ADF22: Blind detections of [CII] line emitters shown to be spurious

Natsuki H. Hayatsu; Rob J. Ivison; Paola Andreani; Hideki Umehata; Yuichi Matsuda; Naoki Yoshida; Kotaro Kohno; Bunyo Hatsukade; Akio K. Inoue; Yoichi Tamura; Tutomu T. Takeuchi; Seiji Fujimoto; Minju M. Lee; Tohru Nagao; Yiping Ao

arXiv · 1907.05742

ADF22: Blind detections of [CII] line emitters shown to be spurious

Natsuki H. Hayatsu·Rob J. Ivison·Paola Andreani·Hideki Umehata·Yuichi Matsuda·Naoki Yoshida·Kotaro Kohno·Bunyo Hatsukade·Akio K. Inoue·Yoichi Tamura·Tutomu T. Takeuchi·Seiji Fujimoto·Minju M. Lee·Tohru Nagao·Yiping Ao

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Abstract

We report Atacama Large Millimetre/submillimeter Array (ALMA) Cycle-5 follow-up observations of two candidate [CII] emitters at z ~ 6 in the ALMA deep field in SSA22 (ADF22). The candidates were detected blindly in a Cycle-2 ALMA survey covering ~ 5 square arcmins, with a single tuning, along with two CO lines associated with galaxies at lower redshifts. Various tests suggested at least one of the two > 6-sigma [CII] candidates should be robust (Hayatsu et al. 2017). Nevertheless, our new, deeper observations recover neither candidate, demonstrating a higher contamination rate than expected. The cause of the spurious detections is under investigation but at present it remains unclarified.

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Natsuki H. Hayatsu, Rob J. Ivison, Paola Andreani, Hideki Umehata, Yuichi Matsuda, Naoki Yoshida, Kotaro Kohno, Bunyo Hatsukade, Akio K. Inoue, Yoichi Tamura, Tutomu T. Takeuchi, Seiji Fujimoto, Minju M. Lee, Tohru Nagao, Yiping Ao. 2019-07-12. ADF22: Blind detections of [CII] line emitters shown to be spurious. https://arxiv.org/abs/1907.05742

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