Browsing by Author "Yang, Jinyi"

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    Discovery and characterization of 25 new quasars at 4.6 < z < 6.9 from wide-field multiband surveys
    (2025) Belladitta, Silvia; Bañados, Eduardo; Xie, Zhang-Liang; Decarli, Roberto; Onorato, Silvia; Yang, Jinyi; Bischetti, Manuela; Onoue, Masafusa; Loiacono, Federica; Martínez Ramirez, Laura Natalia; Mazzucchelli, Chiara; Davies, Frederick B.; Wolf, Julien; Schindler, Jan-Torge; Fan, Xiaohui; Wang, Feige; Walter, Fabian; Mkrtchyan, Tatevik; Stern, Daniel; Farina, Emanuele P.; Venemans, Bram P.
    Luminous quasars at provide key insights into the early Universe. Their rarity necessitates wide-field multi-band surveys to efficiently separate them from the main astrophysical contaminants (i.e., ultracool dwarfs). To expand the sample of high- quasars, we conducted targeted selections using optical, infrared, and radio surveys, complemented by literature-based quasar candidate catalogs. In this paper, we report the discovery of \nqsos\ new quasars at (six at ), with between 25.4 and 27.0. We also present new spectra of six quasars we selected, but whose independent discovery has already been published in the literature. Three of the newly discovered quasars are strong radio emitters (L10erg s Hz). Among them, one source at exhibits typical blazar-like properties, including a flat radio spectrum, radio-loudness 1000, and multi-frequency variability. It is also detected by SRG/eROSITA X-ray telescope (ferg s cm). In addition, for seven quasars we present near-infrared spectroscopy and estimate the central black hole mass from their C and Mg broad emission this http URL masses (log[M]) and Eddington ratios () are consistent with other quasars reported in the literature. A quasar exhibits a velocity difference of approximately km s between the C and Mg emission lines, making it one of the most extreme C outflows currently known. Additionally, the sample includes three high-ionization broad absorption line quasars. One of these quasars shows potential evidence of an extremely fast outflow feature, reaching km s.
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    The Identification of a Dusty Multiarm Spiral Galaxy at z =3.06 with JWST and ALMA
    (2023) Wu, Yunjing; Cai, Zheng; Sun, Fengwu; Bian, Fuyan; Lin, Xiaojing; Li, Zihao; Li, Mingyu; Bauer, Franz E.; Egami, Eiichi; Fan, Xiaohui; Gonzalez-Lopez, Jorge; Li, Jianan; Wang, Feige; Yang, Jinyi; Zhang, Shiwu; Zou, Siwei
    Spiral arms serve crucial purposes in star formation and galaxy evolution. In this paper, we report the identification of "A2744-DSG-z3," a dusty, multiarm spiral galaxy at z = 3.059 using the James Webb Space Telescope (JWST) NIRISS imaging and grism spectroscopy. A2744-DSG-z3 was discovered as a gravitationally lensed submillimeter galaxy with the Atacama Large Millimeter/submillimeter Array (ALMA). This is the most distant stellar spiral structure seen thus far, consistent with cosmological simulations that suggest z approximate to 3 as the epoch when spirals emerge. Thanks to the gravitational lensing and excellent spatial resolution of JWST, the spiral arms are resolved with a spatial resolution of approximate to 290 pc. Based on spectral energy distribution fitting, the spiral galaxy has a delensed star formation rate of 85 +/- 30 M (circle dot) yr(-1), and a stellar mass of approximate to 10(10.6) M (circle dot), indicating that A2744-DSG-z3 is a main-sequence galaxy. After fitting the spiral arms, we find a stellar effective radius (R (e,star)) of 5.0 +/- 1.5 kpc. Combining with ALMA measurements, we find that the effective radii ratio between dust and stars is approximate to 0.4, similar to those of massive star-forming galaxies (SFGs) at z similar to 2, indicating a compact dusty core in A2744-DSG-z3. Moreover, this galaxy appears to be living in a group environment: including A2744-DSG-z3, at least three galaxies at z = 3.05-3.06 are spectroscopically confirmed by JWST/NIRISS and ALMA, residing within a lensing-corrected projected scale of approximate to 70 kpc. This, along with the asymmetric brightness profile, further suggests that the spiral arms may be triggered by minor-merger events at z greater than or similar to 3.