Orphan GRB afterglow searches with the Pan-STARRS1 COSMOS survey

Gravitationally Lensed Orphan Afterglows of Gamma-Ray Bursts

The cosmological nature of gamma-ray bursts (GRBs) implies that a small portion of them could be gravitationally lensed by foreground objects during their propagation. The gravitational lensing effect on the GRB prompt emission and on-axis afterglows has been discussed, and some candidates have been found in the literature. In this work, considering the high detection rate of GRB orphan afterglows in future wide-field survey era, we investigate the gravitationally lensed orphan afterglows in view of three lens models, i.e., the point-mass model, the singular isothermal sphere model, and the Ch…

Pan-STARRS1 variability of XMM-COSMOS AGN. II. Physical correlations and power spectrum analysis

[Abbreviated] We search for scaling relations between the fundamental AGN parameters and rest-frame UV/optical variability properties for a sample of $\sim$90 X-ray selected AGNs covering a wide redshift range from the XMM-COSMOS survey, with optical light curves in four bands provided by the Pan-STARRS1 (PS1) Medium Deep Field 04 survey. To estimate the variability amplitude we utilize the normalized excess variance ($σ_{\mathrm{rms}}^{2}$) and probe variability on rest-frame timescales of several months and years by calculating $σ_{\mathrm{rms}}^{2}$ from different parts of our light curves.…

The Foundation Supernova Survey: Motivation, Design, Implementation, and First Data Release

The Foundation Supernova Survey aims to provide a large, high-fidelity, homogeneous, and precisely-calibrated low-redshift Type Ia supernova (SN Ia) sample for cosmology. The calibration of the current low-redshift SN sample is the largest component of systematic uncertainties for SN cosmology, and new data are necessary to make progress. We present the motivation, survey design, observation strategy, implementation, and first results for the Foundation Supernova Survey. We are using the Pan-STARRS telescope to obtain photometry for up to 800 SNe Ia at z < 0.1. This strategy has several unique…

Discovery of a Cosmological, Relativistic Outburst via its Rapidly Fading Optical Emission

We report the discovery by the Palomar Transient Factory (PTF) of the transient source PTF11agg, which is distinguished by three primary characteristics: (1) bright, rapidly fading optical transient emission; (2) a faint, blue quiescent optical counterpart; and (3) an associated year-long, scintillating radio transient. We argue that these observed properties are inconsistent with any known class of Galactic transients, and instead suggest a cosmological origin. The detection of incoherent radio emission at such distances implies a large emitting region, from which we infer the presence of rel…

追踪超大质量黑洞的崛起：利用COSMOS-Web及其他巡天项目对z>6处的暗弱无遮蔽类星体进行全色搜索

Tracing the rise of supermassive black holes: A panchromatic search for faint, unobscured quasars at z > 6 with COSMOS-Web and other surveys

本研究利用JWST驱动的多波段巡天数据，通过两阶段搜索策略识别出64个红移6-8的暗弱类星体候选体，发现其承载的超大质量黑洞质量相对宿主星系偏高，且蒙特卡洛分析支持直接坍缩的大质量种子是其演化途径，为研究早期宇宙天体提供了关键样本。