主要内容:
在200多天后的观测发现O和Ni的发射线，暗示这个Ic型超新星产生了一个中子星。
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文章信息:
SN 2006aj Associated with XRF 060218 At Late Phases: Nucleosynthesis-Signature of A Neutron Star-Driven Explosion
Authors: Keiichi Maeda,
Koji Kawabata,
Masaomi Tanaka,
Ken'ichi Nomoto,
Nozomu Tominaga,
Takashi Hattori,
Takeo Minezaki,
Takami Kuroda,
Tomoharu Suzuki,
Jinsong Deng,
Paolo A. Mazzali,
Elena Pian
Abstract: Optical spectroscopy and photometry of SN 2006aj have been performed with the Subaru telescope at t > 200 days after GRB060218, the X-ray Flash with which it was associated. Strong nebular emission-lines with an expansion velocity of v ~ 7,300 km/s were detected. The peaked but relatively broad [OI]6300,6363 suggests the existence of ~ 2 Msun of materials in which ~1.3 Msun is oxygen. The core might be produced by a mildly asymmetric explosion. The spectra are unique among SNe Ic in (1) the absence of [CaII]7291,7324 emission, and (2) a strong emission feature at ~ 7400A, which requires ~ 0.05 Msun of newly-synthesized 58Ni. Such a large amount of stable neutron-rich Ni strongly indicates the formation of a neutron star. The progenitor and the explosion energy are constrained to 18 Msun
Comments:
Accepted for Publication in the Astrophysical Journal Letters (2007, ApJ, 658, L5). 8 pages, including 1 table and 3 figures. Typos corrected
Subjects:
Astrophysics (astro-ph)
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