We briefly introduce the disadvantages for Type Ia supernovae (SNe Ia) as standard candles to measure the Universe, and suggest Gamma-ray bursts (GRBs) can serve as a powerful tool for probing the properties of high redshift Universe. We use GRBs as distance indicators in constructing the Hubble diagram at redshifts beyond the current reach of SNe Ia observations. Since the progenitors of long GRBs are confirmed to be massive stars, they are deemed as an effective approach to study the cosmic star formation rate (SFR). A detailed representation of how to measure high-$z$ SFR using GRBs is presented. Moreover, first stars can form only in structures that are suitably dense, which can be parameterized by defining the minimum dark matter halo mass $M_{\rm min}$. $M_{\rm min}$ must play a crucial role in star formation. The association of long GRBs with the collapses of massive stars also indicates that the GRB data can be applied to constrain the minimum halo mass $M_{\rm min}$ and to investigate star formation in dark matter halos.
The Hubble parameter $H(z)$ is directly related to the expansion of our Universe. It can be used to study dark energy and constrain cosmology models. In this paper, we propose that $H(z)$ can be measured using fast radio bursts (FRBs) with redshift measurements. We use dispersion measures contributed by the intergalactic medium, which is related to $H(z)$, to measure Hubble parameter. We find that 500 mocked FRBs with dispersion measures and redshift information can accurately measure Hubble parameters using Monte Carlo simulation. The maximum deviation of $H(z)$ from standard $Λ$CDM model is …
The $Λ$CDM model successfully explains the majority of cosmological observations. However, the $Λ$CDM model is challenged by Hubble tension, a remarkable difference of Hubble constant $H_0$ between measurements from local probe and the prediction from Planck cosmic microwave background observations under $ Λ$CDM model. So one urgently needs new distance indicators to test the Hubble tension. Fast radio bursts (FRBs) are millisecond-duration pulses occurring at cosmological distances, which are attractive cosmological probes. However, there is a thorny problem that the dispersion measures (DMs)…
We examine the prospects of the high redshift Long Gamma Ray Bursts (LGRB) Hubble Diagram as a test of the basic cosmological principles. Analysis of the Hubble Diagram allows us to test several fundamental cosmological principles using the directly observed flux-distance-redshift relation. Modern LGRB data, together with the correlation between the spectral peak energy and the isotropic-equivalent radiated energy (the so-called Amati relation) can be used for construction of the Hubble Diagram at the model-independent level. We emphasise observational selection effects, which inevitably exist…
Until very recently we had as many theories to explain Fast Radio Bursts as we have observations of them. An explosion of data is coming, if not here already, and thus it is an opportune time to understand how we can use FRBs for cosmology. The HIRAX experiment, based mostly in South Africa, will be one such experiment, designed not only to observe large numbers of FRBs but also to localise them. In this short article we consider briefly, some ways in which HIRAX can change the landscape of FRB cosmology.
Fast radio bursts (FRBs) are very short and bright transients visible over extragalactic distances. The radio pulse undergoes dispersion caused by free electrons along the line of sight, most of which are associated with the large-scale structure (LSS). The total dispersion measure therefore increases with the line of sight and provides a distance estimate to the source. We present the first measurement of the Hubble constant using the dispersion measure -- redshift relation of FRBs with identified host counterpart and corresponding redshift information. A sample of nine currently available FR…
The simultaneous detection of gravitational waves and light from the binary neutron star merger GW170817 led to independent measurements of distance and redshift, providing a direct estimate of the Hubble constant $H_0$ that does not rely on a cosmic distance ladder nor assumes a specific cosmological model. By using gravitational waves as ''standard sirens'', this approach holds promise to arbitrate the existing tension between the $H_0$ value inferred from the cosmic microwave background and those obtained from local measurements. However, the known degeneracy in the gravitational-wave analy…
Gamma-ray bursts are the most energetic explosions in the Universe. They are detectable up to very high redshifts, therefore can be used to study the expansion rate of the Universe and to investigate the observational properties of dark energy, provided that empirical correlations between spectral and intensity properties are appropriately calibrated. We used the type Ia supernova luminosity distances to calibrate the correlation between the peak photon energy, $E_{p, i}$, and the isotropic equivalent radiated energy, $ E_{iso}$ in GRBs. With this correlation, we tested the reliability of appl…
Gamma-ray bursts are the most powerful explosions in the universe and are mainly placed at very large redshifts, up to $z\simeq 9$. In this short review, we first discuss gamma-ray burst classification and morphological properties. We then report the likely relations between gamma-ray bursts and other astronomical objects, such as black holes, supernovae, neutron stars, etc., discussing in detail gamma-ray burst progenitors. We classify long and short gamma-ray bursts, working out their timescales, and introduce the standard fireball model. Afterwards, we focus on direct applications of gamma-…
High-redshift star formation rate up to z~8.3 derived from gamma-ray bursts and influence of background cosmology
高红移恒星形成率（SFR）即使用现代方法也很难直接测量。长持续时间的伽马射线暴（GRB）由于其高亮度，可以在可见宇宙的边缘被探测到。长伽马射线暴的Eksar模型表明，它们可以追踪恒星形成的历史。因此，长伽马射线暴可能是测量高红移SFR的有用工具。观测表明，长伽马射线暴更倾向于在低金属含量的环境中形成。在不同的背景宇宙学模型（包括$Λ$ CDM、quintessence、quintessence with a time-varying equation of state和brane-world model）下，研究了追踪恒星形成历史和宇宙金属丰度演化的Swift伽玛暴的高红移SFR（z~8.3）。我们使用最新的Swift伽玛暴，包括两个最高的$z$伽玛暴，$z=6.7$的GRB 080913和$z=8.3$的GRB 090423。我们发现，在$z>4$的SFR表现出陡峭的衰减与$\sim -5.0$在$Λ$ CDM的斜率。在其他三个模型中，高红移SFR与$Λ$ CDM模型略有不同，也表现出陡峭的衰减。
The direction of the axis of the orbital motion of the merging binary neutron stars in the GW170817 event coincided with that of the apparent superluminal jet, which produced the short hard gamma ray burst (SHB) 170817A, if the local value of the Hubble constant is that provided by standard candle Type Ia supernovae, H_0=73.24 +/- 1.74 km/s Mpc. This value differs by 3 sigma from the cosmic value H_0=67.74 +/- 0.46 km/s Mpc obtained from the cosmic microwave background radiation by Planck assuming the standard Lambda-CDM cosmology. The measured superluminal motion of the jet also allows critic…
Gamma-ray bursts (GRBs) are widely proposed as an effective probe to trace the Hubble diagram of the Universe in high redshift range. However, the calibration of GRBs is not as easy as that of type-Ia supernovae (SNe Ia). Most calibrating methods at present make use one or some of the empirical luminosity correlations, e.g., Amati relation. One of the underlying assumptions of these calibrating methods is that the empirical correlation is universal over all redshifts. In this paper, we check to what extent this assumption holds. Assuming that SNe Ia exactly trace the Hubble diagram of the Univ…
Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, which emit up to $8.8\times10^{54}$ erg isotropic equivalent energy in the hard X-ray band. The high luminosity makes them detectable out to the largest distances yet explored in the Universe. GRBs, as bright beacons in the deep Universe, would be the ideal tool to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal enrichment history of the Universe. In this article, we review the luminosity correlations…
This article gives an overview of gamma-ray bursts (GRBs) and their relation to astroparticle physics and cosmology. GRBs are the most powerful explosions in the universe that occur roughly once per day and are characterized by flashes of gamma-rays typically lasting from a fraction of a second to thousands of seconds. Even after more than four decades since their discovery they still remain not fully understood. Two types of GRBs are observed: spectrally harder short duration bursts and softer long duration bursts. The long GRBs originate from the collapse of massive stars whereas the preferr…
Fast Radio Burst Cosmology: Hubble Tension and Dark Energy
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（南京大学现代天文与天体物理教育部重点实验室）；Department of Astronomy, University of Science and Technology of China（中国科学技术大学天文系）
The electromagnetic radiation that followed the neutron star merger event GW170817 revealed that gamma-ray burst afterglows from jets misaligned with our line of sight exhibit a light curve with slowly rising flux. The slope of the rising light curve depends sensitively on the angle of the observer with respect to the jet axis, which is likely to be perpendicular to the merger plane of the neutron star binary. Therefore, the afterglow emission can be used to constrain the inclination of the merging system. Here, we calculate the gamma-ray burst afterglow emission based on the realistic jet str…
The Cosmological Principle is the assumption that the universe is spatially homogeneous and isotropic in the large-scale average. In year 1998 the author, together with his two colleagues, has shown that the BATSE's short gamma-ray bursts are not distributed isotropically on the sky. This claim was then followed by other papers confirming both the existence of anisotropies in the angular distribution of bursts and the existence of huge Gpc structures in the spatial distribution. These observational facts are in contradiction with the Cosmological Principle, because the large scale averaging ha…
We use a recently proposed luminosity distance measure for relatively nearby active galactic nuclei (AGNs) to test the predicted expansion of the Universe in the R_h=ct and LCDM cosmologies. This comparative study is particularly relevant to the question of whether or not the Universe underwent a transition from decelerated to accelerated expansion, which is believed to have occurred---on the basis of Type Ia SN studies---within the redshift range (0 < z < 1.3) that will eventually be sampled by these objects. We find that the AGN Hubble Diagram constructed from currently available sources doe…
Recently, some theoretical models predicted that a small fraction of fast radio bursts (FRBs) could be associated with gravitational waves (GWs). In this work, we discuss the possibility of using GW/FRB association systems, if commonly detected in the future, as a complementary cosmic probe. We propose that upgraded standard sirens can be constructed from the joint measurements of luminosity distances $D_{L}$ derived from GWs and dispersion measures ${\rm DM_{IGM}}$ derived from FRBs (i.e., the combination $D_{L}\cdot{\rm DM_{IGM}}$). Moreover, unlike the traditional standard-siren approach (i…
The excessive dispersion measure (DM) of fast radio bursts (FRBs) has been proposed to be a powerful tool to study intergalactic medium (IGM) and to perform cosmography. One issue is that the fraction of baryons in the IGM, $f_{\rm IGM}$, is not properly constrained. Here we propose a method of estimating $f_{\rm IGM}$ using a putative sample of FRBs with the measurements of both DM and luminosity distance $d_{\rm L}$. The latter can be obtained if the FRB is associated with a distance indicator (e.g. a gamma-ray burst or a gravitational wave event), or the redshift $z$ of the FRB is measured …
We present deep Hubble Space Telescope near-infrared (NIR) observations of the magnetar SGR 1935+2154 from June 2021, approximately 6 years after the first HST observations, a year after the discovery of fast radio burst like emission from the source, and in a period of exceptional high frequency activity. Although not directly taken during a bursting period the counterpart is a factor of ~1.5 to 2.5 brighter than seen at previous epochs with F140W(AB) = $24.65\pm0.02$ mag. We do not detect significant variations of the NIR counterpart within the course of any one orbit (i.e. on minutes-hour t…
Five fast radio bursts (FRBs), including three apparently non-repeating ones FRB 180924, FRB 181112, and FRB 190523, and two repeaters, FRB 121102 and FRB 180916.J0158+65, have already been localized so far. We apply a method developed recently by us (Li et al. 2019) to these five localized FRBs to give a cosmology-insensitive estimate of the fraction of baryon mass in the IGM, $f_{\rm IGM}$. Using the measured dispersion measure (DM) and luminosity distance $d_{\rm L}$ data (inferred from the FRB redshifts and $d_{\rm L}$ of type Ia supernovae at the same redshifts) of the five FRBs, we const…
