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J/ApJ/719/1672     SDSS binary quasars at high redshift. I.     (Hennawi+, 2010)

Binary quasars at high redshift. I. 24 new quasar pairs at z ∼ 3-4. Hennawi J.F., Myers A.D., Shen Y., Strauss M.A., Djorgovski S.G., Fan X., Glikman E., Mahabal A., Martin C.L., Richards G.T., Schneider D.P., Shankar F. <Astrophys. J., 719, 1672-1692 (2010)> =2010ApJ...719.1672H
ADC_Keywords: QSOs ; Photometry, SDSS ; Spectroscopy ; Redshifts Keywords: cosmology: observations - large-scale structure of universe - quasars: general - surveys Abstract: The clustering of quasars on small scales yields fundamental constraints on models of quasar evolution and the buildup of supermassive black holes. This paper describes the first systematic survey to discover high-redshift binary quasars. Using color-selection and photometric redshift techniques, we searched 8142deg2 of Sloan Digital Sky Survey imaging data for binary quasar candidates, and confirmed them with follow-up spectroscopy. Our sample of 27 high-redshift binaries (24 of them new discoveries) at redshifts 2.9<z<4.3 with proper transverse separations 10kpc<RT<650kpc increases the number of such objects known by an order of magnitude. Eight members of this sample are very close pairs with RT<100kpc, and of these close systems four are at z>3.5. The completeness and efficiency of our well-defined selection algorithm are quantified using simulated photometry and we find that our sample is ∼50% complete. Description: Discovery spectra of our binary candidates were obtained with the Astrophysical Research Consortium 3.5m telescope at the Apache Point Observatory (APO), the 6.5m Multiple Mirror Telescope (MMT), the Palomar 200 inch telescope, the Mayall 4m telescope at Kitt Peak National Observatory, and the KeckII 10m telescope from 2005 November to 2008 June. Table 3 lists relevant quantities for a total of 27 binaries in the SDSS imaging area footprint, including three previously known pairs. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 111 54 High-redshift binary quasars in the SDSS imaging footprint
See also: VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010) J/ApJ/678/635 : Spectroscopy of quasar binary candidates (Myers+, 2008) J/AJ/131/1 : Binary quasars in the SDSS (Hennawi+, 2006) : SDSS home page Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 16 A16 --- [HMS2010] Brighter quasar designation (SDSS JHHMM+DDMMA or PSS JHHMM+DDMMA) (1) 18 A1 --- f_[HMS2010] [a] PSS quasar (2) 20- 21 I2 h RAh Hour of right ascension (J2000) 23- 24 I2 min RAm Minute of right ascension (J2000) 26- 31 F6.3 s RAs Second of right ascension (J2000) 33 A1 --- DE- Sign of declination (J2000) 34- 35 I2 deg DEd Degree of declination (J2000) 37- 38 I2 arcmin DEm Arcminute of declination (J2000) 40- 44 F5.2 arcsec DEs Arcsecond of declination (J2000) 46- 50 F5.2 mag umag ? SDSS u-band magnitude (3) 52- 56 F5.2 mag gmag ? SDSS g-band magnitude (3) 58 A1 --- u_rmag [~] Uncertainty flag on rmag 59- 63 F5.2 mag rmag ? SDSS r-band magnitude (3) 65- 69 F5.2 mag imag ? SDSS i-band magnitude (3) 71- 75 F5.2 mag zmag ? SDSS z-band magnitude (3) 77- 81 F5.1 --- chi2s ? The minimum stellar locus distance (χ2star) 83- 86 F4.1 --- chi2p ? Quasar locus distance (χ2phot) 88- 92 F5.3 --- z Redshift 94- 97 I4 km/s e_z Estimation of the redshift uncertainty 99-102 I4 km/s DelV ? Velocity difference ΔV between the two members of a pair (primary only) 104-107 F4.1 arcsec DelT ? Angular separation Δθ 109-111 I3 kpc RT ? Transverse proper separation
Note (1): The brightest member of the pair in the i band is always labeled "A" and the fainter member is labeled "B."; see Note (2) for the PSS designation. Note (2): a = This quasar pair was selected via a different method during a pilot search for proto-clusters associated with z>4 quasars (see Section 4.1). The redshifts quoted are approximate and we did not measure a velocity difference. The fainter quasar PSS 1315+2924B is not detected in the SDSS imaging, its quoted r-band magnitude is an estimate from Keck LRIS R-band imaging. Note (3): Extinction-corrected SDSS five-band point-spread function (PSF) photometry is given in the columns umag, gmag, rmag, imag, and zmag.
History: From electronic version of the journal
(End) Emmanuelle Perret [CDS] 19-Jun-2012
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