Observing Water Masers

Anita Richards Anita Richards with many others including: with many others including: Masers Masers A. Baudry, J. Brand, S. Etoka, M.D. Gray, F. Herpin, A. Baudry, J. Brand, S. Etoka, M.D. Gray, F. Herpin, E.E. Lekht, B. Pimpanuwat E.E. Lekht, B. Pimpanuwat VY CMa VY CMa Y. Asaki, R. Humphreys, A. Singh, L. Ziurys Y. Asaki, R. Humphreys, A. Singh, L. Ziurys ATOMIUM ATOMIUM L. Decin, C. Gottlieb, T. Danilovich, K-.T. Wong et al. L. Decin, C. Gottlieb, T. Danilovich, K-.T. Wong et al. Observing water masers and Thank You to Fabrice, Alain and all the organisers of this interesting meeting Mike Peel, JBCA Mike Peel, JBCA Observing water from the ground is easy... ●But seeing through it.... ●Observing windows ●Masers as diagnostics –Beaming ●Precise measurements ●Shocks –Magnetic fields –Multiple lines ●Pumping conditions constrain physical conditions n, T, dV ... Atmospheric transmission ALMA v. good medium VLA good Sea level Water maser lines ALMA v. good medium VLA good Sea level Predicted H2O maser optical depths (Gray+'16) Detected transitions shown as broad lines (some when red-shifted to better transmission) See Gray+'16, Hirota+'18, IAU 336 proc. for detections Telluric absorption worse for low-excitation lines Arrays for 22 GHz ~open access (a) e-MERLIN (UK); 217 km; 1.3 – 23 GHz ●10-mas @22 GHz, hundreds mas largest scales (b) Australia Telescope Compact Array (up to ~100 GHz) (c) VLA (USA); 36 km; <1 – 50 GHz; ●most sensitive at 22 GHz, 100-mas @22 GHz (d) VLBI: VLBA, EVN, global: thousands km ●sub-mas resolution, resolves out flux (e) VLBI: VERA/KVN/KAVA: dual beam/multi-band ●precise astrometry 217 km (a) (c) (d) (e) (b) High frequency arrays (a) NOEMA (France) ●70 – 276 GHz, several 100 mas (b) ALMA (Chile) ● 30 – 950 GHz, ≥5 mas (c) SMA (Hawaii) ●190 – 400 GHz, few 100 mas (c)(b) (a) RadioAstron (Ru) 2011-2017 HALCA (Jp) 1997-2005 22 GHz VLBI space missions m-arcsec Resolution Orion KL cloud overlap flare Millions Jy, Tb > 1016 K Kobayashi+'00, Matveyenko+'17 ●Event Horizon Telescope –200 – 370 GHz –No maser observations yet (?) Sun-sized maser spots in SFR Cep A Sobolev+'18 Single dishes: H2O masers & monitoring ●22 GHz –≥100m: Effelsberg (De), GBT (USA) most sensitive –30 – 100m: Yebes (Es), Medicina, SRT (It), Murriyang (Parkes) (Au) –20 – 30m: Onsala (Se), Metsahovi (Fi), Pushchino (Ru), Hartrao (Za, uncooled), individual KVN and other array dishes, ● High frequency –IRAM 30-m (Es) 73 – 375 GHz –JCMT (Hawaii) 211 – 375 GHz –APEX (Cl) 175 – 850 GHz –SMT (USA) 205 – 720 GHz –LMT (Mx) 84 – 280 GHz ●Above the atmosphere.... –SWAS, KAO e.g.380 GHz Phillips+'80 –Herschel e.g. 620 GHz Harwitt+'10 –THz masers Herschel, SOFIA e.g. Neufeld+'17, Herpin+'17 –High-resolution space-borne astronomy ed. Gurvits&Falcke 2020 Dusty Molecular Cloud Black hole or Neutron star Planetary Nebula White dwarf Red Supergiant Betelgeuse HL Tau b Small star e.g. Sun AGB (Mira) star & wet, dusty clouds H i g h - m a s s s t e l l a r e v o l u t i o n L o w - m a s s s t e l l a r e v o l u t i o n Dust and light (CHONPS) elements Iron, heavy elements Iron, heavy elements Massive star Massive star Alderamin Alderamin Protostar+planet Supernova Supernova remnan remnant in t in M82 M82 L s s 22-GHz velocity channels S Per 22 GHz ●Fit components size s in successive velocity channels –e.g. A, B, E above Radially Radially expanding expanding stellar wind stellar wind B ●Pos.-vel. gradient gives parent cloud size L Maser clouds ●S Per H2O maser structure in velocity channels ●~half S Per features last 5 yrs + ●Feature A rotated at ~sound speed –VLSR close to V✷ –non-linear motion away from star ●B radial proper motion –radial acceleration in VLSR V✷ -38.5 km/s ●A, B masers fade/reappear over 5 years –Masers blink, clouds survive ●Similar survival timescales round other RSG A B colour MERLIN black Pushchino S Per Cloud size depends on star size ●Cloud radius ~1R✷ –Ten-fold range of R✷ –Assuming radial expansion, birth radius 5%–10% R✷ ●Must be determined by stellar properties –Not dust cooling/ microphysics ●Would be same scale for all ✷'s –Star spots? –Convection cells? Richards et al. 2012 Shrinking of brighter masers ●Component size s ●Intensity Iν ●Brighter spots are smaller s ∝ 1/sqrt [ln(Iν)] S Per L s s ●~Spherical clouds ●“Amplificationbounded” maser ●Beaming angle s/L ≲ 0.1 radian s (au) 10 1 5 6 7 8 9 10 Iν S Per Cloud size Richards+2011 Elitzur+1992 Brighter=bigger: shock diagnostic U Ori ●Shock 'into page' –Maser propagation perpendicular ●Pump photons escape orthogonally ●Emission amplified over full width ●“Matter bounded” beaming ●Apparent size ~ actual size ●Need resolution few 10s mas or less ●Sensitivity to large(~100s) mas scales 5 6 7 8 9 10 Iν s (au) 10 14 epochs S Per RSG 2.3 kpc well-filled 22 GHz shell S Per RSG 2.3 kpc well-filled 22 GHz shell U Ori Mira 266 pc sparser 22 GHz shell S Per approx. relative physical sizes U Ori S Per RSG 2.3 kpc well-filled 22 GHz shell U Ori S Per U Ori deeper, faster pulsations than S Per Maser properties reveal wind disturbances Richards Elitzur & Yates 2010 Elitzur Hollenbach & McKee 1992 ●Distinguish between smoothly expanding regions and those affected by pulsations –e.g. U Ori thinner-shelled Mira V. S Per thick-shelled RSG ●Pulsation shocks affect more of U Ori 22-GHz shell –Need to detect ~all the emission ●e-MERLIN 22 GHz H2O OK Different masers – different conditions ●MERLIN H H2 2O O masers 22 GHz ●EVN/Global VLBI 1.6 GHz OH OH mainline mainline masers masers –Interleave H2O ●Extended OH resolved-out ●H2O maser clumps n~1015 m-3 ●T ~ 400 – 1000 K ●OH mainlines n~1014 m-3, lower end of T range –Cooler, less dense interclump gas Multiple mm-sub-mm wave water masers ~10 so far mapped out of dozens 20 10 0 13 15 17 log(n) m-3 where n is number density, assuming XH2O (fractional H2O abundance) 4e-5; Tdust 50 K except for 268 GHz, 1025 K (Gray+ 2016, Baudry+2022) Tk(K) 2500 1500 500 Maser t 22 GHz 183 GHz 250 GHz 268 GHz 321 GHz 325 GHz 658 GHz E EU U 643 643 K 200 K 6141 K 6039 K 1861 K 454 K 2360 K White lines: loci of predicted conditions in RSG CSE ●658 658, , 321 321, , 325 325 GHz ●Deeper shade = stronger maser τ ●Also for 22 22, , 183 183 GHz contour at 50% max τ ●Lowest contour τ at sensitivity limit ●Overlap/segregation constrains physical conditions 263 GHz 4475 K like 250 & 268 260 GHz 3954 K like 268 Clump overlap ●Coincidence within clump extents ●Constrain conditions on few-au scales ●Work in progress! ALMA Tracing the Origins of Molecules In dUst forMing winds PIs Leen Decin (KU Leuven, Be), Carl Gottlieb (CfA, USA) et al. ●~20-mas, ~1 km/s resolution survey from 214-270 GHz –17 O-rich Asymptotic Giant Branch and Red Supergiant stars –Dozens (mostly thermal) lines, 25+ molecules (Wallstrom+2023) –Ten H2O lines detected (Baudry et al. 2023), mostly thermal GHz 222 252 254 260 263 267 268 H2O lines maser Baudry+2023 Water in Atomium ●10 lines detected –9 new –R Hya all lines ●222 – 268 GHz –Eup 3110 – 6264 K ●268-GHz –All O-rich stars, much masing –Some 260, 263GHz masing Baudry+'23 S Pav 263 GHz S Pav 263 GHz VX Sgr 263 GHz VX Sgr 263 GHz S Pav 263 GHz S Pav 263 GHz S Pav 268 GHz S Pav 268 GHz R Hya 263 GHz R Hya 263 GHz R Hya 268 GHz R Hya 268 GHz IRC+10011 263 GHz IRC+10011 263 GHz IRC+10011 268 GHz IRC+10011 268 GHz VX Sgr 268 GHz VX Sgr 268 GHz ●Mostly within few – ten R✸ ●More extended for high mass loss rates? (Baudry) ●Some thermal absorption against star ●H2O needed for Al oxide nucleation Hoffner+'16, Gobrecht+'22,23 Gottlieb in prep. 174 pc 174 pc 148 pc 148 pc 740 pc 740 pc 1560 pc 1560 pc High-ex lines Water masers at 260, 263, 268 GHz ●Similar distribution, inner few R✸, 268 GHz brightest 263 GHz 268 GHz Optical stellar size ●Original models don't predict 260, 268 GHz at high Tk ●Within ~2 R✸ magnetic field strong (many mG to G)? –Shock compression similar to VY CMa where 268 GHz is seen? VX Sgr all 3 masers Plenty of time for reactions in inner few R✸ 3.5 R✸ 7.7 au 2 R✸ R✸ 12.6 mas (2.2au) Weigelt+’00 38 epochs SiO maser proper motions Local |V✸ – Vclump| up to ~ 10 km/s Assaf '17 Mira R Cas ●Mean proper motion ~0.4 km/s away from ✸ in plane of sky ●Net Vexp ≲0.55 km/s ●Wind takes 45 – 70 yr to go 3.5 R✸ –Also Cho+'24 SiO-H2O progression Post-AGB 'Water Fountains' ●W43A H2O maser bipolar outflow proper motions –OH torus ●22-GHz polarization –Magnetic collimation Vlemmings, Imai, Diamond ●FLASHING project –Nobeyama monitoring, KAVA imaging –12 water fountains ●Incl. fastest-known ejecta decelerating from 300 km/s Imai+'23 IRAS 18286-0959 Imai+2020 Star formation ●Orion KL: Massive protostar driving NE-SE outflow –336-GHz masers trace ~100-au disc enclosing >7 M⊙ –SiO traces disc wind Hirota et al. 2014 See last talk also: Facchini VERA ALMA 22-GHz global VLBI − 0.07 au region − Maser Tb 1017 K Matveyenko et al. 2004 Water filament tracing cloud collision? ●S128 SFR - ~17 kpc from Gal. centre -Interaction of CO clouds? ●H2O imaged in 1998, 99 ●900-AU filament with parallel companion -15 km/s velocity dispersion -Apparent 'proper motion' 100 km/s: pattern speed? ●Traces CO cloud collision shocks? - Suggested by fractal clustering scales Fractal scales, Shocks and Turbulence •Direct measurements of turbulence: –Line width fluctuations –Maser proper motions •Fractal scales –Incompressible/ Kolmogorov within clumps –Shallower slope on larger scales suggests supersonic dissipation ●Need full range of scales –Strelniski+'02, Silant'ev+06, Gray'12 SFR S128A (22 GHz) –Richards, Lekht+'04