The Maser Monitoring Organisation (M2O) is a research community of telescope operators, astronomy researchers and maser theoreticians pursuing a joint goal of reaching a deeper understanding of maser emission and exploring its variety of uses as tracers of astrophysical events. These proceedings detail the origin, motivations and current status of the M2O, as was introduced at the 2021 EVN symposium

Aberfelds, Artis

Abraham, Zulema

Alakoz, Alexei

Baan, Willem

Bartkiewicz, Anna

BAYANDINA, Olga

Bisyarina, Anastasia

BRAND, JAN

Breen, Shari

Brogan, Crystal

Burns, Ross A.

CARATTI O GARATTI, ALESSIO

CASU, Silvia

Chen, Xi

Chibueze, James O.

Colomer, Fransisco

Cyganowski, Claudia

Durjasz, Michał

Dzodzomenyo, Andrews

Eislöffel, Jochen

Ellingsen, Simon

Engels, Dieter

Goedhart, Sharmila

Gong, Yan

Gray, Malcolm

Green, Jimi

Gulyaev, Sergei

Hirota, Tomoya

Hoare, Melvin

Hunter, Todd

Imai, Hiroshi

Immer, Katharina

Johnstone, Doug

Jordan, Lucas

Khaibrakhmanov, Sergey

Kim, Jungha

Kim, Kee Tae

Kobak, Agnieszka

Kramer, Busaba

Kumar, Jayender

Kurtz, Stan

Ladeyschikov, Dmitry

Li, Dalei

Linz, Hendrik

Macdonald, Callum

MacLeod, Gordon

Menten, Karl

Miro, Cristina Garcia

MOSCADELLI, Luca

Natusch, Tim

Olech, Mateusz

Orosz, Gabor

Popova, Elena

Proven-Adzri, Emmanuel

Shakhvorostova, Nadya

Shmeld, Ivar

Smits, Derck

Sobolev, Andrey

Stecklum, Bringfried

Sugiyama, Koichiro

Sunada, Kazuyoshi

Surcis, Gabriele

Szabó, Zsófia Marianna

Szymczak, Marian

Tolmachev, Alexander

Uchiyama, Mizuho

Uscanga, Lucero

Valtts, Irina

van den Heever, Fanie

van Langevelde, Huib

Vlemmings, Wouter

Volvach, Alexandr

Volvach, Larisa

Vorster, Job

Weston, Stuart

Wolak, Pawel

Wootten, Alwyn

Wu, Gang

Yonekura, Yoshinori

Yoshihiro, Tanabe

OA@INAF - Istituto Nazionale di Astrofisica

2022Publication Year2022-07-20T10:51:01ZAcceptance in OA@INAFRecent updates on the Maser Monitoring OrganisationTitleBurns, Ross A.; Kobak, Agnieszka; CARATTI O GARATTI, ALESSIO; Tolmachev, Alexander; Volvach, Alexandr; et al.Authors10.22323/1.399.0019DOIhttp://hdl.handle.net/20.500.12386/32528HandlePOS PROCEEDINGS OF SCIENCEJournal399NumberPoS(EVN2021)019Recent updates on the Maser Monitoring OrganisationRoss A. Burns,∗ Agnieszka Kobak, Alessio Caratti o Garatti, AlexanderTolmachev, Alexandr Volvach, Alexei Alakoz, Alwyn Wootten, AnastasiaBisyarina, Andrews Dzodzomenyo, Andrey Sobolev, Anna Bartkiewicz, ArtisAberfelds, Bringfried Stecklum, Busaba Kramer, Callum Macdonald, ClaudiaCyganowski, Fransisco Colomer, Cristina Garcia Miro, Crystal Brogan, Dalei Li,Derck Smits, Dieter Engels, Dmitry Ladeyschikov, Doug Johnstone, ElenaPopova, Emmanuel Proven-Adzri, Fanie van den Heever, Gabor Orosz, GabrieleSurcis, Gang Wu, Gordon MacLeod, Hendrik Linz, Hiroshi Imai, Huib vanLangevelde, Irina Valtts, Ivar Shmeld, James O. Chibueze, Jan Brand, JayenderKumar, Jimi Green, Job Vorster, Jochen Eislöffel, Jungha Kim, KoichiroSugiyama, Karl Menten, Katharina Immer, Kazuyoshi Sunada, Kee-Tae Kim,Larisa Volvach, Luca Moscadelli, Lucas Jordan, Lucero Uscanga, Malcolm Gray,Marian Szymczak, Mateusz Olech, Melvin Hoare, Michał Durjasz, MizuhoUchiyama, Nadya Shakhvorostova, Olga Bayandina, Pawel Wolak, SergeiGulyaev, Sergey Khaibrakhmanov, Shari Breen, Sharmila Goedhart, Silvia Casu,Simon Ellingsen, Stan Kurtz, Stuart Weston, Tanabe Yoshihiro, Tim Natusch,Todd Hunter, Tomoya Hirota, Willem BAAN, Wouter Vlemmings, Xi Chen, YanGong, Yoshinori Yonekura, Zsófia Marianna Szabó and Zulema AbrahamThe Maser Monitoring OrganisationE-mail: ross.burns@nao.ac.jpThe Maser Monitoring Organisation (M2O) is a research community of telescope operators,astronomy researchers and maser theoreticians pursuing a joint goal of reaching a deeper under-standing of maser emission and exploring its variety of uses as tracers of astrophysical events.These proceedings detail the origin, motivations and current status of the M2O, as was introducedat the 2021 EVN symposium.*** European VLBI Network Mini-Symposium and Users’ Meeting (EVN2021) ****** 12-14 July, 2021 ****** Online ***∗Speaker© Copyright owned by the author(s) under the terms of the Creative CommonsAttribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). https://pos.sissa.it/PoS(EVN2021)019Recent updates on the Maser Monitoring Organisation Ross A. Burns1. The Maser Monitoring OrganisationMaser emission has long been used as an observational tracer of activity in astrophysicalcontexts, from solar system bodies, stellar births, stellar deaths and the disks of distant supermassiveblack holes. Their extreme brightness temperatures make them readily detectable by observationalinstruments, their narrow spectral line-widths make them excellent tracers of dynamical processes,additionally, knowledge of the required conditions of local densities, temperatures and radiationenvironments in which they arise make them effective indicators of physical conditions.Maser emission is very sensitive to its environment; a change in physical conditions and thepresence/lack of shocks can selectively favor or unfavor the pumping/sink mechanism of differentmaser transitions, effectively switching them on or off, or causing temporal variations as thelocal environment approaches or deviates from what is required to produce maser activity. Thisselectivity of masers results in specific transitions often found to associate with, and thus trace,specific astrophysical environments and structures; the 6.7 GHz methanol maser typically associateswith high-mass protostellar disks, and the 22 GHz water maser typically associates with shocks inproto-/stellar jets. Multi-epoch radio observations of multiple maser species and transitions can thuslocate disks, shocks, outflows and other structures in deeply embedded systems that are otherwiseinaccessible to observation, in addition to tracing their evolution.Many radio observatories conduct long-term monitoring of masers either as a main internalprogramme, 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, monitoringprograms have identified flare events where fluxes suddenly rises several orders of magnitude abovetheir usual values, often indicating the occurrence of an energetic astrophysical event. In a case ofextremely fortunate timing, during the IAUS 336 symposium on astrophysical masers in September2017 word surfaced of two large maser flares in high-mass star forming regions G25.65+1.05 andW49N. News of these events quickly became popular focal points at coffee breaks and ultimately thetimely gathering of maser experts and observers facilitated the organisation of immediate requestsof directors’ discretionary time for follow-up maser imaging observations with several VLBI arrays.Presenters at the symposium had also reported several past maser flares witnessed in their monitoringcampaigns, but had not been followed up at the time - an opportunity thereby missed since suchflares proved to be short-lived. In light of the need for prompt and organised follow-up responsesto maser flares, and in the excitement of the G25.65+1.05 and W49N events, the Maser MonitoringOrganisation (M2O) was established during an interlude between talks. Its initial goal was ofproviding a communications platform where monitoring stations could report new flare events thatcould then be confirmed by other radio observatories, and followed up using VLBI observations.2. M2O: General operationAt its core, the M2O is a communications platform which connects radio observatories witheach other, with follow-up facility users, with maser theorists who contribute knowledge of maserproduction and behaviour, and with experts of various astrophysical systems, such as regions of starformation, who consider the available information in the context of its environment. Observationalresources acquired for use in quick-response follow-ups are available and their use determined2PoS(EVN2021)019Recent updates on the Maser Monitoring Organisation Ross A. BurnsFigure 1: General flow of an M2O response to a new maser flare, coloured arrows match coloured textcollectively by the community, in that if a maser flare event appears to be interesting then aproportional investment of resources is undertaken. This can range from zero to up to around100 hours across many facilities as was the case for G358.93-0.03 (see below). Furthermore,key members representing a monitoring station that reports a maser flare event to the M2O aresubsequently included as co-authors in all subsequent publications following up the flare eventas appreciation for the flare alert itself and to incentivise continued reporting. Open sharing ofinformation and observing resources seem to have been key to the recent success of the M2O.3. The G358.93-0.03 maser flareThe G358.93-0.03 maser flare event and follow-up campaign became the first large-scale andfocused flare pursuit of the M2O into which more than 20 follow-up observing requests wereinvested. G358.93-0.03 is a high-mass star forming region in the Galactic centre direction, whichwas first identified by its 6.7 GHz methanol maser emission [1]. This maser had been monitoredby the Hitachi 32-m radio telescope team operated by Ibaraki University, who reported maser flareactivity to the M2O on the 18th of Jan 2019. Tracking the evolution of the 6.7 GHz methanolmaser transition showed that the burst reached peak brightness some 70 days later [2] followed by abrightness reduction over ∼ 4 months, at which time the main flare phase appeared to have subsided.Follow-up ALMA observations revealed a cluster of 7 millimeter cores, of which G358-MM1 was identified as the progenitor of the maser flare. It exhibited hot core chemistry andspatio-kinematics indicative of rotation [3] and spiral-like substructures [4]. During the flarestate, high-resolution imaging of the 6.7 GHz methanol maser revealed a ’heat-wave’ of accretionenergy propagating outward from G358-MM1 at subluminal speeds [5]. Measurements of the pre-,mid- and post-burst phase infrared spectral energy distribution enabled by SOFIA observationsconcluded that G358-MM1 gained 𝑀𝑎𝑐𝑐 = 5.3+11.1−4.4 × 10−4𝑀⊙ of mass during the accretion burst[6], and independent agreement was obtained for estimates of the stellar mass (∼ 9𝑀⊙) and systeminclination (22 degrees from face-on) in analyses of dynamics traced by spectral line data with theVLA [4] and ALMA [3], and in infrared radiative transfer modelling analyses [6]. At the time3PoS(EVN2021)019Recent updates on the Maser Monitoring Organisation Ross A. Burnsof writing 27 new maser transitions have been discovered in association with the accretion burstwhose utility as possible new astrophysical tracers is now being explored [2–4, 7, 8] The M2O-ledinvestigations into G358-MM1 produced to what is at present the most recently identified, andperhaps the most intensely studied accretion burst event of a high-mass protostar.4. Current Status of the M2O: Membership, Flares, Publications, ResourcesThe M2O currently has 80 members, spanning Europe, Asia, the Americas and Australasia,and includes individuals at all levels of academic progression from students, through postdocsand professors, to directors of research institutes. To date, 15 flares have been reported to theM2O, comprising events identified by seven flares of 6.7 GHz methanol masers and eight 22GHz water masers. Follow-up campaigns were initiated for 12 of these flares, of which 6 targetshave generated publications: W49N, G25.65+1.05, G358.93-0.03, G24.33+0.14, G359.617-0.251,IRAS16293-2422, with more on the way (see the website1 for an up-to-date list of publications).150° 120° 90° 60° 30° 0° 330° 300° 270° 240° 210°-75°-60°-45°-30°-15°0°15°30°45°60°75°M2O source sky coverage22 GHz water6.7 GHz methanol1.6 GHz hydroxylFigure 2: Left: Global distribution maser monitoring observatories with internal programmes (blue icons),those used as open-use (green icons), and those indicating interest in contributing in the future (grey icons).Right: Distribution of maser targets monitored by the cumulative of M2O participating stations. Regularlyupdated, high quality versions of these maps can be accessed at the M2O website.The most vital resource of the M2O is the maser monitoring stations which search, identify andreport new maser flare events by monitoring large numbers of maser targets at observing cadencestypically between days and weeks. Most of the observatories’ monitoring programs predate theM2O by years or even decades, as indeed the M2O is merely the collaboration of efforts amongstobservatories and other maser enthusiasts. At present 9 observatories monitor as part of theirinternal programmes, 3 observatories are used for monitoring as part of open-use proposals, 3 morestations have shown interest in joining (Figure 2, left). At present around 1000 maser targets arebeing monitored by the cumulative efforts of M2O monitoring stations. Uniquenesses in hardware,latitudes and time available gives rise to an arbitrary sky coverage of targets where biases towardthe Galactic plane and northern hemispheres can be seen in the 1.6 GHz hydroxyl and 6.7 GHzmethanol, and the 22 GHz water masers, respectively (Figure 2, right).1https://www.masermonitoring.org4PoS(EVN2021)019Recent updates on the Maser Monitoring Organisation Ross A. BurnsAnother important resource is access to follow-up facilities, especially those providing imaging.To facilitate rapid responses to new maser flare alerts the M2O maintains access to this resourcethrough triggerable Target of Opportunity proposals on the VLA, SMA, ATCA, ALMA, EVN, LBA,VLBA, KaVA, EAVN, Subaru, SOFIA and the JWST. Additionally the M2O also collaborates withother large programs by sharing flare information, expertise (another key resource) and in certainconditions observational resources - with teams such as the JCMT Transients Program2 and theKaVA Star Formation Large Program3, driven by a shared goal of broadening the wavelengthcoverage of follow-up investigations into time-variable astrophysical phenomena.References[1] J.L. Caswell, G.A. Fuller, J.A. Green, A. Avison, S.L. Breen, K.J. Brooks et al., The 6-GHzmethanol multibeam maser catalogue - I. Galactic Centre region, longitudes 345° to 6°, 404(2010) 1029 [1002.2475].[2] G.C. MacLeod, K. Sugiyama, T.R. Hunter, J. Quick, W. Baan, S.L. Breen et al., Detection ofnew methanol maser transitions associated with G358.93-0.03, 489 (2019) 3981[1910.00685].[3] C.L. Brogan, T.R. Hunter, A.P.M. Towner, B.A. McGuire, G.C. MacLeod, M.A. Gurwellet al., 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, 881 (2019) L39[1907.02470].[4] X. Chen, A.M. Sobolev, Z.-Y. Ren, S. Parfenov, S.L. Breen, S.P. Ellingsen et al., New maserspecies tracing spiral-arm accretion flows in a high-mass young stellar object, NatureAstronomy (2020) .[5] R.A. Burns, K. Sugiyama, T. Hirota, K.-T. Kim, A.M. Sobolev, B. Stecklum et al., A heatwaveof accretion energy traced by masers in the G358-MM1 high-mass protostar, NatureAstronomy (2020) 10.[6] B. Stecklum, V. Wolf, H. Linz, A. Caratti o Garatti, S. Schmidl, S. Klose et al., Infraredobservations of the flaring maser source G358.93-0.03. SOFIA confirms an accretion burstfrom a massive young stellar object, 646 (2021) A161 [2101.01812].[7] S.L. Breen, A.M. Sobolev, J.F. Kaczmarek, S.P. Ellingsen, T.P. McCarthy andM.A. Voronkov, Discovery of Six New Class II Methanol Maser Transitions, Including theUnambiguous Detection of Three Torsionally Excited Lines toward G 358.9310.030, 876(2019) L25 [1904.06853].[8] O.S. Bayandina, C.L. Brogan, R.A. Burns, X. Chen, T.R. Hunter, S.E. Kurtz et al., AMultitransition Methanol Maser Study of the Accretion Burst Source G358.93-0.03-MM1,163 (2022) 83 [2201.12075].2https://www.eaobservatory.org/jcmt/science/large-programs/transient/3https://radio.kasi.re.kr/kava/large_programs.php#sh35

Recent updates on the Maser Monitoring Organisation

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Recent updates on the Maser Monitoring Organisation

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