Astronomy & Astrophysics最新文献

{"title":"Can primordial black holes explain the overabundance of bright super-early galaxies?","authors":"Antonio Matteri, Andrea Pallottini, Andrea Ferrara","doi":"10.1051/0004-6361/202553701","DOIUrl":"https://doi.org/10.1051/0004-6361/202553701","url":null,"abstract":"The James Webb Space Telescope (JWST) is detecting an excess of high-redshift (<i>z<i/> ≳ 10) bright galaxies that challenge most theoretical predictions. To address this issue, we investigated the impact of primordial black holes (PBHs) on the halo mass function and UV luminosity function (LF) of super-early galaxies. We explored two key effects: (i) The enhancement of the massive halo abundance due to the compact nature and spatial distribution of PBHs, and (ii) the luminosity boost, characterized by the Eddington ratio <i>λ<i/><sub>E<sub/>, caused by active galactic nuclei (AGN) that are powered by matter accretion onto PBHs. We built an effective model, calibrated using data at lower redshifts (<i>z<i/> ≈ 4 − 9), to derive the evolution of the LF, including the additional PBH contribution. A Bayesian analysis yielded the following results: (a) Although a small fraction (log <i>f<i/><sub>PBH<sub/> ≈ −5.42) of massive (log <i>M<i/><sub>PBH<sub/>/M<sub>⊙<sub/> ≈ 8.37) nonemitting (<i>λ<i/><sub>E<sub/> = 0) PBHs can explain the galaxy excess via the halo abundance enhancement, this solution is excluded by cosmic microwave background <i>μ<i/>-distortion constraints on monochromatic PBHs. (b) If PBHs power an AGN that emits at super-Eddington luminosity (<i>λ<i/><sub>E<sub/> ≈ 10), the observed LF can be reproduced by a PBH population with a characteristic mass log <i>M<i/><sub>PBH<sub/>/M<sub>⊙<sub/> ≈ 3.69, constituting a tiny (log <i>f<i/><sub>PBH<sub/> ≈ −8.16) fraction of the cosmic dark matter content. In the AGN scenario, about 75% of the observed galaxies with <i>M<i/><sub>UV<sub/> = −21 at <i>z<i/> = 11 should host a PBH-powered AGN and typically reside in low-mass halos, <i>M<i/><sub>h<sub/> = 10<sup>8 − 9<sup/> M<sub>⊙<sub/>. These predictions can be tested with available and forthcoming JWST spectroscopic data. We note that our analysis considered a lognormal PBH mass function and compared its parameters with monochromatic limits on the PBH abundance. Further work is required to relax these limitations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"16 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920824","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":"3D non-LTE Ca II line formation in metal-poor FGK stars","authors":"C. Lagae, A. M. Amarsi, K. Lind","doi":"10.1051/0004-6361/202452874","DOIUrl":"https://doi.org/10.1051/0004-6361/202452874","url":null,"abstract":"<i>Context.<i/> The Ca II near-ultraviolet resonance doublet (H&K) and the near-infrared triplet (CaT) are among the strongest features in stellar spectra of FGK-type stars. These spectral lines remain prominent down to extremely low metallicities and are thus useful for providing stellar parameters via ionisation balance, for Galactic chemical evolution, and as radial velocity diagnostics. However, the majority of studies that model these lines in late-type stars still rely on simplified one-dimensional (1D) hydrostatic model atmospheres and the assumption of local thermodynamic equilibrium (LTE).<i>Aims.<i/> We present 3D non-LTE radiative transfer calculations of the CaT and H&K lines in an extended grid of 3D model atmospheres of a metal-poor FGK type. We investigated the impact of 3D non-LTE effects on abundances, line bisectors, and radial velocities.<i>Methods.<i/> We used a subset of 3D model atmospheres from the recently published STAGGER-grid to synthesise spectra in 3D (non-)LTE with Balder for nine different calcium-to-iron ratios. For comparison, similar calculations were performed in 1D (non-)LTE using models from the MARCS grid.<i>Results.<i/> Abundance corrections for the CaT lines relative to 1D LTE range from +0.1≳Δ<sub>1L<sub/><sup>3N<sup/>≳−1.0 dex, with more severe corrections for strong lines in giants. With fixed line strength, the abundance corrections become more negative with increasing effective temperature and decreasing surface gravity. Radial velocity corrections relative to 1D LTE based on cross-correlation of the whole line profile range from −0.2 kms<sup>−1<sup/> to +1.5 kms<sup>−1<sup/>, with more severe corrections where the CaT lines are strongest. The corrections are even more severe if the line core alone is used to infer the radial velocity.<i>Conclusions.<i/> The line strengths and shapes, and consequently the abundance and radial velocity corrections, are strongly affected by the chosen radiative transfer assumption, 1/3D (non)-LTE. We release grids of theoretical spectra that can be used to improve the accuracy of stellar spectroscopic analyses based on the Ca II triplet lines.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"48 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920896","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":"Abundance analysis of stars hosting gas-rich debris discs","authors":"Sandipan P. D. Borthakur, Mihkel Kama, Luca Fossati, Quentin Kral, Colin P. Folsom, Johanna Teske, Anna Aret","doi":"10.1051/0004-6361/202452840","DOIUrl":"https://doi.org/10.1051/0004-6361/202452840","url":null,"abstract":"<i>Context.<i/> Accretion from protoplanetary or debris discs can contaminate the stellar photosphere, especially in stars that have radiative envelopes. Due to the relatively slower photospheric mixing, these stars can exhibit clear contamination signatures. The contaminated photosphere reflects ongoing disc processes, which are detectable through stellar spectroscopy.<i>Aims.<i/> We investigate the composition of six gas-rich debris disc-hosting A-type stars to understand possible links with their debris disc or earlier accretion stages.<i>Methods.<i/> We used archival spectra and the ZEEMAN spectral synthesis code to estimate the stellar parameters and abundances of six debris disc-hosting A-type stars. We also estimated the stellar photospheric accretion contamination parameter, <i>f<i/><sub>ph<sub/>, using CAMSTARS, which indicates the fraction of accreting material on the stellar photosphere.<i>Results.<i/> The oxygen abundance in intermediate-mass stars decreases with age until the debris disc stage (<20 Myr), after which it could end up rising. The downward trend could result from H<sub>2<sub/>O ice accumulating in dust traps or the formation of hydrated asteroids in the protoplanetary disc, locking oxygen in solids and reducing its accretion onto the star. All the stars share similar volatile abundances (C, O), but HD 110058 and HD 32297 exhibit refractory depleted abundances. The near-zero <i>f<i/><sub>ph<sub/> values in the six stars suggest that any currently accreted gas would not overwhelm mixing in the photosphere and would not impact the observed composition. The refractory depleted abundances in HD 110058 and HD 32297 suggest residual or even chronic, accretion contamination from their earlier protoplanetary stages when the accretion rates were about five orders of magnitude higher. For HD 110058, with the highest refractory depletion, we estimated a lower limit on its earlier protoplanetary accretion rate of 9 × 10<sup>−8<sup/> <i>M<i/><sub>⊙<sub/>/yr, similar to other Herbig stars and equal to the Herbig star HD 100546. This supports our hypothesis that refractory depletion in HD 110058 originates from a prior phase of higher accretion of dust-poor material. We further develop this hypothesis by comparing HD 110058 with the HD 100546 protoplanetary disc system, which is of a similar age.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"68 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920897","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":"Dynamic atmosphere and wind models of C-type asymptotic giant branch stars","authors":"E. Siderud, K. Eriksson, S. Höfner, S. Bladh","doi":"10.1051/0004-6361/202347642","DOIUrl":"https://doi.org/10.1051/0004-6361/202347642","url":null,"abstract":"<i>Context.<i/> Mass loss through stellar winds governs the evolution of stars on the asymptotic giant branch (AGB). In the case of carbonrich AGB stars, the wind is believed to be driven by radiation pressure on amorphous carbon (amC) dust forming in the atmosphere. The structural complexity of amC is evident from the diversity of laboratory optical data that are available in the literature. Consequently, the choice of dust optical data will have a significant impact on atmosphere and wind models of AGB stars.<i>Aims.<i/>We compare two commonly used optical data sets of amC and investigate how the wind characteristics and photometric properties resulting from dynamical models of carbon-rich AGB stars are influenced by the micro-physical properties of dust grains.<i>Methods.<i/> We computed two extensive grids of carbon star atmosphere and wind models with the DARWIN 1D radiation-hydrodynamical code. A defining feature of these models is a self-regulating feedback between the time-dependent dynamics, grain growth, and dust optical properties. Thus, they are able to predict combinations of mass-loss rates, wind velocities, and grain sizes for given stellar parameters and micro-physical data. Each of the two grids uses a different amC optical data set. The stellar parameters of the models were varied in terms of the effective temperature, luminosity, stellar mass, carbon excess, and pulsation amplitude to cover a wide range of possible combinations. A posteriori radiative transfer calculations were performed for a sub-set of the models, resulting in photometric fluxes and colours.<i>Results.<i/> We find small, but systematic differences in the predicted mass-loss rates for the two grids. The grain sizes and photometric properties are affected by the different dust optical data sets. Higher absorption efficiency leads to the formation of a greater number of grains, which are smaller. Models that are obscured by dust exhibit differences in terms of the covered colour range compared to observations, depending on the dust optical data used.<i>Conclusions.<i/> An important motivation for this study was to investigate how strongly the predicted mass-loss rates depend on the choice of dust optical data, as these mass-loss values are more frequently used in stellar evolution models. Based on the current results, we conclude that mass-loss rates may typically differ by about a factor of two for DARWIN models of C-type AGB stars for commonly used dust optical data sets.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"26 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920898","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":"Diffusive versus non-diffusive paths to interstellar hydrogen peroxide","authors":"J. Poštulka, P. Slavíček, J. Kästner, G. Molpeceres","doi":"10.1051/0004-6361/202452617","DOIUrl":"https://doi.org/10.1051/0004-6361/202452617","url":null,"abstract":"<i>Context.<i/> Radical chemical reactions on cosmic dust grains play a crucial role in forming various chemical species. Among different radicals, the hydroxyl (OH) is one of the most important, with a rather specific chemistry.<i>Aims.<i/> The goal of this work is to simulate the recombination dynamics of hydroxyl radicals and the subsequent formation of hydrogen peroxide (H<sub>2<sub/>O<sub>2<sub/>).<i>Methods.<i/> We employed neural-network potentials trained on ONIOM(QM/QM) data, combining multi-reference (CASPT2) and density functional theory calculations. This approach allowed us to model the recombination of hydroxyl radicals on ice surfaces with high computational efficiency and accuracy.<i>Results.<i/> Our simulations reveal that the initial position of the radicals plays a decisive role in determining recombination probability. We found that the formation of a hydrogen bond between radicals competes with the formation of hydrogen peroxide, reducing the recombination efficiency, which is contrary to what was expected. This competition reduces the recombination probability for radicals that are initially formed approximately 3 Å apart. Recombination probabilities also depend on the kinetic energy of the added radicals, with values around 0.33 for thermal radicals and a wide range of values between 0.33 and 1.00 for suprathermal OH radicals.<i>Conclusions.<i/> Based on our calculations, we provide recommendations for introducing OH radical recombination into kinetic astrochemical models, differentiating between thermal and suprathermal radicals. The recombination behaviour varies significantly between these two cases: while thermal radicals are sometimes trapped in hydrogen-bonded minima, the case of suprathermal radicals varies with the added energy. Our most important conclusion is that OH radical recombination probability cannot be assumed to be 1.0 for a wide variety of cases.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"7 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920899","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 jet and circumstellar environment of the young binary DF Tau","authors":"A. V. Dodin, M. A. Burlak, V. A. Kiryukhina, S. A. Lamzin, I. A. Shaposhnikov, I. A. Strakhov, A. A. Tatarnikov, A. M. Tatarnikov","doi":"10.1051/0004-6361/202554711","DOIUrl":"https://doi.org/10.1051/0004-6361/202554711","url":null,"abstract":"<i>Context.<i/> Jets and disk winds play an important role in the evolution of protoplanetary disks and the formation of planetary systems. However, there is still a lack of observational data regarding the presence and parameters of outflows, especially for close young binaries.<i>Aims.<i/> In this study, we aim to find the HH flow near the young sub-arcsecond binary DF Tau and explore its morphology.<i>Methods.<i/> We performed narrow-band H<i>α<i/> and H<sub>2<sub/> 2.12 μm imaging and spectroscopic observations of DF Tau and its vicinity.<i>Results.<i/> We discovered several emission nebulae near the binary, which likely result from the interaction of gas outflow from the binary components with the surrounding medium. The outflow appears to occur both in the form of jets, generating numerous Herbig-Haro objects (HH 1266 flow), and as a weakly collimated wind responsible for the formation of the ring-like nebula around the binary and the rim of the cometary globule. We find that the angle between the jet and the counter-jet is 168° and provide a discussion on the complex morphology of the HH flow.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"48 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920827","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":"Comparing the Sun to Sun-like stars","authors":"Konstantin Herbst, Eliana M. Amazo-Gómez, Athanasios Papaioannou","doi":"10.1051/0004-6361/202452999","DOIUrl":"https://doi.org/10.1051/0004-6361/202452999","url":null,"abstract":"<i>Context.<i/> Whether the Sun is an ordinary G-type star is still an open scientific question. Stellar surveys by <i>Kepler<i/> and <i>TESS<i/>, however, have revealed that Sun-like stars tend to show much stronger flare activity than the Sun.<i>Aims.<i/> This study aims to reassess observed flare and spot activity of Sun-like <i>Kepler<i/> stars by fine-tuning the criteria for a more robust definition of Sun-like conditions and better comparability between the current Sun and Sun-like stars.<i>Methods.<i/> We updated one of the recent stellar Sun-like star samples by applying new empirical stellar relations between the starspot size and the effective stellar temperature to derive more reliable starspot group sizes. From the 265 solar-type stars, we found 48 stars supporting <i>Kepler<i/> 30-minute-cadence light curves. We analyzed these 48 by implementing the gradient of the power spectra method to distinguish between spot- and faculae-dominated stars. We employed the <i>α<i/> factor to quantify the area ratio of bright and dark features on the stellar surface.<i>Results.<i/> We were able to determine which of the 48 stars were spot- or faculae-dominated. Our results revealed a preferential distribution of <i>Kepler<i/> Sun-like stars toward the spot-dominated (44 stars) and transitional (4 stars) regimes. As the current Sun is faculae-dominated, only the transitional stars were utilized for further evaluation. Additionally, accounting for comparability in stellar mass, radius, and rotation period, we show that only 1 of the 265 Sun-like stars in the <i>Kepler<i/> sample (i.e., KIC 11599385) can be directly compared to the current Sun. We further show that the single flare observed on KIC 11599385 falls right within the flare energy range estimated for the AD774/775 event observed in the cosmogenic radionuclide archives of <sup>10<sup/>Be, <sup>14<sup/>C, and <sup>36<sup/>Cl.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"23 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920895","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":"A Sequoia stellar candidate with very high 7Li and 9Be","authors":"L. Monaco, E. Caffau, P. Molaro, P. Bonifacio, G. Cescutti","doi":"10.1051/0004-6361/202453574","DOIUrl":"https://doi.org/10.1051/0004-6361/202453574","url":null,"abstract":"<i>Aims.<i/> The metal-poor star BPM 3066 belongs to the retrograde halo and presents unexpectedly strong spectral features of lithium. To gain insight into the origin of this peculiar abundance, we investigate the chemistry and kinematic properties of this star.<i>Methods.<i/> We performed a local thermodynamic equilibrium chemical abundance analysis of UVES/VLT high-resolution spectra of BPM 3066 using ATLAS9 and ATLAS12 model atmospheres and the MyGIsFOS code. We further characterised the orbital properties of the star by integrating its orbit and analysing its integrals of motion using the galpy code.<i>Results.<i/> The star BPM 3066 shows an exceptional overabundance of both lithium and beryllium. The abundances are A(Li) = 3.0 and A(Be) = 2.1, which are respectively about 0.8 and 2.2 dex higher than the Li and Be abundances expected at [Fe/H] = −1.5, the metallicity of the star. The observed ratio <sup>7<sup/>Li/<sup>9<sup/>Be is 7.9, which is close to that expected from a synthesis by spallation processes. Overabundances of Si, Al, and of the neutron capture elements Sr,Y, Zr, and Ba are also measured. Kinematically, BPM 3066 has an eccentric, strongly retrograde orbit, confined to a height lower than 1 kpc from the galactic plane, and it is a candidate member of the Sequoia/Thamnos accreted galaxy.<i>Conclusions.<i/> The processes leading to the <sup>7<sup/>Li and <sup>9<sup/>Be synthesis could have occurred in the environment of a hypernova. This is supported by some abundance anomalies like the high value of Si, [Si/Fe] = 1.2 and [Si/O] = 1.1. However, the simultaneous high values of N, Na, Al, Sc, Ti, and Cu are at odds with the expectations from a hypernova. Alternatively, the abundances of BPM 3066 could result from the engulfing of rocky planets that were rich in spallated Li and Be. In both cases, it is remarkable that such an extreme abundance pattern has been found in a star belonging to the Sequoia/Thamnos accreted galaxy.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"117 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920823","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":"AT2021uey: A planetary microlensing event outside the Galactic bulge","authors":"M. Ban, P. Voloshyn, R. Adomavic̆ienė, E. Bachelet, V. Bozza, S. M. Brincat, I. Bruni, U. Burgaz, J. M. Carrasco, A. Cassan, V. C̆epas, F. Cusano, M. Dennefeld, M. Dominik, F. Dubois, R. Figuera Jaimes, A. Fukui, C. Galdies, A. Garofalo, M. Hundertmark, I. Ilyin, K. Kruszyńska, V. Kulijanishvili, T. Kvernadze, L. Logie, M. Maskoliūnas, P. J. Mikołajczyk, P. Mróz, N. Narita, E. Paks̆tienė, J. Peloton, R. Poleski, J. K. T. Qvam, S. Rau, P. Rota, K. A. Rybicki, R. A. Street, Y. Tsapras, S. Vanaverbeke, J. Wambsganss, Ł. Wyrzykowski, J. Zdanavic̆ius, M. Żejmo, P. Zieliński, S. Zola","doi":"10.1051/0004-6361/202554236","DOIUrl":"https://doi.org/10.1051/0004-6361/202554236","url":null,"abstract":"We report the analysis of a planetary microlensing event AT2021uey. The event was observed outside the Galactic bulge and alerted both space-(<i>Gaia<i/>) and ground-based (ZTF and ASAS-SN) surveys. From the observed data, we find that the lens system is located at a distance of ∼1 kpc and comprises an M-dwarf host star of about half a solar mass, orbited by a Jupiter-like planet beyond the snowline. The source star could be a metal-poor giant located in the halo according to the spectral analyses and modelling. Hence, AT2021uey is a unique example of the binary-lens event outside the bulge that is offered by a disc-halo lens-source combination.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"27 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920894","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 MIRI/MRS Library","authors":"Danny Gasman, Ioannis Argyriou, David R. Law, Alistair Glasse, Karl D. Gordon, Patrick J. Kavanagh, Jane E. Morrison, Polychronis Patapis, Gregory C. Sloan","doi":"10.1051/0004-6361/202554055","DOIUrl":"https://doi.org/10.1051/0004-6361/202554055","url":null,"abstract":"&lt;i&gt;Context&lt;i/&gt;. The Medium Resolution Spectrometer (MRS) of the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) is affected by interferometric spectral fringing, due to scattering within the detector and dichroic layers. The amplitude of these oscillations on the spectrum can be up to 30%. Correcting them is non-trivial, since the depth and phase of the fringes depend strongly on the illumination pattern and the way the pixels sample it. By default the JWST pipeline uses static fringe flats to divide out the fringes. These flats are representative for a spatially homogeneous extended source, but not for point sources. The significant residuals in the data are removed by using a self-calibrating correction step which can alter physical features in the spectra in a non-systematic way.&lt;i&gt;Aims&lt;i/&gt;. We build on our corrections from Paper I (, A&A, 688, A226) in this series, to derive a library of detector-based fringe flats for unresolved sources in a nine-point mosaic around all nominal MRS point source dither positions. We provide users with either an absolute or interpolated fringe flat that can correct the fringes without the need for self-calibration, hence mitigating the risk of altering astrophysical features of interest.&lt;i&gt;Methods&lt;i/&gt;. We used the data of 10 Lac from the Cycle 2 calibration programme 3779 to create the library of fringe flats. By removing the continuum and spectral features from the data at the detector-plane level, each of the nine mosaic points around the eight dither positions resulted in a pointing specific fringe flat. By assessing the difference in response between the individual pointings, we found correction factors to bring all the spectra to the same level, and used these to derive a single spectrophotometric calibration curve per band.&lt;i&gt;Results&lt;i/&gt;. The library of fringe flats is able to reduce the remaining power of the fringe frequencies on the detector by up to two orders of magnitude compared to the current pipeline flats tailored to extended sources. This improvement carries over to the residuals in the cube spaxels, where the contrast is reduced from &gt;10% to &lt;1−2%. This becomes less apparent after extracting a spectrum from the cube, where in channel 1 averaging of fringe phases in the current pipeline case can reduce its residual contrast. The spectrophotometric calibration curves have a root-mean squared variation of less than a percent in all bands except bands 4B and 4C, while channels 2 and 3 have a stability within 0.5%. Sources taken without target acquisition (TA) fall outside the mosaic grid, but our correction improves the defringing depending on the source location.&lt;i&gt;Conclusions&lt;i/&gt;. The improvements in fringe residual found are significant on the detector and spectrum-level. The corrections derived here are directly compatible with the current JWST pipeline infrastructure, and work best for unresolved sources observed with TA in one of the nominal point-source dither patte","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"49 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143920900","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}