Redalyc.MAGNETIC FIELDS and STAR FORMATION in SPIRAL

Revista Mexicana de Astronomía y Astrofísica ISSN: 0185-1101 [email protected] Instituto de Astronomía México

Krause, M. MAGNETIC FIELDS AND STAR FORMATION IN SPIRAL GALAXIES Revista Mexicana de Astronomía y Astrofísica, vol. 36, 2009, pp. 25-29 Instituto de Astronomía Distrito Federal, México

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How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative © 2009: Instituto de Astronomía, UNAM - Magnetic Fields in the Universe II: From Laboratory and Stars to the Primordial Universe Ed. A. Esquivel, J. Franco, G. García-Segura, E. M. de Gouveia Dal Pino, A. Lazarian, S. Lizano, & A. Raga oeod equipartici´ de modelo t´ fracciones formaci´ de comparaci´ una hace es ieet F.Et mlc u oa sa aaispoue nvet gal´ viento un producen galaxias estas el independientemente todas ambos, GHz), que para 4.75 implica vertical a escala Esto kpc la SFR. (0.3/1.8 radio– diferente iguales el aproximadamente su en son de aspecto ancho/halo, diferente disco su el de y delgado pesar disco –a galaxias cuatro en que Encontramos ehc n rese˜ una hace Se amgiu patr´ y magnitud la rhg F.Aotn neupriinmdl ecnld httennhra ai msinadthe and emission radio nonthermal the that conclude normal we with model, found those We equipartition than field (SFR). fractions an within magnetic rates synchrotron Adopting compared fractions/smaller formation SFR. thermal and star higher high and summarized have or inclinations, field are SFR types, low magnetic galaxies morphological with spiral the different galaxies edge-on that about of and galaxies observations of face-on polarization sample for and our pattern continuum large-scale radio and from strength results observational main The escalas la que mientras SFR, la con eflj elsrysc´ rayos los de flujo de bonn.mpg.de). eMxA(ei eConferencias) de (Serie RevMexAA ag-cl antcfil ofiuain aallt h ipaeadXsae ute wyfo h disk the also the that from conclude away we similar Hence further a is show disk. X-shaped (CR) also the and rays sample in cosmic our midplane SFR the in and the of galaxies type field velocity to The Hubble bulk SFR. of parallel disk. the different independent galactic configuration, both, which their plane, the in of for field within independently wind, heights magnetic strength GHz), galactic scale field large-scale 4.75 a vertical total at host the the kpc galaxies by appearance– (0.3/1.8 these determined equal radio all about that different are implies their disk/halo, This –despite thick that and thin galaxies the four in found We SFR. on depend e iod ubeyl F ne ic.Cnlio as´ Concluimos disco. el en SFR la gal´ y medio Hubble plano de tambi´ del tipo muestran del cerca muestra paralela nuestra similar, en escalas galaxias Las disco. e H¨ dem e Words: Key antcfil.Telnal oaie nest re- intensity polarized linearly total The the of field. strength magnetic the the of gives intensity emission total The synchrotron study to galaxies. way in fields best magnetic the are regime cm-wavelength the 1 ai bevtoso h otnu msinin emission continuum the of observations Radio a-lnkIsiuefrRdosrnme Auf Radioastronomie, for Max-Planck-Institute ANTCFED N TRFRAINI PRLGALAXIES SPIRAL IN FORMATION STAR AND FIELDS MAGNETIC pattern suimstambi´ Estudiamos eas tde h antcfil tutr n iktikessi ihyicie eg-n galaxies. (edge-on) inclined highly in thicknesses disk and structure field magnetic the studied also We gl6,511Bn,Gray(mkrause@mpifr- Germany Bonn, 53121 69, ugel odpned aSFR. la de depende no netlr(Fsprsssga ningl´ en siglas sus por (SFRs estelar on ria/eoe rcinssincrotr´ fracciones ermicas/menores aais ao aais niiul(G 9,NC43)—glxe:mgei ed galaxies: — fields magnetic galaxies: — 4631) NGC 891, (NGC individual galaxies: — halos galaxies: prl—polarization — spiral osntdpn nteaon fSFR. of amount the on depend not does teghgo olnal ihSR hl the while SFR, with nonlinearly grow strength .INTRODUCTION 1. ad o rniae eutdsd bevcoe eradio-cont´ de observaciones de resultados principales los de na naga saad o apsmagn´ campos los de escala gran a on ncnuametad aaiscndfrne io morfol´ tipos diferentes con galaxias de muestra una con on sio eecetadtriaaprl antddlcmomagn´ campo del magnitud la por determinada encuentra se osmicos n ocumsqel emisi´ la que concluimos on, nl srcuayacod o icse aaiscnatsiciains(ecanto). (de inclinaciones altas con galaxias en discos los de ancho y estructura la en intensidad , 36 e ap magn´ campo del 52 (2009) 25–29 , nqeaula o Fsnrae la.Aotnoun Adoptando altas. o normales SFRs con aquellas que on ABSTRACT s.Ecnrmsqeglxa o aaSRtee mayores tienen SFR baja con galaxias que Encontramos es). RESUMEN nn t´ no on .Krause M. cioycnfrad eo e´ de lejos X de forma con y actico etico nuaconfiguraci´ una en ıquetambi´ riayel y ermica tcse aaistnod at ood aa se y cara, de como canto de tanto galaxias en eticos eemnn h oainmaueR bigpro- (being RM by measure to wavelengths portional rotation more– the better determining –or ob- us. with two to possible at origin is servations radiation’s rotation Faraday the for from Correction way their depolariza- polariza- and on observed rotation tion the Faraday to However, suffer perpendicular vectors sight). tion (i.e. of plane resolved line sky the the the of in structure field the regular and strength the veals 1 regular regular npatr´ en ap magn´ campo oprc eedrd ´ de depender parece no antcfield magnetic n e ndlcmomagn´ campo del on B ndlcmomagn´ campo del on dl ). noypolarizaci´ y ınuo tc total etico gcs nlncoe,ytasas y inclinaciones, ogicos, cio ne ull velocidad la cual el en actico, B strength se independientemente este, stechrn magnetic coherent the is tc oa etodel dentro total etico large-scale rcnlinealmente crecen esta. osntse to seem not does tc grandes a etico tc a etico naec de acerca on magnetic grandes total 25 © 2009: Instituto de Astronomía, UNAM - Magnetic Fields in the Universe II: From Laboratory and Stars to the Primordial Universe Ed. A. Esquivel, J. Franco, G. García-Segura, E. M. de Gouveia Dal Pino, A. Lazarian, S. Lizano, & A. Raga eeal prlptenwt ic-nlsfo 10 from pitch-angles with pattern spiral a generally 1996). Hoernes & iei C4 Kas ta.18;Kas 93 rso- or 1993) Krause 1989; intensity called al. et polarized (Krause of IC342 filaments in like long large- form the filled cases field is other scale in region fields, interarmed regular with the smoothly spi- density-wave Sometimes, the of arm. edge inner ral the at spi- or optical arms, the the ral between in whereas strongest arms, are fields spiral regular optical the along strongest 2008). al. et (Fletcher M51 and 2008) ausu o10 to up few values a 1–5 of typically resolution are spiral spatial 100pc) in a fields with magnetic (observed regular galaxies the of fields. rate magnetic strength formation total The star stronger generally high have a to tend with galaxies or galaxies h prlam fu o20 to values up of higher arms locally 9 spiral average reach the however, on is can, galaxies spiral (1995) It 74 Niklas of by sample a observed for strength field netic ewe h nriso h antcfil n the and field so-called tion magnetic (the the particles of relativistic equipartition ra- a energies of nonthermal assumption the in the between the KRAUSE strength from under field emission estimated dio magnetic be can total galaxy The com- strength). turbulent and equal ponents. regular of (of for consist zero fields fields but Magnetic sight, antiparallel of and large line is the parallel RM along the fields whereas sky, parallel the for of plane dis- the direc- in not field tions does antiparallel it and only parallel i.e. between is orientation, tinguish intensity field 3- the polarized a to the sensitive deduce that to field. however, principle magnetic Note, large-scale in the of us picture enable dimensional the sight, to gives of perpendicular sign line and its Both parallel and component. components, field sight, field magnetic of this of line direction the the to parallel field 26 n oeigawd ag nSRwr bevdwith observed were SFR in range wide a covering and irregular and flocculent fields in galaxies. magnetic observed spiral been Further, even have arms. spiral optical o40 to .OSRAINLRSLSO MAGNETIC OF RESULTS OBSERVATIONAL 2. h antclnso h ag-cl edform field large-scale the of lines magnetic The h ubln antcfil stypically is field magnetic turbulent The h eneupriinvlefrtettlmag- total the for value equipartition mean The eea deo aaiso ieetHbl type Hubble different of galaxies edge-on Several sdsrbdi ek&Kas (2005). Krause & Beck in described as ) ◦ antcsia arms spiral magnetic hc r iia otepthage fthe of angles pitch the to similar are which 2.2 2.1 prlGlxe enedge-on seen Galaxies Spiral . prlGlxe enface-on seen Galaxies Spiral . − 15 μ seg nNC64 (Beck 6946 NGC in e.g. as G FIELDS μ ,admyrahlocally reach may and G, μ iei G 96(Beck 6946 NGC in like .Srnl interacting Strongly G. nryequiparti- energy ± within 3 μ G. ◦ 9 oehrwt h ai otnu msinat emission continuum NGC radio galaxy the the λ edge-on show with the we together of example, 891 vectors an As field magnetic plane. the X-shaped from looks 2008b). away field al. magnetic et large-scale Heesen magnetic the 2006; Hence, al. the 2004; et with (Krause Krause disk radius 2005; increasing with Soida the and components disk from the vertical from Away distance also has 1996). field mean-field al. a et of by face- amplification action field of the magnetic observations their from and of galaxies expected exception on only as the 4631) (with disk NGC the of midplane the f¨ vrae na pia mg fteglx nFig- in galaxy the of 1. image ure optical an on overlayed mainly is magnetic the structure that field show observations polar- linear These and ization. continuum radio in sensitivity high 84 of spi- resolution a edge-on with the telescope Effelsberg of at m 891 emission NGC continuum galaxy Radio ral 1. Fig. cp/c19 CFHT/Coelum. scope/(c)1999 on.Terdompi vrae na pia im- Tele- optical Canada-France-Hawaii an the on from overlayed 891 is NGC map of radio age MPIfR the The vectors (Copyright: the orientation Bonn). intensities, field total magnetic the intrinsic give contours The rRdosrnme(Pf)i Bonn. in (MPIfR) Radioastronomie ur 3 . 2 c md ihteEeseg10mtelescope m 100 Effelsberg the with (made 6cm h fflbr 0 soeae yMax-Planck-Institut by operated is m 100 Effelsberg The λ 3 . c 83 H)wt h 100 the with GHz) (8.35 6cm aallt h disk the to parallel α -yao(..Beck (e.g. Ω-dynamo HPBW along 2 . © 2009: Instituto de Astronomía, UNAM - Magnetic Fields in the Universe II: From Laboratory and Stars to the Primordial Universe Ed. A. Esquivel, J. Franco, G. García-Segura, E. M. de Gouveia Dal Pino, A. Lazarian, S. Lizano, & A. Raga the a rcinadwa oa n eua magnetic regular ther- and high total unusually (Chy˙ weak fields an re- and have SFR) fraction all low mal a they with that (all radio-weak vealed 5907 the NGC and galaxy surface-brightness edge-on low with ies AND STRENGTH FIELD MAGNETIC TOTAL 3. 5775 NGC coun- and three statistics. 4254, The the NGC balances 1998). 891, Beck explained NGC & be terexamples (Krause not were now could 6949) to which NGC up and directed, to up inwards 253, determined all NGC be IC342, could (M31, which ASS for now the galaxies of four direction other di- the outwards The of fields. examples first ASS the rected are these prep.) in G 24(Chy˙ 4254 NGC S edi G 9 is 891 NGC in field the galax- that face-on ASS infer in observed can we as arms ies) opical the to allel field spiral positive magnetic optical a and trailing nega- (and galaxy Assuming arms also the one. of southern are the part 891 in northern NGC the in in tive velocities rotation the i fnnhra-otemleiso nrae with ∝ increases emission nonthermal-to-thermal of tio deo aais(G 5,NC81 G 3628, NGC at 891, NGC emission 253, (NGC power galaxies total edge-on the of eain(ils&Bc 97,acrigt which to increases cor- according emission radio-FIR 1997), fits nonthermal the Beck the findings & for Our (Niklas model inten- SFR. relation equipartition thermal the the the to to that proportional known higher is already with sity fraction is lower galaxies It a than SFR. have emission measured galaxies synchrotron values these of lowest Hence, the corre- far. to radio-FIR so it total the extending follow lation, still objects these 91 Garc´ 1991; our mta antcfil nNC81sest ean az- be the to axis, seems 891 major NGC above the even in signs along field equal magnetic disk have imuthal the RMs below the the As and within field disk. toroidal galaxy. southern galactic large-scale the the of a part indicates in northern This values the in positive negative axis and with major part the galaxy along the smoothly of vary (1991) Allen & sgnrtdb mean-field a by generated as SFR bevtoso apeo he aetp galax- late-type three of sample a of Observations eas eemndteepnnilsaeheights scale exponential the determined also We rmteH-adC-ieosrain (Rupen observations CO-line and HI- the From between determined (RM) measures rotation The total λ xsmercsia ed(S)(rue1990) (Krause (ASS) field spiral axisymmetric 3 . c-a n the and 6cm-map ≈ 0 antcfil tegha ela h ra- the as well as strength field magnetic . 4 y20;Dmee l 00.However, 2000). al. et Dumke 2007; zy aBrlo&Gu´ & ıa-Burillo . y20)adNC57 Siae al. et (Soida 5775 NGC and 2008) zy TRFORMATION STAR direction outwards orientation λ ln19)w nwthat know we 1995) elin 6 α . c-a fSukumar of 2cm-map Ω − yao(cf. dynamo ftelarge-scale the of λ oehrwith Together . ∝ ANTCFED NGLXE 27 GALAXIES IN FIELDS MAGNETIC mfrfour for cm 6 rmrl par- primarily SFR ≈ 1 . 4 § and 4). i.2 ai otnu msino h deo spi- edge-on the at of 4565 emission NGC continuum galaxy Radio ral 2. Fig. rmosrain ihteVAadte10mEffelsberg m 20 100 with the telescope and VLA the with observations from ftewaethls G 55 ihasalSFR. one small as a well with as 4565, SFR NGC high halos, weakest very so the a observed of with halo that 253, stress brightest NGC We the far, 2008). includes (Dumke al. sample 1.8kpc) et our Heesen and 1998; (300pc Krause sample & this in similar the emission, radio the heights of extents and 4565 Ef- tensities NGC m of 100 map The the wavelength. and this (VLA at data felsberg) single-dish and eter ei edoinain h ai a soelydo an on overlayed is mag- map intrinsic radio the The vectors orientation. the field netic intensities, total the give pia mg fNC46 Cprgt Pf Bonn). MPIfR (Copyright: 4565 NGC of image optical egt at heights such of wind. existence galactic the a Breitschw- for correlations by deduced support above observational the e.g. and give 1991), proposed al. (as et wind erdt galactic (CR) rays a de- cosmic best in of be transport convective can a speed as scale- bulk scribed ray power cosmic least The total at km/s. of speed the 280 lifetimes) synchrotron bulk of CRE the ray ratio and height cosmic the a as with mainly (determined is direction transport vertical ray cosmic in the electron disk. that underlying ray implies the cosmic This in the emis- lifetimes of synchrotron radio functions (CRE) the linear of are scaleheights sion local the that found in- different their of spite In 2. Figure in shown is interferom- combined have we which for 4565) NGC h atta eosresmlraeae scale- averaged similar observe we that fact The (2008a) al. et Heesen 253, NGC of case the In fteti ikadtetikds/aoare disk/halo thick the and disk thin the of λ mfrtefu aaismentioned galaxies four the for cm 6 HPBW λ 6 Dme19) h contours The 1997). (Dumke . c 48 H) combined GHz), (4.85 2cm scale © 2009: Instituto de Astronomía, UNAM - Magnetic Fields in the Universe II: From Laboratory and Stars to the Primordial Universe Ed. A. Esquivel, J. Franco, G. García-Segura, E. M. de Gouveia Dal Pino, A. Lazarian, S. Lizano, & A. Raga 8KRAUSE ( the that lifetimes assumption synchrotron the with –together imply above 28 npriua hs for those particular in polar- ( of lower degree is the ization effects) (inde- inclination that found of and pendently galaxies spiral nearby 41 in ties 2 = degree P global is the 5907 2008), NGC in al. galaxy polarization et total of Stil the over in Q-maps described and (as U-, 3 I-, = Stokes P the galaxies, both in equal hcnse–ta h Rbl pe o galactic (or B speed to proportional bulk is CR velocity) wind the that thicknesses– lto f84 at of polarization olution of Surpris- degree the formation. 1) normal star ingly, a Figure strong intensities, (see and polarized fraction 891 thermal and NGC total low hand, strong a other has and the po- fraction On and thermal SFR. total high weak a a intensity, has larized 5907 in mag- NGC the discussed galaxy of edge-on As uniformity of field. degree the netic of measure intensity) total a and is intensity polarized determined of ratio (as and the P by strength polarization of field degree magnetic observed the regular the estimate to otoa oSFR to portional nNC81i sol 1 = P only is it 891 NGC in ao u apeicue prlglxe fvery 0 of from ranging galaxies SFR, spiral and includes type Hubble sample different the Our in field magnetic poloidal halo. X-shaped disk-parallel the a with inner mainly together the field 4631) (in exception NGC one of with part them of all in found SFR. local the regular and and the anticor- strength between SFR field correlation an with any detect found regularity not field he could field magnetic SFR, he total of local While the relation the between and 4254. correlation strength strong NGC a galaxy, found one SFR and within regularity locally field magnetic between relation field magnetic the reduce to regularity. seems formation stronger star that conclude From we however, observations, direction. vertical our in the velocities as for force remnants dynamo driving supernova with mean-field and those the formation are star course, needs galaxies Of brightest SFR. The highest the 2008). al. et SFR .RGLRMGEI IL N STAR AND FIELD MAGNETIC REGULAR 4. iial,w nertdteplrzto proper- polarization the integrated we Similarly, h oaie nest nsia aaisallows galaxies spiral in intensity polarized The norsml f1 bevdeg-nglxe we galaxies edge-on observed 11 of sample our In Chy˙ kpc-scales, On ≤ 7 h ikprle antcfil ln the along field magnetic disk-parallel The 27. HPBW < 0 . 8 % o oelmnu galaxies, luminous more for 4%) . FORMATION L y(08 nlzdtecor- the analyzed (2008) zy ∝ hl oe emwdh is width) beam power (half 4 . 8 B > − . 6%. § . 2 % hnw average we When 2%. 2 eemn h disk the determine ) h o brightness low the 3 × 10 2 n ec pro- hence and , λ 21 ma res- a at cm 6 . WHz % whereas 2%, − 1 . (Stil 5 ≤ ietettlitniis h etr h nrni mag- intrinsic the vectors the intensities, total the give i.3 ai otnu msino h deo spiral edge-on the at of 4631 emission NGC continuum galaxy Radio 3. Fig. nFgr .Teinner visible The as disk, the 3. of Figure midplane the in in also at field only scale disk the along has radii field which dynamo however, magnetic 4631, The disk-parallel NGC a differential disk. strong 1988). the of in regions rotation al. in effectively et most Ruzmaikin acts (ASS) spiral (e.g. axismmetric the field is by pattern field generated excited be to thought mean-field generally a face-on is of in It observed projection as galaxies. disk edge-on the expected within spiral-field the the is disk galactic 84 with telescope Effelsberg pia mg fNC43 ae ihteMsiMoun- Misti Bonn). the MPIfR with (Copyright: taken an Observatory 4631 on tain overlayed NGC is of map image radio optical The orientation. field netic in the rises hence curve 1994), rotation Wielebinski mean-field & the (Golla where rigidly 4631 nearly NGC of region edcngrtosa h bevdoe.Sc a Such ones. observed the as configurations field a including halo wind spherical a by surrounded mean-field Model the strengths. of field com- calculations disk be large-scale to the seems to there parable strengths field the edge-on the as in that galaxies structures cannot alone X-shaped means observed mode This the dynamo explain ASS the field. of weaker part disk 10 poloidal about toroidal of the factor poloidal a than however, quadrupolar is, which a field, with accompanied theory– not may hence and field. 4631 large-scale NGC disk-parallel a of amplify part inner this in § h vnASmgei ikfil a discussed (as field disk magnetic ASS even The ≥ .)i acrigt h enfil dynamo mean-field the to –according is 2.2) Badnuge l 93 iuae similar simulated 1993) al. et (Brandenburg kc hw o mle ai etcllarge- vertical a radii smaller for shows 5kpc, α α Ω Ω − − yaomyntwr effectively work not may dynamo yaofrwihtems easily most the which for dynamo λ 3 . c 83 H)wt h 0 m 100 the with GHz) (8.35 6cm ≈ p (140 kpc 5 HPBW α -yaofradisk a for Ω-dynamo h otusin contours The . sjs the just is ) galactic © 2009: Instituto de Astronomía, UNAM - Magnetic Fields in the Universe II: From Laboratory and Stars to the Primordial Universe Ed. A. Esquivel, J. Franco, G. García-Segura, E. M. de Gouveia Dal Pino, A. Lazarian, S. Lizano, & A. Raga lyddcdeg sdsrbdin described as observation- been e.g. deduced already ally has (which wind galactic httettlmgei edsrnt euae the regulates strength velocities. field wind imly galactic magnetic galaxies total and these the heights in that scale configurations similar field The magnetic emission. heights field radio scale global the global the of the change influences cannot in nor it field configuration halo– magnetic total and the disk increases the disk the in SFR (D. velocities comm.). gas priv. vertical Elstner, of et in- self-generation simulations Sur a dynamo dicate numerical (e.g. Recent action 2007). dynamo al. of problem helicity the Chy˙ uk,M,&Kas,M 98 et oe hs,506, Phys., Notes Lect. 1998, M. Bonn Krause, of & University M., thesis, Dumke, PhD 1997, M. Dumke, Chy˙ rished,D,MKni,J . V¨ & F., J. 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