Christopher Carr, Greg L. Bryan, Nicolás Garavito-Camargo, Gurtina Besla, David J. Setton, Kathryn V. Johnston and Kung-Yi Su
{"title":"The All-sky Impact of the LMC on the Milky Way Circumgalactic Medium","authors":"Christopher Carr, Greg L. Bryan, Nicolás Garavito-Camargo, Gurtina Besla, David J. Setton, Kathryn V. Johnston and Kung-Yi Su","doi":"10.3847/1538-4357/adbf1d","DOIUrl":"https://doi.org/10.3847/1538-4357/adbf1d","url":null,"abstract":"The first infall of the LMC into the Milky Way (MW) represents a large and recent disruption to the MW circumgalactic medium (CGM). In this work, we use idealized, hydrodynamical simulations of an MW-like CGM embedded in a dark matter halo with an infalling LMC-like satellite initialized with its own CGM to understand how the encounter is shaping the global physical and kinematic properties of the MW CGM. First, we find that the LMC drives order-unity enhancements in MW CGM density, temperature, and pressure due to a shock from the supersonic CGM–CGM collision. The resulting shock front extends from the LMC to beyond ∼R200,MW, amplifying column densities, X-ray brightness, thermal Sunyaev–Zeldovich distortion, and potentially synchrotron emission from cosmic rays over large angular scales across the southern hemisphere. Second, the MW’s reflex motion relative to its outer halo induces a dipole in CGM radial velocities, with vR ± 30–50 km s−1 at R > 50 kpc in the northern and southern hemispheres, respectively, consistent with measurements in the stellar halo. Finally, ram pressure strips most of the LMC’s CGM, leaving ∼108−9M⊙ warm ionized gas along the past orbit of the LMC, moving at high radial and/or tangential velocities ∼50–100 kpc from the MW. Massive satellites like the LMC leave their mark on the CGM structure of their host galaxies, and signatures of such interactions may be observable in key all-sky tracers of the MW CGM and those of other massive galaxies.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"56 36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836964","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}
Ming Lian, 茗 连, Jia-Shu Niu, 家树 牛, Hui-Fang Xue and 会芳 薛
{"title":"CY Aquarii: A Triple System with Twin Companions","authors":"Ming Lian, 茗 连, Jia-Shu Niu, 家树 牛, Hui-Fang Xue and 会芳 薛","doi":"10.3847/1538-4357/adc376","DOIUrl":"https://doi.org/10.3847/1538-4357/adc376","url":null,"abstract":"In this study, we conducted a comprehensive analysis of the SX Phoenicis (SX Phe) type star CY Aquarii (CY Aqr). Our investigation included a detailed O − C analysis based on a 90 yr observational data set, augmented by 1367 newly determined times of maximum light. The O − C diagram reveals that (i) the primary star of CY Aqr exhibits a linear period variation rate of (1/P0)(dP/dt) = (2.132 ± 0.002) × 10−8 yr−1 for its dominant pulsation mode; (ii) the primary star is disturbed by two companions and part of a triple system; (iii) Companion A has an orbital period of approximately 60.2 yr and Companion B has an orbital period of approximately 50.8 yr. It is highly probable that both Companion A and B are white dwarfs, with Companion A’s elliptical orbit displaying an eccentricity of e = 0.139 ± 0.002, which is the lowest confirmed value in similar binary and triple systems to date. Most notably, Companion A and B have masses that are identical within the uncertainties, with a mass ratio exceeding 0.99. Whether this is considered a coincidental event or the result of an underlying mechanism, CY Aqr is an exceptionally rare case that broadens our understanding of multiple star systems and offers a unique opportunity to delve into the enigmatic evolutionary histories of such configurations. Further intriguing characteristics of this system warrant investigation in future studies, based on additional observational data.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836989","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}
Hechao Chen, Hui Tian, Quanhao Zhang, Chuan Li, Chun Xia, Xianyong Bai, Zhenyong Hou, Kaifan Ji, Yuanyong Deng, Xiao Yang and Ziyao Hu
{"title":"Minifilament Eruptions as the Last Straw to Break the Equilibrium of a Giant Solar Filament","authors":"Hechao Chen, Hui Tian, Quanhao Zhang, Chuan Li, Chun Xia, Xianyong Bai, Zhenyong Hou, Kaifan Ji, Yuanyong Deng, Xiao Yang and Ziyao Hu","doi":"10.3847/1538-4357/adc12a","DOIUrl":"https://doi.org/10.3847/1538-4357/adc12a","url":null,"abstract":"Filament eruptions are magnetically driven violent explosions commonly observed on the Sun and late-type stars, sometimes leading to monster coronal mass ejections that directly affect the nearby planets’ environments. More than a century of research on solar filaments suggests that the slow evolution of photospheric magnetic fields plays a decisive role in initiating filament eruptions, but the underlying mechanism remains unclear. Using high-resolution observations from the Chinese Hα Solar Explorer, the Solar Upper Transition Region Imager, and the Solar Dynamics Observatory, we present direct evidence that a giant solar filament eruption is triggered by a series of minifilament eruptions occurring beneath it. These minifilaments, which are homologous to the giant filament but on a smaller tempo-spatial scale, sequently form and erupt due to extremely weak mutual flux disappearance of opposite-polarity photospheric magnetic fields. Through multifold magnetic interactions, these erupting minifilaments act as the last straw to break the force balance of the overlying giant filament and initiate its ultimate eruption. The results unveil a possible novel pathway for small-scale magnetic activities near the stellar surface to initiate spectacular filament eruptions, and provide new insight into the magnetic coupling of filament eruptions across different tempo-spatial scales.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836986","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}
Lang Cui, Pengfei Jiang, Tao An, Hongmin Cao, Ning Chang, Giulia Migliori, Marcello Giroletti, Sándor Frey, Jun Yang, Krisztina É. Gabányi, Xiaoyu Hong and Wenda Zhang
{"title":"Proper Motion and Natal Kick in the Galactic Black Hole X-Ray Binary AT2019wey","authors":"Lang Cui, Pengfei Jiang, Tao An, Hongmin Cao, Ning Chang, Giulia Migliori, Marcello Giroletti, Sándor Frey, Jun Yang, Krisztina É. Gabányi, Xiaoyu Hong and Wenda Zhang","doi":"10.3847/1538-4357/adc0f7","DOIUrl":"https://doi.org/10.3847/1538-4357/adc0f7","url":null,"abstract":"Understanding the formation mechanisms of stellar-mass black hole X-ray binaries (BHXBs) remains a fundamental challenge in astrophysics. The natal kick velocities imparted during black hole (BH) formation provide crucial constraints on these formation channels. In this work, we present a new-epoch very long baseline interferometry (VLBI) observation of the Galactic BHXB AT2019wey carried out in 2023. Combining with archival VLBI data from 2020, we successfully measure the proper motion of AT2019wey over a 3 yr timescale, namely, 0.78 ± 0.12 mas yr−1 in R.A. and −0.42 ± 0.07 mas yr−1 in decl. Employing the measured proper motion, we estimate its peculiar velocity and the potential kick velocity (PKV) through Monte Carlo simulations, incorporating uncertainties of its distance and radial velocity. The estimated PKV distributions and height above the Galactic plane suggest that AT2019wey’s BH likely formed through a supernova explosion rather than direct collapse.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837165","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}
Annu Bura, Tanmoy Samanta, Alphonse C. Sterling, Yajie Chen, Jayant Joshi, Vasyl Yurchyshyn and Ronald L. Moore
{"title":"Unveiling the Dynamics and Genesis of Small-scale Fine-structure Loops in the Lower Solar Atmosphere","authors":"Annu Bura, Tanmoy Samanta, Alphonse C. Sterling, Yajie Chen, Jayant Joshi, Vasyl Yurchyshyn and Ronald L. Moore","doi":"10.3847/1538-4357/adc109","DOIUrl":"https://doi.org/10.3847/1538-4357/adc109","url":null,"abstract":"Recent high-resolution solar observations have unveiled the presence of small-scale loop-like structures in the lower solar atmosphere, often referred to as unresolved fine structures, low-lying loops, and miniature hot loops. These structures undergo rapid changes within minutes, and their formation mechanism has remained elusive. In this study, we conducted a comprehensive analysis of two small loops utilizing data from the Interface Region Imaging Spectrograph (IRIS), the Goode Solar Telescope (GST) at Big Bear Solar Observatory, and the Atmospheric Imaging Assembly and the Helioseismic Magnetic Imager on board the Solar Dynamics Observatory, aiming to elucidate the underlying process behind their formation. The GST observations revealed that these loops, with lengths of ∼3.5 Mm and heights of ∼1 Mm, manifest as bright emission structures in Hα wing images, particularly prominent in the red wing. IRIS observations showcased these loops in 1330 Å slit-jaw images, with transition region (TR) and chromospheric line spectra exhibiting significant enhancement and broadening above the loops, indicative of plasmoid-mediated reconnection during their formation. Additionally, we observed upward-erupting jets above these loops across various passbands. Furthermore, differential emission measurement analysis reveals an enhanced emission measure at the location of these loops, suggesting the presence of plasma exceeding 1 MK. Based on our observations, we propose that these loops and associated jets align with the minifilament eruption model. Our findings suggest a unified mechanism governing the formation of small-scale loops and jets akin to larger-scale X-ray jets.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Redshift Evolution of the X-Ray and Ultraviolet Luminosity Relation of Quasars: Calibrated Results from SNe Ia","authors":"Xiaolei Li, Ryan E. Keeley and Arman Shafieloo","doi":"10.3847/1538-4357/adc2fe","DOIUrl":"https://doi.org/10.3847/1538-4357/adc2fe","url":null,"abstract":"Quasars could serve as standard candles if the relation between their ultraviolet (UV) and X-ray luminosities can be accurately calibrated. Previously, we developed a model-independent method to calibrate quasar standard candles using the distance–redshift relation reconstructed from Type Ia supernovae (SNe Ia) at z < 2 using Gaussian process regression. Interestingly, we found that the calibrated quasar standard candle data set preferred a deviation from ΛCDM at redshifts above z > 2. One possible interpretation of these findings is that the calibration parameters of the quasar UV and X-ray luminosity relationship evolves with redshift. In order to test the redshift dependence of the quasar calibration in a model-independent manner, we divided the quasar sample whose redshift overlaps with the redshift coverage of Pantheon+ SNe Ia compilation into two subsamples: a low-redshift quasar subsample and a high-redshift quasar subsample. Assuming all the quasar samples are reliable, our results show that there is about a 4σ inconsistency between the quasar parameters inferred from the subsamples without considering evolution. This inconsistency suggests the possibility of considering redshift evolution for the relationship between the quasars’ UV and X-ray luminosities. We then test an explicit parameterization of the redshift evolution of the quasar calibration parameters via γ(z) = γ0 + γ1(1 + z) and β(z) = β0 + β1(1 + z). Combining this redshift-dependent calibration relationship with the distance–redshift relationship reconstructed from the Pantheon+ supernova compilation, we find the high-redshift subsample and low-redshift subsample become consistent at the 2σ level, which means that the parameterized form of γ(z) and β(z) works well at describing the evolution of the quasar calibration parameters.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837199","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}
Nelson Caldwell, John C. Raymond, Knox S. Long and Myung Gyoon Lee
{"title":"Spectroscopy of Supernova Remnants and Candidates in M31","authors":"Nelson Caldwell, John C. Raymond, Knox S. Long and Myung Gyoon Lee","doi":"10.3847/1538-4357/adbf98","DOIUrl":"https://doi.org/10.3847/1538-4357/adbf98","url":null,"abstract":"With a star formation rate of order 0.4 M⊙ yr−1, M31 should have a significant population of supernova remnants (SNRs) and, in fact, 156 SNRs and SNR candidates have been suggested by J. H. Lee & M. G. Lee, by searching for nebulae with elevated [S ii]/Hα ratios in narrowband images. Here, we use a combination of low- and high-resolution optical spectroscopy obtained with Hectospec on the MMT to characterize 152 of these nebulae. Of these candidates, we find 93 nebulae that have [S ii]/Hα ratios that exceed 0.4, the traditional ratio used to separate SNRs from H ii regions, strongly suggesting that at least these objects are SNRs. Our high-resolution spectroscopy reveals 108 nebulae that have velocity widths in Hα (full width at 20% peak flux) that exceed 50 km s−1, significantly larger than found in H ii regions. There are 72 objects that satisfy both tests. Here, we discuss the spectroscopic characteristics of all of the objects in our sample, and the likelihood that other objects in the sample of J. H. Lee & M. G. Lee are also SNRs, and we briefly consider confirmation by X-ray, radio, and UV observations. We also discuss several new candidates that have been identified serendipitously in the course of examining a large amount of archival Hectospec data.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"V1047 Cen: The First Z And-type Outburst Observed in the Classical Nova Binary","authors":"Augustin Skopal and Natalia Shagatova","doi":"10.3847/1538-4357/adc0f6","DOIUrl":"https://doi.org/10.3847/1538-4357/adc0f6","url":null,"abstract":"In 2019, the classical nova V1047 Cen experienced an unusual outburst, the nature of which has not yet been clearly determined. In this paper, we show that the 2019 V1047 Cen outburst is of Z And-type—a type that is characteristic of and has so far been observed only in symbiotic binaries. We support our claim by modeling the near-ultraviolet to near-infrared spectral energy distribution, which revealed a close similarity between the fundamental parameters and the mass-loss rate of the burning white dwarf (WD) during the 2019 V1047 Cen outburst and those measured during Z And-type outbursts in symbiotic stars. All parameters are in good agreement with the theoretical prediction when the accretion rate exceeds the stable burning limit for WDs with masses ≲0.7 M⊙. Our analysis showed that after a nova explosion, the Z And-type outburst can occur not only in symbiotic binaries, but also in short-period cataclysmic variables, when the accretion-powered system changes to a nuclear-powered one as a consequence of the donor’s reaction to the nova explosion. Such a development promotes the production of Type Ia supernovae.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Demarcation Criterion for Hydrogen Burning of Millinovae","authors":"Izumi Hachisu and Mariko Kato","doi":"10.3847/1538-4357/adc107","DOIUrl":"https://doi.org/10.3847/1538-4357/adc107","url":null,"abstract":"Millinovae are a new class of transient supersoft X-ray sources with no clear signature of mass ejection. They show similar triangle shapes of V/I band light curves with 1000 times fainter peaks than typical classical novae. Maccarone et al. regarded the prototype millinova, ASASSN-16oh, as a dwarf nova and interpreted the supersoft X-rays to originate from an accretion belt on a white dwarf (WD). Kato et al. proposed a nova model induced by high-rate mass accretion during a dwarf nova outburst; the X-rays originate from the photosphere of a hydrogen-burning hot WD, whereas the V/I band photons are from the irradiated accretion disk. Because each peak brightness differs largely from millinova to millinova, we suspect that not all millinova candidates host a hydrogen-burning WD. Based on the light-curve analysis of the classical nova KT Eri that has a bright disk, we find that the disk is more than 2 magnitudes brighter when the disk is irradiated by the hydrogen-burning WD than when not irradiated. We present the demarcation criterion for hydrogen burning to be , where Iq and are the I magnitudes in quiescence and at maximum light, respectively. Among many candidates, this requirement is satisfied with the two millinovae in which soft X-rays were detected.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837166","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}
Lin He, Zhiyuan Li, Meicun Hou, Min Du, Taotao Fang and Wei Cui
{"title":"Probing the Hot Gaseous Halo of the Low-mass Disk Galaxy NGC 7793 with eROSITA and Chandra","authors":"Lin He, Zhiyuan Li, Meicun Hou, Min Du, Taotao Fang and Wei Cui","doi":"10.3847/1538-4357/adc0a0","DOIUrl":"https://doi.org/10.3847/1538-4357/adc0a0","url":null,"abstract":"Galaxy formation models predict that local galaxies are surrounded by hot X-ray-emitting halos, which are technically difficult to detect due to their extended and low surface brightness nature. Previous X-ray studies have mostly focused on disk galaxies more massive than the Milky Way, with essentially no consensus on the halo X-ray properties at the lower mass end. We utilize the early-released eROSITA and archival Chandra observations to analyze the diffuse X-ray emission of NGC 7793, a nearby spiral galaxy with an estimated stellar mass of only 3.2 × 109M⊙. We find evidence for extraplanar hot gas emission from both the radial and vertical soft X-ray intensity profiles, which spreads up to a galactocentric distance of ∼6 kpc, nearly 30% more extended than its stellar disk. Analysis of the eROSITA spectra indicates that the hot gas can be characterized by a temperature of keV, with 0.5–2 keV unabsorbed luminosity of 1.3 × 1038 erg s−1. We compare our results with the IllustrisTNG simulations and find overall consistence on the disk scale, whereas excessive emission at large radii is predicted by TNG50. This work provides the latest detection of hot corona around a low-mass galaxy, putting new constraints on state-of-the-art cosmological simulations. We also verify the detectability of hot circumgalactic medium around even low-mass spirals with future high-resolution X-ray spectrometers such as the Hot Universe Baryon Surveyor.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837162","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}
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