宇宙で活動する超巨大ブラックホールの過去最大のマップを発表(Astronomers Unveil Largest-Ever Map of Universe’s Active Supermassive Black Holes)

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2024-03-18 ニューヨーク大学 (NYU)

新しいマップが、銀河の中心にある活動的な超大質量ブラックホールであるクェーサーの位置を記録し、宇宙史上最大の領域をカバーしている。このマップには約1.3百万個のクェーサーの位置と時間が記録されており、最も遠いものは宇宙が15億歳の時点で輝いていた。ニューヨーク市のフラットアイアン研究所のデイヴィッド・ホッグとスペインのドノスティア国際物理センターのケイト・ストーリー=フィッシャーが率いた研究チームが、ガイア宇宙望遠鏡のデータを使用してこのマップを作成した。

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Quaia、Gaia-unWISEクエーサーカタログ: 全天分光クェーサー・サンプル Quaia, the Gaia-unWISE Quasar Catalog: An All-sky Spectroscopic Quasar Sample

Kate Storey-Fisher, David W. Hogg, Hans-Walter Rix, Anna-Christina Eilers, Giulio Fabbian, Michael R. Blanton, and David Alonso
The Astrophysical Journal  Published:2024 March 18
DOI:10.3847/1538-4357/ad1328

宇宙で活動する超巨大ブラックホールの過去最大のマップを発表(Astronomers Unveil Largest-Ever Map of Universe’s Active Supermassive Black Holes)

Abstract

We present a new, all-sky quasar catalog, Quaia, that samples the largest comoving volume of any existing spectroscopic quasar sample. The catalog draws on the 6,649,162 quasar candidates identified by the Gaia mission that have redshift estimates from the space observatory’s low-resolution blue photometer/red photometer spectra. This initial sample is highly homogeneous and complete, but has low purity, and 18% of even the bright (G < 20.0) confirmed quasars have discrepant redshift estimates (∣Δz/(1 + z)∣ > 0.2) compared to those from the Sloan Digital Sky Survey (SDSS). In this work, we combine the Gaia candidates with unWISE infrared data (based on the Wide-field Infrared Survey Explorer survey) to construct a catalog useful for cosmological and astrophysical quasar studies. We apply cuts based on proper motions and colors, reducing the number of contaminants by approximately four times. We improve the redshifts by training a k-Nearest Neighbor model on SDSS redshifts, and achieve estimates on the G < 20.0 sample with only 6% (10%) catastrophic errors with ∣Δz/(1 + z)∣ > 0.2 (0.1), a reduction of approximately three times (approximately two times) compared to the Gaia redshifts. The final catalog has 1,295,502 quasars with G < 20.5, and 755,850 candidates in an even cleaner G < 20.0 sample, with accompanying rigorous selection function models. We compare Quaia to existing quasar catalogs, showing that its large effective volume makes it a highly competitive sample for cosmological large-scale structure analyses. The catalog is publicly available at 10.5281/zenodo.10403370.

1701物理及び化学
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