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Virgo Cluster Spiral Galaxies and Their Mach Cones

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Virgo Cluster Spiral Galaxies and Their Mach Cones Virgo Cluster spiral galaxies and their Mach cones M. We˙zgowiec1, B. Vollmer2, M. Ehle3, R.-J. ettmar1, D. J. Bomans1, K.". Ch#˙z#4, M. $rbani&4, M. 'oida4 1 (stronomisches )nstitut der Ruhr-Uni*ersit+at Bochum, Bochum, German# 2 C ', -%ser*atoire astronomi.ue de Stras%ourg, Stras%ourg, /rance 3 E'(C, 0MM-1ewton 'cience Operations Centre, Villanue*a de la Ca2nada, Madrid, 'pain 4 Obserwatorium (stronomiczne $niwers#tetu Jagiello3ns&iego, !ra&3ow, 4oland Over the years many observations have 1GC 89EA (Fig. 2) shown the environmental influence on Virgo •@ne o% the lar#est an m ost *i e+cient #alaxies in the Vir#o cl"ster ((olanes et al. 2001, A!C, 549, 97) Cluster spiral galaxies: •A #iant hot #as iB"se h alo o% 20� ×20 � (100× 100 1!c) •Radially truncated gas disks (Cayatte et • Dar#e ra io lobes (8hy<zy et al. 2005, A&A, 447, 455). al. 19 !" #$" 1!!" %!&' Chung et al. (!! " •,he hot !hase at∼0.5 1eV (Fi#. 5 ri#ht) has a !ress"re 2 times #$" 1) " (*1%+ lo.er that that o% the cosmic rays an ma#netic +el s • "he radio lobes and the hot gas halo most li&el# ori- •,ong -i tails (Chung et al. (! !*" #.#" gin 5rom galactic superwind dri*en %# cosmic ra#s %/ " 11/+ • "he magnetic field strength estimated 5rom the Mach cone angle is∼3-5µ, 5or an intracluste r medium • Asymmetric polarized radio ridges mark1 densit# ofn∼10 −4 cm−3 ing gas compressions and shear motions NGC 4388 H I on XMM-Newton MOS1+MOS2+pn 0.2 - 1 keV (We3zgowiec et al. (!!*" #.#" &*1" )' Vollmer et al. (!!*" #.#" &%&" ,)*+ Cont peak flux = 7.5213E+01 10^19 cm 13 00 "he model. Recently, Vollmer (2009, A&A, 502, 427) es- tablished a mo el-based ram !ress"re stri!!in# time se$"ence o% Vir#o s!iral #alaxies' • (na!shots o% three- imensional mo els incl" in# ram !ress"re 12 55 are com!ared to the obser)ed *i #as istrib"tions an )elocity Fig. =7 An R7> ima#e o% 478 4559 constr"cte %rom -(( o!tical +el s > ban ima#e (green), 0-ray emission (0.2-1 1eV6 bl"e), an 1.4 7*= ) • ,he 3- )elocity )ector an the timestep are matche .ith the total ra io emission (red). ,he lo.er c"t %or both 0-ray an ra io obser)e !ro/ected !osition an ra ial )elocity o% the #alaxy emission is 3σ an the resol"tion is 1?. @)erlai is the 3ach cone #eometry +ttin# the 0-ray lar#e-scale emission. 50 "he Mach cones. Expectations. DECLINATION (J2000 • ,he ram !ress"re stri!!in# heats the #as to 0-ray tem!erat"res • 3ach cones +tte to the 0-ray emission (:i#s. 2 an via bo. shocks, heat con "ction, an the mixin# o% the stri!!ed 3). 45 2(3 into the hot intracl"ster medi"m (e.#. (tevens et al. 1999, •,he irection base on t he ynamical mo el 34RA(, 310, 5536 Roedi#er et al. 2005, 34RA(, 371, 509). • ("!ersonic )elocities o% cl"ster #alaxies ca"ses bo. shoc1s .ith •,he o!enin# an#le +tte by eye associated 3ach cones •,he 3ach cone an#le e! en s on the an#leβ bet.een 40 (ims. the 3- )elocity )ector an the !lane o% the sky • We look 5or signs o5 Mach cones in 0MM-1ewton • 0-ra# observations o5 Virgo Cluster spirals. We suggest that the magnetic field pla#s a role and that the magnetosonic *elocit# is 12 26 45 30 15 00 25 45 rele*ant for the determination of the Mach RIGHT ASCENSION (J2000) NGC 4501 XMM-Newton MOS1+MOS2+pn 0.2 - 1 keV on H alpha num%er • Fig. 87 0-ray emission (0.2-1 1eV) o% 478 4399 to#ether .ith an This allows to estimate the intracluster mag- the *i ma! %rom @osterloo & )an Gorkom (2005). ,he 0-ray ma! 14 31 netic field strength .as c"t at the !osition, .here contrib"tion %rom the 3 95 halo starts to ominate. ,he +rst #reyscale corres!on s to 7 times the rms noise 30 level. 29 NGC4388 tail NGC4569 halo V V 0.2 ) 28 0.4 27 normalized counts/sec/ke normalized counts/sec/ke 0 0.2 0 0.1 26 0 0.05 residuals residuals −0.1 0 0.1 0.5 1 2 0.5 1 channel energy (keV) channel energy (keV) DECLINATION (J2000 25 Fig. 97 (!ectra o% the hot #as tail o% 478 4399 (left) an o% the inner Fig. hot #as halo o% 478 4559 (ri#ht) .ith the +tted mo els. E-o"ble- 24 @7 0-ray emission (0.2-1 1eV) o% 478 4399 (left) an 478 4501 (ri#ht) to#ether .ith the 3ach cone .hose irection is based on the !ea1e E mo el +ts sho. that .e can trace iBerent #as com!onents (i.e. 2(3F283) in the 0-ray emission. 23 ynamical mo el an .hose o!enin# an#le is a /"ste to the 0-ray istrib"tion. ,he #reyscale is cut at 7σ %or 4784399 an 3σ %or 478 4501. 22 1GC 8@>> (Fig. 4) • An im!ressi)e hot #as tail associate .ith the *α !l"me (Goshi a Conclusions7 All extraplanar 0-ray emittin# i 21 et al. 2002, ApC, 557, 119) an the h"#e * tail isco)ered by 12 32 20 15 10 05 00 31 55 50 45 40 @osterloo & )an Gor1om (2005, A&A, 437, D19) RIGHT ASCENSION (J2000) hot gas is %o"n .ithin the Mach cones of the three gala&ies. • ,he s!ectr"m (:i#. 5 le%t) traces the hot 2(3 (∼0.9 1eV) an Fig. 67 0-ray emission (0.2-1 1eV) o% 478 4501 o)erlai onto the the 283 (∼2.3 1eV) �� • *α ima#e %rom Gol mine. ,he ma! resol"tion is 30 . ,he 0-ray 2n 478 4569 it is associated .ith the galactic • ,he thermal !ress"re in the tail is a %e. times lo.er than the conto"rs are 3, 5, 9, 15, 25 times the rms noise level. outAo. obser)e in *α an radio contin""m estimated ram !ress"re (8hy<zyet al. 2006). ,he iff"se 0-ray emis- • "he estimated total gas mass of the tail <∼5×10 9 M�B 1GC 89:6 (Fig. 1) is much lower than the expected stripped gas mass • A stron# com!ression o% the ma#netic +el in the so"th.est sion has a trian#"lar shape. based on the Ci deficienc# <=×6:9M�F Vollmer ? (;e<=#o.iec et al. 2007, Vollmer et al. 2007) • Cuchtmeier 2007, (?(, 462, A@B • i 2n 478 4388 it follo.s the beginnin# of • A shar!ly tr"ncated * is1 at the same !osition i "his could %e due to a strong )'M-)CM mixing, as • A mo erately exten e hot #as halo the * tail isco)ered by Oosterloo & )an well as initial stripping of the outer gas dis&, as pro- posed %# Vollmer ? Cuchtmeier <=::GB •A hot #as tail at∼0.7 1eV Gor1om (2005). • "he o%served characteristics ;ts the ram pressure • 2n 478 4501 it is located op!osite to the stripping model %# Vollmer et al. <=:08, (?(, 483, #cknowledgements ,his .ork .as s"!!orte by -DR Verb"n %orsch"n# 89). si e of the galactic is1 .here the gas is com- EHxtraterrestrische Ihysi1E at R"hr-Jni)ersity >och"m thro"#h #rant 50 • "he 0-ra# emission %eyond the Ci dis& might %e due !resse by ram !ressure (Vollmer et al. 2008) @R 0901 an based on observations obtained .ith 033-4e.ton, an H(A to stripped gas mixed with the intracluster medium science mission .ith instr"ments an contrib"tions irectly %"n e by H(A and/or a galactic wind due to star 5ormation in the an may be stri!!ed gas heated to 0-ray tem- 3ember (tates an 4A(A. prominent northwestern spiral arm. !erat"res. 3ore in' 2011, (?(, 531, 88..
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