Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>In this work, we expand upon the Tomographic Absorption Reconstruction and Density Inference Scheme (TARDIS) in order to include multiple tracers while reconstructing matter density fields at Cosmic Noon (<jats:italic>z</jats:italic> ∼ 2–3). In particular, we jointly reconstruct the underlying density field from simulated Ly<jats:italic>α</jats:italic> forest observations at <jats:italic>z</jats:italic> ∼ 2.5 and an overlapping galaxy survey. We find that these data are synergistic, with the Ly<jats:italic>α</jats:italic> forest providing reconstruction of low-density regions and galaxy surveys tracing the density peaks. We find a more accurate power spectra reconstruction going to higher scales when fitting these two data sets simultaneously than when using either one individually. When applied to cosmic web analysis, we find that performing the joint analysis is equivalent to an Ly<jats:italic>α</jats:italic> survey with significantly increased sight-line spacing. Because we reconstruct the velocity field and matter field jointly, we demonstrate the ability to evolve the mock observed volume further to <jats:italic>z</jats:italic> = 0, allowing us to create a rigorous definition of a “protocluster” as regions that will evolve into clusters. We apply our reconstructions to study protocluster structure and evolution, finding for realistic survey parameters that we can provide accurate mass estimates of the <jats:italic>z</jats:italic> ≈ 2 structures and their <jats:italic>z</jats:italic> = 0 fate.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The detection of gravitational waves (GWs) from a binary neutron star (BNS) has opened a new window on gravitational wave astronomy. With current sensitivities, detectable signals coming from compact objects like neutron stars turn out to be a crucial ingredient for probing their structure, composition, and evolution. Moreover, astronomical observations on pulsars and their mass–radius relations place important constraints on the dense matter equation of state. In this paper, we consider a homogeneous and unpaired charge-neutral three-flavor interacting quark matter with <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal O }({m}_{s}^{4})$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabc87fieqn1.gif" xlink:type="simple" /> </jats:inline-formula> corrections that account for the moderately heavy strange quark instead of the naive MIT bag model. We perform a detailed analysis of strange quark stars in the context of the recently proposed 4D Einstein–Gauss–Bonnet (EGB) theory of gravity. However, this theory does not have standard 4D equations. Thus, we show that the equivalence of the actions in the regularized 4D EGB theory and in the original one is satisfied for a spherically symmetric spacetime. We pay particular attention to the possible existence of neutron stars of mass compatible with <jats:inline-formula> <jats:tex-math> <?CDATA $M\sim 2{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabc87fieqn2.gif" xlink:type="simple" /> </jats:inline-formula>. Our findings suggest that the fourth-order correction parameter (<jats:italic>a</jats:italic> <jats:sub>4</jats:sub>) of the quantum chromodynamic perturbation and coupling constant <jats:italic>α</jats:italic> of the GB term play an important role in the mass–radius relation as well as the stability of the quark star. Finally, we compare the results with the well-measured limits of pulsars and their mass and radius extracted from the spectra of several X-ray compact sources.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The alignment of dust grains with the ambient magnetic field produces polarization of starlight as well as thermal dust emission. Using the archival SOFIA/HAWC+ polarimetric data observed toward the <jats:italic>ρ</jats:italic> Ophiuchus (Oph) A cloud hosted by a B star at 89 and 154 <jats:italic>μ</jats:italic>m, we find that the fractional polarization of thermal dust emission first increases with the grain temperature and then decreases once the grain temperature exceeds ≃25–32 K. The latter trend differs from the prediction of the popular RAdiative Torques (RATs) alignment theory, which implies a monotonic increase of the polarization fraction with the grain temperature. We perform numerical modeling of polarized dust emission for the <jats:italic>ρ</jats:italic> Oph-A cloud and calculate the degree of dust polarization by simultaneously considering the dust grain alignment and rotational disruption by RATs. Our modeling results could successfully reproduce both the rising and declining trends of the observational data. Moreover, we show that the alignment of only silicate grains or a mixture of silicate–carbon grains within a composite structure can reproduce the observational trends, assuming that all dust grains follow a power-law size distribution. Although there are a number of simplifications and limitations to our modeling, our results suggest grains in the <jats:italic>ρ</jats:italic> Oph-A cloud have a composite structure, and the grain size distribution has a steeper slope than the standard size distribution for the interstellar medium. Combination of SOFIA/HAWC+ data with JCMT observations 450 and 850 <jats:italic>μ</jats:italic>m would be useful to test the proposed scenario based on grain alignment and disruption by RATs.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>A primordial magnetic field with strength in the 1–10 pG range can resolve the tension between different measurements of the Hubble constant and provide an explanation for the excess opacity in the 21 cm line at redshift 15 &lt; <jats:italic>z</jats:italic> &lt; 20 if it is present during the recombination and reionization epochs. This field can also survive in the voids of the large-scale structure in the present day universe. We study the sensitivity reach of the gamma-ray technique for measurement of such a relatively strong cosmological magnetic field using deep exposure(s) of the nearest hard spectrum blazar(s) with CTA telescopes. We show that the gamma-ray measurement method can sense the primordial magnetic field with a strength of up to 10<jats:sup>−11</jats:sup> G. Combination of the cosmic microwave background and gamma-ray constraints can thus sense the full range of possible cosmological magnetic fields to confirm or rule out their relevance to the problem of the origin of cosmic magnetic fields, as well as their influence on recombination and reionization epochs.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Accurate measurements of electron density are critical for determination of the plasma properties in the solar corona. We compare the electron densities diagnosed from Fe <jats:sc>xiii</jats:sc> lines observed by the Extreme-Ultraviolet Imaging Spectrometer (EIS) onboard the Hinode mission with the near-infrared (NIR) measurements provided by the ground-based Coronal Multichannel Polarimeter (CoMP). To do that, the emissivity-ratio method based on all available observed lines of Fe <jats:sc>xiii</jats:sc> is used for both EIS and CoMP. The EIS diagnostics is further supplemented by the results from Fe <jats:sc>xii</jats:sc> lines. We find excellent agreement, within 10%, between the electron densities measured from both extreme-ultraviolet and NIR lines. In the five regions selected for detailed analysis, we obtain electron densities of log(<jats:italic>N</jats:italic> <jats:sub>e</jats:sub> [cm<jats:sup>−3</jats:sup>]) = 8.2–8.6. Where available, the background subtraction has a significant impact on the diagnostics, especially on the NIR lines, where the loop contributes less than a quarter of the intensity measured along the line of sight. For the NIR lines, we find that the line center intensities are not affected by stray light within the instrument, and recommend using these for density diagnostics. The measurements of the Fe <jats:sc>xiii</jats:sc> NIR lines represent a viable method for density diagnostics using ground-based instrumentation.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present observations of the magnetic field <jats:inline-formula> <jats:tex-math> <?CDATA ${\boldsymbol{B}}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabccd1ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> in the outermost region of the heliosheath made by Voyager 2 (V2) from 2016 to 2018.6, just before V2 entered the magnetic barrier inside of the heliopause. The average magnetic field strength (<jats:italic>B</jats:italic>) during this interval was relatively large, 0.135 nT, mainly due to numerous merged interaction regions. Sector structure was observed, and the direction of azimuthal angle <jats:italic>λ</jats:italic> was primarily close to the Parker spiral magnetic field directions 90° and 270°. Thus, the heliospheric current sheet extended to relatively high southern latitudes poleward of V2 (&gt;30°). On smaller scales, distributions of daily increments in <jats:italic>B</jats:italic> and the components of <jats:inline-formula> <jats:tex-math> <?CDATA ${\boldsymbol{B}}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabccd1ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> from 2016 to 2018.6 were accurately described by <jats:italic>q</jats:italic>-Gaussian distributions. The average values of the nonextensivity parameter <jats:italic>q</jats:italic> for one-day increments of the components decreased from <jats:italic>q</jats:italic> = 1.7 ± 0.01 during 2016 (near solar maximum) to <jats:italic>q</jats:italic> = 1.3 ± 0.1 during 2017 and 2018, as solar activity declined. The <jats:italic>BT</jats:italic> direction was close to the average magnetic field direction, and V2 measured primarily compressible fluctuations. These new results are also presented in the context of an overview of the observations of the magnetic field in the heliosheath from the termination shock crossing to the heliopause.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study the dynamics of shock waves observed in the umbra of a sunspot using the spectroscopic observations from the Interface Region Imaging Spectrograph. The presence of a shock significantly deforms the shape of the spectral lines of Mg <jats:sc>ii</jats:sc>, C <jats:sc>ii</jats:sc>, and Si <jats:sc>iv</jats:sc>. We found that C <jats:sc>ii</jats:sc> 1335.71 Å and Si <jats:sc>iv</jats:sc> 1393.75 Å show double-peaked profiles that change to a single peak later on. However, the Mg <jats:sc>ii</jats:sc> <jats:italic>h</jats:italic> 2803.53 Å line first shows flat-top profiles that change into double peaks followed by the single peak. To study the shock dynamics, we isolate the shock component from the spectra by fitting two Gaussians. We find that the lifetime of the shock is largest in the Mg <jats:sc>ii</jats:sc> <jats:italic>h</jats:italic> 2803.53 Å line. Moreover, the plasma motion shows both the acceleration and deceleration phases of the shock. Yet, in C <jats:sc>ii</jats:sc> 1335.71 Å and Si <jats:sc>iv</jats:sc> 1393.75 Å, only the deceleration phase is observed. We observe a strong correlation between the largest blueshift of the shock and deceleration for all three spectral lines. We find a positive (negative) correlation between intensities contributed by the shocks in Mg <jats:sc>ii</jats:sc> and C <jats:sc>ii</jats:sc> (Si <jats:sc>iv</jats:sc>). This suggests that the shocks are first amplified in C <jats:sc>ii</jats:sc>, followed by a decline in the height range corresponding to Si <jats:sc>iv</jats:sc>. These results may indicate the dissipation of shocks above the formation height of C <jats:sc>ii</jats:sc>, and the shocks may have important roles in the dynamics of the upper chromosphere and transition region above sunspots.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In a previous paper, we found that perpendicular and parallel proton temperatures are clearly associated with the proton-scale turbulence in the solar wind, and magnetic helicity signature appears to be an important indicator in the association. Based on 15 yr of in situ measurements, the present paper further investigates the magnetic helicity of solar wind turbulence and its role in regulating magnetic energy spectra and proton temperatures. Results show that the presence of the helicity signature is very common in solar wind turbulence at scales <jats:inline-formula> <jats:tex-math> <?CDATA $0.3\lesssim k{\rho }_{p}\lesssim 1$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, with <jats:italic>k</jats:italic> being the wavenumber and <jats:italic>ρ</jats:italic> <jats:sub> <jats:italic>p</jats:italic> </jats:sub> the proton gyroradius. The sign of the helicity is mostly positive, indicating the dominance of right-handed polarization of the turbulence. The helicity magnitude usually increases with <jats:italic>k</jats:italic> and <jats:inline-formula> <jats:tex-math> <?CDATA ${\beta }_{\parallel p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn2.gif" xlink:type="simple" /> </jats:inline-formula> (the proton parallel beta) when <jats:inline-formula> <jats:tex-math> <?CDATA $k{\rho }_{p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn3.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math> <?CDATA ${\beta }_{\parallel p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn4.gif" xlink:type="simple" /> </jats:inline-formula> are less than unity. As helicity magnitude increases, the power index of the energy spectrum becomes more negative, and the proton temperatures <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\perp p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn5.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\parallel p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn6.gif" xlink:type="simple" /> </jats:inline-formula> rise significantly, where <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\perp p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn7.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\parallel p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn8.gif" xlink:type="simple" /> </jats:inline-formula> are the perpendicular and parallel temperatures with respect to the background magnetic field. In particular, the rise of <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\perp p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn9.gif" xlink:type="simple" /> </jats:inline-formula> is faster than <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\parallel p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn10.gif" xlink:type="simple" /> </jats:inline-formula> when <jats:inline-formula> <jats:tex-math> <?CDATA ${\beta }_{\parallel p}\lt 1$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn11.gif" xlink:type="simple" /> </jats:inline-formula> is satisfied. The faster rise of <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\perp p}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca3bieqn12.gif" xlink:type="simple" /> </jats:inline-formula> with the helicity magnitude may be interpreted as the result of the preferentially perpendicular heating of solar wind protons by kinetic Alfvén wave turbulence.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The epoch of reionization (EoR) marks the end of the Cosmic Dawn and the beginning of large-scale structure formation in the universe. The impulsive ionization fronts (I-fronts) heat and ionize the gas within the reionization bubbles in the intergalactic medium (IGM). The temperature during this process is a key yet uncertain ingredient in current models. Typically, reionization simulations assume that all baryonic species are in instantaneous thermal equilibrium with each other during the passage of an I-front. Here we present a new model of the temperature evolution for the ionization front by studying nonequilibrium effects. In particular, we include the energy transfer between major baryon species (<jats:italic>e</jats:italic> <jats:sup>−</jats:sup>, H <jats:sc>i</jats:sc>, H <jats:sc>ii</jats:sc>, He <jats:sc>i</jats:sc>, and He <jats:sc>ii</jats:sc>) and investigate their impacts on the post-ionization front temperature <jats:italic>T</jats:italic> <jats:sub>re</jats:sub>. For a better step-size control when solving the stiff equations, we implement an implicit method and construct an energy transfer rate matrix. We find that the assumption of equilibration is valid for a nonrelativistic ionization front (speed less than <jats:inline-formula> <jats:tex-math> <?CDATA ${10}^{9}\,\mathrm{cm}\,{{\rm{s}}}^{-1}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca38ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>), but deviations from equilibrium occur for faster fronts. The post-front temperature <jats:italic>T</jats:italic> <jats:sub>re</jats:sub> is lower by up to 19.7% (at <jats:inline-formula> <jats:tex-math> <?CDATA $3\times {10}^{9}\,\mathrm{cm}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabca38ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> s<jats:sup>−1</jats:sup>) or 30.8% (at 10<jats:sup>10</jats:sup> cm s<jats:sup>−1</jats:sup>) relative to the equilibrium case.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>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 <jats:inline-formula> <jats:tex-math> <?CDATA $20\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabce61ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> 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 <jats:inline-formula> <jats:tex-math> <?CDATA $\sim {10}^{15\mbox{--}16}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabce61ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> 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.</jats:p>