Coma

200 kpc

A2319

200 kpc

GALAXY CLUSTER GAS MOTIONS WITH X-RAY SURVEYOR:

PROBING THE SMALL SCALES

John ZuHone, MIT Kavli Institute

6.4 6.5 6.6

0.1

110

norm

aliz

ed c

ount

s s−

1 keV

−1

Energy (keV)

data and folded model

sekiya 6−Jun−2011 12:36

vturb = 0 km/svturb = 100 km/svturb = 300 km/svturb = 1000 km/s

6.7

w

xyz

jk

e

po

Perseus simulated spectrum (wabs＊bapec)

He-like Fe line at E0 ≈ 6.7 keV

ASTRO-H

• 3’x3’ FOV

• ~5 eV spectral resolution

• ~1’ spatial PSF

X-RAY SURVEYOR

• 5’x5’ FOV

• ≲ 5 eV spectral resolution

• ~1” spatial PSF

TURBULENCE IN COMAComa

200 kpc

ZuHone, Markevitch, & Zhuravleva 2015 (arXiv:1505.07848)

WHY COMA?

Churazov et al 2012

• bright and nearby

• large core radius

• no central AGN

• likely to be turbulent

Inertial Range

Dissipation Scale

Injection Scale P(k) ~ k-α

k

P(k)

3’x3’

1.5’ ≈ 40 kpc

“strip” “big cross” “small cross”

“fill” “checkerboard”

arXiv:1505.07848

ERRORS• cosmic variance errors

• Natural variations in the velocity field

• Decrease with more baselines

• measurement errors

• Statistical errors on line shift and width from Poisson statistics (increase with increasing line width, decrease with increasing exposure)

• Systematic errors on the line shift from gain uncertainty

VARYING INJECTION

SCALES

arXiv:1505.07848

VARYING DISSIPATION

SCALESCurves are essentially

indistinguishable

arXiv:1505.07848

10 kpc 20 kpc

100 kpc50 kpc

5’x5’

1” ≈ 0.5 kpc

σstat = 0 km/s σstat = 20 km/s

POWER SPECTRA Reblocked to 4”x4” pixels

M = 0.3

σstat = 40 km/s σstat = 80 km/s

POWER SPECTRA Reblocked to 4”x4” pixels

M = 0.3

SLOSHINGA2319

200 kpc

ZuHone, Miller, Simionescu, & Bautz 2015 (arXiv:1508.04426)

LOOKING ONTO THE

PLANE

SB T

σμarXiv:1508.04426

LOOKING INTO THE

PLANE

SB T

σμarXiv:1508.04426

DIGGING INTO THE VELOCITY FIELD

SIMULATED SPECTRA

Model: Thermal broadening only

exposure time = 200 ks

Model: Thermal and Gaussian

velocity broadening

exposure time = 200 ks

arXiv:1508.04426

PSF SCATTERING

arXiv:1508.04426

VELOCITY DISTRIBUTIONS: ASTRO-H

arXiv:1508.04426 (cheating! ignored PSF scattering)

VELOCITY DISTRIBUTIONS: X-RAY SURVEYOR

BUT WHY X-RAY SURVEYOR?

• < 1” resolution of Chandra resulted in discovery of cold fronts

• Need nearly equivalent resolution to study thermodynamic and kinematic properties near interface

SUMMARY• With Astro-H, we will finally start to get a handle on gas kinematics in galaxy

clusters

• But limited resolution will only get us so far—just the basic properties of the velocity field on large scales

• With an X-ray Surveyor:

• We can potentially get at the dissipation scale in Coma, so long as we can keep the measurement errors down

• Larger effective area and higher spatial resolution would enable us to more precisely nail down the characteristics of the velocity field in sloshing cores