Browsing by Author "Zhu, Shuairu"

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    Discovery of Local Analogs to JWST's Little Red Dots
    (2024) Lin, Ruqiu; Zheng, Zhen-Ya; Jiang, Chunyan; Yuan, Fang-Ting; Ho, Luis C.; Wang, Junxian; Jiang, Linhua; Rhoads, James E.; Malhotra, Sangeeta; Barrientos, Luis Felipe; Wold, Isak; Infante Lira, Leopoldo; Zhu, Shuairu; Ji, Xiang; Fu, Xiaodan
    Recently, the James Webb Space Telescope (JWST) has revealed a new class of high redshift (high- z , z > 4) compact galaxies which are red in the rest-frame optical and blue in the rest-frame UV as V-shaped spectral energy distributions (SEDs), referred to as “Little Red Dots” (LRDs). It is very likely that LRDs host obscured broad-line active galactic nuclei (AGNs). In the meanwhile, Green pea galaxies (GPs), which are compact dwarf galaxies at low redshift, share various similar properties with high redshift star-forming galaxies. Here we aim to find the connection between the LRDs and GPs hosting broad-line AGNs (BLGPs). With a sample of 19 BLGPs obtained from our previous work, we further identify 7 GPs with V-shaped rest-frame UV-to-optical SEDs that are likely local analogs to LRDs. These V-shaped BLGPs exhibit faint UV absolute magnitudes and sub-Eddington rates similar to those of LRDs. Three of them occupy a similar region as LRDs in the BPT diagram, suggesting they have similar ionization conditions and gas-phase metallicities to LRDs. These similarities suggest that V-shaped BLGPs can be taken as local analogs of high-redshift LRDs. In addition, most (16/19) BLGPs, including 6 V-shaped BLGPs, host over-massive black holes above the local M BH- M∗ relation, making it the first sample of galaxies hosting over-massive black holes at z < 0.4. These findings will help us learn more about the formation and co-evolution of early galaxies and black holes.
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    The Hubble Deep Hydrogen Alpha (HDHα) Project. I. Catalog of Emission-line Galaxies
    (2024) Zhu, Shuairu; Zheng, Zhen-Ya; Rhoads, James; Wang, Junxian; Jiang, Linhua; Jiang, Chunyan; Yuan, Fang-Ting; Rahna, P. T.; Hu, Weida; Lin, Ruqiu; Shan, Huanyuan; Xu, Chun; Infante, Leopoldo; Barrientos, L. Felipe; Zheng, Xianzhong; Fang, Guanwen; Liang, Zhixiong
    We present the first results of the Hubble Deep Hydrogen Alpha (HDHα) project, which analyzes the space-borne deep Hα narrowband imaging data in the GOODS-S region. The HDHα data comprises 72 orbits' images taken with the Hubble Space Telescope (HST) Advanced Camera for Surveys/Wide Field Channel F658N filter. The exposure time varies across a total area of ∼76.1 arcmin2, adding up to a total exposure time of 195.7 ks, among which 68.8 ks are spent in the deepest region. These images are aligned, reprojected, and combined to have the same pixel grid as the Hubble Legacy Fields. The scientific goals of the HDHα include establishing a sample of emission-line galaxies (ELGs) including [O III] emitters at z ∼ 0.3, [O II] emitters at z ∼ 0.8, and Lyα emitters (LAEs) at z ∼ 4.4, studying the line morphology of ELGs with high resolution imaging data, and statistically analyzing the line luminosity functions and line equivalent-width distributions of ELGs selected with HST. Furthermore, the HDHα project enhances the legacy value of the GOODS-S field by contributing the first HST-based narrowband image to the existing data sets, which includes the HST broadband data and other ancillary data from X-ray to radio taken by other facilities. In this paper, we describe the data reduction process of the HDHα, select ELGs based on HST's F658N and broadband data, validate the redshifts of the selected candidates by crossmatching with the public spectroscopic catalogs in the GOODS-S, and present a final catalog of the confirmed [O III] emitters at z ∼ 0.3, [O II] emitters at z ∼ 0.8, and LAEs at z ∼ 4.4....