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3751. Ly{alpha} emitters near B3 J2330+3927
ID:
ivo://CDS.VizieR/J/MNRAS/400/L66
Title:
Ly{alpha} emitters near B3 J2330+3927
Short Name:
J/MNRAS/400/L66
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discovery of a candidate of giant radio-quiet Ly{alpha} blob (RQLAB) in a large-scale structure around a high-redshift radio galaxy (HzRG) lying in a giant Ly{alpha} halo B3 J2330+3927 at redshift z=3.087. We obtained narrow- and broad-band imaging around B3 J2330+3927 with Subaru/Suprime-Cam to search for Ly{alpha} emitters (LAEs) and absorbers (LAAs) at redshift z=3.09+/-0.03. We detected candidate 127 LAEs and 26 LAAs in the field of view of 31x24arcmin^2^ (58x44 comoving Mpc).
3752. LY And photometric followup
ID:
ivo://CDS.VizieR/J/other/NewA/51.59
Title:
LY And photometric followup
Short Name:
J/other/NewA/51.
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a low-dispersion spectrum and two sets of CCD photometric light curves of the eclipsing binary LY And for the first time. The spectrum of LY And was classified as G2. We derived an updated ephemeris based on all previously available and our newly acquired minimum light times. Our analyses of LY And light curve minimum times reveals that the differences between calculated and observed minimum times for LY And can be represented by an upward parabolic curve, which means its orbital period is increasing with a rate of 1.88 (+/-0.13)x10^-7^days/year. This increase in orbital period may be interpreted as mass transfer from the primary component to the secondary component, with a rate of dM1/dt=-4.54x10^-8^M_{sun}_/year. By analyzing our CCD photometric light curves obtained in 2015, we obtained its photometric solution with the Wilson-Devinney program. This photometric solution also fits very well our light curves obtained in 2014. Our photometric solution shows that LY And is a contact eclipsing binary and its contact factor is f=(17.8+/-1.9)%. Furthermore, both our spectroscopic and photometric data show no obvious chromospheric activity of LY And.
3753. Lyman-{alpha} emitters from redshifts z~2-3
ID:
ivo://CDS.VizieR/J/A+A/498/13
Title:
Lyman-{alpha} emitters from redshifts z~2-3
Short Name:
J/A+A/498/13
Date:
21 Oct 2021
Publisher:
CDS
Description:
Narrow-band surveys to detect Ly{alpha} emitters are powerful tools for identifying high, and very high, redshift galaxies. Although samples are increasing at redshifts z=3-6, the nature of these galaxies is still poorly known. The number of galaxies detected at redshifts below z~3 are also small. We study the properties of z=2.25 Ly{alpha} emitters and compare them with those of z>3 Ly{alpha} emitters We present narrow-band imaging made with the MPG/ESO 2.2m telescope and the WFI (Wide Field Imager) detector. Using this data, we have searched for emission-line objects. We find 170 candidate typical Ly{alpha} emitters and 17 candidates that we regard as high UV-transmission Ly{alpha} emitters. We have derived the magnitudes of these objects in 8 photometric bands from u* to K_s_, and studied whether they have X-ray and/or radio counterparts.
3754. Lyman break galaxies and LAEs HST photometry
ID:
ivo://CDS.VizieR/J/ApJ/810/107
Title:
Lyman break galaxies and LAEs HST photometry
Short Name:
J/ApJ/810/107
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present U_336_V_606_J_125_H_160_ follow-up Hubble Space Telescope (HST) observations of 16 z~3 candidate Lyman continuum (LyC) emitters in the HS1549+1919 field. With these data, we obtain high spatial-resolution photometric redshifts of all sub-arcsecond components of the LyC candidates in order to eliminate foreground contamination and identify robust candidates for leaking LyC emission. Of the 16 candidates, we find one object with a robust LyC detection that is not due to foreground contamination. This object (MD5) resolves into two components; we refer to the LyC-emitting component as MD5b. MD5b has an observed 1500 {AA} to 900 {AA} flux-density ratio of (F_UV_/F_LyC_)_obs_=4.0+/-2.0, compatible with predictions from stellar population synthesis models. Assuming minimal IGM absorption, this ratio corresponds to a relative (absolute) escape fraction of f_esc,rel_^MD5b^=75%-100% (f_esc,abs_^MD5b^=14%-19%). The stellar population fit to MD5b indicates an age of <~50 Myr, which is in the youngest 10% of the HST sample and the youngest third of typical z~3 Lyman break galaxies, and may be a contributing factor to its LyC detection. We obtain a revised, contamination-free estimate for the comoving specific ionizing emissivity at z=2.85, indicating (with large uncertainties) that star-forming galaxies provide roughly the same contribution as QSOs to the ionizing background at this redshift. Our results show that foreground contamination prevents ground-based LyC studies from obtaining a full understanding of LyC emission from z~3 star-forming galaxies. Future progress in direct LyC searches is contingent upon the elimination of foreground contaminants through high spatial-resolution observations, and upon acquisition of sufficiently deep LyC imaging to probe ionizing radiation in high-redshift galaxies.
3755. Lyman break galaxies at redshift z~3
ID:
ivo://CDS.VizieR/J/ApJ/592/728
Title:
Lyman break galaxies at redshift z~3
Short Name:
J/ApJ/592/728
Date:
04 Dec 2021
Publisher:
CDS
Description:
We present the basic data for a large ground-based spectroscopic survey for z~3 Lyman break galaxies (LBGs), photometrically selected using rest-UV colors from very deep images in 17 high Galactic latitude fields. The total survey covers an area of 0.38deg^2^ and includes 2347 photometrically selected candidate LBGs to an apparent {R}_AB_ magnitude limit of 25.5. Approximately half of these objects have been observed spectroscopically using the Keck telescopes, yielding 940 redshifts with <z>=2.96+/-0.29. We discuss the images, photometry, target selection, and spectroscopic program in some detail and present catalogs of the photometric and spectroscopic data, made available in electronic form. We discuss the general utility of conducting nearly volume-limited redshift surveys in prescribed redshift intervals using judicious application of photometric preselection.
3756. 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.
3757. 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].
3758. 48 Lyman break galaxies at z~3 in HUDF
ID:
ivo://CDS.VizieR/J/ApJ/736/48
Title:
48 Lyman break galaxies at z~3 in HUDF
Short Name:
J/ApJ/736/48
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present evidence for spatially extended low surface brightness emission around Lyman break galaxies (LBGs) in the V-band image of the Hubble Ultra Deep Field, corresponding to the z~3 rest-frame far-UV (FUV) light, which is a sensitive measure of star formation rates (SFRs). We find that the covering fraction of molecular gas at z~3 is not adequate to explain the emission in the outskirts of LBGs, while the covering fraction of neutral atomic-dominated hydrogen gas at high redshift is sufficient. We develop a theoretical framework to connect this emission around LBGs to the expected emission from neutral HI gas, i.e., damped Ly{alpha} systems (DLAs), using the Kennicutt-Schmidt (KS) relation. Working under the hypothesis that the observed FUV emission in the outskirts of LBGs is from in situ star formation in atomic-dominated hydrogen gas, the results suggest that the SFR efficiency in such gas at z~3 is between factors of 10 and 50 lower than predictions based on the local KS relation. The total SFR density in atomic-dominated gas at z~3 is constrained to be ~10% of that observed from the inner regions of LBGs. In addition, the metals produced by in situ star formation in the outskirts of LBGs yield metallicities comparable to those of DLAs, which is a possible solution to the "Missing Metals" problem for DLAs. Finally, the atomic-dominated gas in the outskirts of galaxies at both high and low redshifts has similar reduced SFR efficiencies and is consistent with the same power law.
3759. Lyman break galaxies (LBG) at z~1
ID:
ivo://CDS.VizieR/J/MNRAS/431/2080
Title:
Lyman break galaxies (LBG) at z~1
Short Name:
J/MNRAS/431/2080
Date:
21 Oct 2021
Publisher:
CDS
Description:
After carefully cross-identifying previously discovered - and selected by the Galaxy Evolution Explorer (GALEX) - Lyman break galaxy (LBG) candidates one-to-one with their optical counterparts in the field of the Chandra Deep Field South (CDF-S), we re-estimate their photometric redshifts using multiwavelength data from ultraviolet and optical to near-infrared. Considering their re-estimated photometric redshifts and spectral energy distributions, we refine a new updated sample of 383 LBGs at 0.7<~z<~1.4, with two confirmed active galactic nuclei being excluded. There are 260 and 111 LBGs classified as starburst and irregular types, respectively. The ages of the LBGs span from several Myr to 1.5Gyr with a median of ~50Myr. Their dust-corrected star formation rates (SFRs) and stellar masses (M*) are 4-220M_{sun}_/yr and from 2.3x10^8^ to 4x10^11^M_{sun}_, with median values of ~25M_{sun}_/yr and ~10^10^M_{sun}_. The rest-frame far-ultraviolet luminosity function of the LBGs is presented with the best-fitting Schechter parameters of {alpha}=-1.61+/-0.40, M*=-20.40+/-0.22 and {phi}*=(0.89+/-0.30)x10^-3^/Mpc^3^/dex. LBGs of irregular types are mainly distributed along the main sequence of star-forming galaxies, while most LBGs of starburst types are located in the starburst region. Together with previous studies, we suggest that the star formation mode for LBGs at z>3 is mainly starburst, and that it evolves to be more significant to the quenching mode after z~3. A downsizing effect is clearly found, and we discuss the physical implications and comparisons with previous studies in detail. LBGs with larger SFRs are, on average, more compact. In the rest-frame colour (U-B)-M* diagram, LBGs are distributed in the `blue' cloud. We suggest that LBGs might evolve along the blue cloud from later to earlier types. The Hubble Space Telescope images in F606W (V band) and F850LP (z band) are taken from the Galaxy Evolution from Morphology and SEDs (GEMS) survey and the Great Observatories Origins Deep Survey South (GOODS-S) for morphological studies of LBGs. sextractor and galfit are applied in order to obtain their morphological parameters. We establish an image gallery of 277 LBGs, commonly detected in both bands, by visually classifying individual LBGs into the following types: chain, spiral, tadpole, bulge and clump. We define a morphological sample of 142 LBGs with reliable results of Sersic indices and sizes in both bands. We find that LBGs at z~1 are dominated by disc-like galaxies, with median sizes of 2.34 and 2.68kpc in F606W and F850LP, respectively. The correlations between the photometric and morphological properties of LBGs are investigated. Strong correlations between their half-light radii and M* (i.e. size-stellar mass relations) are found in both bands. We discuss the physical connections between the correlations and the downsizing effect.
3760. Lyman-break galaxies (LBG) in the HUDF
ID:
ivo://CDS.VizieR/J/ApJ/703/2033
Title:
Lyman-break galaxies (LBG) in the HUDF
Short Name:
J/ApJ/703/2033
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a sample of 407 z~3 Lyman break galaxies (LBGs) to a limiting isophotal u-band magnitude of 27.6mag in the Hubble Ultra Deep Field. The LBGs are selected using a combination of photometric redshifts and the u-band drop-out technique enabled by the introduction of an extremely deep u-band image obtained with the Keck I telescope and the blue channel of the Low Resolution Imaging Spectrometer. The Keck u-band image, totaling 9hr of integration time, has a 1{sigma} depth of 30.7mag/arcsec^2^, making it one of the most sensitive u-band images ever obtained. The u-band image also substantially improves the accuracy of photometric redshift measurements of ~50% of the z~3 LBGs, significantly reducing the traditional degeneracy of colors between z~3 and z~0.2 galaxies.