The Astrophysical Journal最新文献_第8页

Why Are Optical Coronal Lines Faint in Active Galactic Nuclei? 为什么活动星系核中的光学日冕线很淡？

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad7a79

Jeffrey D. McKaig, Shobita Satyapal, Ari Laor, Nicholas P. Abel, Sara M. Doan, Claudio Ricci and Jenna M. Cann

{"title":"Why Are Optical Coronal Lines Faint in Active Galactic Nuclei?","authors":"Jeffrey D. McKaig, Shobita Satyapal, Ari Laor, Nicholas P. Abel, Sara M. Doan, Claudio Ricci and Jenna M. Cann","doi":"10.3847/1538-4357/ad7a79","DOIUrl":"https://doi.org/10.3847/1538-4357/ad7a79","url":null,"abstract":"Forbidden collisionally excited optical atomic transitions from high-ionization-potential (IP ≥ 54.8 eV) ions, such as Ca4+, Ne4+, Fe6+, Fe10+, Fe13+, Ar9+, and S11+, are known as optical coronal lines (CLs). The spectral energy distributions (SEDs) of active galactic nuclei (AGNs) typically extend to hundreds of electron volts and above, which should be able to produce such highly ionized gas. However, optical CLs are often not detected in AGNs. Here we use photoionization calculations with the cloudy spectral synthesis code to determine possible reasons for the rarity of these optical CLs. We calculate CL luminosities and equivalent widths from radiation-pressure-confined photoionized gas slabs exposed to an AGN continuum. We consider the role of dust, metallicity, and ionizing SED in the formation of optical CLs. We find that (i) dust reduces the strength of most CLs by ∼3 orders of magnitude, primarily as a result of depletion of metals onto the dust grains; (ii) in contrast to the CLs, the more widely observed lower-IP optical lines such as [O iii] 5007 Å are less affected by depletion, and some are actually enhanced in dusty gas; and (iii) many optical CLs become detectable in dustless gas, and are particularly strong for a hard ionizing SED. This implies that prominent CL emission likely originates in dustless gas. Our calculations also suggest optical CL emission is enhanced in galaxies with low-mass black holes characterized by a harder radiation field and a low dust-to-metals ratio. The fact that optical CLs are not widely observed in the early Universe with JWST may point to rapid dust formation at high redshift.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"249 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670320","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}

引用次数: 0

Identifying the Host Galaxies of Supermassive Black Hole Binaries Found by Pulsar Timing Arrays 识别脉冲星定时阵列发现的超大质量黑洞双星的寄主星系

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad7b14

Polina Petrov, Stephen R. Taylor, Maria Charisi and Chung-Pei Ma

{"title":"Identifying the Host Galaxies of Supermassive Black Hole Binaries Found by Pulsar Timing Arrays","authors":"Polina Petrov, Stephen R. Taylor, Maria Charisi and Chung-Pei Ma","doi":"10.3847/1538-4357/ad7b14","DOIUrl":"https://doi.org/10.3847/1538-4357/ad7b14","url":null,"abstract":"Supermassive black hole binaries (SMBHBs) are thought to form in galaxy mergers, possessing the potential to produce electromagnetic (EM) radiation as well as gravitational waves (GWs) detectable with pulsar timing arrays (PTAs). Once GWs from individually resolved SMBHBs are detected, the identification of the host galaxy will be a major challenge due to the ambiguity in possible EM signatures and the poor localization capability of PTAs. To aid EM observations in choosing follow-up sources, we use NANOGrav’s galaxy catalog to quantify the number of plausible hosts in both realistic and idealistic scenarios. We outline a host identification pipeline that injects a single-source GW signal into a simulated PTA data set, recovers the signal using production-level techniques, quantifies the localization region and number of galaxies contained therein, and finally imposes cuts on the galaxies using parameter estimates from the GW search. In an ideal case, the 90% credible areas span 29–241 deg2, containing about 14–341 galaxies. After cuts, the number of galaxies remaining ranges from 22 at worst to one true host at best. In a realistic case, these areas range from 287 to 530 deg2 and enclose about 285–1238 galaxies. After cuts, the number of galaxies is 397 at worst and 27 at best. While the signal-to-noise ratio is the primary determinant of the localization area of a given source, we find that the area is also influenced by the proximity to nearby pulsars on the sky and the binary chirp mass.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670321","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}

引用次数: 0

A Hierarchical Bayesian Approach to Point-source Analysis in High-energy Neutrino Telescopes 高能中微子望远镜点源分析的层次贝叶斯方法

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad7fe9

Francesca Capel, Julian Kuhlmann, Christian Haack, Martin Ha Minh, Hans Niederhausen and Lisa Schumacher

{"title":"A Hierarchical Bayesian Approach to Point-source Analysis in High-energy Neutrino Telescopes","authors":"Francesca Capel, Julian Kuhlmann, Christian Haack, Martin Ha Minh, Hans Niederhausen and Lisa Schumacher","doi":"10.3847/1538-4357/ad7fe9","DOIUrl":"https://doi.org/10.3847/1538-4357/ad7fe9","url":null,"abstract":"We propose a novel approach to the detection of point-like sources of high-energy neutrinos. Motivated by evidence for emerging sources in existing data, we focus on the characterization and interpretation of these sources rather than the rejection of the background-only hypothesis. The hierarchical Bayesian model is implemented in the Stan platform, enabling computation of the posterior distribution with a Hamiltonian Monte Carlo algorithm. We simulate a population of weak neutrino sources detected by the IceCube experiment and use the resulting data set to demonstrate and validate our framework. We show that even for the challenging case of sources at the threshold of detection and using limited prior information, it is possible to correctly infer the source properties. Additionally, we demonstrate how modeling flexible connections between similar sources can be used to recover the contribution of sources that would not be detectable individually. While a direct comparison of our method to existing approaches is challenged by the fundamental differences in frequentist and Bayesian frameworks, we draw parallels where possible. In particular, we highlight how including more complexity into the source modeling can increase the sensitivity to sources and their populations.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670335","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}

引用次数: 0

Low [O/Fe] Ratio in a Luminous Galaxy at the Early Cosmic Epoch (z > 10): Signature of Short Delay Time or Bright Hypernovae/Pair-instability Supernovae? 早期宇宙纪（z > 10）发光星系中的低[O/Fe]比：短延迟时间或明亮超新星/成对不稳定超新星的特征？

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad84e8

Minami Nakane, Masami Ouchi, Kimihiko Nakajima, Yuichi Harikane, Nozomu Tominaga, Koh Takahashi, Daichi Kashino, Hiroto Yanagisawa, Kuria Watanabe, Ken’ichi Nomoto, Yuki Isobe, Moka Nishigaki, Miho N. Ishigaki, Yoshiaki Ono and Yui Takeda

{"title":"Low [O/Fe] Ratio in a Luminous Galaxy at the Early Cosmic Epoch (z > 10): Signature of Short Delay Time or Bright Hypernovae/Pair-instability Supernovae?","authors":"Minami Nakane, Masami Ouchi, Kimihiko Nakajima, Yuichi Harikane, Nozomu Tominaga, Koh Takahashi, Daichi Kashino, Hiroto Yanagisawa, Kuria Watanabe, Ken’ichi Nomoto, Yuki Isobe, Moka Nishigaki, Miho N. Ishigaki, Yoshiaki Ono and Yui Takeda","doi":"10.3847/1538-4357/ad84e8","DOIUrl":"https://doi.org/10.3847/1538-4357/ad84e8","url":null,"abstract":"We present an [O/Fe] ratio of a luminous galaxy GN-z11 at z = 10.60 derived with the deep public JWST/NIRSpec data. We fit the medium-resolution grating (G140M, G235M, and G395M) data with the model spectra consisting of BPASS-stellar and Cloudy-nebular spectra in the rest-frame UV wavelength ranges with Fe absorption lines, carefully masking the other emission and absorption lines in the same manner as previous studies conducted for lower-redshift (z ∼ 2–6) galaxies with oxygen abundance measurements. We obtain an Fe-rich abundance ratio , which is confirmed with the independent deep prism data as well as by the classic 1978 index method. This [O/Fe] measurement is lower than that measured for star-forming galaxies at z ∼ 2–3. Because z = 10.60 is an early epoch after the Big Bang (∼430 Myr) and the first star formation (likely ∼200 Myr), it is difficult to produce Fe by Type Ia supernovae (SNe Ia), which requires sufficient delay time for white-dwarf formation and gas accretion. The Fe-rich abundance ratio in GN-z11 suggests that the delay time is short or that the major Fe enrichment is not accomplished by SNe Ia but by bright hypernovae (BrHNe) and/or pair-instability supernovae (PISNe), where the yield models of BrHNe and PISNe explain Fe, Ne, and O abundance ratios of GN-z11. The [O/Fe] measurement is not too low to rule out the connection between GN-z11 and globular clusters (GCs) previously suggested by the nitrogen abundance but rather supports the connection with a GC population at high [N/O] if a metal dilution process exists.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670973","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}

引用次数: 0

The SAGA Survey. III. A Census of 101 Satellite Systems around Milky Way–mass Galaxies SAGA 调查。III.银河系质量星系周围 101 个卫星系统的普查

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad64c4

Yao-Yuan Mao, Marla Geha, Risa H. Wechsler, Yasmeen Asali, Yunchong Wang, Erin Kado-Fong, Nitya Kallivayalil, Ethan O. Nadler, Erik J. Tollerud, Benjamin Weiner, Mithi A. C. de los Reyes and John F. Wu

{"title":"The SAGA Survey. III. A Census of 101 Satellite Systems around Milky Way–mass Galaxies","authors":"Yao-Yuan Mao, Marla Geha, Risa H. Wechsler, Yasmeen Asali, Yunchong Wang, Erin Kado-Fong, Nitya Kallivayalil, Ethan O. Nadler, Erik J. Tollerud, Benjamin Weiner, Mithi A. C. de los Reyes and John F. Wu","doi":"10.3847/1538-4357/ad64c4","DOIUrl":"https://doi.org/10.3847/1538-4357/ad64c4","url":null,"abstract":"We present Data Release 3 (DR3) of the Satellites Around Galactic Analogs (SAGA) Survey, a spectroscopic survey characterizing satellite galaxies around Milky Way (MW)-mass galaxies. The SAGA Survey DR3 includes 378 satellites identified across 101 MW-mass systems in the distance range of 25–40.75 Mpc, and an accompanying redshift catalog of background galaxies (including about 46,000 taken by SAGA) in the SAGA footprint of 84.7 deg2. The number of confirmed satellites per system ranges from zero to 13, in the stellar mass range of 106−10M⊙. Based on a detailed completeness model, this sample accounts for 94% of the true satellite population down to M⋆ = 107.5M⊙. We find that the mass of the most massive satellite in SAGA systems is the strongest predictor of satellite abundance; one-third of the SAGA systems contain LMC-mass satellites, and they tend to have more satellites than the MW. The SAGA satellite radial distribution is less concentrated than the MW's, and the SAGA quenched fraction below 108.5M⊙ is lower than the MW's, but in both cases, the MW is within 1σ of SAGA system-to-system scatter. SAGA satellites do not exhibit a clear corotating signal as has been suggested in the MW/M31 satellite systems. Although the MW differs in many respects from the typical SAGA system, these differences can be reconciled if the MW is an older, slightly less massive host with a recently accreted LMC/SMC system.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670319","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}

引用次数: 0

Bright in the Black: Searching for Electromagnetic Counterparts to Gravitational-wave Candidates in LIGO-Virgo-KAGRA Observation Runs with AstroSat-CZTI 黑中透亮：利用 AstroSat-CZTI 在 LIGO-Virgo-KAGRA 观测运行中寻找引力波候选者的电磁对应物

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad84e6

Gaurav Waratkar, Varun Bhalerao and Dipankar Bhattacharya

{"title":"Bright in the Black: Searching for Electromagnetic Counterparts to Gravitational-wave Candidates in LIGO-Virgo-KAGRA Observation Runs with AstroSat-CZTI","authors":"Gaurav Waratkar, Varun Bhalerao and Dipankar Bhattacharya","doi":"10.3847/1538-4357/ad84e6","DOIUrl":"https://doi.org/10.3847/1538-4357/ad84e6","url":null,"abstract":"GW150914 marked the start of the gravitational wave (GW) era with the direct detection of a binary black hole (BBH) merger by the LIGO-Virgo GW detectors. The event was tentatively associated with a signal detected by the Fermi Gamma-ray Burst Monitor (GBM), which hinted toward electromagnetic emission associated with compact object coalescence. The detection of a short gamma-ray burst (GRB) associated with GW170817, along with several multiwavelength detections, truly established that compact object mergers are indeed multimessenger events. The CadmiumZincTelluride Imager (CZTI) on board AstroSat can search for X-ray counterparts of the GW events and has detected over 650 GRBs in the 8.5 yr since it was launched. We present results from our searches for counterparts coincident with GW triggers from the first three LIGO-Virgo-KAGRA (LVK) GW Transient Catalogs. For 71 out of 90 GW events for which AstroSat-CZTI data was available, we undertook a systematic search for temporally coincident transients in the 20–200 keV band and detected no X-ray counterparts. We evaluate the upper limits on the maximum possible flux from the source in a 100 s window centered around each trigger, consistent with the GW localization of the event. Thanks to the sensitivity of CZTI, these upper limits are competitive with those from other spacecraft. We use these upper limits to constrain theoretical models that predict high-energy counterparts to BBH mergers. We also discuss the probability of nondetections of BBH mergers at different luminosities and the implications of such nondetections from the ongoing fourth observing run of the LVK detectors.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670336","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}

引用次数: 0

Physical Models for the Astrophysical Population of Black Holes: Application to the Bump in the Mass Distribution of Gravitational-wave Sources 黑洞天体物理群体的物理模型：引力波源质量分布凹凸的应用

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad8572

Jacob Golomb, Maximiliano Isi and Will M. Farr

{"title":"Physical Models for the Astrophysical Population of Black Holes: Application to the Bump in the Mass Distribution of Gravitational-wave Sources","authors":"Jacob Golomb, Maximiliano Isi and Will M. Farr","doi":"10.3847/1538-4357/ad8572","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8572","url":null,"abstract":"Gravitational-wave observations of binary black holes have revealed unexpected structure in the black hole mass distribution. Previous studies employ physically motivated phenomenological models and infer the parameters that control the features of the mass distribution that are allowed in their model, associating the constraints on those parameters with their physical motivations a posteriori. In this work, we take an alternative approach in which we introduce a model parameterizing the underlying stellar and core-collapse physics and obtaining the remnant black hole distribution as a derived by-product. In doing so, we constrain the stellar physics necessary to explain the astrophysical distribution of black hole properties under a given model. We apply this to the mapping between initial mass and remnant black hole mass, accounting for mass-dependent mass loss using a simple parameterized description. Allowing the parameters of the initial mass–remnant mass relationship to evolve with redshift permits correlated and physically reasonable changes to features in the mass function. We find that the current data are consistent with no redshift evolution in the core–remnant mass relationship, but place only weak constraints on the change of these parameters. This procedure can be applied to modeling any physical process underlying the astrophysical distribution. We illustrate this by applying our model to the pulsational pair instability supernova (PPISN) process, previously proposed as an explanation for the observed excess of black holes at ∼35 M⊙. Placing constraints on the reaction rates necessary to explain the PPISN parameters, we concur with previous results in the literature that the peak observed at ∼35 M⊙ is unlikely to be a signature from the PPISN process as presently understood.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"172 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670340","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}

引用次数: 0

The SAGA Survey. V. Modeling Satellite Systems around Milky Way–Mass Galaxies with Updated UniverseMachine SAGA Survey.V. 利用更新的宇宙机器模拟银河系质量星系周围的卫星系统

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad7f4c

Yunchong Wang, Ethan O. Nadler, Yao-Yuan Mao, Risa H. Wechsler, Tom Abel, Peter Behroozi, Marla Geha, Yasmeen Asali, Mithi A. C. de los Reyes, Erin Kado-Fong, Nitya Kallivayalil, Erik J. Tollerud, Benjamin Weiner and John F. Wu

{"title":"The SAGA Survey. V. Modeling Satellite Systems around Milky Way–Mass Galaxies with Updated UniverseMachine","authors":"Yunchong Wang, Ethan O. Nadler, Yao-Yuan Mao, Risa H. Wechsler, Tom Abel, Peter Behroozi, Marla Geha, Yasmeen Asali, Mithi A. C. de los Reyes, Erin Kado-Fong, Nitya Kallivayalil, Erik J. Tollerud, Benjamin Weiner and John F. Wu","doi":"10.3847/1538-4357/ad7f4c","DOIUrl":"https://doi.org/10.3847/1538-4357/ad7f4c","url":null,"abstract":"Environment plays a critical role in shaping the assembly of low-mass galaxies. Here, we use the UniverseMachine (UM) galaxy–halo connection framework and Data Release 3 of the Satellites Around Galactic Analogs (SAGA) Survey to place dwarf galaxy star formation and quenching into a cosmological context. UM is a data-driven forward model that flexibly parameterizes galaxy star formation rates (SFRs) using only halo mass and assembly history. We add a new quenching model to UM, tailored for galaxies with m⋆ ≲ 109M⊙, and constrain the model down to m⋆ ≳ 107M⊙ using new SAGA observations of 101 satellite systems around Milky Way (MW)–mass hosts and a sample of isolated field galaxies in a similar mass range from the Sloan Digital Sky Survey. The new best-fit model, “UM-SAGA,” reproduces the satellite stellar mass functions, average SFRs, and quenched fractions in SAGA satellites while keeping isolated dwarfs mostly star-forming. The enhanced quenching in satellites relative to isolated field galaxies leads the model to maximally rely on halo assembly to explain the observed environmental quenching. Extrapolating the model down to m⋆ ∼ 106.5M⊙ yields a quenched fraction of ≳30% for isolated field galaxies and ≳80% for satellites of MW-mass hosts at this stellar mass. Spectroscopic surveys can soon test this specific prediction to reveal the relative importance of internal feedback, cessation of mass and gas accretion, satellite-specific gas processes, and reionization for the evolution of faint low-mass galaxies.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670334","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}

引用次数: 0

Kinematic Insights into Luminous Blue Variables and B[e] Supergiants 对发光蓝变星和B[e]超巨星的运动学洞察

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad8134

Julian A. Deman and M. S. Oey

{"title":"Kinematic Insights into Luminous Blue Variables and B[e] Supergiants","authors":"Julian A. Deman and M. S. Oey","doi":"10.3847/1538-4357/ad8134","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8134","url":null,"abstract":"Recent work suggests that many luminous blue variables (LBVs) and B[e] supergiants (sgB[e]) are isolated, implying that they may be products of massive binaries, kicked by partner supernovae. However, the evidence is somewhat complex and controversial. To test this scenario, we measure the proper-motion velocities for these objects in the LMC and SMC, using Gaia Data Release 3. Our LMC results show that the kinematics, luminosities, and IR properties point to LBVs and sgB[e] stars being distinct classes. We find that Class 1 LBVs, which have dusty nebulae, and sgB[e] stars both show velocity distributions comparable to that of SMC field OBe stars, which are known to have experienced SN kicks. The sgB[e] stars are faster, plausibly due to their lower average masses. However, Class 2 LBVs, which are luminous objects without dusty nebulae, show no signs of acceleration, therefore suggesting that they are single stars, pre-SN binaries, or perhaps binary mergers. The candidate LBV Class 3 stars, which are dominated by hot dust, are all confirmed sgB[e] stars; their luminosities and velocities show that they simply represent the most luminous and massive of the sgB[e] class. There are very few SMC objects, but the sgB[e] stars are faster than their LMC counterparts, which may be consistent with expectations that lower-metallicity binaries are tighter, causing faster ejections. We also examine the distinct class of dust-free, weak-lined sgB[e] stars, finding that the SMC objects have the fastest velocities of the entire sample.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670972","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}

引用次数: 0

Study of Evolution and Geo-effectiveness of Coronal Mass Ejection–Coronal Mass Ejection Interactions Using Magnetohydrodynamic Simulations with SWASTi Framework 利用 SWASTi 框架的磁流体动力学模拟研究日冕物质抛射-日冕物质抛射相互作用的演变和地球效应

The Astrophysical Journal Pub Date : 2024-11-18 DOI: 10.3847/1538-4357/ad8084

Prateek Mayank, Stefan Lotz, Bhargav Vaidya, Wageesh Mishra and D. Chakrabarty

{"title":"Study of Evolution and Geo-effectiveness of Coronal Mass Ejection–Coronal Mass Ejection Interactions Using Magnetohydrodynamic Simulations with SWASTi Framework","authors":"Prateek Mayank, Stefan Lotz, Bhargav Vaidya, Wageesh Mishra and D. Chakrabarty","doi":"10.3847/1538-4357/ad8084","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8084","url":null,"abstract":"The geo-effectiveness of coronal mass ejections (CMEs) is a critical area of study in space weather, particularly in the lesser-explored domain of CME–CME interactions and their geomagnetic consequences. This study leverages the Space Weather Adaptive SimulaTion framework to perform 3D MHD simulation of a range of CME–CME interaction scenarios within realistic solar wind conditions. The focus is on the dynamics of the initial magnetic flux, speed, density, and tilt of CMEs, and their individual and combined impacts on the disturbance storm time (Dst) index. Additionally, the kinematic, magnetic, and structural impacts on the leading CME, as well as the mixing of both CMEs, are analyzed. Time-series in situ studies are conducted through virtual spacecraft positioned along three different longitudes at 1 au. Our findings reveal that CME–CME interactions are nonuniform along different longitudes, due to the inhomogeneous ambient solar wind conditions. A significant increase in the momentum and kinetic energy of the leading CME is observed due to collisions with the trailing CME, along with the formation of reverse shocks in cases of strong interaction. These reverse shocks lead to complex wave patterns inside CME2, which can prolong the storm recovery phase. Furthermore, we observe that the minimum Dst value decreases with an increase in the initial density, tilt, and speed of the trailing CME.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670339","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}

引用次数: 0