日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 P (宇宙惑星科学) » P-CG 宇宙惑星科学複合領域・一般

[P-CG24] アルマによる惑星科学の新展開

2019年5月29日(水) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:武藤 恭之(工学院大学 教育推進機構)、百瀬 宗武(茨城大学理学部)、佐川 英夫(京都産業大学理学部)、下条 圭美(国立天文台)

[PCG24-P03] スパースモデリングによる原始惑星系円盤 HD142527の超解像イメージング

*山口 正行1,2秋山 和徳3,2片岡 章雅2,6塚越 崇2武藤 恭之4池田 思朗5深川 美里2本間 希樹2,6川邊 良平2,1,6 (1.東京大学、2.国立天文台、3.マサチューセッツ工科大学ヘイスタック観測所、4.工学院大学、5.統計数理研究所、6.総合研究大学大学院)

キーワード:アルマ望遠鏡、電波干渉計、画像再構成技術、原始惑星系円盤、惑星形成

Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations have provided new insights for planet formation process and simultaneously highlighted fundamental importance to pursue higher angular resolutions of observations to address opened questions. With the emphasis on improving the fidelity even at a super-resolution regime, many imaging techniques have been intensively developed in the last several years, which may provide substantial improvements in interferometric observations of protoplanetary disks. The CLEAN technique has been widely used, but recently, a new technique using the sparse modeling approach is suggested. This technique directly solves a set of undetermined equations and has been shown to behave better than the CLEAN technique based on mock observations with VLBI (Very Long Baseline Interferometry). However, it has never been applied to ALMA-like connected interferometers nor real observational data. In this work, for the first time, the sparse modeling technique is applied to observational data sets taken by ALMA. We evaluate the performance of the technique by comparing the resulting images with those derived by the CLEAN technique. We use two sets of ALMA archival data at Band 7 (~350GHz) for the protoplanetary disk around HD 142527. One is taken in the intermediate-baseline array configuration, and the other is in the longer-baseline array configuration. The image resolutions reconstructed from these data sets are different by a factor of ~ 3. With the two data sets independently taken by different array configurations, we show that SpM indeed achieves a higher fidelity than a multi-scale CLEAN technique, and provides consistent images from two data sets even beyond significant differences in angular resolutions by a factor ~ 3-4. Two SpM images consistently resolve radially and azimuthally asymmetric dust-grain emission of the outer disk, including a non-circular ridge shape well characterized by a simple logarithmic spiral. Resolved asymmetric structure of the outer disk provided by two SpM images may suggest complex gas kinematics near the inner-edge of the outer disk. Our results demonstrate that ongoing intensive developments of new imaging techniques will be ubiquitously beneficial to current and next-generation radio interferometers.