The Size of the Jet Launching Region in M87

Transcription

1 The Size of the Jet Launching Region in M87 Jason Dexter TAC Postdoctoral Fellow UC Berkeley With Eric Agol and Jonathan McKinney

2 M87 Center of Virgo Cluster Ultra relagvisgc jet Largest in angular size Hubble 7mm Junor et al. (1999) 2cm Kovalev et al. (2007) 2

3 M87 Best target for studying jet launching region BH: 6x10 9 M sun, R s 10 μas (Gebhardt et al. 2009) 800x500 R s 43 GHz Craig Walker 3

4 M87 Super luminal mogon: i = deg Bereba et al. (1999) 4

5 Where is the Black Hole? Hada et al. (2011) 5

6 Core Shids Point to BH? MulG frequency VLBI: jet originates in radio core (Hada et al. 2011) 6

7 Sub millimeter VLBI Doeleman et al. (2012) v (km) u (km) Doeleman et al. (2009), Broderick & Loeb (2009) Event Horizon Telescope (arxiv: ), hbp:// 7

8 Disk/Jet Models of M87 Semi analygc disk and/or jet (e.g., Reynolds et al. 1996, Di Mabeo et al. 2003, Broderick & Loeb 2009) MHD jet simulagons (e.g., Zakamska+2008, Gracia +2006, Porth+2011) 11/30/12 di Mabeo et al. (2003) Binary Black Holes and Dual AGN Porth et al. (2011) 8

9 The MRI & GRMHD MRI (Balbus & Hawley 1991): Weakly magnegzed fluid with Keplerian rotagon is unstable Ang mom transport & accregon GRMHD simulagons Physical accregon theory Time dependent, fully relagvisgc LimitaGons: Numerical & difficult RadiaGon & thermodynamics Dynamic range & duragon IniGal condigons Gammie et al. (2004)

10 Jonathan McKinney 10

11 GRMHD SimulaGons 3D, Gme dependent GRMHD great for mm Sgr A* and M87 Thick, compact emission region Insignificant cooling(?) Moscibrodzka et al. (2009) Not perfect Collisionless plasma (mfp = 10 4 R s ) No electrons! 11

12 Ray Tracing Assume light rays are geodesics geokerr, Dexter & Agol (2009) SimulaGon: McKinney & Blandford (2009) Electrons Disk: constant T i /T e, Jet: power law Synchrotron emission Thermal: Leung et al. (2011) PL: Yuan et al. (2003), Dexter (2011) Schnittman et al. (2006) 12

13 Black Hole Shadow Photon sphere causes shadow Bardeen (1973); Dexter & Agol (2009)

14 Black Hole Images & Shadows Bardeen (1973); Dexter & Agol (2009) Broderick & Loeb (2009) SensiGve to viewing geometry & details of accregon flow Need accurate theoregcal predicgons! Falcke, Melia & Agol (2000) Bromley, Melia & Liu (2001) 14

15 Disk Images 100x100 µas Dexter et al. (2009, 2010) 15

16 Modeling M87 McKinney & Blandford (2009) GRMHD stargng to do relagvisgc magnegzed jets Electrons: disk/jet, emission: synchrotron MagneGc jet, let ujet=ηb2 n(γ)=aγ p, γ > γmin Inner radii only 11/30/12 Binary Black Holes and Dual AGN 16

17 GRMHD M87 Models RepresentaGve models: Disk/jet or jet Unlike previous models Can t have disk peak in radio Can t match radio at all! (similar to Sgr A*) Broderick & Loeb ( 2009) Jet (J2) Disk/jet (DJ1) 17

18 Jet Images 100x100 µas Dexter, McKinney, Agol (2012) 18

19 M87 Images & VisibiliGes Images are sgll crescents! Gaussian size: μas (flux, viewing, model) Shadow on Hawaii Mexico or Mexico Chile Shadow Dexter et al. (2012) 19

20 The Size of M87 Doeleman et al. (2012) Size = 40 μas Size = μas 20

21 M87 Imaging No scabering, long Gmescales! Baron & Monnier (U. Mich) Broderick et al. Dexter et al. (2012) Original 4 stagons 7 stagons 21

22 Open TheoreGcal QuesGons What powers jets: BH spin or disk? Fender et al. (2010), Narayan & McClintock (2012) What happens when the disk is misaligned? Fragile et al. (2007, 2008, 2009); McKinney et al. (2012) What happens in a binary? (Palenzuela et al. 2010) What is the jet pargcle distribugon? 22

23 Jet Power vs. BH Spin Either no or strong correlagon depending on what you measure Fender et al. (2010) Narayan & McClintock (2012) Hard state radio normalisation Hard state radio normalisation Spin measurement reflection fits Spin measurement disc fits Hard state near IR normalisation Hard state near IR normalisation Spin measurement reflection fits Spin measurement disc fits 23

24 Tilted Jets? For low luminosity sources don t expect alignment: where does jet point? Bardeen & Peberson (1975) Fragile et al. (2007) 24

25 Tilted Jets? Coherent, vergcal B: jet aligns disk! McKinney et al. (2012) 25

26 Constraining Jet Physics Compare models to data to test MHD jets, constrain mass loading Broderick & Loeb (2009) y (mas) x (mas) 26

27 Summary M87 is a unique laboratory for jet physics MulG wavelength, VLBI Event Horizon Telescope resolving jet launching region! GRMHD models of M87 Counter jet images Correctly predicted μas size Robust results for compact, opt. thin emission Reasonable chance of detecgng BH shadow in next 5 10 years Future: mass loading, test MHD jet theory 27

28 Event Horizon Telescope From Shep Doeleman s Decadal Survey Report on the EHT UV coverage (Phase I: black) Doeleman et al (2009) 28

29 Event Horizon Scale Emission Incredible opportunity for BH astrophysics Doeleman et al. (2008) EHT science requires modeling All results modeldependent for foreseeable future Shadow Gaussian FWHM ~4 R s 29

30 GRMHD M87 Models RepresentaGve models: Disk/jet or jet Unlike previous models Can t have disk peak in radio Can t match radio at all Broderick & Loeb ( 2009) 30