Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>The Odd Radio Circles are newly identified diffuse radio sources at ∼1 GHz frequency, with edge-brightened nearly circular morphology, which is remarkably similar to supernova remnants although a physical association with previous population of Galactic supernova remnants is challenging due to detections of the Odd Radio Circles at high Galactic latitudes. Here, a serendipitous identification of a new source in a LOFAR 144 MHz image with similar morphology as that of Odd Radio Circles is reported. This is the first reported identification of an Odd Radio Circle at a very low frequency and with the LOFAR.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>An attractive interpretation of MOdified Newtonian Dynamics as an alternative to dark matter, changes the inertia of matter at accelerations <jats:italic>a</jats:italic> ≲ <jats:italic>a</jats:italic> <jats:sub>0</jats:sub> ≈ 1.2 × 10<jats:sup>−8</jats:sup> cm s<jats:sup>−2</jats:sup>. I show that if inertia is modified at low accelerations, this suppresses the exponential factor for the required fuel mass in low acceleration journeys. Rockets operating at <jats:italic>a</jats:italic> ≪ <jats:italic>a</jats:italic> <jats:sub>0</jats:sub> might allow intergalactic travel with a modest fuel-to-payload mass ratio.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The early use of the term <jats:italic>supergiant</jats:italic> within the published literature has been traced from text searches carried out with the SAO/NASA Astrophysics Data System.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>RS Oph has persistently displayed flickering at optical wavelengths when observed away from its repeating nova outbursts. During the 2006 eruption the flickering disappeared, and this repeated during the recent 2021 event. We have been monitoring RS Oph looking for the reappearance of flickering at <jats:italic>B</jats:italic>-band following the 2021 outburst. The flickering was still absent (<jats:italic>σ</jats:italic>(<jats:italic>B</jats:italic>) &lt; 0.002 mag) on day +210 (counted from nova optical maximum), appeared at <jats:italic>σ</jats:italic>(<jats:italic>B</jats:italic>) = 0.008 mag on day +224, and raised to <jats:italic>σ</jats:italic>(<jats:italic>B</jats:italic>) = 0.029 mag on day +250. On following dates the amplitude remained large, although fluctuating. The recovery of <jats:italic>B</jats:italic>-band quiescence brightness by RS Oph begun around day +225 and was completed by day +260. The parallel patterns followed by the rise in system brightness and the reappearance of flickering confirm the central role played in RS Oph by the return to pre-outburst conditions of the accretion disk and the refilling by the RG wind of the immediate circumstellar space.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>I show that interstellar films of material thinner than a micron, drift away from the Galactic plane as a result of stellar radiation pressure. Such films, whether produced naturally by dust coagulation in proto-planetary disks or artificially by technological civilizations, would accumulate over the age of the Milky Way and hover above the Galactic disk at a scale-height set gravitationally by the dark matter halo. Limits on scattered starlight imply that this population carries a fraction below 2 × 10<jats:sup>−3</jats:sup> of the interstellar medium mass.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The analysis of twelve high resolution SWP spectra of the HgMn star HD 143807 A (<jats:italic>ι</jats:italic> CrB A) obtained through the large aperture recorded by the International Ultraviolet Explorer reveals that the far-ultraviolet flux of this star remained constant over the various observations with IUE. The TESS lightcurve of <jats:italic>ι</jats:italic> CrB does not show evidence for periodic variability. The absence of far and mid-UV variability and the reproducibility of the brightness in the <jats:italic>V</jats:italic> band during the IUE observations precludes the presence of large chemical gradients over the surface of <jats:italic>ι</jats:italic> CrB at the epoch of the IUE observations. The analysis of six high resolution SOPHIE spectra obtained over three consecutive nights in 2007 March does not show any variations of the lines, either in reduced intensity nor in radial velocity.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Several recent works have tested fundamental physics with horizon-scale black hole (BH) images, using the size <jats:italic>r</jats:italic> <jats:sub>sh</jats:sub> and deviation from circularity <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}{ \mathcal C }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mi mathvariant="italic"></mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac7331ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> of the BH shadow. For the Event Horizon Telescope image of Sgr A*, limits on <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}{ \mathcal C }$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mi mathvariant="italic"></mml:mi> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac7331ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> are not available due to the sparse interferometric coverage of the 2017 observations, alongside the short variability timescale of Sgr A* compared to M87*. We comment on the results of a recent preprint which purports to have derived new limits on extra dimensions using the deviation from circularity of Sgr A*'s shadow. The latter is quoted to be ≲10% as with M87*, based on the “similarity” of the two shadows, which however is an incorrect assumption. In the immediate future, the simplest tests of fundamental physics from Sgr A*'s image will mostly have to rely on <jats:italic>r</jats:italic> <jats:sub>sh</jats:sub>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Massive pulsating white dwarf stars are extremely rare, because they are the final product of intermediate-mass stars, which are less common than low-mass stars. Additionally, their small size makes them fainter than the normal-mass white dwarf stars (∼0.6 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>). Our motivation to look for this type of variable is to be able to study in detail their internal structure and therefore derive properties for the outcome of the evolution of intermediate mass stars, below 10 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>. Using the 2.1 m Otto Struve Telescope at McDonald Observatory, we report on the discovery of a new massive pulsating white dwarf star. These stars might be massive enough that their cores have a significant crystallized portion, up to about 50%. A detailed asteroseismic study of these stars will provide important constrains on intermediate-mass stellar evolution, and the opportunity to study solid state physics at extreme conditions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We compute the optimal divider between the red sequence and blue sequence in the Sloan Digital Sky Survey Legacy Survey of galaxies. Within the luminosity range −18 &gt; <jats:italic>M</jats:italic> <jats:sub> <jats:italic>r</jats:italic> </jats:sub> &gt; −24, we find a good fit with a simple linear relation, <jats:italic>u</jats:italic> − <jats:italic>r</jats:italic> = 2.326–0.1305(<jats:italic>M</jats:italic> <jats:sub> <jats:italic>r</jats:italic> </jats:sub> + 21).</jats:p>

<jats:title>Abstract</jats:title> <jats:p>V<jats:sc>ideo</jats:sc> is a deep near-infrared survey which targets 12deg2 over the ELAIS-S1 (2 continuous V<jats:sc>ircam</jats:sc> tiles), XMM-LSS, and E-CDFS (3 continuous V<jats:sc>ircam</jats:sc> tiles, each) extra-galactic fields. This research note presents the final data release (DR5) of all tiles, stacks and the deep stacked data in all areas, V<jats:sc>ideo</jats:sc>-ES1, V<jats:sc>ideo</jats:sc>-XMM and V<jats:sc>ideo</jats:sc>-CDFS in <jats:italic>Z</jats:italic>, <jats:italic>Y</jats:italic>, <jats:italic>J</jats:italic>, <jats:italic>H</jats:italic> and <jats:italic>Ks</jats:italic> bands.</jats:p>