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<jats:title>Abstract</jats:title> <jats:p>We report on the results of multiwavelength follow-up observations with Gemini, Very Large Array (VLA), and Australia Telescope Compact Array to search for a host galaxy and any persistent radio emission associated with FRB 180309. This FRB is among the most luminous FRB detections to date, with a luminosity of &gt;8.7 × 10<jats:sup>32</jats:sup> erg Hz<jats:sup>−1</jats:sup> at the dispersion-based redshift upper limit of 0.32. We used the high-significance detection of FRB 180309 with the Parkes Telescope and a beam model of the Parkes Multibeam Receiver to improve the localization of the FRB to a region spanning approximately <jats:inline-formula> <jats:tex-math> <?CDATA $\sim 2^{\prime} \times 2^{\prime} $?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:mn>2</mml:mn> <mml:mo accent="false">′</mml:mo> <mml:mo>×</mml:mo> <mml:mn>2</mml:mn> <mml:mo accent="false">′</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjabf6d4ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>. We aimed to seek bright galaxies within this region to determine the strongest candidates as the originator of this highly luminous FRB. We identified optical sources within the localization region above our <jats:italic>r</jats:italic>-band magnitude limit of 24.27, 14 of which have photometric redshifts whose fitted mean is consistent with the redshift upper limit (<jats:italic>z</jats:italic> &lt; 0.32) of our FRB. Two of these galaxies are coincident with marginally detected “persistent” radio sources of flux density 24.3 <jats:italic>μ</jats:italic>Jy beam<jats:sup>−1</jats:sup> and 22.1 <jats:italic>μ</jats:italic>Jy beam<jats:sup>−1</jats:sup>, respectively. Our redshift-dependent limit on the luminosity of any associated persistent radio source is comparable to the luminosity limits for other localized FRBs. We analyze several properties of the candidate hosts we identified, including chance association probability, redshift, and presence of radio emission; however, it remains possible that any of these galaxies could be the host of this FRB. Follow-up spectroscopy on these objects to explore their H<jats:italic>α</jats:italic> emission and ionization contents, as well as to obtain more precisely measured redshifts, may be able to isolate a single host for this luminous FRB.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Einstein’s theory of General Relativity predicts that the spacetime metric around astrophysical black holes is described by the Kerr solution. In this work, we employ state-of-the-art relativistic reflection modeling to analyze a selected set of NuSTAR spectra of Galactic black holes to obtain the most robust and precise constraints on the Kerr black hole hypothesis possible today. Our constraints are much more stringent than those from other electromagnetic techniques and, with some sources, we find stronger constraints than those currently available from gravitational waves.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a large statistical study of the fluctuation anisotropy in minimum variance (MV) frames of the magnetic field and solar wind velocity. We use 2, 10, 20, and 40 minute intervals of simultaneous magnetic field (the Wind spacecraft) and velocity (the Spektr-R spacecraft) observations. Our study confirms that magnetic turbulence is a composite of fluctuations varying along the mean magnetic field and those changing in the direction perpendicular to the mean field. Regardless of the length scale within the studied range of spacecraft-frame frequencies, ≈90% of the observed magnetic field fluctuations exhibit an MV direction aligned with the mean magnetic field, ≈10% of events have the MV direction perpendicular to the background field, and a negligible portion of fluctuations has no preferential direction. On the other hand, the MV direction of velocity fluctuations tends to be distributed more uniformly. An analysis of magnetic compressibility and density fluctuations suggests that the fluctuations resemble properties of Alfvénic fluctuations if the MV direction is aligned with background magnetic field whereas slow-mode-like fluctuations have the MV direction perpendicular to the background field. The proportion between Alfvénic and slow-mode-like fluctuations depends on plasma <jats:italic>β</jats:italic> and length scale: the dependence on the solar wind speed is weak. We present 3D numerical MHD simulations and show that the numerical results are compatible with our experimental results.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Several mechanisms for the transformation of blue star-forming to red quiescent galaxies have been proposed, and the green valley (GV) galaxies amid them are widely accepted in a transitional phase. Thus, comparing the morphological and environmental differences of the GV galaxies with early-type disks (ETDs; bulge dominated and having a disk) and late-type disks (LTDs; disk dominated) is suitable for distinguishing the corresponding quenching mechanisms. A large population of massive (<jats:italic>M</jats:italic> <jats:sub>*</jats:sub> ≥ 10<jats:sup>10</jats:sup> <jats:italic> M</jats:italic> <jats:sub>⊙</jats:sub>) GV galaxies at 0.5 ≤ <jats:italic>z</jats:italic> ≤ 1.5 in 3D-HST/CANDELS is selected using extinction-corrected (<jats:italic>U</jats:italic>–<jats:italic>V</jats:italic>)<jats:sub>rest</jats:sub> color. After eliminating any possible active galactic nucleus candidates and considering the “mass-matching,” we finally construct two comparable samples of GV galaxies with either 319 ETD or 319 LTD galaxies. Compared to the LTD galaxies, it is found that the ETD galaxies possess higher concentration index and lower specific star formation rate, whereas the environments surrounding them are not different. This may suggest that the morphological quenching may dominate the star formation activity of massive GV galaxies rather than the environmental quenching. To quantify the correlation between the galaxy morphology and the star formation activity, we define a dimensionless morphology quenching efficiency <jats:italic>Q</jats:italic> <jats:sub>mor</jats:sub> and find that <jats:italic>Q</jats:italic> <jats:sub>mor</jats:sub> is not sensitive to the stellar mass and redshift. When the difference between the average star formation rate of ETD and LTD galaxies is about 0.7 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup>, the probability of <jats:italic>Q</jats:italic> <jats:sub>mor</jats:sub> ≳ 0.2 is higher than 90%, which implies that the degree of morphological quenching in GV galaxies might be described by <jats:italic>Q</jats:italic> <jats:sub>mor</jats:sub> ≳ 0.2.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Infrared quasi-stellar objects (IR QSOs) are a rare subpopulation selected from ultraluminous infrared galaxies (ULIRGs) and have been regarded as promising candidates of ULIRG-to-optical QSO transition objects. Here we present NOEMA observations of the CO (1−0) line and 3 mm continuum emission in IR QSO IRAS F07599+6508 at <jats:italic>z</jats:italic> = 0.1486, which has many properties in common with Mrk 231. The CO emission is found to be resolved with a major axis of ∼6.1 kpc that is larger than the size of ∼4.0 kpc derived for 3 mm continuum. We identify two faint CO features located at a projected distance of ∼11.4 and 19.1 kpc from the galaxy nucleus, both of which are found to have counterparts in the optical and radio bands and may have a merger origin. A systematic velocity gradient is found in the CO main component, suggesting that the bulk of molecular gas is likely rotationally supported. Based on the radio-to-millimeter spectral energy distribution and IR data, we estimate that about 30% of the flux at 3 mm arises from free–free emission and infer a free–free-derived star formation rate of 77 <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup>, close to the IR estimate corrected for the AGN contribution. We find a high-velocity CO emission feature at the velocity range of about −1300 to −2000 km s<jats:sup>−1</jats:sup>. Additional deep CO observations are needed to confirm the presence of a possible very high velocity CO extension of the OH outflow in this IR QSO.</jats:p>