dynamical constraints on the dark matter distribution in the milky way

Transcription

1 dynamical constraints on the dark matter distribution in the milky way Miguel Pato (Physik-Department T30d, TU Munich) Oskar Klein Centre for Cosmoparticle Physics / Wenner-Gren Fabio Iocco in collaboration with Gianfranco Bertone APS 4th meeting, Amsterdam, 29 Sep 2014

2 galactic modelling Milky Way edge on dark halo ~8 kpc bulge/bar Sun Galactic Centre 200 kpc gas disk stellar disk bulge tilted bar disk thin+thick gas H 2, HI, HII dark matter??? not to scale! tot = bulge + disk + gas + dm how can we constrain the parameters of a galactic mass model? miguel pato (okc stockholm) () 1

3 galactic modelling tot = bulge + disk + gas + dm {z} {z } dynamics traces total potential rotation curve R 0:1 30 kpc local stars R R 0 8 kpc (Oort's limit) tracers R kpc (radial Jeans) satellites R kpc (virial) \photometry" traces individual baryonic components star counts bulge, disk luminosity bulge, disk gravitational microlensing bulge emission lines gas [Iocco, MP, Bertone & Jetzer, JCAP11(2011)029] [Iocco, MP, Bertone, submitted] miguel pato (okc stockholm) () 2

4 galactic modelling tot = bulge + disk + gas + dm {z} {z } dynamics traces total potential rotation curve R 0:1 30 kpc local stars R R 0 8 kpc (Oort's limit) tracers R kpc (radial Jeans) satellites R kpc (virial) \photometry" traces individual baryonic components star counts bulge, disk luminosity bulge, disk gravitational microlensing bulge emission lines gas [Iocco, MP, Bertone & Jetzer, JCAP11(2011)029] [Iocco, MP, Bertone, submitted] miguel pato (okc stockholm) () 3

5 1. rotation curve: basics v 2 c = r d tot dr sph. = G M (< r ) r miguel pato (okc stockholm) () 4

6 1. rotation curve: basics v 2 c = r d tot dr sph. = G M (< r ) r miguel pato (okc stockholm) () 4

7 1. rotation curve: basics v 2 c = r d tot dr sph. = G M (< r ) r A B R0 terminal velocities local standard of rest miguel pato (okc stockholm) () 4

8 1. rotation curve: basics v 2 c = r d tot dr sph. = G M (< r ) r A B R0 terminal velocities local standard of rest object v0 l R0 Sun Galactic Centre R l.o.s. v l.o.s. LSR = vc (R 0 ) R 0 =R 0 v 0 cos b sin ` Doppler shift 1. gas (21cm, H, CO) 2. stars (H, He, O,...) 3. masers (H 2O, CH 3OH,...) miguel pato (okc stockholm) () 4

9 1. rotation curve: basics v 2 c = r d tot dr sph. = G M (< r ) r A B R0 terminal velocities local standard of rest vc object v0 l R0 Sun Galactic Centre R l.o.s. v l.o.s. LSR = vc (R 0 ) R 0 =R 0 v 0 cos b sin ` Doppler shift 1. gas (21cm, H, CO) 2. stars (H, He, O,...) 3. masers (H 2O, CH 3OH,...) R R miguel pato (okc stockholm) () 5

10 1. rotation curve: basics v 2 c = r d tot dr sph. = G M (< r ) r A B R0 terminal velocities local standard of rest vc object v0 l R0 Sun Galactic Centre R l.o.s. v l.o.s. LSR = vc (R 0 ) R 0 =R 0 v 0 cos b sin ` Doppler shift 1. gas (21cm, H, CO) 2. stars (H, He, O,...) 3. masers (H 2O, CH 3OH,...) R R miguel pato (okc stockholm) () 6

11 1. rotation curve: basics v 2 c = r d tot dr sph. = G M (< r ) r A B R0 terminal velocities local standard of rest vc object v0 l R0 Sun Galactic Centre R l.o.s. v l.o.s. LSR = vc (R 0 ) R 0 =R 0 v 0 cos b sin ` Doppler shift 1. gas (21cm, H, CO) 2. stars (H, He, O,...) 3. masers (H 2O, CH 3OH,...) R R miguel pato (okc stockholm) () 7

12 1. rotation curve: basics terminal vel v 2 c R 0 = r d tot dr sph. = G M (< r ) r gas stars masers 0 object v0 l R0 Sun Galactic Centre vc R R R R/kpc l.o.s. v l.o.s. LSR = vc (R 0 ) R 0 =R 0 v 0 cos b sin ` Doppler shift 1. gas (21cm, H, CO) 2. stars (H, He, O,...) 3. masers (H 2O, CH 3OH,...) miguel pato (okc stockholm) () 8

13 1. rotation curve: basics terminal vel v 2 c R 0 = r d tot dr sph. = G M (< r ) r gas stars masers 0 object v0 l R0 Sun Galactic Centre vc R R R R/kpc l.o.s. v l.o.s. LSR = vc (R 0 ) R 0 =R 0 v 0 cos b sin ` distance Doppler shift 1. terminal velocities (gas) 2. photo-spectroscopy (stars) 3. parallax (masers) miguel pato (okc stockholm) () 9

14 1. rotation curve: basics terminal vel v 2 c R 0 = r d tot dr sph. = G M (< r ) r gas stars masers 0 object R/kpc l.o.s. vc v0 l R0 Sun Galactic Centre R A B R0 terminal velocities local standard of rest R R miguel pato (okc stockholm) () 10

15 1. rotation curve: a new compilation gas stars masers Object type R [kpc] quadrants # objects HI terminal velocities Fich+ ' { 8.0 1,4 149 Malhotra ' { 7.5 1,4 110 McClure-Griths & Dickey ' { HI thickness method Honma & Sofue ' { 20.2 { 13 CO terminal velocities Burton & Gordon ' { Clemens ' { Knapp+ ' { Luna+ ' { HII regions Blitz ' { ,3 3 Fich+ ' { Turbide & Moat ' { Brand & Blitz ' { ,2,3,4 148 Hou+ ' { ,2,3,4 274 giant molecular clouds Hou+ ' { ,2,3,4 30 open clusters Frinchaboy & Majewski ' { ,2,3,4 60 planetary nebulae Durand+ ' { ,2,3,4 79 classical cepheids Pont+ ' { ,2,3,4 245 Pont+ ' { ,3,4 32 carbon stars Demers & Battinelli ' { ,2,3 55 Battinelli+ ' { ,2 35 masers Reid+ ' { ,2,3,4 80 Honma+ ' { 9.9 1,2,3,4 11 Stepanishchev & Bobylev ' Xu+ ' Bobylev & Bajkova ' { 9.4 1,2,4 7 miguel pato (okc stockholm) () 11

16 1. rotation curve: a new compilation coming soon: public code in python user-friendly interface data & parameter selection output rotation curve output positional data [MP & Iocco, in progress] miguel pato (okc stockholm) () 12

17 [Iocco, MP & Bertone, submitted] miguel pato (okc stockholm) () rotation curve: a new compilation optmised to R = 3 20 kpc 2780 individual measurements 2174/506/100 from gas/stars/masers

18 galactic modelling tot = bulge + disk + gas + dm {z} {z } dynamics traces total potential rotation curve R 0:1 30 kpc local stars R R 0 8 kpc (Oort's limit) tracers R kpc (radial Jeans) satellites R kpc (virial) \photometry" traces individual baryonic components star counts bulge, disk luminosity bulge, disk gravitational microlensing bulge emission lines gas 2. [Iocco, MP, Bertone & Jetzer, JCAP11(2011)029] [Iocco, MP, Bertone, submitted] miguel pato (okc stockholm) () 14

19 2. baryons: stellar bulge bulge = 0 f (x ; y; z ) morphology f (x ; y; z ) Stanek+ '97 (E2) e r 0.9:0.4: optical Stanek+ '97 (G2) e r2 s =2 1.2:0.6: optical Zhao '96 e r2 s =2 + r 1:85 a e r a 1.5:0.6: infrared Bissantz & Gerhard '02 e r2 s =(1 + r)1:8 2.8:0.9: infrared Lopez-Corredoira+ '07 Ferrer potential 7.8:1.2: infrared/optical Vanhollebecke+ '09 e r2 s =(1 + r)1:8 2.6:1.8: infrared/optical Robin+ '12 sech 2 ( r s) + e r s 1.5:0.5: infrared normalisation 0 microlensing optical depth: h i = 2:17 +0:47 0: , (`; b) = (1:50 ; 2:68 ) (MACHO '05) miguel pato (okc stockholm) () 15

20 2. baryons: stellar disk disk = 0 f (x ; y; z ) morphology f (x ; y; z ) Han & Gould '03 e R sech 2 (z ) 2.8:0.27 thin optical e R jzj 2.8:0.44 thick Calchi-Novati & Mancini '11 e R jzj 2.8:0.25 thin optical e R jzj 4.1:0.75 thick dejong+ '10 e R jzj 2.8:0.25 thin optical e R jzj 4.1:0.75 thick (R 2 + z 2 ) 2:75=2 1.0:0.88 halo Juric+ '08 e R jzj 2.2:0.25 thin optical e R jzj 3.3:0.74 thick (R 2 + z 2 ) 2:77=2 1.0:0.64 halo Bovy & Rix '13 e R jzj 2.2:0.40 single optical normalisation 0 local surface density: = 38 4M =pc 2 [Bovy & Rix '13] miguel pato (okc stockholm) () 16

21 2. baryons: gas n H = 2n H2 + n HI + n HII morphology Ferriere '12 r < 0:01 kpc M gas M CO, 21cm, H,... Ferriere+ '07 r = 0:01 2 kpc CMZ, holed disk H 2 CO CMZ, holed disk H I 21cm warm, hot, very hot H II disp. meas. Ferriere '98 r = 3 20 kpc molecular ring H 2 CO cold, warm H I 21cm warm, hot H II disp. meas., H Moskalenko+ '02 r = 3 20 kpc molecular ring H 2 CO H I 21cm H II disp. meas. uncertainties CO-to-H 2 factor: X CO = 0:25 X CO = 0:50 1: cm 2 K 1 km 1 s for r < 2 kpc 3: cm 2 K 1 km 1 s for r > 2 kpc [Ferriere+ '07, Ackermann '12] miguel pato (okc stockholm) () 17

22 2. baryons: rotation curve i (x ; y; z )! i (r ; ; ')! v 2 c;i (R) = X i (r ; ; ') = 4G X l;m Y lm (; ') 2l + 1 Z r 1 r l+1 0 ' R d i (R; =2; ') dr i;lm (a)a l+2 da + r l Z 1 r i;lm (a)a 1 l da miguel pato (okc stockholm) () 18

23 2. baryons: rotation curve i (x ; y; z )! i (r ; ; ')! v 2 c;i (R) = X i (r ; ; ') = 4G X l;m full 3d morphology Y lm (; ') 2l + 1 Z r 1 r l+1 X vc;baryons 2 = v 2 c;i 0 ' R d i (R; =2; ') dr i;lm (a)a l+2 da + r l Z 1 r i;lm (a)a 1 l da i miguel pato (okc stockholm) () 18

24 what can we infer about dark matter? [Iocco, MP & Bertone, submitted] miguel pato (okc stockholm) () 19 summary purely observational tot = bulge + disk + gas + dm tot purely observational bulge + disk + gas

25 remark #1: angular velocity miguel pato (okc stockholm) () 20

26 remark #1: angular velocity v l.o.s. LSR = R 0 v c (R) R v 0 cos b sin `.. error of R and v c strongly correlated.. use instead the angular velocity w c v c =R.. this will be the starting point for Fabio miguel pato (okc stockholm) () 20

27 remark #1: angular velocity v l.o.s. LSR = R 0 v c (R) R v 0 cos b sin `.. error of R and v c strongly correlated.. use instead the angular velocity w c v c =R.. this will be the starting point for Fabio miguel pato (okc stockholm) () 21

28 remark #2: how to use the residuals? tot = b + dm #! 2 dm R = d dm( dm ) dr! 2 c =!2 b +!2 dm 1. assume functional dm to \t" and derive constraints [Iocco, MP & Bertone, in progress] 2. extract dm directly [MP & Iocco, in progress] miguel pato (okc stockholm) () 22

29 remark #3: how to improve? breakdown! 2 dm rotation curve bulge disc gas baryonic bracketing relative uncertainty R [kpc ].. R < R 0 : baryonic modelling.. R > R 0 : rotation curve miguel pato (okc stockholm) () 23

30 miguel pato (okc stockholm) () 24