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We study the projected spatial offset between the ultraviolet continuum and Ly α emission for 65 lensed and unlensed galaxies in the Epoch of Reionization (5 ≤ z ≤ 7), the first such study at these redshifts, in order to understand the potential for these offsets to confuse estimates of the Ly α properties of galaxies observed in slit spectroscopy. While we find that ∼40 per cent of galaxies in our sample show significant projected spatial offsets ($|\Delta {\rm {Ly}\alpha -\rm {UV}}|$), we find a relatively modest average projected offset of $|\widetilde{\Delta }{\rm {Ly}\alpha -\rm {UV}}|$ = 0.61 ± 0.08 proper kpc for the entire sample. A small fraction of our sample, ∼10 per cent, exhibit offsets in excess of 2 proper kpc, with offsets seen up to ∼4 proper kpc, sizes that are considerably larger than the effective radii of typical galaxies at these redshifts. An internal comparison and a comparison to studies at lower redshift yielded no significant evidence of evolution of $|\Delta {\rm {Ly}\alpha -\rm {UV}}|$ with redshift. In our sample, ultraviolet (UV)-bright galaxies ($\widetilde{L{\mathrm{ UV}}}/L{\ast }{\mathrm{ UV}}=0.67$) showed offsets a factor of three greater than their fainter counterparts ($\widetilde{L{\mathrm{ UV}}}/L{\ast }{\mathrm{ UV}}=0.10$), 0.89 ± 0.18 versus 0.27 ± 0.05 proper kpc, respectively. The presence of companion galaxies and early stage merging activity appeared to be unlikely causes of these offsets. Rather, these offsets appear consistent with a scenario in which internal anisotropic processes resulting from stellar feedback, which is stronger in UV-brighter galaxies, facilitate Ly α fluorescence and/or backscattering from nearby or outflowing gas. The reduction in the Ly α flux due to offsets was quantified. It was found that the differential loss of Ly α photons for galaxies with average offsets is not, if corrected for, a limiting factor for all but the narrowest slit widths (

We present deep spectroscopic observations of a Lyman break galaxy (LBG) candidate (hereafter MACS1149-JD) at z ∼ 9.5 with the Hubble Space Telescope (HST) WFC3/IR grisms. The grism observations were taken at four distinct position angles, totaling 34 orbits with the G141 grism, although only 19 of the orbits are relatively uncontaminated along the trace of MACS1149-JD. We fit a three-parameter (z, F160W mag, and Lyα equivalent width [EW]) LBG template to the three least contaminated grism position angles using a Markov chain Monte Carlo approach. The grism data alone are best fit with a redshift of (68% confidence), in good agreement with our photometric estimate of (68% confidence). Our analysis rules out Lyα emission from MACS1149-JD above a 3σ EW of 21 Å, consistent with a highly neutral IGM. We explore a scenario where the red Spitzer/IRAC [3.6]-[4.5] color of the galaxy previously pointed out in the literature is due to strong rest-frame optical emission lines from a very young stellar population rather than a 4000 Å break. We find that while this can provide an explanation for the observed IRAC color, it requires a lower redshift (z ≲ 9.1), which is less preferred by the HST imaging data. The grism data are consistent with both scenarios, indicating that the red IRAC color can still be explained by a 4000 Å break, characteristic of a relatively evolved stellar population. In this interpretation, the photometry indicates that a Myr stellar population is already present in this galaxy only ∼500 Myr after the big bang.

The C iii] and C iv rest-frame UV emission lines are powerful probes of the ionization states of galaxies. They have furthermore been suggested as alternatives for spectroscopic redshift confirmation of objects at the epoch of reionization (), where the most frequently used redshift indicator, Lyα, is attenuated by the high fraction of neutral hydrogen in the intergalactic medium. However, currently only very few confirmations of carbon UV lines at these high redshifts exist, making it challenging to quantify these claims. Here, we present the detection of C iv λλ1548, 1551 Å in Hubble Space Telescope slitless grism spectroscopy obtained by GLASS of a Lyα emitter at z = 6.11 multiply imaged by the massive foreground galaxy cluster RXC J2248.7-4431. The C iv emission is detected at the 3σ-5σ level in two images of the source, with marginal detection in two other images. We do not detect significant C iii]λλ1907, 1909 Å emission implying an equivalent width Å (1σ) and (2σ). Combined with limits on the rest-frame UV flux from the He ii λ1640 Å emission line and the O iii]λλ1661, 1666 Å doublet, we put constraints on the metallicity and the ionization state of the galaxy. The estimated line ratios and equivalent widths do not support a scenario where an AGN is responsible for ionizing the carbon atoms. SED fits, including nebular emission lines, imply a source with a mass of log(M/M o) ∼ 9, SFR of around 10 M o yr-1, and a young stellar population old. The source shows a stronger ionizing radiation field than objects with detected C iv emission at and adds to the growing sample of low-mass (log(M/M o) ≲ 9) galaxies at the epoch of reionization with strong radiation fields from star formation.

Context: Canola meal is a protein-rich feedstuff with an amino acid profile that is reasonably well balanced and has the potential to replace soybean meal in poultry diets. Aim: The objective of the present study was to investigate the relationship between the crude protein content and apparent ileal digestible amino acid contents of Australian canola meals. Methods: Thirteen canola meal samples, processed by expeller or solvent extractions, were collected. The digestibility assay diets were based on dextrose and contained canola meal as the sole source of protein. The proportions of dextrose and canola meal were varied in each diet to obtain ~200 g/kg crude protein. Each diet was fed to three cages of six 35-day-old broilers for 7 days. At the end of the assay, digesta from the terminal ileum was collected for digestibility determination. Key results: Crude protein contents were positively correlated with amino acid contents (P < 0.05 to 0.001), except that of serine (r = 0.43; P = 0.11). Significant correlations between the crude protein content and ileal digestible contents were observed for most of amino acids, with coefficients of >0.80 (P < 0.05 to 0.001). Low correlation coefficients were observed for lysine (r = 0.48; P = 0.11) and serine (r = 0.55; P = 0.06). The poor correlation for lysine may be reflective of reduced lysine availability during processing. Conclusions: The results showed that the crude protein content of canola meal could serve as a predictor of apparent ileal digestible content of most amino acids for broiler chickens. Implications: Regression equations developed in the present study could be used to predict the content of ileal digestible amino acids in canola meal by using analysed crude protein contents. Canola meal (CM) is a potentially important protein source for poultry. The amino acid profile of CM is reasonably well balanced, but digestibility of amino acids is key to the nutritional value of CM. Amino acid analysis and in vivo digestibility assays are costly and time consuming. The aim of this study was to determine whether the digestible amino acid content of CM could be deduced from its crude protein content, which is routinely determined. This article belongs to the Collection Sustainable Animal Agriculture for Developing Countries 2023. [ABSTRACT FROM AUTHOR]

We present a census of Lyα emission at z ≳ 7, utilizing deep near-infrared Hubble Space Telescope grism spectroscopy from the first six completed clusters of the Grism Lens-Amplified Survey from Space (GLASS). In 24/159 photometrically selected galaxies we detect emission lines consistent with Lyα in the GLASS spectra. Based on the distribution of signal-to-noise ratios and on simulations, we expect the completeness and the purity of the sample to be 40%-100% and 60%-90%, respectively. For the objects without detected emission lines we show that the observed (not corrected for lensing magnification) 1σ flux limits reach 5 × 10-18 erg s-1 cm-2 per position angle over the full wavelength range of GLASS (0.8-1.7 μm). Based on the conditional probability of Lyα emission measured from the ground at z ∼ 7, we would have expected 12-18 Lyα emitters. This is consistent with the number of detections, within the uncertainties, confirming the drop in Lyα emission with respect to z ∼ 6. Deeper follow-up spectroscopy, here exemplified by Keck spectroscopy, is necessary to improve our estimates of completeness and purity and to confirm individual candidates as true Lyα emitters. These candidates include a promising source at z = 8.1. The spatial extent of Lyα in a deep stack of the most convincing Lyα emitters with 'z' = 7.2 is consistent with that of the rest-frame UV continuum. Extended Lyα emission, if present, has a surface brightness below our detection limit, consistent with the properties of lower-redshift comparison samples. From the stack we estimate upper limits on rest-frame UV emission line ratios and find fC IV/fLyα ≳ 0.32 and fC III/fLyα ≳ 0.32, in good agreement with other values published in the literature.

We give an overview of the Grism Lens Amplified Survey from Space (GLASS), a large Hubble Space Telescope program aimed at obtaining grism spectroscopy of the fields of 10 massive clusters of galaxies at redshift z = 0.308-0.686, including the Hubble Frontier Fields (HFF). The Wide Field Camera 3 (WFC3) yields near-infrared spectra of the cluster cores covering the wavelength range 0.81-1.69 μm through grisms G102 and G141, while the Advanced Camera for Surveys in parallel mode provides G800L spectra of the infall regions of the clusters. The WFC3 spectra are taken at two almost orthogonal position angles in order to minimize the effects of confusion. After summarizing the scientific drivers of GLASS, we describe the sample selection as well as the observing strategy and data processing pipeline. We then utilize MACS J0717.5+3745, a HFF cluster and the first one observed by GLASS, to illustrate the data quality and the high-level data products. Each spectrum brighter than is visually inspected by at least two co-authors and a redshift is measured when sufficient information is present in the spectra. Furthermore, we conducted a thorough search for emission lines through all of the GLASS WFC3 spectra with the aim of measuring redshifts for sources with continuum fainter than We provide a catalog of 139 emission-line-based spectroscopic redshifts for extragalactic sources, including three new redshifts of multiple image systems (one probable, two tentative). In addition to the data itself, we also release software tools that are helpful to navigate the data.

We present a strong and weak lensing reconstruction of the massive cluster Abell 2744, the first cluster for which deep Hubble Frontier Fields (HFF) images and spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) are available. By performing a targeted search for emission lines in multiply imaged sources using the GLASS spectra, we obtain five high-confidence spectroscopic redshifts and two tentative ones. We confirm one strongly lensed system by detecting the same emission lines in all three multiple images. We also search for additional line emitters blindly and use the full GLASS spectroscopic catalog to test reliability of photometric redshifts for faint line emitters. We see a reasonable agreement between our photometric and spectroscopic redshift measurements, when including nebular emission in photometric redshift estimations. We introduce a stringent procedure to identify only secure multiple image sets based on colors, morphology, and spectroscopy. By combining 7 multiple image systems with secure spectroscopic redshifts (at 5 distinct redshift planes) with 18 multiple image systems with secure photometric redshifts, we reconstruct the gravitational potential of the cluster pixellated on an adaptive grid, using a total of 72 images. The resulting mass map is compared with a stellar mass map obtained from the deep Spitzer Frontier Fields data to study the relative distribution of stars and dark matter in the cluster. We find that the stellar to total mass ratio varies substantially across the cluster field, suggesting that stars do not trace exactly the total mass in this interacting system. The maps of convergence, shear, and magnification are made available in the standard HFF format.

Unmanned aerial vehicle (UAV) swarm coverage is one of the key technologies for multi-UAV cooperation, which plays an important role in collaborative investigation, detection, rescue and other applications. Aiming at the coverage optimisation problem of UAV in the target area, a collaborative visual coverage control method under positioning uncertainty is presented. First, the visual perception area with imprecise localisation, UAV model and sensor model are created based on the given task environment. Second, a regional division algorithm for the target task area is designed based on the principle of Guaranteed Voronoi (GV) diagram. Then a visual area coverage planning algorithm is designed, in which the task area is allocated to the UAV according to the corresponding weight coefficient of each area, and the input control law is adjusted by the expected state information of the UAV, so that the optimal coverage quality target value and the maximum coverage of the target area can be achieved. Finally, three task scenarios for regional division and coverage planning are simulated respectively, the results show that the proposed area coverage planning algorithm can realise the optimal regional distribution and can obtain more than 90% coverage in different scenarios. [ABSTRACT FROM AUTHOR]