分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: In this paper, we calibrate the Amati relation (the $E_{\rm p}$-${E}_{\rm
iso}$ correlation) of gamma-ray bursts (GRBs) in a cosmology-independent way.
By using Gaussian process to reconstruct the smoothed luminosity distance from
the Pantheon type Ia supernovae (SNe Ia) sample, we utilize the reconstructed
results to calibrate the $E_{\rm p}$-${E}_{\rm iso}$ correlation with the
Markov Chain Monte Carlo method and construct a Hubble diagram with the A220
GRB data, in which there are A118 GRB data with the higher qualities
appropriate for cosmological purposes. With 98 GRBs at $1.4
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: In this paper, we calibrate the Amati relation (the $E_{\rm p}$-${E}_{\rm
iso}$ correlation) of gamma-ray bursts (GRBs) in a cosmology-independent way.
By using Gaussian process to reconstruct the smoothed luminosity distance from
the Pantheon type Ia supernovae (SNe Ia) sample, we utilize the reconstructed
results to calibrate the $E_{\rm p}$-${E}_{\rm iso}$ correlation with the
Markov Chain Monte Carlo method and construct a Hubble diagram with the A220
GRB data, in which there are A118 GRB data with the higher qualities
appropriate for cosmological purposes. With 98 GRBs at $1.4
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: An improved Amati correlation was constructed in (ApJ 931 (2022) 50) by us recently. In this paper, we further study constraints on the $\Lambda$CDM and $w$CDM models from the gamma ray bursts (GRBs) standardized with the standard and improved Amati correlations, respectively. By using the Pantheon type Ia supernova sample to calibrate the latest A220 GRB data set, the GRB Hubble diagram is obtained model-independently. We find that at the high redshift region ($z>1.4$) the GRB distance modulus from the improved Amati correlation is larger apparently than that from the standard Amati one. The GRB data from the standard Amati correlation only give a lower bound limit on the present matter density parameter $\Omega_{\mathrm{m0}}$, while the GRBs from the improved Amati correlation constrain the $\Omega_{\mathrm{m0}}$ with the $68\%$ confidence level to be $0.308^{+0.066}_{-0.230}$ and $0.307^{+0.057}_{-0.290}$ in the $\Lambda$CDM and $w$CDM models, respectively, which are consistent very well with those given by other current popular observational data including BAO, CMB and so on. Once the $H(z)$ data are added in our analysis, the constraint on the Hubble constant $H_0$ can be achieved. We find that two different correlations provide slightly different $H_0$ results but the marginalized mean values seem to be close to that from the Planck 2018 CMB observations.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: We developed a GPU based single-pulse search pipeline (GSP) with candidate-archiving database. Largely based upon the infrastructure of Open source pulsar search and analysis toolkit (PRESTO), GSP implements GPU acceleration of the de-dispersion and integrates a candidate-archiving database. We applied GSP to the data streams from the commensal radio astronomy FAST survey (CRAFTS), which resulted in a quasi-real-time processing. The integrated candidate database facilitates synergistic usage of multiple machine-learning tools and thus improves efficient identification of radio pulsars such as rotating radio transients (RRATs) and Fast Radio Bursts (FRBs). We first tested GSP on pilot CRAFTS observations with the FAST Ultra-Wide Band (UWB) receiver. GSP detected all pulsars known from the the Parkes multibeam pulsar survey in the respective sky area covered by the FAST-UWB. GSP also discovered 13 new pulsars. We measured the computational efficiency of GSP to be ~120 times faster than the original PRESTO and ~60 times faster than a MPI-parallelized version of PRESTO.