Bright Merger-nova Emission Powered by Magnetic Wind from a Newborn Black Hole
Bright Merger-nova Emission Powered by Magnetic Wind from a Newborn Black Hole
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DOI：
10.3847/2041-8213/aaa0cd
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
Shuai-Bing Ma;W. Lei;He Gao;Wei Xie;Wei Chen;Bing Zhang;Ding-xiong Wang
中科院分区：
文献类型：
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作者：
Shuai-Bing Ma;W. Lei;He Gao;Wei Xie;Wei Chen;Bing Zhang;Ding-xiong Wang
中子星-中子星星（NS-NS）或中子星-黑洞（NS-BH）双星的合并是引力波的候选源。至少有一小部分的合并残余物应该是一个恒星质量BH与亚相对论喷出物。准直射流通过Blandford-Znajek机制从中央BH发射，以触发短伽马射线爆发（sGRB）。同时，近各向同性风可能是由布兰德福德-佩恩机制（BP）驱动的。在以前的工作中，从BP机制注入到喷出物的额外能量被忽略了，而放射性衰变一直被认为是千诺瓦能量的主要来源。在这封信中，我们提出，风驱动的BP机制从新生的BH的磁盘可以加热和推动喷出物在即时发射阶段，甚至在后期的时候，有回落吸积。这样一个由BP驱动的合并新星即使对于低光度的sGRB也可以在光学波段明亮。一个GW合并事件的检测与BH明确确定为残留物，伴随着一个明亮的合并新星，将提供强有力的确认我们的模型。
Mergers of neutron star–neutron star (NS–NS) or neutron star–black hole (NS–BH) binaries are candidate sources of gravitational waves (GWs). At least a fraction of the merger remnants should be a stellar mass BH with sub-relativistic ejecta. A collimated jet is launched via the Blandford–Znajek mechanism from the central BH to trigger a short gamma-ray burst (sGRB). At the same time, a near-isotropic wind may be driven by the Blandford–Payne mechanism (BP). In previous work, additional energy injection to the ejecta from the BP mechanism was ignored, and radioactive decay has long been thought to be the main source of the kilonova energy. In this Letter, we propose that the wind driven by the BP mechanism from the newborn BH’s disk can heat up and push the ejecta during the prompt emission phase or even at late times when there is fall-back accretion. Such a BP-powered merger-nova could be bright in the optical band even for a low-luminosity sGRB. The detection of a GW merger event with a BH clearly identified as a remnant, accompanied by a bright merger-nova, would provide robust confirmation of our model.