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1491. Lyman alpha forest in HE 0515-4414
ID:
ivo://CDS.VizieR/J/A+A/391/L11
Title:
Lyman alpha forest in HE 0515-4414
Short Name:
J/A+A/391/L11
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigated HST/STIS and VLT/UVES spectra of the bright QSO HE 0515-4414 (z_em_=1.73, B=15.0) to study the Lyman alpha forest in the redshift range 0.9 < z < 1.7 at a resolution <10km/s.
1492. Lyman alpha forest of 55 QSOs
ID:
ivo://CDS.VizieR/J/ApJ/662/72
Title:
Lyman alpha forest of 55 QSOs
Short Name:
J/ApJ/662/72
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examine the evolution of the IGM Ly{alpha} optical depth distribution using the transmitted flux probability distribution function (PDF) in a high-resolution sample of 55 QSOs spanning absorption redshifts 1.7<z<5.8. The data are compared to two theoretical {tau} distributions: a model distribution based on the density distribution of Miralda-Escude et al. (2000ApJ...530....1M; MHR00) and a lognormal distribution.
1493. Lyman-Alpha Forest of 3 QSOs
ID:
ivo://CDS.VizieR/J/A+A/373/757
Title:
Lyman-Alpha Forest of 3 QSOs
Short Name:
J/A+A/373/757
Date:
21 Oct 2021
Publisher:
CDS
Description:
The line tables, tablea1.dat, tablea2.dat and tablea3.dat, list the fitted line parameters from Voigt-profile fitting of the Lyman-alpha forest clouds: redshift, z, the Doppler parameter, b, and its density, N. The profile fitting was done with the program VPFIT. The three QSOs, HE0515-4414, J2233-606 and HE2217-2818 were taken with VLT/UVES with a resolution of 45,000 and S/N of 30-50 in the forest regions.
1494. Lyman-alpha forest toward PKS 0405-123
ID:
ivo://CDS.VizieR/J/ApJ/636/631
Title:
Lyman-alpha forest toward PKS 0405-123
Short Name:
J/ApJ/636/631
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results for Ly{alpha} forest and metal absorbers from ~7km/s resolution Space Telescope Imaging Spectrograph (STIS) data for QSO PKS 0405-123 (z=0.574). We analyze strong and weak samples of Ly{alpha} forest lines, containing 60 absorbers with column density log N(HI)>=13.3 over 0.002<z<0.423 and 44 with logN(HI)>=13.1 over 0.020<z<0.234, respectively.
1495. 237 Lyman-alpha spectra of MUSE-Wide survey
ID:
ivo://CDS.VizieR/J/A+A/608/A139
Title:
237 Lyman-alpha spectra of MUSE-Wide survey
Short Name:
J/A+A/608/A139
Date:
21 Oct 2021
Publisher:
CDS
Description:
We compare 237 Lyman-{alpha} (Ly{alpha}) spectra of the "MUSE-Wide survey" (Herenz et al., 2017, Cat. J/A+A/606/A12) to a suite of radiative transfer simulations consisting of a central luminous source within a concentric, moving shell of neutral gas, and dust. This six parameter shell-model has been used numerously in previous studies, however, on significantly smaller data-sets. We find that the shell-model can reproduce the observed spectral shape very well - better than the also common 'Gaussian-minus-Gaussian' model which we also fitted to the dataset. Specifically, we find that ~94% of the fits possess a goodness-of-fit value of p(chi^2^)>0.1. The large number of spectra allows us to robustly characterize the shell-model parameter range, and consequently, the spectral shapes typical for realistic spectra. We find that the vast majority of the Ly{alpha} spectral shapes require an outflow and only ~5% are well-fitted through an inflowing shell. In addition, we find ~46% of the spectra to be consistent with a neutral hydrogen column density <10^17^cm^-2^ -- suggestive of a non-negligible fraction of continuum leakers in the MUSE-Wide sample. Furthermore, we correlate the spectral against the Ly{alpha} halo properties against each other but do not find any strong correlation.
1496. Lyman and Werner molecular hydrogen transitions
ID:
ivo://CDS.VizieR/J/MNRAS/403/1541
Title:
Lyman and Werner molecular hydrogen transitions
Short Name:
J/MNRAS/403/1541
Date:
21 Oct 2021
Publisher:
CDS
Description:
Molecular transitions recently discovered at redshift z_abs_=2.059 towards the bright background quasar J2123-0050 are analysed to limit cosmological variation in the proton-to-electron mass ratio, {mu}=mp/me. Observed with the Keck telescope, the optical echelle spectrum has the highest resolving power and largest number (86) of H_2_ transitions in such analyses so far. Also, (seven) HD transitions are used for the first time to constrain {mu}-variation.
1497. Lyman-break galaxies and LAEs at z~3
ID:
ivo://CDS.VizieR/J/ApJ/765/47
Title:
Lyman-break galaxies and LAEs at z~3
Short Name:
J/ApJ/765/47
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the contribution of star-forming galaxies to the ionizing background at z~3, building on previous work based on narrowband (NB3640) imaging in the SSA22a field. We use new Keck/LRIS spectra of Lyman break galaxies (LBGs) and narrowband-selected Ly{alpha} emitters (LAEs) to measure redshifts for 16 LBGs and 87 LAEs at z>3.055, such that our NB3640 imaging probes the Lyman-continuum (LyC) region. When we include the existing set of spectroscopically confirmed LBGs, our total sample with z>3.055 consists of 41 LBGs and 91 LAEs, of which 9 LBGs and 20 LAEs are detected in our NB3640 image. With our combined imaging and spectroscopic data sets, we critically investigate the origin of NB3640 emission for detected LBGs and LAEs. We remove from our samples three LBGs and three LAEs with spectroscopic evidence of contamination of their NB3640 flux by foreground galaxies and statistically model the effects of additional, unidentified foreground contaminants. The resulting contamination and LyC-detection rates, respectively, are 62%+/-13% and 8%+/-3% for our LBG sample, and 47%+/-10% and 12%+/-2% for our LAE sample. The corresponding ratios of non-ionizing UV to LyC flux density, corrected for intergalactic medium (IGM) attenuation, are 18.0^+34.8^_-7.4_ for LBGs and 3.7^+2.5^_-1.1_ for LAEs. We use these ratios to estimate the total contribution of star-forming galaxies to the ionizing background and the hydrogen photoionization rate in the IGM, finding values larger than, but consistent with, those measured in the Ly{alpha} forest. Finally, the measured UV to LyC flux-density ratios imply model-dependent LyC escape fractions of f^LyC^_esc_~5%-7% for our LBG sample and f^LyC^_esc_~10%-30% for our fainter LAE sample.
1498. Lyman break galaxies at z~1.8-2.8
ID:
ivo://CDS.VizieR/J/ApJ/697/1410
Title:
Lyman break galaxies at z~1.8-2.8
Short Name:
J/ApJ/697/1410
Date:
21 Oct 2021
Publisher:
CDS
Description:
A photometric sample of ~8000 V<25.3 candidate Lyman break galaxies (LBGs) has been selected by combining Subaru/Suprime-Cam BVRCi'z' optical data with deep GALEX/NUV imaging of the Subaru Deep Field. Follow-up spectroscopy confirmed 24 LBGs at 1.5<~z<~2.7. Among the optical spectra, 12 have Ly{alpha} emission with rest-frame equivalent widths of ~5-60{AA}. The success rate for identifying LBGs as NUV-dropouts at 1.5<z<2.7 is 86%. The rest-frame UV (1700{AA}) luminosity function (LF) is constructed from the photometric sample with corrections for stellar contamination and z<1.5 interlopers (lower limits). The LF is 1.7+/-0.1 (1.4+/-0.1 with a hard upper limit on stellar contamination) times higher than those of z~2 BXs and z~3 LBGs.
1499. Lyman-break galaxies at z {>~} 4
ID:
ivo://CDS.VizieR/J/ApJ/519/1
Title:
Lyman-break galaxies at z {>~} 4
Short Name:
J/ApJ/519/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present initial results of a survey for star-forming galaxies in the redshift range 3.8{<~}z{<~}4.5. This sample consists of a photometric catalog of 244 galaxies culled from a total solid angle of 0.23 deg^2^ to an apparent magnitude of I_AB_=25.0. Spectroscopic redshifts in the range 3.61{<~}z{<~}4.81 have been obtained for 48 of these galaxies; their median redshift is <z>=4.13. Selecting these galaxies in a manner entirely analogous to our large survey for Lyman-break galaxies at smaller redshift (2.7{<~}z{<~}3.4) allows a relatively clean differential comparison between the populations and integrated luminosity density at these two cosmic epochs. Over the same range of UV luminosity, the spectroscopic properties of the galaxy samples at z{~}4 and z{~}3 are indistinguishable, as are the luminosity function shapes and the total integrated UV luminosity densities [{rho}_UV_(z=3)/{rho}_UV_(z=4)=1.1{+/_}0.3].
1500. Lyman cont. luminosity of SDSS quasar pairs at z~3
ID:
ivo://CDS.VizieR/J/ApJ/884/151
Title:
Lyman cont. luminosity of SDSS quasar pairs at z~3
Short Name:
J/ApJ/884/151
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used spectra of 181 projected quasar pairs at separations <=1.5' from the Sloan Digital Sky Survey Data Release 12 in the redshift range of 2.5-3.5 to probe the proximity regions of the foreground quasars. We study the proximity effect both in the longitudinal and in the transverse directions, by carrying out a comparison of the Ly{alpha} absorption lines originating from the vicinity of quasars to those originating from the general intergalactic medium at the same redshift. We found an enhancement in the transmitted flux within 4Mpc to the quasar in the longitudinal direction. However, the trend is found to be reversed in the transverse direction. In the longitudinal direction, we derived an excess overdensity profile showing an excess up to r<=5Mpc after correcting for the quasar's ionization, taking into account the effect of low spectral resolution. This excess overdensity profile matches with the average overdensity profile in the transverse direction without applying any correction for the effect of the quasar's ionization. Among various possible interpretations, we found that the anisotropic obscuration of the quasar's ionization seems to be the most probable explanation. This is also supported by the fact that all of our foreground quasars happen to be type 1 AGNs. Finally, we constrain the average quasar's illumination along the transverse direction as compared to that along the longitudinal direction to be <=27% (3{sigma} confidence level).

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