Related papers: Hunting for the First Explosions at the High-Redsh…
We discuss the expected properties of the first stellar generations in the Universe. We find that it is possible to discern truly primordial populations from the next generation of stars by measuring the metallicity of high-z star forming…
The James Webb Space Telescope (JWST) is expected to revolutionize our understanding of the high-redshift Universe, and may be able to test the prediction that the first, chemically pristine (population III) stars formed with very high…
Supernovae are important probes of the properties of stars at high redshifts because they can be detected at early epochs and their masses can be inferred from their light curves. Direct detection of the first cosmic explosions in the…
Early observations with JWST have led to the discovery of an unexpected large density (stellar mass density $\rho_*\approx 10^{6}\,M_{\odot}\,Mpc^{-3}$) of massive galaxies (stellar masses $M_*\geq 10^{10.5}M_{\odot}$) at extremely high…
The so-called `impossibly early galaxy' problem, first identified via the Hubble Space Telescope's observation of galaxies at redshifts z > 10, appears to have been exacerbated by the more recent James Webb Space Telescope (JWST) discovery…
From the onset of observations of JWST we have discovered unexpectedly luminous galaxies at redshifts $z>10$ and as high as $z=14$. With their discovery, the question immediately followed as to where their progenitors are, since such…
Pair-instability supernovae (PISNe) are explosions of very massive stars that may have played a critical role in the chemical evolution and reionization of the early Universe. In order to quantify their roles, it is required to know the…
Several bright and massive galaxy candidates at high redshifts have been recently observed by the James Webb Space Telescope. Such early massive galaxies seem difficult to reconcile with standard $\Lambda$ Cold Dark Matter model…
Massive Population III stars from 140 - 260 solar masses ended their lives as pair-instability supernovae (PISNe), the most energetic thermonuclear explosions in the universe. Detection of these explosions could directly constrain the…
Massive stars at cosmological distances can be individually detected during transient microlensing events, when gravitational lensing magnifications may exceed ~1000. Nine such sources were identified in JWST NIRCam imaging of a single…
Searches for very-high-redshift galaxies over the past decade have yielded a large sample of more than 6,000 galaxies existing just 900-2,000 million years (Myr) after the Big Bang (redshifts 6 > z > 3; ref. 1). The Hubble Ultra Deep Field…
We present a comprehensive search and analysis of high-redshift galaxies in a suite of nine public JWST extragalactic fields taken in Cycle 1, covering a total effective search area of $\sim358{\rm arcmin^2}$. Through conservative…
We designed customized Lyman-break color selection techniques to identify galaxy candidates in the redshift ranges $15 \leq z \leq 20$ and $20 \leq z \leq 28$. The selection was performed on the ASTRODEEP-JWST multi-band catalogs of the…
Population III supernovae have been of growing interest of late for their potential to directly probe the properties of the first stars, particularly the most energetic events that are visible near the edge of the observable universe. But…
The first population III stars are predicted to form in minihalos at a redshift of approximately 10-30. The James Webb Space Telescope (JWST), tentatively scheduled for launch in 2018, will probably be able to detect some of the first…
With JWST, new opportunities to study the evolution of galaxies in the early Universe are emerging. Spitzer constraints on rest-optical properties of $z\gtrsim7$ galaxies demonstrated the power of using galaxy stellar masses and star…
The emergence of the first, so-called Population III (Pop III), stars shaped early cosmic history in ways that crucially depends on their initial mass function (IMF). However, because of the absence of direct observational constraints, the…
The James Webb Space Telescope (JWST) revealed a large population of active galactic nuclei (AGN) with redshifts greater than five. We show that if they emit ultrahigh-energy protons with energies up to $\lesssim 10^{19}$ eV, the cosmogenic…
The James Webb Space Telescope (JWST) has opened up a new window to study highly reddened explosive transients. We present results from late-time (1421 days post-explosion) JWST follow-up spectroscopic observations with NIRSpec and MIRI LRS…
Pair-instability supernovae (PISNe) have long been predicted to be the final fates of near-zero-metallicity very massive stars ($Z < Z_\odot/3$, $\mathrm{M}_\mathrm{ZAMS} \gtrsim 140 \mathrm{M}_\odot$). However, no definite PISN has been…