Pub Date : 2024-10-01Epub Date: 2023-06-27DOI: 10.1177/17585732231185099
Nur Canbolat, Serkan Bayram, Yaşar Samet Gökçeoğlu, Okan Tezgel, Mehmet Kapicioğlu, Ali Erşen, Kerem Bilsel, Mehmet İlke Büget
Background: We aimed to evaluate the predictive determitants in patients with PHF who were treated with reverse shoulder arthroplasty (RSA) by evaluating the patient characteristics and comorbidities and extensive preoperative laboratory parameters.
Methods: With examining the records of elderly patients (over 65 years old) with PHF, who were admitted to our emergency department between 2009 and 2020. For evaluation of the survival, we performed Kaplan-Meirer statistical anaylses. A Cox algorithms (uni and multivariate) were applied to recognize factors (including clinical and laboratory parameters) which are associated with survival.
Results: Sixty-three females and 17 males were included with a mean of 73.5 ± 7.4 years of age. Nineteen (23.83%) patients had decreased after the surgery, with a mean survival of 47.5 ± 32.7 months. There were 61 (76.3%) surviving patients with a mean survival of 67.4 ± 35.4 months. Survival rates in the first 6 months (n: 2 patients), first year (n: 3 patients), and second year (n: 6 patients) after surgery were 97.5%, 96.3%, and 92.3%, respectively.
Conclusion: The age and preoperative hemoglobin level were independently related with poor survival in patients with PHF.
Level of evidence: Level III Retrospective Cohort, Prognosis Study.
{"title":"Predictive prognostic factors in patients with proximal humeral fracture treated with reverse shoulder arthroplasty.","authors":"Nur Canbolat, Serkan Bayram, Yaşar Samet Gökçeoğlu, Okan Tezgel, Mehmet Kapicioğlu, Ali Erşen, Kerem Bilsel, Mehmet İlke Büget","doi":"10.1177/17585732231185099","DOIUrl":"10.1177/17585732231185099","url":null,"abstract":"<p><strong>Background: </strong>We aimed to evaluate the predictive determitants in patients with PHF who were treated with reverse shoulder arthroplasty (RSA) by evaluating the patient characteristics and comorbidities and extensive preoperative laboratory parameters.</p><p><strong>Methods: </strong>With examining the records of elderly patients (over 65 years old) with PHF, who were admitted to our emergency department between 2009 and 2020. For evaluation of the survival, we performed Kaplan-Meirer statistical anaylses. A Cox algorithms (uni and multivariate) were applied to recognize factors (including clinical and laboratory parameters) which are associated with survival.</p><p><strong>Results: </strong>Sixty-three females and 17 males were included with a mean of 73.5 ± 7.4 years of age. Nineteen (23.83%) patients had decreased after the surgery, with a mean survival of 47.5 ± 32.7 months<b>.</b> There were 61 (76.3%) surviving patients with a mean survival of 67.4 ± 35.4 months. Survival rates in the first 6 months (n: 2 patients), first year (n: 3 patients), and second year (n: 6 patients) after surgery were 97.5%, 96.3%, and 92.3%, respectively.</p><p><strong>Conclusion: </strong>The age and preoperative hemoglobin level were independently related with poor survival in patients with PHF.</p><p><strong>Level of evidence: </strong>Level III Retrospective Cohort, Prognosis Study.</p>","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"339 1","pages":"518-526"},"PeriodicalIF":1.5,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11514117/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79740666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the past twenty years, there has been increasing evidence of the existence of sausage waves in the solar atmosphere. These observations make them useful tools in the context of atmospheric seismology. Here, we study sausage magnetohydrodynamic waves in a magnetic flux tube of non-zero plasma beta with a circular cross-section and a radially inhomogeneous plasma density. Solving numerically the equations of motion for an initial value problem, the spatio-temporal evolution of the velocity perturbations is obtained for different sets of parameters. We show that the ratio of the amplitudes of the longitudinal and radial perturbations is determined by the amount of plasma beta. Additionally, the longitudinal component of the velocity perturbation experiences phase-mixing within a layer surrounding the boundary of the flux tube with a rate depending on the amount of plasma beta. The results revealed that in the presence of a non-zero plasma beta, the flux tube exhibits oscillations in both the radial and longitudinal directions, characterized by a combination of two frequencies: one belonging to the slow continuum and the other to the Alfvén continuum. Also, the period of radial oscillation is obtained for different sets of parameters. The dependence of the period of the radial oscillation on the wavenumber confirms the results obtained in previous studies.
{"title":"On the sausage magnetohydrodynamic waves in magnetic flux tubes: finite plasma beta and phase mixing","authors":"Zanyar Ebrahimi","doi":"10.1093/mnras/stae2173","DOIUrl":"https://doi.org/10.1093/mnras/stae2173","url":null,"abstract":"Over the past twenty years, there has been increasing evidence of the existence of sausage waves in the solar atmosphere. These observations make them useful tools in the context of atmospheric seismology. Here, we study sausage magnetohydrodynamic waves in a magnetic flux tube of non-zero plasma beta with a circular cross-section and a radially inhomogeneous plasma density. Solving numerically the equations of motion for an initial value problem, the spatio-temporal evolution of the velocity perturbations is obtained for different sets of parameters. We show that the ratio of the amplitudes of the longitudinal and radial perturbations is determined by the amount of plasma beta. Additionally, the longitudinal component of the velocity perturbation experiences phase-mixing within a layer surrounding the boundary of the flux tube with a rate depending on the amount of plasma beta. The results revealed that in the presence of a non-zero plasma beta, the flux tube exhibits oscillations in both the radial and longitudinal directions, characterized by a combination of two frequencies: one belonging to the slow continuum and the other to the Alfvén continuum. Also, the period of radial oscillation is obtained for different sets of parameters. The dependence of the period of the radial oscillation on the wavenumber confirms the results obtained in previous studies.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"7 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
T M Gaudin, M J Coe, J A Kennea, I M Monageng, D A H Buckley, A Udalski, P A Evans
CXOU J005245.0-722844 is an X-ray source in the Small Magellanic Cloud (SMC) that has long been known as a Be/X-ray binary (BeXRB) star, containing an OBe main sequence star and a compact object. In this paper, we report on a new very fast X-ray outburst from CXOU J005245.0-722844. X-ray observations taken by Swift constrain the duration of the outburst to less than 16 days and find that the source reached super-Eddington X-ray luminosities during the initial phases of the eruption. The XRT spectrum of CXOU J005245.0-722844 during this outburst reveals a super-soft X-ray source, best fit by an absorbed thermal blackbody model. Optical and Ultraviolet follow-up observations from the Optical Gravitational Lensing Experiment (OGLE), Asteroid Terrestrial-impact Last Alert System (ATLAS), and Swift identify a brief ∼0.5 magnitude optical burst coincident with the X-ray outburst that lasted for less than 7 days. Optical photometry additionally identifies the orbital period of the system to be 17.55 days and identifies a shortening of the period to 17.14 days in the years leading up to the outburst. Optical spectroscopy from the Southern African Large Telescope (SALT) confirms that the optical companion is an early-type OBe star. We conclude from our observations that the compact object in this system is a white dwarf (WD), making this the seventh candidate Be/WD X-ray binary. The X-ray outburst is found to be the result of a very-fast, ultra-luminous nova similar to the outburst of MAXI J0158-744.
CXOU J005245.0-722844是小麦哲伦云（SMC）中的一个X射线源，长期以来一直被认为是一颗Be/X射线双星（BeXRB），其中包含一颗OBe主序星和一颗紧凑天体。在本文中，我们报告了来自 CXOU J005245.0-722844 的新的极快 X 射线爆发。由 Swift 拍摄的 X 射线观测数据将爆发持续时间限制在 16 天以内，并发现该星源在爆发初期达到了超爱丁顿 X 射线光度。这次爆发期间 CXOU J005245.0-722844 的 XRT 光谱显示出一个超软 X 射线源，与吸收热黑体模型的拟合效果最佳。来自光学引力透镜实验（OGLE）、小行星地面撞击最后警报系统（ATLAS）和雨燕的光学和紫外线跟踪观测发现，在X射线爆发的同时，还发生了一次持续时间不到7天的∼0.5等的短暂光学爆发。光学测光还确定了该系统的轨道周期为 17.55 天，并确定在爆发前的几年里，该周期缩短到了 17.14 天。南部非洲大型望远镜（SALT）的光学光谱分析证实，这颗光学伴星是一颗早期型 OBe 星。我们通过观测得出结论，这个系统中的紧凑天体是一颗白矮星（WD），这也是第七颗候选的Be/WD X射线双星。我们发现X射线爆发是一个极快的超亮新星爆发的结果，类似于MAXI J0158-744的爆发。
{"title":"CXOU J005245.0-722844: Discovery of a be star / white dwarf binary system in the SMC via a very fast, super-eddington X-ray outburst event","authors":"T M Gaudin, M J Coe, J A Kennea, I M Monageng, D A H Buckley, A Udalski, P A Evans","doi":"10.1093/mnras/stae2176","DOIUrl":"https://doi.org/10.1093/mnras/stae2176","url":null,"abstract":"CXOU J005245.0-722844 is an X-ray source in the Small Magellanic Cloud (SMC) that has long been known as a Be/X-ray binary (BeXRB) star, containing an OBe main sequence star and a compact object. In this paper, we report on a new very fast X-ray outburst from CXOU J005245.0-722844. X-ray observations taken by Swift constrain the duration of the outburst to less than 16 days and find that the source reached super-Eddington X-ray luminosities during the initial phases of the eruption. The XRT spectrum of CXOU J005245.0-722844 during this outburst reveals a super-soft X-ray source, best fit by an absorbed thermal blackbody model. Optical and Ultraviolet follow-up observations from the Optical Gravitational Lensing Experiment (OGLE), Asteroid Terrestrial-impact Last Alert System (ATLAS), and Swift identify a brief ∼0.5 magnitude optical burst coincident with the X-ray outburst that lasted for less than 7 days. Optical photometry additionally identifies the orbital period of the system to be 17.55 days and identifies a shortening of the period to 17.14 days in the years leading up to the outburst. Optical spectroscopy from the Southern African Large Telescope (SALT) confirms that the optical companion is an early-type OBe star. We conclude from our observations that the compact object in this system is a white dwarf (WD), making this the seventh candidate Be/WD X-ray binary. The X-ray outburst is found to be the result of a very-fast, ultra-luminous nova similar to the outburst of MAXI J0158-744.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"28 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Millisecond magnetars are widely suggested as the central engines powering hydrogen-poor superluminous supernovae (SLSNe). These magnetars primarily lose huge rotational energy through gravitational wave radiation (GWR) and magnetic dipole radiation (MDR), with MDR serving as an energy source for SLSNe. We study the evolution of the magnetar spin, magnetic inclination angle, and the resulting thermal radiative luminosity of the SLSNe, where the impacts of the nucleon-nucleon short-range correlation, the mass and initial spin of the magnetar, and the density-dependent symmetry energy of the dense nuclear matter on the evolution are discussed. The relativistic mean-field theory is employed to calculate the nuclear matter properties, and we particularly concentrate on the time- and space-dependent bulk viscosity which is crucial for the magnetic inclination angle evolution. It is found that the nucleon-nucleon short-range correlation weakens the damping of bulk viscosity of dense matter and therefore inhibits the growth of magnetic inclination angle, and it reduces the MDR (GWR) peak luminosity of a canonical magnetar by several times while it raises the peak thermal radiation luminosity of SLSNe by several times. For magnetars with nonrotating mass obviously lower than the $1.4 , rm M_odot$ with slow initial rotation, the magnetic inclination angle is more likely to evolve towards 0 degrees quickly, and these magnetars are not suitable as the central engine for SLSNe. Within the ‘family’ of FSUGarnet interaction, a stiffer symmetry energy gives a lower threshold of direct Urca process and hence gives a much larger bulk viscosity coefficient, and thus it promotes the growth of the magnetic inclination angle and the GWR for canonical stars but reduces the peak brightness of SLSNe significantly.
{"title":"Effects of nucleon-nucleon short-range correlation and symmetry energy on the evolution of newly born magnetars","authors":"C X Liu, T F Feng, J M Dong","doi":"10.1093/mnras/stae2170","DOIUrl":"https://doi.org/10.1093/mnras/stae2170","url":null,"abstract":"Millisecond magnetars are widely suggested as the central engines powering hydrogen-poor superluminous supernovae (SLSNe). These magnetars primarily lose huge rotational energy through gravitational wave radiation (GWR) and magnetic dipole radiation (MDR), with MDR serving as an energy source for SLSNe. We study the evolution of the magnetar spin, magnetic inclination angle, and the resulting thermal radiative luminosity of the SLSNe, where the impacts of the nucleon-nucleon short-range correlation, the mass and initial spin of the magnetar, and the density-dependent symmetry energy of the dense nuclear matter on the evolution are discussed. The relativistic mean-field theory is employed to calculate the nuclear matter properties, and we particularly concentrate on the time- and space-dependent bulk viscosity which is crucial for the magnetic inclination angle evolution. It is found that the nucleon-nucleon short-range correlation weakens the damping of bulk viscosity of dense matter and therefore inhibits the growth of magnetic inclination angle, and it reduces the MDR (GWR) peak luminosity of a canonical magnetar by several times while it raises the peak thermal radiation luminosity of SLSNe by several times. For magnetars with nonrotating mass obviously lower than the $1.4 , rm M_odot$ with slow initial rotation, the magnetic inclination angle is more likely to evolve towards 0 degrees quickly, and these magnetars are not suitable as the central engine for SLSNe. Within the ‘family’ of FSUGarnet interaction, a stiffer symmetry energy gives a lower threshold of direct Urca process and hence gives a much larger bulk viscosity coefficient, and thus it promotes the growth of the magnetic inclination angle and the GWR for canonical stars but reduces the peak brightness of SLSNe significantly.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"1 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Sergio Sánchez-Sanjuán, Jesús Hernández, Ángeles Pérez-Villegas, Carlos Román-Zúñiga, Luis Aguilar, Javier Ballesteros-Paredes, Andrea Bonilla-Barroso
In this work, we analysed young stellar clusters with spatial and kinematic coherence in the Orion star-forming complex. For this study, we selected a sample of pre-main sequence candidates using parallaxes, proper motions and positions on the colour-magnitude diagram. After applying a hierarchical clustering algorithm in the 5D parameter space provided by Gaia DR3, we divided the recovered clusters into two regimes: Big Structures and Small Structures, defined by the number of detected stars per cluster. In the first regime, we found 13 stellar groups distributed along the declination axis in the regions where there is a high density of stars. In the second regime, we recovered 34 clusters classified into two types: 14 as small groups completely independent from the larger structures, including four candidates of new clusters, and 12 classified as sub-structures embedded within five larger clusters. Additionally, radial velocity data from APOGEE-2 and GALAH DR3 was included to study the phase space in some regions of the Orion complex. From the Big Structure regime, we found evidence of a general expansion in the Orion OB1 association over a common centre, giving a clue about the dynamical effects the region is undergoing. Likewise, in the Small Structure regime, the projected kinematics shows the ballistic expansion in the λ Orionis association and the detection of likely events of clusters’ close encounters in the OB1 association.
{"title":"Kinematic study of the orion complex: Analysing the young stellar clusters from big and small structures","authors":"Sergio Sánchez-Sanjuán, Jesús Hernández, Ángeles Pérez-Villegas, Carlos Román-Zúñiga, Luis Aguilar, Javier Ballesteros-Paredes, Andrea Bonilla-Barroso","doi":"10.1093/mnras/stae2157","DOIUrl":"https://doi.org/10.1093/mnras/stae2157","url":null,"abstract":"In this work, we analysed young stellar clusters with spatial and kinematic coherence in the Orion star-forming complex. For this study, we selected a sample of pre-main sequence candidates using parallaxes, proper motions and positions on the colour-magnitude diagram. After applying a hierarchical clustering algorithm in the 5D parameter space provided by Gaia DR3, we divided the recovered clusters into two regimes: Big Structures and Small Structures, defined by the number of detected stars per cluster. In the first regime, we found 13 stellar groups distributed along the declination axis in the regions where there is a high density of stars. In the second regime, we recovered 34 clusters classified into two types: 14 as small groups completely independent from the larger structures, including four candidates of new clusters, and 12 classified as sub-structures embedded within five larger clusters. Additionally, radial velocity data from APOGEE-2 and GALAH DR3 was included to study the phase space in some regions of the Orion complex. From the Big Structure regime, we found evidence of a general expansion in the Orion OB1 association over a common centre, giving a clue about the dynamical effects the region is undergoing. Likewise, in the Small Structure regime, the projected kinematics shows the ballistic expansion in the λ Orionis association and the detection of likely events of clusters’ close encounters in the OB1 association.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"7 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Iuliana C Niţu, Michael J Keith, David J Champion, Ismaël Cognard, Gregory Desvignes, Lucas Guillemot, Yanjun Guo, Huanchen Hu, Jiwoong Jang, Jedrzej Jawor, Ramesh Karuppusamy, Evan F Keane, Michael Kramer, Kristen Lackeos, Kuo Liu, Robert A Main, Delphine Perrodin, Nataliya K Porayko, Golam M Shaifullah, Gilles Theureau
In this work, we investigated the presence of strictly periodic, as well as quasi-periodic signals, in the timing of the 25 millisecond pulsars from the EPTA DR2 dataset. This is especially interesting in the context of the recent hints of a gravitational wave background in these data, and the necessary further study of red-noise timing processes, which are known to behave quasi-periodically in some normal pulsars. We used Bayesian timing models developed through the run_enterprise pipeline: a strict periodicity was modelled as the influence of a planetary companion on the pulsar, while a quasi-periodicity was represented as a Fourier-domain Gaussian process. We found that neither model would clearly improve the timing models of the 25 millisecond pulsars in this dataset. This implies that noise and parameter estimates are unlikely to be biased by the presence of a (quasi-)periodicity in the timing data. Nevertheless, the results for PSRs J1744−1134 and J1012+5307 suggest that the standard noise models for these pulsars may not be sufficient. We also measure upper limits for the projected masses of planetary companions around each of the 25 pulsars. The data of PSR J1909−3744 yielded the best mass limits, such that we constrained the 95-percentile to ∼2 × 10−4 M⊕ (roughly the mass of the dwarf planet Ceres) for orbital periods between 5 d–17 yr. These are the best pulsar planet mass limits to date.
{"title":"Periodicity search in the timing of the 25 millisecond pulsars from the second data release of the European pulsar timing array","authors":"Iuliana C Niţu, Michael J Keith, David J Champion, Ismaël Cognard, Gregory Desvignes, Lucas Guillemot, Yanjun Guo, Huanchen Hu, Jiwoong Jang, Jedrzej Jawor, Ramesh Karuppusamy, Evan F Keane, Michael Kramer, Kristen Lackeos, Kuo Liu, Robert A Main, Delphine Perrodin, Nataliya K Porayko, Golam M Shaifullah, Gilles Theureau","doi":"10.1093/mnras/stae2162","DOIUrl":"https://doi.org/10.1093/mnras/stae2162","url":null,"abstract":"In this work, we investigated the presence of strictly periodic, as well as quasi-periodic signals, in the timing of the 25 millisecond pulsars from the EPTA DR2 dataset. This is especially interesting in the context of the recent hints of a gravitational wave background in these data, and the necessary further study of red-noise timing processes, which are known to behave quasi-periodically in some normal pulsars. We used Bayesian timing models developed through the run_enterprise pipeline: a strict periodicity was modelled as the influence of a planetary companion on the pulsar, while a quasi-periodicity was represented as a Fourier-domain Gaussian process. We found that neither model would clearly improve the timing models of the 25 millisecond pulsars in this dataset. This implies that noise and parameter estimates are unlikely to be biased by the presence of a (quasi-)periodicity in the timing data. Nevertheless, the results for PSRs J1744−1134 and J1012+5307 suggest that the standard noise models for these pulsars may not be sufficient. We also measure upper limits for the projected masses of planetary companions around each of the 25 pulsars. The data of PSR J1909−3744 yielded the best mass limits, such that we constrained the 95-percentile to ∼2 × 10−4 M⊕ (roughly the mass of the dwarf planet Ceres) for orbital periods between 5 d–17 yr. These are the best pulsar planet mass limits to date.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"24 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Alexander J Gordon, Annette M N Ferguson, Robert G Mann
Tidal features are a key observable prediction of the hierarchical model of galaxy formation and contain a wealth of information about the properties and history of a galaxy. Modern wide-field surveys such as LSST and Euclid will revolutionise the study of tidal features. However, the volume of data will prohibit visual inspection to identify features, thereby motivating a need to develop automated detection methods. This paper presents a visual classification of ∼2, 000 galaxies from the DECaLS survey into different tidal feature categories: arms, streams, shells, and diffuse. We trained a Convolutional Neural Network (CNN) to reproduce the assigned visual classifications using these labels. Evaluated on a testing set where galaxies with tidal features were outnumbered ∼1 : 10, our network performed very well and retrieved a median 98.7 ± 0.3, 99.1 ± 0.5, 97.0 ± 0.8, and $99.4^{+0.2}_{-0.6}$ per cent of the actual instances of arm, stream, shell, and diffuse features respectively for just 20percnt contamination. A modified version that identified galaxies with any feature against those without achieved scores of $0.981^{+0.001}_{-0.003}$, $0.834^{+0.014}_{-0.026}$, $0.974^{+0.008}_{-0.004}$, and $0.900^{+0.073}_{-0.015}$ for the accuracy, precision, recall, and F1 metrics, respectively. We used a Gradient-weighted Class Activation Mapping analysis to highlight important regions on images for a given classification to verify the network was classifying the galaxies correctly. This is the first demonstration of using CNNs to classify tidal features into sub-categories, and it will pave the way for the identification of different categories of tidal features in the vast samples of galaxies that forthcoming wide-field surveys will deliver.
{"title":"Uncovering Tidal Treasures: Automated Classification of faint tidal features in DECaLS Data","authors":"Alexander J Gordon, Annette M N Ferguson, Robert G Mann","doi":"10.1093/mnras/stae2169","DOIUrl":"https://doi.org/10.1093/mnras/stae2169","url":null,"abstract":"Tidal features are a key observable prediction of the hierarchical model of galaxy formation and contain a wealth of information about the properties and history of a galaxy. Modern wide-field surveys such as LSST and Euclid will revolutionise the study of tidal features. However, the volume of data will prohibit visual inspection to identify features, thereby motivating a need to develop automated detection methods. This paper presents a visual classification of ∼2, 000 galaxies from the DECaLS survey into different tidal feature categories: arms, streams, shells, and diffuse. We trained a Convolutional Neural Network (CNN) to reproduce the assigned visual classifications using these labels. Evaluated on a testing set where galaxies with tidal features were outnumbered ∼1 : 10, our network performed very well and retrieved a median 98.7 ± 0.3, 99.1 ± 0.5, 97.0 ± 0.8, and $99.4^{+0.2}_{-0.6}$ per cent of the actual instances of arm, stream, shell, and diffuse features respectively for just 20percnt contamination. A modified version that identified galaxies with any feature against those without achieved scores of $0.981^{+0.001}_{-0.003}$, $0.834^{+0.014}_{-0.026}$, $0.974^{+0.008}_{-0.004}$, and $0.900^{+0.073}_{-0.015}$ for the accuracy, precision, recall, and F1 metrics, respectively. We used a Gradient-weighted Class Activation Mapping analysis to highlight important regions on images for a given classification to verify the network was classifying the galaxies correctly. This is the first demonstration of using CNNs to classify tidal features into sub-categories, and it will pave the way for the identification of different categories of tidal features in the vast samples of galaxies that forthcoming wide-field surveys will deliver.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"12 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
W J Cooper, H R A Jones, R L Smart, S L Folkes, J A Caballero, F Marocco, M C Gálvez Ortiz, A J Burgasser, J D Kirkpatrick, L M Sarro, B Burningham, A Cabrera-Lavers, P E Tremblay, C Reylé, N Lodieu, Z H Zhang, N J Cook, J F Faherty, D García-Álvarez, D Montes, D J Pinfield, A S Rajpurohit, J Shi
As part of our comprehensive, ongoing characterisation of the low-mass end of the main sequence in the Solar neighbourhood, we used the OSIRIS instrument at the 10.4 m Gran Telescopio Canarias to acquire low- and mid-resolution (R≈300 and R≈2500) optical spectroscopy of 53 late-M and L ultracool dwarfs. Most of these objects are known but poorly investigated and lacking complete kinematics. We measured spectral indices, determined spectral types (six of which are new) and inferred effective temperature and surface gravity from BT-Settl synthetic spectra fits for all objects. We were able to measure radial velocities via line centre fitting and cross correlation for 46 objects, 29 of which lacked previous radial velocity measurements. Using these radial velocities in combination with the latest Gaia DR3 data, we also calculated Galactocentric space velocities. From their kinematics, we identified two candidates outside of the thin disc and four in young stellar kinematic groups. Two further ultracool dwarfs are apparently young field objects: 2MASSW J1246467+402715 (L4β), which has a potential, weak lithium absorption line, and G 196–3B (L3β), which was already known as young due to its well-studied primary companion.
作为对太阳邻近地区主序低质量末端进行全面、持续描述的一部分，我们利用 10.4 米加那利大望远镜上的 OSIRIS 仪器对 53 个晚 M 和晚 L 超冷矮星进行了中低分辨率（R≈300 和 R≈2500）光学光谱分析。这些天体中的大多数都是已知的，但研究较少，缺乏完整的运动学数据。我们测量了光谱指数，确定了光谱类型（其中六种是新的），并通过 BT-Settl 合成光谱拟合推断出所有天体的有效温度和表面重力。我们通过线中心拟合和交叉相关测量了 46 个天体的径向速度，其中 29 个天体以前没有测量过径向速度。利用这些径向速度和最新的盖亚 DR3 数据，我们还计算出了伽马中心空间速度。根据这些天体的运动学特征，我们确定了薄圆盘外的两个候选天体和年轻恒星运动组中的四个候选天体。另外两个超冷矮星显然是年轻的场天体：2MASSW J1246467+402715 (L4β)和 G 196-3B (L3β)。
{"title":"The Gaia Ultracool Dwarf Sample – IV. GTC/OSIRIS optical spectra of Gaia late-M and L dwarfs","authors":"W J Cooper, H R A Jones, R L Smart, S L Folkes, J A Caballero, F Marocco, M C Gálvez Ortiz, A J Burgasser, J D Kirkpatrick, L M Sarro, B Burningham, A Cabrera-Lavers, P E Tremblay, C Reylé, N Lodieu, Z H Zhang, N J Cook, J F Faherty, D García-Álvarez, D Montes, D J Pinfield, A S Rajpurohit, J Shi","doi":"10.1093/mnras/stae2102","DOIUrl":"https://doi.org/10.1093/mnras/stae2102","url":null,"abstract":"As part of our comprehensive, ongoing characterisation of the low-mass end of the main sequence in the Solar neighbourhood, we used the OSIRIS instrument at the 10.4 m Gran Telescopio Canarias to acquire low- and mid-resolution (R≈300 and R≈2500) optical spectroscopy of 53 late-M and L ultracool dwarfs. Most of these objects are known but poorly investigated and lacking complete kinematics. We measured spectral indices, determined spectral types (six of which are new) and inferred effective temperature and surface gravity from BT-Settl synthetic spectra fits for all objects. We were able to measure radial velocities via line centre fitting and cross correlation for 46 objects, 29 of which lacked previous radial velocity measurements. Using these radial velocities in combination with the latest Gaia DR3 data, we also calculated Galactocentric space velocities. From their kinematics, we identified two candidates outside of the thin disc and four in young stellar kinematic groups. Two further ultracool dwarfs are apparently young field objects: 2MASSW J1246467+402715 (L4β), which has a potential, weak lithium absorption line, and G 196–3B (L3β), which was already known as young due to its well-studied primary companion.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"32 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Xuejian Shen, Mark Vogelsberger, Josh Borrow, Yongao Hu, Evan Erickson, Rahul Kannan, Aaron Smith, Enrico Garaldi, Lars Hernquist, Takahiro Morishita, Sandro Tacchella, Oliver Zier, Guochao Sun, Anna-Christina Eilers, Hui Wang
We investigate galaxy sizes at redshift z ≳ 6 with the cosmological radiation-magneto-hydrodynamic simulation suite thesan(-hr). These simulations simultaneously capture reionization of the large-scale intergalactic medium and resolved galaxy properties. The intrinsic sizes ($r^{ast }_{1/2}$) of simulated galaxies increase moderately with stellar mass at $M_{ast } lesssim 10^{8}{, rm M_odot }$ and decrease fast at larger masses, resulting in a hump feature at $M_{ast }sim 10^{8}{, rm M_odot }$ that is insensitive to redshift. Low-mass galaxies are in the initial phase of size growth and are better described by a spherical shell model with feedback-driven outflows competing with the cold inflowing gas streams. In contrast, massive galaxies fit better with the disk formation model. They generally experience a phase of rapid compaction and gas depletion, likely driven by internal disk instability rather than external processes. We identify four compact quenched galaxies in the (95.5 cMpc)3 volume of thesan-1 at z ≃ 6 and their quenching follows reaching a characteristic stellar surface density akin to the massive compact galaxies at cosmic noon. Compared to observations, we find that the median UV effective radius ($R^{rm UV}_{rm eff}$) of simulated galaxies is at least three times larger than the observed ones at $M_{ast }lesssim 10^{9}{, rm M_odot }$ or MUV ≳ −20 at 6 ≲ z ≲ 10. The population of compact galaxies ($R^{rm UV}_{rm eff}lesssim 300, {rm pc}$) galaxies at $M_{ast }sim 10^{8}{, rm M_odot }$ is missing in our simulations. This inconsistency persists across many other cosmological simulations with different galaxy formation models and demonstrates the potential of using galaxy morphology to constrain physics of galaxy formation at high redshifts.
{"title":"The thesan project: galaxy sizes during the epoch of reionization","authors":"Xuejian Shen, Mark Vogelsberger, Josh Borrow, Yongao Hu, Evan Erickson, Rahul Kannan, Aaron Smith, Enrico Garaldi, Lars Hernquist, Takahiro Morishita, Sandro Tacchella, Oliver Zier, Guochao Sun, Anna-Christina Eilers, Hui Wang","doi":"10.1093/mnras/stae2156","DOIUrl":"https://doi.org/10.1093/mnras/stae2156","url":null,"abstract":"We investigate galaxy sizes at redshift z ≳ 6 with the cosmological radiation-magneto-hydrodynamic simulation suite thesan(-hr). These simulations simultaneously capture reionization of the large-scale intergalactic medium and resolved galaxy properties. The intrinsic sizes ($r^{ast }_{1/2}$) of simulated galaxies increase moderately with stellar mass at $M_{ast } lesssim 10^{8}{, rm M_odot }$ and decrease fast at larger masses, resulting in a hump feature at $M_{ast }sim 10^{8}{, rm M_odot }$ that is insensitive to redshift. Low-mass galaxies are in the initial phase of size growth and are better described by a spherical shell model with feedback-driven outflows competing with the cold inflowing gas streams. In contrast, massive galaxies fit better with the disk formation model. They generally experience a phase of rapid compaction and gas depletion, likely driven by internal disk instability rather than external processes. We identify four compact quenched galaxies in the (95.5 cMpc)3 volume of thesan-1 at z ≃ 6 and their quenching follows reaching a characteristic stellar surface density akin to the massive compact galaxies at cosmic noon. Compared to observations, we find that the median UV effective radius ($R^{rm UV}_{rm eff}$) of simulated galaxies is at least three times larger than the observed ones at $M_{ast }lesssim 10^{9}{, rm M_odot }$ or MUV ≳ −20 at 6 ≲ z ≲ 10. The population of compact galaxies ($R^{rm UV}_{rm eff}lesssim 300, {rm pc}$) galaxies at $M_{ast }sim 10^{8}{, rm M_odot }$ is missing in our simulations. This inconsistency persists across many other cosmological simulations with different galaxy formation models and demonstrates the potential of using galaxy morphology to constrain physics of galaxy formation at high redshifts.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"12 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
J Pelle, C R Argüelles, F L Vieyro, V Crespi, C Millauro, M F Mestre, O Reula, F Carrasco
Current images of the supermassive black hole (SMBH) candidates at the center of our Galaxy and M87 have opened an unprecedented era for studying strong gravity and the nature of relativistic sources. Very-long-baseline interferometry (VLBI) data show images consistent with a central SMBH within General Relativity (GR). However, it is essential to consider whether other well-motivated dark compact objects within GR could produce similar images. Recent studies have shown that dark matter (DM) halos modeled as self-gravitating systems of neutral fermions can harbor very dense fermionic cores at their centers, which can mimic the spacetime features of a black hole (BH). Such dense, horizonless DM cores can satisfy the observational constraints: they can be supermassive and compact and lack a hard surface. We investigate whether such cores can produce similar observational signatures to those of BHs when illuminated by an accretion disk. We compute images and spectra of the fermion cores with a general-relativistic ray tracing technique, assuming the radiation originates from standard α disks, which are self-consistently solved within the current DM framework. Our simulated images possess a central brightness depression surrounded by a ring-like feature, resembling what is expected in the BH scenario. For Milky Way-like halos, the central brightness depressions have diameters down to ∼35 μas as measured from a distance of approximately 8 kpc. Finally, we show that the DM cores do not possess photon rings, a key difference from the BH paradigm, which could help discriminate between the models.
{"title":"Imaging fermionic dark matter cores at the center of galaxies","authors":"J Pelle, C R Argüelles, F L Vieyro, V Crespi, C Millauro, M F Mestre, O Reula, F Carrasco","doi":"10.1093/mnras/stae2152","DOIUrl":"https://doi.org/10.1093/mnras/stae2152","url":null,"abstract":"Current images of the supermassive black hole (SMBH) candidates at the center of our Galaxy and M87 have opened an unprecedented era for studying strong gravity and the nature of relativistic sources. Very-long-baseline interferometry (VLBI) data show images consistent with a central SMBH within General Relativity (GR). However, it is essential to consider whether other well-motivated dark compact objects within GR could produce similar images. Recent studies have shown that dark matter (DM) halos modeled as self-gravitating systems of neutral fermions can harbor very dense fermionic cores at their centers, which can mimic the spacetime features of a black hole (BH). Such dense, horizonless DM cores can satisfy the observational constraints: they can be supermassive and compact and lack a hard surface. We investigate whether such cores can produce similar observational signatures to those of BHs when illuminated by an accretion disk. We compute images and spectra of the fermion cores with a general-relativistic ray tracing technique, assuming the radiation originates from standard α disks, which are self-consistently solved within the current DM framework. Our simulated images possess a central brightness depression surrounded by a ring-like feature, resembling what is expected in the BH scenario. For Milky Way-like halos, the central brightness depressions have diameters down to ∼35 μas as measured from a distance of approximately 8 kpc. Finally, we show that the DM cores do not possess photon rings, a key difference from the BH paradigm, which could help discriminate between the models.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"1 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
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