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Panning for gold, but finding helium: Discovery of the ultra-stripped supernova SN 2019wxt from gravitational-wave follow-up observations
(EDP Sciences, 2023-07) Agudo I.; Amati L.; An T.; Bauer F.E.; Benetti S.; Bernardini M.G.; Beswick R.; Bhirombhakdi K.; De Boer T.; Branchesi M.; Brennan S.J.; Brocato E.; Caballero-García M.D.; Cappellaro E.; Castro Rodríguez N.; Castro-Tirado A.J.; Chambers K.C.; Chassande-Mottin E.; Chaty S.; Chen T.-W.; Coleiro A.; Covino S.; Da'ammando F.; Da'avanzo P.; Da'elia V.; Fiore A.; Flörs A.; Fraser M.; Frey S.; Frohmaier C.; Fulton M.; Galbany L.; Gall C.; Gao H.; García-Rojas J.; Ghirlanda G.; Giarratana S.; Gillanders J.H.; Giroletti M.; Gompertz B.P.; Gromadzki M.; Heintz K.E.; Hjorth J.; Hu Y.-D.; Huber M.E.; Inkenhaag A.; Izzo L.; Jin Z.P.; Jonker P.G.; Kann D.A.; Kool E.C.; Kotak R.; Leloudas G.; Levan A.J.; Lin C.-C.; Lyman J.D.; Magnier E.A.; Maguire K.; Mandel I.; Marcote B.; Mata Sánchez D.; Mattila S.; Mattila S.; Michaåà  Owski M.J.; Moldon J.; Nicholl M.; Nicuesa Guelbenzu A.; Oates S.R.; Onori F.; Orienti M.; Paladino R.; Paragi Z.; Perez-Torres M.; Pian E.; Pignata G.; Piranomonte S.; Quirola-Vásquez J.; Ragosta F.; Rau A.; Ronchini S.; Rossi A.; Sánchez-Ramírez R.; Salafia O.S.; Schulze S.; Smartt S.J.; Smith K.W.; Sollerman J.; Srivastav S.; Starling R.L.C.; Steeghs D.; Stevance H.F.; Tanvir N.R.; Testa V.; Torres M.A.P.; Valeev A.; Vergani S.D.; Vescovi D.; Wainscost R.; Watson D.; Wiersema K.; Wyrzykowski L.; Yang J.; Yang S.; Young D.R.
We present the results from multi-wavelength observations of a transient discovered during an intensive follow-up campaign of S191213g, a gravitational wave (GW) event reported by the LIGO-Virgo Collaboration as a possible binary neutron star merger in a low latency search. This search yielded SN 2019wxt, a young transient in a galaxy whose sky position (in the 80% GW contour) and distance (∼150 Mpc) were plausibly compatible with the localisation uncertainty of the GW event. Initially, the transienta's tightly constrained age, its relatively faint peak magnitude (Mi ∼ -16.7 mag), and the r-band decline rate of ∼1 mag per 5 days appeared suggestive of a compact binary merger. However, SN 2019wxt spectroscopically resembled a type Ib supernova, and analysis of the optical-near-infrared evolution rapidly led to the conclusion that while it could not be associated with S191213g, it nevertheless represented an extreme outcome of stellar evolution. By modelling the light curve, we estimated an ejecta mass of only ∼0.1 M·, with 56Ni comprising ∼20% of this. We were broadly able to reproduce its spectral evolution with a composition dominated by helium and oxygen, with trace amounts of calcium. We considered various progenitor channels that could give rise to the observed properties of SN 2019wxt and concluded that an ultra-stripped origin in a binary system is the most likely explanation. Disentangling genuine electromagnetic counterparts to GW events from transients such as SN 2019wxt soon after discovery is challenging: in a bid to characterise this level of contamination, we estimated the rate of events with a volumetric rate density comparable to that of SN 2019wxt and found that around one such event per week can occur within the typical GW localisation area of O4 alerts out to a luminosity distance of 500 Mpc, beyond which it would become fainter than the typical depth of current electromagnetic follow-up campaigns. © 2023 Authors
Neuro-Vulnerability in Energy Metabolism Regulation: A Comprehensive Narrative Review
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-07) Clemente-Suárez, Vicente Javier; Beltrán-Velasco, Ana Isabel; Redondo-Flórez, Laura; Martín-Rodríguez, Alexandra; Yáñez-Sepúlveda, Rodrigo; Tornero-Aguilera, José Francisco
This comprehensive narrative review explores the concept of neuro-vulnerability in energy metabolism regulation and its implications for metabolic disorders. The review highlights the complex interactions among the neural, hormonal, and metabolic pathways involved in the regulation of energy metabolism. The key topics discussed include the role of organs, hormones, and neural circuits in maintaining metabolic balance. The review investigates the association between neuro-vulnerability and metabolic disorders, such as obesity, insulin resistance, and eating disorders, considering genetic, epigenetic, and environmental factors that influence neuro-vulnerability and subsequent metabolic dysregulation. Neuroendocrine interactions and the neural regulation of food intake and energy expenditure are examined, with a focus on the impact of neuro-vulnerability on appetite dysregulation and altered energy expenditure. The role of neuroinflammation in metabolic health and neuro-vulnerability is discussed, emphasizing the bidirectional relationship between metabolic dysregulation and neuroinflammatory processes. This review also evaluates the use of neuroimaging techniques in studying neuro-vulnerability and their potential applications in clinical settings. Furthermore, the association between neuro-vulnerability and eating disorders, as well as its contribution to obesity, is examined. Potential therapeutic interventions targeting neuro-vulnerability, including pharmacological treatments and lifestyle modifications, are reviewed. In conclusion, understanding the concept of neuro-vulnerability in energy metabolism regulation is crucial for addressing metabolic disorders. This review provides valuable insights into the underlying neurobiological mechanisms and their implications for metabolic health. Targeting neuro-vulnerability holds promise for developing innovative strategies in the prevention and treatment of metabolic disorders, ultimately improving metabolic health outcomes. © 2023 by the authors.
Rubin Observatory LSST Stars Milky Way and Local Volume Star Clusters Roadmap
(Institute of Physics, 2023-07) Usher, Christopher; Dage, Kristen C.; Girardi, Léo; Barmby, Pauline; Bonatto, Charles J.; Chies-Santos, Ana L.; Clarkson, William I.; Camus, Matias Gómez; Hartmann, Eduardo A.; Ferguson, Annette M. N.; Pieres, Adriano; Prisinzano, Loredana; Rhode, Katherine L.; Rich, R. Michael; Ripepi, Vincenzo; Santiago, Basilio; Stassun, Keivan G.; Street R.A.; Szabó, Róbert; Venuti, Laura; Zaggia, Simone; Canossa, Marco; Floriano, Pedro; Lopes, Pedro; Miranda, Nicole L.; Oliveira, Raphael A. P.; Reina-Campos, Marta; Roman-Lopes A.; Sobeck, Jennifer
The Vera C. Rubin Observatory will undertake the Legacy Survey of Space and Time, providing an unprecedented, volume-limited catalog of star clusters in the Southern Sky, including Galactic and extragalactic star clusters. The Star Clusters subgroup of the Stars, Milky Way and Local Volume Working Group has identified key areas where Rubin Observatory will enable significant progress in star cluster research. This roadmap represents our science cases and preparation for studies of all kinds of star clusters from the Milky Way out to distances of tens of megaparsecs. © 2023. The Author(s). Published by IOP Publishing Ltd on behalf of the Astronomical Society of the Pacific (ASP). All rights reserved.
The ionizing photon production efficiency of bright z ~ 2-5 galaxies
(EDP Sciences, 2023-07) Castellano M.; Belfiori D.; Pentericci L.; Calabrò A.; Mascia S.; Napolitano L.; Caro F.; Charlot S.; Chevallard J.; Curtis Lake E.; Talia M.; Bongiorno A.; Fontana A.; Fynbo J.P.U.; Garilli B.; Guaita L.; McLure R.J.; Merlin E.; Mignoli M.; Moresco M.; Pompei E.; Pozzetti L.; Saldana Lopez A.; Saxena A.; Santini P.; Schaerer D.; Schreiber C.; Shapley A.E.; Vanzella E.; Zamorani G.
Aims. We investigate the production efficiency of ionizing photons (ξion∗) of 1174 galaxies with secure redshift at z=2 - 5 from the VANDELS survey to determine the relation between ionizing emission and physical properties of bright and massive sources. Methods. We constrained ξion∗ and galaxy physical parameters by means of spectrophotometric fits performed with the BEAGLE code. The analysis exploits the multi-band photometry in the VANDELS fields and the measurement of UV rest-frame emission lines (CIII]λ1909, HeIIλ1640, and OIII]λ1666) from deep VIMOS spectra. Results. We find no clear evolution of ξion∗ with redshift within the probed range. The ionizing efficiency slightly increases at fainter MUV and bluer UV slopes, but these trends are less evident when the analysis is restricted to a complete subsample at log(Mstar/M⊙) > 9.5. We find a significant trend of increasing ξion∗ with increasing EW(Lyα), with an average log(ξion∗/Hz erg-1) > 25 at EW > 50 Åand a higher ionizing efficiency for high-EW CIII]λ1909 and OIII]λ1666 emitters. The most significant correlations are found with respect to stellar mass, specific star formation rate (sSFR), and SFR surface density (ΣSFR). The relation between ξion∗ and sSFR increases monotonically from log(ξion∗/Hz erg-1)~24.5 at log(sSFR)~-9.5yr-1 to ~25.5 at log(sSFR)~-7.5yr-1. This relation has a low scatter and only a weak dependence on mass. The objects above the main sequence of star formation consistently have higher than average ξion∗. A clear increase in ξion∗ with ΣSFR is also found, with log(ξion∗/Hz erg-1) > 25 for objects at ΣSFR>10M⊙ yr-1 kpc-2. Conclusions. Bright (MUV≲20) and massive (log(Mstar/M⊙)≳9.5) galaxies at z=2 - 5 have a moderate ionizing efficiency. However, the correlation between ξion∗ and sSFR, together with the known increase in the average sSFR with redshift at fixed stellar mass, suggests that similar galaxies in the epoch of reionization can be efficient sources of ionizing photons. The availability of sSFR and ΣSFR as proxies for ξion∗ can be fundamentally important in determining the role of galaxy populations at z≳10 that were recently discovered by the James Webb Space Telescope in the onset of reionization. © 2023 EDP Sciences. All rights reserved.
The ALMA Frontier Fields Survey: VI. Lensing-corrected 1.1 mm number counts in Abell 2744, MACSJ0416.1-2403, MACSJ1149.5+2223, Abell 370, and Abell S1063
(EDP Sciences, 2023) Muñoz Arancibia A.M.; González-López J.; Ibar E.; Bauer F.E; Anguita T.; Aravena M.; Demarco R.; Kneissl R.; Koekemoer A.M.; Troncoso-Iribarren P.; Zitrin A.
Context. Probing the faint end of the number counts at millimeter wavelengths is important in order to identify the origin of the extragalactic background light in this regime. Aided by strong gravitational lensing, ALMA observations toward massive galaxy clusters have opened a window to probe this origin, allowing us to resolve sub-milliJansky dusty star-forming galaxies. Aims. We aim to derive number counts at 1.1 mm down to flux densities fainter than 0.1 mJy based on ALMA observations toward five Hubble Frontier Fields (FF) galaxy clusters, following a statistical approach to correct for lensing effects. Methods. We created a source catalog that includes ALMA 1.1 mm continuum detections around two new FF galaxy clusters, together with the sources previously detected around three FF galaxy clusters, making a total of 29 detected sources down to a 4.5σ significance. ALMA 1.1 mm mosaics used for our source extraction covered the inner ≈2′ × 2′; FF regions, reached rms depths of ≈55 - 71μJy beam-1, and had synthesized beam sizes from ≈0″.5 - 1″.5 (natural weighting). We derived source intrinsic flux densities using public lensing models. We folded the uncertainties in both magnifications and source redshifts into the number counts through Monte Carlo simulations. Results. Using the combination of all cluster fields, we derive cumulative number counts over two orders of magnitude down to ≈0.01 mJy after correction for lensing effects. Cosmic variance estimates are all exceeded by uncertainties in our median combined cumulative counts that come from both our Monte Carlo simulations and Poisson statistics. Our number counts agree at a 1σ level with our previous estimates using ALMA observations of the first three FFs, exhibiting a similar flattening at faint flux densities. They are also consistent to 1σ with most recent ALMA estimates and galaxy evolution models. However, below ≈0.1 mJy, our cumulative number counts are lower by ≈0.4 dex compared to two deep ALMA studies (namely one that probes several blank fields plus one lensed galaxy cluster, and the initial ALMA Spectroscopic Survey in the Hubble Ultra Deep Field, ASPECS-Pilot), while remaining consistent with the ASPECS Large Program (ASPECS-LP) within 1σ. Importantly, the flattening found for our cumulative counts at ≲0.1 mJy also extends further to ≈0.01 mJy, that is, ≈0.4 dex fainter than ASPECS-LP, and remains in agreement with extrapolations of their number counts down to this flux limit. We find a median contribution to the extragalactic background light (EBL) of 14-8+12 Jy deg-2 resolved in our demagnified sources down to ≈0.01 mJy, representing 75 - 86% of Planck-derived extragalactic EBL estimates at 1.1 mm. Conclusions. We estimate cumulative 1.1 mm number counts down to ≈0.01 mJy along the line of sight of five galaxy clusters that benefit from having rich deep multiwavelength data. They bring further support to the flattening of the number counts reported previously by us and ASPECS-LP, which has been interpreted by a recent galaxy evolution model as a measurement of the "knee"of the infrared luminosity function at high redshift. Our estimates of the contribution to the EBL associated with 1.1 mm galaxies in the FFs suggest that we may be resolving most of the EBL at this wavelength down to ≈0.01 mJy. © M. Grandin et al., Published by EDP Sciences 2023M. Grandin et al., Published by EDP Sciences 2023