Pair-instability supernovae (PISNe) are the ultimate cosmic lighthouses, capable of being observed at z<25 and revealing the properties of primordial stars at cosmic dawn. But it is now understood that the spectra and light curves of these events evolved with redshift as the universe became polluted with heavy elements because chemically enriched stars in this mass range typically lose most of their hydrogen envelopes and explode as bare helium cores. The light curves of such transients can be considerably dimmer in the near infrared (NIR) today than those of primordial PISNe of equal energy and progenitor mass. Here, we calculate detection rates for PISNe whose progenitors lost their outer layers to either line-driven winds or rotation at z<10, their detection limit in redshift for the James Webb Space Telescope (JWST). We find that JWST may be able to detect only Pop II (metal-poor) PISNe over the redshift range of z<4, but not their Pop III (metal-free) counterparts.
This is the third sequel in a series discussing the discovery of various types of extragalactic transients with the {\it James Webb Space Telescope} in a narrow-field ($\sim 0.1$ deg$^2$), moderately deep ($m_{AB} \sim 27$ mag) survey. In this part we focus on the detectability and observational characteristics of Direct Collapse Black Holes (DCBH) and Tidal Disruption Events (TDE) around them. We use existing models for DCBH accretion luminosities and spectra as well as for TDE light curves, and find that accreting DCBH seeds may be bright enough for detection up to $z \sim 7$ with JWST NIRCa…
Future time-domain surveys for transient events in the near- and mid-infrared bands will significantly extend our understanding about the physics of the early Universe. In this paper we study the implications of a deep (~27 mag), long-term (~3 years), observationally inexpensive survey with the James Webb Space Telescope (JWST) within its Continuous Viewing Zone, aimed at discovering luminous supernovae beyond z~2 redshift. We explore the possibilities for detecting Superluminous Supernovae (SLSNe) as well as Type Ia supernovae at such high redshifts and estimate their expected numbers within …
A dust-free hierarchically nested supermassive-star model for James Webb Space Telescope Little Red Dots
Universitat Politècnica de València（瓦伦西亚理工大学）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）；Kavli Institute for Astronomy and Astrophysics at Peking University（北京大学科维理天文与天体物理研究所）
James Webb Space Telescope Observations of the Nearby and Precisely-Localized FRB 20250316A: A Potential Near-IR Counterpart and Implications for the Progenitors of Fast Radio Bursts
We present the $NuSTAR$ extragalactic survey of the $James$ $Webb$ $Space$ $Telescope$ ($JWST$) North Ecliptic Pole (NEP) Time-Domain Field. The survey covers a $\sim$0.16 deg$^2$ area with a total exposure of 681 ks acquired in a total of nine observations from three epochs. The survey sensitivities at 20% of the area are 2.39, 1.14, 2.76, 1.52, and 5.20 $\times$ 10$^{-14}$ erg cm$^{-2}$ s$^{-1}$ in the 3-24, 3-8, 8-24, 8-16, and 16-24 keV bands, respectively. The NEP survey is one of the most sensitive extragalactic surveys with $NuSTAR$ so far. A total of 33 sources were detected above 95% …
Cosmic rays (CRs) at sub-TeV energies play a fundamental role in the chemical and dynamical evolution of molecular clouds, as they control the ionisation, dissociation, and excitation of H$_{2}$. Their characterisation is important both for the interpretation of observations and for the development of theoretical models. The methods used so far for estimating the CR ionisation rate ($ζ$) in molecular clouds have several limitations due to uncertainties in the adopted chemical networks. We refine and extend the method proposed by Bialy (2020) to estimate $ζ$ by observing rovibrational transitio…
Direct Detection of Dark Photon Dark Matter with the James Webb Space Telescope
Tsinghua University（清华大学）；Peking University（北京大学）；Korea Advanced Institute of Science and Technology (KAIST)（韩国科学技术院）；Massachusetts Institute of Technology（麻省理工学院）
High-Redshift Type Ia Supernovae Exhibit Enhanced Calcium Abundances
Texas A&M Institute of Data Science, Texas A&M University（德克萨斯农工大学数据科学研究所）；Department of Electrical and Computer Engineering, Texas A&M University（德克萨斯农工大学电气与计算机工程系）；George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy, Texas A. & M. University, Department of Physics and Astronomy（德克萨斯农工大学乔治·P和辛西娅·伍兹基础物理与天文学研究所，物理与天文系）
We review the theoretical background and the observational searches made for surviving companions of Type Ia supernovae (SNe Ia). Theory comprises the characteristics of the stellar binary companions of the exploding white dwarfs at the time of the supernova outburst and the expected effects on them of the explosion, as well as their subsequent evolution. That includes space velocities, rotation, luminosities (with discussion of possible mechanisms producing very faint companions) . We then present the searches already made in the Galactic remnants of Type Ia supernovae and we assess the resul…
