分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： A large number of galactic binary systems emit gravitational waves (GW) continuously with frequencies below $\sim$10 mHz. The LISA mission could identify the tens of thousands of binaries over years of observation and will be subject to the confusion noise around 1 mHz yielded by the unresolved sources. Beyond LISA, there are several missions have been proposed to observe GWs in the sub-mHz range where the galactic foreground is expected to be overwhelming the instrumental noises. In this study, we investigate the detectability of sub-mHz GW missions to detect the galactic double white dwarf (DWD) binaries and evaluate the confusion noise produced by the undistinguished DWDs. This confusion noise could also be viewed as a stochastic GW foreground and be effectively observed in the sub-mHz band. The parameter determinations for the modeled foreground are examined by employing different detector sensitivities and population models. By assuming the determined foregrounds could be subtracted from the data, we evaluate the residuals which are expected to have power spectral densities two orders of magnitude lower than the originals data.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： For the stochastic gravitational wave backgrounds (SGWBs) search centred at the milli-Hz band, the galactic foreground produced by white dwarf binaries (WDBs) within the Milky Way contaminates the extra-galactic signal severely. Because of the anisotropic distribution pattern of the WDBs and the motion of the spaceborne gravitational wave interferometer constellation, the time-domain data stream will show an annual modulation. This property is fundamentally different from those of the SGWBs. In this Letter, we propose a new filtering method for the data vector based on the annual modulation phenomenon. We apply the resulted inverse variance filter to the LISA data challenge. The result shows that for the weaker SGWB signal, such as energy density $\Omega_{\rm astro}=5\times10^{-12}$, the filtering method can enhance the posterior distribution peak prominently. For the stronger signal, such as $\Omega_{\rm astro}=15\times10^{-12}$, the method can improve the Bayesian evidence from `substantial' to `strong' against null hypotheses. This method is model-independent and self-contained. It does not ask for other types of information besides the gravitational wave data.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Shanhao Zhu
Yiping Shu
Haibo Yuan
Jian-Ning Fu
Jian Gao
Jianghua Wu
Xiangtao He
Kai Liao
Guoliang Li
Xinzhong Er
Bin Hu
摘要： As a completely independent method, the measurement of time delay of strongly lensed quasars (TDSL) are crucial to resolve the Hubble tension. Extensive monitoring is required but so far limited to a small sample of strongly lensed quasars. Together with several partner institutes, Beijing Normal University is constructing a 1.93m reflector telescope at the Muztagh-Ata site in west China, which has the world class observing conditions. The telescope will be equipped with both a three-channel imager/photometer which covers $3500-11000$ Angstrom wavelength band, and a low-medium resolution ($\lambda/\delta\lambda=500/2000/7500$) spectrograph. In this paper, we investigate the capability of Muztagh-Ata 1.93m telescope in measuring time delays of strongly lensed quasars. We generate mock strongly lensed quasar systems and light curves with microlensing effects based on five known strongly lensed quasars, i.e., RX J1131-1231, HE 0435-1223, PG 1115+080, WFI 2033-4723 and SDSS 1206+4332. In particular, RX J1131-1231 is generated with lens modeling in this work. Due to lack of enough information, we simulate the other 4 systems with the public data without lens modeling. According to simulations, for RX J1131-like systems (wide variation in time delay between images) the TDSL measurement can be achieved with the precision about $\Delta t=0.5$ day with 4 seasons campaign length and 1 day cadence. This accuracy is comparable to the up-coming TDCOSMO project. And it would be better when the campaign length keeps longer and with high cadence. As a result, the capability of Muztagh-Ata 1.93m telescope allows it to join the network of TDSL observatories. It will enrich the database for strongly lensed quasar observations and make more precise measurements of time delays, especially considering the unique coordinate of the site.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jiming Chen
Shamik Ghosh
Hao Liu
Larissa Santos
Wenjuan Fang
Siyu Li
Yang Liu
Hong Li
Jiaxin Wang
Le Zhang
Bin Hu
Wen Zhao
摘要： Constructing a fast and efficient estimator for the B-mode power spectrum of cosmic microwave background (CMB) is of critical importance for CMB science. For a general CMB survey, the Quadratic Maximum Likelihood (QML) estimator for CMB polarization has been proved to be the optimal estimator with minimal uncertainties, but it is computationally very expensive. In this article, we propose two new QML methods for B-mode power spectrum estimation. We use the Smith-Zaldarriaga approach to prepare pure-B mode map, and E-mode recycling method to obtain a leakage free B-mode map. We then use the scalar QML estimator to analyze the scalar pure-B map (QML-SZ) or B-mode map (QML-TC). The QML-SZ and QML-TC estimators have similar error bars as the standard QML estimators but their computational cost is nearly one order of magnitude smaller. The basic idea is that one can construct the pure B-mode CMB map by using the E-B separation method proposed by Smith-Zaldarriaga (SZ) or the one considering the template cleaning (TC) technique, then apply QML estimator to these scalar fields. By simulating potential observations of space-based and ground-based detectors, we test the reliability of these estimators by comparing them with the corresponding results of the traditional QML estimator and the pure B-mode pseudo-Cl estimator.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： For the stochastic gravitational wave backgrounds (SGWBs) search centred at the milli-Hz band, the galactic foreground produced by white dwarf binaries (WDBs) within the Milky Way contaminates the extra-galactic signal severely. Because of the anisotropic distribution pattern of the WDBs and the motion of the spaceborne gravitational wave interferometer constellation, the time-domain data stream will show an annual modulation. This property is fundamentally different from those of the SGWBs. In this Letter, we propose a new filtering method for the data vector based on the annual modulation phenomenon. We apply the resulted inverse variance filter to the LISA data challenge. The result shows that for the weaker SGWB signal, such as energy density $\Omega_{\rm astro}=5\times10^{-12}$, the filtering method can enhance the posterior distribution peak prominently. For the stronger signal, such as $\Omega_{\rm astro}=15\times10^{-12}$, the method can improve the Bayesian evidence from `substantial' to `strong' against null hypotheses. This method is model-independent and self-contained. It does not ask for other types of information besides the gravitational wave data.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jiakang Han
Bin Hu
Shamik Ghosh
Siyu Li
Jiazheng Dou
Jacques Delabrouille
Jing Jin
Hong Li
Yang Liu
Mathieu Remazeilles
Wen Zhao
Pengjie Zhang
Zheng-Wei Li
Cong-Zhan Liu
Yong-jie Zhang
Chao-Lin Kuo
Xinmin Zhang
摘要： Cosmic microwave background radiation (CMB) observations are unavoidably contaminated by emission from various extra-galactic foregrounds, which must be removed to obtain reliable measurements of the cosmological signal. In this paper, we demonstrate CMB lensing reconstruction in AliCPT-1 after foreground removal, combine the two bands of AliCPT-1 (90 and 150~GHz) with Planck HFI bands (100, 143, 217 and 353~GHz) and with the WMAP-K band (23~GHz). In order to balance contamination by instrumental noise and foreground residual bias, we adopt the Needlet Internal Linear Combination (NILC) method to clean the E-map and the constrained Internal Linear Combination (cILC) method to clean the B-map. The latter utilizes additional constraints on average frequency scaling of the dust and synchrotron to remove foregrounds at the expense of somewhat noisier maps. Assuming 4 modules observing 1 season from simulation data, the resulting effective residual noise in E- and B-map are roughly $15~\mu{\rm K}\cdot{\rm arcmin}$ and $25~\mu{\rm K}\cdot{\rm arcmin}$, respectively. As a result, the CMB lensing reconstruction signal-to-noise ratio (SNR) from polarization data is about SNR$\,\approx\,$4.5. This lensing reconstruction capability is comparable to that of other stage-III small aperture millimeter CMB telescopes.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Gravitational waves (GWs) may be magnified or de-magnified due to lensing. This phenomenon will bias the distance estimation based on the matched filtering technique. Via the multi-sphere ray-tracing technique, we study the GW magnification effect and selection effect with particular attention to the stellar-mass binary black holes (BBHs). We find that, for the observed luminosity distance $\lesssim 3~\mathrm{Gpc}$, which is the aLIGO/Virgo observational horizon limit, the average magnification keeps as unity, namely unbiased estimation, with the relative distance uncertainty $\sigma(\hat{d})/\hat{d}\simeq0.5\%\sim1\%$. Beyond this observational horizon, the estimation bias can not be ignored, and with the scatters $\sigma(\hat{d})/\hat{d} = 1\%\sim 15\%$. Furthermore, we forecast these numbers for Einstein Telescope. We find that the average magnification keeps closely as unity for the observed luminosity distance $\lesssim 90~\mathrm{Gpc}$. The luminosity distance estimation error due to lensing for Einstein Telescope is about $\sigma(\hat{d})/\hat{d} \simeq 10\%$ for the luminosity distance $\gtrsim 25~\mathrm{Gpc}$. Unlike the aLIGO/Virgo case, this sizable error is not due to the selection effect. It purely comes from the unavoidably accumulated lensing magnification. Moreover, we investigated the effects of the orientation angle and the BH mass distribution models. We found that the results are strongly dependent on these two components.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： In prerecombination resolutions of the Hubble tension, such as early dark energy, new physics before recombination shifts the values of relevant cosmological parameters so that the models can fit with cosmic microwave background and baryon acoustic oscillations observations as well as $\Lambda$CDM does. In this paper, we clarify how the parameter shifts are related with $\delta H_0$, particularly we find the shift of primordial scalar spectral index scales as ${\delta n_s}\simeq 0.4{\delta H_0\over H_0}$ by performing the Monte Carlo Markov chain analysis with the Planck2018+BAO+Pantheon+R19+Keck Array/BICEP dataset. A novel point of our result is that if the current $H_0$ measured locally is correct, complete resolution of the Hubble tension seems to be pointing to a scale invariant Harrison-Zeldovich spectrum, i.e. $n_s= 1$ for $H_0\sim 73$km/s/Mpc.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We present a perturbative treatment of nonlinear galaxy clustering in the context of the cubic Galileon modified gravity model, in terms of 2nd order Lagrangian Perturbation theory and an extension of ellipsoidal collapse that includes Vainshtein screening. We numerically implement such prescriptions in the approximate PINOCCHIO code, and use it to generate realisations of the matter density field and halo catalogues with different prescriptions for ellipsoidal collapse. We investigate the impact of three different approximations in the computation of collapse times on the halo mass function, halo bias and matter power spectrum. In the halo mass function, both the modified gravity effect and the screening effect are significant in the high mass end, similar to what is found for other MG models. We perform a comparison with N-body simulations to assess the validity of our approach, and show that we can reproduce the same trend observed in simulations for all quantities considered. With a simple modification to the grouping algorithm of PINOCCHIO to take into account the gravity modification, and without the need to re-calibrate the algorithm, we show that we can reproduce the linear halo bias and the mildly-nonlinear matter power spectrum of simulations with good accuracy, especially for the implementation with Vainshtein screening. We stress that, while approximate, our method is orders of magnitude faster than a full N-body simulation, making it an optimal tool for the quick generation of large sets of halo catalogues for cosmological observables.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We present a python based parameter inference system for the gravitational wave (GW) measured in the millihertz band. This system includes the following features: the GW waveform originated from the massive black hole binaries (MBHB), the stationary instrumental gaussian noise, the higher-order harmonic modes, the full response function from the time delay interferometry (TDI) and the gaussian likelihood function with the dynamic nested parameter sampler. In particular, we highlight the role of higher-order modes. By including these modes, the luminosity distance estimation precision can be improved roughly by a factor of 50, compared with the case with only the leading order ($\ell=2,|m|=2$) mode. This is due to the response function of different harmonic modes on the inclination angle are different. Hence, it can help to break the distance-inclination degeneracy. Furthermore, we show the robustness of testing general relativity (GR) by using the higher-order harmonics. Our results show that the GW from MBHB can simultaneously constrain four of the higher harmonic amplitudes (deviation from GR) with a precision of $c_{21}=0.54^{+0.61}_{-0.82}$, $c_{32}=-0.65^{+0.22}_{-0.08}$, $c_{33}=0.56^{+0.60}_{-0.76}$ and $c_{44}=1.57^{+2.34}_{-1.90}$, respectively.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Shamik Ghosh
Yang Liu
Le Zhang
Siyu Li
Junzhou Zhang
Jiaxin Wang
Jiazheng Dou
Jiming Chen
Jacques Delabrouille
Mathieu Remazeilles
Chang Feng
Bin Hu
Zhi-Qi Huang
Hao Liu
Larissa Santos
Pengjie Zhang
Zhaoxuan Zhang
Wen Zhao
Hong Li
Xinmin Zhang
摘要： AliCPT is the first Chinese cosmic microwave background (CMB) experiment which will make the most precise measurements of the CMB polarization in the northern hemisphere. The key science goal for AliCPT is the detection of primordial gravitational waves (PGWs). It is well known that an epoch of cosmic inflation, in the very early universe, can produce PGWs, which leave an imprint on the CMB in form of odd parity $B$-mode polarization. In this work, we study the performance of the component separation and parameter estimation pipelines in context of constraining the value of the tensor-to-scalar ratio. Based on the simulated data for one observation season, we compare five different pipelines with different working principles. Three pipelines perform component separation at map or spectra level before estimating $r$ from the cleaned spectra, while the other two pipelines performs a global fit for both foreground parameters and $r$. We also test different methods to account for the effects of time stream filtering systematics. This work shows that our pipelines provide consistent and robust constraints on the tensor-to-scalar ratio and a consistent sensitivity $\sigma(r) \sim 0.02$. This showcases the potential of precise $B$-mode polarization measurement with AliCPT-1. AliCPT will provide a powerful opportunity to detect PGWs, which is complementary with various ground-based CMB experiments in the southern hemisphere.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： GW number count can be used as a novel tracer of the large scale structure (LSS) in the luminosity distance space (LDS), just like galaxies in the redshift space. It is possible to obtain the $D_L-D_A$ duality relation with clustering effect. However, several LSS induced errors will contaminate the GW luminosity distance measurement, such as the peculiar velocity dispersion error of the host galaxy as well as the foreground lensing magnification. The distance uncertainties induced from these effects will degrade the GW clustering from a spectroscopic-like data down to a photometric-like data. In this paper, we investigate how these LSS induced distance errors modify our cosmological parameter precision inferred from the LDS clustering. We consider two of the next generation GW observatories, namely the Big Bang Observatory (BBO) and the Einstein Telescope (ET). We forecast the parameter estimation errors on the angular diameter distance $D_A$, luminosity distance space Hubble parameter $H_L$ and structure growth rate $f_L\sigma_8$ with a Fisher matrix method. Generally speaking, the GW source clustering data can be used for cosmological studies below $D_L<5$ Gpc, while above this scale the lensing errors will increase significantly. We find that for BBO, it is possible to constrain the cosmological parameters with a relative error of $10^{-3}$ to $10^{-2}$ below $D_L<5$ Gpc. The velocity dispersion error is dominant in the low luminosity distance range, while the lensing magnification error is the bottleneck in the large luminosity distance range. To reduce the lensing error, we assumed a $50\%$ delensing efficiency. Even with this optimal assumption, the fractional error increased to $O(1)$ at luminosity distance $D_L=25$ Gpc. The results for ET are similar as those from BBO. Due to the GW source number in ET is less than that from BBO, the corresponding results also get a bit worse.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： A large number of galactic binary systems emit gravitational waves (GW) continuously with frequencies below $\sim$10 mHz. The LISA mission could identify the tens of thousands of binaries over years of observation and will be subject to the confusion noise around 1 mHz yielded by the unresolved sources. Beyond LISA, there are several missions have been proposed to observe GWs in the sub-mHz range where the galactic foreground is expected to be overwhelming the instrumental noises. In this study, we investigate the detectability of sub-mHz GW missions to detect the galactic double white dwarf (DWD) binaries and evaluate the confusion noise produced by the undistinguished DWDs. This confusion noise could also be viewed as a stochastic GW foreground and be effectively observed in the sub-mHz band. The parameter determinations for the modeled foreground are examined by employing different detector sensitivities and population models. By assuming the determined foregrounds could be subtracted from the data, we evaluate the residuals which are expected to have power spectral densities two orders of magnitude lower than the originals data.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jinyi Liu
Zeyang Sun
Jiakang Han
Julien Carron
Jacques Delabrouille
Siyu Li
Yang Liu
Jing Jin
Shamik Ghosh
Bin Yue
Pengjie Zhang
Chang Feng
Zhi-Qi Huang
Hao Liu
Yi-Wen Wu
Le Zhang
Zi-Rui Zhang
Wen Zhao
Bin Hu
Hong Li
摘要： AliCPT-1 is the first Chinese CMB experiment aiming for high precision
measurement of Cosmic Microwave Background B-mode polarization. The telescope,
currently under deployment in Tibet, will observe in two frequency bands
centered at 90 and 150 GHz. We forecast the CMB lensing reconstruction,
lensing-galaxy as well as lensing-CIB (Cosmic Infrared Background) cross
correlation signal-to-noise ratio (SNR) for AliCPT-1. We consider two stages
with different integrated observation time, namely "4 module*yr" (first stage)
and "48 module*yr" (final stage). For lensing reconstruction, we use three
different quadratic estimators, namely temperature-only, polarization-only and
minimum-variance estimators, using curved sky geometry. We take into account
the impact of inhomogeneous hit counts as well as of the mean-field bias due to
incomplete sky coverage. In the first stage, our results show that the 150 GHz
channel is able to measure the lensing signal at $15\sigma$ significance with
the minimum-variance estimator. In the final stage, the measurement
significance will increase to $31\sigma$. We also combine the two frequency
data in the harmonic domain to optimize the SNR. Our result show that the
coadding procedure can significantly reduce the reconstruction bias in the
multiple range l>800. Thanks to the high quality of the polarization data in
the final stage of AliCPT-1, the EB estimator will dominate the lensing
reconstruction in this stage. We also estimate the SNR of cross-correlations
between AliCPT-1 CMB lensing and other tracers of the large scale structure of
the universe. For its cross-correlation with DESI galaxies/quasars, we report
the cross-correlation SNR = 10-20 for the 4 redshift bins at 0.05
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The strong lensing gravitational wave (SLGW) is a promising transient phenomenon containing rich physics. However, the poor sky localization due to the long-wave nature of gravitational waves makes the identification of such events very challenging. We propose a new method based on the wave optics effect of the microlensing field embedded in SLGW data. The microlensing diffraction/interference fringes can produce frequency-dependent random fluctuations in the waveform. To pin down the microlensing induced stochastic features in the waveform, we utilize both the template-independent method, \texttt{cWB}, and the template-dependent method, \texttt{Bilby}, to reconstruct the waveform with and without microlensing imprints. The mismatching degree of these two waveforms can be treated as an indicator of SLGW events. We forecast the identification rate of this method with the third-generation gravitational wave observatory, such as Cosmic Explorer. Our result shows that this method can successfully identify about 2 (out of 180) SLGW events with strong enough microlensing effect per year. This method is entirely data-driven, which is immune to model priors, and can greatly avoid the false positive errors contaminated by the coincident unlensed events.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： The Hubble parameter is one of the central parameters in modern cosmology, which describes the present expansion rate of the universe. Their values inferred from the late-time observations are systematically higher than those from the early-time measurements by about $10\%$. To come to a robust conclusion, independent probes with accuracy at percent levels are crucial. Gravitational waves from compact binary coalescence events can be formulated into the standard siren approach to provide an independent Hubble parameter measurement. The future space-borne gravitational wave observatory network, such as the LISA-Taiji network, will be able to measure the gravitational wave signals in the Millihertz bands with unprecedented accuracy. By including several statistical and instrumental noises, we show that within 5 years operation time, the LISA-Taiji network is able to constrain the Hubble parameter within $1\%$ accuracy, and possibly beats the scatters down to $0.5\%$ or even better.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jiakang Han
Bin Hu
Shamik Ghosh
Siyu Li
Jiazheng Dou
Jacques Delabrouille
Jing Jin
Hong Li
Yang Liu
Mathieu Remazeilles
Wen Zhao
Pengjie Zhang
Zheng-Wei Li
Cong-Zhan Liu
Yong-jie Zhang
Chao-Lin Kuo
Xinmin Zhang
摘要： Cosmic microwave background radiation (CMB) observations are unavoidably contaminated by emission from various extra-galactic foregrounds, which must be removed to obtain reliable measurements of the cosmological signal. In this paper, we demonstrate CMB lensing reconstruction in AliCPT-1 after foreground removal, combine the two bands of AliCPT-1 (90 and 150~GHz) with Planck HFI bands (100, 143, 217 and 353~GHz) and with the WMAP-K band (23~GHz). In order to balance contamination by instrumental noise and foreground residual bias, we adopt the Needlet Internal Linear Combination (NILC) method to clean the E-map and the constrained Internal Linear Combination (cILC) method to clean the B-map. The latter utilizes additional constraints on average frequency scaling of the dust and synchrotron to remove foregrounds at the expense of somewhat noisier maps. Assuming 4 modules observing 1 season from simulation data, the resulting effective residual noise in E- and B-map are roughly $15~\mu{\rm K}\cdot{\rm arcmin}$ and $25~\mu{\rm K}\cdot{\rm arcmin}$, respectively. As a result, the CMB lensing reconstruction signal-to-noise ratio (SNR) from polarization data is about SNR$\,\approx\,$4.5. This lensing reconstruction capability is comparable to that of other stage-III small aperture millimeter CMB telescopes.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Thermo-optic (TO) phase shifters are very fundamental units in large-scale active silicon photonic integrated circuits (PICs). However, due to the limitation of microheater materials with a trade-off between heating efficiency and absorption loss, designs reported so far typically suffer from slow response time, high power consumption, low yields, and so on. Here, we demonstrate an energy-efficient, fast-response, and low-loss TO phase shifter by introducing hydrogen-doped indium oxide (IHO) films as microheater, and the optimized electron concentration with enhanced mobility endows the IHO high conductivity as well as high near-infrared (NIR) transparency, which allow it to directly contact the silicon waveguide without any insulating layer for efficient tuning and fast response. The TO phase shifter achieves a sub-microsecond response time (970 ns/980 ns) with a {\pi} phase shift power consumption of 9.6 mW. And the insertion loss introduced by the IHO microheater is ~ 0.5 dB. The proposed IHO-based microheaters with compatible processing technology illustrate the great potential of such material in the application of large-scale silicon PICs.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-09-27
摘要： By using the cubic spline interpolation method, we reconstruct the shape of the primordial scalar and tensor power spectra from the recently released Planck temperature and BICEP2 polarization cosmic microwave background data. We find that the vanishing scalar index running (dns/d ln k) model is strongly disfavored at more than 3σ confidence level on the k = 0.0002 Mpc−1 scale. Furthermore, the power-law parameterization gives a blue-tilt tensor spectrum, no matter using only the first 5 bandpowers nt = 1.20+0.56 (95%CL) or the full 9 bandpowers nt = 1.24+0.51 (95%CL) of−0.64 −0.58BICEP2 data sets. Unlike the large tensor-to-scalar ratio value (r 0.20) under the scale-invariant tensor spectrum assumption, our interpolation approach gives r0.002 < 0.060 (95%CL) by using the first 5 bandpowers of BICEP2 data. After comparing the results with/without BICEP2 data, we find that Planck temperature with small tensor amplitude signals and BICEP2 polarization data with large tensor amplitude signals dominate the tensor spectrum reconstruction on the large and small scales, respectively. Hence, the resulting blue tensor tilt actually reflects the tension between Planck and BICEP2 data.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-09-27
摘要： We update the cosmological parameter estimation for three non-vanilla models by a joint analysis of CCCP X-ray cluster, the newly released Planck CMB data as well as some external data sets, such as baryon acoustic oscillation measurements from the 6dFGS, SDSS DR7 and BOSS DR9 surveys, and Hubble Space Telescope H0 measurement. First of all, we nd that X-ray cluster data sets strongly favor a non-zero summed neutrino mass at more than 3 con dence level in these non-vanilla models. And then, we reveal some tensions between X-ray cluster and Planck data in some cosmological parameters. For the matter power spectrum amplitude 8, X-ray cluster data favor a lower value compared with Planck. Because P of the strong 8 m degeneracy, this tension could beyond 2 con dence level when the P summed neutrino mass m is allowed to vary. For the CMB lensing amplitude AL, the addition of X-ray cluster data results in a 3 deviation from the vanilla model. Furthermore, Planck+X-ray data prefer a large Hubble constant and phantom-like dark energy equation of state, which are in 2 tension with those from WMAP7+X-ray data. Finally, we nd that these tensions/descrepencies could be relaxed in some sense by adding a 9% systematic shift in the cluster mass functions.
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