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J/ApJ/651/61    Optically thick absorbers near luminous quasars (Hennawi+, 2006)

Quasars probing quasars. I. Optically thick absorbers near luminous quasars. Hennawi J.F., Prochaska J.X., Burles S., Strauss M.A., Richards G.T., Schlegel D.J., Fan X., Schneider D.P., Zakamska N.L., Oguri M., Gunn J.E., Lupton R.H., Brinkmann J. <Astrophys. J., 651, 61-83 (2006)> =2006ApJ...651...61H
ADC_Keywords: QSOs ; Redshifts ; Photometry, SDSS Keywords: cosmology: observations - cosmology: theory - intergalactic medium - quasars: absorption lines - quasars: general - surveys Abstract: With close pairs of quasars at different redshifts, a background quasar sight line can be used to study a foreground quasar's environment in absorption. We search 149 moderate-resolution background quasar spectra from Gemini, Keck, the MMT, and the SDSS to survey Lyman limit systems (LLSs) and damped Lyα systems (DLAs) in the vicinity of 1.8<z<4.0 luminous foreground quasars. A sample of 27 new quasar-absorber pairs is uncovered with column densities 1017.2cm-2<NH<1020.9cm-2 and transverse (proper) distances of 22h-1kpc<R<1.7h-1Mpc from the foreground quasars. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 97 28 Optically thick absorption-line systems near foreground quasars table2.dat 97 7 Tentative optically thick absorption-line systems near foreground quasars table3.dat 91 54 Coordinates and photometry for projected quasar pairs in table 1 table4.dat 91 12 Coordinates and photometry for projected quasar pairs in table 2 table5.dat 91 5 Coordinates and photometry for the five quasars in the projected group SDSS J0127+1507
See also: II/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2007) http://www.sdss.org : SDSS Home Page Byte-by-byte Description of file: table1.dat table2.dat
Bytes Format Units Label Explanations
1- 15 A15 --- System System name (SDSS JHHMM+DDMM) 16 A1 --- n_System [a-d] Note on System (1) 18- 21 F4.2 --- zbg Background quasar redshift 23- 27 F5.3 --- zfg Foreground quasar redshift 29- 33 F5.1 arcsec Dthe Angular separation of the quasar pair sight lines (2) 35- 38 I4 kpc R Radius (in (h-1kpc) 40- 45 F6.4 --- zabs Absorber redshift 47- 50 I4 km/s |DV| Velocity difference between the absorber redshift and our best estimate of the redshift of the foreground quasar 52- 55 I4 km/s DVfg Estimated error on the foreground quasar redshift 57 A1 --- l_logNHI Limit flag on logNHI 58- 62 F5.2 [cm-2] logNHI ? Column density of the absorber from our fit to the HI profile 64- 67 F4.2 [cm-2] e_logNHI ? rms uncertainty on logNHI 69- 72 I4 --- gUV Maximum enhancement of the quasar's ionizing photon flux over that of the extragalactic ionizing background, at the location of the background quasar sight line, assuming that gUV=1+FQSO/FUVB the quasar emission is isotropic 74- 82 A9 --- n_zfg Emission line that was centered to determine foreground quasar redshift (zfg) 84- 89 A6 --- obs.fg Instrument used to observed foreground quasar 92- 97 A6 --- obs.bg Instrument used to observed background quasar
Note (1): Individual notes as follows: a = In the systems SDSS J0127+1507 there are two distinct background quasars at z=2.38 and 2.60, which show absorption in the vicinity of the same foreground quasar at z=1.818. b = The foreground quasar for this system has large BAL troughs in the Lyα and CIV emission lines. The redshift was computed by comparing the peak of CIV, determined by eye, to the shifted wavelength lambda=1545.3Å We apply a conservative redshift uncertainty of ±1500km/s. c = In the systems SDSS J2347+1501, there is a single background quasar at z=2.29 and two foreground quasars at z=2.157 and 2.167, although the velocity separation is larger than our nominal 1500km/s cutoff for the former. d = Voigt profile fits to the Lyα absorption in the SDSS spectrum of the background quasar gave log(NHI)=19.55±0.3. An archive echelle spectrum of this quasar gives the smaller value that is listed in the table, logNHI=18.8+.-0.2. Note (2): The angular separation of the quasar pair sight lines corresponds to a transverse proper separation of R at the foreground quasar redshift.
Byte-by-byte Description of file: table[345].dat
Bytes Format Units Label Explanations
1- 15 A15 --- Name Quasar name (SDSS JHHMM+DDMM or 2QZ JHHMM+DDMM) 16 A1 --- m_Name [A-E] Multiplicity index on Name (1) 18- 19 I2 h RAh Right ascension (J2000) 21- 22 I2 min RAm Right ascension (J2000) 24- 28 F5.2 s RAs Right ascension (J2000) 30 A1 --- DE- Declination sign (J2000) 31- 32 I2 deg DEd Declination (J2000) 34- 35 I2 arcmin DEm Declination (J2000) 37- 40 F4.1 arcsec DEs Declination (J2000) 42- 45 F4.2 --- z Spectroscopic redshift 47- 51 F5.2 mag umag Extinction-corrected SDSS u magnitude 53- 57 F5.2 mag gmag Extinction-corrected SDSS g magnitude 59- 63 F5.2 mag rmag Extinction-corrected SDSS r magnitude 65- 69 F5.2 mag imag Extinction-corrected SDSS i magnitude 71- 75 F5.2 mag zmag Extinction-corrected SDSS z magnitude 77- 91 A15 --- System System name ((SDSS JHHMM+DDMM)
Note (1): The background and foreground quasars are labeled A and B, respectively
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Jul-2008
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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