arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0908.4079astro-ph.CO
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一个QSO宿主星系及其z=6.43的Lyalpha辐射

A QSO host galaxy and its Lyalpha emission at z=6.43

Tomotsugu Goto, Yousuke Utsumi, Hisanori Furusawa, Satoshi Miyazaki, Yutaka Komiyama

摘要:

本文报道了在Subaru/Suprime-Cam的深z'和z_r波段图像中观测到z=6.43的类星体(CFHQSJ 2329 -0301,目前已知的最高红移的类星体)周围的扩展结构。经过仔细的PSF(QSO)扣除后,z '波段的结构在天空中延伸超过4“(R_e=11 kpc),因此,分辨率很好(16 sigma检测)。减去PSF的z_r-能带结构的形状与z '-带中的形状相似,但是对于3 σ检测不太显著。在z '波段,类星体+主体的径向轮廓在0.8- 3“半径范围内明显超过平均PSF。由于z '带包括z=6.43处的Lya发射,因此z'通量可能是主体(连续光)及其Lya发射的混合物,而z_r带通量来自主体。通过SED建模,我们估计40%的减去PSF的z '带光来自主体(连续谱),60%来自Lya发射。宿主的绝对星等为M_{1450} =-23.9(c.f. M_{1450} =-26.4(对于类星体)。SFR(Lya)的下限为1.6 Msun yr^{-1},假设年龄为1亿年,恒星质量范围为6.2 x 10^8 ~ 1.1 x 10^10 Msun。探测结果显示,在大爆炸后约8.4亿年后的早期宇宙中,一个明亮的类星体已经被一个巨大的恒星形成星系所庇护。宿主可能是一个正在形成的巨大星系,与一个超大质量黑洞共同进化。

英文摘要:

We report an optical detection of an extended structure around a QSO at z=6.43 (CFHQSJ2329-0301, the highest redshift QSO currently known) in deep z' and z_r-band images of the Subaru/Suprime-Cam. After a careful PSF (QSO) subtraction, a structure in the z'-band extends more than 4'' on the sky (R_e=11 kpc), and thus, is well-resolved (16sigma detection). The PSF-subtracted z_r-band structure is in a similar shape to that in the z'-band, but less significant with a 3 sigma detection. In the z'-band, a radial profile of the QSO+host shows a clear excess over that of the averaged PSF in 0.8-3'' radius. Since the z'-band includes a Lya emission at z=6.43, the z' flux is perhaps a mixture of the host (continuum light) and its Lya emission, whereas the z_r-band flux is from the host. Through a SED modeling, we estimate 40% of the PSF-subtracted z'-band light is from the host (continuum) and 60% is from Lya emission. The absolute magnitude of the host is M_{1450}=-23.9 (c.f. M_{1450}=-26.4 for the QSO). A lower limit of the SFR(Lya) is 1.6 Msun yr^{-1} with stellar mass ranging 6.2 x 10^8 to 1.1 x 10^10 Msun when 100 Myrs of age is assumed. The detection shows that a luminous QSO is already harbored by a large, star-forming galaxy in the early Universe only after ~840 Myr after the big bang. The host may be a forming giant galaxy, co-evolving with a super massive black hole.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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