probing the curvature and dark energy
DESCRIPTION
Probing the curvature and dark energy. Gong, Yungui 龚云贵 Chongqing University of Posts and Telecommunications 重庆邮电学院. “ 宇宙暗物质和暗能量”研讨会, 2005 年 7 月 8 日. Dark Energy Introduction Current Status of Parameterizations One-parameter Parameterization Conclusion. Why Dark Energy?. - PowerPoint PPT PresentationTRANSCRIPT
Probing the curvature and dark energy
Gong, Yungui
龚云贵
Chongqing University of Posts and Telecommunications
重庆邮电学院
“宇宙暗物质和暗能量”研讨会, 2005 年 7 月 8日
• Dark Energy Introduction
• Current Status of Parameterizations
• One-parameter Parameterization
• Conclusion
Why Dark Energy? 03.175
98.0
46.0
2
26.031.0
15.017.00
m
Model independent method
• Taylor expansion of Hubble parameter, M. Visser, CQG 21 (2004) 2603
• Prameterizations of energy density: 2nd Order Polynomial, U. Alam etal. MNRAS 354 (2004) 275
• Negative Power Polynomial, U. Alam etal. MNRAS 354 (2004) 275
1))1()1((3
)1(2)1(,)1()1(
2210
2212
210
zAzAA
zAzAzAzAA QQ
1))1()1()1((3
)1()1(,)1()1/(
31
201
13
1110
zBzBzB
zBzBzBzBB QQ
Common Parameterization of WQ
• Constant equation of state w
• Linear equation of state w=w0+w1z
• Stable Parameterizations
• Wetterich Parameterization
• Parameterization
20)))1ln(1/(1(3
0 ))1ln(1(,)1( 0
zbz Q
zbQQ
z
zez a
Qzz
QQaa
1,)1( 0)1/(3)1(3
00
)1ln(1,))1ln(1()1( 0/33
00
zbzbz Q
bQQ
20)1(2/3)1(3
0 )1(,)1(
220
z
zez a
Qzz
QQa
H.K. Jassal, MNRAS 356(2005) L11
Fitting Results
• Taylor expansion of Hubble parameter
Y. Gong, astro-ph/0405446 , Class. Quantum Grav. 22 (2005) 2121
1))1()1((3
)1(2)1(,)1()1(
2210
2212
210
zAzAA
zAzAzAzAA QQ
1))1()1()1((3
)1()1(,)1()1/(
31
201
13
1110
zBzBzB
zBzBzBzBB QQ
z
zez a
Qzz
QQaa
1,)1( 0)1/(3)1(3
00
20)1(2/3)1(3
0 )1(,)1(
220
z
zez a
Qzz
QQa
20)))1ln(1/(1(3
0 ))1ln(1(,)1( 0
zbz Q
zbQQ
)1ln(1,))1ln(1()1( 0/33
00
zbzbz Q
bQQ
Supernova Fit to dark energy
One parameter Parameterization
z
wzw
1
)( 0
zzez
wzw
1/0
1)(
Y. Gong and Y.Z. Zhang, astro-ph/0502262
4.175
2.01.1
05.001.0
05.025.0
2
0
0
0
wk
m
z
wzw
1
)( 0
5.176
97.0
001.0
04.028.0
2
17.019.00
046.0045.00
0
w
k
m
zzez
wzw
1/0
1)(
Results
Summary
Thanks!