相关论文: The optimal redshift for detecting ionized bubbles…
We forecast the sensitivity with which the Murchison Widefield Array (MWA) can measure the 21 cm power spectrum of cosmic hydrogen, using radiative transfer simulations to model reionization and the 21 cm signal. The MWA is sensitive to…
We are constructing a program to estimate the redshifts for GRBs from the original Swift light curves and spectra, aiming to get redshifts for the Swift bursts \textit{without} spectroscopic or photometric redshifts. We derive the…
The high-redshift 21 cm signal from the Epoch of Reionization (EoR) is a promising observational probe of the early universe. Current- and next-generation radio interferometers such as the Hydrogen Epoch of Reionization Array (HERA) and…
The clustering pattern in high redshift HI maps is expected to be anisotropic due to two distinct reasons, the Alcock-Paczynski effect and the peculiar velocities, both of which are sensitive to the cosmological parameters. The signal is…
I describe the principle of using the 1.6um H- spectral feature as a photometric redshift indicator and demonstrate that the technique holds promise by successfully recovering the redshifts of a small sample of z=0-1 galaxies using only…
We study the observability of the reionization epoch through the 21 cm hyperfine transition of neutral hydrogen. We use a high-resolution cosmological simulation (including hydrodynamics) together with a fast radiative transfer algorithm to…
We discuss the effect of dispersion delay due to intervening ionized media in the radio emission of gamma-ray bursts (GRBs). For high redshift GRBs ($z \ga 3$), the ionized intergalactic medium (IGM) should be the dominant source of…
We study quasar proximity zones in the redshift range $5.77 \leq z \leq 6.54$ by homogeneously analyzing $34$ medium resolution spectra, encompassing both archival and newly obtained data, and exploiting recently updated systemic redshift…
Gamma-ray bursts (GRBs) are intense, short-lived bursts of gamma-ray radiation observed up to a high redshift ($z \sim 10$) due to their luminosities. Thus, they can serve as cosmological tools to probe the early Universe. However, we need…
Observations of the 21-centimetre line of atomic hydrogen in the early Universe directly probe the history of the reionization of the gas between galaxies. The observations are challenging, though, because of the low expected signal…
With improving telescopes, it may now be possible to observe the Epoch of Reionization in multiple ways. We examine two of these observables - the excess light in the near-infrared background that may be due to high redshift stars and…
Deep surveys have recently discovered galaxies at the tail end of the epoch of reionization. In the near future, these discoveries will be complemented by a new generation of low-frequency radio observatories that will map the distribution…
Future detection of high-redshift gamma-ray bursts (GRBs) will be an important tool for studying the early Universe. Fast and accurate redshift estimation for detected GRBs is key for encouraging rapid follow-up observations by ground- and…
We investigate the radio afterglows of gamma-ray bursts (GRBs) and hypernovae (HNe) at high redshifts and quantify their detectability, as well as their potential usefulness for 21 cm absorption line studies of the intergalactic medium…
Infrared and radio observations of the Epoch of Reionization promise to revolutionize our understanding of the cosmic dawn, and major efforts with the JWST, MWA and HERA are underway. While measurements of the ionizing sources with infrared…
We show that the cosmic star formation rate per comoving volume should exhibit a distinct drop around the reionization redshift, when the HII regions in the intergalactic medium around individual ionizing sources first overlapped. The drop…
We present results from our search for HI 21-cm and OH 18-cm absorption at z~1-1.4 towards red quasars showing strong MgII absorption using uGMRT. The quasars J1501+1822 and J1521+5508 show multiple strong associated MgII absorption at…
Detection of the global redshifted 21-cm signal is an excellent means of deciphering the physical processes during the Dark Ages and subsequent Epoch of Reionization (EoR). However, detection of this faint monopole is challenging due to…
It has recently been suggested that the power spectrum of redshifted 21cm fluctuations could be used to measure the scale of baryonic acoustic oscillations (BAOs) during the reionisation era. The resulting measurements are potentially as…
We propose observations of the molecular gas distribution during the era of reionization. At $z \sim $ 6 to 8, $^{12}$CO$(J=1-0)$ line intensity results in a mean brightness temperature of about 0.5 $\mu$K with rms fluctuations of 0.1…