Astronomy & Astrophysics最新文献

{"title":"Theoretical RR Lyrae instability strip from MESA-RSP pulsation models and updated BaSTI evolutionary tracks","authors":"M. Deka,M. Marconi,R. Molinaro,A. Bhardwaj,S. Cassisi,E. Luongo,G. De Somma,I. Musella,V. Ripepi","doi":"10.1051/0004-6361/202662656","DOIUrl":"https://doi.org/10.1051/0004-6361/202662656","url":null,"abstract":"RR Lyraes (RRLs) are important tracers of old stellar populations and crucial distance indicators. To complement large variability surveys such as and Rubin-LSST, the topology of the RRL instability strip (IS) and their period-luminosity-metallicity (PLZ) and period-Wesenheit-metallicity (PWZ) relations must be updated using state-of-the-art stellar evolution and pulsation models. Gaia We employed the updated set of BaSTI horizontal branch (HB) evolutionary models, with finer sampling in effective temperature and metallicity, and computed the corresponding pulsation models using the module. We aimed to quantify how the predicted IS boundaries and PLZ and PWZ relations depend on the adopted convection prescription and mixing-length parameter. We computed a grid of linear nonadiabatic radial pulsation models with łeq +0.06 dex. Seven convection configurations were explored including a recently empirically calibrated prescription for RRLs. Analytical IS boundaries were derived for RRab and RRc pulsators and transformed into several photometric systems (Gaia, OGLE, 2MASS, and LSST) and the Kiel diagram. covering -2.2 łeq Fe/H The updated evolutionary models do not substantially change the pulsation predictions: RRab IS edges agree well with previous results, while the RRc red edge is slightly redder. The width of the IS decreases systematically with increasing α_̊m MLT, and RRc is relatively more sensitive to the convection prescription than RRab. Testing both linear and quadratic edge fits, RRc IS favors a quadratic luminosity term in most cases, indicating intrinsic curvature of the first-overtone IS. The observed sample lies well within our predicted IS edges when compared in the $(J-K ̊m s )_0$ versus M_ K_ ̊m s color–magnitude diagram. The PLZ and PWZ relations are also in good agreement with previous empirical and theoretical calibrations across the near-infrared bands; however, the convection prescription giving the closest match is wavelength-dependent. The theoretical PWZ relation shows a modest offset from the empirical Milky Way field relation, which diminishes significantly when compared at matching cluster metallicities. Gaia The predicted IS boundaries, PLZ and PWZ relations exhibit a coupled dependence on pulsation mode, metallicity, and convective treatment, with no single prescription performing uniformly best across all observational planes. The theoretical relations presented here are directly applicable to large RRL datasets from ongoing and forthcoming surveys, including and Rubin-LSST. Gaia","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209112","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":"Something green beneath the surface: The dynamical nature of fossil structures in IllustrisTNG-100","authors":"Mary Verdugo-Santos,Facundo A. Gómez,Diego Pallero,Franklin Aldás,Cristian A. Vega-Martínez","doi":"10.1051/0004-6361/202661412","DOIUrl":"https://doi.org/10.1051/0004-6361/202661412","url":null,"abstract":"Fossil structures (FSs) have traditionally been considered dynamically relaxed end products of group evolution, characterized by a large magnitude gap (Δ m_ 1,2 ≥ 2). However, recent observations and simulations suggested that this picture is incomplete, motivating a reassessment of their nature using cosmological simulations. We investigated the dynamical relaxation state of FSs, the differences in their galaxy populations relative to non-fossil systems (non-FSs), and the assembly history of the two populations. We focused on the system dynamics and the evolution of galaxies within them. Using IllustrisTNG-100, a state-of-the-art cosmological simulation, we selected 182 structures (M_ 200 > 10^ 13 ,M_⊙) at z = 0, classified them as FSs or non-FSs based on Δ 1,2 in the r band. We tracked the Δ m_ 1,2 evolution over 9,Gyr and analyzed (1) the emergence of Δ m_ 1,2 and its relation to the last significant accretion event onto the system, (2) the fraction of quenched galaxies (specific star formation rate $< 10^ -11 $,yr -1 ), (3) the distribution of galaxies in color--stellar mass space, and (4) the centroid shift in the gas--Brightest Structure Galaxy (BSG) as a dynamical proxy. The magnitude gap in FSs is primarily driven by the absence of massive recent accretion: FSs exhibit significantly lower BSG-to-satellite stellar mass ratios (μ^ FS _⋆=0.17 vs. μ^ NFS _⋆=0.39) for the most massive satellite accreted within the last 6,Gyr. FSs also host a more prominent red sequence and marginally higher quenched fractions than non-FSs. Furthermore, non-FSs show more prominent green-valley populations, which are associated with the secondary massive galaxy behind the small-magnitude gap. When we compared the gas--BSG centroid offsets, we found that both populations occupy an intermediate dynamical state ̊m BSG-CM ≈ 0.14--0.16 R/R_200) that is broadly consistent with unperturbed systems, but neither population has reached a relaxed state. Our findings indicate that while the magnitude gap effectively identifies systems that have ceased major mergers in the last 3-6 Gyr, it is a poor proxy for their current global dynamical state, as reflected in the weak anticorrelation between Δ m_ 1,2 and D_̊m BSG-CM. The FS and non-FS populations exhibit intermediate gas-BSG offsets (D_ BSG-CM ≈ 0.15 R/R_ 200 ) and fail to reach relaxation. This decoupling suggests that the magnitude gap traces the assembly history of massive components and not the overall stability of the intracluster medium.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"68 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209042","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":"Extended gamma-ray emission in the vicinity of the Westerlund 1 massive star cluster and Kes 41 supernova remnant seen by the Fermi Large Area Telescope","authors":"L. Tibaldo,R. Bernet,L. Härer,M. Lemoine-Goumard,L. Mohrmann,G. Peron,B. Reville,T. Vieu","doi":"10.1051/0004-6361/202662016","DOIUrl":"https://doi.org/10.1051/0004-6361/202662016","url":null,"abstract":"There is growing evidence of cosmic-ray acceleration in massive stellar clusters. Furthermore, extended gamma-ray emission suggests that particle transport in the vicinity of their sources is influenced by physical processes markedly different from large-scale diffusion in the Milky Way. We characterize extended gamma-ray emission in the direction of the stellar cluster and supernova remnant using more than 16 years of data from the Large Area Telescope (LAT) at energies greater than 0.8 GeV. Westerlund 1 Kes 41 Fermi We tested whether clusters of gamma-ray sources not associated with multiwavelength counterparts are better described by extended emission components and characterized their spatial and spectral properties as well as their correlation with interstellar structures. We report the detection of three new extended emission components with soft spectra toward regions of high gas column density in the Galactic plane. One extended component is associated with the natal cloud of and is statistically preferred over the point source previously reported toward the supernova remnant shell. The other two overlap with neutral gas within ∼100 pc from the edge of the superbubble. The extended emission may be explained by either mismodeled gas in the interstellar background model or the local injection of particles. Under the latter hypothesis, explaining the component associated with requires converting łesssim 5% of the supernova remnant energy into accelerated particles, while accounting for the two components near requires converting 10^-4 of the cluster wind mechanical power into gamma rays. Kes 41 extended components Westerlund 1 Kes 41 Westerlund 1 More detailed physical modeling and more accurate observational constraints are needed to conclude whether the new extended emission components are due to particles that escap from and . Nevertheless, our results strengthen the evidence of gamma-ray emission structures arising at intermediate spatial scales between isolated objects and the large-scale diffuse emission from the interstellar medium. This could explain a part of the soft unassociated Galactic sources detected by ed Westerlund 1 Kes 41 LAT.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"33 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209047","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":"Solar wind interaction with the Martian magnetosphere under a radial interplanetary magnetic field black in the subsolar region","authors":"Sara Nesbit-Östman,Laila Andersson,Herbert Gunell,Shahab Fatemi,Steven Schwartz","doi":"10.1051/0004-6361/202659118","DOIUrl":"https://doi.org/10.1051/0004-6361/202659118","url":null,"abstract":"When supersonic solar wind encounters a conductive object, it can become subsonic, allowing for energy exchange between the local plasma and the solar wind. At objects such as Earth, this interaction primarily takes place in a collisionless shock. At Mars, there have been a number of studies where a shock has not been identified under a radial orientation of the interplanetary magnetic field (IMF). In this study, we investigate whether the flow becomes subsonic under radial IMF conditions and the nature of the transition. We used the 3D hybrid-kinetic model Amitis to investigate how the supersonic flow becomes subsonic for three different orientations of the IMF. The more radial the IMF becomes, the more upstream disturbances are found scattering the impinging solar wind, which decreases the solar wind momentum toward Mars, and the planetary plasma can expand to distances past the location of the nominal shock location. For a perfectly radial IMF, , and the impinging scattered solar wind interacts directly with the planetary plasma. black no shock forms in the subsolar region under the conditions we studied A radial orientation of the IMF greatly changes the interaction of the solar wind with the Martian magnetosphere such that the shock is not the only dominant process that decelerates the solar wind.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"26 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209049","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 occurrence rate of planets around subgiant stars from the TESS photometric survey","authors":"A. Dutta,P. Chaturvedi","doi":"10.1051/0004-6361/202659648","DOIUrl":"https://doi.org/10.1051/0004-6361/202659648","url":null,"abstract":"Subgiant stars represent a critical phase in stellar evolution, offering an opportunity to investigate how planetary systems respond to the early stages of post-main-sequence expansion. Despite their importance, systematic occurrence-rate studies of this population remain sparse compared with those of main-sequence and red-giant hosts. In this paper, we present a uniform analysis of planet occurrence around a sample of 282,904 subgiant stars selected from the Data Release 3 (DR3) catalogue. We performed an independent re-analysis of Transiting Exoplanet Survey Satellite (TESS) light curves for transit-signal detection and refinement, followed by multi-stage vetting including a visual inspection and statistical false-positive assessment. We quantified the detection sensitivity of the survey through injection-and-recovery experiments, with 565,808 synthetic transit signals injected across the stellar sample. Over the period range of 1--10 days and the planet-radius range for which the detection completeness is well characterised, we measure a completeness-corrected planet occurrence rate of 0.644^ Gaia +0.048 _ -0.041 %. The occurrence rate is strongly dependent on planet radius, with the highest occurrence contributed by planets in the 1--4,R_⊕ range and a secondary enhancement at 12--15,R_⊕. These results provide a demographic baseline for studying the population of close-in planets around stars undergoing early post-main-sequence evolution.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"56 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209114","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":"Gaussian process inference of stochastic magneto-active dynamics and viscosity in Swift J1727.8-1613","authors":"Lijuan Dong,Dahai Yan,Zihan Yang,Haiyun Zhang,Lin Xie,Qingcui Bu,Lian Tao","doi":"10.1051/0004-6361/202659872","DOIUrl":"https://doi.org/10.1051/0004-6361/202659872","url":null,"abstract":"Linking X-ray variability to the underlying magnetohydrodynamic (MHD) dynamics of black hole X-ray binaries remains challenging. We systematically investigate the stochastic and oscillatory variability of the black hole X-ray binary candidate Swift J1727.8-1613 during its 2023 outburst using Gaussian process (GP) regression applied to Insight-HXMT multi-band light curves. The variability is modelled with a physically motivated composite kernel comprising one stochastically driven damped simple harmonic oscillator (SHO) and two damped random walk (DRW) components. The SHO term robustly recovers quasi-periodic oscillations (QPOs) with frequencies ν_0 ∼ 0.07--5 Hz, consistent with the fundamental Alfvén mode of a contracting magnetically confined disk--coronal cavity. The quality factor rises from Q ∼ 3 to Q ∼ 10, suggesting increasing coherence of the magnetic cavity. We also find an anti-correlation between QPO frequency and the short DRW damping timescale, supporting our proposed stochastic magneto-active dynamics scenario. We associate the short and long DRW timescales with the local turbulent turnover and thermal adjustment timescales, respectively. Under this proposed interpretation, our results are consistent with an effective viscosity parameter α ∼ 0.1. Strikingly, near the jet-ejection epoch around MJD 60206, the short DRW timescale is unresolved, while the long DRW timescale approaches the 0.1 s sampling limit, suggesting a rapid reorganisation of the disk internal energy balance immediately before jet launching. Our results establish GP inference as a powerful route to connecting X-ray timing observables with the dynamical state of black hole accretion flows.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"76 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210369","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":"Magnetic connectivity from the Sun to the Earth with MHD models. II. Impact of input magnetic maps","authors":"B. Perri,S. Kennis,B. Schmieder,S. Poedts","doi":"10.1051/0004-6361/202662134","DOIUrl":"https://doi.org/10.1051/0004-6361/202662134","url":null,"abstract":"Magnetic connectivity is a method used to understand the connection between the Sun and the satellites orbiting around it. It is especially useful for Earth, as it helps us anticipate the propagation and geoeffectiveness of space weather events. Connectivity estimation needs to be fast (within 24 hours), and thus usually relies on semi-empirical models. In the first paper of this study, we established that optimised magnetohydrodynamics (MHD) models can also be used to derive magnetic connectivity, yielding good results, especially for complex configurations. However, the modelling is not the only factor that can impact the connectivity estimation. Models' results, both semi-empirical and MHD, depend heavily on the input data used to drive the simulation. The impact of the chosen input magnetic map has been studied for coronal and heliospheric models independently, but rarely together, and with a specific focus on magnetic connectivity. This knowledge is crucial to reducing the uncertainty associated with space weather forecasts. In order to quantify the impact of input magnetic maps on our connectivity estimation, we used 20 different maps by four providers, with various processing treatments. We selected the period of July 2019, which corresponds to Carrington rotation (CR) number 2219, because it had already been studied with COCONUT in a previous paper. It corresponds to a period of minimum activity, meaning minimal interference from transient structures, but with a high-speed stream and several polarity switches, making it interesting and challenging to model. We have compared our results with in situ data from ACE and developed several visualisation techniques to validate connectivity not only for a specific date but also for a full CR. The choice of the input magnetic map drastically affects the connectivity estimates, with global scores going from 28% global agreement to 63% in the most extreme case. The HMI and GONG maps consistently give the best connectivity estimations, with more than 50% correct results of the full CR. For this specific period, the GONG-ADAPT maps yield the least reliable results, with a score of below 35%. This is not surprising, as we have shown before that COCONUT required parameter adjustments for these maps. However, WSO maps that show poor coronal agreement actually provide good connectivity estimates, showing that the heliospheric current sheet (HCS) location is in the end the most crucial parameter for connectivity (compared to open field areas locations or streamer shape). We have confirmed with this study that minimum of activity cases are actually challenging for magnetic connectivity, due to the proximity of the HCS with Earth's position. Consistent data over a full CR are to be favoured compared to daily updates (which proved more unstable in terms of connectivity), or even high-resolution.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"7 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209043","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":"CHEX-MATE: Density profile reconstruction in galaxy clusters","authors":"I. Bartalucci,G. W. Pratt,E. Rasia,M. Arnaud,R.T. Duffy,Y. E. Bahar,M. Balboni,E. Baraldi,R. M. Batalha,A. Bonafede,H. Bourdin,F. De Luca,M. De Petris,S. Ettori,A. Ferragamo,M. Gaspari,F. Gastaldello,M. Gitti,A. Iqbal,M. Lepore,S. T. Kay,L. Lovisari,P. Mazzotta,B. J. Maughan,F. Oppizzi,E. Pointecouteau,M. Rossetti,J. Sayers,M. Sereno","doi":"10.1051/0004-6361/202662344","DOIUrl":"https://doi.org/10.1051/0004-6361/202662344","url":null,"abstract":"We investigated the reconstruction of the intra-cluster medium radial density profiles in galaxy clusters, focusing on the impact of cluster morphology, dynamical state, and methodological choices, within the framework of the ̧hxmate project. Using a sample of 109 simulated galaxy clusters analysed along 40 independent lines of sight, we compared azimuthal mean and median techniques for deprojection. We find that azimuthal median-based density profiles recover the true gas density with negligible bias over the radial range 0.15-1.3 R_ 500 $. Mean based profiles are affected by the presence of substructures. While an accurate masking of clumps or substructures can reduce the bias to $< 5%$, the discrepancy increases substantially in disturbed systems or when substructures remain unresolved. The mean-to-median density ratio statistically traces projected gas inhomogeneities, although intrinsic scatter and projection effects limit its use for individual clusters. The complementary use of mean and median profiles therefore provides the most complete approach for large X-ray cluster samples.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"482 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149210358","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 Volans-Carina association. An X-ray bridge between younger and older stellar populations","authors":"Daniela Muñoz-Giraldo,Beate Stelzer,Alex Binks,Enza Magaudda,Stefanie Raetz,Christian Schneider","doi":"10.1051/0004-6361/202661863","DOIUrl":"https://doi.org/10.1051/0004-6361/202661863","url":null,"abstract":"Nearby young moving groups (NYMGs) provide vital benchmarks for studying the evolution of magnetic activity and planetary environments at early ages. The pre-main sequence Volans-Carina association (VCA), at a distance of ∼90,pc, occupies a sparsely sampled region of parameter space between younger nearby associations and older distant open clusters. We aim to reassess the census of the VCA and present the first nearly complete X-ray characterization of a NYMG. We used updated kinematics from Gaia DR3 to reevaluate membership probabilities for VCA candidates using the BANYAN Σ code. We combined stellar parameters, derived from multiwavelength spectral energy distributions, with evolutionary models to obtain an isochronal age. We merged data from the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) on board the Spektrum-Roentgen-Gamma (SRG) and ROSAT all-sky surveys with our new dedicated XMM-Newton Large Programme to construct a comprehensive X-ray catalog. Our updated census of the VCA comprises 29 highly probable members, 30 (less secure) candidates, and four objects whose status is questionable. We find an isochronal age of 80 /L_ consistent with previous estimates. We detect X-ray emission from 56 objects, reaching an X-ray-detection completeness of sim90% for the currently known VCA stars. Low-mass members and candidates (łesssim0.6,M_⊙) have X-ray to bolometric luminosity ratios around the canonical saturation limit (L_ ̊m x ̊m bol ≈ 10 -3 ). X-ray luminosity functions show the VCA to be consistent with the similarly aged Pleiades (in the F5 to M3 range) and significantly more active than the older Hyades (in the F5 to K4 range). The combination of an updated membership census and a nearly complete X-ray census establishes the VCA as a particularly robust calibration point for studies of the early evolution of coronal X-ray activity.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"11 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209120","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":"Flashing with colours: Photometric indicators of an early interaction in type II supernovae","authors":"A. Mendez-Llorca,G. Folatelli,C. P. Gutiérrez,K. Ertini,C. R. Burns,N. Morrell,M. D. Stritzinger,M. Bersten,J. M. DerKacy,L. Ferrari,L. Galbany,J. T. Hinkle,W. B. Hoogendam,M. A. Tucker,C. Ashall,K. Auchettl,E. Y. Hsiao,K. Medler,C. Pfeffer,H. Xiao","doi":"10.1051/0004-6361/202661063","DOIUrl":"https://doi.org/10.1051/0004-6361/202661063","url":null,"abstract":"We present early-time optical photometry and spectroscopy for a sample 27 previously unpublished type II supernovae (SNe II) observed by the Precision Observations of Infant Supernova Explosions (POISE) collaboration, combined with a literature sample of 59 events to form a total sample of 86 objects. The resulting light curves comprise near-daily cadence, percent-level precision photometry. From spectra acquired within four days of the estimated explosion time, transient narrow emission lines of highly ionised elements, referred to as `flash features', can be identified. Based on the presence or absence of these lines, the SNe were categorised. We estimate key photometric properties, including rise times, peak absolute magnitude, and colour evolution. Our tests indicate that flash SNe are, on average, more luminous at the peak than their non-flash counterparts, which is consistent with previous studies. Interestingly, statistically significant differences were found in the rise times in the B band, with flash SNe exhibiting a tail towards longer rise times. Flash SNe are generally bluer than non-flash events, with distinct colour distributions at 20 days post explosion, likely reflecting intrinsic differences rather than host-galaxy extinction. Colour-curve breaks within 30 days of explosion provide a clear separation between flash and non-flash SNe. The change in slopes across the break, combined with the absolute peak magnitude, yield a strong diagnostic of the flash-spectroscopic properties. This indicates that photometric observations alone may be used to identify SNe experiencing an interaction with dense circumstellar material, even in the absence of early-time spectroscopy. uBgVri","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"26 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149209156","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}