The VST ATLAS quasar survey I: Catalogue of photometrically selected quasar candidates
The VST ATLAS quasar survey I: Catalogue of photometrically selected quasar candidates
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VST ATLAS 类星体调查 I：光度选择的候选类星体目录
DOI：
10.1093/mnras/stad516
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发表时间：
2023
影响因子：
4.8
通讯作者：
Eltvedt A
中科院分区：
文献类型：
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作者：
Eltvedt A
我们介绍了VST ATLAS类星体巡天，包括1229000个类星体（QSO）候选者，16 <g< 22.5超过124700 deg 2。该目录基于VST ATLAS+NEOWISE成像巡天，目标是达到< 2.2的类星体天空密度为130 deg− 2，> 2.2的类星体天空密度为130 deg− 2。为了指导我们的选择，我们使用了扩展的威廉·赫歇尔深场（WHDF）中的X射线/紫外/光学/MIR数据，在那里我们发现ag< 22.5的宽线类星体密度为269 ± 67 deg−2，与预期的大约196 deg−2大致一致。我们发现，我们的类星体的百分之二十五的形态分类为光学扩展。总的来说，我们发现在这些深度数据中，MIR，UV和X射线的选择完成了70%-90%，而X射线受到的污染比MIR和UV少。然而，MIR比X射线或UV更敏感，在g < 22.5和ergs cm−2s− 1的限制下，它对> 2.2类星体更敏感。我们调整了我们以前的2 QDES试点调查的选择标准，并优先考虑显示UV和MIR过量的VST ATLAS候选人，还选择了最初分类为扩展的候选人。我们使用DESI（将在DR 1中发布）和2dF的数据来测试我们的选择，以估计效率和完整性，我们使用ANNz 2来确定光度红移。应用在4700度2的ATLAS区域，我们得到了472000个可能小于2.2的类星体候选者，这意味着天空密度为1000度2，我们的WHDF分析表明，当包括ROSITAX射线候选者时，它将上升到至少130度2。在大于2.2时，我们发现了大约310000个候选天体，其中169000个可能是天空密度为360度−2的类星体。
We present the VST ATLAS Quasar Survey, consisting of ∼1229 000 quasar (QSO) candidates with 16 <g< 22.5 over ∼4700 deg2. The catalogue is based on VST ATLAS+NEOWISE imaging surveys and aims to reach a QSO sky density of 130 deg−2for< 2.2 and ∼30 deg−2for> 2.2. To guide our selection, we use X-ray/UV/optical/MIR data in the extended William Herschel Deep Field (WHDF) where we find ag< 22.5 broad-line QSO density of 269 ± 67 deg−2, roughly consistent with the expected ∼196 deg−2. We find that ∼25 per cent of our QSOs are morphologically classed as optically extended. Overall, we find that in these deep data, MIR, UV, and X-ray selections are ∼70–90 per cent complete while X-ray suffers less contamination than MIR and UV. MIR is however more sensitive than X-ray or UV to> 2.2 QSOs atg< 22.5 and theergs cm−2s−1limit ofeROSITA. We adjust the selection criteria from our previous 2QDES pilot survey and prioritize VST ATLAS candidates that show both UV and MIR excess, also selecting candidates initially classified as extended. We test our selections using data from DESI (which will be released in DR1) and 2dF to estimate the efficiency and completeness, and we use ANNz2 to determine photometric redshifts. Applying over the ∼4700 deg2ATLAS area gives usQSO candidates of which 472 000 are likely to be< 2.2 QSOs, implying a sky density of ∼100 deg−2, which our WHDF analysis suggests will rise to at least 130 deg−2wheneROSITAX-ray candidates are included. At> 2.2, we find ∼310() 000 candidates, of which 169 000 are likely to be QSOs for a sky density of ∼36 deg−2.