机构:
Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Univ Roma La Sapienza, Ist Nazl Fis Nucl, I-00185 Rome, ItalyUniv Oxford, Subdept Astrophys, Oxford OX1 3RH, England
Archidiacono, Maria
[2
,3
]
Melchiorri, Alessandro
论文数: 0引用数: 0
h-index: 0
机构:
Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Univ Roma La Sapienza, Ist Nazl Fis Nucl, I-00185 Rome, ItalyUniv Oxford, Subdept Astrophys, Oxford OX1 3RH, England
Melchiorri, Alessandro
[2
,3
]
论文数: 引用数:
h-index:
机构:
Ratra, Bharat
[4
]
机构:
[1] Univ Oxford, Subdept Astrophys, Oxford OX1 3RH, England
[2] Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
[3] Univ Roma La Sapienza, Ist Nazl Fis Nucl, I-00185 Rome, Italy
[4] Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA
GAS MASS FRACTION;
COSMOLOGICAL CONSTRAINTS;
MEDIAN STATISTICS;
HUBBLE CONSTANT;
POWER SPECTRUM;
FIELD;
PARAMETERS;
TELESCOPE;
EVOLUTION;
ENERGY;
D O I:
10.1103/PhysRevD.86.043520
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
Recent analyses that include cosmic microwave background (CMB) anisotropy measurements from the Atacama Cosmology Telescope and the South Pole Telescope have hinted at the presence of a dark radiation component at more than two standard deviations. However, this result depends sensitively on the assumption of an Hubble Space Telescope prior on the Hubble constant, where H-0 = 73.8 +/- 2.4 km/s/Mpc at 68% c.l.. Here we repeat this kind of analysis assuming a prior of H-0 = 68 +/- 2.8 km/s/Mpc at 68% c.l., derived from a median statistics (MS) analysis of 537 non-CMB H-0 measurements from Huchra's compilation. This prior is fully consistent with the value of H-0 = 69.7 +/- 2.5 km/s/Mpc at 68% c.l. obtained from CMB measurements under assumption of the standard ACDM model. We show that with the MS H-0 prior the evidence for dark radiation is weakened to similar to 1.2 standard deviations. Parametrizing the dark radiation component through the effective number of relativistic degrees of freedom N-eff, we find N-eff 3.98 +/- 0.37 at 68% c.l. with the Hubble Space Telescope prior and N-eff 3.52 +/- 0.39 at 68% c.l. with the MS prior. We also discuss the implications for current limits on neutrino masses and on primordial Helium abundances.
机构:
Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Univ Roma La Sapienza, INFN, I-00185 Rome, ItalyUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Calabrese, Erminia
;
Huterer, Dragan
论文数: 0引用数: 0
h-index: 0
机构:
Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USAUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Huterer, Dragan
;
Linder, Eric V.
论文数: 0引用数: 0
h-index: 0
机构:
Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA
Ewha Womans Univ, Inst Early Univ WCU, Seoul, South KoreaUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Linder, Eric V.
;
Melchiorri, Alessandro
论文数: 0引用数: 0
h-index: 0
机构:
Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Univ Roma La Sapienza, INFN, I-00185 Rome, ItalyUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Melchiorri, Alessandro
;
Pagano, Luca
论文数: 0引用数: 0
h-index: 0
机构:
CALTECH, Jet Prop Lab, Pasadena, CA 91109 USAUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
机构:
Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Univ Roma La Sapienza, INFN, I-00185 Rome, ItalyUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Calabrese, Erminia
;
Huterer, Dragan
论文数: 0引用数: 0
h-index: 0
机构:
Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USAUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Huterer, Dragan
;
Linder, Eric V.
论文数: 0引用数: 0
h-index: 0
机构:
Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA
Ewha Womans Univ, Inst Early Univ WCU, Seoul, South KoreaUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Linder, Eric V.
;
Melchiorri, Alessandro
论文数: 0引用数: 0
h-index: 0
机构:
Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Univ Roma La Sapienza, INFN, I-00185 Rome, ItalyUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy
Melchiorri, Alessandro
;
Pagano, Luca
论文数: 0引用数: 0
h-index: 0
机构:
CALTECH, Jet Prop Lab, Pasadena, CA 91109 USAUniv Roma La Sapienza, Dept Phys, I-00185 Rome, Italy