Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>The Transiting Exoplanet Survey Satellite (TESS) exoplanet-hunting mission detected the rising and decaying optical afterglow of GRB 191016A, a long gamma-ray burst (GRB) detected by Swift-BAT but without prompt XRT or UVOT follow-up due to proximity to the Moon. The afterglow has a late peak at least 1000 s after the BAT trigger, with a brightest-detected TESS data point at 2589.7 s post-trigger. The burst was not detected by Fermi-LAT, but was detected by Fermi-GBM without triggering, possibly due to the gradual nature of the rising light curve. Using ground-based photometry, we estimate a photometric redshift of <jats:italic>z</jats:italic> <jats:sub>phot</jats:sub> = 3.29 ± 0.40. Combined with the high-energy emission and optical peak time derived from TESS, estimates of the bulk Lorentz factor Γ<jats:sub>BL</jats:sub> range from 90 to 133. The burst is relatively bright, with a peak optical magnitude in ground-based follow-up of <jats:italic>R</jats:italic> = 15.1 mag. Using published distributions of GRB afterglows and considering the TESS sensitivity and sampling, we estimate that TESS is likely to detect ∼1 GRB afterglow per year above its magnitude limit.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Source galaxy images are distorted not only by a static gravitational potential, but also by frame-dragging induced by massive rotating objects like clusters of galaxies. Such an effect is well understood theoretically; it is therefore of great interest to estimate its detectability for future surveys. In this work, we analyze the lensing convergence <jats:italic>κ</jats:italic> around rotating dark matter halos. The rotation of the massive objects generates a gravitomagnetic potential giving rise to an anisotropic contribution to the lensing potential. We construct an estimator <jats:italic>δ</jats:italic> <jats:italic>κ</jats:italic> to describe the difference between the symmetric enhancement and reduction of <jats:italic>κ</jats:italic> around the halo rotation axis, finding that it is well approximated by a function proportional to the halo velocity dispersion squared times a dimensionless angular momentum parameter. Using simulation mocks with realistic noise level for a survey like the Legacy Survey of Space and Time (LSST), we test our estimator, and show that the signal from frame-dragging of stacked rotating lenses is consistent with zero within 1<jats:italic>σ</jats:italic>. However, we find that the most massive cluster in SDSS DR7 spectroscopic selected group catalog has a line-of-sight rotation velocity of 195.0 km s<jats:sup>−1</jats:sup> and velocity dispersion of 667.8 km s<jats:sup>−1</jats:sup>, which is at 1.2 × 10<jats:sup>−8</jats:sup> odds according to the angular momentum probability distribution inferred from <jats:italic>N</jats:italic>-body simulations. By studying SDSS DR7 spectroscopic selected group catalog, we show how rotating clusters can be identified, and, finding that fast rotating clusters might be more abundant than in estimates based on simulations, a detection of gravitomagnetic distortion may be at reach in future surveys.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Over the past few decades, the measurement precision of some pulsar timing experiments has advanced from ∼10 <jats:italic>μ</jats:italic>s to ∼10 ns, revealing many subtle phenomena. Such high precision demands both careful data handling and sophisticated timing models to avoid systematic error. To achieve these goals, we present <jats:sc>PINT</jats:sc> (<jats:bold>P</jats:bold>INT <jats:bold>I</jats:bold>s <jats:bold>N</jats:bold>ot <jats:bold> <jats:sc>T</jats:sc> </jats:bold> <jats:sc>empo3</jats:sc>), a high-precision <jats:monospace>Python</jats:monospace> pulsar timing data analysis package, which is hosted on GitHub and available on the <jats:monospace>Python</jats:monospace> Package Index (PyPI) as <jats:monospace>pint-pulsar</jats:monospace>. <jats:sc>PINT</jats:sc> is well tested, validated, object oriented, and modular, enabling interactive data analysis and providing an extensible and flexible development platform for timing applications. It utilizes well-debugged public <jats:monospace>Python</jats:monospace> packages (e.g., the N<jats:sc>um</jats:sc>P<jats:sc>y</jats:sc> and A<jats:sc>stropy</jats:sc> libraries) and modern software development schemes (e.g., version control and efficient development with <jats:monospace>git</jats:monospace> and GitHub) and a continually expanding test suite for improved reliability, accuracy, and reproducibility. <jats:sc>PINT</jats:sc> is developed and implemented without referring to, copying, or transcribing the code from other traditional pulsar timing software packages (e.g., <jats:sc>Tempo</jats:sc>/<jats:sc>Tempo2</jats:sc>) and therefore provides a robust tool for cross-checking timing analyses and simulating pulse arrival times. In this paper, we describe the design, use, and validation of <jats:sc>PINT</jats:sc>, and we compare timing results between it and <jats:sc>Tempo</jats:sc> and <jats:sc>Tempo2</jats:sc>.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a multiwavelength study of galaxies around D4UD01, a spectroscopically confirmed protocluster at <jats:italic>z</jats:italic> = 3.24, to investigate environmental trends. 450 galaxies are selected based on <jats:italic>K</jats:italic> <jats:sub> <jats:italic>S</jats:italic> </jats:sub> band detection with photometric redshifts (photo-<jats:italic>z</jats:italic>) at 3.0 &lt; <jats:italic>z</jats:italic> &lt; 3.4, among which ∼12% are classified as quiescent galaxies. The quiescent galaxies are among the most massive and reddest ones in the entire sample. We identify a large photo-<jats:italic>z</jats:italic> galaxy overdensity in the field, which lies close to the previously spectroscopically confirmed sources of the protocluster. We find that the quiescent galaxies are largely concentrated in the overdense protocluster region with a higher quiescent fraction, showing a sign of environmental quenching. Galaxies in the protocluster are forming faster than their field counterparts as seen in the stellar mass function, suggesting early and accelerated mass assembly in the overdense regions. Although weak evidence of suppressed star formation is found in the protocluster, the statistics are not significant enough to draw a definite conclusion. Our work sheds light on how the formation of massive galaxies is affected in the dense region of a protocluster when the universe was only 2 Gyr old.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Interplanetary dust particles contain grains of glass with embedded metals and sulfides (GEMS; i.e., amorphous silicate grains with diameters of a few hundred nanometers containing Fe nanoinclusions and Fe sulfide particles), which are considered to be among the building blocks of the solar system. To explore that GEMS grains formed during the condensation process, condensation experiments were carried out in Si–Mg–Fe–Al–Ca–Ni–O and Mg–Si–Fe–Ca–Al–Na–O systems using an induction thermal plasma furnace. In all experimental runs, spherical grains (mostly composed of amorphous silicate) with diameter &lt;100 nm formed. The analysis of the amorphous silicates, which were classified as Mg rich or Si rich, indicated that the condensates formed via melting. Fe led to the formation of fine magnetite grains in most of the oxidative experiments, to 10 nm metal grains (i.e., kamacite and taenite) under intermediate redox conditions, and to 30–100 nm Fe silicide grains (i.e., gupeiite, xifengite, and fersilicite) in most of the reductive experiments. Under intermediate redox conditions, some amorphous silicate particles showed multiple Fe inclusions with textures very similar to those of GEMS grains except for FeS, indicating that GEMS could form via melt condensation of high-temperature gases. Considering the nucleation and growth of solids from high-temperature gas during cooling, we infer that GEMS grains form either in the local environment of a protosolar disk (and be related to chondrule formations) or around evolved stars related to Type II-P supernovae and asymptotic giant branch–type stars.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>A search for astrophysical pointlike neutrino sources using the data collected by the ANTARES detector between 2007 January 29 and 2017 December 31 is presented. A likelihood method is used to assess the significance of an excess of muon neutrinos inducing track-like events in correlation with the location of a list of possible sources. Different sets of objects are tested in the analysis: (a) a subsample of the Fermi 3LAC catalog of blazars, (b) a jet-obscured population of active galactic nuclei, (c) a sample of hard X-ray selected radio galaxies, (d) a star-forming galaxy catalog, and (e) a public sample of 56 very-high-energy track events from the IceCube experiment. None of the tested sources shows a significant association with the sample of neutrinos detected by ANTARES. The smallest <jats:italic>p</jats:italic>-value is obtained for the catalog of radio galaxies with an equal-weights hypothesis, with a pre-trial <jats:italic>p</jats:italic>-value equivalent to a 2.8<jats:italic>σ</jats:italic> excess, which is equivalent to 1.6<jats:italic>σ</jats:italic> post-trial. In addition, the results of a dedicated analysis for the blazar MG3 J225517+2409 are also reported: this source is found to be the most significant within the Fermi 3LAC sample, with five ANTARES events located less than one degree from the source. This blazar showed evidence of flaring activity in Fermi data, in spacetime coincidence with a high-energy track detected by IceCube. An a posteriori significance of 2.6<jats:italic>σ</jats:italic> for the combination of ANTARES and IceCube data is reported.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this paper, we report the first extended GeV <jats:italic>γ</jats:italic>-ray emission, at a significant level of ∼8.13<jats:italic>σ</jats:italic>, from the region of the supernova remnant SNR G317.3-0.2 by analyzing ∼12.2 yr of Fermi Large Area Telescope Pass 8 data in the work. The best-fit position of the new <jats:italic>γ</jats:italic>-ray source matches that of the 843 MHz radio energy band of SNR G317.3-0.2, and there is no significant variability of the photon flux of the corresponding light curve in the data for the 12.2 yr period. Therefore, by excluding other known <jats:italic>γ</jats:italic>-ray sources or candidates within a 2<jats:italic>σ</jats:italic> error radius from the best-fit position of SNR G317.3-0.2, we suggest that the <jats:italic>γ</jats:italic>-ray source is likely to be a GeV counterpart of SNR G317.3-0.2.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Magnetorotational instability (MRI) in complex quantum plasma, which comprises electron, ion, and dust grains, is investigated. Electrons are considered to be degenerate while ions and dust grains are taken as nondegenerate. The general dispersion relation for MRI with the effect of spin magnetization is derived using local approximations. The instability criteria for spin quantum plasma are derived using low-frequency approximations. Due to the complex nature of the dispersion relation, MHD assumptions are used to define the instability criteria. The dust mass plays a significant role in both the dispersion and growth rate of the magnetorotational mode. The complex mass of dust modifies the instability criteria. Spin magnetization force arises due to electron Pauli spin matrices and has an important role in low-temperature and highly dense plasmas that are found mainly in white dwarfs, neutron stars, and in core-collapse supernovae. It is found that spin magnetization influences the criteria for instability and hence the properties of MHD waves in the degenerate plasma.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>HO Puppis (HO Pup) was considered as a Be-star candidate based on its <jats:italic>γ</jats:italic> Cassiopeiae-type light curve, but lacked spectroscopic confirmation. Using distance measured from Gaia Data Release 2 and the spectral-energy-distribution fit on broadband photometry, the Be-star nature of HO Pup is ruled out. Furthermore, based on the 28,700 photometric data points collected from various time-domain surveys and dedicated intensive-monitoring observations, the light curves of HO Pup closely resemble those of IW And-type stars (as pointed out by Kimura et al.), exhibiting characteristics such as a quasi-standstill phase, brightening, and dips. The light curve of HO Pup displays various variability timescales, including brightening cycles ranging from 23 to 61 days, variations with periods between 3.9 days and 50 minutes during the quasi-standstill phase, and a semiregular ∼14 day period for the dip events. We have also collected time-series spectra (with various spectral resolutions), in which Balmer emission lines and other spectral lines expected for an IW And-type star were detected (even though some of these lines were also expected to be present for Be stars). We detect Bowen fluorescence near the brightening phase, and that can be used to discriminate between IW And-type stars and Be stars. Finally, despite only observing for four nights, the polarization variation was detected, indicating that HO Pup has significant intrinsic polarization.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Recent high-resolution simulations demonstrate that disks around primordial protostars easily fragment in the accretion phase before protostars accrete less than a solar mass. To understand why gravitational instability generally causes fragmentation so early, we develop a one-dimensional (1D) nonsteady model of the circumstellar disk that takes the mass supply from an accretion envelope into account. We also compare the model results to a three-dimensional (3D) numerical simulation performed with a code employing adaptive mesh refinement. Our model shows that the self-gravitating disk, through which the Toomre <jats:italic>Q</jats:italic> parameter is nearly constant at <jats:italic>Q</jats:italic> ∼ 1, gradually spreads as the disk is fed by the gas infalling from the envelope. We further find that the accretion rate onto the star is an order of magnitude smaller than the mass supply rate onto the disk. This discrepancy makes the disk more massive than the protostar in an early evolutionary stage. Most of the infalling gas is used to extend the outer part of the self-gravitating disk rather than transferred inward toward the star through the disk. We find that similar evolution also occurs in 3D simulations, where the disk becomes three times more massive than the star before the first fragmentation occurs. Our 1D disk model well explains the evolution of the disk-to-star mass ratio observed in the simulation. We argue that the formation of such a massive disk leads to early disk fragmentation.</jats:p>