The Astronomy and Astrophysics Review最新文献

{"title":"Simulating the Galactic multi-messenger emissions with HERMES","authors":"A. Dundović, Carmelo Evoli, D. Gaggero, D. Grasso","doi":"10.1051/0004-6361/202140801","DOIUrl":"https://doi.org/10.1051/0004-6361/202140801","url":null,"abstract":"The study of non-thermal processes such as synchrotron emission, inverse Compton scattering, bremsstrahlung and pion production is crucial to understand the properties of the Galactic cosmic-ray population, to shed light on their origin and confinement mechanisms, and to assess the significance of exotic signals possibly associated to new physics. We present a public code called HERMES aimed at generating sky maps associated to a variety of multi-messenger and multi-wavelength radiative processes, spanning from the radio domain all the way up to high-energy gamma-ray and neutrino production. We describe the physical processes under consideration, the code concept and structure, and the user interface, with particular focus on the python-based interactive mode. We especially present the modular and flexible design that allows to easily further extend the numerical package according to the user's needs. In order to demonstrate the capabilities of the code, we describe in detail a comprehensive set of sky maps and spectra associated to all physical processes included in the code. We comment in particular on the radio, gamma-ray, and neutrino maps, and mention the possibility to study signals stemming from dark matter annihilation. HERMES can be successfully applied to constrain the properties of the Galactic cosmic-ray population, improve our understanding of the diffuse Galactic radio, gamma--ray, and neutrino emission, and search for signals associated to particle dark matter annihilation or decay.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"3 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81584410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Weighing stars from birth to death: mass determination methods across the HRD","authors":"Aldo Serenelli,&nbsp;Achim Weiss,&nbsp;Conny Aerts,&nbsp;George C. Angelou,&nbsp;David Baroch,&nbsp;Nate Bastian,&nbsp;Paul G. Beck,&nbsp;Maria Bergemann,&nbsp;Joachim M. Bestenlehner,&nbsp;Ian Czekala,&nbsp;Nancy Elias-Rosa,&nbsp;Ana Escorza,&nbsp;Vincent Van Eylen,&nbsp;Diane K. Feuillet,&nbsp;Davide Gandolfi,&nbsp;Mark Gieles,&nbsp;Léo Girardi,&nbsp;Yveline Lebreton,&nbsp;Nicolas Lodieu,&nbsp;Marie Martig,&nbsp;Marcelo M. Miller Bertolami,&nbsp;Joey S. G. Mombarg,&nbsp;Juan Carlos Morales,&nbsp;Andrés Moya,&nbsp;Benard Nsamba,&nbsp;Krešimir Pavlovski,&nbsp;May G. Pedersen,&nbsp;Ignasi Ribas,&nbsp;Fabian R. N. Schneider,&nbsp;Victor Silva Aguirre,&nbsp;Keivan G. Stassun,&nbsp;Eline Tolstoy,&nbsp;Pier-Emmanuel Tremblay,&nbsp;Konstanze Zwintz","doi":"10.1007/s00159-021-00132-9","DOIUrl":"https://doi.org/10.1007/s00159-021-00132-9","url":null,"abstract":"<p>The mass of a star is the most fundamental parameter for its structure, evolution, and final fate. It is particularly important for any kind of stellar archaeology and characterization of exoplanets. There exist a variety of methods in astronomy to estimate or determine it. In this review we present a significant number of such methods, beginning with the most direct and model-independent approach using detached eclipsing binaries. We then move to more indirect and model-dependent methods, such as the quite commonly used isochrone or stellar track fitting. The arrival of quantitative asteroseismology has opened a completely new approach to determine stellar masses and to complement and improve the accuracy of other methods. We include methods for different evolutionary stages, from the pre-main sequence to evolved (super)giants and final remnants. For all methods uncertainties and restrictions will be discussed. We provide lists of altogether more than 200 benchmark stars with relative mass accuracies between <span>([0.3,2]%)</span> for the covered mass range of <span>(Min [0.1,16],M_odot)</span>, <span>(75%)</span> of which are stars burning hydrogen in their core and the other <span>(25%)</span> covering all other evolved stages. We close with a recommendation how to combine various methods to arrive at a “mass-ladder” for stars.</p>","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"29 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s00159-021-00132-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5015899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 a multi-spacecraft coronal mass ejection encounter with EUHFORIA","authors":"E. Asvestari, J. Pomoell, E. Kilpua, S. Good, T. Chatzistergos, M. Temmer, E. Palmerio, S. Poedts, J. Magdalenić","doi":"10.1051/0004-6361/202140315","DOIUrl":"https://doi.org/10.1051/0004-6361/202140315","url":null,"abstract":"Coronal mass ejections (CMEs) are a manifestation of the Sun's eruptive nature. They can have a great impact on Earth, but also on human activity in space and on the ground. Therefore, modelling their evolution as they propagate through interplanetary space is essential. EUropean Heliospheric FORecasting Information Asset (EUHFORIA) is a data-driven, physics-based model, tracing the evolution of CMEs through background solar wind conditions. It employs a spheromak flux rope, which provides it with the advantage of reconstructing the internal magnetic field configuration of CMEs. This is something that is not included in the simpler cone CME model used so far for space weather forecasting. This work aims at assessing the spheromak CME model included in EUHFORIA. We employed the spheromak CME model to reconstruct a well observed CME and compare model output to in situ observations. We focus on an eruption from 6 January 2013 encountered by two radially aligned spacecraft, Venus Express and STEREO-A. We first analysed the observed properties of the source of this CME eruption and we extracted the CME properties as it lifted off from the Sun. Using this information, we set up EUHFORIA runs to model the event. The model predicts arrival times from half to a full day ahead of the in situ observed ones, but within errors established from similar studies. In the modelling domain, the CME appears to be propagating primarily southward, which is in accordance with white-light images of the CME eruption close to the Sun. In order to get the observed magnetic field topology, we aimed at selecting a spheromak rotation angle for which the axis of symmetry of the spheromak is perpendicular to the direction of the polarity inversion line (PIL). The modelled magnetic field profiles, their amplitude, arrival times, and sheath region length are all affected by the choice of radius of the modelled spheromak.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"64 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80340520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"PACT. II. Pressure profiles of galaxy clusters using Planck and ACT","authors":"E. Pointecouteau, I. Santiago-Bautista, M. Douspis, N. Aghanim, D. Crichton, J. Diego, G. Hurier, J. Macías-Pérez, T. Marriage, M. Remazeilles, C. Caretta, H. Bravo-Alfaro","doi":"10.1051/0004-6361/202040213","DOIUrl":"https://doi.org/10.1051/0004-6361/202040213","url":null,"abstract":"The pressure of hot gas in groups and clusters of galaxies is a key physical quantity, which is directly linked to the total mass of the halo and several other thermodynamical properties. In the wake of previous observational works on the hot gas pressure distribution in massive halos, we have investigated a sample of 31 clusters detected in both the Planck and Atacama Cosmology Telescope (ACT), MBAC surveys. We made use of an optimised Sunyaev-Zeldovich (SZ) map reconstructed from the two data sets and tailored for the detection of the SZ e ff ect, taking advantage of both Planck coverage of large scales and the ACT higher spatial resolution. Our average pressure profile covers a radial range going from 0 . 04 × R 500 in the central parts to 2 . 5 × R 500 in the outskirts. In this way, it improves upon previous pressure-profile reconstruction based on SZ measurements. It is compatible, as well as competitive, with constraints derived from joint X-ray and SZ analysis. This work demonstrates the possibilities o ff ered by large sky surveys of the SZ e ff ect with multiple experiments with di ff erent spatial resolutions and spectral coverages, such as ACT and Planck .","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"295 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89067185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Wide companions to M and L subdwarfs with Gaia and the Virtual Observatory","authors":"J. Gonz'alez-Payo, M. Cort'es-Contreras, N. Lodieu, E. Solano, Z. Zhang, M. G'alvez-Ortiz","doi":"10.1051/0004-6361/202140493","DOIUrl":"https://doi.org/10.1051/0004-6361/202140493","url":null,"abstract":"Aims. The aim of the project is to identify wide common proper motion companions to a sample of spectroscopically confirmed M and L metal-poor dwarfs (also known as subdwarfs) to investigate the impact of metallicity on the binary fraction of low-mass metal-poor binaries and to improve the determination of their metallicity from the higher-mass binary. Methods. We made use of Virtual Observatory tools and large-scale public surveys to look in Gaia for common proper motion companions to a well-defined sample of ultracool subdwarfs with spectral types later than M5 and metallicities below or equal to −0.5 dex. We collected low-resolution optical spectroscopy for our best system, which is a binary composed of one sdM1.5 subdwarf and one sdM5.5 subdwarf located at ∼1 360 au, and for another two likely systems separated by more than 115 000 au. Results. We confirm one wide companion to an M subdwarf, and infer a multiplicity for M subdwarfs (sdMs) of 1.0+2.0 −1.0% for projected physical separations of up to 743 000 au. We also find four M–L systems, three of which are new detections. No colder companion was identified in any of the 219 M and L subdwarfs of the sample, mainly because of limitations on the detection of faint sources with Gaia. We infer a frequency of wide systems for sdM5–9.5 of 0.60+1.17 −0.60% for projected physical separations larger than 1 360 au (up to 142 400 au). This study shows a multiplicity rate of 1.0+2.0 −1.0% in sdMs, and 1.9 +3.7 −1.9% in extreme M subdwarfs (esdMs). We did not find any companion for the ultra M subdwarfs (usdMs) of our sample, establishing an upper limit of 5.3% on binarity for these objects.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"1 1","pages":"143"},"PeriodicalIF":25.8,"publicationDate":"2021-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89159673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 ionized heart of a molecular disk","authors":"L. Moscadelli, R. Cesaroni, M. Beltr'an, V. Rivilla","doi":"10.1051/0004-6361/202140829","DOIUrl":"https://doi.org/10.1051/0004-6361/202140829","url":null,"abstract":"The study of hyper-compact (HC) or ultra-compact (UC) HII regions is\u0000fundamental to understanding the process of massive (> 8 M_sun) star formation.\u0000We employed Atacama Large Millimeter/submillimeter Array (ALMA) 1.4 mm Cycle 6\u0000observations to investigate at high angular resolution (~0.050\", corresponding\u0000to 330 au) the HC HII region inside molecular core A1 of the high-mass\u0000star-forming cluster G24.78+0.08. We used the H30alpha emission and different\u0000molecular lines of CH3CN and 13CH3CN to study the kinematics of the ionized and\u0000molecular gas, respectively. At the center of the HC HII region, at radii <~500\u0000au, we observe two mutually perpendicular velocity gradients, which are\u0000directed along the axes at PA = 39 deg and PA = 133 deg, respectively. The\u0000velocity gradient directed along the axis at PA = 39 deg has an amplitude of 22\u0000km/s mpc^(-1), which is much larger than the other's, 3 km/s mpc^(-1). We\u0000interpret these velocity gradients as rotation around, and expansion along, the\u0000axis at PA = 39 deg. We propose a scenario where the H30alpha line traces the\u0000ionized heart of a disk-jet system that drives the formation of the massive\u0000star (~20 M_sun) responsible for the HC HII region. Such a scenario is also\u0000supported by the position-velocity plots of the CH3CN and 13CH3CN lines along\u0000the axis at PA = 133 deg, which are consistent with Keplerian rotation around a\u000020 M_sun star. Toward the HC HII region in G24.78+0.08, the coexistence of mass\u0000infall (at radii of ~5000 au), an outer molecular disk (from ~500\u0000au), and an inner ionized disk (<~500 au) indicates that the massive ionizing\u0000star is still actively accreting from its parental molecular core. To our\u0000knowledge, this is the first example of a molecular disk around a high-mass\u0000forming star that, while becoming internally ionized after the onset of the HII\u0000region, continues to accrete mass onto the ionizing star.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"24 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83443778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Probing core overshooting using subgiant asteroseismology: The case of KIC10273246 (Corrigendum)","authors":"A. Noll, S. Deheuvels, J. Ballot","doi":"10.1051/0004-6361/202040055E","DOIUrl":"https://doi.org/10.1051/0004-6361/202040055E","url":null,"abstract":"","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"283 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76836948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 peculiar nebula Simeis 57","authors":"L. Oudshoorn, F. Israel, J. Brinchmann, M. Kloppenburg, A. Brown, J. Bally, T. Gull, P. Boyd","doi":"10.1051/0004-6361/202039372","DOIUrl":"https://doi.org/10.1051/0004-6361/202039372","url":null,"abstract":"Simeis 57 (HS 191) is an optically bright nebula in the Cygnus X region with a peculiar appearance that suggests an outflow from a rotating source. Newly obtained observations and archival data reveal Simeis 57 as a low-density ($n_{e},sim,100$ cm$^{-3}$) nebula with an east-to-west excitation gradient. The extinction of the nebula is $A_{V},leq$ 2 mag. The nebula is recognizable but not prominent in mid- and far-infrared images. In its direction, half a dozen small CO clouds have been identified at $V_{LSR}$ = + 5 km s$^{-1}$. One of these coincides with both the optical nebula and a second CO cloud at the nebular velocity $V_{LSR},approx$ -10 km $^{-1}$. No luminous stars are embedded in these molecular clouds, nor are any obscured by them and no sufficiently luminous stars are found in the immediate vicinity of the nebula. Instead, all available data points to the evolved star HD 193793 = WR 140 (an O4-5 supergiant and WC7 Wolf-Rayet binary) as the source of excitation, notwithstanding its large separation of $50'$, about 25 pc at the stellar distance of 1.7 kpc. Simeis 57 appears to be a part of a larger structure surrounding the HI void centered on HD 193793.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"1 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83708256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"What happened before?","authors":"Per-Gunnar Valegård, L. Waters, C. Dominik","doi":"10.1051/0004-6361/202039802","DOIUrl":"https://doi.org/10.1051/0004-6361/202039802","url":null,"abstract":"We seek to find the precursors of the Herbig Ae/Be stars in the solar vicinity within 500 pc from the Sun. We do this by creating an optically selected sample of intermediate mass T-Tauri stars (IMTT stars) here defined as stars of masses $1.5 M_{odot}leq M_* leq 5 M_{odot}$ and spectral type between F and K3, from literature. We use literature optical photometry (0.4-1.25$mu$m) and distances determined from Gaia DR2 parallax measurements together with Kurucz stellar model spectra to place the stars in a HR-diagram. With Siess evolutionary tracks we identify intermediate mass T-Tauri stars from literature and derive masses and ages. We use Spitzer spectra to classify the disks around the stars into Meeus Group I and Group II disks based on their [F$_{30}$/F$_{13.5}$] spectral index. We also examine the 10$mu$m silicate dust grain emission and identify emission from Polycyclic Aromatic Hydrocarbons (PAH). From this we build a qualitative picture of the disks around the intermediate mass T-Tauri stars and compare this with available spatially resolved images at infrared and at sub-millimeter wavelengths to confirm our classification. We find 49 intermediate mass T-Tauri stars with infrared excess. The identified disks are similar to the older Herbig Ae/Be stars in disk geometries and silicate dust grain population. Spatially resolved images at infra-red and sub-mm wavelengths suggest gaps and spirals are also present around the younger precursors to the Herbig Ae/Be stars. Comparing the timescale of stellar evolution towards the main sequence and current models of protoplanetary disk evolution the similarity between Herbig Ae/Be stars and the intermediate mass T-Tauri stars points towards an evolution of Group I and Group II disks that are disconnected, and that they represent two different evolutionary paths.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"68 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80685778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Stability of solar atmospheric structures harboring standing slow waves","authors":"M. Geeraerts, T. Van Doorsselaere","doi":"10.1051/0004-6361/202140534","DOIUrl":"https://doi.org/10.1051/0004-6361/202140534","url":null,"abstract":"Context. In the context of the solar coronal heating problem, one possible explanation for the high coronal temperature is the release of energy by magnetohydrodynamic (MHD) waves. The energy transfer is believed to be possible, among others, by the development of the Kelvin-Helmholtz instability (KHI) in coronal loops. Aims. Our aim is to determine if standing slow waves in solar atmospheric structures such as coronal loops, and also prominence threads, sunspots, and pores, can trigger the KHI due to the oscillating shear flow at the structure’s boundary. Methods. We used linearized nonstationary MHD to work out an analytical model in a cartesian reference frame. The model describes a compressible plasma near a discontinuous interface separating two regions of homogeneous plasma, each harboring an oscillating velocity field with a constant amplitude which is parallel to the background magnetic field and aligned with the interface. The obtained analytical results were then used to determine the stability of said interface, both in coronal and photospheric conditions. Results. We find that the stability of the interface is determined by a Mathieu equation. In function of the parameters of this equation, the interface can either be stable or unstable. For coronal as well as photospheric conditions, we find that the interface is stable with respect to the KHI. Theoretically, it can, however, be unstable with respect to a parametric resonance instability, although it seems physically unlikely. We conclude that, in this simplified setup, a standing slow wave does not trigger the KHI without the involvement of additional physical processes.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"55 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77441313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}