scholarly journals Rotational parallaxes of nearby galaxies

2012 ◽  
Vol 8 (S289) ◽  
pp. 226-226
Author(s):  
Andreas Brunthaler
Keyword(s):  
High Mass ◽  
Mass Star ◽  
Proper Motions ◽  
Star Forming ◽  
Star Forming Regions ◽  
Long Baseline ◽  
First Results ◽  
Systematic Effects ◽  
Nearby Galaxies ◽  
Water Masers

AbstractAccurate geometric distances, which are inherently free of systematic effects are of very great importance for an independent recalibration of extragalactic distance estimators. Local Group galaxies are close enough for both primary and secondary distance indicators to be readily isolated in ground- and space-based observations. Astrometric accuracies of a few micro-arcseconds based on Very Long Baseline Interferometry (VLBI) observations of water masers in high-mass star-forming regions in nearby galaxies allow a measurement of the proper motions of these masers. Since these high-mass star-forming regions rotate with the galaxies, one can deduce a rotational parallax by comparing the known rotation curve with the proper motions of the masers. I provide an update of our previous rotation parallax of M33 and show first results of observations of the recently discovered water masers in the Andromeda galaxy (M31).

scholarly journals 22 GHz Water Maser Survey of the Xinjiang Astronomical Observatory

2012 ◽  
Vol 8 (S287) ◽  
pp. 296-297
Author(s):  
Jian-jun Zhou ◽  
Jarken Esimbek ◽  
Gang Wu
Keyword(s):  
Galactic Plane ◽  
Astronomical Observatory ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Gas Kinematics ◽  
Star Forming Regions ◽  
Water Masers ◽  
Maser Sources ◽  
Water Maser

AbstractWater masers are good tracers of high-mass star-forming regions. Water maser VLBI observations provide a good probe for studying high-mass star formation and galactic structure. We plan to make a blind survey toward the northern Galactic plane in future years using the 25 m radio telescope of the Xinjiang Astronomical Observatory. We will select some water maser sources discovered in the survey and perform high resolution observations to study the gas kinematics close to high-mass protostars.

scholarly journals Water Masers Toward Star-Forming Regions in the Bolocam Galactic Plane Survey

2012 ◽  
Vol 8 (S287) ◽  
pp. 286-287 ◽  
Author(s):  
Miranda K. Dunham ◽  
Keyword(s):  
Physical Properties ◽  
Galactic Plane ◽  
Dust Emission ◽  
High Mass ◽  
Evolutionary Stage ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Water Masers ◽  
Green Bank Telescope

AbstractWe present preliminary results of a search for 22 GHz water masers toward 1400 star-forming regions seen in the Bolocam Galactic Plane Survey (BGPS) using the Green Bank Telescope (GBT). The BGPS is a blind survey of the Northern Galactic plane in 1.1 mm thermal dust emission that has cataloged star-forming regions at all evolutionary stages. Further information is required to determine the stage of each BGPS source. Since water masers are produced by outflows from low and high-mass star forming regions, their presence is a key component of determining whether the BGPS sources are forming stars and which evolutionary stage they are in. We present preliminary detection statistics, basic properties of the water masers, and correlations with physical properties determined from the 1.1 mm emission and ammonia observations obtained concurrently with the water masers on the GBT.

scholarly journals 325 GHz Water Masers in Orion Source I

2012 ◽  
Vol 8 (S287) ◽  
pp. 184-185
Author(s):  
Florian Niederhofer ◽  
Elizabeth Humphreys ◽  
Ciriaco Goddi ◽  
Lincoln J. Greenhill
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
High Mass ◽  
Mass Star ◽  
Compact Disk ◽  
Volume Source ◽  
Star Forming ◽  
Star Forming Regions ◽  
Water Masers ◽  
Excitation Conditions

AbstractRadio Source I in the Orion BN/KL region provides the closest example of high mass star formation. It powers a rich ensemble of SiO and H2O masers, and is one of only three star-forming regions known to display SiO maser emission. Previous monitoring of different SiO masers with the VLBA and VLA has enabled the resolution of a compact disk and a protostellar wind at radii <100 AU from Source I, which collimates into a bipolar outflow at radii of 100-1000 AU (see contribution by Greenhill et al., this volume). Source I may provide the best case of disk-mediated accretion and outflow recollimation in massive star formation. Here, we report preliminary results of sub-arcsecond resolution 325 GHz H2O maser observations made with the SMA. We find that 325 GHz H2O masers trace a more collimated portion of the Source I outflow than masers at 22 GHz, but occur at similar radii suggesting similar excitation conditions. A velocity gradient perpendicular to the outflow axis, indicating rotation, supports magneto-centrifugal driving of the flow.

scholarly journals The distance to G59.7+0.1 and W3OH

2007 ◽  
Vol 3 (S248) ◽  
pp. 214-216
Author(s):  
Y. Xu ◽  
M. J. Reid ◽  
K. M. Menten ◽  
X. W. Zheng ◽  
A. Brunthaler ◽  
...  
Keyword(s):  
High Mass ◽  
Radio Sources ◽  
Mass Star ◽  
Proper Motions ◽  
Extragalactic Radio Sources ◽  
Star Forming ◽  
Long Baseline ◽  
Methanol Masers ◽  
Very Long Baseline Array

AbstractWe have measured the distance to the high-mass star-forming region G59.7+0.1 (IRAS 19410+2336) and W3OH. Their distances, 2.20 ± 0.11 kpc and 1.95 ± 0.04 kpc, respectively, were determined by triangulation using Very Long Baseline Array (VLBA) observations of 12.2 GHz methanol masers phase-referenced to compact extragalactic radio sources. In addition to the distances, we have also obtained their proper motions.

scholarly journals Where methanol masers spring

2007 ◽  
Vol 3 (S242) ◽  
pp. 178-179
Author(s):  
Karl J. E. Torstensson ◽  
Huib Jan van Langevelde ◽  
Stephen Bourke
Keyword(s):  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Methanol Maser ◽  
Star Forming Regions ◽  
Surrounding Environment ◽  
First Results ◽  
Vlbi Data ◽  
Methanol Masers ◽  
Cepheus A

AbstractWe are carrying out a program to observe the 6.7 GHz methanol maser emission in high-mass star-forming regions using large FOV (~2'), astrometric, VLBI data. Here we report on the first results of the inner few arc seconds in Cepheus A East. We find a maser filament extending over ~1.7” (1200 AU), straddling the waist of Cep A HW2. The region in which the CH3OH masers are found contains several YSO's and it is not clear whether the CH3OH masers are associated with several different objects or rather the larger scale surrounding environment.

scholarly journals Newly detected H2O Masers in Seyfert and Starburst Galaxies

2005 ◽  
Vol 13 ◽  
pp. 851-853 ◽  
Author(s):  
A. B. Peck ◽  
A. Tarchi ◽  
C. Henkel ◽  
N. M. Nagar ◽  
J. Braatz ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Massive Star ◽  
Chemical Properties ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Nearby Galaxies ◽  
Maser Sources

AbstractWe report new detections of three H2O megamasers and one kilomaser using the Effelsberg 100-m telescope. Isotropic luminosities are ~50, 300, 1, and 230 L⊙ for Mrk 1066, Mrk 34, NGC 3556, and Arp 299, respectively. Mrk 34 contains the most distant H2O megamaser ever detected in a Seyfert. Our targets in this survey were chosen to fit one of the following criteria: 1) to have a high probability of interaction between the radio jet and the ISM within the central few parsecs of the radio galaxy, yielding masers which arise in local molecular clouds; or 2) to have very bright IRAS sources in which massive star forming regions might yield powerful masers. The ‘jet maser’ sources can provide detailed information about the conditions in the ISM in the central 1-10 pc of AGN. The extra-galactic ‘star formation masers’ can be used to pinpoint and characterize locations of high mass star formation in nearby galaxies. In addition, these sources will help to provide a better understanding of the chemical properties of molecular clouds in extra-galactic systems.

scholarly journals Herschel-HIFI observations of H2O in high-mass star-forming regions: first results

2011 ◽  
Vol 52 ◽  
pp. 201-204
Author(s):  
F. van der Tak ◽  
F. Herpin ◽  
F. Wyrowski ◽  
Keyword(s):  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
First Results

scholarly journals Parallax of Star-forming Region G027.22+0.14

2022 ◽  
Vol 163 (2) ◽  
pp. 54
Author(s):  
S. B. Bian ◽  
Y. Xu ◽  
J. J. Li ◽  
Y. W. Wu ◽  
B. Zhang ◽  
...  
Keyword(s):  
Proper Motion ◽  
High Mass ◽  
Mass Star ◽  
Proper Motions ◽  
Star Forming ◽  
Long Baseline ◽  
Trigonometric Parallax ◽  
Peculiar Motion ◽  
Very Long Baseline Array ◽  
Lower Luminosity

Abstract Using the Very Long Baseline Array, we measured the trigonometric parallax and proper motions toward a 6.7 GHz methanol maser in the distant high-mass star-forming region G027.22+0.14. The distance of this source is determined to be 6.3 − 0.5 + 0.6 kpc. Combining its Galactic coordinates, radial velocity, and proper motion, we assign G027.22+0.14 to the far portion of the Norma arm. The low peculiar motion and lower luminosity of G027.22+0.14 support the conjecture by Immer et al. that low-luminosity sources tend to have low peculiar motions.

scholarly journals VLBI observations of H2O and CH3OH masers in two high-mass YSOs

2007 ◽  
Vol 3 (S242) ◽  
pp. 152-153
Author(s):  
C. Goddi ◽  
L. Moscadelli ◽  
A. Sanna ◽  
R. Cesaroni ◽  
V. Minier
Keyword(s):  
Large Scale ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Disk Wind ◽  
Star Forming Regions ◽  
Vlbi Observations ◽  
Circumstellar Gas ◽  
Methanol Masers ◽  
Water Masers

AbstractWe have conducted phase-reference VLBI observations of H2O and CH3OH masers toward two high-mass star forming regions, Sh 2-255 IR and AFGL 5142. In Sh 2-255 infrared water masers are aligned along a direction close to the orientation of a large scale H2 jet, tracing possibly shocked material in a precessing jet, or, alternatively, the disk-wind emerging from the disk atmosphere. In AFGL 5142 water masers trace expansion at the base of a protostellar jet, whilst methanol masers are more probably tracing infalling than outflowing gas. Our results suggest that water and methanol masers trace different kinematic structures in the circumstellar gas.

Maser Emission in G 339.884−1.259

2017 ◽  
Vol 13 (S336) ◽  
pp. 334-335
Author(s):  
V. Krishnan ◽  
L. Moscadelli ◽  
S. P. Ellingsen ◽  
H. E. Bignall ◽  
S. L. Breen ◽  
...  
Keyword(s):  
Star Formation ◽  
High Mass ◽  
Mass Star ◽  
Proper Motions ◽  
Star Formation Region ◽  
Formation Region ◽  
Gas Kinematics ◽  
Long Baseline ◽  
Vlbi Observations ◽  
Water Masers

AbstractWe present multi–epoch VLBI observations of the methanol and water masers in the high–mass star formation region G 339.884−1.259, made using the Australian Long Baseline Array (LBA). Our sub–milliarcsecond precision measurements trace the proper motions of individual maser features in the plane of the sky. When combined with the direct line–of–sight radial velocity (vlsr), these measure the 3 D gas kinematics of the associated high–mass star formation region, allowing us to probe the dynamical processes to within 1000 AU of the core.

Sign in / Sign up

Export Citation Format

Share Document