The recent discovery of enormous Lyα nebulae (ELANe), characterized by physical extents >200 kpc and Lyα luminosities >1044 erg s−1, provides a unique opportunity to study the intergalactic medium and circumgalactic medium in distant galaxies. Many existing ELANe detections are associated with local overdensities of active galactic nuclei (AGN). We have initiated a search for ELANe around regions containing pairs of quasi-stellar objects (QSOs) using the Palomar Cosmic Web Imager. The first study of this search, Cai et al., presented results of ELAN0101+0201, which was associated with a QSO pair at z = 2.45. In this study, all targets residing in QSO pair environments analyzed have Lyα detections, but only one of the four targets meets the classification criteria of an ELANe associated with a QSO pair region (z ∼ 2.87). The other three sample detections of Lyα nebulae do not meet the size and luminosity criteria to be classified as ELANe. We find kinematic evidence that the ELANe J1613 is possibly powered mostly by AGN outflows. The analysis of circularly averaged surface brightness profiles of emission from the Lyα regions shows that the Lyα emission around z ∼ 2 QSO pairs is consistent with emission around individual QSOs at z ∼ 2, which is fainter than that around z ∼ 3 QSOs. A larger sample of Lyα at z ∼ 2 will be needed to determine if there is evidence of redshift evolution when compared to nebular emissions at z ∼ 3 from other studies.
                      
                        Published August 1, 2023
                      
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                  Circumgalactic Lyα Nebulae in Overdense Quasar Pair Regions Observed with the Palomar Cosmic Web Imager
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© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
Resources supporting this work were provided by NSF AAG Grant 1716907 and the California Institute of Technology. Z.C. acknowledges National Key R&D Program of China (grant No. 2018YFA0404503), the National Science Foundation of China (grant No. 12073014). The science research grants from the China Manned Space Project with No. CMS-CSST2021-A05.
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- ISSN
 - 1538-4357
 
Funding
- National Science Foundation
 - AST-1716907
 - California Institute of Technology
 - Ministry of Science and Technology of the People's Republic of China
 - 2018YFA0404503
 - National Natural Science Foundation of China
 - 12073014
 - China National Space Administration
 - CMS-CSST2021-A05