@inproceedings{21565,
  abstract     = {Dielectric resonators are open systems whose eigenmodes couple to the radiation continuum resulting in nonzero radiation losses. For a long time, it was believed that only guided modes with frequencies below the light line were decoupled from the radiation continuum [1] . In the early 2000’s, several counterexamples of perfectly localized states – i.e. totally decoupled from the radiation continuum – at frequencies above the light line were proposed in dielectric gratings and photonic crystal waveguides [2] . Such states are known as bound states in the continuum (BIC) .},
  author       = {Sidorenko, M. S. and Sergaeva, O. N. and Sadrieva, Z. F. and Roques-Carmes, Charles and Muraev, P. S. and Maksimov, D. N. and Bogdanov, A. A.},
  booktitle    = {2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference},
  location     = {Munich, Germany},
  publisher    = {IEEE},
  title        = {{Accidental bound state in the continuum in a chain of dielectric disks}},
  doi          = {10.1109/cleo/europe-eqec52157.2021.9592618},
  year         = {2021},
}

@inproceedings{21574,
  abstract     = {Combinatorial problems, such as the Ising problem, are hard to solve with conventional electronics. Photonic systems have recently been proposed as an efficient platform to solve these problems faster and more efficiently, thus calling for the development of featured algorithms to run on photonic machines. A few recent findings, including the Photonic Recurrent Ising Sampler, a photonic machine that recurrently solves arbitrary Ising problems, will be presented in this talk, along with their experimental realizations in various platforms.},
  author       = {Roques-Carmes, Charles and Shen, Yichen and Prabhu, Mihika and Englund, Dirk and Joannopoulos, John and Soljacic, Marin},
  booktitle    = {AI and Optical Data Sciences II},
  location     = {Virtual},
  publisher    = {SPIE},
  title        = {{Heuristic algorithms to solve combinatorial problems with photonics}},
  doi          = {10.1117/12.2579334},
  volume       = {11703},
  year         = {2021},
}

@inproceedings{21575,
  abstract     = {Periodic wavelength-scale surface patterns have long been used in the context of lasing and spontaneous emission to enhance emission by light trapping (distributed Bragg resonances). Buried within these well-known devices, however, are theoretical mysteries that are still being unravelled. A periodic surface grating actually creates a continuum of resonant modes, so what determines which single mode (if any) lases? Technically, what determines the stability of a periodic lasing mode: is it only the finite size of a surface that allows single-mode lasing, or can it arise for arbitrarily large structures? More generally, if one continuously deforms an unpatterned surface to maximize light emission, how is the symmetry broken and what optimal structures arise? We address these questions by combining new computational techniques for modeling and large-scale optimization of incoherent emission and lasing with new analytical results arising from perturbation and stability theory.},
  author       = {Benzaouia, Mohammed and Yao, Wenjie and Cerjan, Alexander and Lin, Zin and Roques-Carmes, Charles and Verdugo, Francesc and Christiansen, Rasmus E. and Johnson, Steven G.},
  booktitle    = {Active Photonic Platforms XIII},
  location     = {San Diego, CA, United States},
  pages        = {117960L},
  publisher    = {SPIE},
  title        = {{Foundations of lasing and emission from surface-patterned structures}},
  doi          = {10.1117/12.2595792},
  volume       = {11796},
  year         = {2021},
}

@inproceedings{21622,
  abstract     = {We develop a general framework to describe non-equilibrium radiation by materials in nanophotonic structures (such as photoluminescence/cathodoluminescence/scintillation). We demonstrate the concept experimentally, enhancing and shaping cathodoluminescence from a silica photonic crystal.},
  author       = {Roques-Carmes, Charles and Rivera, Nicholas and Ghorashi, Ali and Kooi, Steven E. and Yang, Yi and Lin, Zin and Beroz, Justin and Joannopoulos, John D. and Kaminer, Ido and Johnson, Steven and Soljačić, Marin},
  booktitle    = {Conference on Lasers and Electro-Optics},
  location     = {San Jose, CA, United States},
  publisher    = {Optica Publishing Group},
  title        = {{A general framework for shaping luminescence in materials}},
  doi          = {10.1364/cleo_qels.2021.fm1l.5},
  year         = {2021},
}

@inproceedings{21623,
  abstract     = {We present a method to overcome the Manley-Rowe limit in a <jats:italic>Q</jats:italic>-factor engineered multimodal nonlinear cavity. Cascading nonlinear processes enable continuous-wave terahertz generation with a theoretical conversion efficiency of 98.8%.},
  author       = {Salamin, Yannick and Roques-Carmes, Charles and Lin, Zin and Johnson, Steven G. and Soljačić, Marin},
  booktitle    = {Conference on Lasers and Electro-Optics},
  location     = {San Jose, CA, United States},
  publisher    = {Optica Publishing Group},
  title        = {{Overcoming the Manley-Rowe limit for CW terahertz generation in Q-engineered multimodal cavity}},
  doi          = {10.1364/cleo_qels.2021.ftu2j.3},
  year         = {2021},
}

@article{21805,
  abstract     = {Donor–acceptor Stenhouse adducts (DASAs) are visible‐light‐responsive photoswitches with a variety of emerging applications in photoresponsive materials. Their two‐step modular synthesis, centered on the nucleophilic ring opening of an activated furan, makes DASAs readily accessible. However, the use of less reactive donors or acceptors renders the process slow and low yielding, which has limited their development. We demonstrate here that 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) promotes the ring‐opening reaction and stabilizes the open isomer, allowing greatly reduced reaction times and increased yields for known derivatives. In addition, it provides access to previously unattainable DASA‐based photoswitches and DASA–polymer conjugates. The role of HFIP and the photochromic properties of a set of new DASAs is probed using a combination of <jats:sup>1</jats:sup>H NMR and UV/Vis spectroscopy. The use of sterically hindered, electron‐poor amines enabled the dark equilibrium to be decoupled from closed‐isomer half‐lives for the first time.},
  author       = {Clerc, Michèle and Stricker, Friedrich J and Ulrich, Sebastian and Sroda, Miranda and Bruns, Nico and Boesel, Luciano F. and Read de Alaniz, Javier},
  issn         = {1521-3773},
  journal      = {Angewandte Chemie International Edition},
  number       = {18},
  pages        = {10219--10227},
  publisher    = {Wiley},
  title        = {{Promoting the furan ring‐opening reaction to access new donor-acceptor Stenhouse adducts with hexafluoroisopropanol}},
  doi          = {10.1002/anie.202100115},
  volume       = {60},
  year         = {2021},
}

@article{21808,
  abstract     = {A convenient approach for the synthesis of foldable redox-active flavin peptide conjugates was established. A model β-hairpin oligopeptide motif was utilized to demonstrate that azidolysine side-chains are readily functionalised with an alkyne-bearing flavine derivative. The folding equilibrium of the peptide backbone as well as the redox behaviour of the flavin moieties remains intact after the conjugation.},
  author       = {Stricker, Friedrich J and Kölsch, Jonas Christopher and Beil, Sebastian B. and Preiß, Sebastian and Waldvogel, Siegfried R. and Opatz, Till and Besenius, Pol},
  issn         = {1477-0539},
  journal      = {Organic & Biomolecular Chemistry},
  number       = {20},
  pages        = {4483--4486},
  publisher    = {Royal Society of Chemistry},
  title        = {{Facile access to foldable redox-active flavin-peptide conjugates}},
  doi          = {10.1039/d1ob00414j},
  volume       = {19},
  year         = {2021},
}

@article{21811,
  abstract     = {The effects of solution‐state dielectric and intermolecular interactions on the degree of charge separation provide a route to understanding the switching properties and concentration dependence of donor–acceptor Stenhouse adducts (DASAs). Through solvatochromic analysis of the open‐form DASA in conjunction with X‐ray diffraction and computational theory, we have analyzed the ionic character of a series of DASAs. First‐ and third‐generation architectures lead to a higher zwitterionic resonance contribution of the open form and a zwitterionic closed form, whereas the second‐generation architecture possesses a less charge‐separated open form and neutral closed form. This can be correlated with equilibrium control and photoswitching solvent compatibility. As a result of the high contribution of the zwitterionic resonance forms of first‐ and third‐generation DASAs, we were able to control their switching kinetics by means of ion concentration, whereas second‐generation DASAs were less affected. Importantly, these results show how the previously reported concentration dependence of DASAs is not universal, and that DASAs with a more hybrid structure in the open form can achieve photoswitching at high concentrations.},
  author       = {Sroda, Miranda M. and Stricker, Friedrich J and Peterson, Julie A. and Bernal, Alexandria and Read de Alaniz, Javier},
  issn         = {1521-3765},
  journal      = {Chemistry - A European Journal},
  number       = {12},
  pages        = {4183--4190},
  publisher    = {Wiley},
  title        = {{Donor–acceptor Stenhouse adducts: Exploring the effects of ionic character}},
  doi          = {10.1002/chem.202005110},
  volume       = {27},
  year         = {2021},
}

@article{21816,
  abstract     = {A new Diels−Alder (DA)-based photopatterning platform is presented, which exploits the irreversible, light-induced decarbonylation and subsequent cleavage of cyclopentadienone−norbornadiene (CPD−NBD) adducts. A series of CPD−NBD adducts have been prepared and systematically studied toward the use in a polymeric material photopatterning platform. By incorporating an optimized CPD−NBD adduct into polymer networks, it is demonstrated that cyclopentadiene may be unveiled upon 365 nm irradiation and subsequently clicked to a variety of maleimides with spatial control under mild reaction conditions and with fast kinetics. Unlike currently available photoinduced Diels−Alder reactions that rely on trapping transient, photocaged dienes, this platform introduces a persistent, yet highly reactive diene after irradiation, enabling the use of photosensitive species such as cyanine dyes to be patterned. To highlight the potential use of this platform in a variety of material applications, we demonstrate two proof-of-concepts: patterned conjugation of multiple dyes into apolyacrylate network and preprogrammed ligation of streptavidin into poly(ethylene glycol) hydrogels.},
  author       = {Bailey, Sophia J. and Stricker, Friedrich J and Hopkins, Erik and Wilson, Maxwell Z. and Read de Alaniz, Javier},
  issn         = {1944-8252},
  journal      = {ACS Applied Materials & Interfaces},
  keywords     = {click chemistry, Diels−Alder, cyclopentadiene, photochemistry, photopatterning},
  number       = {30},
  pages        = {35422--35430},
  publisher    = {American Chemical Society},
  title        = {{Shining light on cyclopentadienone–norbornadiene Diels-Alder adducts to enable photoinduced click chemistry with cyclopentadiene}},
  doi          = {10.1021/acsami.1c08670},
  volume       = {13},
  year         = {2021},
}

@article{21820,
  abstract     = {Photosurfactants have shown considerable promise for enabling stimuli-responsive control of the properties and motion of fluid interfaces. Recently, a number of photoswitch chemistries have emerged to tailor the photoresponsive properties of photosurfactants. However, systematic studies investigating how photoresponsive surfactant behavior depends on the photochemical and photophysical properties of the switch remain scarce. In this work, we develop synthetic schemes and surfactant designs to produce a well-controlled library of photosurfactants to comparatively assess the behavior of photoswitch chemistry on interfacial behavior. We employ photoinduced spreading of droplets at fluid interfaces as a model for such studies. We show that although photosurfactant response is largely guided by expected trends with changes in polarity of the photoswitch, interfacial behavior also depends nontrivially and sometimes counter-intuitively on the kinetics and mechanisms of photoswitching, particularly at the interface of two solvents, as well as on complex interactions with other surfactants. Understanding these complexities enables the design of new photosurfactant systems and their optimization toward responsive functions including triggered spreading, dewetting, and destabilization of droplets on solid and fluid surfaces.},
  author       = {Seshadri, Serena and Bailey, Sophia J. and Zhao, Lei and Fisher, Julia and Sroda, Miranda and Chiu, Michelle and Stricker, Friedrich J and Valentine, Megan T. and Read de Alaniz, Javier and Helgeson, Matthew E.},
  issn         = {1520-5827},
  journal      = {Langmuir},
  number       = {33},
  pages        = {9939--9951},
  publisher    = {American Chemical Society},
  title        = {{Influence of polarity change and photophysical effects on photosurfactant-driven wetting}},
  doi          = {10.1021/acs.langmuir.1c00769},
  volume       = {37},
  year         = {2021},
}

@article{13357,
  abstract     = {Coulombic interactions can be used to assemble charged nanoparticles into higher-order structures, but the process requires oppositely charged partners that are similarly sized. The ability to mediate the assembly of such charged nanoparticles using structurally simple small molecules would greatly facilitate the fabrication of nanostructured materials and harnessing their applications in catalysis, sensing and photonics. Here we show that small molecules with as few as three electric charges can effectively induce attractive interactions between oppositely charged nanoparticles in water. These interactions can guide the assembly of charged nanoparticles into colloidal crystals of a quality previously only thought to result from their co-crystallization with oppositely charged nanoparticles of a similar size. Transient nanoparticle assemblies can be generated using positively charged nanoparticles and multiply charged anions that are enzymatically hydrolysed into mono- and/or dianions. Our findings demonstrate an approach for the facile fabrication, manipulation and further investigation of static and dynamic nanostructured materials in aqueous environments.},
  author       = {Bian, Tong and Gardin, Andrea and Gemen, Julius and Houben, Lothar and Perego, Claudio and Lee, Byeongdu and Elad, Nadav and Chu, Zonglin and Pavan, Giovanni M. and Klajn, Rafal},
  issn         = {1755-4349},
  journal      = {Nature Chemistry},
  keywords     = {General Chemical Engineering, General Chemistry},
  number       = {10},
  pages        = {940--949},
  publisher    = {Springer Nature},
  title        = {{Electrostatic co-assembly of nanoparticles with oppositely charged small molecules into static and dynamic superstructures}},
  doi          = {10.1038/s41557-021-00752-9},
  volume       = {13},
  year         = {2021},
}

@article{13358,
  abstract     = {DNA nanotechnology offers a versatile toolbox for precise spatial and temporal manipulation of matter on the nanoscale. However, rendering DNA-based systems responsive to light has remained challenging. Herein, we describe the remote manipulation of native (non-photoresponsive) chiral plasmonic molecules (CPMs) using light. Our strategy is based on the use of a photoresponsive medium comprising a merocyanine-based photoacid. Upon exposure to visible light, the medium decreases its pH, inducing the formation of DNA triplex links, leading to a spatial reconfiguration of the CPMs. The process can be reversed simply by turning the light off and it can be repeated for multiple cycles. The degree of the overall chirality change in an ensemble of CPMs depends on the CPM fraction undergoing reconfiguration, which, remarkably, depends on and can be tuned by the intensity of incident light. Such a dynamic, remotely controlled system could aid in further advancing DNA-based devices and nanomaterials.},
  author       = {Ryssy, Joonas and Natarajan, Ashwin K. and Wang, Jinhua and Lehtonen, Arttu J. and Nguyen, Minh‐Kha and Klajn, Rafal and Kuzyk, Anton},
  issn         = {1521-3773},
  journal      = {Angewandte Chemie International Edition},
  keywords     = {General Chemistry, Catalysis},
  number       = {11},
  pages        = {5859--5863},
  publisher    = {Wiley},
  title        = {{Light‐responsive dynamic DNA‐origami‐based plasmonic assemblies}},
  doi          = {10.1002/anie.202014963},
  volume       = {60},
  year         = {2021},
}

@article{13359,
  abstract     = {Dissipative self-assembly is ubiquitous in nature, where it gives rise to complex structures and functions such as self-healing, homeostasis, and camouflage. These phenomena are enabled by the continuous conversion of energy stored in chemical fuels, such as ATP. Over the past decade, an increasing number of synthetic chemically driven systems have been reported that mimic the features of their natural counterparts. At the same time, it has been shown that dissipative self-assembly can also be fueled by light; these optically fueled systems have been developed in parallel to the chemically fueled ones. In this perspective, we critically compare these two classes of systems. Despite the complementarity and fundamental differences between these two modes of dissipative self-assembly, our analysis reveals that multiple analogies exist between chemically and light-fueled systems. We hope that these considerations will facilitate further development of the field of dissipative self-assembly.},
  author       = {Weißenfels, Maren and Gemen, Julius and Klajn, Rafal},
  issn         = {2451-9294},
  journal      = {Chem},
  keywords     = {Materials Chemistry, Biochemistry (medical), General Chemical Engineering, Environmental Chemistry, Biochemistry, General Chemistry},
  number       = {1},
  pages        = {23--37},
  publisher    = {Elsevier},
  title        = {{Dissipative self-assembly: Fueling with chemicals versus light}},
  doi          = {10.1016/j.chempr.2020.11.025},
  volume       = {7},
  year         = {2021},
}

@inbook{13360,
  abstract     = {Inorganic nanoparticles (NPs) exhibit a wide range of fascinating physicochemical properties, many of which can be controlled by modulating the NP–NP coupling. Controlling the self-assembly of NPs using light has traditionally been achieved by functionalizing their surfaces with monolayers of photoswitchable molecules, which can be reversibly isomerized between two or more states upon exposure to different wavelengths of light. NPs whose assembly can be controlled by light in a reversible fashion can find interesting applications. The chapter deals with systems comprising mixtures of non-photoswitchable NPs and small-molecule photoacids and photobases. Examples of light-controlled self-assembly of NPs hitherto reported have been categorized into six distinct approaches. These are: functionalizing NPs with monolayers of photoswitchable molecules, light-controlled adsorption/desorption of photoswitchable molecules onto NPs, and light-induced electron transfer between the particle's inorganic core and the NP-bound ligands.},
  author       = {Bian, Tong and Chu, Zonglin and Klajn, Rafal},
  booktitle    = {Out‐of‐Equilibrium (Supra)molecular Systems and Materials},
  editor       = {Giuseppone, Nicolas and Walther, Andreas},
  isbn         = {9783527346158},
  pages        = {241--273},
  publisher    = {Wiley},
  title        = {{Controlling Self‐Assembly of Nanoparticles Using Light}},
  doi          = {10.1002/9783527821990.ch9},
  year         = {2021},
}

@article{13453,
  abstract     = {Most massive stars are born in binaries close enough for mass transfer episodes. These modify the appearance, structure, and future evolution of both stars. We compute the evolution of a 100-day-period binary, consisting initially of a 25 M⊙ star and a 17 M⊙ star, which experiences stable mass transfer. We focus on the impact of mass accretion on the surface composition, internal rotation, and structure of the accretor. To anchor our models, we show that our accretor broadly reproduces the properties of ζ Ophiuchi, which has long been proposed to have accreted mass before being ejected as a runaway star when the companion exploded. We compare our accretor to models of single rotating stars and find that the later and stronger spin-up provided by mass accretion produces significant differences. Specifically, the core of the accretor retains higher spin at the end of the main sequence, and a convective layer develops that changes its density profile. Moreover, the surface of the accretor star is polluted by CNO-processed material donated by the companion. Our models show effects of mass accretion in binaries that are not captured in single rotating stellar models. This possibly impacts the further evolution (either in a binary or as single stars), the final collapse, and the resulting spin of the compact object.},
  author       = {Renzo, M. and Götberg, Ylva Louise Linsdotter},
  issn         = {1538-4357},
  journal      = {The Astrophysical Journal},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics},
  number       = {2},
  publisher    = {American Astronomical Society},
  title        = {{Evolution of accretor stars in massive binaries: Broader implications from modeling ζ Ophiuchi}},
  doi          = {10.3847/1538-4357/ac29c5},
  volume       = {923},
  year         = {2021},
}

@article{13454,
  abstract     = {Helium star–carbon-oxygen white dwarf (CO WD) binaries are potential single-degenerate progenitor systems of thermonuclear supernovae. Revisiting a set of binary evolution calculations using the stellar evolution code MESA, we refine our previous predictions about which systems can lead to a thermonuclear supernova and then characterize the properties of the helium star donor at the time of explosion. We convert these model properties to near-UV/optical magnitudes assuming a blackbody spectrum and support this approach using a matched stellar atmosphere model. These models will be valuable to compare with pre-explosion imaging for future supernovae, though we emphasize the observational difficulty of detecting extremely blue companions. The pre-explosion source detected in association with SN 2012Z has been interpreted as a helium star binary containing an initially ultra-massive WD in a multiday orbit. However, extending our binary models to initial CO WD masses of up to 1.2 M⊙, we find that these systems undergo off-center carbon ignitions and thus are not expected to produce thermonuclear supernovae. This tension suggests that, if SN 2012Z is associated with a helium star–WD binary, then the pre-explosion optical light from the system must be significantly modified by the binary environment and/or the WD does not have a carbon-rich interior composition.},
  author       = {Wong, Tin Long Sunny and Schwab, Josiah and Götberg, Ylva Louise Linsdotter},
  issn         = {1538-4357},
  journal      = {The Astrophysical Journal},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics},
  number       = {2},
  publisher    = {American Astronomical Society},
  title        = {{Pre-explosion properties of Helium star donors to thermonuclear supernovae}},
  doi          = {10.3847/1538-4357/ac27ae},
  volume       = {922},
  year         = {2021},
}

@article{13455,
  abstract     = {The majority of massive stars live in binary or multiple systems and will interact with a companion during their lifetimes, which helps to explain the observed diversity of core-collapse supernovae. Donor stars in binary systems can lose most of their hydrogen-rich envelopes through mass transfer. As a result, not only are the surface properties affected, but so is the core structure. However, most calculations of the core-collapse properties of massive stars rely on single-star models. We present a systematic study of the difference between the pre-supernova structures of single stars and stars of the same initial mass (11–21 M⊙) that have been stripped due to stable post-main-sequence mass transfer at solar metallicity. We present the pre-supernova core composition with novel diagrams that give an intuitive representation of the isotope distribution. As shown in previous studies, at the edge of the carbon-oxygen core, the binary-stripped star models contain an extended gradient of carbon, oxygen, and neon. This layer remains until core collapse and is more extended in mass for higher initial stellar masses. It originates from the receding of the convective helium core during core helium burning in binary-stripped stars, which does not occur in single-star models. We find that this same evolutionary phase leads to systematic differences in the final density and nuclear energy generation profiles. Binary-stripped star models have systematically higher total masses of carbon at the moment of core collapse compared to single-star models, which likely results in systematically different supernova yields. In about half of our models, the silicon-burning and oxygen-rich layers merge after core silicon burning. We discuss the implications of our findings for the “explodability”, supernova observations, and nucleosynthesis of these stars. Our models are publicly available and can be readily used as input for detailed supernova simulations.},
  author       = {Laplace, E. and Justham, S. and Renzo, M. and Götberg, Ylva Louise Linsdotter and Farmer, R. and Vartanyan, D. and de Mink, S. E.},
  issn         = {1432-0746},
  journal      = {Astronomy & Astrophysics},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics},
  publisher    = {EDP Sciences},
  title        = {{Different to the core: The pre-supernova structures of massive single and binary-stripped stars}},
  doi          = {10.1051/0004-6361/202140506},
  volume       = {656},
  year         = {2021},
}

@article{13456,
  abstract     = {While most simulations of the epoch of reionization have focused on single-stellar populations in star-forming dwarf galaxies, products of binary evolution are expected to significantly contribute to emissions of hydrogen-ionizing photons. Among these products are stripped stars (or helium stars), which have their envelopes stripped from interactions with binary companions, leaving an exposed helium core. Previous work has suggested these stripped stars can dominate the Lyman Continuum (LyC) photon output of high-redshift, low-luminosity galaxies post-starburst. Other sources of hard radiation in the early universe include zero-metallicity Population iii stars, which may have similar spectral energy distribution (SED) properties to galaxies with radiation dominated by stripped-star emissions. Here, we use four metrics (the power-law exponent over wavelength intervals 240–500 Å, 600–900 Å, and 1200–2000 Å, and the ratio of total luminosity in FUV wavelengths to LyC wavelengths) to compare the SEDs of simulated galaxies with only single-stellar evolution, galaxies containing stripped stars, and galaxies containing Population iii stars, with four different initial mass functions (IMFs). We find that stripped stars significantly alter SEDs in the LyC range of galaxies at the epoch of reionization. SEDs in galaxies with stripped stars have lower power-law indices in the LyC range and lower FUV to LyC luminosity ratios. These differences in SEDs are present at all considered luminosities (${M}_{\mathrm{UV}}\gt -15$, AB system), and are most pronounced for lower-luminosity galaxies. Intrinsic SEDs as well as those with interstellar medium absorption of galaxies with stripped stars and Population iii stars are found to be distinct for all tested Population iii IMFs.},
  author       = {Berzin, Elizabeth and Secunda, Amy and Cen, Renyue and Menegas, Alexander and Götberg, Ylva Louise Linsdotter},
  issn         = {1538-4357},
  journal      = {The Astrophysical Journal},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics},
  number       = {1},
  publisher    = {American Astronomical Society},
  title        = {{Spectral signatures of population III and envelope-stripped stars in galaxies at the epoch of reionization}},
  doi          = {10.3847/1538-4357/ac0af6},
  volume       = {918},
  year         = {2021},
}

@article{13457,
  abstract     = {Context. Observations of massive stars in open clusters younger than ∼8 Myr have shown that a majority of them are in binary systems, most of which will interact during their life. While these can be used as a proxy of the initial multiplicity properties, studying populations of massive stars older than ∼20 Myr allows us to probe the outcome of these interactions after a significant number of systems have experienced mass and angular momentum transfer and may even have merged.

Aims. Using multi-epoch integral-field spectroscopy, we aim to investigate the multiplicity properties of the massive-star population in the dense core of the ∼40 Myr old cluster NGC 330 in the Small Magellanic Cloud in order to search for possible imprints of stellar evolution on the multiplicity properties.

Methods. We obtained six epochs of VLT/MUSE observations operated in wide-field mode with the extended wavelength setup and supported by adaptive optics. We extracted spectra and measured radial velocities for stars brighter than mF814W = 19. We identified single-lined spectroscopic binaries through significant RV variability with a peak-to-peak amplitude larger than 20 km s−1. We also identified double-lined spectroscopic binaries, and quantified the observational biases for binary detection. In particular, we took into account that binary systems with similar line strengths are difficult to detect in our data set.

Results. The observed spectroscopic binary fraction among stars brighter than mF814W = 19 (approximately 5.5 M⊙ on the main sequence) is fSBobs = 13.2 ± 2.0%. Considering period and mass ratio ranges from log(P) = 0.15−3.5 (about 1.4 to 3160 d), q = 0.1−1.0, and a representative set of orbital parameter distributions, we find a bias-corrected close binary fraction of fcl = 34−7+8%. This fraction seems to decline for the fainter stars, which indicates either that the close binary fraction drops in the B-type domain, or that the period distribution becomes more heavily weighted toward longer orbital periods. We further find that both fractions vary strongly in different regions of the color-magnitude diagram, which corresponds to different evolutionary stages. This probably reveals the imprint of the binary history of different groups of stars. In particular, we find that the observed spectroscopic binary fraction of Be stars (fSBobs = 2 ± 2%) is significantly lower than that of B-type stars (fSBobs = 9 ± 2%).

Conclusions. We provide the first homogeneous radial velocity study of a large sample of B-type stars at a low metallicity ([Fe/H] ≲ −1.0). The overall bias-corrected close binary fraction (log(P) < 3.5 d) of the B-star population in NGC 330 is lower than the fraction reported for younger Galactic and Large Magellanic Cloud clusters in previous works. More data are needed, however, to establish whether the observed differences are caused by an age or a metallicity effect.},
  author       = {Bodensteiner, J. and Sana, H. and Wang, C. and Langer, N. and Mahy, L. and Banyard, G. and de Koter, A. and de Mink, S. E. and Evans, C. J. and Götberg, Ylva Louise Linsdotter and Patrick, L. R. and Schneider, F. R. N. and Tramper, F.},
  issn         = {1432-0746},
  journal      = {Astronomy & Astrophysics},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics},
  publisher    = {EDP Sciences},
  title        = {{The young massive SMC cluster NGC 330 seen by MUSE. II. Multiplicity properties of the massive-star population}},
  doi          = {10.1051/0004-6361/202140507},
  volume       = {652},
  year         = {2021},
}

@article{13458,
  abstract     = {Most massive stars experience binary interactions in their lifetimes that can alter both the surface and core structure of the stripped star with significant effects on their ultimate fate as core-collapse supernovae. However, core-collapse supernovae simulations to date have focused almost exclusively on the evolution of single stars. We present a systematic simulation study of single and binary-stripped stars with the same initial mass as candidates for core-collapse supernovae (11–21 M⊙). Generally, we find that binary-stripped stars core tend to have a smaller compactness parameter, with a more prominent, deeper silicon/oxygen interface, and explode preferentially to the corresponding single stars of the same initial mass. Such a dichotomy of behavior between these two modes of evolution would have important implications for supernovae statistics, including the final neutron star masses, explosion energies, and nucleosynthetic yields. Binary-stripped remnants are also well poised to populate the possible mass gap between the heaviest neutron stars and the lightest black holes. Our work presents an improvement along two fronts, as we self-consistently account for the pre-collapse stellar evolution and the subsequent explosion outcome. Even so, our results emphasize the need for more detailed stellar evolutionary models to capture the sensitive nature of explosion outcome.},
  author       = {Vartanyan, David and Laplace, Eva and Renzo, Mathieu and Götberg, Ylva Louise Linsdotter and Burrows, Adam and de Mink, Selma E.},
  issn         = {2041-8213},
  journal      = {The Astrophysical Journal Letters},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics},
  number       = {1},
  publisher    = {American Astronomical Society},
  title        = {{Binary-stripped stars as core-collapse supernovae progenitors}},
  doi          = {10.3847/2041-8213/ac0b42},
  volume       = {916},
  year         = {2021},
}