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<jats:title>Abstract</jats:title> <jats:p>Ultraluminous infrared galaxies (ULIRGs) have infrared luminosities <jats:italic>L</jats:italic> <jats:sub>IR</jats:sub> ≥ 10<jats:sup>12</jats:sup> <jats:italic>L</jats:italic> <jats:sub>⊙</jats:sub>, making them the most luminous objects in the infrared sky. These dusty objects are generally powered by starbursts with star formation rates that exceed 100 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup>, possibly combined with a contribution from an active galactic nucleus. Such environments make ULIRGs plausible sources of astrophysical high-energy neutrinos, which can be observed by the IceCube Neutrino Observatory at the South Pole. We present a stacking search for high-energy neutrinos from a representative sample of 75 ULIRGs with redshift <jats:italic>z</jats:italic> ≤ 0.13 using 7.5 yr of IceCube data. The results are consistent with a background-only observation, yielding upper limits on the neutrino flux from these 75 ULIRGs. For an unbroken <jats:italic>E</jats:italic> <jats:sup>−2.5</jats:sup> power-law spectrum, we report an upper limit on the stacked flux <jats:inline-formula> <jats:tex-math> <?CDATA ${{\rm{\Phi }}}_{{\nu }_{\mu }+{\bar{\nu }}_{\mu }}^{90 \% }=3.24\times {10}^{-14}\,{\mathrm{TeV}}^{-1}\,{\mathrm{cm}}^{-2}\,{{\rm{s}}}^{-1}\,{(E/10\,\mathrm{TeV})}^{-2.5}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="normal">Φ</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>μ</mml:mi> </mml:mrow> </mml:msub> <mml:mo>+</mml:mo> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mrow> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>μ</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> <mml:mrow> <mml:mn>90</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mn>3.24</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>14</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mi>TeV</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mi>cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em" /> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mi>E</mml:mi> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mn>10</mml:mn> <mml:mspace width="0.25em" /> <mml:mi>TeV</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>2.5</mml:mn> </mml:mrow> </mml:msup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac3cb6ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> at 90% confidence level. In addition, we constrain the contribution of the ULIRG source population to the observed diffuse astrophysical neutrino flux as well as model predictions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>This program is part of QUEST (Quasar/ULIRG Evolutionary Study) and seeks to examine the gaseous environments of <jats:italic>z</jats:italic> ≲ 0.3 quasars and ULIRGs as a function of host galaxy properties and age across the merger sequence from ULIRGs to quasars. This first paper in the series focuses on 33 quasars from the QUEST sample and on the kinematics of the highly ionized gas phase traced by the N <jats:sc>v</jats:sc> <jats:italic>λ</jats:italic> <jats:italic>λ</jats:italic> 1238,1243 and O <jats:sc>vi</jats:sc> <jats:italic>λ</jats:italic> <jats:italic>λ</jats:italic> 1032,1038 absorption lines in high-quality Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) data. N <jats:sc>v</jats:sc> and O <jats:sc>vi</jats:sc> outflows are present in about 60% of the QUEST quasars and span a broad range of properties, both in terms of equivalent widths (from 20 mÅ to 25 Å) and kinematics (outflow velocities from a few×100 km s<jats:sup>−1</jats:sup> up to ∼10,000 km s<jats:sup>−1</jats:sup>). The rate of incidence and equivalent widths of the highly ionized outflows are higher among X-ray weak or absorbed sources. The weighted outflow velocity dispersions are highest among the X-ray weakest sources. No significant trends are found between the weighted outflow velocities and the properties of the quasars and host galaxies, although this may be due to the limited dynamic range of properties of the current sample. These results will be re-examined in an upcoming paper where the sample is expanded to include the QUEST ULIRGs. Finally, a lower limit of ∼0.1% on the ratio of time-averaged kinetic power to bolometric luminosity is estimated in the 2–4 objects with blueshifted P <jats:sc>v</jats:sc> <jats:italic>λ</jats:italic> <jats:italic>λ</jats:italic> 1117,1128 absorption features.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>It is still unclear whether the evolution of protoplanetary disks, a key ingredient in the theory of planet formation, is driven by viscous turbulence or magnetic disk winds. As viscously evolving disks expand outward over time, the evolution of disk sizes is a discriminant test for studying disk evolution. However, it is unclear how the observed disk size changes over time if disk evolution is driven by magnetic disk winds. Combining the thermo-chemical code <jats:monospace>DALI</jats:monospace> with the analytical wind-driven disk-evolution model presented in Tabone et al., we study the time evolution of the observed gas outer radius as measured from CO rotational emission (<jats:italic>R</jats:italic> <jats:sub>CO,90%</jats:sub>). The evolution of <jats:italic>R</jats:italic> <jats:sub>CO,90%</jats:sub> is driven by the evolution of the disk mass, as the physical radius stays constant over time. For a constant <jats:italic>α</jats:italic> <jats:sub> <jats:italic>DW</jats:italic> </jats:sub>, an extension of the <jats:italic>α</jats:italic> Shakura–Sunyaev parameter to wind-driven accretion, <jats:italic>R</jats:italic> <jats:sub>CO,90%</jats:sub> decreases linearly with time. Its initial size is set by the disk mass and the characteristic radius <jats:italic>R</jats:italic> <jats:sub>c,0</jats:sub>, but only <jats:italic>R</jats:italic> <jats:sub>c,0</jats:sub> affects the evolution of <jats:italic>R</jats:italic> <jats:sub>CO,90%</jats:sub>, with a larger <jats:italic>R</jats:italic> <jats:sub>c,0</jats:sub> resulting in a steeper decrease of <jats:italic>R</jats:italic> <jats:sub>CO,90%</jats:sub>. For a time-dependent <jats:italic>α</jats:italic> <jats:sub> <jats:italic>DW</jats:italic> </jats:sub>, <jats:italic>R</jats:italic> <jats:sub>CO,90%</jats:sub> stays approximately constant during most of the disk lifetime until <jats:italic>R</jats:italic> <jats:sub>CO,90%</jats:sub> rapidly shrinks as the disk dissipates. The constant <jats:italic>α</jats:italic> <jats:sub> <jats:italic>DW</jats:italic> </jats:sub> models are able to reproduce the observed gas disk sizes in the ∼1–3 Myr old Lupus and ∼5–11 Myr old Upper Sco star-forming regions. However, they likely overpredict the gas disk size of younger (⪅0.7 Myr) disks.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The observed correlation between outer giant planets and inner super-Earths is emerging as an important constraint on planet formation theories. In this study, we focus on Kepler-167, which is currently the only system known to contain both inner transiting super-Earths and a confirmed outer transiting gas giant companion beyond 1 au. Using long-term radial velocity monitoring, we measure the mass of the gas giant Kepler-167e (<jats:italic>P</jats:italic> = 1071 days) to be <jats:inline-formula> <jats:tex-math> <?CDATA ${1.01}_{-0.15}^{+0.16}$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>1.01</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.15</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.16</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjac3ed6ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> <jats:italic>M</jats:italic> <jats:sub>J</jats:sub>, thus confirming it as a Jupiter analog. We refit the Kepler photometry to obtain updated radii for all four planets. Using a planetary structure model, we estimate that Kepler-167e contains 66 ± 19 <jats:italic>M</jats:italic> <jats:sub>⊕</jats:sub> of solids and is significantly enriched in metals relative to its solar-metallicity host star. We use these new constraints to explore the broader question of how systems like Kepler-167 form in the pebble accretion framework for giant planet core formation. We utilize simple disk evolution models to demonstrate that more massive and metal-rich disks, which are the most favorable sites for giant planet formation, can also deliver enough solids to the inner disk to form systems of super-Earths. We use these same models to constrain the nature of Kepler-167's protoplanetary disk and find that it likely contained ≳300 <jats:italic>M</jats:italic> <jats:sub>⊕</jats:sub> of dust and was ≳40 au in size. These values overlap with the upper end of the observed dust mass and size distributions of Class 0 and I disks and are also consistent with the observed occurrence rate of Jupiter analogs around Sun-like stars.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We use a sample of 27 gamma-ray bursts (GRBs) at redshift <jats:italic>z</jats:italic> = 2–6 to probe the outflows in their respective host galaxies (log(<jats:italic>M</jats:italic> <jats:sub>*</jats:sub>/<jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub>) ∼ 9–11) and search for possible relations between the outflow properties and those of the host galaxies, such as <jats:italic>M</jats:italic> <jats:sub>*</jats:sub>, the star formation rate (SFR), and the specific SFR (sSFR). First, we consider three outflow properties: outflow column density (<jats:italic>N</jats:italic> <jats:sub>out</jats:sub>), maximum outflow velocity (<jats:italic>V</jats:italic> <jats:sub>max</jats:sub>), and normalized maximum velocity (<jats:italic>V</jats:italic> <jats:sub>norm</jats:sub> = <jats:italic>V</jats:italic> <jats:sub>max</jats:sub>/<jats:italic>V</jats:italic> <jats:sub>circ,halo</jats:sub>, where <jats:italic>V</jats:italic> <jats:sub>circ,halo</jats:sub> is the halo circular velocity). We observe clear trends of <jats:italic>N</jats:italic> <jats:sub>out</jats:sub> and <jats:italic>V</jats:italic> <jats:sub>max</jats:sub> with increasing SFR in high-ion-traced outflows, with a stronger (&gt;3<jats:italic>σ</jats:italic>) <jats:italic>V</jats:italic> <jats:sub>max</jats:sub>–SFR correlation. We find that the estimated mass outflow rate and momentum flux of the high-ion outflows scale with SFR and can be supported by the momentum imparted by star formation (supernovae and stellar winds). The kinematic correlations of high-ion-traced outflows with SFR are similar to those observed for star-forming galaxies at low redshifts. The correlations with SFR are weaker in low-ion outflows. This, along with the lower detection fraction in low-ion outflows, indicates that the outflow is primarily high-ion dominated. We also observe a strong (&gt;3<jats:italic>σ</jats:italic>) trend of normalized velocity (<jats:italic>V</jats:italic> <jats:sub>norm</jats:sub>) decreasing with halo mass and increasing with sSFR, suggesting that outflows from low-mass halos and high-sSFR galaxies are most likely to escape and enrich the outer circumgalactic medium (CGM) and intergalactic medium with metals. By comparing the CGM–GRB stacks with those of starbursts at <jats:italic>z</jats:italic> ∼ 2 and <jats:italic>z</jats:italic> ∼ 0.1, we find that over a broad redshift range, the outflow strength strongly depends on the main-sequence offset at the respective redshifts, rather than simply the SFR.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Slow magnetosonic waves associated with flares were observed in coronal loops by Solar and Heliospheric Observatory/Solar Ultraviolet Measurements of Emitted Radiation, Solar Dynamics Observatory/Atmospheric Imaging Assembly in various EUV bandpasses, and other instruments. The excitation and damping of slow magnetosonic waves provides information on the magnetic, temperature, and density structure of the loops. Recently, it was found using 1.5D models that the thermal conduction is suppressed and compressive viscosity is enhanced in hot (<jats:italic>T</jats:italic> &gt; 6 MK) flaring coronal loops. We model the excitation and dissipation of slow magnetosonic waves in hot coronal loops with realistic magnetic geometry, enhanced density, and temperature (compared to background corona) guided by EUV observations using a 3D magnetohydrodynamic (MHD) visco-resistive model. The effects of the compressive viscosity tensor component along the magnetic field are included with classical and enhanced viscosity coefficient values for the first time in a 3D MHD coronal loop model. The waves are excited by a velocity pulse at the footpoint of the loop at the coronal lower boundary. The modeling results demonstrate the excitation of the slow magnetosonic waves and nonlinear coupling to other wave modes, such as the kink and fast magnetosonic. We find significant leakage of the waves from the hot coronal loops with a small effect of viscous dissipation in cooler (6 MK) loops, and more significant effects of viscous dissipation in hotter (10.5 MK) coronal loops. Our results demonstrate that nonlinear 3D MHD models are required to fully account for the various wave couplings, damping, standing wave formation, and viscous dissipation in hot flaring coronal loops. Our viscous 3D MHD code provides a new tool for improved coronal seismology.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The origin of magnetic fields in clusters of galaxies is still a matter of debate. Observations for intracluster magnetic fields over a wide range of redshifts are crucial to constrain possible scenarios for the origin and evolution of the fields. Differences in Faraday rotation measures (RMs) of an embedded double radio source, i.e., a pair of lobes of mostly Fanaroff–Riley type II radio galaxies, are free from the Faraday rotation contributions from the interstellar medium inside the Milky Way and the intergalactic medium between radio galaxies and us, and hence provide a novel way to estimate average magnetic field within galaxy clusters. We have obtained a sample of 627 pairs whose RMs and redshifts are available in the most updated RM catalogs and redshift databases. The RM differences of the pairs are derived. The statistically large RM differences for pairs of redshifts <jats:italic>z</jats:italic> &gt; 0.9 indicate that intracluster magnetic fields are as strong as about 4 <jats:italic>μ</jats:italic>G. Such strong magnetic fields in the intracluster medium at the half age of the universe, comparable to the intracluster field strength in nearby galaxy clusters, pose a challenge to the theories of the origin of cosmic magnetic fields.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Ever since the observation of peculiar overluminous Type Ia supernovae (SNeIa), exploring possible violations of the canonical Chandrasekhar mass limit (CML) has become a pressing research area of modern astrophysics. Since its first detection in 2003, more than a dozen of peculiar overluminous SNeIa has been detected, but the true nature of the underlying progenitors is still under dispute. Furthermore there are also underluminous SNeIa whose progenitor masses appear to be well below the CML (sub-Chandrasekhar progenitors). These observations call into question how sacrosanct the CML is. We have shown recently in Paper I that the presence of a strong magnetic field, the anisotropy of dense matter, as well as the orientation of the magnetic field itself significantly influence the properties of neutron and quark stars. Here, we study these effects for white dwarfs (WDs), showing that their properties are also severely impacted. Most importantly, we arrive at a variety of mass–radius relations of WDs that accommodate sub- to super-Chandrasekhar mass limits. This urges caution when using WDs associated with SNeIa as standard candles.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Wide-field near-infrared (NIR) polarimetry was used to examine disk systems around two brown dwarfs (BDs) and two young stellar objects (YSOs) embedded in the Heiles Cloud 2 (HCl2) dark molecular cloud in Taurus as well as numerous stars located behind HCl2. Inclined disks exhibit intrinsic NIR polarization due to scattering of photospheric light, which is detectable even for unresolved systems. After removing polarization contributions from magnetically aligned dust in HCl2 determined from the background star information, significant intrinsic polarization was detected from the disk systems of one BD (ITG 17) and both YSOs (ITG 15, ITG 25), but not from the other BD (2M0444). The ITG 17 BD shows good agreement of the disk orientation inferred from the NIR and from published Atacama Large Millimeter/submillieter Array dust continuum imaging. ITG 17 was also found to reside in a 5200 au wide binary (or hierarchical quad star system) with the ITG 15 YSO disk system. The inferred disk orientations from the NIR for ITG 15 and ITG 17 are parallel to each other and perpendicular to the local magnetic field direction. The multiplicity of the system and the large BD disk nature could have resulted from formation in an environment characterized by misalignment of the magnetic field and the protostellar disks.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The Gaia Alert System issued an alert on 2020 August 28, on Gaia 20eae when its light curve showed a ∼4.25 magnitude outburst. We present multiwavelength photometric and spectroscopic follow-up observations of this source since 2020 August and identify it as the newest member of the FUor/EXor family of sources. We find that the present brightening of Gaia 20eae is not due to the dust-clearing event but due to an intrinsic change in the spectral energy distribution. The light curve of Gaia 20eae shows a transition stage during which most of its brightness (∼3.4 mag) has occurred on a short timescale of 34 days with a rise rate of 3 mag/month. Gaia 20eae has now started to decay at a rate of 0.3 mag/month. We have detected a strong P Cygni profile in H<jats:italic>α</jats:italic>, which indicates the presence of winds originating from regions close to the accretion. We find signatures of very strong and turbulent outflow and accretion in Gaia 20eae during this outburst phase. We have also detected a redshifted absorption component in all of the Ca <jats:sc>ii</jats:sc> IR triplet lines consistent with a signature of hot infalling gas in the magnetospheric accretion funnel. This enables us to constrain the viewing angle with respect to the accretion funnel. Our investigation of Gaia 20eae points toward magnetospheric accretion being the phenomenon for the current outburst.</jats:p>