2 research outputs found
Evolution of the Lyman-{\alpha} emitting fraction and UV properties of lensed star-forming galaxies between 2.9 < z < 6.7
Faint galaxies are theorised to have played a major role in reionising the
Universe. Their properties as well as the Lyman-{\alpha} emitter fraction,
could provide useful insight into this epoch. We use four galaxy clusters from
the Lensed Lyman-alpha MUSE Arcs Sample (LLAMAS) which also have deep HST
photometry to select a population of intrinsically faint Lyman Break Galaxies
(LBGs) and Lyman-alpha Emitters (LAEs). We study the interrelation of these two
populations, their properties, and the fraction of LBGs that display
Lyman-alpha emission. The use of lensing clusters allows us to access an
intrinsically faint population, the largest sample collected for this purpose:
263 LAEs and 972 LBGs between redshifts of 2.9 and 6.7, Lyman-alpha
luminosities between 39.5 < log(L)(erg/s) < 42 and absolute UV magnitudes
between -22 < M1500 < -12. We find a redshift evolution of the Lyman-alpha
emitter fraction in line with past results, with diminished values above z = 6,
taken to signify an increasingly neutral intervening IGM. Inspecting this
redshift evolution with different limits on Lyman-alpha equivalent width (EW)
and M1500 we find that the Lyman-alpha emitter fraction for the UV-brighter
half of our sample is higher than the fraction for the UV-fainter half, a
difference which increases at higher redshift. This is a surprising result and
can be interpreted as a population of low Lyman-alpha EW, UV-bright galaxies
situated in reionised bubbles. This result is especially interesting in the
context of similar, UV-bright, low Lyman-alpha EW objects recently detected
around the epoch of reionisation. We extend to intrinsically fainter objects
the previously observed trends of LAEs among LBGs as galaxies with high
star-formation rates and low dust content, as well as the strongest LAEs having
in general fainter UV magnitudes and steeper UV slopes.Comment: 14 pages, 10 figures, accepted in A&
Probing the faint end Luminosity Function of Lyman Alpha Emitters at 3<z<7 behind 17 MUSE lensing clusters
We present a study of the galaxy Lyman-alpha luminosity function (LF) using a
sample of 17 lensing clusters observed by the MUSE/VLT. Magnification from
strong gravitational lensing by clusters of galaxies and MUSE apabilities allow
us to blindly detect LAEs without any photometric pre-selection, reaching the
faint luminosity regime. 600 lensed LAEs were selected behind these clusters in
the redshift range 2.9<< 6.7, covering four orders of magnitude in
magnification-corrected Lyman-alpha luminosity (39.0<log< 43.0). The method
used in this work () follows the recipes originally developed
by arXiv:1905.13696(N) (DLV19) with some improvements to better account for the
effects of lensing when computing the effective volume. The total co-moving
volume at 2.9<<6.7 is 50 . Our LF points in the bright
end (log L)>42 are consistent with those obtained from blank field
observations. In the faint luminosity regime, the density of sources is well
described by a steep slope, for the global redshift range. Up to
log(L)41, the steepening of the faint end slope with redshift, suggested
by the earlier work of DLV19 is observed, but the uncertainties remain large. A
significant flattening is observed towards the faintest end, for the highest
redshift bins (log<41). Using face values, the steep slope at the faint-end
causes the SFRD to dramatically increase with redshift, implying that LAEs
could play a major role in the process of cosmic reionization. The flattening
observed towards the faint end for the highest redshift bins still needs
further investigation. This turnover is similar to the one observed for the UV
LF at in lensing clusters, with the same conclusions regarding the
reliability of current results (e.g.arXiv:1803.09747(N); arXiv:2205.11526(N)).Comment: 20 pages, 15 figures, 6 tables. Accepted for publication in A\&