Astronomische Nachrichten最新文献

{"title":"Quark/Hybrid Stars Within Perturbative QCD in View of the GW170817 Event","authors":"Fábio Köpp,&nbsp;Jorge Ernesto Horvath,&nbsp;Dimiter Hadjimichef,&nbsp;César A. Zen Vasconcellos","doi":"10.1002/asna.20240136","DOIUrl":"https://doi.org/10.1002/asna.20240136","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we examine the implications of perturbative Quantum Chromodynamics (pQCD) extrapolated from higher energies down to the neutron star range, as applied to hybrid stars. In describing the hybrid star, we represent the quark phase by pQCD, and the hadronic phase using the APR4 equation of state (EoS). The phase transition itself is modeled using the Maxwell construction. We hypothesize as a consequence of our work that the central compact object XMMU J173203.3, could be a quark star described by the pQCD EoS. Analysis of the mass-radius diagrams and the dimensionless tidal deformability are performed. The results obtained for the latter in the case of hybrid star models are consistent with observations from the GW170817 event; however, they do not meet the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>M</mi>\u0000 <mo>∼</mo>\u0000 <mn>2</mn>\u0000 <mspace></mspace>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mo>⊙</mo>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ Msim 2kern0.1em {M}_{odot } $$</annotation>\u0000 </semantics></math> constraint.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 B±-Meson Production in High Energy pp Collisions in the Color Dipole Transverse Momentum Representation","authors":"G. Sampaio dos Santos,&nbsp;G. Gil da Silveira,&nbsp;Magno V. T. Machado","doi":"10.1002/asna.20250007","DOIUrl":"https://doi.org/10.1002/asna.20250007","url":null,"abstract":"<div>\u0000 \u0000 <p>The color dipole formalism in the transverse momentum framework together with the unintegrated gluon distributions is considered to obtain the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>B</mi>\u0000 <mo>±</mo>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {B}^{pm } $$</annotation>\u0000 </semantics></math> differential cross sections in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>pp</mi>\u0000 </mrow>\u0000 <annotation>$$ pp $$</annotation>\u0000 </semantics></math> collisions. The theoretical predictions for the <i>B</i>^±-meson production assume the center-of-mass energy of the Large Hadron Collider and the rapidities available at the LHCb experiment. The results are compared with the corresponding measurements in terms of the meson transverse momentum.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144207019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Investigating Phase Transitions in Hybrid Stars Using the vMIT Bag Model and the QHD-II Model","authors":"Fábio Köpp,&nbsp;Jorge Ernesto Horvath,&nbsp;Dimiter Hadjimichef,&nbsp;César A. Zen Vasconcellos","doi":"10.1002/asna.20250006","DOIUrl":"https://doi.org/10.1002/asna.20250006","url":null,"abstract":"<div>\u0000 \u0000 <p>In this contribution, the global properties of hybrid compact stars resulting from a phase transition between hadronic matter and an interior composed of up, down, and strange quarks, based on a Maxwell construction, are studied. For the equation of state of the hadronic matter, we employ a covariant density functional theory within the framework of relativistic mean field theory, specifically the Quantum Hadrodynamics-II (QHD-II) model, with parameters determined using the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>NL</mi>\u0000 <msup>\u0000 <mn>3</mn>\u0000 <mo>*</mo>\u0000 </msup>\u0000 <mrow>\u0000 <mi>ω</mi>\u0000 <mi>ρ</mi>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation>$$ NL{3}^{ast}omega rho $$</annotation>\u0000 </semantics></math> parametrization. For the quark matter in the stellar core, we use the improved vMIT bag model, which incorporates repulsive interactions mediated by vector mesons, a crucial feature for describing stable and massive hybrid stellar configurations in agreement with recent observations of pulsars with masses above <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>2.0</mn>\u0000 <mspace></mspace>\u0000 <msub>\u0000 <mi>M</mi>\u0000 <mo>⊙</mo>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ 2.0kern0.1em {mathrm{M}}_{odot } $$</annotation>\u0000 </semantics></math>.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Modeling the Emission and Polarization Properties of Pulsating Ultraluminous X-Ray Sources","authors":"S. Conforti,&nbsp;L. Zampieri,&nbsp;R. Taverna,&nbsp;R. Turolla,&nbsp;N. Brice,&nbsp;F. Pintore,&nbsp;G. L. Israel","doi":"10.1002/asna.20240129","DOIUrl":"https://doi.org/10.1002/asna.20240129","url":null,"abstract":"<p>Pulsating Ultraluminous X-ray Sources (PULXs) are a class of extragalactic sources with high X-ray luminosity, in excess of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mn>10</mn>\u0000 <mn>39</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {10}^{39} $$</annotation>\u0000 </semantics></math> erg <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ {mathrm{s}}^{-1} $$</annotation>\u0000 </semantics></math>, and showing pulsations that associate them with neutron stars accreting at a super-Eddington rate. A simplified model is presented, which describes the thermal emission from an accreting, highly magnetized neutron star and includes the contributions from an accretion disk and an accretion envelope surrounding the star magnetosphere. Through numerical calculations, we determine the flux, pulsed fractions, polarization degree, and polarization angle considering various viewing geometries. The model is confronted with the <i>XMM-Newton</i> spectra of M51 ULX-7, and the best fitting viewing geometries are estimated. A measurement of the polarization observables, which will be available with future facilities, along with spectroscopic data obtained with <i>XMM-Newton</i>, will provide considerable additional information on these sources.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240129","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superhabitable Planets Around Mid-Type K Dwarf Stars Enhance Simulated JWST Observability and Surface Habitability","authors":"Iva Vilović,&nbsp;Jayesh Goyal,&nbsp;René Heller,&nbsp;Fanny Marie von Schauenburg","doi":"10.1002/asna.20240081","DOIUrl":"https://doi.org/10.1002/asna.20240081","url":null,"abstract":"<p>In our search for life beyond the Solar System, certain planetary bodies may be more conducive to life than Earth. However, the observability of these “superhabitable” (SH) planets in the habitable zones around K dwarf stars has not been fully modeled. This study addresses this gap by modeling the atmospheres of SH exoplanets. We employed the 1D model <i>Atmos</i> to define the SH parameter space, <i>POSEIDON</i> to calculate synthetic transmission spectra, and <i>PandExo</i> to simulate JWST observations. Our results indicate that planets orbiting mid-type K dwarfs, receiving 80% of Earth's solar flux, are optimal for life. These planets sustain temperate surfaces with moderate CO₂ levels, unlike those receiving 60% flux, where necessarily higher CO₂ levels could hinder biosphere development. Moreover, they are easier to observe, requiring significantly fewer transits for biosignature detection compared with Earth-like planets around Sun-like stars. For instance, detecting biosignature pairs like oxygen and methane from 30 pc would require 150 transits (43 years) for a SH planet, versus over 1700 transits (~1700 years) for Earth-like planets. While such observation times lie outside of JWST mission timescales, our study underscores the necessity of next-generation telescopes and provides valuable targets for future observations with, for example, the ELT.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uncertainties in Ground-Based Visual Double Star Measures","authors":"Roderick R. Letchford,&nbsp;Graeme L. White","doi":"10.1002/asna.20240086","DOIUrl":"https://doi.org/10.1002/asna.20240086","url":null,"abstract":"<p>Stellar masses are found from the orbital elements of binary systems which are, in turn, computed from weighted astrometric measures. Astrometric measures of double stars (their position angle and separation) rarely include uncertainties, and published binary star orbits rarely include the weighting systems used in the determination of the orbital elements. Here we propose a simple method for estimating uncertainties of ground-based measures of visual double stars based on precision space-based astrometry of optical (not binary) double stars, which can be used as unbiased weights for all double star measures. The precision of ground-based measures is examined as (i) a function of the date of observation, (ii) the telescope aperture, and (iii) the instrumentation (technique) used at the telescope. We also note in the Appendix, 19 pairs that are incorrectly described in Lin2 and six rectilinear pairs that may display curved motion.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Where in the Milky Way Do Exoplanets Preferentially Form?","authors":"Joana Teixeira,&nbsp;Vardan Adibekyan,&nbsp;Diego Bossini","doi":"10.1002/asna.20240076","DOIUrl":"https://doi.org/10.1002/asna.20240076","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;Exoplanets are detected around stars of different ages and birthplaces within the Galaxy. The aim of this work is to infer the Galactic birth radii (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mtext&gt;birth&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {r}_{mathrm{birth}} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) of stars and, consequently, their planets, with the ultimate goal of studying the Galactic aspects of exoplanet formation. We used photometric, spectroscopic, and astrometric data to estimate the stellar ages of two samples of stars hosting planets and, for comparison, a sample of stars without detected planets. The &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mtext&gt;birth&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {r}_{mathrm{birth}} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; of exoplanets were inferred by projecting stars back to their birth positions based on their estimated age and metallicity [Fe/H]. We find that stars hosting planets have higher [Fe/H], are younger, and have smaller &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mtext&gt;birth&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {r}_{mathrm{birth}} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; compared to stars without detected planets. In particular, stars hosting high-mass planets show higher [Fe/H], are younger, and have smaller &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;r&lt;/mi&gt;\u0000 &lt;mtext&gt;birth&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt;$$ {r}_{mathrm{birth}} $$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; than stars hosting low-mass planets. We show that the formation efficiency of planets, calculated as the relative frequency of planetary systems, decreases with the galactocentric distance, which relationship is stronger for high-mass planets than for low-mass planets. Additionally, we find that (i) the formation efficiency of high-mass planets increases with time and encompasses a larger galactocentric distance over time; (ii) the formation efficiency of low-mass planets shows a slight increase between the ages of 4 and 8 Gyr and also encompasses a larger galactocentric distance over time; and (iii) stars without detected planets appear to form at larger galactocentric distances over time. We conclude that the formation of exoplanets throughout the Galaxy follows the Galactic chemical evolution, for which our results are in agreement with the observed negative interstellar medium (ISM)","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 2","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Exploring Absolute Retract in Regular Hayward Black Holes and Their Implications for Astrophysics","authors":"Mohammad Abu-Saleem,&nbsp;Ali Taani","doi":"10.1002/asna.20240148","DOIUrl":"https://doi.org/10.1002/asna.20240148","url":null,"abstract":"<div>\u0000 \u0000 <p>In this article, we study and describe the topology of the spherically symmetric and regular (with no singularity in its event horizon) black hole, which is called Hayward black hole. We use the symmetric metric for this object, associated with the Euler-Lagrangian equation, to derive various types of geodesic equations and components of a subspace geodesic. Under certain conditions, this approach allows us to deduce three types of absolute retractions representing the particle's motion along different axes within a 3-D subspace. These retractions could potentially describe the region of the event horizon of Hayward black holes. We show that the radial geodesics describe motion directly toward the black hole's center, while tangential geodesics illustrate paths without angular displacement. Spacetime curvature near the event horizon emphasizes the intense gravitational effects and distortions caused by the black hole's mass. Particle motion in subspace <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mspace></mspace>\u0000 <msub>\u0000 <mi>ℋ</mi>\u0000 <mn>3</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ kern0.5em {mathrm{mathscr{H}}}_3 $$</annotation>\u0000 </semantics></math> represents constrained tangential dynamics, providing insights into localized spacetime. In addition, the study of the Hayward black hole (topology and geometry) is valuable for our understanding of general relativity, exploring the quantum field of gravity implications, and contribute to the fields of mathematical physics and astrophysics.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Unveiling the Magnetized Nature of X-Ray Binaries: Cyclotron Line Insights Title","authors":"Mohammad Tayem,&nbsp;Mohammad Abu-Saleem,&nbsp;Ali Taani","doi":"10.1002/asna.20240147","DOIUrl":"https://doi.org/10.1002/asna.20240147","url":null,"abstract":"<div>\u0000 \u0000 <p>Studying the variations of measured cyclotron lines plays a crucial role in gaining insights into the physical processes of accretion in magnetized neutron stars. Our research focuses on the formation and distribution of magnetic fields in various high-mass x-ray binaries (HMXBs). Comparing these sources reveals valuable information about their origin and evolutionary history. It is worth noting that the presence of varying cyclotron lines can be attributed to the influence of accretion dynamics, which provides valuable information about the characteristics of the magnetic field. In addition, by visualizing data, we employ the Kernel Density Estimation method, to provide a robust framework for understanding the distribution of magnetic fields. We observed clear patterns of clustering in the energy range of (10–35) keV, which corresponds to magnetic fields of around <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mrow>\u0000 <mn>2</mn>\u0000 <mtext>–</mtext>\u0000 <mn>4</mn>\u0000 </mrow>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <mo>×</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>12</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation>$$ left(2hbox{--} 4right)times 1{0}^{12} $$</annotation>\u0000 </semantics></math> G. This clustering indicates a shared magnetic field characteristics across these systems, suggesting a possible common origin or similar environmental and accretion condi tions. Finally, our research investigates the behavior of cyclotron lines in HMXBs, illuminating the accretion process and magnetic field properties to better understand their role as indicators of dynamical evolution.</p>\u0000 </div>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 3-4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Meaning of Quasi-Simultaneous X-Rays and Gamma-Ray Observations of RS Oph in Outburst","authors":"Marina Orio,&nbsp;Ke Fang,&nbsp;Jay Gallagher,&nbsp;Gerardo Juan M. Luna,&nbsp;Joanna Mikolajewska","doi":"10.1002/asna.20240140","DOIUrl":"https://doi.org/10.1002/asna.20240140","url":null,"abstract":"<p>Shocks in novae outbursts are ubiquitous, but in symbiotic novae, they are particularly powerful, probably because of the surrounding red giant wind. The recurrent nova RS Oph is the best example of this phenomenon. The presence of shocked plasma in outburst was inferred from optical spectra, and it was confirmed by X-ray observations since 1985. Since 2010, the gamma-ray observatory Fermi has proven that novae in general are the site of particle acceleration, producing copious gamma-ray flux in the few-GeV range. In the last outburst of the symbiotic RS Oph in 2021, gamma-rays were not only detected with Fermi in the GeV range but also detected in the TeV range of the Cherenkov telescopes, for about 3 weeks. Diesing et al. in 2023 showed that there must have been at least two distinct episodes of shocks, likely of hadronic nature, both generating particle acceleration. We present new NuSTAR data and re-discuss XMM-Newton high-resolution grating spectra and NICER data that we recently published. We concluded that the primary shock causing the particle acceleration observed in the range of TeV gamma-rays with the Cherenkov telescopes was the same phenomenon observed and studied with the x-ray observatories. However, the shocked plasma from which the particles were accelerated causing the gamma-ray flux observed after 1 day with Fermi was—at least initially—unobservable. We suggest that this first episode of shock occurred when the nova ejecta collided with a dense outflow close to the atmosphere of the red giant, with such a high absorbing column that x-rays were absorbed.</p>","PeriodicalId":55442,"journal":{"name":"Astronomische Nachrichten","volume":"346 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/asna.20240140","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143114534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}