The fountain of the luminous infrared galaxy Zw049.057 as traced by its OH megamaser

A&A, 689, A163 (2024) h ps://doi.o g/10.1051/0004-6361/202450065 c The Au ho s 2024 As onomy & As ophysics The oun ain o he luminous in a ed galaxy Zw049.057 as aced by i s OH megamase Boy Lankhaa 1,2,?, Susanne Aal o1, Cla e We he s1, Ja ie Moldon3,4 , Rob Beswick4, Ma k Go ski1, Sabine König1, Chen ao Yang1, Je Mangum5, John Gallaghe 6,7 , F ançoise Combes8, Dimi a Rigopoulou9,10, Edua do González-Al onso11, Sébas ien Mulle 1, Ismael Ga cia-Be ne e9, Ch is ian Henkel12, Yu i Nishimu a13 , and Claudio Ricci14,15 1Depa men o Space, Ea h and En i onmen , Chalme s Uni e si y o Technology, Onsala Space Obse a o y, 439 92 Onsala, Sweden 2Leiden Obse a o y, Leiden Uni e si y, Pos O ice Box 9513, 2300 RA Leiden, The Ne he lands 3Ins i u o de As o ísica de Andalucía, Glo ie a de la As onomía, s/n, 18008 G anada, Spain 4Jod ell Bank Cen e o As ophysics, Depa men o Physics and As onomy, The Uni e si y o Manches e , Manches e M13 9PL, UK 5Na ional Radio As onomy Obse a o y, 520 Edgemon Road, Cha lo es ille, VA 22903, USA 6Wisconsin IceCube Pa icle As ophysics Cen e , Madison, WI 53703, USA 7Depa men o Physics and As onomy, Macales e College, 1600 G and A e, S . Paul, MN 55105, USA 8Obse a oi e de Pa is, LERMA, Collège de F ance, CNRS, PSL Uni e si y, So bonne Uni e si y, Pa is, F ance 9As ophysics, Depa men o Physics, Uni e si y o Ox o d, Keble Road, Ox o d OX1 3RH, UK 10 School o Sciences, Eu opean Uni e si y Cyp us, Diogenes S ee , Engomi, 1516 Nicosia, Cyp us 11 Uni e sidad de Alcalá, Depa amen o de Física y Ma emá icas, Campus Uni e si a io, 28871 Alcalá de Hena es, Mad id, Spain 12 Max-Planck-Ins i u ü Radioas onomie Au dem Hügel 69, 53121 Bonn, Ge many 13 Depa men o As onomy, The Uni e si y o Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo 113-0033, Japan 14 Ins i u o de Es udios As o ísicos, Facul ad de Ingenie ía y Ciencias, Uni e sidad Diego Po ales, A . Ejé ci o Libe ado 441, San iago, Chile 15 Ka li Ins i u e o As onomy and As ophysics, Peking Uni e si y, Beijing 100871, China Recei ed 22 Ma ch 2024 /Accep ed 4 June 2024 ABSTRACT High- esolu ion (000 .037−000 .13 [10−35 pc]) e-MERLIN (λ6−18 cm) and (000 .024 [6.5 pc]) ALMA (λ1.1 mm) obse a ions ha e been used o image OH (hyd oxyl) and H2CO ( o maldehyde) megamase emission, and HCN 3 →2 emission owa d he nuclea (<100 pc) egion o he luminous in a ed galaxy Zw049.057. Zw049.057 hos s a compac obscu ed nucleus (CON), and hus ep esen s a class o galaxies ha a e o en associa ed wi h in low and ou low mo ions. Fo maldehyde megamase emission has been de ec ed owa d he nuclea egion, .30 pc (000 .1), and aces a s uc u e along he disk majo axis. OH megamase (OHM) emission has been de ec ed along he mino axis o he disk, ∼30 pc (000 .1) om he nucleus, whe e i exhibi s a eloci y g adien wi h ex ema o −20 km s−1 sou heas (SE) o he disk and −110 km s−1no hwes (NW) o he disk. HCN 3 →2 emission e eals ex ended emission, along he disk mino axis ou o ∼60 pc (000 .2). Analysis o he mino axis HCN emission e eals high- eloci y ea u es ex ending ou o 600 km s−1, edshi ed on he SE side and blueshi ed on he NW side. We p opose ha he high- eloci y HCN emission aces a as (>250 km s−1) and collima ed ou low ha is en eloped by a wide-angle and slow (∼50 km s−1) ou low ha is aced by he OHM emission. Analysis o he ou low kinema ics sugges s ha he slow wide-angle ou low will no each escape eloci y and will ins ead all back o he galaxy disk, e ol ing as a so-called oun ain low, while he as collima ed ou low aced by HCN emission will likely escape he nuclea egion. We sugges ha he absence o OHM emission in he nuclea egion is due o high densi ies he e. E en hough OHMs associa ed wi h ou lows a e an excep ion o con en ional OHM emission, we expec hem o be common in CON sou ces ha hos bo h OHM and H2CO megamase s. Key wo ds. mase s – ISM: je s and ou lows – galaxies: e olu ion – galaxies: ISM – galaxies: kinema ics and dynamics – galaxies: nuclei 1. In oduc ion The majo i y o he mos luminous galaxies adia e he bulk o hei ene gy in he a -in a ed (FIR, Sande s & Mi abel 1996). Acco ding o hei luminosi y, hese a e ei he classi ied as luminous (LIR >1011 L) in a ed galaxies (LIRGs), o ul a- luminous (LIR >1012 L) in a ed galaxies (ULIRGs). The ?Co esponding au ho ; [email p o ec ed] ex eme luminosi ies o (U)LIRGs a e powe ed by an ac i e galac ic nucleus (AGN), an in ense s a bu s (SB) phase, o bo h. (U)LIRGs emi he bulk o hei ene gy in he FIR as hei luminosi y sou ces a e embedded in a dus y phase ha ep ocesses adia ion o longe wa eleng hs. While (U)LIRGs ep esen an e olu iona y phase ha many galaxies go h ough (e.g. Smail e al. 1997;Hughes e al. 1998), hey hemsel es a e apidly e ol ing objec s. Open Access a icle, published by EDP Sciences, unde he e ms o he C ea i e Commons A ibu ion License (h ps://c ea i ecommons.o g/licenses/by/4.0), which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in any medium, p o ided he o iginal wo k is p ope ly ci ed. This a icle is published in open access unde he Subsc ibe o Open model.Subsc ibe o A&A o suppo open access publica ion. A163, page 1 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) A signi ican ac ion o (U)LIRGs hos compac ( < 100 pc), highly obscu ed (NH2&1025 cm−2), and wa m (T& 100 K) nuclei (Aal o e al. 2015b;Fals ad e al. 2019,2021; Ga cía-Be ne e e al. 2022;Donnan e al. 2023). These compac obscu ed nuclei (CONs) a e esponsible o a la ge ac ion o he o al in a ed luminosi y o hei hos galaxies, despi e hei small sizes (González-Al onso e al. 2012;Fals ad e al. 2015,2021). Due o hei opaque na u e, i is di icul o dis- ce n he ul ima e sou ce o hei luminosi y. I has become inc easingly clea ha he CONs ep esen an e olu iona y phase ha is associa ed wi h bo h in lowing (González-Al onso e al. 2017;Aal o e al. 2019;Fals ad e al. 2019) and ou lowing (Ba cos-Muñoz e al. 2018;Fals ad e al. 2018;Go ski e al. 2023;We he s e al. 2024) gas mo ions. Ye , due o hei opaque- ness, signa u es o adial gas mo ions a e o en only disce nible a wa eleng hs &1 mm (Fals ad e al. 2019). Radial gas mo ions owa d galaxy nuclei a e decidedly impo an o unde s anding galaxy e olu ion. In lowing gas mo ions d i e nuclea ac i i y and eed he nuclea s a - o ming gas. In u n, ou lows anspo he chemically en iched nuclea gas and dus away om he nuclea egion, owa d galaxy halos and he in e galac ic medium (Veilleux e al. 2020;Ma in 2005), bu also may con ibu e o nuclea g ow h by e icien ly anspo ing angula momen um (Wada 2012;Konigl & Ka je 1994). Galac ic ou lows may be d i en by nuclea ac i i y, s el- la winds and supe no ae om he SB phase, adia ion p essu e, o cosmic- ay p essu e (Veilleux e al. 2020). Indeed, he asso- cia ion o CONs wi h adial gas mo ions indica es ha hese sou ces a e apidly e ol ing (Sakamo o e al. 2013). Unde - s anding hese gas mo ions and cons aining hei d i ing mech- anism(s) is o pi o al impo ance o unde s anding CONs, bo h as a subclass o (U)LIRGs, as well as hei indi idual ela ions wi h hei hos galaxies. In his wo k, we s udy gas kinema ics owa d he galaxy Zw049.057 (IRAS 15107+0724). Zw049.057 is a LIRG, wi h a luminosi y o LIR =1.8×1011 L, loca ed ([RA, Dec] (J2000) =[15:13:13.10 +07:13:32.0]) a an es ima ed dis ance o 56 Mpc (Sande s e al. 2003), and hos s a CON (Aal o e al. 2015b;Fals ad e al. 2021). We adop a edshi o z=0.01299, which co esponds o a sys emic eloci y o 3897 km s−1 (Ka ge e al. 1998). Th oughou his pape , he op ical eloc- i y con en ion is used wi h espec o he ba ycen ic e e ence ame. I is an OHM galaxy (Baan e al. 1987;McB ide e al. 2013), wi h e idence o in lows (Fals ad e al. 2015) and ou - low s uc u es (Baan e al. 1987;Fals ad e al. 2018), hea ily obscu ed in he nuclea egion (Fals ad e al. 2019). The majo axis o he nuclea disk has a posi ion angle o PAmaj =210◦ (Fals ad e al. 2018). We p esen ALMA obse a ions o he HCN J=3→2 emission, ha show signa u es o a col- lima ed ou lowing s uc u e, and e-MERLIN obse a ions o OHM and H2CO ( o maldehyde) emission owa d Zw049.057. We ind e idence ha he OHM emission is associa ed wi h an ou low s uc u e, while popula ion in e sion, and hus he OHM emission, is supp essed in he nuclea disk egion. OH megamase s a e hos ed by (U)LIRGs, whe e hey a e commonly aken o ep esen a compac and in ense mode o s a o ma ion, ha is likely igge ed by idal densi y enhance- men s due o me ge e en s (Da ling 2007;Da ling & Gio anelli 2002). The pic u e o Da ling (2007) is indeed consis en wi h modeling e o s (Pa a e al. 2005;Locke & Eli zu 2008) as well as p e ious high-angula - esolu ion imaging o he mo e luminous OHM using Ve y Long Baseline In e e ome- y (VLBI) ins umen s (Lonsdale e al. 1998;Pihls öm e al. 2001;Richa ds e al. 2005). This pic u e, hough, is in en- sion wi h he associa ion o OHM wi h an ou low s uc u e; a ea u e o OHM ha has been iden i ied in an inc easing numbe o sou ces (Baan e al. 1987,1989;Gowa dhan e al. 2018). We explo e his ension in de ail by compa ing esol ed e-MERLIN imaging o he H2CO megamase o Zw049.057 wi h he eslo ed imaging o he OHM, and analyzing hei (dis)associa ion on he basis o p e ious exci a ion model- ing ( an de Wal e al. 2007; an de Wal & M ulwane 2022; Locke & Eli zu 2008), as well as he eme ging pic u e o he inne dynamics o CON egions (Aal o e al. 2012;Fals ad e al. 2019,2021;Go ski e al. 2023). This pape is s uc u ed as ollows. In Sec ion 2, we p esen he obse a ional se ups ha we e used. In Sec ion 3, we desc ibe he esul s o ou obse a ions. In Sec ion 4, we discuss ou esul s, in which we lay emphasis on he ou low dynamics, as well as he implica ion o ou esul s o he class o OH mega- mase s. We p esen ou conclusions in Sec ion 5. 2. Obse a ions 2.1. e-MERLIN obse a ions Zw049.057 was obse ed wi h he e-MERLIN a ay be ween Janua y 7-14, 2019 in he L-band (p ojec code CY7222) and Janua y 7-8, 2018 in he C-band (CY6203). Obse a ions included all e-MERLIN Telescopes, excep he Lo ell Tele- scope (six elescopes in o al). L-band obse a ions we e co - ela ed in o eigh 64-MHz wide spec al windows spanning a o al equency ange o 1245–1757 MHz. A C-band obse a- ions encompassed 4488–5000 MHz, co ela ed in o ou spec- al windows. A o al o 17.25 and 14.8 hou s o obse a ions we e used a L-band and C-band, espec i ely. Co ela o s we e se o he C-band 4829 MHz H2CO JKaKc= 110-111- ansi ion and o he L-band 1667 and 1665 MHz OH ansi ions. The lux calib a o was 3C286 and he baseline cali- b a o OQ208 o bo h se s o obse a ions. Nea by gain calib a- o s 1516+0701 and 1513+0713 we e used in he Land Cbands, espec i ely. Da a we e ini ially p ocessed using NRAO’s casa (Bean e al. 2022) using he e-MERLIN pipeline1(Moldon 2021), which applies lagging, delay and bandpass calib a ion, and calcula es phase and equency-dependen ampli ude gain co ec ions. Following ini ial calib a ion obse ing bands cen e ed on he edshi ed equencies o he OH (1665 and 1667 MHz es equency) and H2CO (4830 MHz es e- quency) lines we e ex ac ed and imaged o o m indi idual spec al line cubes o u he analysis. The syn hesized beams a e 000 .11 ×000 .039 (30 ×11 pc) o he H2CO obse a ions and 000 .26 ×000 .13 (70.6×35.3 pc) o he OH obse a ions. The esul ing da a ha e a sensi i i y o 0.2 mJy pe beam in a 64 km s−1(1 MHz) channel wid h (H2CO) and 0.77 mJy pe beam in a 20 km s−1(0.11 MHz) channel wid h (OH). 2.2. ALMA obse a ions Obse a ions we e ca ied ou wi h 42 an ennas in he a ay con- igu a ion C43-9/10, wi h p ojec ed baselines be ween 92 m and 13.8 km, on Augus 28, 2021. The on-sou ce in eg a ion ime was 34 minu es unde ela i ely good a mosphe ic condi ions (amoun o p ecipi able wa e apo PWV ∼0.5 mm). 1h ps://gi hub.com/e-me lin/eMERLIN_CASA_pipeline A163, page 2 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) The bandpass esponse o he indi idual an ennas was de e - mined om he quasa J1550+0527. The quasa J1521+0420 was obse ed egula ly o gain calib a ion. The absolu e lux scale was calib a ed using he quasa J1550+0527. The lux den- si y o J1550+0527 was aken om he ALMA lux calib a o da abase. The co ela o was se up o co e ou spec al windows in Band 6. The i s wo spec al windows we e assigned o he uppe side band, wi h bandwid hs o 1.875 GHz and a spec al esolu ion o 7.8 MHz, o co e he HCO+J=3→2 and ib a- ionally exci ed HCN J=3→2ν2=1 lines (spec al window cen e ed a a sky equency 264.3 GHz) and he HCN J=3→2 line in he g ound ib a ional s a e (spec al window cen e ed a 262.5 GHz). Two addi ional 2-GHz wide spec al windows we e assigned o he lowe side band, wi h a coa se spec al esolu- ion o 31.25 MHz, o sample he con inuum emission. All o he ALMA Band 6 obse a ions o Zw049.057 will be published in an upcoming pape by We he s e al. (p i . comm.). He e, we p esen some esul s on HCN J=3→2. The syn hesized beam is 000 .027 ×000 .024 (7.33 ×6.52 pc), whe e B iggs weigh ing was used, adop ing a obus pa ame e o 0.5. The esul ing da a ha e a sensi i i y o 0.26 mJy pe beam in a 20 km s−1(18 MHz) channel wid h. 3. Resul s 3.1. L band con inuum The Lband con inuum a ound 1.67 GHz (λ18 cm) was de ec ed owa d he nuclea egion o Zw049.057; a con ou map is gi en in Fig. 1d. Con inuum emission was ound o exhibi ex ended ea u es in he di ec ion oughly pe pendicula o he nuclea disk majo axis, wi h a posi ion angle o PAC ex en.=120◦. The maximum lux densi y was obse ed as 21.5±0.4 mJy beam−1. We used he Rayleigh-Jeans law o ob ain a co esponding b igh ness empe a u e o 3.25 ×105K. The spa ially in e- g a ed o al lux densi y owa d he nuclea egion was Sν= 41.4±4 mJy, which can be compa ed o A ecibo single dish obse a ions ha e ie e an 18 cm con inuum lux o 40 ± 5 mJy (Baan e al. 1987). Hal o he o al con inuum emission emana es om an (angula ) a ea o 0.05 a csec2(60 pc2). We no e ha his a ea is e y simila o he a ea o emi ance o 33 GHz con inuum adia ion, A33 GHz =0.031 a csec2, as has been ound by Song e al. (2022). 3.2. OH megamase (OHM) OHM emission was de ec ed owa d he nuclea egion o Zw049.057 in bo h he 1.667 GHz and he 1.665 GHz ansi ions. Fo he main mase ansi ion a 1.667 GHz, we e ie ed an in e- g a ed o al lux o 2.0±0.4 Jy km s−1, while o he sa elli e mase ansi ion a 1.665 GHz, we e ie ed 1.0±0.2 Jy km s−1. The o al in eg a ed lux o he 1.667 GHz mase compa es well o Baan e al. (1987), who ind 2.25 Jy km s−1and McB ide e al. (2013), who ind 2.45 Jy km s−12. The in eg a ed o al lux co e- sponds o an OH luminosi y o LOH =10.1L. Figu e 1e shows he momen 0 map o he 1.667 GHz OHM emission. OHM emission is obse ed nea he mino axis, wi h maximal emis- 2We no e McB ide e al. (2013) epo an in eg a ed lux 4.9 Jy km s−1. Howe e , as explained in McB ide e al. (2013) hey use a di e en de - ini ion o he o al lux densi y esul ing in a ac o wo inc ease in he epo ed lux densi y compa ed o commonly used de ini ions including hose used in his pape . Fo a deepe discussion su ounding his opic, we e e o Robishaw & Heiles (2021). sion appea ing abou 000 .2 (∼57 pc) om he 18 cm con inuum peak. The emission o he wes o he con inuum peak appea s s onge , compa ed o he emission o he eas o he con inuum peak. Emission owa d he nucleus, as well as along he majo axis, is unde ec ed. The momen 1 map o he 1.667 GHz OHM emission, gi en in Fig. 1 shows a clea eloci y g adien , om −20 km s−1in he eas , o −100 km s−1in he wes (co espond- ing o abou 5 spec al channels). Wi hin he no hwes (NW) OHM ea u e, a eloci y g adien om he no h o he sou h is obse ed, bu we no e ha his ea u e occu s on a scale smalle han he beam size. The eloci y dispe sion, aken as he squa e oo o he momen 2 map o he 1.667 GHz OHM emission, gi en in Fig. 1g, appea s cons an a ound 70 km s−1 h oughou he OHM egion. Imaging o he 1.665 GHz ansi ion is gi en in Fig. A.2. I is eadily appa en ha he NW ea u e o he OHM main line is also ound o he weake 1.665 GHz mase line; he momen 0 image shows a ea u e a a simila posi ion, while he momen 1 map shows a simila eloci y ield compa ed o he main mase ansi ion a 1.667 GHz. We do no de ec he sou heas (SE) ea- u e o he OHM emission. We asc ibe his o sensi i i y e ec s as o he main mase line, his ea u e was also conside ably weake . 3.3. C band con inuum The Cband con inuum a ound 4.8 GHz (λ6.2 cm) was de ec ed owa d he nuclea egion o Zw049.057. In Fig. 1a we display a con ou map o he Cband con inuum. As o he Lband con in- uum, an ex ended s uc u e appea s p esen along he mino axis (P.A. o ∼120◦). The maximum spec al lux densi y we obse ed as 12.0±0.1 mJy/beam, co esponding o a b igh ness empe a- u e o 1.68×105K. We e ie ed an in eg a ed o al lux densi y owa d he nuclea egion ha was obse ed as Sν=25.6±2 mJy, which compa es well o he MERLIN obse a ions o Baan e al. (2017) ha e ie ed 29.72 mJy, as well as he A ecibo obse a- ions o A aya e al. (2004) ha e ie ed 30.8 mJy. Hal o he o al e-MERLIN Cband con inuum emission emana es om an (angula ) a ea o 0.008 a csec2(20 pc). 3.4. H2CO megamase H2CO megamase emission was de ec ed owa d he nucleus o Zw049.057 in he (JKa,Kc→J0 K0 a,K0 c) 11,0→11,1 ansi- ion a 4.83 GHz. Figs. 1b and 1c p esen he momen 0 and 1 maps o he de ec ed emission, while a zoom-in o hese ig- u es can be ound in Fig. A.1. Maximal emission was ound a 1.08 mJy beam−1, co esponding o 1.4×104K. We e ie ed an in eg a ed o al lux o 0.48 ±0.04 Jy km s−1, whe e Baan e al. (2017) inds 0.308 Jy km s−1using MERLIN and A aya e al. (2004) ind 0.283 Jy km s−1using A ecibo. F om he in eg a ed o al lux, we compu ed he co esponding mase luminosi y 7.3±0.6L, which is la ge enough o i o ul ill he h esh- old o be conside ed megamase emission3. Figu e 1b shows he momen 0 map o he 4.83 GHz H2CO emission. H2CO emis- sion is obse ed concen a ed along he majo axis (PA ∼210◦, Fals ad e al. 2018), wi h maximal emission appea ing abou 000 .1 (∼29 pc) NE o he 6.2 cm con inuum peak. Emission o he no h o he 6.2 cm con inuum peak appea s ∼25% s onge han he emission o he sou h o he Cband con inuum peak. The momen 1 map o he emission, shown in Fig. 1c shows a eloc- i y g adien , ed o blue, om no h o sou h. 3Typical galac ic H2CO mase s ha e luminosi ies .10−6L. A163, page 3 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) (a) (b) (c) (d) (e) ( ) (g) (h) (i) (j) (k) (l) Fig. 1: e-MERLIN and ALMA obse a ions owa d he nuclea egion o Zw049.057. (a) e-MERLIN Cband con inuum con ou map. Con ou le els: [−1, 1, 3, 30, 60, 120, 240, 360,. . .]σ, wi h σ=3.56 ×10−5Jy/beam. The dashed con ou co esonds o −1σ. (b,c) H2CO 4.83 GHz emission momen 0 (b) and 1 (c) map o e laid (b) wi h C Band con inuum emission con ou map. (d) e-MERLIN L Band con inuum emission con ou map. Con ou le els: [−1, 1, 3, 6, 12, 24, 48, 96, 384,. . .]σ, wi h σ=7.70 × 10−6Jy/beam. (e, ,g) OH megamase emission (1.667 GHz) momen maps (e, momen 0; , momen 1; g, squa e oo o he momen 2). Images a e o e laid wi h Lband con inuum emission con ou s. (h,i) Momen 0 (h) and momen 1 (i) maps o he HCN J=3→2 emission. In (h), nega i e emission yields (abso p ion) a e pu o ze o. Red line and whi e ma k in (h) indica e he slice and cen e o he p- diag am shown in (j). (k) In eg a ed in ensi y o HCN high- eloci y wings. In eg a ion pe o med be ween eloci ies ±250− ± 750 km s−1(blue/ ed). Con ou le els: [3,4,5, . . .]×33 mJy/beam km s−1. (l) jux aposi ion o he momen 0 maps o H2CO ( ed) and OH (blue) emission. Di ec ions o he adio-je (PAje =130◦), CO ou low (PACO =105◦), and disk majo axis (PAmaj =30◦) a e indica ed by he dashed black line, solid black line, and solid g een line, espec i ely. Di ec ion o he ex ended ea u e in he L-band con inuum (PAL=120◦) is indica ed by he dash-do ed ed line. Spa ial o se s o line emission maps a e wi h espec o posi ion o Lband con inuum maximum. Fi ed beams a e shown in he lowe -le co ne o he image. A163, page 4 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) Table 1: Summa y o he eMERLIN obse a ions. Iν,max (mJy beam−1)(a)Sν(mJy) (b)Rd Sν(Jy km s−1)(c) Lband con . 21.5±0.4 41.4±4 OH 6.50 ±0.77 2.0±0.4 Cband con . 12.0±0.1 25.6±2 H2CO 1.1±0.2 0.48 ±0.04 No es. (a)Maximal lux densi y, (b)Spa ially in eg a ed lux densi y, (c)Spa ially and spec ally in eg a ed lux densi y. 3.5. HCN mino axis emission The HCN J=3→2 ansi ion was de ec ed owa d he nucleus o Zw049.057. An image o he in eg a ed in ensi y is gi en in Fig. 1h. In he inne 50 mas (14 pc) owa d he nucleus, HCN is obse ed in abso p ion, while i is obse ed in emission a he ou om he nucleus. Emission ex ends a he along he mino axis (PA o ∼120◦,Fals ad e al. 2018), compa ed o he majo axis (PA o ∼30◦,Fals ad e al. 2018). We analyzed he eloci y s uc u e o he mino axis emis- sion using a posi ion- eloci y diag am (p- diag am) o a s ong ea u e along he mino axis. The posi ion-slice is pe pendicu- la o he mino axis, and indica ed in Fig. 1h, in which he ze o-o se posi ion is ma ked wi h a blue c oss. The p- dia- g am is plo ed in Fig. 1j. In he diag am, we obse e a ea u e ha p esen s a co ela ed posi ion- eloci y s uc u e be ween −150 o 200 km s−1, and a ea u e ha is associa ed wi h high- eloci y emission >200 km s−1, ex ending o ∼600 km s−1whe e we obse e emission concen a ed a ound he cen al posi ion. We indica ed he high- eloci y ea u e wi h a g een ma k- ing. In e es ingly, he emission o he ea u e be ween −150 o 200 km s−1 ollows he p o ile o a skewed and shi ed ellipse in PV-space. The ellipse, which was i ed by eye, is d awn in dashed blue in Fig. 1j, and is 120 km s−1wide and 120 mas high, shi ed by 40 km s−1, and skewed by a eloci y g adien o 0.5 km s−1mas−1. Finally, we p esen in Fig. 1k an in eg a ed in ensi y image o he high- eloci y (±250 km s−1−±750 km s−1) emission. Bo h he blueshi ed and he edshi ed emission show an emission s uc u e ha is concen a ed along he mino axis, consis en wi h he ea lie discussed p- diag am. We e ie ed an in e- g a ed o al lux o 12.7 Jy km s−1 o he edshi ed high- eloci y emission and 12.5 Jy km s−1blueshi ed high- eloci y emission, bu no e ha he in eg a ed o al lux o he blueshi ed emis- sion may be an o e es ima ion due o con amina ion o he 41,3→31,2me hanimine line ( es equency 266.270024 GHz) a 432 km s−1wi h espec o he HCN 3 →2 es equency. 4. Discussion 4.1. HCN ou low The HCN emission along he mino axis aces wo dis inc s uc u es, as can be eadily asce ained om Fig. 1j. We i s dis- cuss he low eloci y ea u e, indica ed in blue in Fig. 1j. F om he p- diag am, emission could be ex ac ed ha appea ed as a shi ed, skewed ellipse (wid h: 120 km s−1, heigh : 120 mas, shi : 40 km s−1, skew: 0.5 km s−1mas−1) in p- space. We p o- pose ha his ea u e aces a o a ing, wide-angle, and hol- low, ou lowing s uc u e. The skew co esponds o a eloci y g adien (5.7×10−14 s−1=1.8 km s−1pc−1) ha is due o he ou low o a ion. The wid h and shi o he ellipse a e due o emission om he on - and back side o he ou low, wi h a eloci y di ec ed adially om (wid h, 1 2×120 km s−1= 60 km s−1) and along (shi , 40 km s−1), he ou low symme y axis (see Appendix B o Tabone e al. 2020, o modeling o a ans e se p cu o an expanding wind annulus). We consid- e ed he possibili y ha he blue side o he ellip ical s uc u e ep esen s he o a ing nuclea disk, bu uled ou his scena io, as he ellip ical s uc u e is p esen also in mino axis p- slices >200 mas, beyond he HCN disk adius o ∼150 mas. Bo h Figs. 1j and 1k clea ly indica e ha he high- eloci y emission eme ges om a linea and con ined s uc u e. F om i s spa ial and eloci y s uc u e, we in e p e he high- eloci y HCN emission along he mino axis as a as collima ed ou - low. Fo he posi ion angle o he collima ed ou low we ind PAHCN =105◦. In e es ingly, his is he same as he posi ion angle ha Fals ad e al. (2018) ind o he ou low aced by CO J=6→5 emission. Fals ad e al. (2018) ind ha he CO J=6→5 emission ex ends o 400 km s−1, less han he ∼600 km s−1we ind, bu his disc epancy may be due o di e - en exci a ion condi ions o sensi i i y e ec s. We p opose he CO J=6→5 emission, obse ed by Fals ad e al. (2018) and he high- eloci y HCN emission a e acing he same s uc u e. To es ima e he mass o he as collima ed ou low, we ex ac ed i s luminosi y and used he L(HCN) o M(dense) con- e sion ela ion o Gao & Solomon (2004). We no e ha he con e sion ela ion o Gao & Solomon (2004) was de i ed o he HCN 1−0 line; o con e ou HCN 3 →2 luminosi y o an HCN 1−0 luminosi y, we assumed a HCN J=3→2 J=1→0 empe a- u e a io o 0.3 (K ips e al. 2008). Accoun ing only o he ed ou low (12.7 Jy km s−1, 250−500 km s−1), his p ocedu e yields a collima ed ou low mass o MHCN =6.2×107M. We no e ha he con e sion ela ion is de i ed o g a i a ionally bound gas, so he mass will be o e es ima ed i he dense gas is in non sel -g a i a ing clumps. Aal o e al. (2015b) s udied he impac o u bulence on he con e sion ac o and ound ha i should be scaled down by abou a ac o o i e o non sel -g a i a ing gas in he ou low. Because o hese unce ain ies, we adop MHCN =1−6×107Min o de o compu e he ou low kine- ma ics om ou mass es ima es. Fu he mo e, we pu conse a- i e es ima es o ∼250 km s−1and 30 pc o he ou low eloc- i y and size. Combined, we compu e he mass-loss, momen- um, momen um lux, ene gy and ene gy lux o he ou low as: ˙ MHCN =85.2−511 M/y , pHCN =2.5−15 ×109Mkm/s, ˙pHCN =1.3−6.5×1012 L/c,EHCN =0.8−3.9×1055 e gs and ˙ EHCN =0.5−2.7×109L. We no e ha we ha e no included any ene gy con ibu ion om gas dispe sion in ou es ima es o he ou low ene gy. In e ms o he IR luminosi y o Zw049.057, we may pu he momen lux and ene gy lux, ˙pHCN/(LIR/c)≈ 7−34 and ˙ EHCN/LIR ≈0.003−0.015. These a e s ikingly high yields o he momen um and ene gy luxes. Compa ed o he sample o ULIRG ou lows ha González-Al onso e al. (2017) A163, page 5 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) analyzed, whe e ou low momen um and ene gy luxes in he ange o 2−5LIR/cand 0.1−0.3% LIR we e de i ed, bo h he ene gy and momen um luxes o he ou low aced by HCN a e a he highe end, o exceeding, he yields o he ULIRG ou - lows. We discuss his poin in mo e de ail in Sec ion 4.3. 4.2. OHM ou low The OHM spa ial and eloci y s uc u es, showing emission along he mino axis wi h a eloci y g adien o ∼100 km s−1, ed in he SE owa d blue in he NW, a e consis en wi h an ou - lowing s uc u e. We ule ou ha he OHM is exci ed in he disk, as in his scena io maximal emission is expec ed owa d he disk majo axis (Pihls öm e al. 2001;Pa a e al. 2005), opposi e o wha we obse e. Indeed, wi h eloci y dispe sion o he o de o he disk o a ion (Fals ad e al. 2018), he longes , eloci y-cohe en , columns o OH a e expec ed owa d he disk majo axis, while Fig. 1a also shows signi ican seeding adi- a ion o eme ge he e om. Ye no mase emission is obse ed om he disk, leading us o sugges ha popula ion in e sion is supp essed he e. While we canno ule ou ha o a ion con- ibu es o he eloci y p o ile o he OHM ea u es, he obse ed eloci y g adien canno be explained by o a ion alone. Finally, he e idence o ou lowing s uc u es eme ging om he nuclea egion in he HCN emission, including a s uc u e ha has simi- la kinema ical p ope ies as he ea u es aced by he OHM, is addi ional ci cums an ial e idence ha OHM is acing an ou - low s uc u e. Thus, we in e p e he OHM emission as eme g- ing om an ou low s uc u e. We p oceed o make kinema ical es ima es o he OHM ou low. In o de o es ima e he OHM ou low mass, we use he esul ha OHM ope a e a ound OH column densi ies o NOH ∼1017 cm−2(Locke & Eli zu 2008). We de ine he OHM emission egion as he one whe e he spec ally in e- g a ed in ensi y exceeds 0.3 Jy/beam km s−1, which has an angu- la a ea o 0.12 a csec2. Using an abundance o xOH =2×10−6 (González-Al onso e al. 2012,2017) ela i e o H2, and an a e - age pa icle mass o µ=2.3mH, we compu e he OHM ou low mass as MOHM =9×106M. Adop ing an ou low eloci y o 50 km s−1and a size o 30 pc, he mass expulsion a e o he ou - low is ˙ MOHM =15 M/y . Wi h hese es ima es, we compu e he momen um, momen um lux, ene gy and ene gy lux o he ou low as: pOHM =8.8×1046 g cm s−1, ˙pOHM =3.7×1010 L/c, EOHM =2.187 ×1053 e gs and ˙ EOHM =3.1×106L. In e ms o he IR luminosi y o Zw049.057, we may pu he momen lux and ene gy lux, ˙pOHM/(LIR/c)=0.2 and ˙ EOHM/LIR =2×10−6. The OHM ou low eloci y (50 km s−1) is much less han he minimal eloci y equi ed o escape he inne egion ( √2 ci c ≈ 200 km s−1, see, e.g. Ma in 2005). Indeed, as discussed in Sec ion 4.3, he OHM ou low will likely ail o escape he inne egion and will be obscu ed when obse ed in he IR ange o he spec um. Ins ead, he ou low will likely all back on o he gas close o he nuclea egion, causing a signi ican s i ing o he nuclea gas (Aal o e al. 2020;Wada 2012). No only will he nuclea gas be endowed an app eciable amoun o kine ic ene gy in he o m o u bulence, bu he gas s i ing will also impac he acc e ion dynamics signi ican ly, as u bulence is di ec ly ela ed o he e ec i e iscosi y o he gas (Shaku a & Sunyae 1976;P ingle 1981). CON egions a e consis en ly associa ed wi h nuclea gas eloci y wid hs in excess o 100 km s−1. I his is dispe sion, i would imply ha he u bulen kine ic ene gy o he gas a exceeds he he mal ene gy: Ekin/E he m >104. I may he e o e well be possible, a leas locally, ha he con e sion o u bulen ene gy h ough shocks may be a signi ican sou ce o luminosi y. We howe e no e ha he lows may s ill be la gely lamina and ha he high eloci y wid hs a e caused by line o sigh e ec s o a laye ed s uc u e o in- and ou lows. Spec oscopic IR obse a ions, pe o med wi h He schel, a 23 H2O and 12 OH ansi ions, ha e no been able o de ini- i ely indica e he ou low we obse e in he OHM emission (Fals ad e al. 2015). This is pa ially due o esolu ion and he ela i ely low ou low eloci y o he OH gas. Bu , also, and impo an ly, we ind clea e idence ha he OHM emission is exci ed only in he ou lowing gas. Thus e ealing a map o he ou lowing gas ha is ela i ely uncon amina ed by he disk emission. While we p esen he i s esol ed in e e o- me ic maps o OHM in associa ion wi h an ou low, spec al ea u es ha we e o se in eloci y ga e ea ly indica ions in single dish obse a ions o Zw049.057 (Baan e al. 1987) and o he OHM galaxies (Baan e al. 1989). No ably, h ough spec- al analysis, Gowa dhan e al. (2018) we e able o ind s ik- ing e idence o he associa ion o OHM wi h ou lowing gas owa d wo ULIRGs, by combining un esol ed OHM obse a- ions wi h in e e ome ic imaging o CO and CN emission. In Sec ion 4.5.1 we discuss OHM acing ou low s uc u es in ela- ion o hei exci a ion condi ions and o en-obse ed associa ion wi h H2CO megamase s. 4.3. Ou low launching The kinema ic es ima es we p esen ed abo e may help us o cons ain he launching mechanism o he high- eloci y colli- ma ed ou low and he slow wide-angle ou low. Fi s , we con- side he scena io o a adia i ely d i en ou low. Radia ion p es- su e is a momen um conse ing mechanism o launch he ou - lows. We compa e he o al momen um lux o he ou low com- ponen s and ela e i o he momen um lux ha emana es om he nuclea egion. Fo he OHM ou low, we es ima ed ea lie ˙pOHM/(LIR/c)=0.04−0.2, while o he collima ed HCN ou - low, we es ima ed ˙pHCN/(LIR/c)≈7−34. Thus, wi hou a sig- ni ican momen um boos , i is di icul o explain he collima ed HCN ou low wi h a momen um conse ing ou low launching mechanism. I is possible o he wide-angle ou low o be adia i ely d i en. We explo e he hypo hesis ha he slow wide-angle ou - low aced by OHM is adia i ely launched. Fi s , he OHM clumps ha e signi ican column densi ies, which ensu e con in- uum op ical dep hs o o de uni y, e en o long wa eleng hs. Indeed, wi h op ical dep hs τOHM ∼1 a 10 µm (co espond- ing o he maximal speci ic in ensi y o he mal adia ion o ∼300 K), i is a possibili y ha he OHM clumps a e li ed om he CON su ace by he he malized IR adia ion ield. A he ins ance o ou obse a ions, he OHM ou low has a ained a (p ojec ed) eloci y o OHM ≈50 km s−1. I is in e es ing o specula e abou he p og ession o he ou low launching, assum- ing i is adia i ely d i en. I he ou low is o be accele a ed, we equi e he ou wa d o ce on an OHM clump, which is due o he adia ion ield, o exceed he inwa d o ce due o g a - i y. We ollow Heckman e al. (2015) and de ine he ou wa d o ce due o he adia ion ield as Fou =˙p adAc/4π 2, whe e ˙p ad is he adia ion momen um lux, Acis he cloud a ea and is he dis ance om he nucleus. The inwa d o ce due o g a i y we pu a Fin =MOHM 2 ci / , whe e MOHM is he OHM clump mass and ci is i s ci cula eloci y. The c i ical momen- um lux o d i e an OHM clump ou wa ds can be ob ained by equa ing he inwa d and ou wa d o ces and is ˙pc i =2.1× A163, page 6 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) 1011L/c 30 pc  NOHM 3×1022 cm−2 ci c 140 km s−12, adop ing ypical alues o he OHM clumps ha occu in he ou low as we obse e i . In e es ingly, he c i ical momen um lux is simila o LIR/c. This indica es ha i he adia ion is he d i ing agen , he OHM ou - low is no accele a ing. In ac , a e nume ical in eg a ion o he abo e equa ions, adop ing he ci ed ypical alues o he OHM clumps ha occu in he ou low as we obse e i , we ound ha a e ∼4×105yea s, he ou lowing OHM clumps will acqui e a nega i e eloci y, indica ing ha hey will e ol e o all back on o he galac ic disk as a oun ain low (Wada 2012). The collima ed HCN ou low equi es a d i ing mechanism beyond adia ion, due o he high momen um equi emen s. Fi s , he possibili y has been explo ed ha he molecula ou - low o Zw049.057 as aced by CO J=6→5 emis- sion, which is likely he same ou low as aced by he high- eloci y HCN emission, is en ained by a adio je (Fals ad e al. 2018). Indeed, Fals ad e al. (2018) ind ha he adio con in- uum a ound 5.3 GHz shows an ex ended ea u e along he mino axis, and while his possible adio je is no aligned wi h ei he he HCN o he CO ou low ound by Fals ad e al. (2018), i may s ill ha e powe ed hem and de lec ed. Based on he je powe es ima e, ˙ Eje =4.7×109L≈˙ EHCN (Fals ad e al. 2018; Baan & Klöckne 2006;Bî zan e al. 2008), we do no ule ou he ( en a i ely de ec ed) adio-je as a d i e o he dense colli- ma ed ou low, bu we do no e ha ou es ima es o he ene gy lux a e likely lowe limi s, as we ha e no included he eloc- i y dispe sion in he ou low ene gy es ima e, and we use a p o- jec ed eloci y o he ou low eloci y. Al e na i ely, he molec- ula ou low ha we obse e can be en ained by an ene gy d i en AGN wind (Silk & Rees 1998;Aal o e al. 2012,2015a). I his is he case, we expec he collima ed ou low o be asso- cia ed wi h an ionized and ho wind. In addi ion, in o de o he molecula ma e ial no o be dis up ed by he en ainmen , apid adia i e cooling and/o s abilizing magne ic ields a e equi ed (Coope e al. 2009;McCou e al. 2015;Leaman e al. 2019). The p ojec ed ou low eloci y o he dense collima ed ou - low aced by HCN was pu a >200 km s−1, wi h maximal p ojec ed eloci ies app oaching 650 km s−1. These ou low eloci ies a e com o ably la ge han √2 ci c ≈200 km s−1, sug- ges ing ha his ou low will escape he nuclea egion. Ou low eloci ies in excess o 3 ci c ≈420 km s−1a e equi ed o escape he galaxy (Ma in 2005), which hus appea s o be he a e o a signi ican ac ion o his ou low. I has been sugges ed ha he mo phology and kine- ma ics o CON egions esemble he p o os ella en i on- men (Aal o e al. 2020;Go ski e al. 2023). In p o os ella egions, ou lows a e hough o be launched magne ocen- i ugally (Bland o d & Payne 1982;Pelle ie & Pud i z 1992; Wa dle & Koenigl 1993;Sp ui 1996;Tabone e al. 2020), and magne ically collima ed. The ou low akes he appea ance o a as collima ed je -like s uc u e, eme ging om he inne launching egions, while owa d he ou e launching egions, a wide( )-angle and lowe eloci y ou low eme ges (Sp ui 1996; Tabone e al. 2020). Such an appea ance is bo h consis en wi h he dynamics and chemis y we ind o ou ou lows, bu we no e ha his mechanism ope a es mos e ec i ely when gas lows a e lamina and c i ically depends on he p esence o an o de ed magne ic ield. Magne ic ields in cool molecula gas may ei he be p obed h ough dus pola iza ion obse a ions (Ande sson e al. 2015), o h ough spec al line pola iza ion, ei he h ough he Zee- man e ec (C u che e al. 1993;Lankhaa & Teague 2023) o h ough he Gold eich-Kyla is e ec (Gold eich & Kyla is 1981; Lankhaa & Vlemmings 2020). Un o una ely, con inuum emis- sion is hea ily a ec ed h ough sel -abso p ion and sca e ing e ec s in bu ied egions (González-Al onso & Sakamo o 2019), e en a (sub)millime e wa eleng hs. Wi h OHM acing he ou - low, obse a ion o i s ci cula pola iza ion would lead o con- s ain s on he magne ic ield in hese egions. Such ex agalac ic Zeeman obse a ions o OHM ha e been pe o med p e iously (Robishaw e al. 2008), on a sample o OHM sou ces exhibi - ing s ong emission. Fo he Zw049.057 OHM, wi h i s mod- es in ensi y yields, Zeeman obse a ions will equi e e y deep in eg a ion, which would be beyond easibili y o he cu en adio elescopes, bu may become possible wi h he nex gene - a ion o adio obse a o ies such as he SKA. Al e na i ely, i may be possible o a ain magne ic ield in o ma ion owa d he nuclea egion h ough linea pola iza ion obse a ions o ib a- ionally exci ed HCN emission, which is known o be luminous (Fals ad e al. 2021) and expec ed o be signi ican ly pola ized due o i s adia i e exci a ion (Lankhaa & Vlemmings 2020; Lankhaa e al. 2022). 4.4. Inne dynamics o Zw049.057 Based on he spa ial and eloci y signa u es o he H2CO mega- mase , OH megamase and HCN emission, as well as cons ain s om exci a ion modeling ha we discuss in Sec ion 4.5.1, we p opose he ollowing model o he dense gas su ounding he nucleus o Zw049.057. Fig. 2p esen s a ca oon o he dense gas su ounding he nucleus o Zw049.057. In his model he H2CO megamase is acing he nuclea disk4. The OH megamase is no exci ed owa d he nuclea disk, bu a he , we p opose, in a wide-angle and slow mo ing ou low s uc u e. The OHM ou - low en elopes a dense , as e , and collima ed ou low ha is aced by high- eloci y HCN emission. This is likely he same ou low ha Fals ad e al. (2018) de ec ed in CO J=6→5 emission a lowe esolu ion. As discussed in Sec ion 4.3, we es ima e ha he dense collima ed ou low has likely a ained su icien eloci y o escape, a leas , he nuclea egion. In con as , he wide-angle ou low aced by he OH megamase does no possess su icien eloci y o escape he nuclea egion. Ins ead, we expec he wide-angle ou low o be d awn back o he nuclea disk a e ∼1 My o o m a so-called oun ain low (Wada 2012). 4.5. OH megamase s 4.5.1. OH megamase exci a ion I is in e es ing o compa e ou obse a ions o he 1.667 GHz OHM o exis ing obse a ions o OH owa d Zw049.057. Fals ad e al. (2018) obse ed he OH 4.660 GHz, 4.766 GHz and 4.751 GHz hype ine ansi ions in abso p ion owa d he nucleus o Zw049.057. O hese ansi ions, he 4.751 GHz is he main hype ine ansi ion, while he ansi ions a 4.660 GHz and 4.766 GHz a e sa elli e hype ine ansi ions. The ela i e in ensi ies o hese h ee hype ine ansi ions a e (4.660:4.751:4.766) GHz =(1:2:1) in he op ically hin limi , 4Ou imaging o H2CO mase emission owa d Zw049.057 ag ees e y well wi h he imaging pe o med by Baan e al. (2017) using MER- LIN. Ye , Baan e al. (2017) ind o o he H2CO megamase galaxies o he con igu a ions o H2CO mase emission, which does no seem o be exclusi ely acing he nuclea disk. In he absence o in e e ome - ic da a o a la ge sample o H2CO megamase galaxies, we do no in end o make he gene al claim ha H2CO megmase emission aces he nuclea disk o he hos galaxy. A163, page 7 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) FMM OHM La ge scale adio je Fig. 2: Ca oon o nuclea sys em o Zw49.057. The collima ed dense ou low ha is aced by he high- eloci y HCN emission is indica ed wi h dashed ed and blue a ows. Ro a ing wide- angle wind as aced by he lowe eloci y HCN emission is indi- ca ed by he hollow bi-sphe es. Do ed lines a e added o he ends o he hollow bi-cones o indica e hei ex ension u he ou . The ou lowing OH megamase emission is exci ed owa d he egions indica ed by do ed o ange ellipses. H2CO megamase emission (FMM) is exci ed in he inne egions o he nuclea disk, indica ed by do ed magen a. We ha e u he mo e d awn he ex ended nuclea disk in semi anspa en g ay-scale, as well as he la ge-scale adio je , ha is di e en ly inclined om he ou low sys em aced by HCN and OH. unde local he modynamic equilib ium (LTE; Des ombes e al. 1977). The ela i e peak abso p ion o he lines ollow he a io expec ed unde LTE. Howe e , di e en line p o iles we e ound among he ansi ions, which was in e p e ed as he esul o OH gas ha is exci ed unde a ying condi ions, comp is- ing he signal (Fals ad e al. 2018). Fu he mo e, Fals ad e al. (2018) ound ha he spa ially and kinema ically esol ed emis- sion om he 4.751 GHz ansi ion, indica e ha he dominan pa o he emission eme ges om a o a ing s uc u e along he majo axis, while hey ound en a i e e idence o a ea- u e a ∼200 km s−1 o he no hwes o he con inuum peak. McB ide e al. (2013) obse ed he sa elli e ansi ions associ- a ed wi h he 1.67 GHz OHM a 1.612 and 1.712 GHz using he A ecibo elescope. F om he conjuga e line p o iles o he OHM sa elli e lines, hey concluded ha wo sepa a e in e sion mech- anisms exis in Zw049.057. Ea lie , we showed ha he OHM appea s in an ou low- ing s uc u e along he galac ic mino axis. The OH ou low appea s o en elop a collima ed and dense ou low aced by high- eloci y HCN emission. While OH is obse ed owa d he nuclea disk in i s 6 cm and a -IR lines (Fals ad e al. 2015, 2018), we de ec i he e nei he as a mase no in abso p ion in he 1.667 and 1.665 GHz ansi ions. This, while H2CO is obse ed as a megamase in associa ion wi h he nuclea disk. The combina ion o hese obse a ions con i ms ea lie con- jec u es ha dis inc exci a ion mechanisms o egions exis o he OH emission owa d Zw049.057 (McB ide e al. 2013; Fals ad e al. 2018). The p esence and absence o OHM and H2CO mase emis- sion allows us o cons ain he exci a ion condi ions in he ou low and nuclea egion o Zw049.057. I is well es ab- lished ha OH megamase s appea in associa ion wi h FIR adia ion a ound 53 µm abso bed h ough he OH 2Π1 2−2Π3 2 J=3 2−3 2 ansi ions, which causes popula ion in e sion in he ansi ions a ound 1.67 GHz h ough adia i e pump- ing (Locke & Eli zu 2008). Popula ion in e sion is achie ed in u bulen clumps (∆ ∼20 kms−1) o sizes .1 pc, num- be densi ies .105cm−3and speci ic OH column densi ies o he o de 1016 cm−2km−1s. Fo such clumps, mase op i- cal dep hs τ1.667 GHz ∼ −1 a e expec ed (Locke & Eli zu 2008). A b igh (non he mal) backg ound adia ion ield a ound 18 cm wa eleng hs is equi ed o OH megamase s o be appa - en , while mul iple mase clumps along he line-o -sigh may boos he ampli ica ion o his backg ound adia ion signi i- can ly (Pa a e al. 2005). De ailed modeling o he exci a ion o H2CO mase s inds ha he 4.8 GHz H2CO mase is exci ed owa d dense egions &105cm−3, whe e he mase pumping is collisional ( an de Wal & M ulwane 2022). Mase pumping can ope a e in en i onmen s wi h a p ominen FIR adia ion ield, p o ided he gas empe a u e exceeds he adia ion em- pe a u e ( an de Wal & M ulwane 2022). A a he es ic i e cons ain ha an de Wal & M ulwane (2022) pu o he ope - a ion o H2CO mase s, is ha i equi es H2CO o be p esen in high abundance (xH2CO ∼10−5). Such H2CO abundances a e 3 o 4 o de s o magni ude highe han wha is ypically ound owa d Galac ic s a o ming egions, ho co es o da k clouds (see, e.g., Mangum & Woo en 1993;Tang e al. 2018; Ki sano a e al. 2021). We no e, ha he abundance cons ain was o mula ed o H2CO mase s exci ed owa d high-mass s a - o ming egions. Fo H2CO megamase s, eloci y-cohe ence leng h scales, `, can be wo o de s o magni ude highe , while line-wid hs, ∆ , a e one o de o magni ude highe . Thus, ak- ing in o conside a ion ha (la ge- eloci y g adien ) adia i e ans e p oblems depend p ima ily on he speci ic column den- si y, xH2COnH2`/∆ , he abundance equi emen s a e elaxed by abou an o de o magni ude. S ill, aking his in o conside a ion, H2CO abundance equi emen s seem oo high, and we sugges dedica ed modeling o H2CO megamase sou ces is equi ed o add ess his issue. We sugges ha he absence o OH emission o abso p- ion a ound 1.67 GHz in he nuclea disk is he consequence o he high densi ies in hese egions, ha e ec i ely supp ess he mase mechanism. Ins ead, because o he ou low expansion, OH clumps in he ou low s uc u e a e mo e enuous, allowing hus o e icien mase pumping. In addi ion, o he OHM o ope a e, one equi es e icien FIR pumping. The FIR adia ion in he OH ou low may ei he eme ge om he CON egion, o om he collima ed dense pa o he ou low ha is aced by high- eloci y HCN emission, and which he OH ou low en elops. While he CON egion sub ends a la ge solid angle as seen om he OH ou low, abso p ion may diminish i s p ominence. On he o he hand, conside ing he li e ime (∼105yea s) o he col- lima ed ou low, we equi e a mechanism such as s a o ma ion in his egion o hea up he dus phase, o accoun o he eme - gence o FIR adia ion he e om. 4.5.2. The class o OH megamase s and CONs A syn hesis o he OHM su eys by Baan (1989) and Da ling & Gio anelli (2002) and he hos galaxy IR, CO and HCN luminosi ies, indica e an associa ion be ween OHM and high molecula gas densi ies and ac ions, as well as an unusual A163, page 8 o 11 Lankhaa , B., e al.: A&A, 689, A163 (2024) IR-CO luminosi y ela ion (Da ling 2007). On he basis o his, i is sugges ed ha OHM a e associa ed wi h a com- pac and in ense mode o s a o ma ion ha is likely ig- ge ed by idal densi y enhancemen s due o me ge e en s (Da ling 2007). This pic u e is consis en wi h modeling e o s (Pa a e al. 2005;Locke & Eli zu 2008), and a e no in en- sion wi h p e ious high esolu ion imaging o he OHM using VLBI ins umen s (Lonsdale e al. 1998;Pihls öm e al. 2001; Richa ds e al. 2005), ha we e pe o med on, p ima ily, he mo e luminous OHM. Howe e , ou high- esolu ion obse a- ions o he OHM emission ha show he associa ion wi h an ou - lowing s uc u e owa d he LIRG Zw049.057, equi e a mo e sub le pic u e o he class o OHM. We poin ed ou ea lie ha Zw049.057 is a CON, a sub- class o (U)LIRGs ha hos excep ionally dense nuclea egions and a e associa ed wi h bo h in low and ou low mo ions. While only a small ac ion (.10%) o LIRGs, and up o a hi d o ULIRG galaxies hos OHM (Da ling & Gio anelli 2002), almos all LIRG and ULIRG CON galaxies ha ha e been sea ched o OHM emission, indeed hos OHM. A i s , his is no su p ising, as OHM a e associa ed wi h high densi y gas (Da ling 2007), and show p ominen abso p ion in OH a ound 53 µm, which is a equisi e o OH mase pumping (González-Al onso e al. 2012,2015). Ye , o he known H2CO megamase s, 5/6 a e hos ed by CONs, o which 1 o hem is a ULIRGs (A p 220) and he 4 o he s a e LIRGs (IC 860, UGC 5101, IRAS 17578–0014, Zw049.057), whe e each o hem is addi ionally associa ed wi h OH mase emission. The associa ion o he OHM wi h H2CO megamase appea s p oblema ic, as only e y limi ed condi ions allow o he simul aneous exci a ion o bo h H2CO and OH megamase s. Ou high- esolu ion in e e ome ic obse a ions show ha he issue o he appa en associa ion be ween OHM and H2CO megamase emission can be esol ed, as hey eme ge om di e en egions; ou low (OHM) and nuclea disk (H2CO megamase ) s uc u es. We specula e ha a simila a angemen may be p esen o he o he LIRGs ha hos OH and H2CO megamase . 4.6. OH megamase s a high edshi Un a ge ed HI su eys di ec ed o dis an objec s, a e o en sensi i e o OH mase lines, oo (B iggs 1998). While OHM de ec ions in HI su eys may be seen as con amina ions, using spec oscopic edshi s i a ailable, o mo e elabo a e me h- ods using he hos galaxy con inuum p ope ies, OHM galaxies may be posi i ely iden i ied and isola ed om hese HI su eys (Robe s e al. 2021). Indeed, ongoing HI su eys a e apidly adding o he known sample o OHM galaxies (Bly h e al. 2016;Hess e al. 2021;Glowacki e al. 2022;Ja is e al. 2024), and will likely iple he numbe o known OHM galaxies (Robe s e al. 2021). Fu he mo e, planned HI su eys using he nex -gene a ion o adio elescopes, ha will sample galaxies a e en highe edshi , will likely inc ease he numbe o known OHM galaxies by some o de s o magni ude (Robe s e al. 2021). Wi h his expec ed su ge in OHM de ec ions in dis an galaxies, i is na u al o discuss he implica ions o he cu en s udy. F om he in e e ome ic mapping o he OHM owa d Zw049.057, ou main inding is i s associa ion wi h an ou - low, and he supp ession o emission owa d he nuclea disk. The ou low aced by OHM is expanding a a low eloci y (∼100 km/s), making i di icul o de ec spec oscopically. This is in con as o o he s udies ha ha e associa ed OHM wi h ou - lows (Baan e al. 1989;Gowa dhan e al. 2018;Glowacki e al. 2022), ha ound OHM emission a la ge (200−1000 km/s) o - se s om he sys emic eloci y. The luminosi y o he OHM o Zw049.057 (10.1±2.0L) is on he lowe end o he ange o OHM luminosi ies. This ea u e can be asc ibed o (i) Zw049.057 being a LIRG, wi h a na u ally weake adio- con inuum ha is o be ampli ied by OHM, (ii) he sligh o se o he OHM om he con inuum maximum, and (iii) he ela- i ely small egion ha is conduci e o popula ion in e sion. In pa icula , poin s (ii) and (iii) a e a di ec consequence o OHM acing an e ol ed ou lowing s uc u e. A use ul ea u e o he un a ge ed HI su eys, is hei b oad- band scanning. Thus, i is likely ha o an OHM galaxy, no only he main OHM lines a 1.67 GHz will be de ec ed, bu also sa elli e ansi ions a 1612 and 1720 MHz. A comp e- hensi e analysis o he di e en ansi ions can e eal p op- e ies o he (pumping) condi ions owa d he OHM galaxy (Baan e al. 1987). Such an analysis has al eady been p oduc- i ely applied by Hess e al. (2021) o an OHM ound in he HI su ey AWES (Ape i Wide-a ea Ex agalac ic imaging Su - ey). Fo Zw049.057, analysis o he OHM lines and hei sa el- li es, e ealed he p esence o di e en pumping condi ions o he OHM; a ea u e which we can con i m h ough ou in e e - ome ic obse a ions. Mul iline analysis o he OHM lines and hei sa elli es will e eal impo an in o ma ion on he pump- ing condi ions, bu o o mula e igo ous ela ions ha e eal he OHM associa ion wi h an ou low, mo e in e e ome ic s udies such as his one a e necessa y. To di ec addi ional in e e ome - ic s udies, we ha e poin ed o H2CO megamase emission as a ma ke o OHM galaxies wi h OHM emission acing ou low s uc u es, simila o Zw049.057. 5. Conclusions We p esen high-angula esolu ion in e e ome ic obse a ions o he kinema ics o he nuclea egion o Zw049.057. Using e-MERLIN, we obse ed he H2CO and OH megamase s, and using ALMA, we obse ed HCN 3 →2 emission. The H2CO megamase aces he nuclea disk, while he OH megamase aces a slow and wide-angle ou low. The slow and wide-angle OHM ou low in u n appea s o en elop a as and collima ed ou low ha is aced by high- eloci y HCN emission. Momen um es ima es indica e ha he OH megamase ou - low may be adia i ely launched, while he as and collima ed molecula ou low aced by HCN equi es an addi ional momen- um boos . Such a momen um boos may be achie ed i he ou - low is en ained by an ene gy-conse ing AGN wind, o h ough a magne o-hyd odynamical launching mechanism. F om he low eloci y o he OHM ou low and an analysis o he d i ing o ces, we conclude ha he wide-angle OHM will likely no each escape eloci y, and ins ead e ol e as a oun ain low. We obse ed he H2CO and OH megamase o be associ- a ed wi h di e en physical s uc u es. The exci a ion o OH and H2CO megamase s equi e di e en condi ions, ha a e almos mu ually exclusi e, ye o he known H2CO megamase s, all o hem ha e been ound owa d OH megamase galaxies. Addi- ionally, i e o he six known H2CO megamase s a e ound owa d CONs. Since he p ime cha ac e is ic o CONs is dense nuclea gas, and hey a e commonly associa ed ou low sys ems, we specula e ha a simila a angemen can be expec ed o he OH-H2CO (hyd oxyl- o maldehyde) megamase galaxies. Ou high-angula esolu ion in e e ome ic obse a ions ha e e ealed mul iple phases o ou lowing gas emana ing om he inne (.10 pc ), and obscu ed (NH2∼1025 cm−2), nuclea egions o Zw049.057. While he ul ima e d i ing mechanisms o he ou lowing gas phases emain ambiguous, i is clea ha A163, page 9 o 11