论文标题
天体物理距离尺度JAGB方法：I。校准和第一个应用
Astrophysical Distance Scale The JAGB Method: I. Calibration and a First Application
论文作者
论文摘要
J分支渐近巨型分支（JAGB）恒星是一个具有光度良好的人群，具有极端红色的中级AGB恒星，被发现在近红外具有紧密约束的亮度。 Based on JK photometry of some 3,300 JAGB stars in the bar of the Large Magellanic Cloud (LMC) we find that these very red AGB stars have a constant absolute magnitude of <M_J> = -6.22 mag, adopting the Detached Eclipsing Binary (DEB) distance to the LMC of 18.477 +/- 0.004 (stat) +/- 0.026 (sys).在SMC中进行第二次独立校准，该校准也具有DEB几何距离，我们发现<m_j> = -6.18 +/- $ 0.01（stat）+/- 0.05〜（sys）mag。对于单个观测值，散射为+/- 0.27 mag（跌至+/- 0.15〜MAG，用于在超过一年的窗口上平均多个观测值）。我们暂时采用<m_j> = -6.20 mag +/- 0.01（stat）+/- 0.04（sys）mag，用于JAGB星的平均绝对幅度。将此校准应用于最近在Galaxy NGC 253中观察到的JAGB恒星，我们确定距离模量为27.66 +/- 0.01（STAT）+/- 0.04 MAG（SYS），对应于3.40 +/- 0.06 MPC（STAT）。这与27.68 +/- 0.05 mag的平均TRGB距离模量非常吻合，假设M_I = -4.05 mag trgb零点。
J-Branch Asymptotic Giant Branch (JAGB) stars are a photometrically well-defined population of extremely red, intermediate-age AGB stars that are found to have tightly-constrained luminosities in the near-infrared. Based on JK photometry of some 3,300 JAGB stars in the bar of the Large Magellanic Cloud (LMC) we find that these very red AGB stars have a constant absolute magnitude of <M_J> = -6.22 mag, adopting the Detached Eclipsing Binary (DEB) distance to the LMC of 18.477 +/- 0.004 (stat) +/- 0.026 (sys). Undertaking a second, independent calibration in the SMC, which also has a DEB geometric distance, we find <M_J> = -6.18 +/- $ 0.01 (stat) +/- 0.05~(sys) mag. The scatter is +/-0.27 mag for single-epoch observations, (falling to +/-0.15~mag for multiple observations averaged over a window of more than one year). We provisionally adopt <M_J> = -6.20 mag +/- 0.01 (stat) +/- 0.04 (sys) mag for the mean absolute magnitude of JAGB stars. Applying this calibration to JAGB stars recently observed in the galaxy NGC 253, we determine a distance modulus of 27.66 +/- 0.01(stat) +/- 0.04 mag (sys), corresponding to a distance of 3.40 +/- 0.06 Mpc (stat). This is in excellent agreement with the averaged TRGB distance modulus of 27.68 +/- 0.05 mag, assuming M_I = -4.05 mag for the TRGB zero point.
