MUSE observations towards the lensing cluster A2744: Intersection between the LBG and LAE populations at z ∼ 3–7

Abstract

We present a study of the intersection between the populations of star forming galaxies selected as either Lyman break galaxies (LBGs) or Lyman-alpha emitters (LAEs) in the redshift range 2.9 − 6.7 and within the same volume of universe sampled by the Multi-Unit Spectroscopic Explorer (MUSE) behind the Hubble Frontier Fields lensing cluster A2744. We define three samples of star-forming galaxies: LBG galaxies with an LAE counterpart (92 galaxies), LBG galaxies without an LAE counterpart (408 galaxies), and LAE galaxies without an LBG counterpart (46 galaxies). All these galaxies are intrinsically faint because of the lensing nature of the sample (M1500 ≥ −20.5). The fraction of LAEs among all selected star-forming galaxies increases with redshift up to z ∼ 6 and decreases for higher redshifts, in agreement with previous findings. The evolution of LAE/LBG populations with UV magnitude and Lyα luminosity shows that the LAE selection is able to identify intrinsically UV faint galaxies with M1500 ≥ −15 that are typically missed in the deepest lensing photometric surveys. The LBG population seems to fairly represent the total population of star-forming galaxies down to M1500 ∼ −15. Galaxies with M1500 < −17 tend to have SFRLyα < SFRuv, whereas the opposite trend is observed within our sample for faint galaxies with M1500 > −17, including galaxies only detected by their Lyα emission, with a large scatter. These trends, previously observed in other samples of star-forming galaxies at high-z, are seen here for very faint M1500 ∼ −15 galaxies; that is, much fainter than in previous studies. The present results show no clear evidence for an intrinsic difference between the properties of the two populations selected as LBG and/or LAE. The observed trends could be explained by a combination of several phenomena, like the existence of different star-formation regimes, the dust content, the relative distribution and morphology of dust and stars, or the stellar populations.

An Hα Impression of Lyα Galaxies at z ≃ 6 with Deep JWST/NIRCam Imaging

“…The rest of them are Lymanbreak galaxies (LBGs) selected by the dropout technique and identified by Lyα lines (e.g., Steidel et al 1996;Jones et al 2012;Inami et al 2017;Pentericci et al 2018). The LAEs and LBGs (with Lyα lines) are probably indistinguishable in terms of their intrinsic properties such as age, stellar mass, and star formation rate (SFR; e.g., Dayal & Ferrara 2012;Jiang et al 2016;de La Vieuville et al 2020). We thus call both of them Lyα galaxies in the following text.…”

The Origin of the Observed Lyman alpha EW Distribution of Dwarf Galaxies at z~2

“…But in order to measure the attenuation, one must first know the intrinsic distribution of EW Ly𝛼 to compare with the observed distribution. The evolution of the EW Ly𝛼 distribution has been used to study the end of reionization and is well understood from z= 3 − 6 and for "bright" galaxies with absolute UV magnitudes M UV < −19 (Stark et al 2010(Stark et al , 2011Pentericci et al 2011;Curtis-Lake et al 2012;Ono et al 2012;Schenker et al 2012;Cassata et al 2015;De Barros et al 2017;Haro et al 2018;Caruana et al 2018;Fuller et al 2020;De La Vieuville et al 2020;Kusakabe et al 2020;Zhang et al 2021). At 𝑧 = 2 there has been some study of the brighter star-forming galaxies (M UV < −19) (Reddy & Steidel 2009;Cassata et al 2015;Hathi et al 2016;Du et al 2021;Zhang et al 2021), but little work has been done to study the fainter population (M UV > −19).…”

Probing the Diffuse Lyman-alpha Emission on Cosmological Scales: Lyα Emission Intensity Mapping Using the Complete SDSS-IV eBOSS Survey

“…A large portion of LBGs exhibit Lyα emission, though their rest-frame equivalent width (REW) might not satisfy the criteria for LAE selections (Shapley et al 2003;de La Vieuville et al 2020) if measured with a typical aperture of 2 in diameter in NB surveys. It is also detected in deep stacks of luminous and massive LBGs (Steidel et al 2011) and in individual UV-selected galaxies in recent MUSE eXtremely Deep Field (MXDF) observations (Kusakabe et al 2022).…”