A Lyα-only Active Galactic Nucleus from the Sloan Digital Sky Survey
A Lyα-only Active Galactic Nucleus from the Sloan Digital Sky Survey
复制标题
来自斯隆数字巡天的仅 Lyα 活动星系核
DOI：
10.1086/420804
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
S. Snedden
中科院分区：
文献类型：
--
作者：
P. Hall;E. Hoversten;C. Tremonti;D. Berk;D. Schneider;M. Strauss;G. Knapp;D. York;D. Hutsemékers;P. Newman;J. Brinkmann;B. Frye;M. Fukugita;K. Glazebrook;M. Harvanek;T. Heckman;Ž. Ivezić;S. Kleinman;J. Krzesinski;D. Long;E. Neilsen;M. Niederste;A. Nitta;D. Schlegel;S. Snedden
斯隆数字巡天发现了一个z = 2.4917的射电大声活动星系核（AGN），它具有明亮的、可变的、低偏振紫外连续谱、H I双光子发射和中等宽的Lyα线（FWHM <$1430 km s-1），但没有明显的金属线发射。SDSS J113658.36+024220.1在三个不同的狭窄系统中确实有相关的金属线吸收，速度范围为2710 km s-1。尽管有某些光谱相似性，SDSS J1136+0242不是一个莱曼破裂星系。相反，Lyα和双光子发射可以归因于一个扩展的，低金属含量的窄线区域。非极化连续统认为，我们看到SDSS J1136+0242非常接近任何电离锥的轴。对于为什么我们在SDSS J1136+0242的“正面射电星系”模型中看到强紫外连续谱而没有宽线发射，我们可以设想两种合理的解释：连续谱可以是淹没宽线发射的相对论波束同步加速器发射，或者更可能的是，SDSS J1136+0242可以类似于PG 1407+265，一个类星体，由于某种未知的原因，其高电离发射线非常宽，非常弱，并且高度蓝移。
The Sloan Digital Sky Survey has discovered a z = 2.4917 radio-loud active galactic nucleus (AGN) with a luminous, variable, low-polarization UV continuum, H I two-photon emission, and a moderately broad Lyα line (FWHM ≃ 1430 km s-1) but without obvious metal-line emission. SDSS J113658.36+024220.1 does have associated metal-line absorption in three distinct, narrow systems spanning a velocity range of 2710 km s-1. Despite certain spectral similarities, SDSS J1136+0242 is not a Lyman break galaxy. Instead, the Lyα and two-photon emission can be attributed to an extended, low-metallicity narrow-line region. The unpolarized continuum argues that we see SDSS J1136+0242 very close to the axis of any ionization cone present. We can conceive of two plausible explanations for why we see a strong UV continuum but no broad-line emission in this "face-on radio galaxy" model for SDSS J1136+0242: the continuum could be relativistically beamed synchrotron emission that swamps the broad-line emission, or more likely, SDSS J1136+0242 could be similar to PG 1407+265, a quasar in which for some unknown reason the high-ionization emission lines are very broad, very weak, and highly blueshifted.
影响因子：
6.5
作者：
J. Vernet;R. Fosbury;M. Villar-Martin;M. Cohen;A. Cimatti;S. Di;S. Alighieri;R. Goodrich
通讯作者：
J. Vernet;R. Fosbury;M. Villar-Martin;M. Cohen;A. Cimatti;S. Di;S. Alighieri;R. Goodrich