Journal article
CLOSE COMPANIONS TO TWO HIGH-REDSHIFT QUASARS
The Astronomical journal, v 148(4), pp 1-12
01 Oct 2014
Abstract
We report the serendipitous discoveries of companion galaxies to two high-redshift quasars. SDSS J025617.7+001904 is a z = 4.79 quasar included in our recent survey of faint quasars in the SDSS Stripe 82 region. The initial MMT slit spectroscopy shows excess Ly alpha emission extending well beyond the quasar's light profile. Further imaging and spectroscopy with LBT/MODS1 confirms the presence of a bright galaxy (i(AB) = 23.6) located 2 '' (12 kpc projected) from the quasar with strong Ly alpha emission (EW0 approximate to 100 angstrom) at the redshift of the quasar, as well as faint continuum. The second quasar, CFHQS J005006.6+344522 (z = 6.25), is included in our recent HST SNAP survey of z similar to 6 quasars searching for evidence of gravitational lensing. Deep imaging with ACS and WFC3 confirms an optical dropout similar to 4.5 mag fainter than the quasar (Y-AB = 25) at a separation of 0 ''.9. The red i(775)-Y-105 color of the galaxy and its proximity to the quasar (5 kpc projected if at the quasar redshift) strongly favor an association with the quasar. Although it is much fainter than the quasar, it is remarkably bright when compared to field galaxies at this redshift, while showing no evidence for lensing. Both systems may represent late-stage mergers of two massive galaxies, with the observed light for one dominated by powerful ongoing star formation and for the other by rapid black hole growth. Observations of close companions are rare; if major mergers are primarily responsible for high-redshift quasar fueling then the phase when progenitor galaxies can be observed as bright companions is relatively short.
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Details
- Title
- CLOSE COMPANIONS TO TWO HIGH-REDSHIFT QUASARS
- Creators
- Ian D. McGreer - University of ArizonaXiaohui Fan - University of ArizonaMichael A. Strauss - Princeton UniversityZoltan Haiman - Columbia UniversityGordon T. Richards - Drexel UniversityLinhua Jiang - Arizona State UniversityFuyan Bian - Australian National UniversityDonald P. Schneider - Pennsylvania State University
- Publication Details
- The Astronomical journal, v 148(4), pp 1-12
- Publisher
- Iop Publishing Ltd
- Number of pages
- 12
- Grant note
- NSF Telescope System Instrumentation Program (TSIP) 1107682 / Division Of Astronomical Sciences; National Science Foundation (NSF); NSF - Directorate for Mathematical & Physical Sciences (MPS) 12184; 12493; NAS 5-26555 / Space Telescope Science Institute under NASA; Space Telescope Science Institute Ohio Board of Regents Ohio State University Office of Research; Ohio State University AST 08-06861; AST 11-07682; AST-9987045 / NSF; National Science Foundation (NSF)
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000342233400015
- Scopus ID
- 2-s2.0-84907196556
- Other Identifier
- 991019168314404721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Astronomy & Astrophysics