Results 1 to 10 of about 1,279 (175)
Pumping the interstellar methanol masers [PDF]
Monthly Notices of the Royal Astronomical Society, 1992 The pumping of interstellar methanol masers is studied, covering a range of excitation conditions. The Class I (Class A) masers result from collisional excitation followed by spontaneous radiative decay. Masers appear in low-frequency transitions where the upper state is strongly favoured by large Einstein A coefficients, associated with high-frequency
D M Cragg, P D Godfrey, Ronald D Brown
exaly +3 more sources
VLBI observations of interstellar ammonia masers
Astrophysical Journal, 1991 The first VLBI measurement of interstellar ammonia masers is reported. The positions, as well as size and brightness temperature limits, for the masers in the NH 3 (9, 6) inversion transition that are associated with the ultracompact H II regions W51 e1 and e2 are obtained. The masers arise from two positions, each of which is located close to but not
K M Menten, M J Reid, C M Walmsley
exaly +3 more sources
Broadband VLA Spectral-line Survey of a Sample of Ionized Jet Candidates
The Astrophysical Journal Supplement Series, 2023 The study of the interaction between ionized jets, molecular outflows, and their environments is critical to understanding high-mass star formation, especially because jets and outflows are thought to be key in the transfer of angular momentum outward ...
E. Sanchez-Tovar +4 more
doaj +1 more source
Proper Motions of Water Masers in W49 N Measured by KaVA
The Astrophysical Journal, 2023 We report the proper motions of 22 GHz water masers toward W49 N that were observed by the KVN and VERA Array (KaVA) during 2017 February–May. We found 263, 268, and 310 features in three successive epochs; they were distributed in a region of size 4 × 4
Kitiyanee Asanok +8 more
doaj +1 more source
NAVIGATION, Volume 68, Issue 4, Page 687-708, Winter 2021., 2021 Abstract A server satellite that is parked in a stable distant retrograde orbit (DRO) in the vicinity of the Moon can provide navigation service for satellites in the Earth–Moon system. In this study, X‐ray pulsar navigation (XPNAV) is investigated to determine the server's orbital position and velocity, and maintain its onboard timing autonomously to ...
Jiangkai Liu +4 more
wiley +1 more source
FIRST INTERSTELLAR HCO + MASER [PDF]
The Astrophysical Journal, 2012 4 pages, 3 figures, accepted by ApJL on September 10 ...
Hakobian, Nicholas S. +1 more
openaire +2 more sources
Simultaneous Time-monitoring Observations of H2O and SiO Masers toward the Supergiant VX Sagittarii
The Astrophysical Journal Supplement Series, 2023 We performed simultaneous monitoring observations of the 22.2 GHz H _2 O and 43.1/42.8/86.2/129.3 GHz SiO masers toward the red supergiant VX Sagittarii using the Korean VLBI Network single-dish telescopes.
Dong-Hwan Yoon +4 more
doaj +1 more source
Luminosity Outburst of a High-mass Young Stellar Object Triggered by the Surrounding Radiation Field
The Astrophysical Journal Letters, 2023 We present observations of the 6.7 GHz methanol and 4.8 GHz formaldehyde masers toward the high-mass young stellar object G24.33+0.14 (hereafter G24). Our observations were conducted from 2019 to 2021 using the Shanghai Tianma 65 m Radio Telescope and ...
Jun-Ting Liu +10 more
doaj +1 more source
Luminosity Outburst Energized by the Collision between the Infalling Streamer and Disk in W51 North
The Astronomical Journal, 2023 We report the detection of the disk/torus, outflow, and inflow structures traced by H _2 O masers toward a high-mass young stellar object W51 North during its H _2 O maser outburst stage using the Karl G. Jansky Very Large Array (VLA).
Yan-Kun Zhang +3 more
doaj +1 more source
The Parallax and 3D Kinematics of Water Masers in the Massive Star-forming Region G034.43+0.24
The Astrophysical Journal, 2023 We report a measurement of the trigonometric parallax of 22 GHz water masers in the massive star-forming region G034.43+0.24 as part of the Bar and Spiral Structure Legacy Survey using the Very Long Baseline Array.
Xiaofeng Mai +14 more
doaj +1 more source