Astronomy & Astrophysics最新文献

{"title":"COSMOS brightest group galaxies III. Evolution of stellar ages","authors":"G. Gozaliasl, A. Finoguenov, A. Babul, O. Ilbert, M. Sargent, E. Vardoulaki, A. Faisst, Z. Liu, M. Shuntov, O. Cooper, K. Dolag, S. Toft, G. Magdis, G. Toni, B. Mobasher, R. Barr'e, W. Cui, D. Rennehan","doi":"10.1051/0004-6361/202449543","DOIUrl":"https://doi.org/10.1051/0004-6361/202449543","url":null,"abstract":"The unique characteristics of the brightest group galaxies (BGGs) serve as a link in the evolutionary continuum between galaxies such as the Milky Way and the more massive brightest cluster galaxies found in dense clusters. This research investigates the evolution of the stellar properties of BGGs over cosmic time ($z = 0.08-1.30$), extending the work from our prior studies. We analyzed the data of 246 BGGs selected from our X-ray galaxy group catalog within the COSMOS field, examining stellar age, mass, star-formation rate (SFR), specific SFR, and halo mass. We compared observations with the Millennium and Magneticum simulations. Additionally, we investigated whether stellar properties vary with the projected offset from the X-ray peak or the hosting halo center. We evaluated the accuracy of SED-derived stellar ages using a mock galaxy catalog, finding a mean absolute error of around 1 Gyr. Interestingly, the observed BGG age distributions exhibit a bias toward younger intermediate ages compared to both semi-analytical models and the Magneticum simulation. Our analysis of stellar age versus mass unveils intriguing trends with a positive slope, hinting at complex evolutionary pathways across redshifts. We observed a negative correlation between stellar age and SFR across all redshift ranges. We employed a cosmic time dependent main sequence framework to identify star forming BGGs and find that approximately 20 of BGGs in the local universe continue to exhibit characteristics typical of star forming galaxies, with this proportion increasing to 50 at $z=1.0$. Our findings support an inside-out formation scenario for BGGs, where older stellar populations reside near the X-ray peak and younger populations at larger offsets indicate ongoing star-formation. The observed distribution of stellar ages, particularly for lower-mass BGGs in the range of $10^ M_ deviates from the constant ages predicted by the models across all stellar mass ranges and redshifts. This discrepancy aligns with the current models' known limitations in accurately capturing galaxies' complex star-formation histories.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"40 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141919200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"COSMOS brightest group galaxies III. Evolution of stellar ages","authors":"G. Gozaliasl, A. Finoguenov, A. Babul, O. Ilbert, M. Sargent, E. Vardoulaki, A. Faisst, Z. Liu, M. Shuntov, O. Cooper, K. Dolag, S. Toft, G. Magdis, G. Toni, B. Mobasher, R. Barr'e, W. Cui, D. Rennehan","doi":"10.1051/0004-6361/202449543","DOIUrl":"https://doi.org/10.1051/0004-6361/202449543","url":null,"abstract":"The unique characteristics of the brightest group galaxies (BGGs) serve as a link in the evolutionary continuum between galaxies such as the Milky Way and the more massive brightest cluster galaxies found in dense clusters. This research investigates the evolution of the stellar properties of BGGs over cosmic time ($z = 0.08-1.30$), extending the work from our prior studies. We analyzed the data of 246 BGGs selected from our X-ray galaxy group catalog within the COSMOS field, examining stellar age, mass, star-formation rate (SFR), specific SFR, and halo mass. We compared observations with the Millennium and Magneticum simulations. Additionally, we investigated whether stellar properties vary with the projected offset from the X-ray peak or the hosting halo center. We evaluated the accuracy of SED-derived stellar ages using a mock galaxy catalog, finding a mean absolute error of around 1 Gyr. Interestingly, the observed BGG age distributions exhibit a bias toward younger intermediate ages compared to both semi-analytical models and the Magneticum simulation. Our analysis of stellar age versus mass unveils intriguing trends with a positive slope, hinting at complex evolutionary pathways across redshifts. We observed a negative correlation between stellar age and SFR across all redshift ranges. We employed a cosmic time dependent main sequence framework to identify star forming BGGs and find that approximately 20 of BGGs in the local universe continue to exhibit characteristics typical of star forming galaxies, with this proportion increasing to 50 at $z=1.0$. Our findings support an inside-out formation scenario for BGGs, where older stellar populations reside near the X-ray peak and younger populations at larger offsets indicate ongoing star-formation. The observed distribution of stellar ages, particularly for lower-mass BGGs in the range of $10^ M_ deviates from the constant ages predicted by the models across all stellar mass ranges and redshifts. This discrepancy aligns with the current models' known limitations in accurately capturing galaxies' complex star-formation histories.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"11 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141919665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"X-ray polarisation in AGN circumnuclear media. Polarisation framework and 2D torus models","authors":"Bert Vander Meulen, P. Camps, Djordje Savic, M. Baes, Giorgio Matt, M. Stalevski","doi":"10.1051/0004-6361/202450773","DOIUrl":"https://doi.org/10.1051/0004-6361/202450773","url":null,"abstract":"Cold gas and dust reprocess the central X-ray emission of active galactic nuclei (AGN), producing characteristic spectro-polarimetric features in the X-ray band. The recent launch of IXPE allows for observations of this X-ray polarisation signal, which encodes unique information on the parsec-scale circumnuclear medium of obscured AGN. However, the models for interpreting these polarimetric data are under-explored and do not reach the same level of sophistication as the corresponding spectral models. We aim at closing the gap between the spectral and spectro-polarimetric modelling of AGN circumnuclear media in the X-ray band by providing the tools for simulating X-ray polarisation in complex geometries of cold gas alongside X-ray spectra. We lay out the framework for X-ray polarisation in 3D radiative transfer simulations and provide an implementation to the 3D radiative transfer code SKIRT, focussing on (de)polarisation due to scattering and fluorescent re-emission. As an application, we explored the spectro-polarimetric properties of a 2D toroidal reprocessor of cold gas, modelling the circumnuclear medium of AGN. For the 2D torus model, we find a complex behaviour of the polarisation angle with photon energy, which we interpret as a balance between the reprocessed photon flux originating from different sky regions, with a direct link to the torus geometry. We calculated a large grid of AGN torus models and demonstrated how spatially resolved X-ray polarisation maps could form a useful tool for interpreting the geometrical information that is encoded in IXPE observations. With this work, we release high-resolution AGN torus templates that simultaneously describe X-ray spectra and spectro-polarimetry for observational data fitting with XSPEC. The SKIRT code can now model X-ray polarisation simultaneously with X-ray spectra and provide synthetic spectro-polarimetric observations for complex 3D circumnuclear media, with all features of the established SKIRT framework available.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"25 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141919104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"X-ray polarisation in AGN circumnuclear media. Polarisation framework and 2D torus models","authors":"Bert Vander Meulen, P. Camps, Djordje Savic, M. Baes, Giorgio Matt, M. Stalevski","doi":"10.1051/0004-6361/202450773","DOIUrl":"https://doi.org/10.1051/0004-6361/202450773","url":null,"abstract":"Cold gas and dust reprocess the central X-ray emission of active galactic nuclei (AGN), producing characteristic spectro-polarimetric features in the X-ray band. The recent launch of IXPE allows for observations of this X-ray polarisation signal, which encodes unique information on the parsec-scale circumnuclear medium of obscured AGN. However, the models for interpreting these polarimetric data are under-explored and do not reach the same level of sophistication as the corresponding spectral models. We aim at closing the gap between the spectral and spectro-polarimetric modelling of AGN circumnuclear media in the X-ray band by providing the tools for simulating X-ray polarisation in complex geometries of cold gas alongside X-ray spectra. We lay out the framework for X-ray polarisation in 3D radiative transfer simulations and provide an implementation to the 3D radiative transfer code SKIRT, focussing on (de)polarisation due to scattering and fluorescent re-emission. As an application, we explored the spectro-polarimetric properties of a 2D toroidal reprocessor of cold gas, modelling the circumnuclear medium of AGN. For the 2D torus model, we find a complex behaviour of the polarisation angle with photon energy, which we interpret as a balance between the reprocessed photon flux originating from different sky regions, with a direct link to the torus geometry. We calculated a large grid of AGN torus models and demonstrated how spatially resolved X-ray polarisation maps could form a useful tool for interpreting the geometrical information that is encoded in IXPE observations. With this work, we release high-resolution AGN torus templates that simultaneously describe X-ray spectra and spectro-polarimetry for observational data fitting with XSPEC. The SKIRT code can now model X-ray polarisation simultaneously with X-ray spectra and provide synthetic spectro-polarimetric observations for complex 3D circumnuclear media, with all features of the established SKIRT framework available.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"7 34","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141919746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asteroid pairs: Survey of the inner main belt","authors":"I. Kyrylenko, N. Y. Krugly, O. Golubov","doi":"10.1051/0004-6361/202450725","DOIUrl":"https://doi.org/10.1051/0004-6361/202450725","url":null,"abstract":"An asteroid pair forms when an asteroid splits into two unbound fragments because of collision, rotational fission, or binary system decay. The two components of the asteroid pair share similar physical properties and their orbits converge when integrated into the past. Currently, 268 asteroid pairs are known, and new pairs are discovered alongside the continuous discovery of new asteroids. We conducted a survey in the inner asteroid belt to find new asteroid pairs, estimated their age, and classified their physical properties. As presently no M-type asteroid pairs are known, we also conducted a specialized survey of them. We preselected asteroid pair candidates based on their distances in the five-dimensional space of osculating orbital elements. We created multiple clones within the uncertainties of their orbital elements and conducted their backtrack integration into the past. We searched for convergence of their clones at close spatial points with small relative velocities, the distribution of which determines the pair formation age. We find 40 new asteroid pairs, thus increasing the total number of known pairs by 15. One of the newly discovered pairs, 469759 - 2016 QZ123, with an age of $2.6_ $ kyr is now the third-youngest known asteroid pair. We studied the influence of the mutual gravitation of pair components on the process of their evolution and successfully observed the gravitational catching of the two pair members in the past. As a byproduct of pair search, we find eight asteroids connected in a cluster with an age of $76_ $ kyr that belongs to the Phocaea family and incorporates one previously known asteroid pair. We confirm the convergence of ten asteroid pairs discovered in our previous research and improve their age estimates. We observed a deficiency of M-type asteroid pairs, and therefore conducted a dedicated search for M-type pairs, but found none.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"10 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the HD 95086 system at mid-infrared wavelengths with JWST/MIRI","authors":"M. Mâlin, A. Boccaletti, C. Perrot, P. Baudoz, Daniel Rouan, P. Lagage, Rens Waters, M. Gudel, Thomas K. Henning, B. Vandenbussche, O. Absil, D. Barrado, C. Cossou, L. Decin, M. Adrian Glauser, J. Pye, Göran Olofsson, Alistair Glasse, F. Lahuis, P. Patapis, P. Royer, S. Scheithauer, N. Whiteford, E. Serabyn, É. Choquet, Luis Colina, G. Ostlin, T. Ray","doi":"10.1051/0004-6361/202450470","DOIUrl":"https://doi.org/10.1051/0004-6361/202450470","url":null,"abstract":"Mid-infrared imaging of exoplanets and disks is now possible with the coronographs of the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST).\u0000 This wavelength range unveils new features of young directly imaged systems and allows us to obtain new constraints for characterizing the atmosphere of young giant exoplanets and associated disks. These observations aim to characterize the atmosphere of the planet HD,95086,b by adding mid-infrared information so that the various hypotheses about its atmospheric parameters values can be unraveled. Improved images of cirsumstellar disks are provided. We present the MIRI coronagraphic imaging of the system HD,95086 obtained with the F1065C, F1140, and F2300C filters at central wavelengths of 10.575,mu m, 11.3,mu m, and 23,mu m, respectively. We explored the method for subtracting the stellar diffraction pattern in the particular case when bright dust emitting at short separation is present. Furthermore, we compared different methods for extracting the photometry of the planet. Using the atmospheric models Exo-REM and ATMO we measured the atmospheric parameters of HD,95086,b. The planet HD,95086,b is detected at the two shortest MIRI wavelengths F1065C and F1140C. The contribution from the inner disk of the system is also detected. It is similar to that in the HR,8799 system. The outer colder belt is imaged at 23 mu m. Background objects are observed in all filters. The mid-infrared photometry provides better constraints on the atmospheric parameters. We evaluate a temperature of 850 -- 1020,K, consistent with one previous hypothesis that only used near-infrared data. The radius measurement of 1.0 -- 1.13 Jup $ is better aligned with evolutionary models, but still smaller than predicted.\u0000 These observations allow us to refute the hypothesis of a warm circumplanetary disk. HD,95086 is one of the first exoplanetary systems to be revealed at mid-infrared wavelengths. This highlights the interests and challenges of observations at these wavelengths.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"42 31","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of the RR Lyrae period determination in the Pan-STARRS PS1 3pi survey with K2","authors":"A. Forró, László Molnár, E. Plachy, Á. Juhász, R. Szabó","doi":"10.1051/0004-6361/202450701","DOIUrl":"https://doi.org/10.1051/0004-6361/202450701","url":null,"abstract":"The Pan-STARRS 3pi survey has detected hundreds of thousands of variable stars thanks to its coverage and 4-year time span, even though the sampling of the light curves is relatively sparse. These light curves contain only 10-15 detections in each of the five filters (g,r,i,z,y). During the K2 mission, the Kepler space telescope observed along the ecliptic plane with a high sampling frequency, although only for about 80 days in each of its campaigns. Crossmatching and investigating the RR Lyrae stars observed by both K2 and Pan-STARRS can serve as a valuable tool to validate the classification and period determination of the ground-based survey. We used the Sesar catalogue of RR Lyrae stars detected by Pan-STARRS. After determining the overlap between the stars observed by both Pan-STARRS and K2, we also considered the Gaia DR3 SOS RR Lyrae catalogue \u0000 data for the list of these stars wherever it was available. The frequencies of the light variations were calculated by applying the Lomb-Scargle periodogram method on the K2 light curves that were prepared with autoEAP photometry. The calculated frequencies of the stars then were compared with those given in the Sesar catalogue and the Gaia DR3 RR Lyrae catalogue. We found that for the majority of the stars, the classification (95.6 ) and the frequency determination (90.1 ) of the Pan-STARRS RR Lyrae stars were consistent within 0.03 $d^ $ with those that we derived from the K2 autoEAP light curves. For a significant subset of the sample, 7.4 , however, an offset of 1 or 2 $d^ $ was found in the frequencies. These are the result of the sampling of the detections, because Pan-STARRS observations are affected by diurnal cycles, whereas Kepler carried out measurements quasi-continuously. We found that RRc subtypes are significantly more affected (25.3) than RRab subtypes (3.7), which is most likely caused by RRc stars having less sharp light curve features. Validation via space-based data will be important for future ground-based surveys, as well.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"5 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141925443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suppression of giant planet formation around low-mass stars in clustered environments","authors":"Shuo Huang, S. P. Portegies Zwart, M. Wilhelm","doi":"10.1051/0004-6361/202451051","DOIUrl":"https://doi.org/10.1051/0004-6361/202451051","url":null,"abstract":"Current exoplanet formation studies tend to overlook the birth environment of stars in clustered environments. However, the effects of this environment on the planet formation process are important, especially in the earliest stage. We investigate the differences in planet populations forming in star-cluster environments through pebble accretion and compare these results with planet formation around isolated stars. We strive to provide potential signatures of the young planetary systems to guide future observations. We present a new planet population synthesis code designed for clustered environments. This planet formation model is based on pebble accretion and includes migration in the circumstellar disk. The disk's gas and dust have been evolved via 1D simulations, while considering the effects of photo-evaporation of the nearby stars. Planetary systems in a clustered environment are different than those born in isolation; the environmental effects are important for a wide range of observable parameters and the eventual architecture of the planetary systems. Planetary systems born in a clustered environment lack cold Jupiters, as compared to isolated planetary systems. This effect is more pronounced for low-mass stars (lesssim 0.2 $M_ On the other hand, planetary systems born in clusters show an excess of cold Neptune around these low-mass stars. In future observations, finding an excess of cold Neptunes and a lack of cold Jupiters could be used to constrain the birth environments of these planetary systems. Exploring the dependence of cold Jupiter's intrinsic occurrence rate on stellar mass offers insights into the birth environment of their proto-embryos.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"36 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protostellar Outflows at the EarliesT Stages (POETS)\u0000 V. The launching mechanism of protostellar winds via water masers","authors":"L. Moscadelli, A. Oliva, A. Sanna, G. Surcis, O. Bayandina","doi":"10.1051/0004-6361/202451244","DOIUrl":"https://doi.org/10.1051/0004-6361/202451244","url":null,"abstract":"Understanding the launching mechanism of winds and jets remains one of the fundamental challenges in astrophysics. The Protostellar Outflows at the EarliesT Stages (POETS) survey has recently mapped the 3D velocity field of the protostellar winds in a sample (37) of luminous young stellar objects (YSOs) at scales of 10--100 au via very long baseline interferometry (VLBI) observations of the 22 GHz water masers. In most of the targets, the distribution of the 3D maser velocities can be explained in terms of a magnetohydrodynamic (MHD) disk wind (DW). Our goal is to assess the launching mechanism of the protostellar wind in the YSO the most promising MHD DW candidate from the POETS survey. We have performed multi-epoch Very Long Baseline Array (VLBA) observations of the 22 GHz water masers in to determine the 3D velocities of the gas flowing along several wind streamlines previously identified at a linear resolution of sim 1 au. Near the YSO at small separations along ($xl 150$ au) and across ($R 40$ au) the jet axis, water masers trace three individual DW streamlines. By exploiting the 3D kinematic information of the masers, we determined the launch radii of these streamlines with an accuracy of sim 1 au, and they lie in the range of 10--50 au. At increasingly greater distances along the jet (110 au $ xl 220$ au), the outflowing gas speeds up while it collimates close to the jet axis. Magneto-centrifugal launching in a radially extended MHD DW appears to be the only viable process to explain the fast (up to 60 and collimated (down to 10 velocities of the wind in correspondence with launch radii ranging between 10 and 50 au. At larger separations from the jet axis ($R 100$ au), the water masers trace a slow (le 20 radially expanding arched shock-front with kinematics inconsistent with magneto-centrifugal launching. Our resistive-magnetohydrodynamical simulations indicate that this shock-front could be driven by magnetic pressure. The results obtained in demonstrate that VLBI observations of the 22 GHz water masers can reliably determine the launching mechanism of protostellar winds.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"40 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-temporal-resolution optical spectroscopic observations of the transitional millisecond pulsar PSR J1023+0038","authors":"M. Messa, P. D'Avanzo, F. Coti Zelati, M. C. Baglio, S. Campana","doi":"10.1051/0004-6361/202449466","DOIUrl":"https://doi.org/10.1051/0004-6361/202449466","url":null,"abstract":"Transitional millisecond pulsars (tMSPs) represent a dynamic category of celestial sources that establish a crucial connection between low-mass X-ray binaries and millisecond radio pulsars. These systems exhibit transitions from rotation-powered states to accretion-powered ones and vice versa, highlighting the tight evolutionary link expected by the so-called recycling scenario. In their active phase, these sources manifest two distinct emission modes named high and low, occasionally punctuated by sporadic flares. Here, we present high-time-resolution spectroscopic observations of the binary tMSP J1023+0038, in the sub-luminous disc state. This is the first short-timescale (sim 1 min) optical spectroscopic campaign ever conducted on a tMSP. The campaign was carried out over the night of June 10, 2021 using the Gran Telescopio Canarias. The optical continuum shows erratic variability, without clear evidence of high and low modes or of orbital modulation. Besides, the analysis of these high-temporal-cadence spectroscopic observations reveals, for the first time, evidence for a significant (up to a factor of $ 2$) variability in the emission line properties (equivalent width and full width half maximum) over a timescale of minutes. Intriguingly, the variability episodes observed in the optical continuum and in the emission line properties seem uncorrelated, making their origin unclear.","PeriodicalId":8585,"journal":{"name":"Astronomy & Astrophysics","volume":"29 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}