Maser Monitoring Organisation
A global community for maser-driven astronomy
Bio
The maser monitoring organisation is a global community of astronomers, observers and theorists collaborating to better understand the nature of astrophysical masers, their flaring behavior and their uses as tracers of astrophysical phenomena.
Introduction
Maser emission has long been used as an observational tracer of activity in astrophysical contexts, from solar system bodies, stellar births, stellar deaths and the disks of distant supermassive black holes. Their extreme brightness temperatures make them readily detectable by observational instruments, their narrow spectral line-widths make them excellent tracers of dynamical processes, additionally, knowledge of the required conditions of local densities, temperatures and radiation environments in which they arise make them effective indicators of physical conditions.
Many radio observatories conduct long-term monitoring of masers either as a main internal programme, via open-use proposals, or in the available time between PI-driven science observations, all in efforts to track flux variations. In addition to discovering periodic masers this way, monitoring programs have identified flare events where fluxes suddenly rises several orders of magnitude above their usual values, often indicating the occurrence of an energetic astrophysical event.
Maser Monitoring Organisation (M2O) was established with the goal of providing a communications platform where monitoring stations could report new flare events that could then be confirmed by other radio observatories, and followed up using interferometric imaging, very long baseline interferometry (VLBI), and flux continuum observations across the millimeter-infrared wavelength regime.
News
Credit: Charlie Willmott and Ross Burns
“Heat wave mapping” reveals a 4-arm spiral in the Keplerian accretion disk of a high-mass protostar
Six epochs of VLBI mapping conducted during the accretion burst of G358-MM1 revealed concentric rings of methanol masers which, when combined, provide a sparsely sampled view of the accretion disk kinematics. This “heat wave mapping” revealed spiral structures with morphologies suggestive of gravitational instability - one of the predicted key ingredients for episodic disk accretion.
Credit: Katharina Immer (Joint Institute for VLBI ERCI, The Netherlands)
Maser “heat-wave” in an accreting high-mass protostar
Methanol masers trace the outward propagation of thermal energy in a high-mass protostar G358-MM1, following an accretion event. Multi-epoch data were observed with the Southern Hemisphere’s Long Baseline Array.
Credit: Xi Chen (Guangzhou University, China) und Zhi-Yuan Ren (National Astronomical Observatories, Chinese Academy of Science, Beijing, China)
New maser species tracing spiral-arm accretion flows in a high-mass young stellar object
Three new molecular maser species, HDO, HNCO and 13CH3OH trace a spiral arm structure in the disk of the actively accreting high-mass protostar G358.93-0.03. Observations were conducted with the Karl G. Jansky Very Large Array (VLA; USA).
The novel merit of the M2O is its ability to identify and report new maser flare activity, enabling quick-response follow-up investigations. This is achieved by the joint efforts of individual radio telescopes which monitor the flux densities of astrophysical maser emission associated with star forming regions and evolved stars. Currently, emission in three major maser lines; the 1.6 GHz hydroxyl maser (associated with stellar envelopes), the 6.7 GHz methanol maser (associated with the disks of high-mass protostars) and the 22 GHz water maser (associated with shock regions in a variety of astrophysical contexts) of more than a thousand such sources are being frequently monitored.
Map of stations involved in the M2O
Maser emission is monitored by M2O participating radio telescopes across the globe. The majority of these stations are already already engaged in long-term maser monitoring programs of their own (blue labels), and contribute in the way of flare alerts when one of their monitored sources displays enhanced activity, while some stations shown in the map above are running observations based on dedicated proposals submitted by M2O members (green labels), and some telescopes are in the initial processes of setting up monitoring programs (grey labels). The inclusion of more telescopes enhances our ability to track more maser targets and with higher cadence, and also enables telescope gain calibration cross-checking when more than one telescope includes the same source in their monitoring source lists.
Support
The Maser Monitoring Organisation acknowledges the support of the Global Emerging Radio Astronomy Foundation (GERAF), a non-profit organisation advocating and fund-raising for radio astronomy projects around the world. Visit www.gerafoundation.com to learn more.
Additional Resources
The MaserDB is multi-purpose tool for analyzing the maser spectral data in the lines of CH3OH, H2O, OH and SiO molecules, collected from the available literature and private sources.
Visit maserdb.net to make use of this tool.
A description of the tool is given in the publication linked here.
And its use as a tool for generating scientific results is demonstrated here.
Publications
Bayandina O. S. et al., 2023, A&A, 673, A60
Nature of continuum emission in the source of the water maser super-flare G25. 65+ 1.04
McCarthy, T.P. et al., 2023, MNRAS, 552, 4728
Ammonia masers towards G 358.931-0.030
Kobak, A. et al., 2023, A&A, 671, 135
Multi-frequency VLBI observations of maser lines during the 6.7 GHz maser flare in the high-mass young stellar object G24.33+0.14
Burns, R. A. et al., 2023, Nature Astronomy, 42B
A Keplerian disk with a four-arm spiral birthing an episodically accreting high-mass protostar
Hirota, T. et al., 2022, PASJ, 74, 1234
Millimeter methanol emission in the high-mass young stellar object G24.33+0.14
Bayandina, O. S. et al., 2022, A&A, 664, 44
The evolution of the H2O maser emission in the accretion burst source G358.93−0.03
Bayandina, O. S. et al., 2022, AJ, 163, 83
A Multitransition Methanol Maser Study of the Accretion Burst Source G358.93-0.03-MM1.
McCarthy, T. P. et al., 2022, MNRAS, 509, 1681-1689
Molecular line search towards the flaring 6.7-GHz methanol masers of G 24.33+0.13 and G 359.62-0.24: rare maser transitions detected.
Volvach, A. E. et al., 2021, MNRAS, 507, L52-L56
Composite powerful short flare of water maser emission in IRAS 16293-2422.
Stecklum, B. et al., 2021, A&A, 646, A161
Infrared observations of the flaring maser source G358.93-0.03 – SOFIA confirms an accretion burst from a massive young stellar object.
Chen, X. et al., 2020, Nature Astronomy, 13 July
New maser species tracing spiral-arm accretion flows in a high-mass young stellar object
Volvach, A. E., et al., 2020, MNRAS, 496, L147–L151
Unusually powerful flare activity of the H2O maser feature near avelocity of -60 km s−1in W49N.
Volvach, A. E., et al., 2020, .MNRAS494, L59–L63
Monitoring a methanol maser flare associated with the massive star-forming region G358.93-0.03
Chen, X. et al., 2020, ApJL, 890
13CH3OH Masers Associated With a Transient Phenomenon in a High-mass Young Stellar Object.
Burns R. A. et al. 2020, Nature Astronomy, 10B
A heatwave of accretion energy traced by masers in the G358-MM1 high-mass protostar
Burns R. A. et al. 2020, MNRAS, 491, 4069B
VLBI observations of the G25.65+1.05 water maser superburst
MacLeod G. C. et al., 2019, 489, 3981
Detection of new methanol maser transitions associated with G358.93-0.03
Bayandina O. S., et al, 2019, ApJ, 884, 140B
VLA Overview of the Bursting H2O Maser Source G25.65+1.05
Volvach L. N. et al., 2019, Astronomy Reports, 63, 652V
An Unusually Powerful Water-Maser Flare in the Galactic Source W49N
Brogan C. L. et al., 2019, ApJL, 881, L39
Sub-arcsecond (Sub)millimeter Imaging of the Massive Protocluster G358.93-0.03: Discovery of 14 New Methanol Maser Lines Associated with a Hot Core
Volvach L. N. et al., 2019, A&A, 628, 89
Flaring water masers associated with W49N
Volvach L. N. et al., 2019, MNRAS, 487, L77
Unusual flare activity in the extreme-velocity -81 km s-1 water-maser feature in W49N
Breen S. L. et al., 2019, ApJL, 876, L25
Discovery of Six New Class II Methanol Maser Transitions, Including the Unambiguous Detection of Three Torsionally Excited Lines toward G 358.931-0.030
Volvach L. N. et al., 2019, MNRAS, 482, L90
Powerful bursts of water masers towards G25.65+1.05
Volvach L. N. et al., 2019 Astronomy Reports, 63, 49
A Giant Water Maser Flare in the Galactic Source IRAS 18316-0602