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arXiv 0809.0657astro-phgr-qchep-ph
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与模型无关的伽马射线暴距离测量和对暗能量的限制

Model-Independent Distance Measurements from Gamma-Ray Bursts and Constraints on Dark Energy

Yun Wang

摘要:

伽马射线暴(GRB)是宇宙中能量最大的事件,通过测量宇宙膨胀历史(红移大于6),提供了对暗能量的补充探测。与Ia型超新星(SNe Ia)不同,伽玛暴必须在每一个宇宙学模型中进行校准,因为缺乏附近的伽玛暴样本进行模型独立校准。对于一个具有宇宙学常数的平坦宇宙,我们仅从69个伽玛暴中得到Omega_m=0.25^{+0.12}-0.11}。我们表明,目前的伽玛射线暴数据可以概括为一组模型无关的距离测量,可以忽略不计的信息损失。我们约束的暗能量状态方程的宇宙尺度因子线性使用这些距离测量伽玛暴,连同“联盟”汇编的超新星Ia,WMAP五年的观测,和SDSS重子声学振荡尺度测量。我们发现,一个宇宙学常数是符合目前的数据在68%的置信水平,一个平坦的宇宙。我们的结果提供了一个简单而强大的方法,将伽玛暴数据的宇宙学数据的联合分析,以约束暗能量。

英文摘要:

Gamma-Ray Bursts (GRB) are the most energetic events in the Universe, and provide a complementary probe of dark energy by allowing the measurement of cosmic expansion history that extends to redshifts greater than 6. Unlike Type Ia supernovae (SNe Ia), GRBs must be calibrated for each cosmological model considered, because of the lack of a nearby sample of GRBs for model-independent calibration. For a flat Universe with a cosmological constant, we find Omega_m=0.25^{+0.12}_{-0.11} from 69 GRBs alone. We show that the current GRB data can be summarized by a set of model-independent distance measurements, with negligible loss of information. We constrain a dark energy equation of state linear in the cosmic scale factor using these distance measurements from GRBs, together with the "Union" compilation of SNe Ia, WMAP five year observations, and the SDSS baryon acoustic oscillation scale measurement. We find that a cosmological constant is consistent with current data at 68% confidence level for a flat Universe. Our results provide a simple and robust method to incorporate GRB data in a joint analysis of cosmological data to constrain dark energy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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