2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 1/20 Study of Faraday Rotation d ue to the Intergalactic Mag netic Field ~Preparing the Era of the Square Kilometer Array~ Takuya Akahori, Dongsu Ryu Chungnam National University 2.0 1.0 Log 10 |RM| [rad m -2 ] -50 -25 0 25 50 [h -1 Mpc]
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Takuya Akahori, Dongsu Ryu Chungnam National University
2.0 1.0 0.0 -1.0 -2.0. Log 10 |RM| [rad m -2 ]. -50 -25 0 25 50 [h -1 Mpc]. Study of Faraday Rotation due to the Intergalactic Magnetic Field ~Preparing the Era of the Square Kilometer Array~. Takuya Akahori, Dongsu Ryu Chungnam National University. - PowerPoint PPT Presentation
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2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 1/20
Study of Faraday Rotation due to the Intergalactic Magnetic Field~Preparing the Era of the Square Kilometer Array~
Takuya Akahori, Dongsu Ryu
Chungnam National University
2.0
1.0
0.0
-
1.0
-
2.0
Log10 |RM| [rad m-2]
-50 -25 0 25 50[h-1Mpc]
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 2/20
• Modeling of magnetic field and its power spectrum– Feretti+ (95), Felton (96), Krause+ (09)– Vogt, Ensslin (03; 05), Murgia+ (04), Guidetti+ (08), Bonafede+ (10)
• Simulations and estimation of RM in the LSS– Kulsrud+ (97), Ryu , Kang, Biermann (98), Dolag+ (99; 05), Dubios. Teyssier (08),
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 9/20
1 Present-day local universe: 2D map
• RM ~100 (GCs), ~10 (Groups), ~0.01-1 (filaments)• Mixture of positive and negative RM, that reflects the rand
omness and the coherence scale of IGMFs in the LSS
2.0
1.0
0.0
-1.0
-
2.0
Log10 |RM| [rad m-2]
-50 -25 0 25 50[h-1Mpc]
(z=0, L=100 h-1 Mpc)
-10 -5 0 5 10[h-1Mpc]
Log10 |RM| [rad m-2]
10.
5.0
0.0
-
5.0
-
10.
RM[rad m-2]
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 10/20
1 Present-day local universe: radial profile
• Inducement of RM is a random walk process with the coherence length < path length, but is dominated by the contribution from the density peak along LOS
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 11/20
1 Present-day local universe: statistics
・ Lognormal profile of PDF・ rms ~ 1.4 [rad m-2] for WHIM
PDF of |RM| for WHIM (105 K<Tx<107 K)Tx: emissivity weighted temperature. Black: 3×16 runs, Red: average, Blue: best-fit
・ Peaked at ~Mpc scale・ PRM(k) is close to PB||,proj
(k): RM traces B well
2D power spectra of RM and the projected IGMFBlack: 3×16 runs, Red: average
100 h-1 10 h-1 1 h-1Mpc 10 h-1 1 h-1Mpc↑ in good agreement with Cho, Ryu (09)
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 12/20
2 Cosmological effects: RM stacking
• |RM| increases with integrating RM along LOS
Simulation boxes are stacked up to z=5Redshift distribution of radio sources are considered
Willman+ (08)
z=0.1 0.3 0.5 1.0 3.0 5.0
Log |RM|[rad m-2]
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 13/20
2 Cosmological effects: statistics
• rms of RM
• PDF– lognormal
[rad m-2]
WHIM+ICM 40WHIM (theoretical) 7-10
WHIM (observational) 6-10
rms of RM integrated up to z. ICM candidates are subtracted in the integration (theoretical) or after the integration (observational) of RM
★ observational
T [K]
107
★ theoreticalTx=4keV
Tx=1.5keV
ALL
CLS
1Mpc
TM7
T57 Map Pixcels w Tx>107K
TS8 MapPixcels w Tx>107K
& Sx>10-8 e/s/cm2/sr
TS0 MapPixcels w Tx>107K
& Sx>10-10e/s/cm2/sr
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 14/20
2 Cosmological effects: statistics
• P(k): peak scale at ~0.2º• S2(r): characteristic scale at ~0.1-0.2º
2D power spectra P(k) integrated up to z=0.05, 0.3, 5 (thin to thick)
2nd order structure function S2(r)
1.4º 0.14º
~0.2º
2010.08.20 SKA-KR Workshop 2010, KASI, Daejeon, Korea Akahori 15/20
All sky RM (Taylor+ 09)
• Galactic RM is a serious contamination for studying RM in filaments– galactic RM ~10-100 [rad m-2]