6. NASA / ESA / STScI / AURA
Saturday, June 8, 2013
7. NASA / ACS Team / Benitez et al.
Saturday, June 8, 2013
8. Virgo Consortium / Volker Springel / Klaus Dolag / Splotch
Saturday, June 8, 2013
9. Virgo Consortium / Volker Springel / Klaus Dolag / Splotch
Saturday, June 8, 2013
10. 100’s to 1000’s of
galaxies
Few Mpc in size
1013-1015 Msolar
85%-90% dark matter
15%-10% baryons
Most baryons not in
galaxies...
CFHT / Coelum Astronomia / Hawaiian Starlight
Perseus Cluster
Cluster Stats
NB: Mpc ~ 1019 km or ~3 million light years
Saturday, June 8, 2013
24. “Tale of Two Cooling
Timescales”
Long cooling time (atmospheres)
Cosmology
Relaxation
Short cooling time (cores)
Galaxy Formation
Feedback
Saturday, June 8, 2013
25. “Tale of Two Cooling
Timescales”
Long cooling time (atmospheres)
Cosmology
Relaxation
Short cooling time (cores)
Galaxy Formation
Feedback
Saturday, June 8, 2013
26. Why study clusters?
Cosmology:
Structure growth as tracer
Cluster number density
Dark matter & dark energy
Complications:
“Weighing” clusters
Cluster dynamic state
Abell 1185
CFHT / Coelum Astronomia / Hawaiian Starlight
Saturday, June 8, 2013
27. Reiprich et al., 2002
Importance of Relaxation
Saturday, June 8, 2013
29. Good news:
Cluster observables related
directly to mass (assuming
equilibrium)
Relations are well
understood & well modeled
Reiprich et al., 2002
Importance of Relaxation
Saturday, June 8, 2013
30. Good news:
Cluster observables related
directly to mass (assuming
equilibrium)
Relations are well
understood & well modeled
Bad news:
Reiprich et al., 2002
Importance of Relaxation
Saturday, June 8, 2013
31. Good news:
Cluster observables related
directly to mass (assuming
equilibrium)
Relations are well
understood & well modeled
Bad news:
Many clusters are not in
equilibrium/relaxed
Precision cosmology
requires knowledge of
cluster dynamic state
Reiprich et al., 2002
Importance of Relaxation
Large dispersion
Saturday, June 8, 2013
32. Importance of Relaxation
Mathiesen & Evrard, 2001
Hotter hard-band
temperatures
Line
of equality
Mathiesen & Evrard
2001 suggested metric
for measuring cluster
dynamic state
Spectroscopically
unresolved, cool,
merging subclusters
alter best-fit cluster
“temperature”
Use bandpass
dependent temperatures
as measure of dynamic
state
Saturday, June 8, 2013
33. ME01 prediction is quite simple to test
Broad-band temperature: 0.7-7.0 keV band
Hard-band temperature: 2.0-7.0 keV band
2.0 keV is in cluster rest frame
Define Hard-band to Broadband Ratio:
THBR =
T2.0−7.0
T0.7−7.0
Importance of Relaxation
Saturday, June 8, 2013
41. Relaxed and Unrelaxed
Distinguish between relaxed and unrelaxed
clusters using complementary indicators
(A) Presence of cool core: quantifiable
using data
(B) Mergers: individual study too time
consuming, consult literature
Saturday, June 8, 2013
42. Assume presence
of cool core (CC)
relates to relaxation
Define a cool core
cluster:
If Tdec < 1 @ 2σ,
cool core
Otherwise, non-cool
T50 kpc
~Tcluster
Tdec =
T50
Tcluster
Relaxed and Unrelaxed
Saturday, June 8, 2013
44. What about merger
systems?
Cull out THBR > 1.1
@ 1σ clusters
Are these mergers?
What of those
unstudied systems?Yepes / Hoeft / UAM
Relaxed and Unrelaxed
Saturday, June 8, 2013
46. Temperature Inhomogeneity
Temperature inhomogeneity is detected &
quantifiable
THBR “knows” about state of cluster core
Highest THBR values associated with mergers
Calibrate between THBR and relaxation using
simulations?
Is THBR useful tool for quantifying scatter in
mass-observables?
Saturday, June 8, 2013
47. Temperature Inhomogeneity
Temperature inhomogeneity is detected &
quantifiable
THBR “knows” about state of cluster core
Highest THBR values associated with mergers
Calibrate between THBR and relaxation using
simulations?
Is THBR useful tool for quantifying scatter in
mass-observables?
ASK DAVID VENTIMIGLIA AT HIS DEFENSE?
Saturday, June 8, 2013
48. “Tale of Two Cooling
Timescales”
Long cooling time (atmospheres)
Cosmology
Relaxation
Short cooling time (cores)
Galaxy Formation
Feedback
Saturday, June 8, 2013
49. “Tale of Two Cooling
Timescales”
Long cooling time (atmospheres)
Cosmology
Relaxation
Short cooling time (cores)
Galaxy Formation
Feedback
Saturday, June 8, 2013
50. Galaxy Labs, Inc.:
ICM “records” feedback
Function of black holes /AGN
Star formation in big galaxies
Complications:
Theory & observation don’t
agree on massive galaxy
properties
Details of feedback poorly
understood
X-ray: NASA / CXC / UVic. / A.Mahdavi et al.
Optical / Lensing: CFHT / UVic. / A.Mahdavi et al
Abell 520
Why study clusters?
Saturday, June 8, 2013
51. Importance of Feedback
Zwicky 3146
“The Most Massive Cooling Flow”
Edge et al., 1994
˙M > 1200 M⊙ yr−1
Edge et al., 1994
Let us consider simple
cluster model...
Without heating, models
predict large deposition of
cool gas into core
BCG properties
inconsistent with this
model
AND...
Saturday, June 8, 2013
52. Importance of Feedback
TX <
1
3
Tvirial
Peterson et al., 2001, 2003
X-ray spectroscopy
disproves simple
cooling-flow model
No
gas
Also, not enough
mass in cooled by-
products
Molecular gas
Emission line nebulae
Young stars
Saturday, June 8, 2013
53. Galaxy population also
says there is more to
story
Theory & observation
do not fully agree on
galaxy properties
Massive galaxies too
blue & too bright
All factors point to
halted cooling
Learn about high-z
processes via low-z
feedback in cores
Importance of Feedback
Croton et al., 2006
NO
FEEDBACKWITHFEEDBACK
Saturday, June 8, 2013
54. What could possibly be
heating the cores of
clusters?
Saturday, June 8, 2013
56. Importance of Feedback
X-ray: NASA / CXC / Blanton
X-ray: NASA / CXC / Wilson & Young
Radio: NRAO
Abell 2052
Cygnus A
Saturday, June 8, 2013
57. Importance of Feedback
X-ray: NASA / CXC / Blanton
X-ray: NASA / CXC / Wilson & Young
Radio: NRAO
X-ray: NASA / CXC / SAO
Radio: NRAO / Greg Taylor
Abell 2052
Cygnus A
Hydra A
Saturday, June 8, 2013
58. Importance of Feedback
X-ray: NASA / CXC / Blanton
X-ray: NASA / CXC / Wilson & Young
Radio: NRAO
X-ray: NASA / CXC / SAO
Radio: NRAO / Greg Taylor
X-ray: NASA / CXC / IoA / Fabian et al.
Abell 2052
Cygnus A
Hydra A
Abell 426
Saturday, June 8, 2013
59. Importance of Feedback
Take a “close to the data” approach:
Study cooling ICM & cluster cores
Better understand feedback
Create broad, varied cluster sample from
Chandra archive
Conduct study of ICM entropy... entropy?
Saturday, June 8, 2013
62. ICM Entropy
Consider entropy as a
state variable:
dS =
dQ
T
Ideal gas equation of state:
P = Kρ5/3
Nature.Wallpaperme.com
Saturday, June 8, 2013
63. ICM Entropy
Consider entropy as a
state variable:
dS =
dQ
T
Recast using observables:
K =
TX
n
2/3
elec
Ideal gas equation of state:
P = Kρ5/3
Nature.Wallpaperme.com
Saturday, June 8, 2013
64. ICM Entropy
Consider entropy as a
state variable:
dS =
dQ
T
Recast using observables:
K =
TX
n
2/3
elec
Ideal gas equation of state:
P = Kρ5/3
Nature.Wallpaperme.com
True thermo entropy:
s =
3
2
k ln K + s0
Saturday, June 8, 2013
65. ICM Entropy
Consider entropy as a
state variable:
dS =
dQ
T
Recast using observables:
K =
TX
n
2/3
elec
Ideal gas equation of state:
P = Kρ5/3
dK
dr
≥ 0
Nature.Wallpaperme.com
True thermo entropy:
s =
3
2
k ln K + s0
Saturday, June 8, 2013
66. DM halo properties and entropy
structure dictate X-ray observables
Shock heating and cooling will alter
entropy distribution
Entropy will retain information about
feedback
Entropy may also hold clues about
how feedback operates
Study entropy in cluster cores…
ICM Entropy
Saturday, June 8, 2013
67. ICM Entropy
Mined Chandra
Data Archive (CDA)
Inspected or
analyzed *every*
cluster obs in CDA
8.2 Msec;
302 observations;
233 “clusters”
Make full-body of
work publicly
available
The ACCEPT Collection
Saturday, June 8, 2013
68. Deriving ICM Entropy
Extract surface
brightness
Emergent X-rays
indicative of gas density:
Assume spherical
symmetry
Deproject emission
Convert surface
brightness to density
ff ∝ ρ2
T1/2
Saturday, June 8, 2013
69. Deriving ICM Entropy
Extract surface
brightness
Emergent X-rays
indicative of gas density:
Assume spherical
symmetry
Deproject emission
Convert surface
brightness to density
ff ∝ ρ2
T1/2
Saturday, June 8, 2013
70. Deriving ICM Entropy
Extract surface
brightness
Emergent X-rays
indicative of gas density:
Assume spherical
symmetry
Deproject emission
Convert surface
brightness to density
ff ∝ ρ2
T1/2
Saturday, June 8, 2013
71. Deriving ICM Entropy
Extract temperature
profile
Minimum three annuli
with 2500 counts each
Fit spectra with single-
component, absorbed,
thermal model
No spectral
deprojection: time
consuming, not
significant
Saturday, June 8, 2013
72. Deriving ICM Entropy
Extract temperature
profile
Minimum three annuli
with 2500 counts each
Fit spectra with single-
component, absorbed,
thermal model
No spectral
deprojection: time
consuming, not
significant
Saturday, June 8, 2013
73. 2D Maps from Schuecker et al., 2004
Coma Cluster
TX nelec
Deriving ICM Entropy
Saturday, June 8, 2013
74. 2D Maps from Schuecker et al., 2004
Coma Cluster
K =
TX
n
2/3
elec
Deriving ICM Entropy
Saturday, June 8, 2013
75. 2D Maps from Schuecker et al., 2004
Coma Cluster
K =
TX
n
2/3
elec
Deriving ICM Entropy
Saturday, June 8, 2013
76. Deriving ICM Entropy
Fit models to K(r):
K(r) = K0 + K100
r
100 kpc
α
K(r) = K100
r
100 kpc
α
Saturday, June 8, 2013
77. Deriving ICM Entropy
Fit models to K(r):
K(r) = K0 + K100
r
100 kpc
α
K(r) = K100
r
100 kpc
α
Repeat 230+ times...
Saturday, June 8, 2013
81. Entropy profiles deviate
from power-law
Converge to pure
cooling model at large
radii
Non-Zero Core Entropy
Saturday, June 8, 2013
82. Entropy profiles deviate
from power-law
Converge to pure
cooling model at large
radii
Non-zero core entropy
consistent with
episodic heating
Non-Zero Core Entropy
Saturday, June 8, 2013
83. Entropy profiles deviate
from power-law
Converge to pure
cooling model at large
radii
Non-zero core entropy
consistent with
episodic heating
Is there more here than
meets the eye?
Non-Zero Core Entropy
Saturday, June 8, 2013
86. Does star formation “know”
about K0?
Select robust tracer like Hα:
UV ionizing radiation from O
and B stars
Turbulent mixing layers?
Conduction interfaces?
Regardless, Hα indicates T ~
104 K gas
Scour the literature…
InstituteforAstronomy/L.Cowieetal.
Feedback-K0 Relations
Abell 1795
Saturday, June 8, 2013
89. Do AGN “know” about K0?
Select robust tracer like radio
emission:
Assumed to be sign of AGN
Radio relics/ghosts, halos,
lobes… mostly AGN related
Query NVSS and SUMSS
Sidestep resolution issues
with redshift cut
NASA / CXC / D. Berry
Feedback-K0 Relations
Saturday, June 8, 2013
90. Do AGN “know” about K0?
Select robust tracer like radio
emission:
Assumed to be sign of AGN
Radio relics/ghosts, halos,
lobes… mostly AGN related
Query NVSS and SUMSS
Sidestep resolution issues
with redshift cut
NRAO / AUI / Taylor
3C 353
Feedback-K0 Relations
Saturday, June 8, 2013
93. Entropy threshold
is back
Feedback-K0 Relations
Common threshold suggests
common mechanism, like thermal
electron conduction
(Voit et al., 2008)
Saturday, June 8, 2013
94. So where does that
leave us…
Entropy Lifecycle
(speculative)
Saturday, June 8, 2013
100. Conclusions
Hard-band to broadband temperature ratio
correlates with cluster dynamic state
ICM entropy properties consistent with AGN
feedback models
Characteristic entropy threshold for feedback
activity
Saturday, June 8, 2013