23 research outputs found
Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
We report the initial results of our high-cadence monitoring program on the
radio jet in the active galaxy M87, obtained by the KVN and VERA Array (KaVA)
at 22 GHz. This is a pilot study that preceded a larger KaVA-M87 monitoring
program, which is currently ongoing. The pilot monitoring was mostly performed
every two to three weeks from December 2013 to June 2014, at a recording rate
of 1 Gbps, obtaining the data for a total of 10 epochs. We successfully
obtained a sequence of good quality radio maps that revealed the rich structure
of this jet from <~1 mas to 20 mas, corresponding to physical scales
(projected) of ~0.1-2 pc (or ~140-2800 Schwarzschild radii). We detected
superluminal motions at these scales, together with a trend of gradual
acceleration. The first evidence for such fast motions and acceleration near
the jet base were obtained from recent VLBA studies at 43 GHz, and the fact
that very similar kinematics are seen at a different frequency and time with a
different instrument suggests these properties are fundamental characteristics
of this jet. This pilot program demonstrates that KaVA is a powerful VLBI array
for studying the detailed structural evolution of the M87 jet and also other
relativistic jets.Comment: 10 pages, 9 figures, accepted for publication in PAS
The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)
We have carried out the first very long baseline interferometry (VLBI)
imaging of 44 GHz class I methanol maser (7_{0}-6_{1}A^{+}) associated with a
millimeter core MM2 in a massive star-forming region IRAS 18151-1208 with KaVA
(KVN and VERA Array), which is a newly combined array of KVN (Korean VLBI
Network) and VERA (VLBI Exploration of Radio Astrometry). We have succeeded in
imaging compact maser features with a synthesized beam size of 2.7
milliarcseconds x 1.5 milliarcseconds (mas). These features are detected at a
limited number of baselines within the length of shorter than approximately 650
km corresponding to 100 Mlambda in the uv-coverage. The central velocity and
the velocity width of the 44 GHz methanol maser are consistent with those of
the quiescent gas rather than the outflow traced by the SiO thermal line. The
minimum component size among the maser features is ~ 5 mas x 2 mas, which
corresponds to the linear size of ~ 15 AU x 6 AU assuming a distance of 3 kpc.
The brightness temperatures of these features range from ~ 3.5 x 10^{8} to 1.0
x 10^{10} K, which are higher than estimated lower limit from a previous Very
Large Array observation with the highest spatial resolution of ~ 50 mas. The 44
GHz class I methanol maser in IRAS 18151-1208 is found to be associated with
the MM2 core, which is thought to be less evolved than another millimeter core
MM1 associated with the 6.7 GHz class II methanol maser.Comment: 19 pages, 3 figure
EAVN Astrometry toward the Extreme Outer Galaxy: Kinematic distance with the proper motion of G034.84-00.95
We aim to reveal the structure and kinematics of the Outer-Scutum-Centaurus
(OSC) arm located on the far side of the Milky Way through very long baseline
interferometry (VLBI) astrometry using KaVA, which is composed of KVN (Korean
VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We report the
proper motion of a 22 GHz HO maser source, which is associated with the
star-forming region G034.8400.95, to be (,
) = (1.610.18, 4.290.16) mas yr in
equatorial coordinates (J2000). We estimate the 2D kinematic distance to the
source to be 18.61.0 kpc, which is derived from the variance-weighted
average of kinematic distances with LSR velocity and the Galactic-longitude
component of the measured proper motion. Our result places the source in the
OSC arm and implies that G034.8400.95 is moving away from the Galactic plane
with a vertical velocity of 3816 km s. Since the H I supershell
GS033+0649 is located at a kinematic distance roughly equal to that of
G034.8400.95, it is expected that gas circulation occurs between the outer
Galactic disk around G034.8400.95 with a Galactocentric distance of
12.8 kpc and halo. We evaluate possible origins of the fast
vertical motion of G034.8400.95, which are (1) supernova explosions and (2)
cloud collisions with the Galactic disk. However, neither of the possibilities
are matched with the results of VLBI astrometry as well as spatial
distributions of H II regions and H I gas.Comment: Accepted for publication in PASJ. 14 figures; 8 table
Additional file 1: Figure S1. of The association of kidney function with repetitive breath-hold diving activities of female divers from Korea, Haenyeo
Proportion of subjects categorized by estimated glomerular filtration rate (eGFR) groups before and after propensity (PS) matching in female divers and non-divers. (TIF 864Â kb
Additional file 2: Table S1. of The association of kidney function with repetitive breath-hold diving activities of female divers from Korea, Haenyeo
Risk factors for eGFR < 45 ml/min/1.73 m2 on multivariate logistic regression analysis in the unmatched and matched cohort. (DOCX 21 kb
The Impact of Renin-Angiotensin System Blockade on Renal Outcomes and Mortality in Pre-Dialysis Patients with Advanced Chronic Kidney Disease - Fig 3
<p><b>Kaplan-Meier curves for ESRD requiring RRT (A) and composite outcome (ESRD or all-cause mortality or hospitalization for hyperkalemia) (B) in propensity score matching cohort.</b> ACEI/ARB users showed higher risk of renal mortality (A) and composite outcome (B) than non-users.</p