J/ApJ/775/78 Lyman limit absorption systems in z∼3 QSOs (Fumagalli+, 2013)
Dissecting the properties of optically thick hydrogen at the peak of cosmic
star formation history.
Fumagalli M., O'Meara J.M., Prochaska J.X., Worseck G.
<Astrophys. J., 775, 78 (2013)>
=2013ApJ...775...78F 2013ApJ...775...78F (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Redshifts ; Spectroscopy
Keywords: cosmology: observations; galaxies: halos; galaxies: high-redshift;
intergalactic medium; quasars: absorption lines
Abstract:
We present the results of a blind survey of Lyman limit systems (LLSs)
detected in absorption against 105 quasars at z∼3 using the blue
sensitive MagE spectrograph at the Magellan Clay telescope. By
searching for Lyman limit absorption in the wavelength range
λ∼3000-4000Å, we measure the number of LLSs per unit
redshift ℓ(z)=1.21±0.28 at z∼2.8. Using a stacking analysis, we
further estimate the mean free path of ionizing photons in the z∼3
universe λmfp912=100±29h70.4-1Mpc. Combined with our
LLS survey, we conclude that systems with logNHI≥17.5/cm2
contribute only ∼40% to the observed mean free path at these
redshifts. Furthermore, with the aid of photoionization modeling, we
infer that a population of ionized and metal poor systems is likely
required to reproduce the metal line strengths observed in a composite
spectrum of 20 LLSs with log NHI∼17.5-19/cm2 at z∼2.6-3.0. Finally,
with a simple toy model, we deduce that gas in the halos of galaxies
can alone account for the totality of LLSs at z≲3, but a
progressively higher contribution from the intergalactic medium is
required beyond z∼3.5. We also show how the weakly evolving number of
LLSs per unit redshift at z≲3 can be modeled either by requiring that
the spatial extent of the circumgalactic medium is redshift invariant
in the last ∼10Gyr of cosmic evolution or by postulating that LLSs
arise in halos that are rare fluctuations in the density field at each
redshift.
Description:
We have observed 105 quasars at zqso∼3.0±0.2 using the MagE
echellette spectrograph (R∼4100) at the Magellan Clay telescope.
Observations have been conducted between the year 2009 and the year
2012, as detailed in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 92 105 Logbook of the observations conducted with
the MagE spectrograph
table2.dat 49 105 Results of the τ≥2 Lyman limit system (LLS)
survey
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See also:
VII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)
VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)
J/MNRAS/435/482 : DLA system from SDSS DR5 (Jorgenson+, 2013)
J/ApJ/770/138 : Metallicities of Lyman limit systems and DLA (Lehner+, 2013)
J/ApJ/765/137 : HST survey for Lyman limit systems. II. (O'Meara+, 2013)
J/ApJ/762/L19 : Quasar pairs spectroscopy (Prochaska+, 2013)
J/ApJ/755/89 : Metallicities of damped Lyα systems (Rafelski+, 2012)
J/ApJ/740/91 : Lyα & OVI in galaxies around quasars (Prochaska+, 2011)
J/ApJ/736/42 : HST QSO Catalog (Ribaudo+, 2011)
J/A+A/530/A50 : Principal Component Analysis of QSO UV spectra (Paris+, 2011)
J/ApJ/728/23 : GALEX UV-bright high-redshift quasars (Worseck+, 2011)
J/ApJ/724/L176 : MgII absorbing gas around galaxies (Chen+, 2010)
J/ApJ/718/392 : SDSS Lyman limit systems at z∼3.5 (Prochaska+, 2010)
J/ApJ/648/L97 : SDSS QSOs supersolar super-LLS (Prochaska+ 2006)
J/MNRAS/354/L31 : SDSS DR2 QSO and DLA properties (Murphy+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name QSO designation
17- 18 I2 h RAh Hour of right ascension (J2000)
20- 21 I2 min RAm Minute of right ascension (J2000)
23- 27 F5.2 s RAs Second of right ascension (J2000)
29 A1 --- DE- Sign of declination (J2000)
30- 31 I2 deg DEd Degree of declination (J2000)
33- 34 I2 arcmin DEm Arcminute of declination (J2000)
36- 39 F4.1 arcsec DEs Arcsecond of declination (J2000)
41- 45 F5.3 --- zqso [2.7/3.4] QSO redshift
47- 51 F5.3 --- e_zqso [0.006/0.02] Statistical error on the quasar
redshift from broad emission lines
53- 55 I3 km/s e_Vel [521/792] Corresponding error on the quasar
redshift in velocity
57- 60 A4 --- n_Name Remark on quasar (G1)
62- 78 A17 --- Date Date(s) of observation (YYMMDD)
80- 83 I4 s Exp [600/5700] Exposure time
85- 87 F3.1 arcsec Slit [0.7] Slit
89- 92 F4.1 --- S/N [6.2/56.7] S/N at 5500Å
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name QSO designation
17- 20 A4 --- n_Name Remark on quasar (G1)
22 I1 --- Src ? Reference (1)
24- 28 F5.3 --- zqso [2.7/3.4] QSO redshift
30- 35 F6.4 --- zstart [2.6/3.4] zstart (2)
37- 42 F6.4 --- zend [2.4/3.3] zend (2)
44- 49 F6.4 --- zlls [0/3.3] LLS redshift (2)
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Note (1): Reference as follows:
1 = included in the survey by Sargent et al. (1989ApJS...69..703S 1989ApJS...69..703S)
2 = included in the survey by Lanzetta (1991ApJ...375....1L 1991ApJ...375....1L)
Note (2): In each sightline, we consider the redshift range
2.6=zend<z<zstart=zqso-z3000km/s. If a τ≥2 LLS is
detected, zend=zlls, and if zlls>zstart, zend=zstart.
See section 5.2.
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Global note:
Note (G1): Note as follows:
C = color selected
NC = non-color selected
B = broad absorption line quasar (visually classified)
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 16-Mar-2015