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Title: First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey

Abstract

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 deg{sup 2} of sky down to z {sub AB} ∼ 23.0, and UKIDSS and UHS will map the northern sky at 0 < decl. < +60°, reaching J {sub 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 {sub 1450} = −25.83 and M {sub 1450} = −25.76, respectively. These discoveries suggest that we canmore » 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 {sub 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 {sub AB} < 21.5, ∼1000 z ∼ 6 quasars to z {sub AB} < 23, and ∼30 quasars at z > 6.5 to J {sub VEGA} < 19.5.« less

Authors:
; ; ; ;  [1]; ; ; ;  [2];  [3];  [4];  [5];  [6]; ;  [7];  [8];  [9];  [10]; ;  [11] more »; « less
  1. Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)
  2. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  3. Research School of Astronomy and Astrophysics, Australian National University, Weston Creek, ACT 2611 (Australia)
  4. Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI, 48109 (United States)
  5. National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)
  6. School of Physics and Astronomy, Nottingham University, University Park, Nottingham, NG7 2RD (United Kingdom)
  7. Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States)
  8. Cerro Tololo Inter-American Observatory, Casilla 603 La Serena (Chile)
  9. Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
  10. Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario, M5S 3H4 (Canada)
  11. Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)
Publication Date:
OSTI Identifier:
22661153
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 839; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; GALAXIES; QUASARS; RED SHIFT

Citation Formats

Wang, Feige, Yang, Jinyi, Wu, Xue-Bing, Yang, Qian, Li, Zefeng, Fan, Xiaohui, McGreer, Ian D., Ding, Jiani, Green, Richard, Bian, Fuyan, Li, Jiang-Tao, Dey, Arjun, Dye, Simon, Findlay, Joseph R., Myers, Adam D., James, David, Jiang, Linhua, Lang, Dustin, Lawrence, Andy, Ross, Nicholas P., and and others. First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA689F.
Wang, Feige, Yang, Jinyi, Wu, Xue-Bing, Yang, Qian, Li, Zefeng, Fan, Xiaohui, McGreer, Ian D., Ding, Jiani, Green, Richard, Bian, Fuyan, Li, Jiang-Tao, Dey, Arjun, Dye, Simon, Findlay, Joseph R., Myers, Adam D., James, David, Jiang, Linhua, Lang, Dustin, Lawrence, Andy, Ross, Nicholas P., & and others. First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey. United States. doi:10.3847/1538-4357/AA689F.
Wang, Feige, Yang, Jinyi, Wu, Xue-Bing, Yang, Qian, Li, Zefeng, Fan, Xiaohui, McGreer, Ian D., Ding, Jiani, Green, Richard, Bian, Fuyan, Li, Jiang-Tao, Dey, Arjun, Dye, Simon, Findlay, Joseph R., Myers, Adam D., James, David, Jiang, Linhua, Lang, Dustin, Lawrence, Andy, Ross, Nicholas P., and and others. Mon . "First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey". United States. doi:10.3847/1538-4357/AA689F.
@article{osti_22661153,
title = {First Discoveries of z > 6 Quasars with the DECam Legacy Survey and UKIRT Hemisphere Survey},
author = {Wang, Feige and Yang, Jinyi and Wu, Xue-Bing and Yang, Qian and Li, Zefeng and Fan, Xiaohui and McGreer, Ian D. and Ding, Jiani and Green, Richard and Bian, Fuyan and Li, Jiang-Tao and Dey, Arjun and Dye, Simon and Findlay, Joseph R. and Myers, Adam D. and James, David and Jiang, Linhua and Lang, Dustin and Lawrence, Andy and Ross, Nicholas P. and and others},
abstractNote = {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 deg{sup 2} of sky down to z {sub AB} ∼ 23.0, and UKIDSS and UHS will map the northern sky at 0 < decl. < +60°, reaching J {sub 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 {sub 1450} = −25.83 and M {sub 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 {sub 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 {sub AB} < 21.5, ∼1000 z ∼ 6 quasars to z {sub AB} < 23, and ∼30 quasars at z > 6.5 to J {sub VEGA} < 19.5.},
doi = {10.3847/1538-4357/AA689F},
journal = {Astrophysical Journal},
number = 1,
volume = 839,
place = {United States},
year = {Mon Apr 10 00:00:00 EDT 2017},
month = {Mon Apr 10 00:00:00 EDT 2017}
}