Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>We examine the correlations of star formation rate (SFR) and gas-phase metallicity <jats:italic>Z</jats:italic>. We first predict how the SFR, cold gas mass, and <jats:italic>Z</jats:italic> will change with variations in inflow rate or in star formation efficiency (SFE) in a simple gas-regulator framework. The changes <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> SFR and <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}Z$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> are found to be negatively (positively) correlated when driving the gas regulator with time-varying inflow rate (SFE). We then study the correlation of <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> sSFR (specific SFR) and <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn4.gif" xlink:type="simple" /> </jats:inline-formula>(O/H) from observations, at both ∼100 pc and galactic scales, based on two two-dimensional spectroscopic surveys with different spatial resolutions, MAD and MaNGA. After taking out the overall mass and radial dependences, which may reflect changes in inflow gas metallicity and/or outflow mass loading, we find that <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn5.gif" xlink:type="simple" /> </jats:inline-formula> sSFR and <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn6.gif" xlink:type="simple" /> </jats:inline-formula>(O/H) on galactic scales are found to be negatively correlated, but <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn7.gif" xlink:type="simple" /> </jats:inline-formula> sSFR and <jats:inline-formula> <jats:tex-math> <?CDATA ${\rm{\Delta }}\mathrm{log}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabe413ieqn8.gif" xlink:type="simple" /> </jats:inline-formula>(O/H) are positively correlated on ∼100 pc scales within galaxies. If we assume that the variations across the population reflect temporal variations in individual objects, we conclude that variations in the SFR are primarily driven by time-varying inflow at galactic scales and driven by time-varying SFE at ∼100 pc scales. We build a theoretical framework to understand the correlation between SFR, gas mass, and metallicity, as well as their variability, which potentially uncovers the relevant physical processes of star formation at different scales.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The projected stellar rotational velocity (<jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>) is critical for our understanding of processes related to the evolution of angular momentum in pre-main-sequence stars. We present <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> measurements of high-resolution infrared and optical spectroscopy for 70 pre-main-sequence stars in the Taurus–Auriga star-forming region, in addition to effective temperatures measured from line-depth ratios, as well as stellar rotation periods determined from optical photometry. From the literature, we identified the stars in our sample that show evidence of residing in circumstellar disks or multiple systems. The comparison of infrared <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> measurements calculated using two techniques shows a residual scatter of ∼1.8 km s<jats:sup>−1</jats:sup>, defining a typical error floor for the <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn4.gif" xlink:type="simple" /> </jats:inline-formula> of pre-main-sequence stars from infrared spectra. A comparison of the <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn5.gif" xlink:type="simple" /> </jats:inline-formula> distributions of stars with and without companions shows that binaries/multiples typically have a higher measured <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn6.gif" xlink:type="simple" /> </jats:inline-formula>, which may be caused by contamination by companion lines, shorter disk lifetimes in binary systems, or tidal interactions in hierarchical triples. A comparison of optical and infrared <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn7.gif" xlink:type="simple" /> </jats:inline-formula> values shows no significant difference regardless of whether the star has a disk or not, indicating that CO contamination from the disk does not impact <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn8.gif" xlink:type="simple" /> </jats:inline-formula> measurements above the typical ∼1.8 km s<jats:sup>−1</jats:sup> error floor of our measurements. Finally, we observe a lack of a correlation between the <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin i$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabeab3ieqn9.gif" xlink:type="simple" /> </jats:inline-formula>, presence of a disk, and H-R diagram position, which indicates a complex interplay between stellar rotation and evolution of pre-main-sequence stars.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Galactic black hole candidate <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="object" xlink:href="GX 339-4" xlink:type="simple">GX 339-4</jats:named-content> underwent several outbursting phases in the past two and a half decades at irregular intervals of 2–3 years. The nature of these outbursts in terms of the duration, number of peaks, maximum peak intensity, and so on varies. We present a possible physical reason behind the variation of the outbursts. From a physical point of view, if the supply of matter from the companion is roughly constant, the total energy released in an outburst is expected to be proportional to the quiescent period prior to the outburst when the matter is accumulated. We use archival data of RXTE/ASM from 1996 January to 2011 June and of MAXI/GSC from 2009 August to 2020 July. Five initial outbursts of GX 339-4 between 1997 and 2011 were observed by ASM and showed a good linear relation between the accumulation period and the amount of energy released in each outburst, but the outbursts after 2013 behaved quite differently. The 2013, 2017–2018, and 2018–2019 outbursts were of short duration and incomplete or “failed” in nature. We suggest that the matter accumulated during the quiescent periods prior to these outbursts was not cleared through accretion due to a lack of viscosity. The leftover matter was cleared in the very next outbursts. Our study thus sheds light on long-term accretion dynamics in outbursting sources.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present an extinction map of the inner ∼15′ by 16′ of the Galactic center (GC) with map pixels measuring 5″ × 5″ using integrated light color measurements in the near- and mid-infrared. We use a variant of the Rayleigh–Jeans color excess (RJCE) method first described by Majewski et al. as the basis of our work, although we have approached our problem with a Bayesian mindset and dispensed with point-source photometry in favor of surface photometry, turning the challenge of the extremely crowded field at the GC into an advantage. Our results show that extinction at the GC is not inconsistent with a single power-law coefficient, <jats:italic>β</jats:italic> = 2.03 ± 0.06, and compare our results with those using the red clump (RC) point-source photometry method of extinction estimation. We find that our measurement of <jats:italic>β</jats:italic> and its apparent lack of spatial variation are in agreement with prior studies, despite the bimodal distribution of values in our extinction map at the GC with peaks at 5 and 7.5 mag. This bimodal nature of extinction is likely due to the infrared dark clouds that obscure portions of the inner GC field. We present our extinction law and map of the GC region using the point-source catalog of infrared sources compiled by DeWitt et al. The dereddening is limited by the error in the extinction measurement (typically 0.6 mag), which is affected by the size of our map pixels and is not fine-grained enough to separate out the multiple stellar populations present toward the GC.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Outflows of ionized gas driven by active galactic nuclei (AGN) may significantly impact the evolution of their host galaxies. However, determining the energetics of these outflows is difficult with spatially unresolved observations that are subject to strong global selection effects. We present part of an ongoing study using Hubble Space Telescope and Apache Point Observatory spectroscopy and imaging to derive spatially resolved mass outflow rates and energetics for narrow-line region outflows in nearby AGN that are based on multi-component photoionization models to account for spatial variations in gas ionization, density, abundances, and dust content. This expanded analysis adds Mrk 3, Mrk 78, and NGC 1068, doubling our earlier sample. We find that the outflows contain total ionized gas masses of <jats:italic>M</jats:italic> ≈ 10<jats:sup>5.5</jats:sup>–10<jats:sup>7.5</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> and reach peak velocities of <jats:italic>v</jats:italic> ≈ 800–2000 km s<jats:sup>−1</jats:sup>. The outflows reach maximum mass outflow rates of <jats:inline-formula> <jats:tex-math> <?CDATA ${\dot{M}}_{\mathrm{out}}\approx 3\mbox{--}12\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabdcadieqn1.gif" xlink:type="simple" /> </jats:inline-formula> yr<jats:sup>−1</jats:sup> and encompass total kinetic energies of <jats:italic>E</jats:italic> ≈ 10<jats:sup>54</jats:sup>–10<jats:sup>56</jats:sup> erg. The outflows extend to radial distances of <jats:italic>r</jats:italic> ≈ 0.1–3 kpc from the nucleus, with the gas masses, outflow energetics, and radial extents positively correlated with AGN luminosity. The outflow rates are consistent with in situ ionization and acceleration where gas is radiatively driven at multiple radii. These radial variations indicate that spatially resolved observations are essential for localizing AGN feedback and determining the most accurate outflow parameters.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Planetesimals are believed to be formed by the coagulation of dust grains in the protoplanetary disk turbulence. However, the bouncing and fragmentation barriers have not been completely solved, particularly for silicate dust. To circumvent these barriers, the turbulent clustering of dust particles must be properly treated. According to the minimum-mass solar nebula (MMSN) model, the Mach number of the turbulence ranges from <jats:italic>M</jats:italic> <jats:sub>rms</jats:sub> ≃ 0.01–0.32, and thus the turbulence is often regarded as essentially incompressible. However, it has not been quantitatively investigated whether the incompressible limit is adequate for protoplanetary disk simulations. We therefore compare in this study the motions of inertial particles in direct numerical simulations (DNSs) of the Navier–Stokes equation between weakly compressible turbulence and incompressible turbulence. In the DNSs of compressible turbulence, we use an external force to set the total dissipation and the dilatational-to-solenoidal dissipation ratio. The DNSs reveal that despite the small Mach number <jats:italic>M</jats:italic> <jats:sub>rms</jats:sub>( ≲ 0.3), the compressible turbulence field notably differs from the incompressible field in terms of the density fluctuations, pressure fluctuations, and shocklet generation, depending on the ratio of the dilatational forcing. However, we quantitatively confirmed that these effects on the particle collision statistics are weak and that the motion of inertial particles in weakly compressible turbulence is dominated by the solenoidal velocity components. Therefore we can conclude that the incompressible assumption is appropriate for an investigation of the dust coagulation process in protoplanetary disk turbulence, as assumed in the MMSN model.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The anomalous diffusion of resonant protons in parallel and perpendicular velocity space by kinetic Alfvén waves is discussed. The velocity diffusion coefficient is calculated by employing an autocorrelation function for proton trajectories. It is found that for protons resonant with the waves, the perpendicular diffusion coefficient decays away for a sufficiently long time, but parallel diffusion monotonically increases in time until it saturates at a certain level. This result indicates that a portion of resonant protons can undergo anomalous diffusion along the background magnetic field even if the intensity of the kinetic Alfvén wave is sufficiently low. The present findings imply that under suitable conditions, astrophysical charged-particle acceleration can take place in the parallel direction.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We explore the kinematics of 27 <jats:italic>z</jats:italic> ≳ 6 quasar host galaxies observed in [C <jats:sc>ii</jats:sc>] 158 <jats:italic>μ</jats:italic>m ([C <jats:sc>ii</jats:sc>]) emission with the Atacama Large Millimeter/submillimeter Array at a resolution of ≈025. We find that nine of the galaxies show disturbed [C <jats:sc>ii</jats:sc>] emission, due to either a close companion galaxy or a recent merger. Ten galaxies have smooth velocity gradients consistent with the emission arising from a gaseous disk. The remaining eight quasar host galaxies show no velocity gradient, suggesting that the gas in these systems is dispersion dominated. All galaxies show high velocity dispersions with a mean of 129 ± 10 km s<jats:sup>−1</jats:sup>. To provide an estimate of the dynamical mass within twice the half-light radius of the quasar host galaxy, we model the kinematics of the [C <jats:sc>ii</jats:sc>] emission line using our publicly available kinematic fitting code, <jats:monospace>qubefit</jats:monospace>. This results in a mean dynamical mass of 5.0 ± 0.8( ± 3.5) × 10<jats:sup>10</jats:sup> <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>. Comparison between the dynamical mass and the mass of the supermassive black hole reveals that the sample falls above the locally derived bulge mass–black hole mass relation at 2.4<jats:italic>σ</jats:italic> significance. This result is robust even if we account for the large systematic uncertainties. Using several different estimators for the molecular mass, we estimate a gas mass fraction of &gt;10%, indicating that gas makes up a large fraction of the baryonic mass of <jats:italic>z</jats:italic> ≳ 6 quasar host galaxies. Finally, we speculate that the large variety in [C <jats:sc>ii</jats:sc>] kinematics is an indication that gas accretion onto <jats:italic>z</jats:italic> ≳ 6 supermassive black holes is not caused by a single precipitating factor.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We have analyzed ALMA Cycle 5 data in Band 4 toward three low-mass young stellar objects, IRAS 03235+3004 (hereafter IRAS 03235), IRAS 03245+3002 (IRAS 03245), and IRAS 03271+3013 (IRAS 03271), in the Perseus region. The HC<jats:sub>3</jats:sub>N (<jats:italic>J</jats:italic> = 16–15; <jats:italic>E</jats:italic> <jats:sub>up</jats:sub>/<jats:italic>k</jats:italic> = 59.4 K) line has been detected in all of the target sources, while four CH<jats:sub>3</jats:sub>OH lines (<jats:italic>E</jats:italic> <jats:sub>up</jats:sub>/<jats:italic>k</jats:italic> = 15.4–36.3 K) have been detected only in IRAS 03245. Sizes of the HC<jats:sub>3</jats:sub>N distributions (∼2930–3230 au) in IRAS 03235 and IRAS 03245 are similar to those of the carbon-chain species in the warm carbon-chain chemistry (WCCC) source L1527. The size of the CH<jats:sub>3</jats:sub>OH emission in IRAS 03245 is ∼1760 au, which is slightly smaller than that of HC<jats:sub>3</jats:sub>N in this source. We compare the CH<jats:sub>3</jats:sub>OH/HC<jats:sub>3</jats:sub>N abundance ratios observed in these sources with predictions of chemical models. We confirm that the observed ratio in IRAS 03245 agrees with the modeled values at temperatures around 30–35 K, which supports the HC<jats:sub>3</jats:sub>N formation by the WCCC mechanism. In this temperature range, CH<jats:sub>3</jats:sub>OH does not thermally desorb from dust grains. Nonthermal desorption mechanisms or gas-phase formation of CH<jats:sub>3</jats:sub>OH seem to work efficiently around IRAS 03245. The fact that IRAS 03245 has the highest bolometric luminosity among the target sources seems to support these mechanisms, in particular the nonthermal desorption mechanisms.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The discovery of early bumps in some type-I superluminous supernovae (SLSNe-I) before the main peaks offers an important clue to their energy source mechanisms. In this paper, we updated an analytic magnetar-powered model for fitting the multiband light curves of double-peaked SLSNe-I. The early bump is powered by magnetar-driven shock-breakout thermal emission, and the main peak is powered by a radiative diffusion through the supernova (SN) ejecta as in the standard magnetar-powered model. Generally, the diffusive luminosity is greater than the shock-breakout luminosity at the early time, which usually makes the shock-breakout bumps unclear to observe. To obtain a clear double-peaked light curve, inefficient magnetar heating at early times is required. This model is applied to three well-observed double-peaked SLSNe-I (i.e., SN2006oz, LSQ14bdq, and DES14Xtaz). We find that a relatively massive SN ejecta with <jats:italic>M</jats:italic> <jats:sub>ej</jats:sub> ≃ 10.2–18.1<jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> and relatively large kinetic energy of SN ejecta <jats:inline-formula> <jats:tex-math> <?CDATA ${E}_{\mathrm{sn}}\simeq (3.8\mbox{--}6.5)\times {10}^{51}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabf042ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> erg are required, and the thermalization efficiency of the magnetar heating is suppressed before <jats:italic>t</jats:italic> <jats:sub>delay</jats:sub>, which is in the range of ≃15–43 days. The model can reproduce the observed light curves well, with a reasonable and similar set of physical parameters for both the early bump and the main peak, strengthening support for the magnetar-powered model. In the future, modeling of the double-peaked SLSNe-I will become more feasible as more events are discovered before the early bump.</jats:p>