Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>Compact Object Mergers: Population Astrophysics and Statistics (COMPAS; <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://compas.science" xlink:type="simple">https://compas.science</jats:ext-link>) is a public rapid binary population synthesis code. COMPAS generates populations of isolated stellar binaries under a set of parameterized assumptions in order to allow comparisons against observational data sets, such as those coming from gravitational-wave observations of merging compact remnants. It includes a number of tools for population processing in addition to the core binary evolution components. COMPAS is publicly available via the GitHub repository <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://github.com/TeamCOMPAS/COMPAS/" xlink:type="simple">https://github.com/TeamCOMPAS/COMPAS/</jats:ext-link>, and is designed to allow for flexible modifications as evolutionary models improve. This paper describes the methodology and implementation of COMPAS. It is a living document that will be updated as new features are added to COMPAS; the current document describes COMPAS v02.21.00.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Natural radiative lifetimes of 22 odd-parity levels of Re <jats:sc>ii</jats:sc> in the energy range between 43,937.7 and 65,572.3 cm<jats:sup>−1</jats:sup> were measured by the time-resolved laser-induced fluorescence method. To our knowledge, the lifetimes for 18 out of 22 levels were measured for the first time. The theoretical radiative lifetimes and branching fractions (BFs) for these levels were obtained from pseudorelativistic Hartree–Fock calculations including core-polarization effects. By combining the experimental lifetimes and calculated BFs, a set of semiempirical transition probabilities and oscillator strengths for 232 Re <jats:sc>ii</jats:sc> lines were determined. The radiative parameters obtained in the present work will greatly enrich the atomic database of Re <jats:sc>ii</jats:sc> and hence are expected to be helpful for astrophysicists in Re abundance evaluation of stars.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present component-separated maps of the primary cosmic microwave background/kinematic Sunyaev–Zel’dovich (SZ) amplitude and the thermal SZ Compton-<jats:italic>y</jats:italic> parameter, created using data from the South Pole Telescope (SPT) and the Planck satellite. These maps, which cover the ∼2500 deg<jats:sup>2</jats:sup> of the southern sky imaged by the SPT-SZ survey, represent a significant improvement over previous such products available in this region by virtue of their higher angular resolution (<jats:inline-formula> <jats:tex-math> <?CDATA $1\buildrel{\,\prime}\over{.} 25$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1</mml:mn> <mml:mo>.′</mml:mo> <mml:mn>25</mml:mn> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjsac35e9ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> for our highest-resolution Compton-<jats:italic>y</jats:italic> maps) and lower noise at small angular scales. In this work we detail the construction of these maps using linear combination techniques, including our method for limiting the correlation of our lowest-noise Compton-<jats:italic>y</jats:italic> map products with the cosmic infrared background. We perform a range of validation tests on these data products to test our sky modeling and combination algorithms, and we find good performance in all of these tests. Recognizing the potential utility of these data products for a wide range of astrophysical and cosmological analyses, including studies of the gas properties of galaxies, groups, and clusters, we make these products publicly available at <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://pole.uchicago.edu/public/data/sptsz_ymap" xlink:type="simple">http://pole.uchicago.edu/public/data/sptsz_ymap</jats:ext-link> and on the NASA/LAMBDA website.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>New spectrograms of multiply ionized iron have been recorded and analyzed, targeting the Fe <jats:sc>vii</jats:sc> spectrum. As a result, several previously unknown spectral lines and energy levels have been identified in this spectrum. These new data have been analyzed together with all previously published laboratory and astrophysical data on this spectrum. The energy levels have been interpreted using parametric calculations with Cowan codes. Radiative transition rates calculated in this work supplemented other previously published calculations in constructing a complete set of recommended transition probabilities. The ionization energy of Fe <jats:sc>vii</jats:sc> has been redetermined with a fivefold improvement in accuracy. Its new value is 1,007,928(20) cm<jats:sup>−1</jats:sup>, corresponding to 124.9671(25) eV.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a new empirical template for iron emission in active galactic nuclei (AGNs) covering the 4000–5600 Å range. The new template is based on a spectrum of the narrow-line Seyfert 1 galaxy Mrk 493 obtained with the Hubble Space Telescope. In comparison with the canonical iron template object I Zw 1, Mrk 493 has narrower broad-line widths, lower reddening, and a less extreme Eddington ratio, making it a superior choice for template construction. We carried out a multicomponent spectral decomposition to produce a template incorporating all the permitted and forbidden lines of Fe <jats:sc>ii</jats:sc> identified in the Mrk 493 spectrum over this wavelength range, as well as lines from Ti <jats:sc>ii</jats:sc>, Ni <jats:sc>ii</jats:sc>, and Cr <jats:sc>ii</jats:sc>. We tested the template by fitting it to AGN spectra spanning a broad range of iron emission properties, and we present a detailed comparison with fits using other widely used monolithic and multicomponent iron emission templates. The new template generally provides the best fit (lowest <jats:italic>χ</jats:italic> <jats:sup>2</jats:sup>) compared to other widely used monolithic empirical templates. In addition, the new template yields more accurate spectral measurements including a significantly better match of the derived Balmer line profiles (H<jats:italic>β</jats:italic>, H<jats:italic>γ</jats:italic>, H<jats:italic>δ</jats:italic>), in contrast with results obtained using the other templates. Our comparison tests show that the choice of iron template can introduce a systematic bias in measurements of the H<jats:italic>β</jats:italic> line width, which consequently impacts single-epoch black hole mass estimates by ∼0.1 dex on average and possibly up to ∼0.3–0.5 dex individually.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The four-year Kepler mission collected long-cadence images of the open clusters NGC 6791 and NGC 6819, known as “superstamps”. Each superstamp region is a 200 pixel square that captures thousands of cluster members, plus foreground and background stars, of which only the brightest were targeted for long- or short-cadence photometry during the Kepler mission. Using image subtraction photometry, we have produced light curves for every object in the Kepler Input Catalog that falls on the superstamps. The Increased Resolution Image Subtraction (IRIS) catalog includes light curves for 9150 stars, and contains a wealth of new data: 8427 of these stars were not targeted at all by Kepler, and we have increased the number of available quarters of long-cadence data for 382 stars. The catalog is available as a high-level science product on MAST, with both raw photometric data for each quarter and corrected light curves for all available quarters for each star. We also present an introduction to our implementation of image subtraction photometry and the open-source IRIS pipeline, alongside an overview of the data products, systematics, and catalog statistics.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The ExoClock project is an inclusive, integrated, and interactive platform that was developed to monitor the ephemerides of the Ariel targets to increase the mission efficiency. The project makes the best use of all available resources, i.e., observations from ground telescopes, midtime values from the literature, and finally, observations from space instruments. Currently, the ExoClock network includes 280 participants with telescopes capable of observing 85% of the currently known Ariel candidate targets. This work includes the results of ∼1600 observations obtained up to 2020 December 31 from the ExoClock network. These data in combination with ∼2350 midtime values collected from the literature are used to update the ephemerides of 180 planets. The analysis shows that 40% of the updated ephemerides will have an impact on future scheduling as either they have a significantly improved precision or they have revealed biases in the old ephemerides. With the new observations, the observing coverage and rate for half of the planets in the sample has been doubled or more. Finally, from a population perspective, we identify that the differences in the 2028 predictions between the old and the new ephemerides have an STD that is double what is expected from Gaussian uncertainties. These findings have implications for planning future observations, where we will need to account for drifts potentially greater than the prediction uncertainties. The updated ephemerides are open and accessible to the wider exoplanet community both from our Open Science Framework repository and our website.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a search for outer solar system objects in the 6 yr of data from the Dark Energy Survey (DES). The DES covered a contiguous 5000 deg<jats:sup>2</jats:sup> of the southern sky with ≈80,000 3 deg<jats:sup>2</jats:sup> exposures in the <jats:italic>grizY</jats:italic> filters between 2013 and 2019. This search yielded 812 trans-Neptunian objects (TNOs), one Centaur and one Oort cloud comet, 458 reported here for the first time. We present methodology that builds upon our previous search on the first 4 yr of data. All images were reprocessed with an optimized detection pipeline that leads to an average completeness gain of 0.47 mag per exposure, as well as improved transient catalog production and algorithms for linkage of detections into orbits. All objects were verified by visual inspection and by the “sub-threshold significance,” the signal-to-noise ratio in the stack of images in which its presence is indicated by the orbit, but no detection was reported. This yields a pure catalog complete to <jats:italic>r</jats:italic> ≈ 23.8 mag and distances 29 &lt; <jats:italic>d</jats:italic> &lt; 2500 au. The TNOs have minimum (median) of 7 (12) nights’ detections and arcs of 1.1 (4.2) yr, and will have <jats:italic>grizY</jats:italic> magnitudes available in a further publication. We present software for simulating our observational biases for comparisons of models to our detections. Initial inferences demonstrating the catalog’s statistical power are: the data are inconsistent with the CFEPS-L7 model for the classical Kuiper Belt; the 16 “extreme” TNOs (<jats:italic>a</jats:italic> &gt; 150 au, <jats:italic>q</jats:italic> &gt; 30 au) are consistent with the null hypothesis of azimuthal isotropy; and nonresonant TNOs with <jats:italic>q</jats:italic> &gt; 38 au, <jats:italic>a</jats:italic> &gt; 50 au show a significant tendency to be sunward of major mean-motion resonances.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>SPT-3G is the third survey receiver operating on the South Pole Telescope dedicated to high-resolution observations of the cosmic microwave background (CMB). Sensitive measurements of the temperature and polarization anisotropies of the CMB provide a powerful data set for constraining cosmology. Additionally, CMB surveys with arcminute-scale resolution are capable of detecting galaxy clusters, millimeter-wave bright galaxies, and a variety of transient phenomena. The SPT-3G instrument provides a significant improvement in mapping speed over its predecessors, SPT-SZ and SPTpol. The broadband optics design of the instrument achieves a 430 mm diameter image plane across observing bands of 95, 150, and 220 GHz, with 1.2′ FWHM beam response at 150 GHz. In the receiver, this image plane is populated with 2690 dual-polarization, trichroic pixels (∼16,000 detectors) read out using a 68× digital frequency-domain multiplexing readout system. In 2018, SPT-3G began a multiyear survey of 1500 deg<jats:sup>2</jats:sup> of the southern sky. We summarize the unique optical, cryogenic, detector, and readout technologies employed in SPT-3G, and we report on the integrated performance of the instrument.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We combine LAMOST DR7 spectroscopic data and Gaia EDR3 photometric data to construct high-quality giant (0.7 &lt; (BP − RP) &lt; 1.4) and dwarf (0.5 &lt; (BP − RP) &lt; 1.5) samples in the high Galactic latitude region, with precise corrections for magnitude-dependent systematic errors in the Gaia photometry and careful reddening corrections using empirically determined color- and reddening-dependent coefficients. We use the two samples to build metallicity-dependent stellar loci of Gaia colors for giants and dwarfs, respectively. For a given (BP − RP) color, a 1 dex change in [Fe/H] results in about a 5 mmag change in (BP − <jats:italic>G</jats:italic>) color for solar-type stars. These relations are used to determine metallicity estimates from EDR3 colors. Despite the weak sensitivity, the exquisite data quality of these colors enables a typical precision of about <jats:italic>δ</jats:italic> [Fe/H] = 0.2 dex. Our method is valid for FGK stars with <jats:italic>G</jats:italic> ≤ 16, [Fe/H] ≥ −2.5, and <jats:italic>E</jats:italic>(<jats:italic>B</jats:italic> − <jats:italic>V</jats:italic>) ≤ 0.5. Stars with fainter <jats:italic>G</jats:italic> magnitudes, lower metallicities, or larger reddening suffer from higher metallicity uncertainties. With the enormous data volume of Gaia, we have measured metallicity estimates for about 27 million stars with 10 &lt; <jats:italic>G</jats:italic> ≤ 16 across almost the entire sky, including over 6 million giants and 20 million dwarfs, which can be used for a number of studies. These include investigations of Galactic formation and evolution, the identification of candidate stars for subsequent high-resolution spectroscopic follow-up, the identification of wide binaries, and to obtain metallicity estimates of stars for asteroseismology and exoplanet research.</jats:p>