Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>A set of simulations with a 3D global climate model are performed to investigate the roles of obliquity and rotation period in the habitability of Earthlike exoplanets. The simulations cover the obliquity–rotation parameter space, from 0° to 90° in obliquity and 1–128 days in rotation period. The simulated global mean temperatures are warmest at 45° obliquity with fast rotations, due to the modification of the greenhouse effect from the spatial redistribution of clouds and water vapor. The slow-moving insolation–cloud mechanism, previously found in simulations with slow rotations and zero obliquity, also produces a cooling trend from intermediate obliquity to high obliquity, with the coldest climate occurring at 90° obliquity for all rotation periods. At low obliquities and fast rotation, persistent snow and sea ice can form, producing cooler temperatures. A Climate Habitability metric is defined, based on temperature and precipitation, which compares well with observations when applied to a simulation using Earth’s obliquity and rotation. Over a wider range of obliquity and rotation period, the Climate Habitability ranges from 10% to 70% of the terrestrial area. Overall, the simulated global mean surface temperature shows a much larger spread across the range of simulated rotation periods at 45° obliquity compared to 0° obliquity. Therefore, we conclude that 3D exoplanet simulations using intermediate obliquities (e.g., 45°) instead of 0° will reveal a wider range of possible climate conditions for specific orbital configurations. In addition, Earth’s climate habitability can increase by 25% if the obliquity increases from 23.°5 to 45°.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Isolated black holes and neutron stars can be revealed through the observation of long-duration gravitational microlensing events. A few candidates have been found in surveys of stars in the direction of the Galactic bulge. Recently, thanks to the addition of astrometric information at milliarcsecond level, it has been possible to reduce the uncertainties in the masses and distances for some of these “dark” gravitational lenses and select the most promising candidates. These isolated compact objects might emit X-rays powered by accretion from the interstellar medium. Using data of the Chandra, XMM-Newton, and INTEGRAL satellites, we searched for X-ray emission in the isolated black hole candidate OGLE-2011-BLG-0462, and in several other putative collapsed objects found with gravitational microlensing. OGLE-2011-BLG-0462 has been recently interpreted as a 7.1 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> black hole at a distance of 1.6 kpc, although a different group obtained a mass range (1.6–4.4 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>) that cannot exclude a massive neutron star. We have derived upper limits on the flux from OGLE-2011-BLG-0462 of 9 × 10<jats:sup>−15</jats:sup> erg cm<jats:sup>−2</jats:sup> s<jats:sup>−1</jats:sup> in the 0.5–7 keV range and ∼2 × 10<jats:sup>−12</jats:sup> erg cm<jats:sup>−2</jats:sup> s<jats:sup>−1</jats:sup> in the 17–60 keV range. The implied X-ray luminosity is consistent with the small radiative efficiency expected for a black hole and disfavors a neutron star interpretation. Limits down to a factor of about five lower are obtained for the soft X-ray flux of other candidates, but their interpretation is affected by larger uncertainties in the masses, distances, and spatial velocities.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Water worlds have been hypothesized as an alternative to photoevaporation in order to explain the gap in the radius distribution of Kepler exoplanets. We explore water worlds within the framework of a joint mass–radius–period distribution of planets fit to a sample of transiting Kepler exoplanets, a subset of which have radial velocity mass measurements. We employ hierarchical Bayesian modeling to create a range of ten mixture models that include multiple compositional subpopulations of exoplanets. We model these subpopulations—including planets with gaseous envelopes, evaporated rocky cores, evaporated icy cores, intrinsically rocky planets, and intrinsically icy planets—in different combinations in order to assess which combinations are most favored by the data. Using cross-validation, we evaluate the support for models that include planets with icy compositions compared to the support for models that do not, finding broad support for both. We find significant population-level degeneracies between subpopulations of water worlds and planets with primordial envelopes. Among models that include one or more icy-core subpopulations, we find a wide range for the fraction of planets with icy compositions, with a rough upper limit of 50%. Improved data sets or alternative modeling approaches may be able to better distinguish between these subpopulations of planets.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Cosmic rays are crucial to the chemistry of molecular clouds and their evolution. They provide essential ionizations, dissociations, heating, and energy to the cold, dense cores. As cosmic rays pierce through clouds they are attenuated and lose energy, which leads to a dependency on the column density of a system. The detailed effects these particles have on the central regions still need to be fully understood. Here, we revisit how cosmic rays are treated in the UCLCHEM chemical modeling code by including both ionization rate and H<jats:sub>2</jats:sub> dissociation rate dependencies alongside the production of cosmic ray induced excited species and we study in detail the effects of these treatments on the chemistry of pre-stellar cores. We find that these treatments can have significant effects on chemical abundances, up to several orders of magnitude, depending on the physical conditions. The ionization dependency is the most significant treatment influencing chemical abundances through the increased presence of ionized species, grain desorptions, and enhanced chemical reactions. Comparisons to chemical abundances derived from observations show the new treatments reproduce these observations better than the standard handling. It is clear that more advanced treatments of cosmic rays are essential to chemical models and that including this type of dependency provides more accurate chemical representations.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We report the first detection of deuterated water (HDO) toward an extragalactic hot core. The HDO 2<jats:sub>11</jats:sub>–2<jats:sub>12</jats:sub> line has been detected toward hot cores N 105–2 A and 2 B in the N 105 star-forming region in the low-metallicity Large Magellanic Cloud (LMC) dwarf galaxy with the Atacama Large Millimeter/submillimeter Array (ALMA). We have compared the HDO line luminosity (<jats:italic>L</jats:italic> <jats:sub>HDO</jats:sub>) measured toward the LMC hot cores to those observed toward a sample of 17 Galactic hot cores covering three orders of magnitude in <jats:italic>L</jats:italic> <jats:sub>HDO</jats:sub>, four orders of magnitude in bolometric luminosity (<jats:italic>L</jats:italic> <jats:sub>bol</jats:sub>), and a wide range of Galactocentric distances (thus metallicities). The observed values of <jats:italic>L</jats:italic> <jats:sub>HDO</jats:sub> for the LMC hot cores fit very well into the <jats:italic>L</jats:italic> <jats:sub>HDO</jats:sub> trends with <jats:italic>L</jats:italic> <jats:sub>bol</jats:sub> and metallicity observed toward the Galactic hot cores. We have found that <jats:italic>L</jats:italic> <jats:sub>HDO</jats:sub> seems to be largely dependent on the source luminosity, but metallicity also plays a role. We provide a rough estimate of the H<jats:sub>2</jats:sub>O column density and abundance ranges toward the LMC hot cores by assuming that HDO/H<jats:sub>2</jats:sub>O toward the LMC hot cores is the same as that observed in the Milky Way; the estimated ranges are systematically lower than Galactic values. The spatial distribution and velocity structure of the HDO emission in N 105–2 A is consistent with HDO being the product of the low-temperature dust grain chemistry. Our results are in agreement with the astrochemical model predictions that HDO is abundant regardless of the extragalactic environment and should be detectable with ALMA in external galaxies.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present spatially resolved morphological properties of [C <jats:sc>II</jats:sc>] 158 <jats:italic>μ</jats:italic>m, [O <jats:sc>III</jats:sc>] 88 <jats:italic>μ</jats:italic>m, dust, and rest-frame ultraviolet (UV) continuum emission for A1689-zD1, a strongly lensed, sub-L* galaxy at <jats:italic>z</jats:italic> = 7.13, by utilizing deep Atacama Large Millimeter/submillimeter Array (ALMA) and Hubble Space Telescope (HST) observations. While the [O <jats:sc>III</jats:sc>] line and UV continuum are compact, the [C <jats:sc>II</jats:sc>] line is extended up to a radius of <jats:italic>r</jats:italic> ∼ 12 kpc. Using multi-band rest-frame far-infrared continuum data ranging from 52 to 400 <jats:italic>μ</jats:italic>m, we find an average dust temperature and emissivity index of <jats:inline-formula> <jats:tex-math> <?CDATA ${T}_{\mathrm{dust}}={41}_{-14}^{+17}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>dust</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>41</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>14</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>17</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac795bieqn1.gif" xlink:type="simple" /> </jats:inline-formula> K and <jats:inline-formula> <jats:tex-math> <?CDATA $\beta ={1.7}_{-0.7}^{+1.1}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>β</mml:mi> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>1.7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>1.1</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac795bieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, respectively, across the galaxy. We find slight differences in the dust continuum profiles at different wavelengths, which may indicate that the dust temperature decreases with distance. We map the star formation rate (SFR) via IR and UV luminosities and determine a total SFR of 37 ± 1<jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>yr<jats:sup>−1</jats:sup> with an obscured fraction of 87%. While the [O <jats:sc>III</jats:sc>] line is a good tracer of the SFR, the [C <jats:sc>II</jats:sc>] line shows deviation from the local <jats:italic>L</jats:italic> <jats:sub>[C <jats:sc>II</jats:sc>]</jats:sub>-SFR relations in the outskirts of the galaxy. Finally, we observe a clear difference in the line profile between [C <jats:sc>II</jats:sc>] and [O <jats:sc>III</jats:sc>], with significant residuals (∼5<jats:italic>σ</jats:italic>) in the [O <jats:sc>III</jats:sc>] line spectrum after subtracting a single Gaussian model. This suggests a possible origin of the extended [C <jats:sc>II</jats:sc>] structure from the cooling of hot ionized outflows. The extended [C <jats:sc>II</jats:sc>] and high-velocity [O <jats:sc>III</jats:sc>] emission may both contribute in part to the high <jats:italic>L</jats:italic> <jats:sub>[O <jats:sc>III</jats:sc>]</jats:sub>/<jats:italic>L</jats:italic> <jats:sub>[C <jats:sc>II</jats:sc>]</jats:sub> ratios recently reported in <jats:italic>z</jats:italic> &gt; 6 galaxies.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Supernovae of Type Iax (SNe Iax) are an accepted faint subclass of hydrogen-free supernovae. Their origin, the nature of the progenitor systems, however, is an open question. Recent studies suggest that the weak deflagration explosion of a near-Chandrasekhar-mass white dwarf in a binary system with a helium-star donor could be the origin of SNe Iax. In this scenario, the helium-star donor is expected to survive the explosion. We use the one-dimensional stellar evolution codes <jats:sc>MESA</jats:sc> and Kepler to follow the postimpact evolution of the surviving helium companion stars. The stellar models are based on our previous hydrodynamical simulations of ejecta–donor interaction, and we explore the observational characteristics of these surviving helium companions. We find that the luminosities of the surviving helium companions increase significantly after the impact: they could vary from 2500 <jats:italic>L</jats:italic> <jats:sub>⊙</jats:sub> to 16,000 <jats:italic>L</jats:italic> <jats:sub>⊙</jats:sub> for a Kelvin–Helmholtz timescale of about 10<jats:sup>4</jats:sup> yr. After the star reaches thermal equilibrium, it evolves as an O-type hot subdwarf (sdO) star and continues its evolution along the evolutionary track of a normal sdO star with the same mass. Our results will help to identify the surviving helium companions of SNe Iax in future observations and to place new constraints on their progenitor models.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We explore the validity of the recently reported fundamental plane (FP) relation of <jats:italic>γ</jats:italic>-ray pulsars using 190 pulsars included in the latest 4FGL-DR3 catalog. This sample number is more than twice as large as that of the original study. The FP relation incorporates four parameters, i.e., the spin-down power, <jats:inline-formula> <jats:tex-math> <?CDATA $\dot{{ \mathcal E }}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac78e3ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, the surface magnetic field, <jats:italic>B</jats:italic> <jats:sub>⋆</jats:sub>, the total <jats:italic>γ</jats:italic>-ray luminosity, <jats:italic>L</jats:italic> <jats:sub> <jats:italic>γ</jats:italic> </jats:sub>, and a spectral cutoff energy, <jats:italic>ϵ</jats:italic> <jats:sub>cut</jats:sub>. The derivation of <jats:italic>ϵ</jats:italic> <jats:sub>cut</jats:sub> is the most intriguing one because <jats:italic>ϵ</jats:italic> <jats:sub>cut</jats:sub> depends on the proper interpretation of the available phase-averaged spectra. We construct synthetic phase-averaged spectra, guided by the few existing phase-resolved ones, to find that the best-fit cutoff energy, <jats:italic>ϵ</jats:italic> <jats:sub>c1</jats:sub>, corresponding to a purely exponential cutoff (plus a power-law) spectral form, is the parameter that optimally probes the maximum cutoff energy of the emission that originates from the core of the dissipative region, i.e., the equatorial current sheet. Computing this parameter for the 190 4FGL pulsars, we find that the resulting FP relation, i.e., the <jats:italic>γ</jats:italic>-ray luminosity in terms of the other observables, reads as <jats:inline-formula> <jats:tex-math> <?CDATA ${L}_{\gamma }={10}^{14.3\pm 1.3}{({\epsilon }_{{\rm{c}}1}/\mathrm{MeV})}^{1.39\pm 0.17}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>L</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>γ</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>14.3</mml:mn> <mml:mo>±</mml:mo> <mml:mn>1.3</mml:mn> </mml:mrow> </mml:msup> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>ϵ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mi>MeV</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>1.39</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.17</mml:mn> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac78e3ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> <jats:inline-formula> <jats:tex-math> <?CDATA ${({B}_{\star }/{\rm{G}})}^{0.12\pm 0.03}{(\dot{{ \mathcal E }}/\mathrm{erg}\,{{\rm{s}}}^{-1})}^{0.39\pm 0.05}\,\mathrm{erg}\,{{\rm{s}}}^{-1};$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>B</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⋆</mml:mo> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mi mathvariant="normal">G</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>0.12</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.03</mml:mn> </mml:mrow> </mml:msup> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mover accent="true"> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mi>erg</mml:mi> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>0.39</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.05</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.50em" /> <mml:mi>erg</mml:mi> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo>;</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac78e3ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> this is in good agreement with both the empirical relation reported by Kalapotharakos et al. and the theoretically predicted relation for curvature radiation. Finally, we revisit the radiation reaction limited condition, to find it is a sufficient but not necessary condition for the theoretical derivation of the FP relation. However, the assumption of the radiation reaction limited acceleration reveals the underlying accelerating electric field component and its scaling with <jats:inline-formula> <jats:tex-math> <?CDATA $\dot{{ \mathcal E }}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac78e3ieqn4.gif" xlink:type="simple" /> </jats:inline-formula>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Analyzing the evolution of magnetic helicity flux at different atmospheric heights is key for identifying its role in the dynamics of active regions (ARs). The three-dimensional (3D) magnetic field of both flaring and nonflaring ARs is constructed using potential field extrapolations, enabling the derivation of emergence, shearing, and total magnetic helicity components at a range of atmospheric heights. An analysis of temporal oscillations of the derived components shows that the largest significant period of the three helicity fluxes are common (within ±2 hr) from the photosphere up to at least 1 Mm for flaring ARs—being consistent with the presence of a coupled oscillatory behavior that is absent in the nonflaring ARs. We suggest that large, energetic solar eruptions may have been produced in ARs when the vertical and horizontal helicity flux components became a coupled oscillatory system in the low solar atmosphere.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>This is the second paper in a series aimed at modeling the black hole (BH) mass function from the stellar to the (super)massive regime. In the present work, we focus on (super)massive BHs and provide an ab initio computation of their mass function across cosmic time. We consider two main mechanisms to grow the central BH that are expected to cooperate in the high-redshift star-forming progenitors of local massive galaxies. The first is the gaseous dynamical friction process, which can cause the migration toward the nuclear regions of stellar mass BHs originated during the intense bursts of star formation in the gas-rich host progenitor galaxy and the buildup of a central heavy BH seed, <jats:italic>M</jats:italic> <jats:sub>•</jats:sub> ∼ 10<jats:sup>3−5</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>, within short timescales of ≲some 10<jats:sup>7</jats:sup> yr. The second mechanism is the standard Eddington-type gas disk accretion onto the heavy BH seed through which the central BH can become (super)massive, <jats:italic>M</jats:italic> <jats:sub>•</jats:sub> ∼ 10<jats:sup>6−10</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>, within the typical star formation duration, ≲1 Gyr, of the host. We validate our semiempirical approach by reproducing the observed redshift-dependent bolometric AGN luminosity functions and Eddington ratio distributions and the relationship between the star formation and the bolometric luminosity of the accreting central BH. We then derive the relic (super)massive BH mass function at different redshifts via a generalized continuity equation approach and compare it with present observational estimates. Finally, we reconstruct the overall BH mass function from the stellar to the (super)massive regime over more than 10 orders of magnitudes in BH mass.</jats:p>