evn:evn_science
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evn:evn_science [2017/08/07 12:20] – [No AGN evidence in NGC 1614 from deep radio VLBI observations] michael.lindqvist | evn:evn_science [2018/09/12 09:12] – antonis | ||
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+ | =====Gravitationally-lensed radio arcs observed with global VLBI===== | ||
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+ | [[https:// | ||
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+ | The Strong lensing at High Angular ResoluTon Program (SHARP) led by McKean (ASTRON) has | ||
+ | obtained a deep global VLBI observaTon of the gravitaTonal lens MG J0751+2716 at 1.65 GHz | ||
+ | (project GM070; PI: McKean). The 18.5 hours observation used 24 antennas from the EVN and | ||
+ | the VLBA, including the large apertures (> 50 m) of the Lovell, Effelsberg, Robledo and Green Bank | ||
+ | telescopes. Data were recorded at 512 Mbps and correlated at JIVE to produce 8 spectral | ||
+ | windows (IFs) with 8 MHz bandwidth and 32 channels each, through both circular polarisaTons. | ||
+ | MG J0751+2716 is one of the few quadruply imaged radio-loud gravitationally lensed quasars that | ||
+ | show extended arcs on VLBI-scales. The global VLBI L-band deep imaging detects all of the extended | ||
+ | arcs at high significance, | ||
+ | source in unprecedented detail (see Figure). Because of the complexity of this system, the imaging was | ||
+ | performed using multi-scale cleaning within the wsclean algorithm (Offringa et al. 2014). The total | ||
+ | flux density of the target is 350 mJy and the off-source rms is 41 μJy/beam. Never before have such | ||
+ | extended (200-600 mas) gravitaTonal arcs been detected at an angular resoluTon of a few mas. The | ||
+ | excellent uv-coverage and surface brightness sensiTvity provided by the global VLBI array have been | ||
+ | fundamental for a precise study of the structure of the extended arcs on mas-scales from | ||
+ | MG J0751+2716. | ||
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+ | {{: | ||
+ | **Figure 1.**Global VLBI imaging of MG J0751+2716 at 1.65 GHz (Spingola et al. (2018)). The off-source | ||
+ | rms is 41 μJy/beam and the peak surface brightness is 2.9 mJy/beam. The restored beam is 5.5x1.8 | ||
+ | mas, and is shown within the white box in the bottom-hand corner. | ||
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===== The Repeating Fast Radio Burst FRB 121102 as seen on milliarcsecond angular scales ===== | ===== The Repeating Fast Radio Burst FRB 121102 as seen on milliarcsecond angular scales ===== | ||
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+ | **Figure 7.** | ||
+ | EVN maps of the detected compact source at the C band (5.0 GHz; left-hand panel) and the X band (8.4 GHz; right-hand panel). | ||
evn/evn_science.txt · Last modified: 2021/05/03 07:30 by kazi