Astronomy & Astrophysics最新文献

{"title":"Water depletion and 15NH3 in the atmosphere of the coldest brown dwarf observed with JWST/MIRI","authors":"H. Kühnle, P. Patapis, P. Mollière, P. Tremblin, E. Matthews, A. M. Glauser, N. Whiteford, M. Vasist, O. Absil, D. Barrado, M. Min, P.-O. Lagage, L. B. F. M. Waters, M. Guedel, Th. Henning, B. Vandenbussche, P. Baudoz, L. Decin, J. P. Pye, P. Royer, E. F. van Dishoeck, G. Östlin, T. P. Ray, G. Wright","doi":"10.1051/0004-6361/202452547","DOIUrl":"https://doi.org/10.1051/0004-6361/202452547","url":null,"abstract":"<i>Context.<i/> With a temperature of ∼285 K, WISEJ0855–0714 (hereafter, WISE 0855) is the coldest brown dwarf observed thus far. Studying such cold gas giants allows us to probe the atmospheric physics and chemistry of evolved objects that resemble Solar System gas giants.<i>Aims.<i/> Using <i>James Webb<i/> Space Telescope (JWST), we obtained observations to characterize WISE 0855’s atmosphere, focusing on vertical variation in the water steam abundance, measuring trace gas abundances, and obtaining the bulk parameters for this cold object.<i>Methods.<i/> We observed the ultra-cool dwarf WISE 0855 using the Mid-Infrared Instrument Medium Resolution Spectrometer (MIRI/MRS) on board JWST at a spectral resolution of up to 3750. We combined the observation with published data from the Near-Infrared Spectrograph (NIRSpec) G395M and PRISM modes, yielding a spectrum ranging from 0.8 to 22 µm. We applied atmospheric retrievals using <mono>petitRADTRANS</mono> to measure the atmospheric abundances, pressure-temperature structure, radius, and gravity of the brown dwarf. We also employed publicly available clear and cloudy self-consistent grid models to estimate the bulk properties of the atmosphere such as the effective temperature, radius, gravity, and metallicity.<i>Results.<i/> Atmospheric retrievals have constrained a variable water abundance profile in the atmosphere, as predicted by equilibrium chemistry. We detected the <sup>15<sup/>NH<sub>3<sub/> isotopolog and inferred a ratio of volume fraction of <sup>14<sup/>NH<sub>3<sub/>/<sup>15<sup/> NH<sub>3<sub/> = 349<sub>−41<sub/><sup>+53<sup/> for the clear retrieval. We measured the bolometric luminosity by integrating the presented spectrum, obtaining a value of log(L/L<sub>⊙<sub/>) = −7.291 ± 0.008.<i>Conclusions.<i/> The detected water depletion indicates that water condenses out in the upper atmosphere due to the very low effective temperature of WISE 0855. The height in the atmosphere where this occurs is covered by the MIRI/MRS data, thereby demonstrating the potential of MIRI to characterize the atmospheres of cold gas giants. After comparing the data to retrievals and self-consistent grid models, we did not detect any signs of water ice clouds, although their spectral features have been predicted in previous studies.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"28 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703056","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":"Turbulent fragmentation as the primary driver of core formation in Polaris Flare and Lupus I⋆","authors":"Kousuke Ishihara, Fumitaka Nakamura, Patricio Sanhueza, Masao Saito","doi":"10.1051/0004-6361/202452427","DOIUrl":"https://doi.org/10.1051/0004-6361/202452427","url":null,"abstract":"<i>Context.<i/> Stars form from dense cores in turbulent molecular clouds. According to the standard scenario of star formation, dense cores are created by cloud fragmentation. However, the physical mechanisms driving this process are still not fully understood from an observational standpoint.<i>Aims.<i/> Our goal is to investigate the process of cloud fragmentation using observational data from nearby clouds. Specifically, we aim to examine the role of self-gravity and turbulence, both of which are key to the dynamical evolution of clouds.<i>Methods.<i/> We applied astrodendro to the <i>Herschel<i/> H<sub>2<sub/> column density maps to identify dense cores and determine their mass and separation in two nearby low-mass clouds: the Polaris Flare and Lupus I clouds. We then compared the observed core masses and separations with predictions from models of gravitational and turbulent fragmentation. In the gravitational fragmentation model, the characteristic length and mass are determined by the Jeans length and Jeans mass. For turbulent fragmentation, the key scales are the cloud’s sonic scale and its corresponding mass.<i>Results.<i/> The average core masses are estimated to be 0.242 <i>M<i/><sub>⊙<sub/> for Lupus I and 0.276 <i>M<i/><sub>⊙<sub/> for the Polaris Flare. The core separations peak at about 2 − 4 × 10<sup>4<sup/> au (≈0.1–0.2 pc) in both clouds. These separations are significantly smaller than the Jeans length but agree well with the cloud sonic scale. Additionally, the density probability distribution functions of the dense cores follow log-normal distributions, which is consistent with the predictions of turbulent fragmentation.<i>Conclusions.<i/> These findings suggest that the primary process driving core formation in the observed low-mass star-forming regions is not gravitational fragmentation but rather turbulent fragmentation. We found no evidence that filament fragmentation plays a significant role in the formation of dense cores.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"183 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702924","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":"Modelling methanol and hydride formation in the JWST Ice Age era","authors":"Izaskun Jiménez-Serra, Andrés Megías, Joseph Salaris, Herma Cuppen, Angèle Taillard, Miwha Jin, Valentine Wakelam, Anton I. Vasyunin, Paola Caselli, Yvonne J. Pendleton, Emmanuel Dartois, Jennifer A. Noble, Serena Viti, Katerina Borshcheva, Robin T. Garrod, Thanja Lamberts, Helen Fraser, Gary Melnick, Melissa McClure, Will Rocha, Maria N. Drozdovskaya, Dariusz C. Lis","doi":"10.1051/0004-6361/202452389","DOIUrl":"https://doi.org/10.1051/0004-6361/202452389","url":null,"abstract":"&lt;i&gt;Context.&lt;i/&gt; Recent JWST observations have measured the ice chemical composition towards two highly extinguished background stars, NIR38 and J110621, in the Chamaeleon I molecular cloud. The observed excess of extinction on the long-wavelength side of the H&lt;sub&gt;2&lt;sub/&gt;O ice band at 3 μm has been attributed to a mixture of CH&lt;sub&gt;3&lt;sub/&gt;OH with ammonia hydrates NH&lt;sub&gt;3&lt;sub/&gt;·H&lt;sub&gt;2&lt;sub/&gt;O), which suggests that CH&lt;sub&gt;3&lt;sub/&gt;OH ice in this cloud could have formed in a water-rich environment with little CO depletion. Laboratory experiments and quantum chemical calculations suggest that CH&lt;sub&gt;3&lt;sub/&gt;OH could form via the grain surface reactions CH&lt;sub&gt;3&lt;sub/&gt; + OH and/or C + H&lt;sub&gt;2&lt;sub/&gt;O in water-rich ices. However, no dedicated chemical modelling has been carried out thus far to test their efficiency. In addition, it remains unexplored how the efficiencies of the proposed mechanisms depend on the astrochemical code employed.&lt;i&gt;Aims.&lt;i/&gt; We modelled the ice chemistry in the Chamaeleon I cloud to establish the dominant formation processes of CH&lt;sub&gt;3&lt;sub/&gt;OH, CO, CO&lt;sub&gt;2&lt;sub/&gt;, and of the hydrides CH&lt;sub&gt;4&lt;sub/&gt; and NH&lt;sub&gt;3&lt;sub/&gt; (in addition to H&lt;sub&gt;2&lt;sub/&gt;O). By using a set of state-of-the-art astrochemical codes (MAGICKAL, MONACO, Nautilus, UCLCHEM, and KMC simulations), we can test the effects of the different code architectures (rate equation vs. stochastic codes) and of the assumed ice chemistry (diffusive vs. non-diffusive).&lt;i&gt;Methods.&lt;i/&gt; We consider a grid of models with different gas densities, dust temperatures, visual extinctions, and cloud-collapse length scales. In addition to the successive hydrogenation of CO, the codes’ chemical networks have been augmented to include the alternative processes for CH&lt;sub&gt;3&lt;sub/&gt;OH ice formation in water-rich environments (i.e. the reactions CH&lt;sub&gt;3&lt;sub/&gt; + OH → CH&lt;sub&gt;3&lt;sub/&gt;OH and C + H&lt;sub&gt;2&lt;sub/&gt;O → H&lt;sub&gt;2&lt;sub/&gt;CO).&lt;i&gt;Results.&lt;i/&gt; Our models show that the JWST ice observations are better reproduced for gas densities ≥10&lt;sup&gt;5&lt;sup/&gt; cm&lt;sup&gt;−3&lt;sup/&gt; and collapse timescales ≥10&lt;sup&gt;5&lt;sup/&gt; yr. CH&lt;sub&gt;3&lt;sub/&gt;OH ice formation occurs predominantly (&gt;99%) via CO hydrogenation. The contribution of reactions CH&lt;sub&gt;3&lt;sub/&gt; + OH and C + H&lt;sub&gt;2&lt;sub/&gt;O is negligible. The CO&lt;sub&gt;2&lt;sub/&gt; ice may form either via CO + OH or CO + O depending on the code. However, KMC simulations reveal that both mechanisms are efficient despite the low rate of the CO + O surface reaction. CH&lt;sub&gt;4&lt;sub/&gt; is largely underproduced for all codes except for UCLCHEM, for which a higher amount of atomic C is available during the translucent cloud phase of the models. Large differences in the predicted abundances are found at very low dust temperatures (T&lt;sub&gt;dust&lt;sub/&gt;&lt;12 K) between diffusive and non-diffusive chemistry codes. This is due to the fact that non-diffusive chemistry takes over diffusive chemistry at such low T&lt;sub&gt;dust&lt;sub/&gt;. This could explain the rather constant ice chemical composition found in Chamaeleon I a","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"35 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702992","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":"Dissecting stellar populations with manifold learning","authors":"A. W. Neitzel, T. L. Campante, D. Bossini, A. Miglio","doi":"10.1051/0004-6361/202451718","DOIUrl":"https://doi.org/10.1051/0004-6361/202451718","url":null,"abstract":"<i>Context.<i/> Different stellar populations may be identified through differences in chemical, kinematic, and chronological properties, suggesting the interplay of various physical mechanisms that led to their origin and subsequent evolution. As such, the identification of stellar populations is key for gaining an insight into the evolutionary history of the Milky Way. This task is complicated by the fact that stellar populations share a significant overlap in their chrono-chemo-kinematic properties, hindering efforts to identify and define stellar populations.<i>Aims.<i/> Our goal is to offer a novel and effective methodology that can provide a deeper insight into the nonlinear and nonparametric properties of the multidimensional physical parameters that define stellar populations.<i>Methods.<i/> For this purpose, we explore the ability of manifold learning to differentiate stellar populations with minimal assumptions about their number and nature. Manifold learning is an unsupervised machine learning technique that seeks to intelligently identify and disentangle manifolds hidden within the input data. To test this method, we make use of <i>Gaia<i/> DR3-like synthetic stellar samples generated from the FIRE-2 cosmological simulations. These represent red-giant stars constrained by asteroseismic data from TESS.<i>Results.<i/> We reduced the 5D input chrono-chemo-kinematic parameter space into 2D latent space embeddings generated by manifold learning. We then study these embeddings to assess how accurately they represent the original data and whether they contain meaningful information that can be used to discern stellar populations.<i>Conclusions.<i/> We conclude that manifold learning possesses promising abilities to differentiate stellar populations when considering realistic observational constraints.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"93 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702926","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":"Investigating AGN feedback in Hα-luminous galaxy clusters: First Chandra X-ray analysis of Abell 2009","authors":"I. Fornasiero, F. Ubertosi, M. Gitti","doi":"10.1051/0004-6361/202453315","DOIUrl":"https://doi.org/10.1051/0004-6361/202453315","url":null,"abstract":"<i>Aims.<i/> We analyze the X-ray and radio properties of the galaxy cluster Abell 2009 (<i>z<i/> ∼ 0.152) to complete the in-depth individual study of a subsample of objects from the ROSAT Brightest Cluster Sample (BCS) with a relatively high X-ray flux and H<i>α<i/> line luminosity, which is a promising diagnostic of the presence of cool gas in the cluster cores. Our aim is to investigate the feedback from the active galactic nucleus (AGN) in the central galaxy and the intracluster medium (ICM) of relaxed clusters.<i>Methods.<i/> In this work, we analyze archival data from JVLA and <i>Chandra<i/> observations. We performed a morphological analysis of both the X-ray emission from the ICM of Abell 2009 and of the radio emission from the AGN in the central galaxy. We also performed a spectral analysis of the X-ray emission, to derive the global properties and radial profiles of the thermal gas.<i>Results.<i/> Our X-ray analysis confirms the expectations, based on the selection criteria, that Abell 2009 is a cool-core system. We estimate a cooling radius of ∼88 kpc within which the ICM is radiating away its energy at rates of <i>L<i/><sub>cool<sub/> ∼ 4.4 × 10<sup>44<sup/> erg s<sup>−1<sup/>. Radio observations of the central galaxy reveal a bright core surrounded by radio lobes on 30 kpc scales, with a symmetric butterfly-shaped morphology. We also present the detection of an extended radio galaxy to the northwest of the central one that is also a cluster member of Abell 2009. Although we did not detect any clear X-ray cavity at the position of the central radio lobes by assuming that their size is comparable, we combined the volume of the lobes with the pressure of the surrounding ICM to derive the work done by the AGN on the gas to inflate them. By estimating a cavity age of about 20 Myr, this corresponds to a mechanical power of ≈10<sup>45<sup/> erg s<sup>−1<sup/>, which is sufficient to counterbalance the radiative cooling losses in Abell 2009. We finally discuss possible correlations between the global properties of the 18 objects from the BCS selection, finding in particular that the number of outbursts required to counterbalance the radiative ICM losses is linearly anticorrelated with the energetics and power of the outburst.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"29 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702986","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 H I mass function of the Local Universe: Combining measurements from HIPASS, ALFALFA, and FASHI","authors":"Wenlin Ma, Hong Guo, Haojie Xu, Michael G. Jones, Chuan-Peng Zhang, Ming Zhu, Jing Wang, Jie Wang, Peng Jiang","doi":"10.1051/0004-6361/202452976","DOIUrl":"https://doi.org/10.1051/0004-6361/202452976","url":null,"abstract":"We present the first H I mass function (HIMF) measurement for the recent FAST All Sky H I (FASHI) survey and the most complete measurements of the HIMF in the Local Universe thus far. We obtained these results by combining the H I catalogues from H I Parkes All Sky Survey (HIPASS), Arecibo Legacy Fast ALFA (ALFALFA), and FASHI surveys at a redshift of 0 < <i>z<i/> < 0.05, covering 76% of the entire sky. We adopted the same methods to estimate the distances, calculate the sample completeness, and determine the HIMF for all three surveys. The best-fit Schechter function for the total HIMF shows a low-mass slope parameter of <i>α<i/> = −1.30 ± 0.01 and a ‘knee’ mass of along with a normalisation of <i>ϕ<i/><sub><i>s<i/><sub/> = (6.58 ± 0.23)×10<sup>−3<sup/> <i>h<i/><sub>70<sub/><sup>3<sup/> Mpc<sup>−3<sup/> dex<sup>−1<sup/>. This gives us the cosmic H I abundance: . We find that a double Schechter function with the same slope <i>α<i/> better describes our HIMF, where the two different ‘knee’ masses are and . We verify that the measured HIMF is marginally affected by the choice of distance estimates. The effect of cosmic variance is significantly suppressed by combining the three surveys and this provides a unique opportunity to obtain an unbiased estimate of the HIMF in the Local Universe.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"35 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703060","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":"Rediscovering the Milky Way with an orbit superposition approach and APOGEE data","authors":"Sergey Khoperskov, Glenn van de Ven, Matthias Steinmetz, Bridget Ratcliffe, Ivan Minchev, Davor Krajnović, Misha Haywood, Paola Di Matteo, Nikolay Kacharov, Léa Marques, Marica Valentini, Roelof S. de Jong","doi":"10.1051/0004-6361/202453304","DOIUrl":"https://doi.org/10.1051/0004-6361/202453304","url":null,"abstract":"We introduce a novel orbit superposition method designed to reconstruct the stellar density structure, kinematics, and chemical abundance distribution of the entire Milky Way by leveraging 6D phase-space information from its resolved stellar populations, limited by the spatial coverage of APOGEE DR17.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"57 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702879","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 helical magnetic field in quasar NRAO 150 revealed by Faraday rotation","authors":"J. D. Livingston, A. S. Nikonov, S. A. Dzib, L. C. Debbrecht, Y. Y. Kovalev, M. M. Lisakov, N. R. MacDonald, G. F. Paraschos, J. Röder, M. Wielgus","doi":"10.1051/0004-6361/202453056","DOIUrl":"https://doi.org/10.1051/0004-6361/202453056","url":null,"abstract":"<i>Context.<i/> Active galactic nuclei (AGN) are some of the most luminous and extreme environments in the Universe. The central engines of AGN are believed to be super-massive black-holes (SMBHs) are fed by accretion discs threaded by magnetic fields within a dense magneto-ionic medium.<i>Aims.<i/> We report our findings from polarimetric very-long-baseline interferometry (VLBI) observations of quasar NRAO 150 taken in October 2022 using a combined network of the Very Long Baseline Array (VLBA) and Effelsberg 100-m Radio Telescope. These observations comprise the first co-temporal multi-frequency polarimetric VLBI observations of NRAO 150 at frequencies above 15 GHz.<i>Methods.<i/> We used the new VLBI polarization calibration procedure, GPCAL, with polarization observations of frequencies of 12 GHz, 15 GHz, 24 GHz, and 43 GHz of NRAO 150. From these observations, we were able to measure the Faraday rotation and use it to derive the intrinsic electric vector position angle (EVPA<sub>0<sub/>) for the source. As a complementary measurement, we determined the behavior of polarization as a function of observed frequency.<i>Results.<i/> The polarization from NRAO 150 only comes from the core region, with a peak polarization intensity occurring at 24 GHz. Across the core region of NRAO 150, we see clear gradients in Faraday rotation and EVPA<sub>0<sub/> values that are aligned with the direction of the jet curving around the core region. We find that for the majority of the polarized region the polarization fraction is greater at higher frequencies, with intrinsic polarization fractions in the core ≈3%.<i>Conclusions.<i/> The Faraday rotation gradients and circular patterns in EVPA<sub>0<sub/> offer strong evidence to support the presence of a helical+toroidal magnetic field. Furthermore, the presence of low intrinsic polarization fractions indicate that the polarized emission and, hence, the helical+toroidal magnetic field, is present within the innermost jet.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"21 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702929","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":"Reconstructing orbits of galaxies in extreme regions (ROGER)","authors":"Hernán Muriel, David Pérez-Millán, Martín de los Rios, Andrea Biviano, Valeria Coenda, Héctor J. Martínez, Andrés N. Ruiz, Benedetta Vulcani, Selene Levis","doi":"10.1051/0004-6361/202453151","DOIUrl":"https://doi.org/10.1051/0004-6361/202453151","url":null,"abstract":"<i>Context.<i/> Clusters of galaxies have proven to be efficient systems in modifying various properties of galaxies, such as star formation or morphology. However, projection effects impose serious challenges in determining how, when, and to what extent galaxies are affected by the cluster environment.<i>Aims.<i/> Using innovative techniques to classify galaxies based on their history within the cluster, we aim to determine how galaxies of different classes are affected by the cluster environment.<i>Methods.<i/> We applied the ROGER code to select trajectories of galaxies in the phase space for 35 galaxy clusters from the OmegaWINGS survey. A new algorithm was applied to minimize contamination effects.<i>Results.<i/> We found that both morphological transformation and the quenching of star formation begin shortly after galaxies enter the cluster. Even though over the last 2 − 3 Gyr, galaxies entering clusters have undergone significant transformations in both their star formation and morphology these transformation processes are not complete, that is, they are not completely quenched and are not early type yet. Backsplash galaxies and recent infallers show a higher fraction of jellyfish galaxies compared to older cluster members, suggesting that the timescale of this phenomenon is typically less than 3 Gyr.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"183 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702990","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":"Helical flows along coronal loops following the launch of a coronal mass ejection","authors":"Mohamed Nedal, David M. Long, Catherine Cuddy, Lidia Van Driel-Gesztelyi, Peter T. Gallagher","doi":"10.1051/0004-6361/202453530","DOIUrl":"https://doi.org/10.1051/0004-6361/202453530","url":null,"abstract":"<i>Context.<i/> Solar flares and coronal mass ejections (CMEs) are manifestations of energy release in the solar atmosphere. They can be accompanied by dynamic mass motions and waves in the surrounding atmosphere.<i>Aims.<i/> We present observations of plasma moving in a helical trajectory along a set of coronal loops formed following the eruption of a CME on 2024 May 14. This helical motion was observed in extreme ultraviolet images from the Solar Dynamics Observatory (SDO) and provides new insights into plasma properties in a set of post-eruption coronal loops.<i>Methods.<i/> We utilized images from the SDO Atmospheric Imaging Assembly (AIA) instrument to track the helical motion of plasma and to characterize its speed, acceleration, and physical properties. Additionally, we explored the evolution of the plasma density and temperature along the helical structure using the differential emission measure technique.<i>Results.<i/> The helical structure was visible to AIA for approximately 22 minutes; it had a diameter of ∼22 Mm and a total trajectory of nearly 184 Mm. According to our analysis of the AIA observations, the speed of the plasma flow along this helical coronal loop ranged from 77 to 384 km s<sup>−1<sup/>, temperatures from 3.46 to 10.2 MK, densities from 4.3 × 10<sup>6<sup/> to 1.55 × 10<sup>7<sup/> cm<sup>−3<sup/>, and the magnetic field strength from 0.05 to 0.3 G.<i>Conclusions.<i/> Following the launch of the CME, we find clear evidence for impulsive heating and expansion of the plasma, which travelled along a helical trajectory along a set of post-eruption loops. These observations provide an insight into impulsive plasma flows along coronal loops and the topology of coronal loops.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"28 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702989","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}