Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>Modern and future surveys effectively provide a panchromatic view for large numbers of extragalactic objects. Consistently modeling these multiwavelength survey data is a critical but challenging task for extragalactic studies. The Code Investigating GALaxy Emission (<jats:sc>cigale</jats:sc>) is an efficient <jats:sc>python</jats:sc> code for spectral energy distribution (SED) fitting of galaxies and active galactic nuclei (AGNs). Recently, a major extension of <jats:sc>cigale</jats:sc> (named <jats:sc>x-cigale</jats:sc>) has been developed to account for AGN/galaxy X-ray emission and improve AGN modeling at UV-to-IR wavelengths. Here, we apply <jats:sc>x-cigale</jats:sc> to different samples, including Cosmological Evolution Survey (COSMOS) spectroscopic type 2 AGNs, Chandra Deep Field-South X-ray detected normal galaxies, Sloan Digital Sky Survey quasars, and COSMOS radio objects. From these tests, we identify several weaknesses of <jats:sc>x-cigale</jats:sc> and improve the code accordingly. These improvements are mainly related to AGN intrinsic X-ray anisotropy, X-ray binary emission, AGN accretion-disk SED shape, and AGN radio emission. These updates improve the fit quality and allow for new interpretation of the results, based on which we discuss physical implications. For example, we find that AGN intrinsic X-ray anisotropy is moderate, and can be modeled as <jats:inline-formula> <jats:tex-math> <?CDATA ${L}_{X}(\theta )\propto 1+\cos \theta $?> </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>X</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mi>θ</mml:mi> <mml:mo stretchy="false">)</mml:mo> <mml:mo>∝</mml:mo> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo> <mml:mi>cos</mml:mi> <mml:mi>θ</mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac4971ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, where <jats:italic>θ</jats:italic> is the viewing angle measured from the AGN axis. We merge the new code into the major branch of <jats:sc>cigale</jats:sc>, and publicly release this new version as <jats:sc>cigale v2022.0</jats:sc> on <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://cigale.lam.fr" xlink:type="simple">https://cigale.lam.fr</jats:ext-link>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Christoph Scheiner was one of the most outstanding astronomers in the history of sunspot observations. His book, <jats:italic>Rosa Ursina</jats:italic>, is the reference work regarding the study of the earliest sunspot records. The sunspot observations compiled by Scheiner in <jats:italic>Rosa Ursina</jats:italic> and <jats:italic>Prodomus</jats:italic>, including records made by other observers, forms one of the main references of the observations known for that period—particularly around the 1620s. Thus, his work is crucial to determine the solar activity level of the first solar cycles of the telescopic era. The number of sunspot groups recorded in Scheiner’s documentary sources has been included in the existing sunspot group number databases. However, we have detected significant errors in the number of groups currently assigned to Scheiner’s records. In this work, we reanalyze the information in Scheiner’s source documents. Consequently, the standard 11 yr solar cycle shape for the second solar cycle of the telescopic era, which is not clear in previous studies, now becomes evident. In addition, the highest daily number of groups recorded during this cycle (eight groups) is 20% less than in the one included in the existing sunspot group number databases. Using the hypergeometrical probability distribution, we find that solar minima in 2008–2009 and 2018–2019 are comparable to the most probable solar activity level of the minimum around 1632. In particular, the estimated lower limit for the solar activity in 1632 is even comparable with the solar activity level in 2008 and 2018.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Accreting X-ray pulsars undergo luminous X-ray outbursts during which the luminosity-dependent spectral and timing features of the neutron star’s emission can be analyzed in detail, thus shedding light on the accretion regime at work. We took advantage of a monitoring campaign that was performed with NuSTAR, Swift/XRT, AstroSat and NICER to follow the Be/X-ray Binary 2S 1553-542 along one of its rare outbursts, and thus trace its spectral and timing evolution. We report the discovery of a luminosity-dependent cyclotron line energy for the first time in this source. The pulse profiles and pulsed fraction also show variability along the outburst, which is consistent with the interpretation that the source transitions from the subcritical to the supercritical accretion regime, separated by a critical luminosity of <jats:italic>L</jats:italic> <jats:sub>crit</jats:sub> ≈ 4 × 10<jats:sup>37</jats:sup> erg s<jats:sup>−1</jats:sup>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The Neutron Star Interior Composition Explorer (NICER) records exceptional data on pulsars’ energy-dependent X-ray pulse profiles. However, in searching for evidence of pulsations, Guillot et al. (2019) introduce a procedure to select an ordered subset of data that maximizes a detection statistic (the H-test). I show that this can degrade subsequent analyses using an idealized model with stationary expected count rates from both noise and signal. Specifically, the data-selection procedure biases the inferred mean count rate to be too low and the inferred pulsation amplitude to be too high, and the size of these biases scales strongly with the amount of data that is rejected and the true signal amplitude. The procedure also alters the H-test’s null distribution, rendering nominal significance estimates overly optimistic. While the idealized model does not capture all the complexities of real NICER data, it suggests that these biases could be important for NICER’s observations of J0740+6620 and other faint pulsars (observations of J0030+0451 are likely less affected). I estimate that these effects may introduce a bias of <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal O }(10 \% )$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic"></mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mn>10</mml:mn> <mml:mo>%</mml:mo> <mml:mo stretchy="false">)</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac517cieqn1.gif" xlink:type="simple" /> </jats:inline-formula> on average in the inferred modulation depth of lightcurves like J0740+6620's, and may be as large as <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal O }(50 \% )$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic"></mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mn>50</mml:mn> <mml:mo>%</mml:mo> <mml:mo stretchy="false">)</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac517cieqn2.gif" xlink:type="simple" /> </jats:inline-formula> for fainter pulsars. However, the change for a single data set like J0740+6620 is expected to be a shift between −5% and +20%. This could imply that the lower limit on J0740+6620's radius is slightly larger than it should be, although preliminary investigations suggest the radius constraints shift to larger radii by <jats:inline-formula> <jats:tex-math> <?CDATA ${ \mathcal O }(1 \% )$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="italic"></mml:mi> <mml:mo stretchy="false">(</mml:mo> <mml:mn>1</mml:mn> <mml:mo>%</mml:mo> <mml:mo stretchy="false">)</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac517cieqn3.gif" xlink:type="simple" /> </jats:inline-formula> with the same overall statistical precision using real J0740+6620 data.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Results from 2.5D and 3D studies of the onset and development of the tearing instability are presented, using high-fidelity resistive MHD simulations. A limited parameter study of the strength of the reconnecting field (or shear angle) was performed. An initially simple 1D equilibrium was used, consisting of a modified force-free current sheet, with periodic boundary conditions in all directions. In all cases, the linear and nonlinear evolution led to a primary current sheet between two large flux ropes. The global reconnection rate during this later stage was analyzed in all simulations. It was found that in 2.5D the primary current sheet fragmented owing to plasmoids, and as expected, the global reconnection rate, calculated using multiple methods, increases with the strength of the reconnecting field owing to a stronger Alfvén speed. In 3D, the presence of interacting oblique modes of the tearing instability complicates the simple 2.5D picture, entangling the magnetic field of the inflow and introducing a negative effect on the reconnection rate. The two competing effects of stronger Alfvén speed and entangling, which both increase with the strength of the reconnecting field, resulted in a decrease in the reconnection rate with increasing reconnecting field. For all simulations, the 3D rates were less than in 2.5D but suggest that as one goes to weak reconnecting field (or strong guide field) the system becomes more 2.5D-like and the 2.5D and 3D rates converge. These results have relevance to situations like nanoflare heating and flare current sheets in the corona.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The blazar <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="object" xlink:href="TXS 0506=056" xlink:type="simple">TXS 0506+056</jats:named-content> got into the spotlight of the astrophysical community in 2017 September, when a high-energy neutrino detected by IceCube (IceCube-170922A) was associated at the 3<jats:italic>σ</jats:italic> level with a <jats:italic>γ</jats:italic>-ray flare from this source. This multi-messenger photon-neutrino association remains, as per today, the most significant association ever observed. TXS 0506+056 was a poorly studied object before the IceCube-170922A event. To better characterize its broadband emission, we organized a multiwavelength campaign lasting 16 months (2017 November to 2019 February), covering the radio band (Metsähovi, OVRO), the optical/UV (ASAS-SN, KVA, REM, Swift/UVOT), the X-rays (Swift/XRT, NuSTAR), the high-energy <jats:italic>γ</jats:italic> rays (Fermi/LAT), and the very high-energy (VHE) <jats:italic>γ</jats:italic> rays (MAGIC). In <jats:italic>γ</jats:italic> rays, the behavior of the source was significantly different from the behavior in 2017: MAGIC observations show the presence of flaring activity during 2018 December, while the source only shows an excess at the 4<jats:italic>σ</jats:italic> level during the rest of the campaign (74 hr of accumulated exposure); Fermi/LAT observations show several short (on a timescale of days to a week) flares, different from the long-term brightening of 2017. No significant flares are detected at lower energies. The radio light curve shows an increasing flux trend that is not seen in other wavelengths. We model the multiwavelength spectral energy distributions in a lepto-hadronic scenario, in which the hadronic emission emerges as Bethe-Heitler and pion-decay cascade in the X-rays and VHE <jats:italic>γ</jats:italic> rays. According to the model presented here, the 2018 December <jats:italic>γ</jats:italic>-ray flare was connected to a neutrino emission that was too brief and not bright enough to be detected by current neutrino instruments.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We use a semiempirical model to investigate the radial acceleration relation (RAR) in a cold dark matter (CDM) framework. Specifically, we build 80 model galaxies covering the same parameter space as the observed galaxies in the SPARC database, assigning them to dark matter (DM) halos using abundance-matching and halo mass–concentration relations. We consider several abundance-matching relations, finding some to be a better match to the kinematic data than others. We compute the unavoidable gravitational interactions between baryons and their DM halos, leading to an overall compression of the original Navarro–Frenk–White (NFW) halos. Before halo compression, high-mass galaxies lie approximately on the observed RAR, whereas low-mass galaxies display up-bending “hooks” at small radii due to DM cusps, making them deviate systematically from the observed relation. After halo compression, the initial NFW halos become more concentrated at small radii, making larger contributions to rotation curves. This increases the total accelerations, moving all model galaxies away from the observed relation. These systematic deviations suggest that the CDM model with abundance matching alone cannot explain the observed RAR. Further effects (e.g., feedback) would need to counteract the compression with precisely the right amount of halo expansion, even in high-mass galaxies with deep potential wells where such effects are generally predicted to be negligible.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Calcium-rich (Ca-rich) transients are a new class of supernovae (SNe) that are known for their comparatively rapid evolution, modest peak luminosities, and strong nebular calcium emission lines. Currently, the progenitor systems of Ca-rich transients remain unknown. Although they exhibit spectroscopic properties not unlike core-collapse Type Ib/c SNe, nearly half are found in the outskirts of their host galaxies, which are predominantly elliptical, suggesting a closer connection to the older stellar populations of SNe Ia. In this paper, we present a compilation of publicly available multiwavelength observations of all known and/or suspected host galaxies of Ca-rich transients ranging from far-UV to IR, and use these data to characterize their stellar populations with <jats:sc>prospector</jats:sc>. We estimate several galaxy parameters including integrated star formation rate, stellar mass, metallicity, and age. For nine host galaxies, the observations are sensitive enough to obtain nonparametric star formation histories, from which we recover SN rates and estimate probabilities that the Ca-rich transients in each of these host galaxies originated from a core-collapse versus Type Ia-like explosion. Our work supports the notion that the population of Ca-rich transients do not come exclusively from core-collapse explosions, and must either be only from white dwarf stars or a mixed population of white dwarf stars with other channels, potentially including massive star explosions. Additional photometry and explosion site spectroscopy of larger samples of Ca-rich host galaxies will improve these estimates and better constrain the ratio of white dwarf versus massive star progenitors of Ca-rich transients.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The solar wind is a highly turbulent plasma for which the mean rate of energy transfer <jats:italic>ε</jats:italic> has been measured for a long time using the Politano–Pouquet (PP98) exact law. However, this law assumes statistical homogeneity that can be violated by the presence of discontinuities. Here, we introduce a new method based on the inertial dissipation <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal D }}_{{\rm{I}}}^{\sigma }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">I</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac524bieqn1.gif" xlink:type="simple" /> </jats:inline-formula> whose analytical form is derived from incompressible magnetohydrodynamics; it can be considered as a weak and <jats:italic>local</jats:italic> (in space) formulation of the PP98 law whose expression is recovered after integration in space. We used <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal D }}_{{\rm{I}}}^{\sigma }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">I</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac524bieqn2.gif" xlink:type="simple" /> </jats:inline-formula> to estimate the local energy transfer rate at scale <jats:italic>σ</jats:italic> from the THEMIS-B and Parker Solar Probe data taken in the solar wind at different heliospheric distances. Our study reveals that discontinuities near the Sun lead to a strong energy transfer that affects a wide range of scales <jats:italic>σ</jats:italic>. We also observe that switchbacks seem to be characterized by a singular behavior with an energy transfer varying as <jats:italic>σ</jats:italic> <jats:sup>−3/4</jats:sup>, which slightly differs from classical discontinuities characterized by a <jats:italic>σ</jats:italic> <jats:sup>−1</jats:sup> scaling. A comparison between the measurements of <jats:italic>ε</jats:italic> and <jats:inline-formula> <jats:tex-math> <?CDATA ${{ \mathcal D }}_{{\rm{I}}}^{\sigma }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="italic"></mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">I</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac524bieqn3.gif" xlink:type="simple" /> </jats:inline-formula> shows that in general the latter is significantly larger than the former.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this paper, we provide clear direct evidence of multiple concurrent higher-order magnetohydrodynamic (MHD) modes in circular and elliptical sunspots by applying both proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) techniques on solar observational data. These techniques are well documented and validated in the areas of fluid mechanics, hydraulics, and granular flows but are relatively new to the field of solar physics. While POD identifies modes based on orthogonality in space and provides a clear ranking of modes in terms of their contribution to the variance of the signal, DMD resolves modes that are orthogonal in time. The clear presence of the fundamental slow sausage and kink body modes, as well as higher-order slow sausage and kink body modes, have been identified using POD and DMD analysis of the chromospheric H<jats:italic>α</jats:italic> line at 6562.808 Å for both the circular and elliptical sunspots. Additionally, for the various slow body modes, evidence for the presence of the fast surface kink mode was found in the circular sunspot. All of the MHD mode patterns were cross-correlated with their theoretically predicted counterparts, and we demonstrated that ellipticity cannot be neglected when interpreting MHD wave modes. The higher-order MHD wave modes are even more sensitive to irregularities in umbral cross-sectional shapes; hence, this must be taken into account for more accurate modeling of the modes in sunspots and pores.</jats:p>