FRB 150418: clues to its nature from European VLBI Network and e-MERLIN observations
FRB 150418: clues to its nature from European VLBI Network and e-MERLIN observations
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DOI：
10.1051/0004-6361/201629172
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发表时间：
2016-09
影响因子：
6.5
通讯作者：
M. Giroletti;B. Marcote;M. Garrett;Z. Paragi;J. Yang;K. Hada;T. Muxlow;C. C. C. Inafira-C.-C.;JIV-ERIC;Astron;C. Univ.;Naoj;Jbca;Nrl
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作者：
M. Giroletti;B. Marcote;M. Garrett;Z. Paragi;J. Yang;K. Hada;T. Muxlow;C. C. C. Inafira-C.-C.;JIV-ERIC;Astron;C. Univ.;Naoj;Jbca;Nrl
目的：我们调查的性质紧凑，可能是可变的核射电源的中心WISE J 0716 -19，建议的宿主星系的快速射电暴FRB 150418。方法：我们在2016年3月16日至6月2日期间使用欧洲VLBI网络（EVN）在5.0 GHz处观察了WISE J 0716 -19四次。在三个时期，我们同时观察到的源与e-MERLIN在相同的频率。结果：我们在每个时期的EVN数据中检测到一个紧凑的源，其显著性高达~8σ。这四个时期的峰值表面强度和位置的不确定性内产生一致的结果。这些量的平均值为：Ipeak =（115 ± 9）μJy梁-1，RA = 07 h 16 m 34.55496（7）s，Dec = -19 ° 00 '39.4754（8 μ“）。e-MERLIN数据在与EVN数据一致的位置提供了~3-5σ检测。在EVN和e-MERLIN之间的角度尺度上的发射与零一致。EVN核心的亮度温度为Tb = 108.5 K，接近先前解释WISE J 0716 -19的星际闪烁短期射电变率所需的数值。结论：我们的观测提供了WISE J 0716 -19中核致密源的直接和独立的证据，这是一种与FRB 150418没有明显联系的物理场景。然而，EVN数据并不表明VLA观察到的变异性。
Aims: We investigate the nature of the compact and possibly variable nuclear radio source in the centre of WISE J0716-19, the proposed host galaxy of the fast radio burst FRB 150418. Methods: We observed WISE J0716-19 at 5.0 GHz with the European VLBI Network (EVN) four times between 2016 March 16 and June 2. At three epochs, we simultaneously observed the source with e-MERLIN at the same frequency. Results: We detected a compact source in the EVN data in each epoch with a significance of up to ~8σ. The four epochs yielded consistent results within their uncertainties for the peak surface intensity and positions. The mean values for these quantities are Ipeak = (115 ± 9)μJy beam-1 and RA = 07h16m34.55496(7)s, Dec = -19°00'39.4754(8)''. The e-MERLIN data provided ~3-5σ detections at a position consistent with those of the EVN data. The emission on angular scales intermediate between the EVN and e-MERLIN is consistent with being null. The brightness temperature of the EVN core is Tb ≳ 108.5 K, close to the value previously required to explain the short-term radio variability properties of WISE J0716-19 in terms of interstellar scintillation. Conclusions: Our observations provide direct and independent evidence of a nuclear compact source in WISE J0716-19, a physical scenario without evident connection with FRB 150418. However, the EVN data do not indicate the variability observed with the VLA.