vlbi observations of jets in m87 - indico-fnal (indico) · 2013. 4. 25. · fermi bubbles workshop...

VLBI

observations of jets in

M87

Avery E. Broderick Sheperd Doeleman (MIT Haystack)

Vincent Fish (MIT Haystack)

Alan Rogers (MIT Haystack)

Dimitrios Psaltis (Arizona)

Tim Johannsen (Arizona/UW-PI-CITA)

Avi Loeb (Harvard)

Ramesh Narayan (Harvard)

Mark Reid (Smithsonian)

Mareki Honma (NAOJ)

Fermi Bubbles Workshop 12.4.2013

mm-VLBI


M87






Avi Loeb (Harvard)



Mareki Honma (NAOJ)


mm-VLBI


M87 & Sgr A*






Avi Loeb (Harvard)



Mareki Honma (NAOJ)


SGR A* & M87 ARE THE SAME!

• Very sub-Eddington: 𝑳/𝑳𝑬𝒅𝒅~𝟏𝟎−𝟗 & 𝟏𝟎−𝟔 ≪ 𝟎. 𝟎𝟏

• Flat radio spectrum with spectral break at ~1mm

• Similar 𝒏𝒆, 𝑩~𝟏𝟎𝟎 G


Sgr A*

(Zhao & Goss, 1998)

M87

VLA (NRAO)

What ingredient in jet production is missing in Sgr A*?

(Is an ingredient missing?)

SGR A* & M87 ARE DIFFERENT!


SMA,

JCMT

ARO-SMT

CARMA

APEX,

ASTE,

ALMA Plateau de

Bure

IRAM

30m

SPT

LMT • Earth-sized mm/sub-mm VLBI array

• Existing and Planned telescopes.

• Accesses resolutions of ~10 mas,

Sufficient to resolve horizons of M87 & Sgr A*

Haystack

APEX,

ASTE,

ALMA

SPT


SMA,

JCMT

SMT

CARMA

Data already exists on

Hawaii-CARMA-SMT

• Doeleman et al., Nature, 455, 78 (2008)

𝐷~37 ± 14 𝜇𝑎𝑠~0.7 𝐷𝐻

• Fish et al., ApJ, 727, 36 (2011)

• Doeleman et al., Science, 338, 355 (2012)

FIRST DATA!

SMA,

JCMT

ARO-SMT

CARMA

APEX,

ASTE,

ALMA Plateau de

Bure

IRAM

30m

SPT

LMT

Haystack

APEX,

ASTE,

ALMA

SPT

7 8 9 10 11 12 13

Courtesy of Vincent Fish Fermi Bubbles Workshop 12.4.2013

M87

-

Sgr A* M87

THE STATE OF EHT DATA TODAY


PHYSICAL MODELS FOR LOW-LUMINOSITY AGN Modeling Priors Empirical Priors

SPIN OF SGR A*


PHYSICAL MODELS FOR LOW-LUMINOSITY AGN Modeling Priors Empirical Priors

Low Spin High Spin

SPIN OF SGR A*


GETTING AT SGR A*’S SPIN

a~0+0.64+0.86

q=68+5+8-20-28 deg.

x=-52+17+33-15-24 deg.

Incl

ina

tion

Spin Magnitude

Our accretion

model is wrong!

Observations are easy to fit

Non-accretion physics is

important!


SPIN OF SGR A*


SPIN OF SGR A*

𝜗, 𝜑 , Θ, Φ0 ,

ro, a, dir

SPIN/INCLINATION FROM

DISK LENSE-THIRRING PRECESSION


SPIN OF SGR A*

SGR A*’S NATURAL PRECESSION RATE

𝑇𝑝𝑟𝑒𝑐~𝐿𝑑𝑖𝑠𝑘

𝜏𝐿𝑇~

𝐺𝑀

𝑐3

𝑟𝑖1/2𝑟𝑜

5/2

10 𝑎 sin Θ~

2

𝑎

𝑟𝑜

103

5/2

yr

SPIN OF SGR A*

S2 periapse ~3 × 103 𝐺𝑀/𝑐2

Comparable to timescales

already probed by the EHT!


SPIN-DISK SIZE POSTERIOR PROBABILITY


SPIN OF SGR A*

Sgr A*:

Low spin (if at all)!

MODELING M87: GRMHD JETS

• Blanford-Znajek/Blandford-Payne:

Electromagnetic extraction of black

hole spin/disk angular momentum.

• Large-scale ordered magnetic fields

• Canonical Structure:

• MHD Disk

• Magnetically dominated wind

• Force-free, roughly parabolic jet

McKinney & Blandford (2009)

SPIN OF M87


𝐷 = 40 ± 2 𝜇𝑎𝑠







• MHD Disk




SPIN OF M87


M87 Jet Widths

𝐷 = 40 ± 2 𝜇𝑎𝑠







• MHD Disk




SPIN OF M87


M87 Jet Widths

𝐷 = 40 ± 2 𝜇𝑎𝑠

Hada et al. (2011)

SPIN OF M87: ROUGH CUT

Give non-spinning black holes best chance:

• Jets are disk driven

• Jets turn on (nearly) immediately

Jets start out slow (𝚪~𝟏 − 𝟐), emission scale ~ ISCO

SPIN OF M87

Chris Fach


SPIN OF M87: ROUGH CUT

Give non-spinning black holes best chance:

• Jets are disk driven

• Jets turn on (nearly) immediately

Jets start out slow (𝚪~𝟏 − 𝟐), emission scale ~ ISCO

SPIN OF M87

Chris Fach

EHT size limit








• MHD Disk




SPIN OF M87


“SIMPLE” JET MODELS

• Axisymmetric & Stationary (+poloidal struc)

• Particle inertia irrelevant:

• + Boundary conditions at disk/black hole!

𝑭𝐿 = 𝜌𝑬 + 𝒋 × 𝑩 = 0

SPIN OF M87






𝑭𝐿 = 𝜌𝑬 + 𝒋 × 𝑩 = 0

SPIN OF M87


low RΩ





𝑭𝐿 = 𝜌𝑬 + 𝒋 × 𝑩 = 0

SPIN OF M87


intermediate RΩ




• + Boundary conditions at disk/black hole! 𝜃

Choosing BCs

= choosing Ω(r) & Γ∞

𝑭𝐿 = 𝜌𝑬 + 𝒋 × 𝑩 = 0

SPIN OF M87


tan 𝜃 ~𝑣𝐴

𝑅Ω~

𝐵𝑃

𝐵𝜙~𝛽∞

−1

large RΩ





Choosing BCs

= choosing Ω(r) & Γ∞

𝑭𝐿 = 𝜌𝑬 + 𝒋 × 𝑩 = 0

SPIN OF M87


tan 𝜃 ~𝑣𝐴

𝑅Ω~

𝐵𝑃

𝐵𝜙~𝛽∞

−1

large RΩ

𝜃

Ω

𝑟

High spin

low spin

Disk Friendly!

FULL MHD VS. SIMPLE FORCE FREE

Disk

Wind

Jet


SPIN OF M87

FROM STRUCTURE TO EMISSION

Particle acceleration

in the jet!

AEB & Loeb (2009) Dexter, McKinney & Agol (2012)

SPIN OF M87


RESOLUTION, COOLING TIMES &

PARAMETERIZING IGNORANCE

Cooling

length from

injection at

100 G

Lensed Horizon size

• Particle acceleration

smoothed over jet on EHT

scales!

• Places lower limit on

density of nonthermal

electrons

• Parameterize by typical

load radius, and conserve

thereafter.

SPIN OF M87


EMPIRICAL PRIORS

• Optical super-luminal motion of “knots” (6c at >1”, Γ∞~𝟓)

• Radio super-luminal motion of “knots” (~2.3c at few mas)

• Orientation of large-scale jet (E-W)

• Core Dominance

• Spectra?

Courtesy of Craig Walker

SPIN OF M87


EMPIRICAL PRIORS: SPECTRA OF WHAT?

>1”

0.1”-1”

1 mas-0.1”

<1 mas

SPIN OF M87


EMPIRICAL PRIORS: SPECTRA OF WHAT?

Strong non-VLBI

constraint on jet

models!

>1”

0.1”-1”

1 mas-0.1”

<1 mas

SPIN OF M87


A MODEL FAMILY FOR M87

Load radius

SPIN OF M87


A MODEL FAMILY FOR M87

Load radius Black hole spin

SPIN OF M87


FIRST FITS: EXISTENCE

20

2

10

0

𝜒2

97

102 min 𝜒^2/DOF ~ 97/180!

(cf. Gaussian ~ 130/184!)

Loading

Radius in

𝐺𝑀/𝑐2

Black hole spin Fermi Bubbles Workshop 12.4.2013

FIRST FITS: SOME CHECKS

Loading radius

Jet position angle

(E of N), from

mm-VLBI alone! 𝑃 𝑅, 𝜉

𝑃

~70∘!

SPIN OF M87


FIRST FITS: SOME CHECKS


FIRST FITS: THE SPIN OF M87

M87:

(Very) high spin!

Caution:

spin calibration not

good near a~1

SPIN OF M87


A TALE OF TWO BLACK HOLES

SGR A*

• Low accretion rate RIAF

• Flat radio spectra

+ break at 1mm

• 𝐵~102 G

• Well fit by physically

motivated models

• No prominent jet

• Low spin!

M87


• Low accretion rate RIAF

• Flat radio spectra

+ break at 1mm

• 𝐵~102 G

• Well fit by (surprisingly simple)

physically motivated models

• Prominent jet

• High spin!

First empirical evidence that black

hole spin is important in AGN jets!

vlbi observations of jets in m87 - indico-fnal (indico) · 2013. 4. 25. · fermi bubbles workshop...

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