编辑“︁GW151226”︁

{{NoteTA
|G1=Physics
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{{infobox
| class       = vcard
| style       =
| titleclass  = fn org
| title       = GW151226
| image       = [[file:GW151226.png|300px]]
| caption     = LIGO的兩個探測器所得到的GW151226信號
| header1 = {{Infobox | decat = yes | child = yes
    | title =
    | label1= 說明
    | data1 = 第二次直接探測到引力波
    | label2= 事件類型
    | data2 = 引力波
   }}
| header2 = {{Infobox | decat = yes | child = yes
    | title = 探測時間
    | label1= 日期
    | data1 = 2015年12月26日
    | label2= 時間
    | data2 =  03:38:53.648 [[UTC]]
    | label3= 信號持續時間
    | data3 = 1 秒
    | label4= 探測器
    | data4 = [[LIGO]]
   }}
 | header3 = {{Infobox | decat = yes | child = yes
    | title = 物理性質
    | label1= 總能量輸出
    | data1 = ~ 1 [[太陽質量|{{solar mass}}]] × c<sup>2</sup> （通過引力波）
    | label2= 信號頻率
    | data2 = 從35 Hz升高至450 Hz
    | label3= 速度
    | data3 = 光速
    | label4= 引力應變
    | data4 = h<sub>peak</sub> ~ 3.4 x 10<sup>-22</sup>
   }}
 | data4 = {{Infobox | decat = yes | child = yes
    | header1 =波源參數
    | headerstyle = background:#00BFFF;
    | label2= 波源
    | data2 = 兩個黑洞併合
    | label3= 距離
    | data3 = [[紅移|z]] ~ 0.09（大約14億[[光年]]）
   }}
 | header5 = {{Infobox | decat = yes | child = yes
    | title = 波源質量{{noteTag|採波源參考系}}
    | label3= 主黑洞
    | data3 = ~ 14.2 {{solar mass}}
    | label4= 副黑洞
    | data4 = ~ 7.5 {{solar mass}}
    | label5= 併合後的黑洞
    | data5 = ~ 20.8 {{solar mass}}
   }}
 | belowstyle =
 | below = 來源：[[物理評論快報]]<ref name="PRL-20160615" />
}}
'''GW151226'''是由[[激光干涉引力波天文台#先进LIGO|先進激光干涉引力波天文台]]（aLIGO）于2015年12月26日探测到的[[引力波]]现象，是人类繼[[GW150914]]引力波事件後第二次直接探测到的引力波。相关探测结果是由[[LIGO]]與[[處女座干涉儀|VIRGO]]團隊于2016年6月15日宣布。这一束产生于双黑洞的引力波信号与广义相对论中对[[双黑洞]]旋近、併合以及併合后的黑洞会发生衰荡（ringdown）的理论预测相符。同时GW151226也是人类对双黑洞併合的第二度观测，再度展示了双黑洞系统确实存在，且其合并在宇宙的目前阶段仍能发生。<ref name="PRL-20160615">{{Cite journal|author1=LIGO Scientific Collaboration and Virgo Collaboration| author2=B. P. Abbott, et al| date=15 June 2016|title=GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence|url=http://link.aps.org/doi/10.1103/PhysRevLett.116.241103|journal=Physical Review Letters|volume= 116|issue= 24|pages=241103|doi=10.1103/PhysRevLett.116.241103}}</ref><ref>{{Cite web|url=http://physicsworld.com/cws/article/news/2016/jun/15/ligo-detects-second-black-hole-merger|title=LIGO detects second black-hole merger|last=|first=|date=15 June 2016|website=physicsworld.com|publisher=Institute of Physics|access-date=15 June 2016|archive-date=2017-09-21|archive-url=https://web.archive.org/web/20170921193437/http://physicsworld.com/cws/article/news/2016/jun/15/ligo-detects-second-black-hole-merger|dead-url=no}}</ref>

==物理描述==
兩個黑洞的質量分別為14.2 (+8.3, −3.7) [[太阳质量|{{solar mass}}]]與 7.5 (+2.3, −2.3) {{solar mass}}，它們總共釋出約1個太陽質量的引力波能量，最終併合形成了一個質量為20.8 (+6.1, −1.7) {{solar mass}}的黑洞，其發生地點離地球有14億光年之遠。位於美國[[路易斯安那州]]的[[利文斯頓 (路易斯安那州)|利文斯頓]]探測器先探測到引力波，1.1毫秒之後，位於美國[[华盛顿州]]的[[漢福德區|汉福德]]探測器也探測到引力波。<ref name="PRL-20160615" /><ref name="MIT"/>

從分析探測數據，[[LIGO]]與[[處女座干涉儀|VIRGO]]團隊估算出，在併合前，其中一個黑洞的自轉率為廣義相對論最大自轉率的20%；在併合後，最終黑洞的自轉率是限值的74%（±6%）。<ref>{{cite news |last=Cho |first=Adiran |url=http://www.sciencemag.org/news/2016/06/ligo-detects-another-black-hole-crash |title=LIGO detects another black hole crash |work=[[Science (journal)|Science]] News |date=15 June 2016 |accessdate=2016-06-16 |archive-date=2020-12-08 |archive-url=https://web.archive.org/web/20201208043021/https://www.sciencemag.org/news/2016/06/ligo-detects-another-black-hole-crash |dead-url=no }}</ref><ref name="PRL-20160615" />由於兩個黑洞的質量較小，最終軌道的時間特徵也不同，LIGO因此可以更詳細探測到黑洞併合前的最後階段。在1秒鐘的探測期內，信號頻率經過55次循環（27次環軌）從35 Hz增至450 Hz。與之相比較，第一次併合事件探測期的0.2秒內只有5次環軌。<ref name="PRL-20160615"/><ref>{{cite news |last=Ball |first=Philip |url=http://physics.aps.org/articles/v9/68 |title=Focus: LIGO Bags Another Black Hole Merger |work=American Physical Society |date=15 June 2016 |accessdate=2016-06-16 |archive-date=2021-01-26 |archive-url=https://web.archive.org/web/20210126124740/https://physics.aps.org/articles/v9/68 |dead-url=no }}</ref>

==在天文物理學的意義==
GW151226事件意味著，先前的發現並不是僥倖發生的事件，在浩瀚宇宙裏有很多會在未來發生併合事件的雙黑洞，人們必會探測到更多這類事件。<ref name=Castelvecchi_01>{{cite news |last=Castelvecchi |first=Davide |url=http://www.nature.com/news/ligo-detects-whispers-of-another-black-hole-merger-1.20093 |title=LIGO detects whispers of another black-hole merger |work=Nature News |date=15 June 2016 |accessdate=2016-06-16 |archive-date=2020-11-08 |archive-url=https://web.archive.org/web/20201108121833/http://www.nature.com/news/ligo-detects-whispers-of-another-black-hole-merger-1.20093 |dead-url=no }}</ref>

這次探測結果證實了[[廣義相對論]]適用於強引力場。之前，廣義相對論的強引力場預測從未被直接檢試過。這是廣義相對論第二次通過這嚴格檢試。<ref name="MIT">{{cite news|last1=Chu|first1=Jennifer|title=For second time, LIGO detects gravitational waves|url=http://news.mit.edu/2016/second-time-ligo-detects-gravitational-waves-0615|accessdate=15 June 2016|work=MIT News|publisher=MIT|date=June 15, 2016|archive-date=2016-06-16|archive-url=https://web.archive.org/web/20160616051000/http://news.mit.edu/2016/second-time-ligo-detects-gravitational-waves-0615|dead-url=no}}</ref><ref name="NYT-20160615">{{cite news |last=Overbye |first=Dennis |title=Scientists Hear a Second Chirp From Colliding Black Holes |url=http://www.nytimes.com/2016/06/16/science/ligo-gravitational-waves-einstein.html |date=June 15, 2016 |work=New York Times |accessdate=June 15, 2016 |archive-date=2019-04-11 |archive-url=https://web.archive.org/web/20190411151438/https://www.nytimes.com/2016/06/16/science/ligo-gravitational-waves-einstein.html |dead-url=no }}</ref>

==註釋==
{{noteFoot}}

== 参考文献 ==
{{Reflist}}

==外部連結==
{{wikinews|LIGO宣佈第二次探測到重力波}}
*[https://www.ligo.caltech.edu/news/ligo20160615 LIGO官方新聞稿] {{Wayback|url=https://www.ligo.caltech.edu/news/ligo20160615 |date=20201120052031 }} {{en icon}}
*[https://www.ligo.caltech.edu/detection LIGO探测专题] {{Wayback|url=https://www.ligo.caltech.edu/detection |date=20210126154316 }} {{en icon}}

==參見==
{{portal box|物理學|天文學}}
*[[重力波 (相對論)|重力波]]
*[[引力波天文学]]

{{引力波}}
{{2016 in space}}

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[[Category:引力波天文学]]
[[Category:廣義相對論]]
[[Category:實驗物理]]
[[Category:2016年科学]]
[[Category:2016年美国]]
[[Category:黑洞]]