Context. The Hubble Frontier Fields offer an exceptionally deep window into the high-redshift universe, covering a substantially larger area than the Hubble Ultra-Deep field at low magnification and probing 1-2 mag deeper in exceptional high-magnification regions. This unique parameter space, coupled with the exceptional multi-wavelength ancillary data, can facilitate for useful insights into distant galaxy populations. Aims. We aim to leverage Atacama Large Millimetre Array (ALMA) band 6 (approximate to 263 GHz) mosaics in the central portions of five Frontier Fields to characterize the infrared (IR) properties of 1582 ultraviolet (UV)-selected Lyman-Break Galaxies (LBGs) at redshifts of z similar to 2-8. We investigated individual and stacked fluxes and IR excess (IRX) values of the LBG sample as functions of stellar mass (M-& x22c6;), redshift, UV luminosity and slope beta, and lensing magnification. Methods. LBG samples were derived from color-selection and photometric redshift estimation with Hubble Space Telescope photometry. Spectral energy distributions -templates were fit to obtain luminosities, stellar masses, and star formation rates for the LBG candidates. We obtained individual IR flux and IRX estimates, as well as stacked averages, using both ALMA images and u-v visibilities. Results. Two (2) LBG candidates were individually detected above a significance of 4.1-sigma, while stacked samples of the remaining LBG candidates yielded no significant detections. We investigated our detections and upper limits in the context of the IRX-M-star and IRX-beta relations, probing at least one dex lower in stellar mass than past studies have done. Our upper limits exclude substantial portions of parameter space and they are sufficiently deep in a handful of cases to create mild tension with the typically assumed attenuation and consensus relations. We observe a clear and smooth trend between M-star and beta, which extends to low masses and blue (low) beta values, consistent with expectations from previous works.

We present our measurements of the Ha, [01111, and [OW luminosity functions as part of the Lyman Alpha Galaxies at Epoch of Reionization (LAGER) survey using our samples of 1577 z = 0.47 H a-, 3933 z = 0.93 [0 and 5367 z = 1,59 [0 u1 -selected emission line galaxies in a 3 deg2 single, CHO/Blanco DECam pointing of the COSMOS field, Our observations reach 50- depths of 8.2 x 10-18 erg s -I cm -2 and comoving volumes of (1-7) x 105 Mpc3 making our survey one of the deepest narrow -hand surveys. We select our emission line galaxies via spectroscopic confirmation, photometric redshifts, and colour-colour selections. We measure 316_'_;.`99the observed luminosity functions for each sample and find best fits of (p* = 10-- Mpc-3 and L* = 1041.72"a erg s -I for Ha, (/)* = 1 0-2.161i M c'1 and L* = 1041.38Z6 erg s-1 for [0111], and (/5* = 10 1.971,.i1041.66 'Mpc-3 and L* = erg s -I for [Oil], with a fixed to - 1.75, -1.6, and -1,3, respectively. An excess of bright >1042 erg s -I [0111] emitters is observed and may be due to active galactic nucleus (AGN) contamination, Corrections for dust attenuation are applied assuming Afp, = 1 mag. We also design our own empirical rest frame g - r calibration using SDSS DR12 data, test it against our z = 0,47 H a emitters with zCOSMOS 1D spectra, and calibrate it for (g - r) between -0.8 and 1.3 mag. Dust and AGNcorrected star formation rate densities (SERDs) are measured as logiopsFRAM(.; yr I Mpc-3) = - 1,63 + 0,04, -1.07 + 0,06, and -0.90 + 0.10 for H a, [0 in and [Ou], respectively. We find our [0 uf] and [0 RI samples fully trace cosmic star formation activity at their respective redshifts in comparison to multiwavelength SERDs, while the Ha sample traces =70 per cent of the total z = 0,47 SURD,

The portable adaptive optics (PAO) device is a low-cost and compact system, designed for 4-meter class telescopes that have no adaptive optics (AO) system, because of the physical space limitation at the Nasmyth or Cassegrain focus and the historically high cost of conventional AO. The initial scientific observations of the PAO are focused on the direct imaging of exoplanets and sub-stellar companions. This paper discusses the concept of PAO and the associated high-contrast imaging performance in our recent observational runs. PAO deliver a Strehl ratio better than 60% in H band under median seeing conditions of 1 ''. Combined with our dedicated image rotation and subtraction (IRS) technique and the optimized IRS (O-IRS) algorithm, the averaged contrast ratio for a 5 <= V-mag <= 9 primary star is 1.3 x 10(-5) and 3.3 x 10(-6) at angular distance of 0.36 '' with exposure time of 7 minutes and 2 hours, respectively. PAO has successfully revealed the known exoplanet of kappa And b in our recent observation with the 3.5-meter ARC telescope at Apache Point Observatory. We have performed the associated astrometry and photometry analysis of the recovered kappa And b planet, which gives a projected separation of 0.984 '' +/- 0.05 '', a position angle of 51.1 degrees +/- 0.5 degrees and a mass of 10.15(-1.255)(+2.19) M-Jup. These results demonstrate that PAO can be used for direct imaging of exoplanets with medium-sized telescopes.

We compare the contribution of active galactic nuclei (AGNs) and star formation towards dust heating in sub-mm galaxies (SMGs). We have used ALMA at 0.1-arcsec resolution to image a complete flux-limited sample of seven sub-mm sources previously shown to have spectral energy distributions that were as well-fitted by obscured AGN as star-forming galaxy templates. Indeed, two sub-mm sources were known to be quasars from their absorbed X-ray emission. We find the sub-mm sizes of all SMGs to be small (approximate to 1-2 kpc) and generally similar to 3 times smaller than any host detected in the near-infrared (NIR). In all cases, the five SMGs are comparable in sub-mm size to the two known quasars and four z approximate to 6 quasars, also observed with ALMA. We detect no evidence of diffuse spiral arms in this complete sample. We then convert the far-infrared (FIR) luminosities to star formation rate (SFR) surface densities and find that the SMGs occupy the same range as the known quasars in our sample. We conclude that in terms of sub-mm size, extent relative to host and SFR density as well as luminosity and mid-IR (MIR) colour, there is little distinction between the SMGs and sub-mm bright quasars. Finally, we present preliminary evidence that SMGs with higher MIR luminosities and sub-mm loud quasars tend to have dust components that range to hotter temperatures than their less luminous SMG counterparts. In light of these results, we continue to suggest that luminous SMGs may host dust-absorbed quasars that may simultaneously dominate the FIR and hard X-ray backgrounds.

The H alpha equivalent width (EW) is an observational proxy for specific star formation rate (sSFR) and a tracer of episodic, bursty star-formation activity. Previous assessments show that the H alpha EW strongly anticorrelates with stellar mass as M-0.25 similar to the sSFR - stellar mass relation. However, such a correlation could be driven or even formed by selection effects. In this study, we investigate how H alpha EW distributions correlate with physical properties of galaxies and how selection biases could alter such correlations using a z = 0.47 narrow-band-selected sample of 1572 H alpha emitters from the Ly alpha Galaxies in the Epoch of Reionization (LAGER) survey as our observational case study. The sample covers a 3 deg(2) area of COSMOS with a survey comoving volume of 1.1 x 10(5) Mpc(3). We assume an intrinsic EW distribution to form mock samples of H alpha emitters and propagate the selection criteria to match observations, giving us control on how selection biases can affect the underlying results. We find that H alpha EW intrinsically correlates with stellar mass as W-0 proportional to M-0.16 +/- 0.03 and decreases by a factor of similar to 3 from 10(7) M-circle dot to 10(10) M-circle dot, while not correcting for selection effects steepens the correlation as M-025 +/- 0.04, We find low-mass H alpha emitters to be similar to 320 times more likely to have rest-frame EW > 200 angstrom compared to high-mass H alpha emitters. Combining the intrinsic W-0-stellar mass correlation with an observed stellar mass function correctly reproduces the observed H alpha luminosity function, while not correcting for selection effects underestimates the number of bright emitters. This suggests that the W-0-stellar mass correlation when corrected for selection effects is physically significant and reproduces three statistical distributions of galaxy populations (line luminosity function, stellar mass function, EW distribution). At lower stellar masses, we find there are more high-EW outliers compared to high stellar masses, even after we take into account selection effects. Our results suggest that high sSFR outliers indicative of bursty star formation activity are intrinsically more prevalent in low-mass H alpha emitters and not a byproduct of selection effects.

Spatially extended halos of H i Ly alpha emission are now ubiquitously found around high-redshift star-forming galaxies. But our understanding of the nature and powering mechanisms of these halos is still hampered by the complex radiative transfer effects of the Ly alpha line and limited angular resolution. In this paper, we present resolved Multi Unit Spectroscopic Explorer (MUSE) observations of SGAS J122651.3+215220, a strongly lensed pair of L* galaxies at z = 2.92 embedded in a Ly alpha halo of L (Ly alpha ) = (6.2 +/- 1.3) x 10(42) erg s(-1). Globally, the system shows a line profile that is markedly asymmetric and redshifted, but its width and peak shift vary significantly across the halo. By fitting the spatially binned Ly alpha spectra with a collection of radiative transfer galactic wind models, we infer a mean outflow expansion velocity of approximate to 211 km s(-1), with higher values preferentially found on both sides of the system's major axis. The velocity of the outflow is validated with the blueshift of low-ionization metal absorption lines in the spectra of the central galaxies. We also identify a faint (M (1500) approximate to -16.7) companion detected in both Ly alpha and the continuum, whose properties are in agreement with a predicted population of satellite galaxies that contribute to the extended Ly alpha emission. Finally, we briefly discuss the impact of the interaction between the central galaxies on the properties of the halo and the possibility of in situ fluorescent Ly alpha production.

We report spectroscopic confirmations of 15 Ly alpha galaxies at z similar to 7, implying a spectroscopic confirmation rate of similar to 80% on candidates selected from the Ly alpha Galaxies in the Epoch of Reionization (LAGER), which is the largest (24 deg(2)) survey aimed at finding Ly alpha emitters (LAEs) at z similar to 7 and uses deep narrowband imaging from the Dark Energy Camera at CTIO. LAEs at high redshifts are sensitive probes of cosmic reionization, and narrowband imaging is a robust and effective method for selecting a large number of LAEs. In this work, we present results from the spectroscopic follow-up of LAE candidates in two LAGER fields, COSMOS and WIDE-12, using observations from Keck/LRIS. We report the successful detection of Ly alpha emission in 15 candidates. Three of these in COSMOS have matching confirmations from a previous spectroscopic follow-up and are part of the overdense region, LAGER-z7OD1. Two other candidates that were not detected with LRIS have prior spectroscopic confirmations from Magellan. Including these, we obtain a spectroscopic confirmation success rate of similar to 80% for LAGER LAE candidates. Thorough checks were performed to reject the possibility of these detections being foreground emission resulting with a probability of, at most, one contaminant. We do not detect any other UV nebular lines in our LRIS spectra, apart from Ly alpha. We estimate a 2 sigma upper limit for the ratio of N v/Ly alpha, f (NV)/f (Ly alpha ) less than or similar to 0.27. Including confirmations from this work, a total of 33 LAE sources from LAGER are now spectroscopically confirmed. LAGER has more than doubled the sample of spectroscopically confirmed LAE sources at z similar to 7.

We present a new measurement of the Ly alpha luminosity function (LF) at redshift z = 6.9, finding moderate evolution from z = 5.7 that is consistent with a fully or largely ionized z similar to 7 intergalactic medium. Our result is based on four fields of the LAGER (Lyman Alpha Galaxies in the Epoch of Reionization) project. Our survey volume of 6.1 x 10(6) Mpc(3) is double that of the next largest z similar to 7 survey. We combine two new LAGER fields (WIDE12 and GAMA15A) with two previously reported LAGER fields (COSMOS and CDFS). In the new fields, we identify N = 95 new z = 6.9 Ly alpha emitter (LAEs) candidates, characterize our survey's completeness and reliability, and compute Ly alpha LFs. The best-fit Schechter LF parameters for all four LAGER fields are in good general agreement. Two fields (COSMOS and WIDE12) show evidence for a bright-end excess above the Schechter function fit. We find that the Ly alpha luminosity density declines at the same rate as the UV continuum LF from z = 5.7 to 6.9. This is consistent with an intergalactic medium that was fully ionized as early as redshift z similar to 7 or with a volume-averaged neutral hydrogen fraction of x (H I) < 0.33 at 1 sigma.

We introduce a new color selection technique to identify high-redshift, massive galaxies that are systematically missed by Lyman-break selection. The new selection is based on the H-160 (H) and Infrared Array Camera (IRAC) 4.5 mu m bands, specifically H - [4.5] > 2.25 mag. These galaxies, called "HIEROs," include two major populations that can be separated with an additional J - H color. The populations are massive and dusty starforming galaxies at z > 3 (JH - blue) and extremely dusty galaxies at z less than or similar to 3 (JH - red). The 350 arcmin(2) of the GOODS-North and GOODS-South fields with the deepest Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) near-infrared and IRAC data contain as many as 285 HIEROs down to [4.5] < 24 mag. Inclusion of the most extreme HIEROs, not even detected in the H band, makes this selection particularly complete for the identification of massive high-redshift galaxies. We focus here primarily on JH - blue (z > 3) HIEROs, which have a median photometric redshift < z > similar to 4.4 and stellar mass M-* 10(10.6) M-circle dot and are much fainter in the rest-frame UV than similarly massive Lyman-break galaxies (LBGs). Their star formation rates (SFRs), derived from their stacked infrared spectral energy distributions (SEDs), reach similar to 240 M-circle dot yr(-1), leading to a specific SFR, sSFR equivalent to SFR/M-* similar to 4.2 Gyr(-1), suggesting that the sSFRs for massive galaxies continue to grow at z > 2 but at a lower growth rate than from z = 0 to z = 2. With a median half-light radius of 2 kpc, including similar to 20% as compact as quiescent (QS) galaxies at similar redshifts, JH - blue HIEROs represent perfect star-forming progenitors of the most massive (M-* greater than or similar to 10(11.2) M-circle dot) compact QS galaxies at z similar to 3 and have the right number density. HIEROs make up similar to 60% of all galaxies with M-* > 10(10.5) M-circle dot identified at z > 3 from their photometric redshifts. This is five times more than LBGs with nearly no overlap between the two populations. While HIEROs make up 15%-25% of the total SFR density at z similar to 4-5, they completely dominate the SFR density taking place in M-* 10(10.5) M-circle dot galaxies, and HIEROs are therefore crucial to understanding the very early phase of massive galaxy formation.

This work presents the first search for RR Lyrae stars (RRLs) in four he ultrafaint systems imaged by the Dark Energy Survey using SOAR/Goodman and Blanco/DECam imagers, We have detected two RRLs in the field of Grus I, none in Kim 2, one in Phoenix II, and four in Grus II. With the detection of these stars, we accurately determine the distance moduli for these ultrafaint dwarf satellite galaxies; mu(0) = 20.51 +/- 0.10 mag (D-circle dot = 127 +/- 6 kpc) for Grus I and mu(0) = 20.01 +/- 0.10 mag (D-circle dot = 100 +/- 5 kpc) for Phoenix IL These measurements are larger than previous estimations by Koposov et al. and Bechtol et al., implying larger physical sizes; S per cent for Grus I and 33 per cent for Phoenix II. For Grus II, of the four RRLs detected, one is consistent with being a member of the galactic halo (D-circle dot = 24 +/- 1 kpc, mu(0) = 16.86 +/- 0.10 mag), another is at D-circle dot = 55 +/- 2 kpc (mu(0) = 18.71 +/- 0.10 mag), which we associate with Grus II, and the two remaining at D-circle dot = 43 +/- 2 kpc (mu(0) = 18.17 +/- 0.10 mag). Moreover, the appearance of a subtle red horizontal branch in the colour magnitude diagram of Grus II at the same brightness level of the latter two RRLs, which are at the same distance and in the same region, suggests that a more metal-rich system may be located in front of Grus II. The most plausible scenario is the association of these stars with the Chenab/Orphan Stream. Finally, we performed a comprehensive and updated analysis of the number of RRLs in dwarf galaxies. This allows us to predict that the method of finding new ultrafaint dwarf galaxies using two or more clumped RRLs will work only for systems brighter than M-V similar to 6 mag.