Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>We present a catalog of central engine properties, i.e., black hole mass (<jats:italic>M</jats:italic> <jats:sub>BH</jats:sub>) and accretion luminosity (<jats:italic>L</jats:italic> <jats:sub>disk</jats:sub>), for a sample of 1077 blazars detected with the Fermi Large Area Telescope. This includes broad emission-line systems and blazars whose optical spectra lack emission lines but are dominated by the absorption features arising from the host galaxy. The average <jats:italic>M</jats:italic> <jats:sub>BH</jats:sub> for the sample is <jats:inline-formula> <jats:tex-math> <?CDATA $\langle \mathrm{log}\,{M}_{\mathrm{BH},\mathrm{all}{M}_{\odot }}\rangle =8.60$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsabe135ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, and there is evidence suggesting the association of more massive black holes with absorption-line systems. Our results indicate a bimodality of <jats:italic>L</jats:italic> <jats:sub>disk</jats:sub> in Eddington units (<jats:italic>L</jats:italic> <jats:sub>disk</jats:sub>/<jats:italic>L</jats:italic> <jats:sub>Edd</jats:sub>) with broad-line objects tend to have a higher accretion rate (<jats:italic>L</jats:italic> <jats:sub>disk</jats:sub>/<jats:italic>L</jats:italic> <jats:sub>Edd</jats:sub> &gt; 0.01). We have found that <jats:italic>L</jats:italic> <jats:sub>disk</jats:sub>/<jats:italic>L</jats:italic> <jats:sub>Edd</jats:sub> and Compton dominance (CD; the ratio of the inverse Compton to synchrotron peak luminosities) are positively correlated at the &gt;5<jats:italic>σ</jats:italic> confidence level, suggesting that the latter can be used to reveal the state of accretion in blazars. Based on this result, we propose a CD-based classification scheme. Sources with CD &gt; 1 can be classified as high-Compton-dominated or HCD blazars, whereas those with CD ≲ 1 are low-Compton-dominated (LCD) objects. This scheme is analogous to that based on the mass accretion rate proposed in the literature; however, it overcomes the limitation imposed by the difficulty in measuring <jats:italic>L</jats:italic> <jats:sub>disk</jats:sub> and <jats:italic>M</jats:italic> <jats:sub>BH</jats:sub> for objects with quasi-featureless spectra. We conclude that the overall physical properties of Fermi blazars are likely to be controlled by the accretion rate in Eddington units. The catalog is made public at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.ucm.es/blazars/engines" xlink:type="simple">http://www.ucm.es/blazars/engines</jats:ext-link> and Zenodo.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Normal-mode helioseismic data analysis uses observed solar oscillation spectra to infer perturbations in the solar interior due to global and local-scale flows and structural asphericity. Differential rotation, the dominant global-scale axisymmetric perturbation, has been tightly constrained primarily using measurements of frequency splittings via “<jats:italic>a</jats:italic>-coefficients.” However, the frequency-splitting formalism invokes the approximation that multiplets are isolated. This assumption is inaccurate for modes at high angular degrees. Analyzing eigenfunction corrections, which respect cross-coupling of modes across multiplets, is a more accurate approach. However, applying standard inversion techniques using these cross-spectral measurements yields <jats:italic>a</jats:italic>-coefficients with a significantly wider spread than the well-constrained results from frequency splittings. In this study, we apply Bayesian statistics to infer <jats:italic>a</jats:italic>-coefficients due to differential rotation from cross-spectra for both <jats:italic>f</jats:italic>-modes and <jats:italic>p</jats:italic>-modes. We demonstrate that this technique works reasonably well for modes with angular degrees <jats:italic>ℓ</jats:italic> = 50–291. The inferred <jats:italic>a</jats:italic> <jats:sub>3</jats:sub>-coefficients are found to be within 1 nHz of the frequency-splitting values for <jats:italic>ℓ</jats:italic> &gt; 200. We also show that the technique fails at <jats:italic>ℓ</jats:italic> &lt; 50 owing to the insensitivity of the measurement to the perturbation. These results serve to further establish mode-coupling as an important helioseismic technique with which to infer internal structure and dynamics, both axisymmetric (e.g., meridional circulation) and non-axisymmetric perturbations.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Faraday rotation provides a valuable tracer of magnetic fields in the interstellar medium; catalogs of Faraday rotation measures provide key observations for studies of the Galactic magnetic field. We present a new catalog of rotation measures derived from the Canadian Galactic Plane Survey, covering a large region of the Galactic plane spanning 52° &lt; <jats:italic>l</jats:italic> &lt; 192°, −3° &lt; <jats:italic>b</jats:italic> &lt; 5°, along with northern and southern latitude extensions around <jats:italic>l</jats:italic> ≈ 105°. We have derived rotation measures for 2234 sources (4 of which are known pulsars), 75% of which have no previous measurements, over an area of approximately 1300 deg<jats:sup>2</jats:sup>. These new rotation measures increase the measurement density for this region of the Galactic plane by a factor of 2.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We describe a new algorithm to implicitly solve the time-dependent, frequency-integrated radiation transport (RT) equation, which is coupled to an explicit solver for equations of magnetohydrodynamics (MHD) using <jats:sans-serif>Athena++</jats:sans-serif>. The radiation field is represented by specific intensities along discrete rays, which are evolved using a conservative finite volume approach for both Cartesian and curvilinear coordinate systems. All terms for spatial transport of photons and interactions between gas and radiation are calculated implicitly together. An efficient Jacobi-like iteration scheme is used to solve the implicit equations. This removes any time-step constraint due to the speed of light in RT. We evolve the specific intensities in the lab frame to simplify the transport step. The lab frame specific intensities are transformed to the comoving frame via Lorentz transformation when the source term is calculated. Therefore, the scheme does not need any expansion in terms of <jats:italic>v</jats:italic>/<jats:italic>c</jats:italic>. The radiation energy and momentum source terms for the gas are calculated via direct quadrature in the angular space. The time step for the whole scheme is determined by the normal Courant–Friedrichs–Lewy condition in the MHD module. We provide a variety of test problems for this algorithm, including both optically thick and thin regimes, and for both gas and radiation pressure-dominated flows to demonstrate its accuracy and efficiency.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We demonstrate the potential of an emulator-based approach to analyzing galaxy formation models in the domain where constraining data is limited. We have applied the open-source P<jats:sc>ython</jats:sc> package P<jats:sc>rism</jats:sc> to the galaxy formation model M<jats:sc>eraxes</jats:sc>. M<jats:sc>eraxes</jats:sc> is a semianalytic model, purposely built to study the growth of galaxies during the Epoch of Reionization. Constraining such models is however complicated by the scarcity of observational data in the EoR. P<jats:sc>rism</jats:sc>’s ability to rapidly construct accurate approximations of complex scientific models using minimal data is therefore key to performing this analysis well. This paper provides an overview of our analysis of M<jats:sc>eraxes</jats:sc> using measurements of galaxy stellar mass densities, luminosity functions, and color–magnitude relations. We demonstrate the power of using P<jats:sc>rism</jats:sc> instead of a full Bayesian analysis when dealing with highly correlated model parameters <jats:italic>and</jats:italic> a scarce set of observational data. Our results show that the various observational data sets constrain M<jats:sc>eraxes</jats:sc> differently and do not necessarily agree with each other, signifying the importance of using multiple observational data types when constraining such models. Furthermore, we show that P<jats:sc>rism</jats:sc> can detect when model parameters are too correlated or cannot be constrained effectively. We conclude that a mixture of different observational data types, even when they are scarce or inaccurate, is a priority for understanding galaxy formation and that emulation frameworks such as P<jats:sc>rism</jats:sc> can guide the selection of such data.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a catalog of 75,867 periodic variable stars from data release 7 of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope. We calculated the chromospheric activity index, equivalent widths for 201,349 spectra, and excess fractional luminosity (<jats:inline-formula> <jats:tex-math> <?CDATA ${R}_{{\rm{H}}\alpha }^{{\prime} }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> <mml:mi>α</mml:mi> </mml:mrow> <mml:mrow> <mml:mo accent="true">′</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsabe30bieqn1.gif" xlink:type="simple" /> </jats:inline-formula>) for 130,796 spectra. Based on the intensity of the H<jats:italic>α</jats:italic> line, we detected 30,719 F-, G-, and K-type variable stars with H<jats:italic>α</jats:italic> fill-in or emission and 2521 M-type variable stars exhibiting H<jats:italic>α</jats:italic> emission. Furthermore, 14,938 out of 30,573 periodic variable stars showed H<jats:italic>α</jats:italic> variability. Analysis of samples with different spectral types confirmed that the activity fraction of stars with later spectral type clearly decreases as the absolute Galactic height increases away from the Galactic plane. The results also show that at the same absolute Galactic height, the activity fractions in eclipsing binaries are higher than those in single stars. In this study, we present the activity–rotation relations for F-, G-, K-, and M-type variable stars. The results of analysis show that rapid rotators keep a saturated value, and the absolute value of the power-law index exhibits an increasing trend from F- to K-type stars in the unsaturated regime. Moreover, we confirm that the angular momentum and magnetic momentum are positively correlated, which indicates that the <jats:italic>α</jats:italic>–<jats:italic>ω</jats:italic> dynamo may be working. In addition, we confirmed the correlations among the H<jats:italic>α</jats:italic>, H<jats:italic>β</jats:italic>, H<jats:italic>γ</jats:italic>, H<jats:italic>δ</jats:italic>, Ca <jats:sc>ii</jats:sc> H&amp;K, and Ca <jats:sc>ii</jats:sc> infrared triplet lines.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Neutrino–matter interactions play an important role in core-collapse supernova (CCSN) explosions, as they contribute to both lepton number and/or four-momentum exchange between neutrinos and matter and thus act as the agent for neutrino-driven explosions. Due to the multiscale nature of neutrino transport in CCSN simulations, an implicit treatment of neutrino–matter interactions is desired, which requires solutions of coupled nonlinear systems in each step of the time integration scheme. In this paper, we design and compare nonlinear iterative solvers for implicit systems with energy-coupling neutrino–matter interactions commonly used in CCSN simulations. Specifically, we consider electron neutrinos and antineutrinos, which interact with static matter configurations through the Bruenn 85 opacity set. The implicit systems arise from the discretization of a nonrelativistic two-moment model for neutrino transport, which employs the discontinuous Galerkin (DG) method for phase-space discretization and an implicit–explicit (IMEX) time integration scheme. In the context of this DG-IMEX scheme, we propose two approaches to formulate the nonlinear systems: a coupled approach and a nested approach. For each approach, the resulting systems are solved with Anderson-accelerated fixed-point iteration and Newton’s method. The performance of these four iterative solvers has been compared on relaxation problems with various degrees of collisionality, as well as proto–neutron star deleptonization problems with several matter profiles adopted from spherically symmetric CCSN simulations. Numerical results suggest that the nested Anderson-accelerated fixed-point solver is more efficient than other tested solvers for solving implicit nonlinear systems with energy-coupling neutrino–matter interactions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present panchromatic resolved stellar photometry for 22 million stars in the Local Group dwarf spiral Triangulum (M33), derived from Hubble Space Telescope observations with the Advanced Camera for Surveys in the optical (F475W, F814W), and the Wide Field Camera 3 in the near-ultraviolet (F275W, F336W) and near-infrared (F110W, F160W) bands. The large, contiguous survey area covers ∼14 square kpc and extends to 3.5 kpc (14′, or 1.5–2 scale lengths) from the center of M33. The PHATTER observing strategy and photometry technique closely mimics that of Panchromatic Hubble Andromeda Treasury, but with updated photometry techniques that take full advantage of all overlapping pointings (aligned to within &lt;5–10 milliarcseconds) and improved treatment of spatially varying point-spread functions. The photometry reaches a completeness-limited depth of F475W∼28.5 in the lowest surface density regions observed in M33 and F475W∼26.5 in the most crowded regions found near the center of M33. We find the young populations trace several relatively tight arms, while the old populations show a clear, looser two-armed structure. We present extensive analysis of the data quality, including artificial star tests to quantify completeness, photometric uncertainties, and flux biases. This stellar catalog is the largest ever produced for M33, and is publicly available for download by the community.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>This paper reports 209 O-type stars found with LAMOST. All 135 new O-type stars discovered so far with LAMOST are given. Among them, 94 stars are first presented in this sample. There are 1 Iafpe star, 5 Onfp stars, 12 Oe stars, 1 Ofc stars, 3 ON stars, 16 double-lined spectroscopic binaries, and 33 single-lined spectroscopic binaries. All O-type stars are determined based on LAMOST low-resolution spectra (<jats:italic>R</jats:italic> ∼ 1800), with their LAMOST median-resolution spectra (<jats:italic>R</jats:italic> ∼ 7500) as supplements.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this paper, an implicit nonsymplectic exact energy-preserving integrator is specifically designed for a ten-dimensional phase-space conservative Hamiltonian system with five degrees of freedom. It is based on a suitable discretization-averaging of the Hamiltonian gradient, with a second-order accuracy to numerical solutions. A one-dimensional disordered discrete nonlinear Schrödinger equation and a post-Newtonian Hamiltonian system of spinning compact binaries are taken as our two examples. We demonstrate numerically that the proposed algorithm exhibits good long-term performance in the preservation of energy, if roundoff errors are neglected. This result is independent of time steps, initial orbital eccentricities, and regular and chaotic orbital dynamical behavior. In particular, the application of appropriately large time steps to the new algorithm is helpful in reducing time-consuming and roundoff errors. This new method, combined with fast Lyapunov indicators, is well suited to studying the influence of some parameters or initial conditions related to chaos in the two example problems. It is found that chaos in the former system is mainly responsible for one of the parameters. In the latter problem, a combination of small initial separations and high initial eccentricities can easily induce chaos.</jats:p>