Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>Recoiling active galactic nuclei (AGNs) can be formed after the merging of two galaxies and their central supermassive black holes. A novel method recently revealed a handful of recoiling AGN candidates. We report on the arcsec-scale radio structure of one of them, 4C 18.47, a prominent radio emitter. We also present its infrared light curve, indicating significant long-term variability.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>For several years we have been running an “astro-animation” class (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://AstroAnimation.org" xlink:type="simple">AstroAnimation.org</jats:ext-link>) at the Maryland Institute College of Art (MICA) in Baltimore where students work in tandem with research scientists from NASA Goddard and elsewhere to create animations. These combine results of cutting-edge research with an artist’s eye to create novel presentations of scientific results. The animations have been used for scientific outreach and educational purposes, including presentations at museums, and art, STEAM, and science fiction festivals. Astronomy has broad public interest with a “wow” factor related to black holes, dark matter, life in the universe and more. Animation is an ideal medium since it combines creative approaches, is highly popular, and the films produced are readily available for distribution.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present infrared spectroscopy from two epochs of V1533 Scorpii (=Nova Scorpii 2013); one from immediately before dust formation and a second, from one month later when dust formation was complete. The pre-dust spectrum shows strong lines of C <jats:sc>i</jats:sc>, features that weakened considerably but were still present after dust formation. Also present in the post-formation spectrum was O <jats:sc>i</jats:sc> emission from the neutral region, indicating that dust formation did not full deplete either carbon or oxygen. While thermal emission from the dust, of a temperature very close to 870 K, dominated the later spectrum, the extinction did not change measurably between epochs, indicating that little or no dust blocked the line-of-sight. Although carbon monoxide was not detected in the first epoch spectrum, weak emission from molecular hydrogen may have been present.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Type IIn supernovae (SNe IIn) are an enigmatic subclass of SNe that show heterogeneity in their photometric and spectroscopic properties. Complex, multi-component Balmer line profiles are a defining property of SNe IIn. Perhaps owing to the heterogeneity in the SN IIn class, online databases often conflict and hold outdated or erroneous classifications. This is compounded by SN “impostors” and H <jats:sc>ii</jats:sc> region contamination. We outline a classification scheme based on multi-component H<jats:italic>α</jats:italic> profiles and apply it to a sample of 115 nearby (redshift <jats:italic>z</jats:italic> &lt; 0.02) SNe that have held a SN IIn classification on the Open Supernova Catalogue (OSC). We find that 25 of our transients were misclassified as SNe IIn. We also note that there is disagreement between OSC and the Transient Name Server for 51 of the transients.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Ly<jats:italic>α</jats:italic> photons from the first radiating sources in the universe play a pivotal role in 21 cm radio detections of Cosmic Dawn and the Epoch of Reionization. Comments are provided on the effect of the hyperfine structure of hydrogen on the rate of heating or cooling of the Intergalactic Medium by Ly<jats:italic>α</jats:italic> photons.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We re-examine the XUV luminosity evolution of TRAPPIST-1 utilizing new observational constraints (XUV and bolometric luminosity) from multi-epoch X-ray/UV photometry. Following the formalism presented in Fleming et al., we infer that TRAPPIST-1 maintained a saturated XUV luminosity, relative to the bolometric luminosity, of log<jats:sub>10</jats:sub>(<jats:italic>L</jats:italic> <jats:sub>XUV</jats:sub>/<jats:italic>L</jats:italic> <jats:sub>bol</jats:sub>) <jats:inline-formula> <jats:tex-math> <?CDATA $=-{3.03}_{-0.23}^{+0.25}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>3.03</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.23</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.25</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac034cieqn1.gif" xlink:type="simple" /> </jats:inline-formula> at early times for a period of <jats:italic>t</jats:italic> <jats:sub>sat</jats:sub> <jats:inline-formula> <jats:tex-math> <?CDATA $={3.14}_{-1.46}^{+2.22}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>3.14</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1.46</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>2.22</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac034cieqn2.gif" xlink:type="simple" /> </jats:inline-formula> Gyr. After the saturation phase, we find <jats:italic>L</jats:italic> <jats:sub>XUV</jats:sub> decayed over time by an exponential rate of <jats:italic>β</jats:italic> <jats:sub>XUV</jats:sub> <jats:inline-formula> <jats:tex-math> <?CDATA $=-{1.17}_{-0.28}^{+0.27}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>1.17</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.28</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.27</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac034cieqn3.gif" xlink:type="simple" /> </jats:inline-formula>. Compared to our inferred age of the system, <jats:inline-formula> <jats:tex-math> <?CDATA $\mathrm{age}={7.96}_{-1.87}^{+1.78}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>age</mml:mi> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>7.96</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1.87</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>1.78</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac034cieqn4.gif" xlink:type="simple" /> </jats:inline-formula> Gyr, our result for <jats:italic>t</jats:italic> <jats:sub>sat</jats:sub> suggests that there is only a ∼4% chance that TRAPPIST-1 still remains in the saturated phase today, which is significantly lower than the previous estimate of 40%. Despite this reduction in <jats:italic>t</jats:italic> <jats:sub>sat</jats:sub>, our results remain consistent in the conclusion that the TRAPPIST-1 planets likely received an extreme amount XUV energy—an estimated integrated XUV energy of ∼10<jats:sup>30</jats:sup>–10<jats:sup>32</jats:sup> erg over the star’s lifetime.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>This study aims to contribute to the astronomical studies for the creation of the astronomical and archaeological museum in Ecuador. Coaque, a fishermen village in the north coastal of Ecuador, is an iconic place where astronomy and archeology converge and portrays the geodesic and astronomical history of Ecuador. The 16th Century ethnohistorical data is rich on descriptions about abundance of wealth and land fertility within equinoctial zones. This awoke the curiosity of Europeans on the geodesic position. Two centuries later, La Condamine and Bouguer of the French-Hispanic Geodesic Mission, first measured the zero-degrees latitude at Punta Palmar, just south of Coaque. We present the detectability of the Crab Nebula, a high energy TeV source revealing the potential for astroparticles field of study. Also, we clarified the wrong idea of the equilibrium of an egg at zero latitude, a popular misinterpreted physical phenomenon.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We summarize results of an XMM-Newton X-ray observation of the WN8h-type Wolf–Rayet star WR 66 which shows unusual 3.5–4.1 hr optical variations. One possible explanation is a compact companion (cc) which, if present, could give rise to luminous X-ray emission. WR 66 was marginally detected and its inferred X-ray luminosity (<jats:italic>L</jats:italic> <jats:sub> <jats:italic>x</jats:italic> </jats:sub>) is orders of magnitude below that expected from wind accretion onto a neutron star, but is comparable to that of the WN8h stars WR 16 and WR 124. If luminous X-ray emission from an accreting WR+cc system is present then it is absorbed and escapes detection. Other explanations of the faintly detected X-ray emission of WN8h stars are not ruled out.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Population synthesis studies of binary black hole mergers often lack robust black hole spin estimates as they cannot accurately follow tidal spin-up during the late black hole–Wolf–Rayet evolutionary phase. We provide an analytical approximation of the dimensionless second-born black hole spin given the binary orbital period and Wolf–Rayet stellar mass at helium depletion or carbon depletion. These approximations are obtained from fitting a sample of around 10<jats:sup>5</jats:sup> detailed MESA simulations that follow the evolution and spin up of close black hole–Wolf–Rayet systems with metallicities in the range <jats:inline-formula> <jats:tex-math> <?CDATA $[{10}^{-4},1.5\ {Z}_{\odot }]$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo stretchy="true">[</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> <mml:mo>,</mml:mo> <mml:mn>1.5</mml:mn> <mml:mspace width="0.33em" /> <mml:msub> <mml:mrow> <mml:mi>Z</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> <mml:mo stretchy="true">]</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac053cieqn1.gif" xlink:type="simple" /> </jats:inline-formula>. Following the potential spin up of the Wolf–Rayet progenitor, the second-born black hole spin is calculated using up-to-date core collapse prescriptions that account for any potential disk formation in the collapsing Wolf–Rayet star. The fits for second-born black hole spin provided in this work can be readily applied to any astrophysical modeling that relies on rapid population synthesis, and will be useful for the interpretation of gravitational-wave sources using such models.</jats:p>