DISCOVERY OF THREE z > 6.5 QUASARS IN THE VISTA KILO-DEGREE INFRARED GALAXY (VIKING) SURVEY
DISCOVERY OF THREE z > 6.5 QUASARS IN THE VISTA KILO-DEGREE INFRARED GALAXY (VIKING) SURVEY
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DOI：
10.1088/0004-637x/779/1/24
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发表时间：
2013-11
期刊：
影响因子：
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通讯作者：
B. Venemans;J. Findlay;W. Sutherland;G. D. Rosa;R. McMahon;R. Simcoe;E. González-Solares;K. Kuijken-K.
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文献类型：
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作者：
B. Venemans;J. Findlay;W. Sutherland;G. D. Rosa;R. McMahon;R. Simcoe;E. González-Solares;K. Kuijken-K.
研究最高红移的类星体可以限制星系和黑洞形成的模型，也可以探索早期宇宙中的星系际介质。迄今为止，光学勘测已经发现了60多个z ≥ 6.4的类星体，这是使用z波段和CCD探测器设定的极限。只有一个z = 6.4的类星体被发现，即z = 7.08的类星体ULAS J1120+0641，使用近红外成像。在这里，我们报告发现了三个新的z = 6.4类星体在332 deg 2的可见光和红外巡天望远镜天文学千度红外星系（维京海盗）调查，从而扩大了数量从1到4。新发现的类星体的红移分别为z = 6.60、6.75和6.89。绝对星等介于−26.0和−25.5之间，比ULAS J1120+0641暗0.6-1.1等。近红外光谱显示镁二发射线在所有三个对象。类星体由质量为1 ×（1-2）× 109 M的黑洞提供动力。在我们探测到的6.44 109 M的红移范围内，> 1.1 × 10−9 Mpc−3。在我们的调查区域发现的三个类星体与z = 6的类星体光度函数外推到z = 7时是一致的。我们没有发现类星体的空间密度随着红移从z = 6到z = 7的增加而急剧下降的证据。
Studying quasars at the highest redshifts can constrain models of galaxy and black hole formation, and it also probes the intergalactic medium in the early universe. Optical surveys have to date discovered more than 60 quasars up to z ≃ 6.4, a limit set by the use of the z-band and CCD detectors. Only one z ≳ 6.4 quasar has been discovered, namely the z = 7.08 quasar ULAS J1120+0641, using near-infrared imaging. Here we report the discovery of three new z ≳ 6.4 quasars in 332 deg2 of the Visible and Infrared Survey Telescope for Astronomy Kilo-degree Infrared Galaxy (VIKING) survey, thus extending the number from 1 to 4. The newly discovered quasars have redshifts of z = 6.60, 6.75, and 6.89. The absolute magnitudes are between −26.0 and −25.5, 0.6–1.1 mag fainter than ULAS J1120+0641. Near-infrared spectroscopy revealed the Mg ii emission line in all three objects. The quasars are powered by black holes with masses of ∼(1–2) × 109 M☉. In our probed redshift range of 6.44 109 M☉) > 1.1 × 10−9 Mpc−3. The discovery of three quasars in our survey area is consistent with the z = 6 quasar luminosity function when extrapolated to z ∼ 7. We do not find evidence for a steeper decline in the space density of quasars with increasing redshift from z = 6 to z = 7.