本帖最後由 mca 於 2017-7-8 21:29 編輯
NRAO 在 2017.06.27 發佈的天文新聞:
研究人員利用美國甚長基線陣列 (VLBA),經過多年觀測的比較後,首次在射電波段 “看” 到特大質量雙黑洞 (supermassive black hole binary) 互繞時產生的電磁波。VLBA 由 10 台分佈在美國各地的射電望遠鏡組成,協同工作時相當於一台超强分辨率的射電望遠鏡。
這兩個特大質量黑洞位於英仙座一個 7.5 億光年外,編號爲 0402+379 的射電星系中央,雙黑洞彼此相距僅 24 光年,總質量達到太陽的 150 億倍,互繞一周需 3 萬年。
黑洞是引力強到連光也無法逃逸的天體,無法真正意義上被 “看” 到,但周圍物質被吸入黑洞時會釋放强烈的電磁波,暴露出黑洞的所在。
包括我們銀河系在內,絕大多數星系中央都有一個特大質量黑洞,其質量為太陽的幾百萬到數十億倍。研究人員認爲,這個雙黑洞系統是兩個星系併合而成的,預計它們最終會融合成爲單個黑洞,融合時爆發的引力波 (gravitational wave) 會波及整個宇宙。
相關論文發表在美國《天體物理學雜誌》上。研究人員説,由於星系併合是常見現象,這種雙黑洞系統應廣泛存在,他們接下來將尋找更多類似天體。
原論文概要
Constraining the Orbit of the Supermassive Black Hole Binary 0402+379
K. Bansal1, G. B. Taylor1,2, A. B. Peck3,4, R. T. Zavala5, and R. W. Romani6
Published 2017 June 27 • © 2017. The American Astronomical Society. All rights reserved.
The Astrophysical Journal, Volume 843, Number 1
Abstract
The radio galaxy 0402+379 is believed to host a supermassive black hole binary (SMBHB). The two compact-core sources are separated by a projected distance of 7.3 pc, making it the most (spatially) compact resolved SMBHB known. We present new multi-frequency VLBI observations of 0402+379 at 5, 8, 15, and 22 GHz and combine them with previous observations spanning 12 years. A strong frequency-dependent core shift is evident, which we use to infer magnetic fields near the jet base. After correcting for these shifts we detect significant relative motion of the two cores at β = v/c = 0.0054±0.0003 at PA = -34.4 deg. With some assumptions about the orbit, we use this measurement to constrain the orbital period p = 30,000 yr and SMBHB mass M = 15 billion solar mass. While additional observations are needed to confirm this motion and obtain a precise orbit, this is apparently the first black hole system resolved as a visual binary.
星系 0402+379 的射電圖,C1 和 C2 是在星系中心的兩個特大質量黑洞
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