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 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:
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FileName Lrecl Records Explanations
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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
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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
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Bytes Format Units Label Explanations
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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
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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.
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Byte-by-byte Description of file: table[345].dat
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Bytes Format Units Label Explanations
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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)
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Note (1): The background and foreground quasars are labeled A and B,
respectively
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Jul-2008