Astronomy & Astrophysics最新文献

{"title":"State-to-state rotational rate coefficients for the OCS+H2 collision at low temperatures","authors":"Otoniel Denis-Apizar, Ignacio A. Murúa-Molina, Cristian Guerra, Rodrigo Urzúa-Leiva","doi":"10.1051/0004-6361/202555275","DOIUrl":"https://doi.org/10.1051/0004-6361/202555275","url":null,"abstract":"<i>Context.<i/> The physicochemical conditions of interstellar regions with low densities, (e.g., typical molecular clouds), should be analyzed using non-LTE models. In such models, the collisional rate coefficients of the observed molecules with H<sub>2<sub/>, He, and H are critical inputs. In the case of OCS, the only set of rate coefficients available for the collision with H<sub>2<sub/> was computed in the seventies, using a potential energy surface (PES) based on an electron gas model for the collision with He. Furthermore, in a recent study on OCS+He, a mass-scaled approximation for the rates was considered, and different propensity rules were found.<i>Aims.<i/> The main goal of this study is to compute a new set of rotational de-excitation rate coefficients of OCS in collision with H<sub>2<sub/> at low temperatures.<i>Methods.<i/> An averaged PES over the orientation of H<sub>2<sub/> is developed from a large grid of ab initio energies computed at the CCSD(T)/aug-cc-pVQZ level of theory. This surface is employed in close-coupling calculations for studying the collision of OCS with para-H<sub>2<sub/>(<i>j<i/> = 0). Furthermore, an available 4D PES was also used in close-coupling calculations to confirm the results of our first approximation.<i>Results.<i/> The agreement between the cross sections for the OCS+para-H<sub>2<sub/> computed using the reduced and 4D PES was very good. The state-to-state rotational de-excitation rate coefficients for the lowest 30 rotational states of OCS by para-H<sub>2<sub/> are computed from these data. However, the rate coefficients show different behavior with published data; particularly, a different propensity rule, Δ<i>j<i/> = 1, is found. Furthermore, similarities between the rates with para- and ortho-H<sub>2<sub/> are found. Finally, the astrophysical implications of the new rate coefficients are explored from non-LTE radiative transfer calculations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"3 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Peekaboo galaxy: New SALT spectroscopy and implications of archive HST data","authors":"A. Y. Kniazev, S. A. Pustilnik","doi":"10.1051/0004-6361/202554911","DOIUrl":"https://doi.org/10.1051/0004-6361/202554911","url":null,"abstract":"<i>Context.<i/> The dwarf galaxy Peekaboo (HIPASSJ1131–31) was recently identified as a local volume (LV) gas-rich and extremely metal-poor (XMP) dIrr. Its gas metallicity is <i>Z<i/> ∼ Z<sub>⊙<sub/>/50, with a ±1<i>σ<i/> uncertainty range of [Z<sub>⊙<sub/>/72–Z<sub>⊙<sub/>/35]). Its ‘tip of the red-giant branch’ distance is 6.8 ± 0.7 Mpc. The Hubble Space Telescope (HST) data for its individual stars revealed that its older red-giant-branch stars comprise a smaller part of the galaxy, while the majority of visible stars have ages of less than one to a few gigayears. Thus, the Peekaboo dwarf can be considered as the nearest record-low <i>Z<i/> dwarf. As such, the galaxy deserves a deeper multi-method study that examines the properties of its young massive stars and the fainter older population as well as its ionised gas and the dominant baryonic component of HI gas.<i>Aims.<i/> We aim to obtain the higher S-to-N SALT optical spectra of two H II regions in Peekaboo in order to improve the accuracy of its gas O/H and to determine abundances of Ne, S, N, and Ar. With archive HST images, we aim to identify the hot massive stars, including exciting the two H II regions (i.e. east and west), and the XMP supergiants as important targets for follow-up studies of their evolution with upcoming extremely large telescopes.<i>Methods.<i/> We used the direct (T<sub>e<sub/>) method for the east H II region in which a [O III]<i>λ<i/>4363 Å line is well detected in order to estimate its parameter 12 + log(O/H). In the west H II region, the line [OIII]<i>λ<i/>4363 Å is not detected, so we estimated its O/H via the empirical ‘strong-line’ method of Izotov et al. (2019, A&A, 523, A40). The resulting value of O/H is very close to that in the east H II region.<i>Results.<i/> The new spectroscopy of the Peekaboo dwarf allowed us to substantially improve the accuracy of its direct O/H estimate, and we obtained 12 + log(O/H) = 6.99 ± 0.06 dex. The new data reveal that emission lines in the east region consist of two components with a velocity difference of ∼65 km s<sup>−1<sup/>. The fainter approaching component could be related to a fast-moving WR star thrown from a cluster or a binary system. Using the HST <i>V<i/> magnitudes and colour <i>V<i/> − <i>I<i/>, we identified tentative O-type and very hot candidate WO stars, which are likely the ionising stars of the studied H II regions.<i>Conclusions.<i/> With the new optical spectra, the Peekaboo galaxy is confirmed as the lowest-metallicity dwarf in the LV and as a valuable object for in-depth multi-method studies. We separate its most luminous stars for follow-up ground-based brightness monitoring and spectroscopy.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"10 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UGC 10043 in depth: Dissecting the polar bulge and subtle low surface brightness features","authors":"S. K. H. Bahr, A. V. Mosenkov","doi":"10.1051/0004-6361/202554995","DOIUrl":"https://doi.org/10.1051/0004-6361/202554995","url":null,"abstract":"Galaxies with polar structures (of which polar-ring galaxies (PRGs) are a prominent subclass) contain components that are kinematically decoupled and highly inclined relative to the major axis of the host galaxy. Modern deep optical surveys provide a powerful means of detecting low surface brightness (LSB) features around galaxies, which offers critical insights into the formation and evolution of galaxies with polar structures. UGC 10043 is an edge-on galaxy that is notable for its prominent bulge, which extends orthogonally to the disk plane. In addition, the galaxy displays a well-defined integral-shaped disk warp and multiple dust features crossing the bulge along the minor galaxy axis. We present new deep optical photometry of UGC 10043 down to <i>μ<i/><sub><i>g<i/><sub/> = 29.5 mag arcsec<sup>−2<sup/> and perform a detailed analysis of its LSB and polar structures. The observations reveal a stellar stream aligned along the polar axis, alongside other signatures of tidal interaction, including a flat, tilted LSB envelope that extends toward the neighboring galaxy MCG +04-37-035, with which UGC 10043 is connected by an HI bridge. Our results suggest that the polar component of UGC 10043 comprises an older, triaxial polar bulge and a younger, forming polar structure that likely originates from the ongoing disruption of a dwarf satellite galaxy. It also simultaneously participates in active interaction with MCG +04-37-035.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The incidence of magnetic cataclysmic variables can be explained by the late appearance of white dwarf magnetic fields","authors":"Matthias R. Schreiber, Diogo Belloni","doi":"10.1051/0004-6361/202554828","DOIUrl":"https://doi.org/10.1051/0004-6361/202554828","url":null,"abstract":"<i>Context.<i/> Assuming that white dwarf (WD) magnetic fields are generated by a crystallization- and rotation-driven dynamo, the impact of the late appearance of WD magnetic fields in cataclysmic variables (CVs) has been shown to potentially solve several long-standing problems of CV evolution. However, recent theoretical works show that the dynamo idea might not be viable and that the late appearance of WD magnetic fields might be an age effect rather than related to the cooling of the core of the WD.<i>Aims.<i/> We investigated the impact of the late appearance of WD magnetic fields on CV evolution assuming that the fields appear at fixed WD ages.<i>Methods.<i/> We performed CV population synthesis with the BSE code to determine the fractions of CVs that become magnetic at different evolutionary stages. These simulations were complemented with MESA tracks that take into account the transfer of spin angular momentum to the orbit which can cause a detached phase.<i>Results.<i/> We find that the observed fraction of magnetic CVs as a function of orbital period is well reproduced by our simulations, and that in many CVs the WD should become magnetic close to the period minimum. The detached phase generated by the transfer of spin angular momentum is longest for period bouncers.<i>Conclusions.<i/> Interpreting the late appearance of strong WD magnetic fields as a simple age effect naturally explains the relative numbers of magnetic CVs in observed samples. As many period bouncers might detach for several gigayears, the late appearance of WD magnetic fields at a fixed age and independent of the core temperature of the WD can significantly reduce the predicted number of accreting period bouncers.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"33 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From small dust to micron-sized aggregates: The influence of structure and composition on the dust optical properties","authors":"M.-A. Carpine, N. Ysard, A. Maury, A. Jones","doi":"10.1051/0004-6361/202554575","DOIUrl":"https://doi.org/10.1051/0004-6361/202554575","url":null,"abstract":"<i>Context.<i/> Models of astrophysical dust are key to understanding several physical processes, from the role of dust grains as cooling agents in the interstellar medium (ISM) to their evolution in dense circumstellar discs, explaining the occurrence of planetary systems around many stars. Currently, most models aim to provide optical properties for dust grains in the diffuse ISM, and many do not account properly for complexity in terms of composition and structure when dust is expected to evolve in dense astrophysical environments.<i>Aims.<i/> Our purpose is to investigate, with a pilot sample of micron-size dust grains, the influence of hypotheses made about the dust structure, porosity, and composition when computing the optical properties of grown dust grains. We aim to produce a groundwork for building comprehensive yet realistic optical properties that accurately represent dust grains as they are expected to evolve in the dense clouds, cores, and discs. We are especially interested in exploring these effects on the resulting optical properties in the infrared and millimetre domains, where observations of these objects are widely used to constrain the dust properties.<i>Methods.<i/> Starting from the small dust grains developed in the THEMIS 2.0 model, we used the discrete dipole approximation to compute the optical properties of 1 μm grains, varying the hypotheses made about their composition and structure. We looked at the dust scattering, emission, and extinction to isolate potential simplifications and unavoidable differences between grain structures.<i>Results.<i/> We note significant differences in the optical properties depending on the dust structure and composition. Both the dust structure and porosity influence the dust properties in infrared and millimetre ranges, demonstrating that dust aggregates cannot be correctly approximated by compact or porous spheres. In particular, we show that the dust emissivity index in the millimetre can vary with fixed grain size.<i>Conclusions.<i/> Our work sheds light on the importance of taking the dust structure and porosity into account when interpreting observations in astrophysical environments where dust grains may have evolved significantly. For example, measuring the dust sizes using the emissivity index from millimetre observations of the dust thermal emission is a good but degenerate tool, as we observe differences of up to 25% in the dust emissivity index with compact or aggregate grains, varying in composition and structure. Efforts in carrying out physical models of grain growth, for instance, are required to establish realistic constraints on the structure of grown dust grains, and will be used in the future to build realistic dust models for the dense ISM.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"592 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of propenethial (CH2CHCHS) in TMC-1","authors":"C. Cabezas, K. Vávra, G. Molpeceres, L. Kolesniková, M. Agúndez, G. Vylitová, N. Marcelino, L. Hrubčík, R. Fuentetaja, T. Uhlíková, B. Tercero, J. Koucký, G. Esplugues, P. Kania, P. de Vicente, Š. Urban, J. Cernicharo","doi":"10.1051/0004-6361/202554670","DOIUrl":"https://doi.org/10.1051/0004-6361/202554670","url":null,"abstract":"We present the detection of propenethial (CH<sub>2<sub/>CHCHS), the sulphur analogue of interstellar acrolein (CH<sub>2<sub/>CHCHO), towards TMC-1. The detection of this new sulphur molecule in TMC-1 is based on the data derived from rotational spectroscopy laboratory experiments, including new data in the millimetre wave domain, which are also presented in this work. Propenethial was observed in the cold dark cloud TMC-1 using data from the ongoing QUIJOTE line survey, which is being carried out with the Yebes 40m telescope. A total of nine rotational transitions with <i>J<i/> = 6 up to 9 and <i>K<i/><sub><i>a<i/><sub/> = 0 and 1 were detected in the 31.0–50.4 GHz range. We derive a total column density for propenethial of (4.4 ± 0.4) × 10<sup>10<sup/> cm<sup>−2<sup/>, which is 2, 6.8, and 27 times smaller than those for CH<sub>3<sub/>CHS, HCCHS, and NCCHS, which are the other thioaldehyde derivatives detected in TMC-1. The abundance ratio found in TMC-1 between the aldehyde counterpart, acrolein, and propenethial is 4.7, which is also different from those found for other pairs of aldehydes-thioaldehydes in this source. Our investigation of possible chemical formation pathways suggests that CH<sub>2<sub/>CHCHS likely results from a combination of gas- and surface-phase reactions.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"65 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ionisation balance and equation of state of hot, dense carbon plasmas at pressures up to a few 100 Gbar","authors":"Jiaolong Zeng, Yihua Huang, Aihua Deng, Cheng Gao, Yong Hou, Jianmin Yuan","doi":"10.1051/0004-6361/202554609","DOIUrl":"https://doi.org/10.1051/0004-6361/202554609","url":null,"abstract":"Accurately determining the ionisation balance and the equation of state (EOS) of dense plasmas is crucial for investigating the structure, evolution, and interior of stars, as well as other high-density astrophysical objects. However, it is still challenging for current experiments and theories to achieve this objective for dense plasmas at pressures up to a few 100 Gbar. Here, we modify the chemical picture of the Saha equation of plasmas and extend it into a regime up to a density of a few hundred g cm<sup>−3<sup/> based on the minimisation of the free energy of the system. The non-ideal characteristics (NIC) of the free energy, particularly the part contributed by Coulomb interactions between electrons and ions, as well as among the electrons and ions themselves, are properly accounted for by employing a local-density, temperature-dependent ion-sphere model. In such a way, the NIC effects on the ionisation potential depression, the internal partition functions of the ions, and the partition functions of the free electrons are properly considered in the modified Saha equation. Hence, the ionisation balance and EOS are self-consistently determined in this theoretical formalism. We demonstrate the capability of this modified Saha equation for solving hot, dense carbon plasmas, and find that the accurate prediction of the critical density above which the K-shell electrons become delocalised by pressure is crucial for accurately obtaining the charge state distribution and the EOS. Comparisons are made for the average degree of ionisation and EOS of carbon plasmas with available data reported in the literature. Our predicted EOS gives a result in reasonable agreement with other theoretical results below the critical density of pressure-driven K-shell delocalisation. Nevertheless, above this critical density, our prediction is systematically higher by ~25% compared to most other theories. At mass densities around 5 g cm<sup>−3<sup/>, our predicted opacity of dense hydrocarbon plasmas agrees with a recent experiment studying the EOS along the principal shock Hugoniot, which can be considered a validation of our theory at this density regime.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The p-Laplacian as a framework for generalizing Newtonian gravity and Milgromian gravitation","authors":"D. Scherer, J. Pflamm-Altenburg, P. Kroupa, E. Gjergo","doi":"10.1051/0004-6361/202554793","DOIUrl":"https://doi.org/10.1051/0004-6361/202554793","url":null,"abstract":"<i>Context.<i/> The radial acceleration relation (RAR) follows from Milgromian gravitation (MoND) and velocity dispersion data of many dwarf spheroidal galaxies (dSphs) and galaxy clusters have been reported to be in tension with it.<i>Aims.<i/> We consider the generalized Poisson equation (GPE), expressed in terms of the p-Laplacian, which has been applied in electrodynamics, and investigate whether it can address these tensions.<i>Methods.<i/> From the GPE we derive a generalized RAR characterized by the <i>p<i/> parameter from the p-Laplacian and a velocity dispersion formula for a Plummer model. We apply these models to Milky Way and Andromeda dSphs and HIFLUGS galaxy clusters and derive a <i>p<i/> parameter for each dSph and galaxy cluster. We explore a relation of <i>p<i/> to the mass density of the bound system, and alternatively a relation of <i>p<i/> to the external field predicted from Newtonian gravity<i>Results.<i/> This ansatz allows the deviations of dSphs and galaxy clusters from the RAR without the need of introducing dark matter. Data points deviate from the Milgromian case, <i>p<i/> = 3, with up to 5<i>σ<i/>-confidence. Also, we find the model predicts velocity dispersions, each of which lies in the 1<i>σ<i/>-range of their corresponding data point allowing the velocity dispersion to be predicted for early-type dwarf satellite galaxies from their baryonic density. The functional relation between the mass density of the bound system and <i>p<i/> suggests <i>p<i/> to increase with decreasing density. We find for the critical cosmological density <i>p<i/>(<i>ρ<i/><sub>crit<sub/>) = 12.27±0.39. This implies significantly different behaviour of gravitation on cosmological scales. Alternatively, the functional relation between <i>p<i/> and the external Newtonian gravitational field suggests <i>p<i/> to decrease with increasing field strength.<i>Conclusions.<i/> The GPE fits the RAR data of dSphs and galaxy clusters, reproduces the velocity dispersions of the dSphs, gives a prediction for the velocity dispersion of galaxy clusters from their baryonic density and may explain the non-linear behaviour of galaxies in regions beyond the Newtonian regime.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"230 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New constraints on the values of the fundamental constants at a look-back time of 7.3 Gyr","authors":"Renzhi Su, Stephen J. Curran, Françoise Combes, Neeraj Gupta, Sebastien Muller, Di Li, Minfeng Gu","doi":"10.1051/0004-6361/202453407","DOIUrl":"https://doi.org/10.1051/0004-6361/202453407","url":null,"abstract":"The study of redshifted spectral lines can provide a measure of the fundamental constants over large look-back times. Current grand unified theories predict an evolution in these constants and astronomical observations offer the only experimental measure of the values of the constants over large timescales. Of particular interest are the dimensionless constants: the fine structure constant (<i>α<i/>), the proton-electron mass ratio (<i>μ<i/>), and the proton g-factor (<i>g<i/><sub><i>p<i/><sub/>), since these do not require a “standard meterstick”. Here we present a re-analysis of the 18 cm hydroxyl (OH) lines at <i>z<i/> = 0.89, which were recently detected with the MeerKAT telescope, toward the radio source PKS 1830-211. Utilizing the previous constraint of Δ<i>μ<i/>/<i>μ<i/>=(−1.8±1.2)×10<sup>−7<sup/>, we obtain , Δ<i>α<i/>/<i>α<i/>≲2.3×10<sup>−3<sup/>, and Δ<i>g<i/><sub><i>p<i/><sub/>/<i>g<i/><sub><i>p<i/><sub/>≲7.9×10<sup>−3<sup/>. These new constraints are consistent with no evolution over a look-back time of 7.3 Gyr and provide another valuable data point in the putative evolution of the constants.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"70 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Particle acceleration and multi-messenger radiation from ultra-luminous X-ray sources","authors":"Enrico Peretti, Maria Petropoulou, Georgios Vasilopoulos, Stefano Gabici","doi":"10.1051/0004-6361/202452987","DOIUrl":"https://doi.org/10.1051/0004-6361/202452987","url":null,"abstract":"Super-Eddington accretion onto stellar-mass compact objects powers fast outflows in ultra-luminous X-ray sources (ULXs). Such outflows, which can reach mildly relativistic velocities, are often observed forming bubble structures. Wind bubbles are expected to develop strong wind termination shocks, which are sites of great interest for diffusive shock acceleration. We developed a model of diffusive shock acceleration in the wind bubbles powered by ULXs. We find that the maximum energy in these objects can easily reach the PeV range, promoting winds from ULXs as a new class of PeVatrons. We specialized our model in the context of the Galactic source SS 433 and show that high-energy protons in the bubble might explain the highest energy photons (>100 TeV) and their morphology recently observed by LHAASO. In this paper, we discuss the detectability of such a source in neutrinos, and we analyze the possible radio counterpart of ULXs focusing on the case of W50, the nebula surrounding SS 433. Finally, we discuss the possible contribution of Galactic ULXs to the cosmic-ray flux at the knee, concluding that their role could be significant only if one of these sources, currently undetected, were sufficiently close.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"25 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}