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THESEUS, one of the two space mission concepts being studied by ESA as candidates for next M5 mission within its Comsic Vision programme, aims at fully exploiting Gamma-Ray Bursts (GRB) to solve key questions about the early Universe, as well as becoming a cornerstone of multi-messenger and time-domain astrophysics. By investigating the first billion years of the Universe through high-redshift GRBs, THESEUS will shed light on the main open issues in modern cosmology, such as the population of primordial low mass and luminosity galaxies, sources and evolution of cosmic re-ionization, SFR and metallicity evolution up to the “cosmic dawn” and across Pop-III stars. At the same time, the mission will provide a substantial advancement of multi-messenger and time-domain astrophysics by enabling the identification, accurate localisation and study of electromagnetic counterparts to sources of gravitational waves and neutrinos, which will be routinely detected in the late ‘20s and early ‘30s by the second and third generation Gravitational Wave (GW) interferometers and future neutrino detectors, as well as of all kinds of GRBs and most classes of other X/gamma-ray transient sources. Under all these respects, THESEUS will provide great synergies with future large observing facilities in the multi-messenger domain. A Guest Observer programme, comprising Target of Opportunity (ToO) observations, will expand the science return of the mission, to include, e.g., solar system minor bodies, exoplanets, and AGN.

The early and complete temporal characterization of optical, fast, transient sources requires continuous and multiband observations over different timescales (hours to months). For time-domain astronomy, using several telescopes to analyze single objects is the usual method, allowing the acquisition of highly sampled light curves. Taking a series of images each night helps to construct an uninterrupted chain of observations with a high cadence and low duty cycle. Speed is paramount, especially at early times, in order to capture early features in the light curve that help determine the nature of the observed transients and assess their astrophysical properties. However, the problem of rapidly extracting source properties (temporal and color evolution) with a heterogeneous data set remains. Consequently, we present Muphoten , a general and fast-computation photometric pipeline able to address these constraints. It is suitable for extracting transient brightness over multitelescope and multiband networks to create a single homogeneous photometric time series. We show the performance of Muphoten with observations of the optical transient SN 2018cow (from 2018 June to 2018 July), monitored by the GRANDMA network and with the publicly available data of the Liverpool Telescope.

A galaxy at redshift z ≈ 8.6 Until now, the most distant spectroscopically confirmed galaxies known in the Universe were at redshifts z ≈ 8.2 and z ≈ 6.96. Lehnert et al . now report that UDFy-38135539 is at a redshift of z = 8.6. The galaxy was first identified as a candidate z ≈ 8.6 object in deep Wide Field Camera 3 observations of the Hubble Ultra Deep Field, and the discovery in ground-based observations that it is emitting Lyman-α photons provides confirmation. This single source is unlikely to provide enough photons to ionize the volume necessary for the emission line to escape, requiring a significant contribution from other, probably fainter galaxies nearby. Until now, the most distant spectroscopically confirmed galaxies known in the Universe were at redshifts of z = 8.2 and z = 6.96. It is now reported that the galaxy UDFy-38135539 is at a redshift of z = 8.5549 ± 0.0002. The finding has implications for our understanding of the timing, location and nature of the sources responsible for reionization of the Universe after the Big Bang. Galaxies had their most significant impact on the Universe when they assembled their first generations of stars. Energetic photons emitted by young, massive stars in primeval galaxies ionized the intergalactic medium surrounding their host galaxies, cleared sightlines along which the light of the young galaxies could escape, and fundamentally altered the physical state of the intergalactic gas in the Universe continuously until the present day 1 , 2 . Observations of the cosmic microwave background 3 , and of galaxies and quasars at the highest redshifts 4 , suggest that the Universe was reionized through a complex process that was completed about a billion years after the Big Bang, by redshift z  ≈ 6. Detecting ionizing Lyman-α photons from increasingly distant galaxies places important constraints on the timing, location and nature of the sources responsible for reionization. Here we report the detection of Lyα photons emitted less than 600 million years after the Big Bang. UDFy-38135539 (ref. 5 ) is at a redshift of z = 8.5549 ± 0.0002, which is greater than those of the previously known most distant objects, at z = 8.2 (refs 6 and 7 ) and z = 6.96 (ref. 8 ). We find that this single source is unlikely to provide enough photons to ionize the volume necessary for the emission line to escape, requiring a significant contribution from other, probably fainter galaxies nearby 9 .

The study investigated the factors that might significantly affect web portal usability. Results of the study were intended to serve as inputs for faculty web portal development of the University of the East-Manila. Descriptive statistics utilized questionnaire data from 82 faculty members. The data showed that most of the respondents were relatively young, were Master's degree holders, were skilled in using the computer and the internet, had internet access at home, and were committed to using the web portal. Respondents perceived that the different web portal design-related factors were moderately evident in the existing faculty web portal. Multiple regression analysis showed that information content as a web portal design-related factor was the only significant predictor of web portal usability. Thus, the null hypothesis stating that faculty-related and web portal design-related factors do not significantly affect faculty web portal usability is accepted except Information Content. The study also discussed the guidelines for web portal developers, as well as the limitations and implications of the study for future research.

This study determined the student profile and enrolment of the three Universities in the University Belt. It also found out the respondents' level of consideration concerning the institutional image indicators that served as basis for attracting prospective entrants. Descriptive statistics revealed the following: most of the respondents belonged to families with five members and lived in family-owned houses in the cities of Manila and Quezon; most of the respondents were taking up Medicine-related courses; most of FEU and UE respondents belonged to less- than-Php 30,000-monthly family income bracket, while UST respondents belonged to greater-than-Php 100,000-monthly family income; and UST had the most number of respondents with family members studying in the same school. A Geographical Information System-generated map also showed that there were more respondents from Marikina than from the nearby municipality of San Juan. For non-Metro Manila settlers, most of the respondents were from the provinces of CALABARZON (Region 4-A) or Central Luzon (Region 3). The three sets of respondents considered five indicators but had different levels of considerations in six indicators. Analysis of variance (ANOVA) showed that five out of six indicators were found to have a significant difference in the level of consideration. Further comparison was utilised through the use of Tukey-HSD. Thus, the hypothesis stating that there is no significant difference in the level of consideration of the respondents from the three Universities regarding institutional-image indicators is partially upheld. [Author abstract, ed]

Candle in the wind Type Ia supernovae are used as cosmological distance indicators. It is through them that the accelerating expansion of the Universe was detected, and with it the implied existence of dark energy. Their presumed reliability as 'standard candles' stems from the fact they have a fixed amount of fuel and a uniform trigger: they are predicted to explode when the mass of the white dwarf nears 1.4 solar masses, the 'Chandrasekhar' mass. Howell et al . now show that the high-redshift supernova SNLS-03D3bb does not play by these rules: its exceptionally high luminosity and low kinetic energy imply a super-Chandrasekhar mass progenitor. So future cosmological studies may need to consider possible contamination from such events when calculating distances. The high-redshift supernova SNLS-03D3bb has an exceptionally high luminosity and low kinetic energy, which both imply a super-Chandrasekhar mass progenitor. The accelerating expansion of the Universe, and the need for dark energy, were inferred from observations 1 , 2 of type Ia supernovae. There is a consensus that type Ia supernovae are thermonuclear explosions that destroy carbon–oxygen white dwarf stars that have accreted matter from a companion star 3 , although the nature of this companion remains uncertain. These supernovae are thought to be reliable distance indicators because they have a standard amount of fuel and a uniform trigger: they are predicted to explode when the mass of the white dwarf nears the Chandrasekhar mass 4 of 1.4 solar masses ( M ⊙ ). Here we show that the high-redshift supernova SNLS-03D3bb has an exceptionally high luminosity and low kinetic energy that both imply a super-Chandrasekhar-mass progenitor. Super-Chandrasekhar-mass supernovae should occur preferentially in a young stellar population, so this may provide an explanation for the observed trend that overluminous type Ia supernovae occur only in ‘young’ environments 5 , 6 . As this supernova does not obey the relations that allow type Ia supernovae to be calibrated as standard candles, and as no counterparts have been found at low redshift, future cosmology studies will have to consider possible contamination from such events.

The early and complete temporal characterization of optical, fast, transient sources requires continuous and multiband observations over different timescales (hours to months). For time-domain astronomy, using several telescopes to analyze single objects is the usual method, allowing the acquisition of highly sampled light curves. Taking a series of images each night helps to construct an uninterrupted chain of observations with a high cadence and low duty cycle. Speed is paramount, especially at early times, in order to capture early features in the light curve that help determine the nature of the observed transients and assess their astrophysical properties. However, the problem of rapidly extracting source properties (temporal and color evolution) with a heterogeneous data set remains. Consequently, we present Muphoten, a general and fast-computation photometric pipeline able to address these constraints. It is suitable for extracting transient brightness over multitelescope and multiband networks to create a single homogeneous photometric time series. We show the performance of Muphoten with observations of the optical transient SN 2018cow (from 2018 June to 2018 July), monitored by the GRANDMA network and with the publicly available data of the Liverpool Telescope.

Active galaxies, especially blazars, are among the most promising extragalactic candidates for high-energy neutrino sources. To date, ANTARES searches included these objects and used GeV–TeV γ-ray flux to select blazars. Here, a statistically complete blazar sample selected by their bright radio emission is used as the target for searches of origins of neutrinos collected by the ANTARES neutrino telescope over 13 yr of operation. The hypothesis of a neutrino–blazar directional correlation is tested by pair counting and a complementary likelihood-based approach. The resulting posttrial p-value is 3.0% (2.2σ in the two-sided convention). Additionally, a time-dependent analysis is performed to search for temporal clustering of neutrino candidates as a means of detecting neutrino flares in blazars. None of the investigated sources alone reaches a significant flare detection level. However, the presence of 18 sources with a pretrial significance above 3σ indicates a p = 1.4% (2.5σ in the two-sided convention) detection of a time-variable neutrino flux. An a posteriori investigation reveals an intriguing temporal coincidence of neutrino, radio, and γ-ray flares of the J0242+1101 blazar at a p = 0.5% (2.9σ in the two-sided convention) level. Altogether, the results presented here suggest a possible connection of neutrino candidates detected by the ANTARES telescope with radio-bright blazars.

A bstract The ANTARES neutrino telescope has an energy threshold of a few tens of GeV. This allows to study the phenomenon of atmospheric muon neutrino disappearance due to neutrino oscillations. In a similar way, constraints on the 3+1 neutrino model, which foresees the existence of one sterile neutrino, can be inferred. Using data collected by the ANTARES neutrino telescope from 2007 to 2016, a new measurement of Δ m 32 2 and θ 23 has been performed — which is consistent with world best-fit values — and constraints on the 3+1 neutrino model have been derived.

Gamma-ray burst host galaxies are deficient in molecular gas, and show anomalous metal-poor regions close to GRB positions. Using recent Australia Telescope Compact Array (ATCA) Hi observations we show that they have substantial atomic gas reservoirs. This suggests that star formation in these galaxies may be fuelled by recent inflow of metal-poor atomic gas. While this process is debated, it can happen in low-metallicity gas near the onset of star formation because gas cooling (necessary for star formation) is faster than the Hi-to-H2 conversion.