A5069005174- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Geophysics and Gravity Measurements
- Pulsars and Gravitational Waves Research
- Atmospheric Ozone and Climate
- Galaxies: Formation, Evolution, Phenomena
- GNSS positioning and interference
- Ionosphere and magnetosphere dynamics
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Flow Measurement and Analysis
- Silicon and Solar Cell Technologies
- Calibration and Measurement Techniques
- Restraint-Related Deaths
- Advanced Thermodynamic Systems and Engines
- Superconducting Materials and Applications
- Superconducting and THz Device Technology
- Space Science and Extraterrestrial Life
Pioneer (Japan)
2022-2024
RIKEN
2022-2024
National Astronomical Observatory of Japan
2019-2023
Korea Astronomy and Space Science Institute
2019-2023
National Institutes of Natural Sciences
2023
Ventspils University of Applied Sciences
2023
Pioneer (United States)
2023
Joint Institute for VLBI ERIC
2016-2022
Kagoshima University
2014-2019
Nicolaus Copernicus University
2019
We present the first astrometry catalog from Japanese VLBI (very long baseline interferometer) project VERA (VLBI Exploration of Radio Astrometry). have compiled all results VERA, providing accurate trigonometric annual parallax and proper motion measurements. In total, 99 maser sources are listed in catalog. Among them, 21 newly reported while rest 78 referred to previously published or those preparation for forthcoming papers. The accuracy revisited compared with other projects such as...
We report the results of VERA (VLBI Exploration Radio Astrometry) multi-epoch VLBI (very long baseline interferometry) 22 GHz water maser observations S255IR-SMA1, a massive young stellar object located in S255 star-forming region. By annual parallax source distance was measured as D|$= 1.78^{+0.12}_{-0.11}$| kpc and systemic motion (μαcos δ, μδ) = (−0.13 ± 0.20, −0.06 0.27) mas yr−1. Masers appear to trace U-shaped bow shock whose morphology proper motions are well reproduced by jet-driven...
Abstract We present (sub)millimeter imaging at 0.″5 resolution of the massive star-forming region G358.93−0.03 acquired in multiple epochs 2 and 3 months following recent flaring its 6.7 GHz CH OH maser emission. Using Submillimeter Array Atacama Large Millimeter/submillimeter Array, we have discovered 14 new Class II lines ranging frequency from 199 to 361 GHz, which originate mostly = 1 torsionally excited transitions include one transition. The latter detection provides first...
Abstract We report the first detection of isotopic methanol ( 13 CH 3 OH) maser emission in interstellar space. The was detected toward high-mass young stellar object G358.93-0.03 during monitoring a flare 6.7 GHz (CH this source. find that spectral and spatial distribution OH masers differs from imaged at same epoch, contrary to expectations similarity their pumping. This conclusively demonstrates are bright under different physical conditions suggests they can provide additional,...
We report the detection of new 12.178, 12.229, 20.347, and 23.121 GHz methanol masers in massive star-forming region G358.93-0.03, which are flaring on similarly short timescales (days) as 6.668 also associated with this source. The brightest 12.178 channel increased by a factor over 700 just 50 d. found 12.229 20.347 transitions first ever reported is only fourth object to exhibit masers. maser emission appears have higher flux density than that emission, unusual. No near-infrared flare...
Context. Recent studies have shown that 6.7 GHz methanol maser flares can be a powerful tool for verifying the mechanisms of production and even specific signatures accretion rate changes in early stages high-mass star formation. Aims. We characterize spatial structure evolution water masers during flare emission at young stellar object (HMYSO) G24.33+0.14. Methods. Very Long Baseline Array (VLBA) was used to image 12.2 22.2 vapor three epochs guided by monitoring line with Torun 32m...
We report on annual parallax and proper motion observations of H2O masers in S235AB-MIR, which is a massive young stellar object the Perseus Arm. Using multi-epoch VLBI (very long baseline interferometry) astrometry we measured π = 0.63 ± 0.03 mas, corresponding to trigonometric distance |$D= 1.56^{+0.09}_{-0.08}$| kpc, source (μαcos δ, μδ) (0.79 0.12, −2.41 0.14) mas yr−1. Water trace jet diameter 15 au exhibits definite radial velocity gradient perpendicular its axis. 3D maser kinematics...
We present the most complete to date interferometric study of centimeter wavelength methanol masers detected in G358.93-0.03 at burst and post-burst epochs. A unique, NIR/(sub)mm-dark FIR-loud MYSO accretion was recently discovered G358.93-0.03. The event accompanied by flares an unprecedented number rare maser transitions. first images three newly-discovered 6.18, 12.23, 20.97 GHz are presented this work. spatial structure evolution 6.67, 12.18, 23.12 is studied two emission all transitions...
We carried out observations of the 22 GHz H2O masers in a high-mass protostar S255 NIRS 3 by using VERA. measured proper motions associated with bipolar outflow. The expansion velocity blueshifted bow shock traced was 28 km s-1 corresponding to dynamical timescale 60 years. direction maser outflow is slightly tilted compared radio jet, which could suggest more recent ejection episode during accretion burst event. total flux density has gradually increased from early 2017 and become almost...
Abstract In 2019 September, a sudden flare of the 6.7 GHz methanol maser was observed toward high-mass young stellar object (HMYSO) G24.33+0.14. This may represent fourth detection transient mass accretion event in an HMYSO after S255IR NIRS3, NGC 6334I-MM1, and G358.93−0.03-MM1. G24.33+0.14 is unique among these sources as it clearly shows repeating with 8 yr interval. Using Atacama Large Millimeter/submillimeter Array (ALMA), we millimeter continuum molecular lines pre-flare phase 2016...
We present the results of multi-epoch VLBI observations water masers in AGFL 5142 massive star forming region. measure an annual parallax $\pi=0.467 \pm 0.010$ mas, corresponding to a source distance $D=2.14^{+0.051}_{-0.049}$ kpc. Proper motion and line sight velocities reveal 3D kinematics this region, most which associate with millimeter sources from literature. In particular we find remarkable bipolar bowshocks expanding member, AFGL MM1, are used investigate physical properties its...
We measured the trigonometric parallax of H2O maser source in M17 cluster-forming region to be 0.491 ± 0.041 mas, corresponding a distance 2.04|$^{+0.16}_{-0.17}$| kpc with 8 per cent accuracy. This result is consistent Very Long Baseline Array (VLBA) previous measurement 12.2 GHz CH3OH masers M17–UC1. performed first relative proper motions feature 2, and its morphology traces an expanding arcuate shell mean motion ∼ 19.4 km s−1. The redshifted component also shows motion. Fitting uniformly...
ABSTRACT The Search for Extra-Terrestrial Intelligence (SETI) has been conducted over 60 yr, yet no technosignatures have identified. Previous studies focused on stars in our Galaxy, with few searches the extragalactic Universe despite a larger volume being available. Civilizations capable of harvesting energy from star or galaxy are classified as KII KIII Kardashev scale, respectively. Technosignatures such advanced civilizations would be extremely luminous and detectable by current radio...
ABSTRACT We report the detection of ammonia masers in non-metastable (6, 3), (7, 5), and 5) transitions; latter being first unambiguous maser that transition ever made. Our observations include very long baseline interferometry emission, which allowed effective constraining brightness temperature. The were detected towards G 358.931−0.030, a site 6.7-GHz class II methanol emission was recently reported to be undergoing period flaring activity. These appear contemporaneously with during...
We performed NH$_3\ (J,K)=(1,1),(2,2),$ and $(3,3)$ mapping observations toward the Galactic massive star-forming region Sh 2-255 2-257 using Nobeyama 45-m telescope as a part of KAGONMA (KAgoshima Object survey with 45-metre by Mapping in Ammonia lines) project. NH$_3$ (1,1) has an intensity peak at cluster S255 N, is distributed over 3 pc $\times$ 2 located between two HII regions. The kinetic temperature derived from NH$_3 (2,2)/(1,1)$ ratio was $\sim 35$ K near IR. These clusters also...
We investigated the star formation activities in AFGL333 region, which is vicinity of W4 expanding bubble, by conducting NH3 (1,1), (2,2), and (3,3) mapping observations with 45 m Nobeyama Radio Telescope at an angular resolution 75". The morphology (1,1) map shows a bow-shape structure size 2.0 x 0.6 pc as seen dust continuum. At interface between bubble dense cloud, compact HII region G134.2+0.8, associated IRAS02245+6115, located. Interestingly, just north south G134.2+0.8 we found...
This paper reports observations of a 22 GHz water maser `superburst' in the G25.65+1.05 massive star forming region, conducted response to an alert from Maser Monitoring Organisation (M2O). Very long baseline interferometry (VLBI) using European VLBI Network (EVN) recorded flux density $1.2 \times 10^{4}$ Jy. The superburst was investigated spectral, structural and temporal domains its cause determined be increase path length generated by superposition multiple emitting regions aligning line...
Abstract Long-period Mira variable stars are considered to have relatively high initial masses and may be potentially useful as tracers of spiral arm structure the Milky Way. From 2004 2017, we monitored long-period candidates selected from IRAS color–color diagram in near-infrared K ′ band. As an result this study, found 108 variables determined their periods, mean magnitudes, amplitudes. Most them located between 0° 90° Galactic longitude. The peak period distribution is at around 500...
We report our measurement of the trigonometric distance and proper motion IRAS 20056+3350, obtained from annual parallax H2O masers. Our D = 4.69 +0.65-0.51 kpc, which is more than two times larger near kinematic adopted in literature, places 20056+3350 at leading tip Local arm, proximal to Solar circle. Using we re-evaluate past observations reveal as a site massive star formation young stage evolution. This result consistent with spectral energy distribution source evaluated published...
Abstract In this paper, we report new detections of SiO v = 1 and 2 J → 0 masers in the “water fountain” source IRAS 16552−3050, which was observed with Nobeyama 45 m telescope during 2021 March–April. Water fountains are evolved stars whose H O maser spectra trace high-velocity outflows >100 km s −1 . This is second known case a water fountain, after their prototypical source, W 43A. These should shed light on evolutionary status category stars, likely to be at end asymptotic giant...
Water fountains are evolved stars showing early stages of collimated mass loss during transition from the asymptotic giant branch, providing valuable insight into formation asymmetric planetary nebulae. We report results multi-epoch VLBI observations, which determine spatial and three-dimensional kinematic structure H2O masers associated with water fountain IRAS 18113-2503. The trace three pairs high-velocity (~150-300 km/s) bipolar bow shocks on a scale 0.18'' (~2000 au). expansion...
We conducted astrometric VLBI observations of water-vapor maser emission in the massive star forming region IRAS 21379+5106 to measure annual parallax and proper motion, using VERA. The was measured be $0.262 \pm 0.031$ mas corresponding a trigonometric distance $3.82^{+0.51}_{-0.41}$ kpc. motion $(\mu_\alpha\cos{\delta}, \mu_\delta)=(-2.74 0.08, -2.87 0.18)$ yr$^{-1}$. Using this result, Galactic rotational velocity estimated $V_\theta=218\pm 19$ km s$^{-1}$ at Galactocentric...