We present the first discoveries from a survey of z greater than or similar to 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 deg(2) of sky down to z(AB) similar to 23.0, and UKIDSS and UHS will map the northern sky at 0 < decl. < + 60 degrees, reaching J(VEGA) similar to 19.6 (5-sigma). The combination of these data sets allows us to discover quasars at redshift z greater than or similar to 7 and to conduct a complete census of the faint quasar population at z greater than or similar to 6. In this paper, we report on the selection method of our search, and on the initial discoveries of two new, faint z greater than or similar to 6 quasars and one new z = 6.63 quasar in our pilot spectroscopic observations. The two new z similar to 6 quasars are at z = 6.07 and z = 6.17 with absolute magnitudes at rest-frame wavelength 1450 angstrom 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 greater than or similar to 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 greater than or similar to 7 quasars. Extrapolating from previous QLF measurements, we predict that these combined data sets will yield similar to 200 z similar to 6 quasars to z(AB) < 21.5, similar to 1000 z similar to 6 quasars to z(AB) < 23, and similar to 30 quasars at z > 6.5 to J(VEGA) < 19.5.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/624728 |
| Date | 11 April 2017 |
| Creators | 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, Simon, Findlay, Joseph R., Green, Richard, James, David, Jiang, Linhua, Lang, Dustin, Lawrence, Andy, Myers, Adam D., Ross, Nicholas P., Schlegel, David J., Shanks, Tom |
| Contributors | Univ Arizona, Steward Observ |
| Publisher | IOP PUBLISHING LTD |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2017. The American Astronomical Society. All rights reserved. |
| Relation | http://stacks.iop.org/0004-637X/839/i=1/a=27?key=crossref.659d362b0d97bc805aa686437a5fa0c6 |
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