Search

Ulrike Bialas’ Forever 17 is a beautifully written, theoretically sophisticated, and deeply compassionate look at the lives of young people who have come from a variety of African countries to Germany to start a new life, and how they navigate the legal and categorical barriers to accessing that life. The book is an excellent addition to the migration studies sub-literatures on categorization, labels, and binaries, on the one hand, and the political value of time, on the other hand. [ABSTRACT FROM AUTHOR]

• This study aims to investigate the stability of SX Crv and XX Sex. • The light curves of the SX Crv and XX Sex were carried out in detail. • The orbital period of the XX Sex system was conducted for the first time. • The nature and evolution of SX Crv and XX Sex were discussed. The photometric analyses of the extreme low mass ratio contact binaries SX Crv and XX Sex were conducted in detail. Light curves of SX Crv and XX Sex were retrieved from TESS, and light curve analyses were performed simultaneously with radial velocities. The mass ratios for SX Crv and XX Sex were calculated as 0.077 (1) and 0.099 (2). The masses of the primary components account for about 90 % of the total masses of the systems and were determined to be 1.256 (48) M ⊙ and 1.337 (37) M ⊙ for SX Crv and XX Sex, respectively. It has been observed that the orbital periods of both systems have increased. The orbital period change rate of SX Crv has been calculated to be 0.39 s per century, while that of XX Sex has been calculated to be 2.68 s per century. The orbital angular momentum (J o) determined for both systems is more than 3 times the spin angular momentum (J s), and it can be said that the SX Crv and XX Sex systems are stable. The calculated instability separation (a ins.) and instability mass ratio (q ins.) values for both systems are smaller than those obtained in the analyses, which supports the stability. The estimated ages of the systems are 7.4 Gyr for SX Crv and 3.9 Gyr for XX Sex. logM tot – logJ and logT eff – logL diagrams were also interpreted to better understand the evolution of the extreme low mass ratio contact binaries. [ABSTRACT FROM AUTHOR]

The precessing jets of microquasar SS 433 have punched through the supernova remnant W 50 from the explosion forming the compact object. The jets collimate before reaching beyond the shell, some 40 pc downstream, just the region of origin of TeV gamma radiation. Collimation could be effected by ambient pressure in the SNR cavity; I investigate conditions under which the W 50 morphology and the sites of TeV gamma radiation can be explained in terms of collimation, with associated shocks, induced by ambient pressure. The SNR is now ~ 10 5 years after the supernova; with the present pressure, collimation and associated shocks would indeed occur ~40 pc downstream. Modeling of the evolution of binary systems indicates that the Roche lobe overflow and the initiation of the jets may be recent rather than early; present day collimation would still occur ~40 pc downstream, but the cone angle of the precession must then have increased with time—driven by the Roche lobe overflow. The morphology of W 50 and the site of the origin of TeV radiation are readily explained in terms of the collimation of the jets by internal SNR pressure. [ABSTRACT FROM AUTHOR]

We report on spectroscopic and photometric observations of the AM Canum Venaticorum (AM CVn) system ASASSN-21br, which was discovered in outburst by the All-Sky Automated Survey for Supernovae in 2021 February. The outburst lasted for around three weeks, and exhibited a pronounced brightness dip for |$\approx$| 4 d, during which the spectra showed a sudden transition from emission- to absorption-line dominated. Only |$\approx$| 60 AM CVn systems with derived orbital periods are found in the Galaxy, therefore increasing the sample of AM CVn systems with known orbital periods is of tremendous importance to (1) constrain the physical mechanisms of their outbursts and (2) establish a better understanding of the low-frequency background noise of future gravitational wave surveys. Time-resolved photometry taken during the outburst of ASASSN-21br showed modulation with a period of around 36.65 min, which is likely the superhump or orbital period of the system. Time-resolved spectroscopy taken with the Southern African Large Telescope did not show any sign of periodicity in the He  i absorption lines. This is possibly due to the origin of these lines in the outbursting accretion disc, which makes it challenging to retrieve periodicity from the spectral lines. Future follow-up spectral observations during quiescence might allow us better constrain the orbital period of ASASSN-21br. [ABSTRACT FROM AUTHOR]

Photometric data were used to perform the first light curve analysis of the V0610 Vir binary system. Observations and analysis were done in the form of the Binary Systems of South and North (BSN) Project. We extracted the minima from our observations and compiled the literature, which was few. Therefore, we performed computations using the reference ephemeris and presented a new ephemeris and O-C diagram with a linear fit. Light curve analysis was performed using the PHOEBE Python code and the Markov chain Monte Carlo (MCMC) approach. The assumption of a hot starspot was required due to the asymmetry in the light curve's maxima. The analysis shows that V0610 Vir is a contact binary system with a fillout factor of 0.085, a mass ratio of 0.998, and an inclination of 70°.65. The absolute parameters of the system were estimated based on the Gaia DR3 parallax method. The results show that the system is a low-mass contact binary with a total mass lower than 0.8 M⨀. The location of the stars was shown in the M - L and M - R diagrams. [ABSTRACT FROM AUTHOR]

Flaring in the SS 433 microquasar is dominated by outbursts from material at distances from the centre of mass of the binary system comparable to the separation of the two components. This note completes a demonstration that ejected plasma leaves the system in the region of the L2 point, there overflowing the outer Roche lobe and giving rise to a spiral structure as it leaves the system as part of the local environment. It also provides a new measure of the mass ratio of the binary. [ABSTRACT FROM AUTHOR]

The precessing jets of microquasar SS 433 have punched through the supernova remnant W 50 from the explosion forming the compact object. The jets collimate before reaching beyond the shell, some 40 pc downstream, just the region of origin of TeV gamma radiation. Collimation could be effected by ambient pressure in the SNR cavity; I investigate conditions under which the W 50 morphology and the sites of TeV gamma radiation can be explained in terms of collimation, with associated shocks, induced by ambient pressure. The SNR is now ~105 years after the supernova; with the present pressure, collimation and associated shocks would indeed occur ~40 pc downstream. Modeling of the evolution of binary systems indicates that the Roche lobe overflow and the initiation of the jets may be recent rather than early; present day collimation would still occur ~40 pc downstream, but the cone angle of the precession must then have increased with time—driven by the Roche lobe overflow. The morphology of W 50 and the site of the origin of TeV radiation are readily explained in terms of the collimation of the jets by internal SNR pressure.

Observations of the X-ray binary system Her X-1 by the AstroSat Soft X-ray Telescope (SXT) were carried out in 2020 through 2023 with the goals of measuring X-ray spectrum changes with the 35-day disk precession phase and measuring eclipses at different 35-day phases. Her X-1 exhibits a regular flux modulation with a period of ≃35 days with different intensity levels at various 35-day phases (called "states"). The four multi-day long observations were scheduled to cover most of these states. Each 35-day phase was determined using monitoring observations with the Swift Burst Alert Telescope (BAT). Nine eclipses were observed in the range of 35-day phases, with at least one eclipse during each observation. Data with dips were separated from data without dips. The variation in X-ray spectral parameters vs. 35-day phase shows the following: eclipse parameters are nearly constant, showing that the scattering corona does not change with 35-day phase; dips show an increase in covering fraction but not column density compared to non-dip data; the1 keV line normalization behaves similarly to the powerlaw normalization, consistent with an origin near the powerlaw emission region, likely the magnetospheric accretion flow from the inner disk onto the neutron star; and the blackbody normalization (area) is large ( ∼ 3 × 10 5 km2) during the Main High and Short High states, consistent with the inner edge of the accretion disk. [ABSTRACT FROM AUTHOR]

Although definitions of rural vary across educational research projects and from country to country, an enduring theme has been the framing of rural as a disadvantage or problem that sits alongside a view of the urban as normative. In questioning the urban/rural binary and the deficit discourses that are associated with it, the authors present four short data excerpts and their thinking about how they represent rural education in their research. They conclude that the telling of positive stories about rural education is a move towards changing the discourses that circulate. [ABSTRACT FROM AUTHOR]

A diverse array of families navigate society in current times, yet despite increasing visibility of this diversity within schooling contexts, notions of family as nuclear continue to be (re)produced in these spaces. While this has implications for all children and their families, for gender and sexuality diverse parented families, this state of affairs can create specific challenges. In this article, I draw on conceptualisations of binaries and interpellation to theoretically unpack how family is constructed in schools through ‘mum/dad’ or ‘parent one/parent two’ binaries. The analysis presented provides insights into the normative (re)production of family which has potential to impact on gender and sexuality diverse families and their sense of belonging in schools. In deconstructing ways in which binaries work to (re)produce families in educational contexts, implicit norms are exposed. This provides a critical opening for rethinking ways in which families are constructed through language, discourse, and practice. [ABSTRACT FROM AUTHOR]

We present relative astrometric and photometric measurements of visual double stars made in 2016–2017, with PISCO2 installed at the 76‐cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. Three different techniques were used for obtaining measurements: Lucky Imaging, Speckle Interferometry and the direct vector autocorrelation (DVA) method. From our observations of 1,510 multiple stars, we obtained 2,918 new measurements with angular separations in the range 0″.1–20″ and an average accuracy of 0.019$$ 0.019 $$. The mean error on the position angles is 1°.1. Most of the position angles were determined without the usual 180° ambiguity with the application of the DVA technique and/or by inspection of the Lucky images or the long integration files. We managed to routinely monitor faint systems (mV≈9−12$$ {m}_V\approx 9-12 $$) with large magnitude differences (up to ΔmV≈4.5$$ \Delta {m}_V\approx 4.5 $$). We have thus been able to measure six systems containing red dwarf stars that had been poorly monitored since their discovery, from which we estimated the stellar masses thanks to Gaia measurements. We also measured the magnitude difference of the two components of 593 double stars with a mean error of 0.1 mag. Thanks to good seeing images and with the use of high‐contrast numerical filters, we have also been able to obtain 46 measurements with an angular separation smaller than the diffraction limit of our instrumentation. Except for a few objects that have been discussed, our measurements are in good agreement with the ephemerides computed with published orbital elements, even for the double stars whose separation is smaller than the diffraction limit. We also report the measurements of 205 new double stars that we found in the files obtained during the observations. [ABSTRACT FROM AUTHOR]

New high-precision photometric measurements of the V957 Cep system ( , , , B6 V+B8 V), as well as an integrated approach to determining orbital parameters based both on photometric solutions of the light curves and the study of the course of residual deviations of the minima timings from the linear formula made it possible for the first time to accurately measure the apsidal motion rate: /year, which coincided with the theoretical value under the condition of the orbital and axial rotation synchronism: /year. The physical parameters of the component stars were obtained: K, , , K, M2 = 3.0 ± , . This set of parameters corresponds to stars of zero age, recently descended to ZAMS. The secondary component is a pulsating variable star of the Cephei type. [ABSTRACT FROM AUTHOR]

Since the publication of 'Green Fuse' in The Irish Press in 1974, Éilís Ní Dhuibhne has built up an impressive oeuvre of short fiction. The recent Selected Stories, published by Blackstaff Press in 2023, pays tribute to that achievement. As the collection follows the trajectory of Ní Dhuibhne's career, with two stories from each of her six collections, it allows one to trace both recurring elements and patterns of development in her work. Ní Dhuibhne's sustained exploration of women's lives, dreams and desires, for instance, can be seen to take distinct emphases in each of the collections. This essay argues that binary oppositions are used as structuring models in Ní Dhuibhne's first four collections – in juxtaposed plotlines, stories and endings as well as contrasting characters, places and times – but, in her later collections, these oppositions move to the more subjective realm of inner reflection and imagination. [ABSTRACT FROM AUTHOR]

We have determined the mass functions, mass-ratio distribution functions, and fractions of binary stars with mass ratios above particular thresholds for radially separated populations of stars in the nearby open clusters Hyades and Praesepe. Radial mass segregation is detected, with the populations of stars within the tidal radii having much flatter mass functions than those outside the tidal radii. Within the tidal radii, the frequency of binary stars with mass ratio q > 0.5 is 50–75 per cent higher for Hyades and 5–30 per cent higher for Praesepe. We also, for the first time, detect mass-ratio radial segregation. Of the binaries for which q > 0.5, ∼80 per cent of the inner Hyades population also have q > 0.75, while for the extra-tidal population, the ratio is ∼50 per cent. For Praesepe, ∼67 per cent of the inner sample have q > 0.75, and 35–45 per cent of the outer sample. [ABSTRACT FROM AUTHOR]

Previous work has shown that interactions between a central binary system and a circumbinary disc (CBD) can lead to the binary orbit either shrinking or expanding, depending on the properties of the disc. In this work, we perform two-dimensional hydrodynamical simulations of CBDs surrounding equal mass binary systems that are on fixed circular orbits, using the athena ++ code in Cartesian coordinates. Previous studies have focused on discs where viscosity drives angular momentum transport. The aim of this work is to examine how the evolution of a binary system changes when angular momentum is extracted from the disc by a magnetized wind. In this proof-of-concept study, we mimic the effects of a magnetic field by applying an external torque that results in a prescribed radial mass flux through the disc. For three different values of the radial mass flux, we compare how the binary system evolves when the disc is either viscous or wind driven. In all cases considered, our simulations predict that the binary orbit should shrink faster by a factor of a few when surrounded by a wind-driven CBD compared to a corresponding viscous CBD. In-spiral time-scales of ∼106–107 yr are obtained for circular binaries surrounded by CBDs with masses typical of protoplanetary discs, indicating that significant orbital shrinkage can occur through binary–disc interactions during Class I/II pre-main-sequence phases. [ABSTRACT FROM AUTHOR]

Accretion is a universal astrophysical process that plays a key role in cosmic history, from the epoch of reionization to galaxy and stellar formation and evolution. Accreting stellar-mass black holes in X-ray binaries are one of the best laboratories to study the accretion process and probe strong gravity--and most importantly, to measure the angular momentum, or spin, of black holes, and its role as a powering mechanism for relativistic astrophysical phenomena. Comprehensive characterization of the disk-corona system of accreting black holes, and their co-evolution, is fundamental to measurements of black hole spin. Here, we use simulated data to demonstrate how key unanswered questions in the study of accreting stellar-mass black holes will be addressed by the High Energy X-ray Probe (HEX-P). HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging and broad spectral coverage (0.2-80 keV) with a sensitivity superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. We illustrate the capability of HEX-P to: 1) measure the evolving structures of black hole binary accretion flows down to low (≲ 0.1%) Eddington-scaled luminosities via detailed X-ray reflection spectroscopy; 2) provide unprecedented spectral observations of the coronal plasma, probing its elusive geometry and energetics; 3) perform detailed broadband studies of stellar mass black holes in nearby galaxies, thus expanding the repertoire of sources we can use to study accretion physics and determine the fundamental nature of black holes; and 4) act as a complementary observatory to a range of future ground and space-based astronomical observatories, thus providing key spectral measurements of the multi-component emission from the inner accretion flows of black hole X-ray binaries. [ABSTRACT FROM AUTHOR]

We analyze photometric observations of the symbiotic star MWC 560 in B and V bands obtained during the period 1990-2023. We estimate the luminosity and the mass accretion rate of the hot component. We find that the luminosity varies in the range from 200 L to 3000 L, corresponding to a mass accretion rate in the range 1 x 10-7-2x 10-6 M⊙ yr-1 (for a 0.9 M white dwarf and distance 2217 pc). The optical flickering disappears at mass accretion rate of about 1 x 10-6 M⊙ yr-¹, which sets an upper limit for the short-term variability from accreting white dwarf. [ABSTRACT FROM AUTHOR]

The cataclysmic variable Nova Cas 2021, also known as V1405 Cas, exploded as a nova on March 18, 2021. Here we report the results of our optical spectroscopic monitoring that lasted from late 2021 to early 2023 and was conducted using the 0.4 m telescope at the University of Jaén observatory. These data are intended to contribute to the observational coverage of the nova spectral evolution, both in the permitted line and nebular phases. The development of high ionization conditions could be followed through the progression of the Bowen blend, He II and C IV emission features. Hydrogen lines were also studied in an attempt to disentangle the late ejecta components and estimate their total mass. Finally, the neon stage of V1405 Cas is suspected to have occurred earlier than previous reports. [ABSTRACT FROM AUTHOR]

Contact binaries are close binary systems in which both components fill their inner Roche lobes so that the stars are in direct contact, and in potential mass and energy exchange. The most common such systems of low mass are the so-called W UMa-type. In the last few years, there has been a growing interest of the astronomical community in stellar mergers, primarily due to the detection of gravitational waves (mergers of black holes and neutron stars), but also because of an alternative model for the type Ia supernovae (merger of two white dwarfs), which are again particularly important in cosmology where they played a significant role in the discovery of dark energy and the accelerated expansion of the Universe. In that sense, contact systems of W UMa type with extremely low mass ratio are especially interesting because there are indications that, in their case too, stars can merge and possibly form fast-rotating stars such as FC Com stars and the blue-stragglers, and (luminous) red novae such as V1309 Sco. Namely, the previous theoretical research has shown that in the cases when the orbital angular momentum of the system is only about three times larger than the rotational angular momentum of the primary, a tidal Darwin's instability occurs, the components can no longer remain in synchronous rotation, orbit continue to shrink fast, and they finally merge into a single star. The above stability condition for contact systems can be linked to a specific critical mass ratio below which we expect a system to be unstable. We give an overview of this condition and show how it can be used to identify potential mergers. Finally, we discuss a number of known extreme mass ratio binaries from the literature and consider prospects for future research on this topic. [ABSTRACT FROM AUTHOR]

We performed optical photometry and spectral observations of the symbiotic stars 4U1954-∣-319 and ZZ CMi. For 4U1954±319, using high-resolution spectra, we, measure the equivalent widths of diffuse interstellar bands (DIBs) and estimatethe interstellar reddening E(B-V) = 0.83±0.09. Using the GAIA distances and our photometry, we find: (1) the absolute V-band magnitude My = --5.23 ± 0.08 of 4U1954±319 and that the mass donor is a supergiant of luminosity class lb, and (2) My = --0.27 ±0.2 for ZZ CMi and that the mass donor is a giant of luminosity class III. [ABSTRACT FROM AUTHOR]

This report presents a comprehensive analysis of the spectral and temporal characteristics of a highly significant Ultra- luminous X-ray Source (ULX) designated as CXOUJ122956.7+075728 (ULX-1) situated in the elliptical galaxy NGC 4472 within the Virgo cluster. ULX-1 exhibits a soft spectral state, featuring a cool accretion disk component with kTin - 0.15 keV, accompanied by a power-law tail displaying a steep power-law photon index, Γ - 2.8. The spectral findings strongly support an estimated black hole mass of approximately 3.30 x 10³ M⊗ under an isotropic emission model, and around 1.47 x 10³ M⊗ in an extreme beaming scenario. Temporally, ULX-1 displays significant variability on time scales of 0.5, 1, and 2 ks, suggesting the possibility of instabilities within the accretion disk contributing to this behavior. However, despite this temporal variability, the power spectra analysis of this soft ULX reveals no signatures of pulsations, distinguishing it from certain pulsating ULXs (PULXs) typically associated with neutron stars. This absence of pulsations in ULX-1 further underscores its unique spectral and temporal characteristics within the broader context of ULX phenomena. [ABSTRACT FROM AUTHOR]

The origin of the spins of stellar-mass black holes is still controversial, and angular momentum transport inside massive stars is one of the main sources of uncertainty. Here, we apply hierarchical Bayesian inference to derive constraints on spin models from the 59 most confident binary black hole merger events in the third gravitational-wave transient catalogue (GWTC-3). We consider up to five parameters: chirp mass, mass ratio, redshift, effective spin, and precessing spin. For the model selection, we use a set of binary population synthesis simulations spanning drastically different assumptions for black hole spins and natal kicks. In particular, our spin models range from the maximal to minimal efficiency of angular momentum transport in stars. We find that if we include the precessing spin parameter into our analysis, models predicting only vanishingly small spins are in tension with GWTC-3 data. On the other hand, models in which most spins are vanishingly small but that also include a subpopulation of tidally spun-up black holes are a good match to the data. Our results show that the precessing spin parameter has a crucial impact on model selection. [ABSTRACT FROM AUTHOR]

We performed the first photometric study of the CSS J003106.8+313347 W Ursae Majoris (WUMa)-type system based on ground-based observations. We extracted times of minima from our observations and proposed a linear ephemeris based on the increasing incline of the orbital period using a Markov chain Monte Carlo (MCMC) approach. The PHOEBE Python code and the MCMC approach were used for the light curve analysis. This system did not need starspots for the light curve analysis. Mass ratio, fillout factor, and inclination were obtained as 0.699, 0.322, and 60°.6 respectively. We also estimated the absolute parameters of the system using the Gaia DR3 parallax. Therefore, the masses, radii, and luminosities have been determined to be M1 = 1.675, M2 = 1.171, R1 = 1.292, R2 = 1.097, L1 = 1.348, and L2 = 1.221. The orbital angular momentum J0 of the CSS J003106.8+313347 illustrates that this system is located in a region of contact binaries. The positions of the primary and secondary components on the Hertzsprung-Russell (HR) diagram are depicted. [ABSTRACT FROM AUTHOR]

We present relative astrometric and photometric measurements of visual double stars made in 2013–2015, with PISCO2 installed at the 76‐cm refractor of Côte d'Azur Observatory in Nice (France). Our observing list contains orbital couples as well as double stars whose motion is still uncertain. Most of the observations were done in 2015, but some other observations of wide couples were done in 2013–2014 (0.3% of the total of the observations). Three different techniques were used for obtaining measurements: lucky imaging, speckle interferometry and the direct vector autocorrelation method. From our observations of 2837 multiple stars, we obtained 5182 new measurements with angular separations in the range of 0″$$ {}^{{\prime\prime} } $$.1–32″$$ {}^{{\prime\prime} } $$ and an average accuracy of 0″.018$$ {0}^{{\prime\prime} }.018 $$. The mean error on the position angles is 0°.8. Most of the position angles were determined without the usual 180° ambiguity with the application of the direct vector autocorrelation technique and/or by inspection of the Lucky images or the long integration files. We managed to routinely monitor faint systems (mV≈9−11$$ {m}_V\approx 9-11 $$) with large magnitude difference (up to ΔmV≈4.5$$ \Delta {m}_V\approx 4.5 $$). We have thus been able to measure 21 systems containing red dwarf stars that had been poorly monitored since their discovery, from which we estimated the stellar masses thanks to Gaia measurements. We also measured the magnitude difference of the two components of 1079 double stars with an estimated error of 0.2 mag. Except for a few objects that are discussed, our measurements are in good agreement with the ephemerides computed with published orbital elements, even for the double stars whose separation is smaller than the diffraction limit. Thanks to good seeing images and with the use of high‐contrast numerical filters, we have also been able to obtain 196 measurements with an angular separation smaller than the diffraction limit of our instrumentation, and consistent with those obtained with larger telescopes. We also report measurements of the 164 new double stars that we found in the files obtained during the observations. Finally, from a study of the DR3 Gaia release, it is shown that all the objects of the Tycho Double Star Catalog that we did not resolve in 2015 are probably false detections by Tycho. [ABSTRACT FROM AUTHOR]

This paper investigates the (de)construction of binaries vis-à-vis the verticality of women in domestic and epistemic domains in Nayomi Munaweera's Island of a Thousand Mirrors. In doing so, the study employs Greeta Gaard's concept of naturalization of women and feminization of nature which refer to the process of using binaries as a means to ensure that women remain on a horizontal position in the vertically moving structure of power. Being in a horizontal position, both women and nature are not powerful. Through this theoretical lens, this study explores the reasons of horizontality by investigating the patriarchal thoughts of society that categorize women as aquatic, domestic and wild animals through the use of animalistic language to show their restricted movement. The animalization reflects the subjugation of women in the hands of capitalist man. The study also focuses on feminization of nature which is feminized because of its caring and reproductive attributes. These shared attributes allow patriarchal ideologies to dominate women and nature through oppressive strategies. The discussion on animalization and naturalization underscores the constraints imposed on women and their mobility within sociocultural context. Furthermore, this paper takes into consideration the traumatic experiences, sufferings and exploitation of rape victims and highlights how female characters break the societal sanctions, and resurface in order to move vertically while deconstructing the binaries of male-female, Sinhala-Tamil, and human-nonhuman. The deconstruction of binaries creates an inclusive society without discrimination of the oppressed and the privileged. It also highlights that we need to treat all living creatures equally with compassion. I use Catherine Belsey's method of textual analysis in order to analyze the selected text. [ABSTRACT FROM AUTHOR]

We use a catalogue of stellar binaries with wide separations (up to 1 pc) identified by the Gaia satellite to constrain the presence of extended substructure within the Milky Way galaxy. Heating of the binaries through repeated encounters with substructure results in a characteristic distribution of binary separations, allowing constraints to be placed independent of the formation mechanism of wide binaries. Across a wide range of subhalo density profiles, we show that subhaloes with masses |$\gtrsim 65\, \mathrm{ M}_\odot$| and characteristic length scales similar to the separation of these wide binaries cannot make up 100 per cent of the Galaxy's dark matter. Constraints weaken for subhaloes with larger length scales and are dependent on their density profiles. For such large subhaloes, higher central densities lead to stronger constraints. Subhaloes with density profiles similar to those expected from cold dark matter must be at least ∼5000 times denser than predicted by simulation to be constrained by the wide binary catalogue. [ABSTRACT FROM AUTHOR]

Reality and fiction build a binary which shared the fate of dualist thinking in general in the postmodernist age, dominated by deconstruction. The climactic point was probably reached by the fabrication of lens which magnify reality. The fabrication of virtual reality lens was meant to augment reality, virtual reality meaning less or a deformed reality show. Science and technology have thus reified the philosophical battle over positivist taxonomies and classifications that first came under the philosophical onslaught of Søren Kierkegaard and Friedrich Nietzsche. The “either/ or” dichotomy of the former ended up in the latter’s “beyond”, which, in quantum language, is a superposition of opposite states. Although the bulk of fantasy and science-fiction still capitalizes on the distinct ontologies of reality and fiction, the literature of late modernity (modernism and postmodernism) speculated on an ontological hybrid bridging the ontological gap between the two of them. Such are the modernist novel, “Isabel and the Devil’s Waters” by Mircea Eliade, and the postmodernist story, “Schrödinger’s Cat,” by Ursula K. Le Guin read in the key of an ontological poetics in the present paper.

Flaring in the SS 433 microquasar is dominated by outbursts from material at distances from the centre of mass of the binary system comparable to the separation of the two components. This note completes a demonstration that ejected plasma leaves the system in the region of the L2 point, there overflowing the outer Roche lobe and giving rise to a spiral structure as it leaves the system as part of the local environment. It also provides a new measure of the mass ratio of the binary.

Observations of the X-ray binary system Her X-1 by the AstroSat Soft X-ray Telescope (SXT) were carried out in 2020 through 2023 with the goals of measuring X-ray spectrum changes with the 35-day disk precession phase and measuring eclipses at different 35-day phases. Her X-1 exhibits a regular flux modulation with a period of ≃35 days with different intensity levels at various 35-day phases (called “states”). The four multi-day long observations were scheduled to cover most of these states. Each 35-day phase was determined using monitoring observations with the Swift Burst Alert Telescope (BAT). Nine eclipses were observed in the range of 35-day phases, with at least one eclipse during each observation. Data with dips were separated from data without dips. The variation in X-ray spectral parameters vs. 35-day phase shows the following: eclipse parameters are nearly constant, showing that the scattering corona does not change with 35-day phase; dips show an increase in covering fraction but not column density compared to non-dip data; the1 keV line normalization behaves similarly to the powerlaw normalization, consistent with an origin near the powerlaw emission region, likely the magnetospheric accretion flow from the inner disk onto the neutron star; and the blackbody normalization (area) is large (∼3×105 km2) during the Main High and Short High states, consistent with the inner edge of the accretion disk.

Accretion is a universal astrophysical process that plays a key role in cosmic history, from the epoch of reionization to galaxy and stellar formation and evolution. Accreting stellar-mass black holes in X-ray binaries are one of the best laboratories to study the accretion process and probe strong gravity—and most importantly, to measure the angular momentum, or spin, of black holes, and its role as a powering mechanism for relativistic astrophysical phenomena. Comprehensive characterization of the disk-corona system of accreting black holes, and their co-evolution, is fundamental to measurements of black hole spin. Here, we use simulated data to demonstrate how key unanswered questions in the study of accreting stellar-mass black holes will be addressed by the High Energy X-ray Probe (HEX-P). HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging and broad spectral coverage (0.2–80 keV) with a sensitivity superior to current facilities (including XMM-Newton and NuSTAR) to enable revolutionary new insights into a variety of important astrophysical problems. We illustrate the capability of HEX-P to: 1) measure the evolving structures of black hole binary accretion flows down to low (≲ 0.1%) Eddington-scaled luminosities via detailed X-ray reflection spectroscopy; 2) provide unprecedented spectral observations of the coronal plasma, probing its elusive geometry and energetics; 3) perform detailed broadband studies of stellar mass black holes in nearby galaxies, thus expanding the repertoire of sources we can use to study accretion physics and determine the fundamental nature of black holes; and 4) act as a complementary observatory to a range of future ground and space-based astronomical observatories, thus providing key spectral measurements of the multi-component emission from the inner accretion flows of black hole X-ray binaries.

Following the shift towards quantitative, corpus-based analysis in queer linguistics, I examine the usage of identity labels to explore the binary relationships and predicted normative effects in the case of the online community r/lgbt, a subreddit dedicated to minority identity labels and discussion. I analyze the distribution of the most frequent identity labels of the subreddit in a 2-year period with distributional semantic models, vector-based matrices that capture word distributions as numeric representations, showing evidence for various binaries that co-construct each other within the corpus. Additionally, I utilize concordances and collocations to examine the discourses surrounding gender and sexuality in the comments and submissions subcorpora, showing a more queer-aligned perspective in the former and a label-searching perspective in the latter. Finally, the results from these techniques demonstrate the overall complex relationships between the many types of labels currently in use and between the subreddit users and their feelings about adopting specific labels to describe their identities.

We investigate some properties of exotic spherical configurations made of dark matter and dark energy. For the former, we adopt a polytropic equation-of-state, while for the latter, we adopt the extended Chaplygin gas equation-of-state. Solving the Tolman–Oppenheimer–Volkoff equations, within the two-fluid formalism, we compute the factor of compactness, the mass-to-radius relationships, as well as the tidal Love numbers and dimensionless deformabilities. A comparison between single-fluid objects and two-fluid configurations is made as well. [ABSTRACT FROM AUTHOR]

This article's purpose is to analyse the political work of binaries used in both domestic and global migration governance responses with a particular focus on Zimbabwean "survival migration" at the Zimbabwe–South Africa border. This article finds that there is peculiar complementarity between South Africa's domestic migration governance framework and global migration governance frameworks aimed at a migration management approach. This article argues that this nice fit normalises the ostensibly clear distinction between migrants and refugees to deny protection to deserving asylum-seekers, which is productive in serving the political interests of the South African government. Without access to the appropriate papers and encountering a border refugee reception office that has developed de facto gatekeeping measures to prevent them from seeking asylum, as well as a United Nations High Commissioner for Refugees field office that perceives them as economic migrants, many Zimbabweans living in South Africa occupy a liminal area of categorisation and protection. Hence, the possibilities of the global migration governance providing legitimacy to exclusionary practices at the national level in South Africa are immense. This points to the need for serious engagement with "survival migration" as a category of mobility in analysis, policy, law as well as practice. [ABSTRACT FROM AUTHOR]

The results of photometric and spectral observations of T CrB obtained in a wide range of wavelengths in 2011–2023 are presented. We use the near-IR light curves to determine a new ephemeris for the times of light minima when the red giant is located between the observer and the hot component. The flux ratio H /H varied from to in 2020–2023, which may be due to a change in the flux ratio between the X-ray and optical ranges. It is shown that the value of H /H anticorrelates with the rate of accretion onto the hot component of the system. Based on high-speed follow-up observations obtained on June 8, 2023, we detected a variability of the He II line with a characteristic time-scale of min, the amplitude of variability in the -band was . Simulations of the near-IR light curves accounting for the ellipsoidal effect allowed us to obtain the parameters of the binary system: the Roche lobe filling factor of the cool component , the mass ratio , the orbital inclination . A comparison of the light curve obtained in 2005–2023 with the 1946 outburst template made it possible to predict the date of the upcoming outburst—January 2024. [ABSTRACT FROM AUTHOR]

We review recent works on the dynamics of circumbinary accretion, including time variability, angular momentum transfer between the disk and the binary, and the secular evolution of accreting binaries. These dynamics impact stellar binary formation/evolution, circumbinary planet formation/migration, and the evolution of (super)massive black hole binaries. We discuss the dynamics and evolution of inclined/warped circumbinary disks and connect with observations of protoplanetary disks. A special kind of circumbinary accretion involves binaries embedded in big disks, which may contribute to the mergers of stellar-mass black holes in AGN disks. Highlights include the following: Circumbinary accretion is highly variable, being modulated at Pb (the binary period) or ∼5Pb, depending on the binary eccentricity eb and mass ratio qb. The inner region of the circumbinary disk can develop coherent eccentric structure, which may modulate the accretion and affect the physical processes (e.g., planet migration) taking place in the disk. Over long timescales, circumbinary accretion steers binaries toward equal masses, and it does not always lead to binary orbital decay. The secular orbital evolution depends on the binary parameters (eb and qb) and on the thermodynamic properties of the accreting gas. A misaligned disk around a low-eccentricity binary tends to evolve toward coplanarity due to viscous dissipation. But when eb is significant, the disk can evolve toward "polar alignment," with the disk plane perpendicular to the binary plane. [ABSTRACT FROM AUTHOR]

We present optical and near-infrared (NIR) observations of the Type Icn supernova (SN Icn) 2022ann, the fifth member of its newly identified class of SNe. Its early optical spectra are dominated by narrow carbon and oxygen P-Cygni features with absorption velocities of ∼800 km s−1; slower than other SNe Icn and indicative of interaction with a dense, H/He-poor circumstellar medium (CSM) that is outflowing slower than typical Wolf–Rayet wind velocities of >1000 km s−1. We identify helium in NIR spectra 2 weeks after maximum and in optical spectra at 3 weeks, demonstrating that the CSM is not fully devoid of helium. Unlike other SNe Icn, the spectra of SN 2022ann never develop broad features from SN ejecta, including in the nebular phase. Compared to other SNe Icn, SN 2022ann has a low luminosity (o -band absolute magnitude of ∼−17.7), and evolves slowly. The bolometric light curve is well-modelled by 4.8 M⊙ of SN ejecta interacting with 1.3 M⊙ of CSM. We place an upper limit of 0.04 M⊙ of 56Ni synthesized in the explosion. The host galaxy is a dwarf galaxy with a stellar mass of 107.34 M⊙ (implied metallicity of log(Z/Z⊙) ≈ 0.10) and integrated star-formation rate of log (SFR) = −2.20 M⊙ yr−1; both lower than 97 per cent of galaxies observed to produce core-collapse supernovae, although consistent with star-forming galaxies on the galaxy Main Sequence. The low CSM velocity, nickel and ejecta masses, and likely low-metallicity environment disfavour a single Wolf–Rayet progenitor star. Instead, a binary companion is likely required to adequately strip the progenitor and produce a low-velocity outflow. [ABSTRACT FROM AUTHOR]

Drawing from the tensions within non-representational and human practice perspectives on affect, this paper continues the task of re-conceptualising academic-level resistance in the context of UK higher education. Such re-conceptualisation is underpinned by the belief that illustrating the breadth of resistant possibility within and between universities can assist in the development of action against the competitive and for-profit imperatives currently overwhelming this educational sphere. Indeed, while resistance research is increasingly interested in the (dis)connections between overt and “everyday” (Scott, 1985) forms of action (e.g. Contu, 2008; Zembylas, 2019), HE researchers have paid little attention to the latter. Consequently, academic-level resistance remains normatively portrayed as exceptional, novel and less influential than that it rejects. For the sake of contributing a counternarrative, this paper employs a diffractive methodology to examine the affective roles of emotion, meaning making practices and pre-personal factors. By speculating how academic-level resistance derives from not only consciously undertaken cost-benefit analyses but from the entanglement of material and non-material elements, this discussion emphasises the notion of “becoming” and so problematises reductive binaries of overt/covert, high-cost/low-cost, resister/complier. Irrespective of the resounding difficulties that accompany efforts to exploit the affective dimensions of resistance, this emphasis nevertheless situates possibility at the heart of UK higher education and the actions pushing against its neoliberal form.

Since 1877, the Seventh-day Adventist (SDA) Church from North America has established its presence in Southern Africa. As with missionization in other denominations, this introduced a variety of primarily Euro-American musical influences into African religious practices. Over the years, Adventist musicians have constantly negotiated a complex relationship to their African contexts, often yielding musical outcomes that cannot be reduced simply to an indigenous vs exogenous or 'African' vs 'Western' binary evaluation. This intersectional phenomenon is not thoroughly explored in the current scholarship on SDA music. This paper provides background and details on collaborations and exchanges in various repertoires since the 1980s. I argue that these embody intersectional ideas that emerge beyond geographical, cultural, and chronological boundaries. The study is developed from analyzing unstructured interviews and audio recordings to illustrate perpetually blurred boundaries in musical practices that have conventionally distinguished "African" vocal sound. [ABSTRACT FROM AUTHOR]

In this study, we use archival data from Hubble Space Telescope (HST), Chandra, XMM‐Newton, and Swift‐XRT, to probe the nature of 9 (X1‐X9) candidate ultraluminous X‐ray sources (ULXs) in NGC 1672. Our study focuses on using the precise source positions obtained via improved astrometry based on Chandra and HST observations to search for and identify optical counterparts for these ULXs. Unique optical counterparts are identified for X2 and X6; two potential counterparts were determined for X1, X5, and X7 within the respective error radii while no optical counterparts were found for the remaining four sources. Based on spectral energy distributions, X‐ray, and optical temporal analyses, some evidences about the nature of X1 and X2 were obtained. [ABSTRACT FROM AUTHOR]

We present the confirmation of SDSS J222551.65+001637.7AB as a closely separated, resolved, white dwarf–brown dwarf binary. We have obtained spectroscopy from GNIRS and seeing-limited Ks -band imaging from NIRI on Gemini North. The target is spatially resolved into its constituent components: a 10926 ± 246 K white dwarf, with log  g = 8.214 ± 0.168 and a mass of 0.66 |$^{+0.11}_{-0.06}$|  M⊙, and an L4 brown dwarf companion, which are separated by 0.9498 ± 0.0022 arcsec. We derive the fundamental properties of the companion from the Sonora–Bobcat evolutionary models, finding a mass of 25–53  M Jup and a radius of 0.101–0.128 R⊙ for the brown dwarf, at a confidence level of 1σ. We use wdwarfdate to determine the age of the binary as |$1.97^{+4.41}_{-0.76}$|  Gyr. A kinematic analysis shows that this binary is likely a member of the thick disc. The distance to the binary is 218 |$^{+14}_{-13}$|  pc, and hence the projected separation of the binary is 207 |$^{+13}_{-12}$|  au. Whilst the white dwarf progenitor was on the main sequence the binary separation would have been 69 ± 5 au. SDSS J222551.65+001637.7AB is the third closest spatially resolved white dwarf–brown dwarf binary after GD 165AB and PHL 5038AB. [ABSTRACT FROM AUTHOR]

We present a suite of high-resolution hydrodynamic simulations of binaries immersed in circumbinary accretion discs (CBDs). For the first time, we investigate the preferential accretion rate as a function of both eccentricity e b and mass ratio q b in a densely sampled parameter space, finding that when compared with circular binaries, (i) mass ratios grow more efficiently in binaries on moderately eccentric orbits (0.0 ≲ e b ≲ 0.4), and (ii) high eccentricities (e b ≳ 0.6) suppress mass ratio growth. We suggest that this non-monotonic preferential accretion behaviour may produce an observable shift in the mass ratio distributions of stellar binaries and massive black hole binaries. We further find that the response of a CBD can be divided into three regimes, depending on eccentricity and mass ratio: (i) CBDs around circular binaries always precess freely, whereas CBDs around eccentric binaries either (ii) undergo forced precession or (iii) remain locked at an angle with respect to the binary periapsis. Forced precession in eccentric binaries is associated with strong modulation of individual accretion rates on the precession time-scale, a potentially observable signature in accreting binaries with short orbital periods. We provide CBD locking angles and precession rates as a function of e b and q b for our simulation suite. [ABSTRACT FROM AUTHOR]

The origin of the spins of stellar-mass black holes is still controversial, and angular momentum transport inside massive stars is one of the main sources of uncertainty. Here, we apply hierarchical Bayesian inference to derive constraints on spin models from the 59 most confident binary black hole merger events in the third gravitational-wave transient catalogue (GWTC-3). We consider up to five parameters: chirp mass, mass ratio, redshift, effective spin, and precessing spin. For the model selection, we use a set of binary population synthesis simulations spanning drastically different assumptions for black hole spins and natal kicks. In particular, our spin models range from the maximal to minimal efficiency of angular momentum transport in stars. We find that if we include the precessing spin parameter into our analysis, models predicting only vanishingly small spins are in tension with GWTC-3 data. On the other hand, models in which most spins are vanishingly small but that also include a subpopulation of tidally spun-up black holes are a good match to the data. Our results show that the precessing spin parameter has a crucial impact on model selection.