Suppressed phase variations in a high amplitude rapidly oscillating Ap star pulsating in a distorted quadrupole mode

We present the results of a multisite photometric observing campaign on the rapidly oscillating Ap (roAp) star 2MASS 16400299-0737293 (J1640; $V=12.7$). We analyse photometric $B$ data to show the star pulsates at a frequency of $151.93$ d$^{-1}$ ($1758.45 \mu$Hz; $P=9.5$ min) with a peak-to-peak amplitude of 20.68 mmag, making it one of the highest amplitude roAp stars. No further pulsation modes are detected. The stellar rotation period is measured at $3.6747\pm0.0005$ d, and we show that rotational modulation due to spots is in anti-phase between broadband and $B$ observations. Analysis and modelling of the pulsation reveals this star to be pulsating in a distorted quadrupole mode, but with a strong spherically symmetric component. The pulsational phase variation in this star is suppressed, leading to the conclusion that the contribution of $\ell>2$ components dictate the shape of phase variations in roAp stars that pulsate in quadrupole modes. This is only the fourth time such a strong pulsation phase suppression has been observed, leading us to question the mechanisms at work in these stars. We classify J1640 as an A7 Vp SrEu(Cr) star through analysis of classification resolution spectra

Instanton operators in five-dimensional gauge theories

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are creditedN.L. is supported in part by STFC grant ST/J002798/1. C.P. is a Royal Society Research Fellow.N.L. is supported in part by STFC grant ST/J002798/1. C.P. is a Royal Society Research Fellow.N.L. is supported in part by STFC grant ST/J002798/1. OPen Aceess funded by SCOAP

A New Near-IR C-2 Linelist for an Improved Chemical Analysis of Hydrogen-deficient, Carbon-rich Giants

Diatomic carbon (C2) is ubiquitous in astronomical environments, from comets and stars to translucent clouds and the interstellar medium. In particular, the C2 bands (mainly the Ballik-Ramsay and Phillips transitions) are an important source of opacity in the near-IR region of carbon stars such as the hydrogen deficient carbon-rich (HdC) or R Coronae Borealis (RCB) stars. Present C2 linelists are still not accurate enough (e.g., in wavelength positions) to model the near-IR spectra of HdC and RCB stars, strongly limiting our ability to properly model their complex spectra and to extract the elemental (an isotopic, when possible) abundances of key elements like C, N, O, F, etc. Very recently, a new near-IR C2 linelist (including both Ballik-Ramsay and Phillips systems, among others) have been generated by the ExoMol project (Yurchenko et al. 2018; see www.exomol.com). The synthetic spectrum constructed for the benchmark HdC star HD 137613, using this new C2 linelist, provides an unprecedented match to its high-resolution (R∼50,000) observed spectrum. The new C2 linelist is thus expected to significantly improve the near-IR chemical analysis for HdC and RCB stars but also for normal carbon stars (e.g., C-rich AGB and dwarf stars) and even Solar System bodies like comets

Observation of interstellar lithium in the low-metallicity Small Magellanic Cloud

The primordial abundances of light elements produced in the standard theory of Big Bang nucleosynthesis (BBN) depend only on the cosmic ratio of baryons to photons, a quantity inferred from observations of the microwave background. The predicted primordial 7Li abundance is four times that measured in the atmospheres of Galactic halo stars. This discrepancy could be caused by modification of surface lithium abundances during the stars' lifetimes or by physics beyond the Standard Model that affects early nucleosynthesis. The lithium abundance of low-metallicity gas provides an alternative constraint on the primordial abundance and cosmic evolution of lithium that is not susceptible to the in situ modifications that may affect stellar atmospheres. Here we report observations of interstellar 7Li in the low-metallicity gas of the Small Magellanic Cloud, a nearby galaxy with a quarter the Sun's metallicity. The present-day 7Li abundance of the Small Magellanic Cloud is nearly equal to the BBN predictions, severely constraining the amount of possible subsequent enrichment of the gas by stellar and cosmic-ray nucleosynthesis. Our measurements can be reconciled with standard BBN with an extremely fine-tuned depletion of stellar Li with metallicity. They are also consistent with non-standard BBN.Comment: Published in Nature. Includes main text and Supplementary Information. Replaced with final title and abstrac

The perturbative partition function of supersymmetric 5D Yang-Mills theory with matter on the five-sphere

Based on the construction by Hosomichi, Seong and Terashima we consider N=1 supersymmetric 5D Yang-Mills theory with matter on a five-sphere with radius r. This theory can be thought of as a deformation of the theory in flat space with deformation parameter r and this deformation preserves 8 supercharges. We calculate the full perturbative partition function as a function of r/g^2, where g is the Yang-Mills coupling, and the answer is given in terms of a matrix model. We perform the calculation using localization techniques. We also argue that in the large N-limit of this deformed 5D Yang-Mills theory this matrix model provides the leading contribution to the partition function and the rest is exponentially suppressed.Comment: 34 pages; v2: typos fixed, matches published version; v3: factor correcte

M5-branes from gauge theories on the 5-sphere

We use the 5-sphere partition functions of supersymmetric Yang-Mills theories to explore the (2,0) superconformal theory on S^5 x S^1. The 5d theories can be regarded as Scherk-Schwarz reductions of the 6d theory along the circle. In a special limit, the perturbative partition function takes the form of the Chern-Simons partition function on S^3. With a simple non-perturbative completion, it becomes a 6d index which captures the degeneracy of a sector of BPS states as well as the index version of the vacuum Casimir energy. The Casimir energy exhibits the N^3 scaling at large N. The large N index for U(N) gauge group also completely agrees with the supergravity index on AdS_7 x S^4.Comment: 44 pages, 1 figure, v4: ref added, clarified weak/strong coupling behaviors of large N free energy, minor improvements, version to be published in JHE

Near-source passive sampling for monitoring viral outbreaks within a university residential setting

\ua9 2024 Cambridge University Press. All rights reserved. Wastewater based epidemiology (WBE) has proven to be a powerful tool for the population-level monitoring of pathogens, particularly SARS-CoV-2. For accurate and timely assessment, several wastewater sampling regimes and methods of viral concentration have been investigated, mainly targeting SARS-CoV-2. However, the use of passive samplers in near-source environments for a range of viruses in wastewater is yet under-investigated. To address this, near-source passive samples were taken at four locations targeting student halls of residence. These were chosen as an exemplar due to their high population density and perceived risk of disease transmission. Viruses investigated were SARS-CoV-2 and its variants of concern (VOCs), influenza-A and B viruses and enteroviruses. Sampling was conducted either in the morning, where passive samplers were in place overnight (17 h) and during the day, where samplers remained in the sewer for 7 h. We demonstrated the usefulness of near-source passive sampling for the detection of VOCs using qPCR and Next Generation Sequencing. Furthermore, several outbreaks of influenza-A and sporadic outbreaks of enteroviruses (some associated with enterovirus D68 and coxsackieviruses) were identified amongst the resident student population, providing evidence of the usefulness of near-source, in-sewer sampling for monitoring the health of high population density communities

Queering identity : becoming queer in the work of Cassils

This chapter explores the work of genderqueer artist Cassils in order to address the question of what it is to be human from a queer perspective. The challenges from queer and postmodern scholarship to the “identity politics” so central to earlier activist and academic agendas have been well documented. Yet, notwithstanding these valid critiques, identity remains a powerful organizing concept in contemporary experience. These contradictory stances on identity serve as a prompt for thinking about what queer brings to our understandings of being human now and in the near future

The temperature and chronology of heavy-element synthesis in low-mass stars

Roughly half of the heavy elements (atomic mass greater than that of iron) are believed to be synthesized in the late evolutionary stages of stars with masses between 0.8 and 8 solar masses. Deep inside the star, nuclei (mainly iron) capture neutrons and progressively build up (through the slow-neutron-capture process, or s-process) heavier elements that are subsequently brought to the stellar surface by convection. Two neutron sources, activated at distinct temperatures, have been proposed: 13C and 22Ne, each releasing one neutron per alpha-particle (4He) captured. To explain the measured stellar abundances, stellar evolution models invoking the 13C neutron source (which operates at temperatures of about one hundred million kelvin) are favoured. Isotopic ratios in primitive meteorites, however, reflecting nucleosynthesis in the previous generations of stars that contributed material to the Solar System, point to higher temperatures (more than three hundred million kelvin), requiring at least a late activation of 22Ne. Here we report a determination of the s-process temperature directly in evolved low-mass giant stars, using zirconium and niobium abundances, independently of stellar evolution models. The derived temperature supports 13C as the s-process neutron source. The radioactive pair 93Zr-93Nb used to estimate the s-process temperature also provides, together with the pair 99Tc-99Ru, chronometric information on the time elapsed since the start of the s-process, which we determine to be one million to three million years.Comment: 30 pages, 10 figure

Phases of planar 5-dimensional supersymmetric Chern-Simons theory

In this paper we investigate the large-$N$ behavior of 5-dimensional $\mathcal{N}=1$ super Yang-Mills with a level $k$ Chern-Simons term and an adjoint hypermultiplet. As in three-dimensional Chern-Simons theories, one must choose an integration contour to completely define the theory. Using localization, we reduce the path integral to a matrix model with a cubic action and compute its free energy in various scenarios. In the limit of infinite Yang-Mills coupling and for particular choices of the contours, we find that the free-energy scales as $N^{5/2}$ for $U(N)$ gauge groups with large values of the Chern-Simons 't\,Hooft coupling, $\tilde\lambda\equiv N/k$. If we also set the hypermultiplet mass to zero, then this limit is a superconformal fixed point and the $N^{5/2}$ behavior parallels other fixed points which have known supergravity duals. We also demonstrate that $SU(N)$ gauge groups cannot have this $N^{5/2}$ scaling for their free-energy. At finite Yang-Mills coupling we establish the existence of a third order phase transition where the theory crosses over from the Yang-Mills phase to the Chern-Simons phase. The phase transition exists for any value of $\tilde\lambda$, although the details differ between small and large values of $\tilde\lambda$. For pure Chern-Simons theories we present evidence for a chain of phase transitions as $\tilde\lambda$ is increased. We also find the expectation values for supersymmetric circular Wilson loops in these various scenarios and show that the Chern-Simons term leads to different physical properties for fundamental and anti-fundamental Wilson loops. Different choices of the integration contours also lead to different properties for the loops.Comment: 40 pages, 17 figures, Minor corrections, Published versio