Gamma-Ray Bursts are precise distance indicators similar to Type Ia Supernovae?
Ryo Tsutsui, Takashi Nakamura, Daisuke Yonetoku, Keitaro Takahashi, Yoshiyuki Morihara
Abstract
We estimate the distance modulus to long gamma-ray bursts (LGRBs) using the Type I Fundamental Plane, a correlation between the spectral peak energy
E
p
, the peak luminosity
L
p
, and the luminosity time
T
L
(
≡
E
iso
/
L
p
where
E
iso
is isotropic energy) for small Absolute Deviation from Constant Luminosity(ADCL). The Type I Fundamental Plane of LGRBs is calibrated using 8 LGRBs with redshift
z<1.4
. To avoid any assumption on the cosmological model, we use the distance modulus of 557 Type Ia supernovae (SNeIa) from the Union 2 sample. This calibrated Type I Fundamental Plane is used to measure the distance moduli to 9 high-redshift LGRBs with the mean error
σ
¯
μ
=0.31
, which is comparable with that of SNe Ia
σ
¯
μ
=0.26
where
μ
stands for the distance modulus. The Type I Fundamental Plane is so tight that our distance moduli have very small uncertainties. From those distance moduli, we obtained the constraint
Ω
M
=0.22±0.04
for flat
Λ
CDM universe. Adding 9 LGRBs distance moduli (
z>1.4
) to 557 SNeIa distance moduli (
z<1.4
) significantly improves the constraint for non-flat
Λ
CDM universe from (
Ω
M
,
Ω
Λ
)=(
0.29±0.10
,
0.76±0.13
) for SNeIa only to (
Ω
M
,
Ω
Λ
)=(
0.23±0.06
,
0.68±0.08
) for SNeIa and 9 LGRBs.