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Supernova (SN) H0pe is a gravitationally lensed, triply-imaged, Type Ia SN (SN Ia) discovered in James Webb Space Telescope imaging of the PLCK G165.7+67.0 cluster of galaxies. Well-observed multiply-imaged SNe provide a rare opportunity to constrain the Hubble constant (\\(H_0\\)), by measuring the relative time delay between the images and modeling the foreground mass distribution. SN H0pe is located at \\(z=1.783\\), and is the first SN Ia with sufficient light curve sampling and long enough time delays for an \\(H_0\\) inference. Here we present photometric time-delay measurements and SN properties of SN H0pe. Using JWST/NIRCam photometry we measure time delays of \\(\\Delta t_{ab}=-116.6^{+10.8}_{-9.3}\\) and \\(\\Delta t_{cb}=-48.6^{+3.6}_{-4.0}\\) observer-frame days relative to the last image to arrive (image 2b; all uncertainties are \\(1\\sigma\\)), which corresponds to a \\(\\sim5.6\\%\\) uncertainty contribution for \\(H_0\\) assuming \\(70 \\rm{km s^{-1} Mpc^{-1}}\\). We also constrain the absolute magnification of each image to \\(\\mu_{a}=4.3^{+1.6}_{-1.8}\\), \\(\\mu_{b}=7.6^{+3.6}_{-2.6}\\), \\(\\mu_{c}=6.4^{+1.6}_{-1.5}\\) by comparing the observed peak near-IR magnitude of SN H0pe to the non-lensed population of SNe Ia.

Supernova (SN) H0pe was discovered as a new transient in James Webb Space Telescope (JWST) NIRCam images of the galaxy cluster PLCK G165.7+67.0 taken as part of the \"Prime Extragalactic Areas for Reionization and Lensing Science\" (PEARLS) JWST GTO program (# 1176) on 2023 March 30 (AstroNote 2023-96; Frye et al. 2023). The transient is a compact source associated with a background galaxy that is stretched and triply-imaged by the cluster's strong gravitational lensing. This paper reports spectra in the 950-1370 nm observer frame of two of the galaxy's images obtained with Large Binocular Telescope (LBT) Utility Camera in the Infrared (LUCI) in longslit mode two weeks after the \\JWST\\ observations. The individual average spectra show the [OII] doublet and the Balmer and 4000 Angstrom breaks at redshift z=1.783+/-0.002. The CIGALE best-fit model of the spectral energy distribution indicates that SN H0pe's host galaxy is massive (Mstar~6x10^10 Msun after correcting for a magnification factor ~7) with a predominant intermediate age (~2 Gyr) stellar population, moderate extinction, and a magnification-corrected star formation rate ~13 Msun/yr, consistent with being below the main sequence of star formation. These properties suggest that H0pe might be a type Ia SN. Additional observations of SN H0pe and its host recently carried out with JWST (JWST-DD-4446; PI: B. Frye) will be able to both determine the SN classification and confirm its association with the galaxy analyzed in this work.

The case is outlined for a new galaxy survey, including spectroscopy with AAOmega and sub-arcsecond multi-band imaging, that bridges a crucial gap between the SDSS and VVDS surveys. The science focus is to study structure and the relationship between matter and light on kpc-to-Mpc scales. The range of scales probed will enable direct constraints on the Cold Dark Matter model by: (1) measuring the halo mass function down to $10^{12}{\\cal M}_{\\odot}$ and its evolution to z ~ 0.4; (2) measuring the galaxy stellar mass function to very low mass limits of $10^{7}{\\cal M}_{\\odot}$ constraining baryonic feedback processes; and (3) quantifying the environment-dependent merger rate since z ~ 0.4. Here, we highlight the fact that the high-resolution imaging will enable the bulge-disk decomposition of ~200000 galaxies in u–K, providing a valuable resource for statistical studies of bulge properties.

The identification of AGN in large surveys has been hampered by seemingly discordant classifications arising from differing diagnostic methods, usually tracing distinct processes specific to a particular wavelength regime. However, as shown in Yao et al. (2020), the combination of optical emission line measurements and mid-infrared photometry can be used to optimise the discrimination capability between AGN and star formation activity. In this paper we test our new classification scheme by combining the existing GAMA-WISE data with high-quality MeerKAT radio continuum data covering 8 deg\\(^2\\) of the GAMA G23 region. Using this sample of 1 841 galaxies (z < 0.25), we investigate the total infrared (derived from 12\\(\\mu\\)m) to radio luminosity ratio, q(TIR), and its relationship to optical-infrared AGN and star-forming (SF) classifications. We find that while q(TIR) is efficient at detecting AGN activity in massive galaxies generally appearing quiescent in the infrared, it becomes less reliable for cases where the emission from star formation in the host galaxy is dominant. However, we find that the q(TIR) can identify up to 70 % more AGNs not discernible at optical and/or infrared wavelengths. The median q(TIR) of our SF sample is 2.57 \\(\\pm\\) 0.23 consistent with previous local universe estimates.

We introduce ProSpect, a generative galaxy spectral energy distribution (SED) package that encapsulates the best practices for SED methodologies in a number of astrophysical domains. ProSpect comes with two popular families of stellar population libraries (BC03 and EMILES), and a large variety of methods to construct star formation and metallicity histories. It models dust through the use of a Charlot & Fall attenuation model, with re-emission using Dale far-infrared templates. It also has the ability to model AGN through the inclusion of a simple AGN and hot torus model. Finally, it makes use of MAPPINGS-III photoionisation tables to produce line emission features. We test the generative and inversion utility of ProSpect through application to the Shark galaxy formation semi-analytic code, and informed by these results produce fits to the final ultraviolet to far-infrared photometric catalogues produces by the Galaxy and Mass Assembly Survey (GAMA). As part of the testing of ProSpect, we also produce a range of simple photometric stellar mass approximations covering a range of filters for both observed frame and rest frame photometry.

We investigate the properties of 232 optical spectroscopically selected groups from the Galaxy And Mass Assembly (GAMA) survey that overlap the XXL X-ray cluster survey. X-ray aperture flux measurements combined with GAMA group data provides the largest available sample of optical groups with detailed galaxy membership information and consistently measured X-ray fluxes and upper limits. 142 of these groups are divided into three subsets based on the relative strength of X-ray and optical emission, and we see a trend in galaxy properties between these subsets: X-ray overluminous groups contain a lower fraction of both blue and star forming galaxies compared with X-ray underluminous systems. X-ray overluminous groups also have a more dominant central galaxy, with a magnitude gap between first and second ranked galaxies on average 0.22 mag larger than in underluminous groups. The central galaxy in overluminous groups also lies closer to the centre of the group. We examine a number of other structural properties of our groups, such as axis ratio, velocity dispersion, and group crossing time and find trends with X-ray emission in some of these properties despite the high stochastic noise from the limited number of group galaxies. We attribute the trends we see to the evolutionary state of groups, with X-ray overluminous systems being more dynamically evolved than underluminous groups. The X-ray overluminous groups have had more time to develop a luminous intragroup medium, quench member galaxies, and build the mass of the central galaxy through mergers compared to underluminous groups. However, a minority of X-ray underluminous groups have properties that suggest them to be dynamically mature. The lack of hot gas in these systems cannot be accounted for by high star formation efficiency, suggesting that high gas entropy resulting from feedback is the likely cause of their weak X-ray emission.