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<jats:title>Abstract</jats:title> <jats:p>Despite many decades of study, the kinematics of the broad-line region of 3C 273 are still poorly understood. We report a new, high signal-to-noise, reverberation mapping campaign carried out from 2008 November to 2018 March that allows the determination of time lags between emission lines and the variable continuum with high precision. The time lag of variations in H<jats:italic>β</jats:italic> relative to those of the 5100 Å continuum is <jats:inline-formula> <jats:tex-math> <?CDATA ${146.8}_{-12.1}^{+8.3}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1099ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> days in the rest frame, which agrees very well with the Paschen-<jats:italic>α</jats:italic> region measured by the GRAVITY at The Very Large Telescope Interferometer. The time lag of the H<jats:italic>γ</jats:italic> emission line is found to be nearly the same as that for H<jats:italic>β</jats:italic>. The lag of the Fe <jats:sc>ii</jats:sc> emission is <jats:inline-formula> <jats:tex-math> <?CDATA ${322.0}_{-57.9}^{+55.5}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1099ieqn2.gif" xlink:type="simple" /> </jats:inline-formula> days, longer by a factor of ∼2 than that of the Balmer lines. The velocity-resolved lag measurements of the H<jats:italic>β</jats:italic> line show a complex structure that can be possibly explained by a rotation-dominated disk with some inflowing radial velocity in the H<jats:italic>β</jats:italic>-emitting region. Taking the virial factor of <jats:italic>f</jats:italic> <jats:sub>BLR</jats:sub> = 1.3, we derive a BH mass of <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\bullet }={4.1}_{-0.4}^{+0.3}\times {10}^{8}\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1099ieqn3.gif" xlink:type="simple" /> </jats:inline-formula> and an accretion rate of <jats:inline-formula> <jats:tex-math> <?CDATA $9.3\,{L}_{\mathrm{Edd}}\,{c}^{-2}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1099ieqn4.gif" xlink:type="simple" /> </jats:inline-formula> from the H<jats:italic>β</jats:italic> line. The decomposition of its <jats:italic>Hubble Space Telescope</jats:italic> images yields a host stellar mass of <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{* }={10}^{11.3\pm 0.7}\,{M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1099ieqn5.gif" xlink:type="simple" /> </jats:inline-formula>, and a ratio of <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\bullet }/{M}_{* }\approx 2.0\times {10}^{-3}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjab1099ieqn6.gif" xlink:type="simple" /> </jats:inline-formula> in agreement with the Magorrian relation. In the near future, it is expected to compare the geometrically thick BLR discovered by the GRAVITY in 3C 273 with its spatially resolved torus in order to understand the potential connection between the BLR and the torus.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The emergence of active regions (ARs) leads to various dynamic activities. Using high-resolution and long-lasting H<jats:italic>α</jats:italic> observations from the New Vacuum Solar Telescope, we report the dynamics of NOAA AR 12700 in its emerging phase on 2018 February 26 in detail. In this AR, constant interchange reconnections (IRs) between emerging fibrils and preexisting ones were detected. Driven by the flux emergence, small-scale fibrils observed in H<jats:italic>α</jats:italic> wavelength continuously emerged at the center of the AR and reconnected with the ambient preexisting fibrils, forming new longer fibrils. We investigate three IR scenarios that occurred over two hours. Specially, the third scenario of reconnection resulted in the formation of longer fibrils that show pronounced rotation motion. To derive the evolution of the magnetic structure during the reconnections, we perform nonlinear force-free field extrapolations. The extrapolated three-dimensional magnetic fields clearly depict a set of almost potential emerging loops, two preexisting flux ropes at 03:00 UT before the second reconnection scenario, and a set of newly formed loops with less twist at 03:48 UT after the third reconnection scenario. All of these extrapolated structures are consistent with the fibrils detected at the H<jats:italic>α</jats:italic> wavelength. The aforementioned observations and extrapolation results suggest that the constant IRs resulted in the magnetic twist being redistributed from preexisting flux ropes toward the newly formed system with longer magnetic structure and weaker twist.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present an improved determination of the Hubble constant from <jats:italic>Hubble Space Telescope (HST)</jats:italic> observations of 70 long-period Cepheids in the Large Magellanic Cloud (LMC). These were obtained with the same WFC3 photometric system used to measure extragalactic Cepheids in the hosts of SNe Ia. Gyroscopic control of <jats:italic>HST</jats:italic> was employed to reduce overheads while collecting a large sample of widely separated Cepheids. The Cepheid period–luminosity relation provides a zero-point-independent link with 0.4% precision between the new 1.2% geometric distance to the LMC from detached eclipsing binaries (DEBs) measured by Pietrzyński et al. and the luminosity of SNe Ia. Measurements and analysis of the LMC Cepheids were completed prior to knowledge of the new DEB LMC distance. Combined with a refined calibration of the count-rate linearity of WFC3-IR with 0.1% precision, these three improved elements together reduce the overall uncertainty in the geometric calibration of the Cepheid distance ladder based on the LMC from 2.5% to 1.3%. Using only the LMC DEBs to calibrate the ladder, we find <jats:italic>H</jats:italic> <jats:sub>0</jats:sub> = 74.22 ± 1.82 km s<jats:sup>−1</jats:sup> Mpc<jats:sup>−1</jats:sup> including systematic uncertainties, 3% higher than before for this particular anchor. Combining the LMC DEBs, masers in NGC 4258, and Milky Way parallaxes yields our best estimate: <jats:italic>H</jats:italic> <jats:sub>0</jats:sub> = 74.03 ± 1.42 km s<jats:sup>−1</jats:sup> Mpc<jats:sup>−1</jats:sup>, including systematics, an uncertainty of 1.91%–15% lower than our best previous result. Removing any one of these anchors changes <jats:italic>H</jats:italic> <jats:sub>0</jats:sub> by less than 0.7%. The difference between <jats:italic>H</jats:italic> <jats:sub>0</jats:sub> measured locally and the value inferred from Planck CMB and ΛCDM is 6.6 ± 1.5 km s<jats:sup>−1</jats:sup> Mpc<jats:sup>−1</jats:sup> or 4.4<jats:italic>σ</jats:italic> (<jats:italic>P</jats:italic> = 99.999% for Gaussian errors) in significance, raising the discrepancy beyond a plausible level of chance. We summarize independent tests showing that this discrepancy is not attributable to an error in any one source or measurement, increasing the odds that it results from a cosmological feature beyond ΛCDM.</jats:p>