High-Sensitivity 86GHz (3.5mm) VLBI Observations of M87: Deep Imaging of the Jet Base at a 10 Schwarzschild-Radius Resolution

We report on results from new high-sensitivity, high-resolution 86GHz (3.5 millimeter) observations of the jet base in the nearby radio galaxy M87, obtained by the Very Long Baseline Array in conjunction with the Green Bank Telescope. The resulting image has a dynamic range exceeding 1500 to 1, the highest ever achieved for this jet at this frequency, resolving and imaging a detailed jet formation/collimation structure down to ~10 Schwarzschild radii (Rs). The obtained 86GHz image clearly confirms some important jet features known at lower frequencies, i.e., a wide-opening angle jet base, a limb-brightened intensity profile, a parabola-shape collimation profile and a counter jet. The limb-brightened structure is already well developed at < 0.2mas (< 28Rs, projected) from the core, where the corresponding apparent opening angle becomes as wide as ~100 degrees. The subsequent jet collimation near the black hole evolves in a complicated manner; there is a "constricted" structure at tens Rs from the core, where the jet cross section is locally shrinking. We suggest that an external pressure support from the inner part of radiatively-inefficient accretion flow may be dynamically important in shaping/confining the footprint of the magnetized jet. We also present the first VLBI 86GHz polarimetric experiment for this source, where a highly polarized (~20%) feature is detected near the jet base, indicating the presence of a well-ordered magnetic field. As a by-product, we additionally report a 43/86 GHz polarimetric result for our calibrator 3C 273 suggesting an extreme rotation measure near the core.Comment: Accepted for publication in ApJ. 39 pages, 11 figures, 3 table

Parabolic Jets from the Spinning Black Hole in M87

The M87 jet is extensively examined by utilizing general relativistic magnetohydrodynamic (GRMHD) simulations as well as the steady axisymmetric force-free electrodynamic (FFE) solution. Quasi-steady funnel jets are obtained in GRMHD simulations up to the scale of $\sim 100$ gravitational radius ($r_{\rm g}$) for various black hole (BH) spins. As is known, the funnel edge is approximately determined by the following equipartitions; i) the magnetic and rest-mass energy densities and ii) the gas and magnetic pressures. Our numerical results give an additional factor that they follow the outermost parabolic streamline of the FFE solution, which is anchored to the event horizon on the equatorial plane. We also identify the matter dominated, non-relativistic corona/wind play a dynamical role in shaping the funnel jet into the parabolic geometry. We confirm a quantitative overlap between the outermost parabolic streamline of the FFE jet and the edge of jet sheath in VLBI observations at $\sim 10^{1}$-$10^{5} \, r_{\rm g}$, suggesting that the M87 jet is likely powered by the spinning BH. Our GRMHD simulations also indicate a lateral stratification of the bulk acceleration (i.e., the spine-sheath structure) as well as an emergence of knotty superluminal features. The spin characterizes the location of the jet stagnation surface inside the funnel. We suggest that the limb-brightened feature could be associated with the nature of the BH-driven jet, if the Doppler beaming is a dominant factor. Our findings can be examined with (sub-)mm VLBI observations, giving a clue for the origin of the M87 jet.Comment: 29 pages, 23 figures, accepted for publication in Ap

Parabolic Jets from the Spinning Black Hole in M87

The M87 jet is extensively examined by utilizing general relativistic magnetohydrodynamic (GRMHD) simulations, as well as the steady axisymmetric force-free electrodynamic (FFE) solution. Quasi-steady funnel jets are obtained in GRMHD simulations up to the scale of ~100 gravitational radii (r(sub g)) for various black hole (BH) spins. As is known, the funnel edge is approximately determined by the following equipartitions: (i) the magnetic and rest-mass energy densities and (ii) the gas and magnetic pressures. Our numerical results give an additional factor that they follow the outermost parabolic streamline of the FFE solution, which is anchored to the event horizon on the equatorial plane. We also show that the matter-dominated, nonrelativistic corona/wind plays a dynamical role in shaping the funnel jet into the parabolic geometry. We confirm a quantitative overlap between the outermost parabolic streamline of the FFE jet and the edge of the jet sheath in very long baseline interferometry (VLBI) observations at ~(10(exp 1)10(exp 5))r(sub g), suggesting that the M87 jet is likely powered by the spinning BH. Our GRMHD simulations also indicate a lateral stratification of the bulk acceleration (i.e., the spine-sheath structure), as well as an emergence of knotty superluminal features. The spin characterizes the location of the jet stagnation surface inside the funnel. We suggest that the limb-brightened feature could be associated with the nature of the BH-driven jet, if the Doppler beaming is a dominant factor. Our findings can be examined with (sub)millimeter VLBI observations, giving a clue for the origin of the M87 jet

Electrophysiological properties of AQP6 in mouse parotid acinar cells

Salivary gland acinar cells secrete large amounts of water and electrolytes, where aquaporins (AQPs) are thought to be involved in the secretion. In the present study, we investigated expression/localization of AQP6, and the anion transporting properties of AQP6 in mouse parotid acinar cells. RT-PCR, western blotting and immunohistochemical analyses revealed expression of AQP6 in acinar cells, localized in apical membrane. Voltage ramp from -100 mV to +100 mV at a holding potential of -60 mV elicited outwardlyrectifying currents, in the presence of extracellular Cl- channel blockers and intracellular solution with 150 mM Cs+. These outward currents were increased when extracellular Cl- was replaced by Br-, NO3-, I-, or SCN-, accompanying a negative shift of reversal potentials. The outward current was enhanced by extracellular Hg2+. These results were consistent with the biophysical properties of transfected AQP6 oocytes or HEK cells, which indicate that the AQP6 channel is functionally expressed in parotid acinar cells, and suggest that AQP6 contributes to secretion of anions in parotid acinar cells

フキノール酸のラジカル消去能について

今まで報告例のないフキノール酸(FA)のラジカル消去能について、クロロゲン酸(CGA)、エピガロカテキンガレート(EGCG)、没食子酸(GA)と比較して検討した。スーパーオキシドアニオン(HX-XOD反応で生成)、ヒドロキシルラジカル(フェントン反応で生成)、一酸化窒素(NOC-7より生成)およびDPPHラジカル消去能はESR法を用いて測定した。またDPPHラジカル消去能は吸光度法でも測定した。その結果、スーパーオキシドアニオン消去能はEGCG>GA>FA>CGAの順、ヒドロキシルラジカル消去能はEGCG>CGA>FA>GAの順、一酸化窒素消去能はEGCG>FA>CGAの順、ESR法で測定したDPPHラジカル消去能はEGCG>GA>FA>CGAの順、そして吸光度法で測定したDPPHラジカル消去能はEGCG>FA>CGAの順となった。本研究によりFAは抗酸化剤としての利用が期待できると考えられる。Radical scavenging activity of fukinolic acid (FA), chlorogenic acid (CGA), epigallocatechin gallate (EGCG) and gallic acid (GA) against superoxide anion (produced by HX-XOD reaction), hydroxyl radical (produced by Fenton reaction), nitric oxide (NO) (produced by NOC-7 with carboxy-PTIO) and DPPH radical was measured by ESR spectroscopy and OD method. The radical scavenging activity of these compounds was in the following order : (1) superoxide anion, EGCG>GA>FA>CGA, (2) hydroxyl radical, EGCG>CGA>FA>GA, (3) NO, EGCG>FA>CGA, and (4) DPPH radical, EGCG>GA>FA>CGA (ESR method), EGCG>FA>CGA (OD method). These data suggest that FA should be considered as a candidate of applicable antioxidant as well as other polyphenols