First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey
We present the first discoveries from a survey of z 6 quasars using imaging data from the DECam Legacy Survey (DECaLS) in the optical, the UKIRT Deep Infrared Sky Survey (UKIDSS) and a preliminary version of the UKIRT Hemisphere Survey (UHS) in the near-IR, and ALLWISE in the mid-IR. DECaLS will i...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
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IOP Publishing
2017
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| Online Access: | https://eprints.nottingham.ac.uk/42338/ |
| _version_ | 1848796466026381312 |
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| author | Wang, Feige Fan, Xiaohui Yang, Jinyi Wu, Xue-Bing Yang, Qian Bian, Fuyan McGreer, Ian D. Li, Jiang-Tao Li, Zefeng Ding, Jiani Dey, Arjun Dye, S. Findlay, Joseph R. Green, Richard James, David Jiang, Linhua Lang, Dustin Lawrence, Andy Myers, Adam D. Ross, Nicholas P. Schlegel, David J. Shanks, Tom |
| author_facet | Wang, Feige Fan, Xiaohui Yang, Jinyi Wu, Xue-Bing Yang, Qian Bian, Fuyan McGreer, Ian D. Li, Jiang-Tao Li, Zefeng Ding, Jiani Dey, Arjun Dye, S. Findlay, Joseph R. Green, Richard James, David Jiang, Linhua Lang, Dustin Lawrence, Andy Myers, Adam D. Ross, Nicholas P. Schlegel, David J. Shanks, Tom |
| author_sort | Wang, Feige |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We present the first discoveries from a survey of z 6 quasars using imaging data from the DECam Legacy Survey (DECaLS) in the optical, the UKIRT Deep Infrared Sky Survey (UKIDSS) and a preliminary version of the UKIRT Hemisphere Survey (UHS) in the near-IR, and ALLWISE in the mid-IR. DECaLS will image 9000 deg2 of sky down to z AB ~ 23.0, and UKIDSS and UHS will map the northern sky at 0 < decl. < +60°, reaching J VEGA ~ 19.6 (5-σ). The combination of these data sets allows us to discover quasars at redshift z 7 and to conduct a complete census of the faint quasar population at z 6. In this paper, we report on the selection method of our search, and on the initial discoveries of two new, faint z 6 quasars and one new z = 6.63 quasar in our pilot spectroscopic observations. The two new z ~ 6 quasars are at z = 6.07 and z = 6.17 with absolute magnitudes at rest-frame wavelength 1450 Å being M 1450 = −25.83 and M 1450 = −25.76, respectively. These discoveries suggest that we can find quasars close to or fainter than the break magnitude of the Quasar Luminosity Function (QLF) at z 6. The new z = 6.63 quasar has an absolute magnitude of M 1450 = −25.95. This demonstrates the potential of using the combined DECaLS and UKIDSS/UHS data sets to find z 7 quasars. Extrapolating from previous QLF measurements, we predict that these combined data sets will yield ~200 z ~ 6 quasars to z AB < 21.5, ~1000 z ~ 6 quasars to z AB < 23, and ~30 quasars at z > 6.5 to J VEGA < 19.5. |
| first_indexed | 2025-11-14T19:48:25Z |
| format | Article |
| id | nottingham-42338 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:48:25Z |
| publishDate | 2017 |
| publisher | IOP Publishing |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-423382020-05-04T18:41:45Z https://eprints.nottingham.ac.uk/42338/ First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey Wang, Feige Fan, Xiaohui Yang, Jinyi Wu, Xue-Bing Yang, Qian Bian, Fuyan McGreer, Ian D. Li, Jiang-Tao Li, Zefeng Ding, Jiani Dey, Arjun Dye, S. Findlay, Joseph R. Green, Richard James, David Jiang, Linhua Lang, Dustin Lawrence, Andy Myers, Adam D. Ross, Nicholas P. Schlegel, David J. Shanks, Tom We present the first discoveries from a survey of z 6 quasars using imaging data from the DECam Legacy Survey (DECaLS) in the optical, the UKIRT Deep Infrared Sky Survey (UKIDSS) and a preliminary version of the UKIRT Hemisphere Survey (UHS) in the near-IR, and ALLWISE in the mid-IR. DECaLS will image 9000 deg2 of sky down to z AB ~ 23.0, and UKIDSS and UHS will map the northern sky at 0 < decl. < +60°, reaching J VEGA ~ 19.6 (5-σ). The combination of these data sets allows us to discover quasars at redshift z 7 and to conduct a complete census of the faint quasar population at z 6. In this paper, we report on the selection method of our search, and on the initial discoveries of two new, faint z 6 quasars and one new z = 6.63 quasar in our pilot spectroscopic observations. The two new z ~ 6 quasars are at z = 6.07 and z = 6.17 with absolute magnitudes at rest-frame wavelength 1450 Å being M 1450 = −25.83 and M 1450 = −25.76, respectively. These discoveries suggest that we can find quasars close to or fainter than the break magnitude of the Quasar Luminosity Function (QLF) at z 6. The new z = 6.63 quasar has an absolute magnitude of M 1450 = −25.95. This demonstrates the potential of using the combined DECaLS and UKIDSS/UHS data sets to find z 7 quasars. Extrapolating from previous QLF measurements, we predict that these combined data sets will yield ~200 z ~ 6 quasars to z AB < 21.5, ~1000 z ~ 6 quasars to z AB < 23, and ~30 quasars at z > 6.5 to J VEGA < 19.5. IOP Publishing 2017-04-11 Article PeerReviewed Wang, Feige, Fan, Xiaohui, Yang, Jinyi, Wu, Xue-Bing, Yang, Qian, Bian, Fuyan, McGreer, Ian D., Li, Jiang-Tao, Li, Zefeng, Ding, Jiani, Dey, Arjun, Dye, S., Findlay, Joseph R., Green, Richard, James, David, Jiang, Linhua, Lang, Dustin, Lawrence, Andy, Myers, Adam D., Ross, Nicholas P., Schlegel, David J. and Shanks, Tom (2017) First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey. Astrophysical Journal, 839 (1). 27/1-27/8. ISSN 1538-4357 galaxies: active galaxies: high-redshift quasars: emission lines quasars: general http://iopscience.iop.org/article/10.3847/1538-4357/aa689f/meta doi:10.3847/1538-4357/aa689f doi:10.3847/1538-4357/aa689f |
| spellingShingle | galaxies: active galaxies: high-redshift quasars: emission lines quasars: general Wang, Feige Fan, Xiaohui Yang, Jinyi Wu, Xue-Bing Yang, Qian Bian, Fuyan McGreer, Ian D. Li, Jiang-Tao Li, Zefeng Ding, Jiani Dey, Arjun Dye, S. Findlay, Joseph R. Green, Richard James, David Jiang, Linhua Lang, Dustin Lawrence, Andy Myers, Adam D. Ross, Nicholas P. Schlegel, David J. Shanks, Tom First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey |
| title | First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey |
| title_full | First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey |
| title_fullStr | First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey |
| title_full_unstemmed | First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey |
| title_short | First discoveries of z > 6 quasars with the DECam Legacy Survey and UKIRT hemisphere survey |
| title_sort | first discoveries of z > 6 quasars with the decam legacy survey and ukirt hemisphere survey |
| topic | galaxies: active galaxies: high-redshift quasars: emission lines quasars: general |
| url | https://eprints.nottingham.ac.uk/42338/ https://eprints.nottingham.ac.uk/42338/ https://eprints.nottingham.ac.uk/42338/ |