modern astrophysics, such as the study of the physical properties of massive and young low-mass stars and the feedback provided by massive stars on star and planet formation processes. Cyg OB2 has been recently observed with Chandra/ACIS-I as part of the 1.08 Ms Chandra Cygnus OB2 Legacy Project. This survey detected 7924 X-ray sources in a square degree area centered on Cyg OB2. Since a proper classification and study of the observed X-ray sources also requires the analysis of their optical and infrared counterparts, we combined a large and deep set of optical and infrared catalogs available for this region with our new X-ray catalog. In this paper we describe the matching procedure and present the combined catalog containing 5703 sources. We also briefly discuss the nature of the X-ray sources with optical and infrared counterparts using their position in the color-magnitude and color-color diagrams.

Keywords: astronomy databases; catalogs
Coproduction of Light and Heavy r-process Elements via Fission Deposition

We apply for the first time fission yields determined across the chart of nuclides from the macroscopic-microscopic theory of the Finite Range Liquid Drop Model to simulations of rapid neutron capture (r-process) nucleosynthesis. With the fission rates and yields derived within the same theoretical framework utilized for other relevant nuclear data, our results represent an important step toward self-consistent applications of macroscopic-microscopic models in r-process calculations. The yields from this model are wide for nuclei with extreme neutron excess. We show that these wide distributions of neutron-rich nuclei, and particularly the asymmetric yields for key species that fission at late times in the r process, can contribute significantly to the abundances of the lighter heavy elements, specifically the light precious metals palladium and silver. Since these asymmetric yields correspondingly also deposit into the lanthanide region, we consider the possible evidence for coproduction by comparing our nucleosynthesis results directly with the trends in the elemental ratios of metal-poor stars rich in r-process material. We show that for r-process enhanced stars palladium over europium and silver over europium display mostly flat trends suggestive of coproduction and compare to the lanthanum over europium trend which is often used to justify robustness arguments in the lanthanide region. We find that such robustness arguments may be extendable down to palladium and heavier and demonstrate that fission deposition is a mechanism by which such a universality or robustness can be achieved.

Keywords: nucleosynthesis; stellar abundances; nuclear astrophysics; neutron stars
The Solar Wind Interaction with (1) Ceres: The Role of Interior Conductivity

As a potential "ocean world," (1) Ceres' interior may possess relatively high electrical conductivities on the order of 10-4-100 S m-1, suggesting that the solar wind interaction with Ceres may differ from other highly resistive objects such as the Moon. Here, we use a hybrid plasma model to quantify the solar wind interaction with Ceres over a range of scenarios for Ceres' internal conductivity structure and the upstream solar wind and interplanetary magnetic field (IMF) conditions. Internal models for Ceres include one-, two-, and three-layer conductivity structures that variously include a crust, mantle, and/or subsurface ocean, while modeled solar wind conditions include a nominal case, a high IMF case, and an "extreme" space weather case. To first order, Ceres' interaction with the solar wind is governed by the draping and enhancement of the IMF over its interior, whether from a moderate-conductivity mantle or a high-conductivity ocean. In turn, IMF draping induces compressional wings in the solar wind density and deceleration in the solar wind speed outside of Ceres. Together, all three effects are readily observable by a hypothetical orbital or landed mission with standard plasma and magnetic field instrumentation. Finally, we also consider the possible effects of unipolar induction within Ceres, which has been previously suggested as a mechanism for conducting bodies in the solar wind. Our model results show that the efficacy of unipolar induction is highly suppressed by the slow magnetic field-line diffusion through Ceres' interior and, thus, is not a significant contributor to Ceres' overall interaction with the solar wind.

Keywords: ceres; planetary interior; solar wind; interplanetary magnetic fields
A Simple Method to Estimate the Refractive Index Structure Parameter ( {C}_{n}(2) ) in the Atmosphere

This paper proposes a simple physics-based method for estimating the ${C}_{n}^{2}$ profile in the lower atmosphere, using the Ellison scale as a measure of the outer turbulence scale. The new approach only Requires the temperature profile as an input to obtain the profile of the outer turbulence scale, followed by the ${C}_{n}^{2}$ profile. Using sounding data from Lhasa (Tibet) ${C}_{n}^{2}$ profiles were estimated using three outer scale models (Thorpe, HMNSP99, and Ellison) and compared with the measured ${C}_{n}^{2}$ profile. Results show that the Ellison scale method offers better results as a profile estimator than the other two methods. Compared with the measured ${C}_{n}^{2}$ profile, the average relative error of the Ellison scale method is generally lower than 8%, with a correlation coefficient larger than 0.5.

Keywords: atmospheric effects; atmospheric refraction
Tracking Movement of Long-lived Equatorial Coronal Holes from Analysis of Long-term McIntosh Archive Data

Features at the Sun's surface and atmosphere are constantly changing due to its magnetic field. The McIntosh Archive provides a long-term (45 yr) record of these features, digitized from hand-drawn synoptic maps by Patrick McIntosh. Utilizing this data, we create stack plots for coronal holes, i.e., Hovmöller-type plots of latitude bands, for all longitudes, stacked in time, allowing tracking of coronal hole movement. Using a newly developed two-step method of centroid calculation, which includes a Fourier descriptor to represent a coronal hole's boundary and calculate the centroid by the use of Green's theorem, we calculate the centroids of 31 unique, long-lived equatorial coronal holes for successive Carrington rotations during the entire solar cycle 23, and estimate their slopes (time versus longitude) as the coronal holes evolve. We compute coronal hole centroid drift speeds from these slopes, and find an eastward (prograde) pattern that is actually retrograde with respect to the local differential rotation. By discussing the plausible physical mechanisms which could cause these long-lived equatorial coronal holes to drift retrograde, we identify either classical or magnetically modified westward-propagating solar Rossby waves, with a speed of a few tens to a few hundreds of meters per second, to be the best candidate for governing the drift of deep-rooted, long-lived equatorial coronal holes. To explore plausible physics of why long-lived equatorial coronal holes appear few in number during solar minimum/early rising phase more statistics are required, which will be studied in future.

Keywords: solar coronal holes; solar cycle; solar motion
A Distance-deviation Consistency and Model-independent Method to Test the Cosmic Distance-Duality Relation

A distance-deviation consistency and model-independent method to test the cosmic distance-duality relation (CDDR) is provided. This method is worthy of attention for two reasons. First, a distance-deviation consistency method is used to pair subsamples: instead of pairing subsamples with redshift deviations smaller than a value of, say, $\left|{\rm{\Delta }}z\right|\lt 0.005$ . The redshift deviation between subsamples decreases with the redshift to ensure the distance deviation stays the same. The method selects more subsamples at high redshift, up to z = 2.16, and provides 120 subsample pairs. Second, the model-independent method involves the latest data set of 1048 SNe Ia and 205 strong gravitational lensing systems (SGLS), which are used to obtain the luminosity distances DL and the ratio of angular diameter distance DA, respectively. With the model-independent method, parameters of the CDDR, the SNe Ia light curve, and the SGLS are fitted simultaneously. The result shows that $\eta ={0.047}_{-0.151}^{+0.190}$ and CDDR is validated at the 1σ confidence level in the form of $\tfrac{{D}_{L}}{{D}_{A}}{\left(1+z\right)}^{-2}=1+\eta z$ .

Keywords: cosmology
MAGAZ3NE: High Stellar Velocity Dispersions for Ultramassive Quiescent Galaxies at z ≳ 3

In this work, we publish stellar velocity dispersions, sizes, and dynamical masses for eight ultramassive galaxies (UMGs; $\mathrm{log}({M}_{* }/{M}_{\odot })$ > 11), z ≳ 3) from the Massive Ancient Galaxies At z > 3 NEar-infrared (MAGAZ3NE) Survey, more than doubling the number of such galaxies with velocity dispersion measurements at this epoch. Using the deep Keck/MOSFIRE and Keck/NIRES spectroscopy of these objects in the H and K bandpasses, we obtain large velocity dispersions of ~400 km s-1 for most of the objects, which are some of the highest stellar velocity dispersions measured and ~40% larger than those measured for galaxies of similar mass at z ~ 1.7. The sizes of these objects are also smaller by a factor of 1.5-3 compared to this same z ~ 1.7 sample. We combine these large velocity dispersions and small sizes to obtain dynamical masses. The dynamical masses are similar to the stellar masses of these galaxies, consistent with a Chabrier initial mass function (IMF). Considered alongside previous studies of massive quiescent galaxies across 0.2 < z < 4.0, there is evidence for an evolution in the relation between the dynamical mass-stellar mass ratio and velocity dispersion as a function of redshift. This implies an IMF with fewer low-mass stars (e.g., Chabrier IMF) for massive quiescent galaxies at higher redshifts in conflict with the bottom-heavy IMF (e.g., Salpeter IMF) found in their likely z ~ 0 descendants, though a number of alternative explanations such as a different dynamical structure or significant rotation are not ruled out. Similar to data at lower redshifts, we see evidence for an increase of IMF normalization with velocity dispersion, though the z ≳ 3 trend is steeper than that for z ~ 0.2 early-type galaxies and offset to lower dynamical-to-stellar mass ratios. * The spectra presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Keywords: galaxy evolution; high-redshift galaxies; quenched galaxies
Updated Parameters and a New Transmission Spectrum of HD 97658b

Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD 97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Telescope transits, 12 Spitzer/IRAC transits, and eight MOST transits of this system. Our transmission spectrum has a higher signal-to-noise ratio than those from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1-1.7 μm reported in previous works on the transmission spectrum of this planet is likely systematic. Nonetheless, our atmospheric modeling results are inconclusive, as no model provides an excellent match to our data. Nonetheless, we find that atmospheres with high C/O ratios (C/O ≳ 0.8) and metallicities of ≳100× solar metallicity are favored. We combine the mid-transit times from all of the new Spitzer and MOST observations and obtain an updated orbital period of P = 9.489295 ± 0.000005, with a best-fit transit time center at T0 = 2456361.80690 ± 0.00038 (BJD). No transit timing variations are found in this system. We also present new measurements of the stellar rotation period (34 ± 2 days) and stellar activity cycle (9.6 yr) of the host star HD 97658. Finally, we calculate and rank the Transmission Spectroscopy Metric of all confirmed planets cooler than 1000 K and with sizes between 1 R⊕ and 4 R⊕. We find that at least a third of small planets cooler than 1000 K can be well characterized using James Webb Space Telescope, and of those, HD 97658b is ranked fifth, meaning that it remains a high-priority target for atmospheric characterization.

Keywords: transit photometry; hubble space telescope; exoplanet atmospheres; radial velocity
Photometry of Optical Outbursts in the Be/X-Ray Binary Swift J010745.0-722740

We present V and I photometry for the Be/X-ray binary Swift J010745.0-722740 taken in 1997-2020. The data show recurring outbursts, with an amplitude up to 0.4 mag and an improved orbital period of 1180.0 ± 0.3 days. The light curve during outburst has a double-peaked profile, with a rapid rise and gradual decline. The effective temperature of the outburst region is ∼6200 K, much cooler than that of an underlying Be star.

Keywords: be stars; high mass x-ray binary stars
Rotating Vector Model and Radius-to-frequency Mapping in the Presence of a Multipole Magnetic Field

The rotating vector model and radius-to-frequency mapping in the presence of a multipole magnetic field in pulsars and magnetars are considered. An axisymmetric potential field is assumed, and the following is found: (1) The radiation beam in the case of a multipole field is wider than the dipole case. This may account for the increasing pulse width at the higher frequency of pulsars (anti-radius-to-frequency mapping); (2) The expression for the polarization position angle is unchanged. Only the inclination angle α and phase constant ϕ 0 will change. The angle between the rotational axis and line of sight and the position angle constant ψ 0 will not change. When fitting the varying position angle of magnetars, these constraints should be considered. The appearance and disappearance of a multipole field may account for the changing slope of the position angle in the radio-emitting magnetar Swift J1818.0-1607. A similar but more active process in magnetar magnetospheres may account for the diverse position angle in fast radio bursts.

Keywords: neutron stars; pulsars; magnetars
Effects of Spin on Constraining the Seeds and Growth of ≳109M⊙ Supermassive Black Holes in z > 6.5 Quasars

The existence of ≳109M⊙ supermassive black holes (SMBHs) at redshift z > 6 raises the problem of how such SMBHs can grow up within the cosmic time (<1 Gyr) from small seed BHs. In this Letter, we use the observations of 14 quasars at z > 6.5 with mass estimates to constrain their seeds and early growth, by self-consistently considering the spin evolution and the possibility of super-Eddington accretion. We find that spin plays an important role in the growth of early SMBHs, and the constraints on seed mass and super-Eddington accretion fraction strongly depend on the assumed accretion history. If the accretion is coherent with single (or a small number of) episode(s), leading to high spins for the majority of accretion time, then the SMBH growth is relatively slow; and if the accretion is chaotic with many episodes and in each episode the total accreted mass is much less than the SMBH mass, leading to moderate/low spins, then the growth is relatively fast. The constraints on the seed mass and super-Eddington accretion fraction are degenerate. A significant fraction (≳0.1%-1% in linear scale but ∼3-4 dex in logarithmic scale for 103-104M⊙ seeds) of super-Eddington accretion is required if the seed mass is not ≫105M⊙, and the requirements of high seed mass and/or super-Eddington accretion fraction are moderately relaxed if the accretion is chaotic.

Keywords: accretion; black hole physics; early universe; galaxy nuclei; quasars; supermassive black holes
Rotation Optimized Filter for Longevity (ROFL): Increasing the Lifetime of Swift/UVOT Simply

I demonstrate that a very simple and safe change to the planning software filter assignment algorithm for the Ultraviolet/Optical Telescope (UVOT) onboard the Neil Gehrels Swift Observatory can reduce the number of filter wheel rotations by >10%, and its adoption is thus likely to significantly extend the usable lifetime of the UVOT instrument.

Keywords: ultraviolet telescopes
Impact of a Magnetic Field on Neutrino-Matter Interactions in Core-collapse Supernovae

We explore the impact of a magnetic field on neutrino-matter interactions in core-collapse supernovae. We first derive the modified source terms for neutrino-nucleon scattering and neutrino absorption and emission processes in the moment formalism. Then, we perform full relativistic, three-dimensional, magnetorotational core-collapse supernova simulations of a $20\,{M}_{\odot }$ star with spectral neutrino transport. Our simulations self-consistently treat the parity-violation effects of weak interaction in the presence of an external magnetic field. The result shows significant global asymmetry, mostly confined in the proto-neutron star, clearly reflecting the magnetic field structure. The asymmetric property arises from two factors: the angle between the neutrino flux and magnetic field, and the term that is parallel to the magnetic field and is also proportional to the deviation of the distribution function of neutrinos from thermal equilibrium. The typical correction value amounts to ∼1% relative to the total neutrino-matter interaction rate for the magnetic field strength of $\sim {10}^{15\mbox{--}16}$ G. Although these asymmetric properties do not immediately affect the explosion dynamics, our results imply that they would be significant once the neutrinos diffuse out of the proto-neutron- star core carrying those asymmetries away. We also show that, during our simulation time of ∼370 ms after bounce, our results indicate that the correction value due to the modified inelastic scattering process dominates over that of the modified neutrino absorption and emission process.

Keywords: core-collapse supernovae; magnetohydrodynamical simulations; supernova neutrinos; supernova dynamics; radiative magnetohydrodynamics
Detection of the Extended γ-Ray Emission around Supernova Remnant DA 530 with Fermi-LAT

We report the extended GeV γ-ray emission around the high Galactic latitude supernova remnant DA 530 with the PASS 8 data recorded by the Fermi Large Area Telescope. The γ-ray spectrum in the energy range of 100 MeV-1 TeV follows a power-law model with an index of 2.23. The γ-ray emission, which is much more extended than the radio shell of DA 530, and the spatial coincidence with the molecular cloud suggest that the γ-ray emission could be originated from the hadronic process, where the high-energy protons accelerated in and escaped from the shock of DA 530. With a steady-state injection model of protons, the γ-ray spectrum can be well fitted with the typical Galactic value for the diffusion coefficient and the low-energy content of the total escaped protons.

Keywords: supernova remnants; gamma-rays; gamma-ray sources; molecular clouds
Hot Dust-obscured Galaxies with Excess Blue Light

Hot dust-obscured galaxies (Hot DOGs) are among the most luminous galaxies in the universe. Powered by highly obscured, possibly Compton-thick, active galactic nuclei (AGNs), Hot DOGs are characterized by spectral energy distributions that are very red in the mid-infrared yet dominated by the host galaxy stellar emission in the UV and optical. An earlier study identified a subsample of Hot DOGs with significantly enhanced UV emission. One target, W0204-0506, was studied in detail and, based on Chandra observations, it was concluded that the enhanced emission was most likely due to either extreme unobscured star formation (star formation rate > 1000 M⊙ yr-1) or to light from the highly obscured AGN scattered by gas or dust into our line of sight. Here, we present a follow-up study of W0204-0506 as well as two more Hot DOGs with excess UV emission. For the two new objects we obtained Chandra/ACIS-S observations, and for all three targets we obtained Hubble Space Telescope/WFC3 F555W and F160W imaging. The analysis of these observations, combined with multiwavelength photometry and UV/optical spectroscopy suggests that UV emission is most likely dominated by light from the central highly obscured, hyperluminous AGN that has been scattered into our line of sight, by either gas or dust. We cannot decisively rule out, however, that star formation or a second AGN in the system may significantly contribute to the UV excess of these targets.

Keywords: high-redshift galaxies; active galaxies; galaxy evolution; infrared galaxies; quasars
Low Star Formation Activity and Low Gas Content of Quiescent Galaxies at z = 3.5-4.0 Constrained with ALMA

The discovery in deep near-infrared surveys of a population of massive quiescent galaxies at z > 3 has given rise to the question of how they came to be quenched so early in the history of the universe. Measuring their molecular gas properties can distinguish between physical processes where they stop forming stars due to a lack of fuel versus those where the star formation efficiency is reduced and the gas is retained. We conducted Atacama Large Millimeter/submillimeter Array observations of four quiescent galaxies at z = 3.5-4.0 found by the Fourstar Galaxy Evolution Survey and a serendipitous optically dark galaxy at z = 3.71. We aim to investigate the presence of dust-obscured star formation and their gas content by observing the dust continuum emission at Band 7 and the atomic carbon [C I](3 P 1-3 P 0) line at 492.16 GHz. Among the four quiescent galaxies, only one source is detected in the dust continuum at λ obs = 870 μm. The submillimeter observations confirm their passive nature, and all of them are located more than four times below the main sequence of star-forming galaxies at z = 3.7. None of the targets are detected in [C I], constraining their gas-mass fractions to be <20%. These gas-mass fractions are more than 3 times lower than the scaling relation for star-forming galaxies at z = 3.7. These results support scenarios where massive galaxies at z = 3.5-4.0 quench by consuming/expelling all the gas rather than by reducing the efficiency of the conversion of their gas into stars.

Keywords: galaxy evolution; high-redshift galaxies; quenched galaxies; submillimeter astronomy