Leveraging the datasets of galaxy triplets and large-scale filaments obtained from the Sloan Digital Sky Survey, we scrutinize the alignment of the three sides of the triangles formed by galaxy triplets and the normal vectors of the triplet planes within observed large-scale filaments. Our statistical investigation reveals that the longest and median sides of the galaxy triplets exhibit a robust alignment with the spines of their host large-scale filaments, while the shortest sides show no or only weak alignment with the filaments. Additionally, the normal vectors of triplets tend to be perpendicular to the filaments. The alignment signal diminishes rapidly with the increasing distance from the triplet to the filament spine, and is primarily significant for triplets located within distances shorter than 0.2 Mpc/h, with a confidence level exceeding 20σ. Moreover, in comparison to compact galaxy triplets, the alignment signal is more conspicuous among the loose triplets. This alignment analysis contributes to the formulation of a framework depicting the clustering and relaxation of galaxies within cosmological large-scale filament regimes, providing deeper insights into the intricate interactions between galaxies and their pivotal role in shaping galaxy groups.
{"title":"Galaxy Triplets Alignment in Large-scale Filaments","authors":"Yu Rong, Jinzhi Shen, Zi-chen Hua","doi":"10.1093/mnrasl/slae021","DOIUrl":"https://doi.org/10.1093/mnrasl/slae021","url":null,"abstract":"\u0000 Leveraging the datasets of galaxy triplets and large-scale filaments obtained from the Sloan Digital Sky Survey, we scrutinize the alignment of the three sides of the triangles formed by galaxy triplets and the normal vectors of the triplet planes within observed large-scale filaments. Our statistical investigation reveals that the longest and median sides of the galaxy triplets exhibit a robust alignment with the spines of their host large-scale filaments, while the shortest sides show no or only weak alignment with the filaments. Additionally, the normal vectors of triplets tend to be perpendicular to the filaments. The alignment signal diminishes rapidly with the increasing distance from the triplet to the filament spine, and is primarily significant for triplets located within distances shorter than 0.2 Mpc/h, with a confidence level exceeding 20σ. Moreover, in comparison to compact galaxy triplets, the alignment signal is more conspicuous among the loose triplets. This alignment analysis contributes to the formulation of a framework depicting the clustering and relaxation of galaxies within cosmological large-scale filament regimes, providing deeper insights into the intricate interactions between galaxies and their pivotal role in shaping galaxy groups.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":" 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140388862","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}
M. Healy-Kalesh, M. Darnley, E. J. Harvey, A. M. Newsam
The prototypical nova super-remnant (NSR) was uncovered around the most rapidly recurring nova (RN), M31N 2008-12a. Simulations of the growth of NSRs revealed that these large structures should exist around all novae, whether classical or recurrent. NSRs consist of large shell-like structures surrounding excavated cavities. Predictions, informed by these simulations, led to the discovery of an extended cavity coincident with the Galactic RN, RS Ophiuchi, in far-infrared archival IRAS images. We propose that this cavity is associated with RS Oph and is therefore evidence of another NSR to be uncovered.
{"title":"Discovery of a nova super-remnant cavity surrounding RS Ophiuchi","authors":"M. Healy-Kalesh, M. Darnley, E. J. Harvey, A. M. Newsam","doi":"10.1093/mnrasl/slae016","DOIUrl":"https://doi.org/10.1093/mnrasl/slae016","url":null,"abstract":"\u0000 The prototypical nova super-remnant (NSR) was uncovered around the most rapidly recurring nova (RN), M31N 2008-12a. Simulations of the growth of NSRs revealed that these large structures should exist around all novae, whether classical or recurrent. NSRs consist of large shell-like structures surrounding excavated cavities. Predictions, informed by these simulations, led to the discovery of an extended cavity coincident with the Galactic RN, RS Ophiuchi, in far-infrared archival IRAS images. We propose that this cavity is associated with RS Oph and is therefore evidence of another NSR to be uncovered.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":" 41","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139792652","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}
M. Healy-Kalesh, M. Darnley, E. J. Harvey, A. M. Newsam
The prototypical nova super-remnant (NSR) was uncovered around the most rapidly recurring nova (RN), M31N 2008-12a. Simulations of the growth of NSRs revealed that these large structures should exist around all novae, whether classical or recurrent. NSRs consist of large shell-like structures surrounding excavated cavities. Predictions, informed by these simulations, led to the discovery of an extended cavity coincident with the Galactic RN, RS Ophiuchi, in far-infrared archival IRAS images. We propose that this cavity is associated with RS Oph and is therefore evidence of another NSR to be uncovered.
{"title":"Discovery of a nova super-remnant cavity surrounding RS Ophiuchi","authors":"M. Healy-Kalesh, M. Darnley, E. J. Harvey, A. M. Newsam","doi":"10.1093/mnrasl/slae016","DOIUrl":"https://doi.org/10.1093/mnrasl/slae016","url":null,"abstract":"\u0000 The prototypical nova super-remnant (NSR) was uncovered around the most rapidly recurring nova (RN), M31N 2008-12a. Simulations of the growth of NSRs revealed that these large structures should exist around all novae, whether classical or recurrent. NSRs consist of large shell-like structures surrounding excavated cavities. Predictions, informed by these simulations, led to the discovery of an extended cavity coincident with the Galactic RN, RS Ophiuchi, in far-infrared archival IRAS images. We propose that this cavity is associated with RS Oph and is therefore evidence of another NSR to be uncovered.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"216 1-2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139852670","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}
In this letter, motivated by double-peaked broad Balmer emission lines probably related to tidal disruption events (TDEs), a potential TDE candidate is reported in SDSS J160536+134838 (=SDSS J1605) at z ∼ 0.44 having quasar-like spectrum but with double-peaked broad Hβ. The long-term CSS light curve can be naturally described by a main-sequence star of $2.82_{-0.19}^{+0.20}{rm M_odot }$ disrupted by the central black hole (BH) of $144_{-21}^{+26} times 10^6{rm M_odot }$ in SDSS J1605. Meanwhile, the ASAS-SN light curves afterwards show none apparent trend variability, indicating the bright CSS flare in SDSS J1605 unique and different enough from variability of normal AGN. Furthermore, there is a consistency between the TDE model determined sizes of debris with the sizes of emission regions for the double-peaked broad Hβ described by the accretion disk model, supporting the disk-like BLRs probably related to a central TDE in SDSS J1605. And the virial BH mass ∼7 times higher than the TDE model determined value can be naturally explained by R-L relation determined BLRs sizes very larger than the actual distance of emission regions related to TDEs debris in SDSS J1605. Although no clear conclusion on double-peaked broad lines absolutely related to TDEs, the results here provide clues to detect potential TDEs in AGN with double-peaked broad lines.
{"title":"A candidate for central tidal disruption event in the broad line AGN SDSS J1605 with double-peaked broad Hβ","authors":"XueGuang Zhang","doi":"10.1093/mnrasl/slae015","DOIUrl":"https://doi.org/10.1093/mnrasl/slae015","url":null,"abstract":"\u0000 In this letter, motivated by double-peaked broad Balmer emission lines probably related to tidal disruption events (TDEs), a potential TDE candidate is reported in SDSS J160536+134838 (=SDSS J1605) at z ∼ 0.44 having quasar-like spectrum but with double-peaked broad Hβ. The long-term CSS light curve can be naturally described by a main-sequence star of $2.82_{-0.19}^{+0.20}{rm M_odot }$ disrupted by the central black hole (BH) of $144_{-21}^{+26} times 10^6{rm M_odot }$ in SDSS J1605. Meanwhile, the ASAS-SN light curves afterwards show none apparent trend variability, indicating the bright CSS flare in SDSS J1605 unique and different enough from variability of normal AGN. Furthermore, there is a consistency between the TDE model determined sizes of debris with the sizes of emission regions for the double-peaked broad Hβ described by the accretion disk model, supporting the disk-like BLRs probably related to a central TDE in SDSS J1605. And the virial BH mass ∼7 times higher than the TDE model determined value can be naturally explained by R-L relation determined BLRs sizes very larger than the actual distance of emission regions related to TDEs debris in SDSS J1605. Although no clear conclusion on double-peaked broad lines absolutely related to TDEs, the results here provide clues to detect potential TDEs in AGN with double-peaked broad lines.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139854576","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}
In this letter, motivated by double-peaked broad Balmer emission lines probably related to tidal disruption events (TDEs), a potential TDE candidate is reported in SDSS J160536+134838 (=SDSS J1605) at z ∼ 0.44 having quasar-like spectrum but with double-peaked broad Hβ. The long-term CSS light curve can be naturally described by a main-sequence star of $2.82_{-0.19}^{+0.20}{rm M_odot }$ disrupted by the central black hole (BH) of $144_{-21}^{+26} times 10^6{rm M_odot }$ in SDSS J1605. Meanwhile, the ASAS-SN light curves afterwards show none apparent trend variability, indicating the bright CSS flare in SDSS J1605 unique and different enough from variability of normal AGN. Furthermore, there is a consistency between the TDE model determined sizes of debris with the sizes of emission regions for the double-peaked broad Hβ described by the accretion disk model, supporting the disk-like BLRs probably related to a central TDE in SDSS J1605. And the virial BH mass ∼7 times higher than the TDE model determined value can be naturally explained by R-L relation determined BLRs sizes very larger than the actual distance of emission regions related to TDEs debris in SDSS J1605. Although no clear conclusion on double-peaked broad lines absolutely related to TDEs, the results here provide clues to detect potential TDEs in AGN with double-peaked broad lines.
{"title":"A candidate for central tidal disruption event in the broad line AGN SDSS J1605 with double-peaked broad Hβ","authors":"XueGuang Zhang","doi":"10.1093/mnrasl/slae015","DOIUrl":"https://doi.org/10.1093/mnrasl/slae015","url":null,"abstract":"\u0000 In this letter, motivated by double-peaked broad Balmer emission lines probably related to tidal disruption events (TDEs), a potential TDE candidate is reported in SDSS J160536+134838 (=SDSS J1605) at z ∼ 0.44 having quasar-like spectrum but with double-peaked broad Hβ. The long-term CSS light curve can be naturally described by a main-sequence star of $2.82_{-0.19}^{+0.20}{rm M_odot }$ disrupted by the central black hole (BH) of $144_{-21}^{+26} times 10^6{rm M_odot }$ in SDSS J1605. Meanwhile, the ASAS-SN light curves afterwards show none apparent trend variability, indicating the bright CSS flare in SDSS J1605 unique and different enough from variability of normal AGN. Furthermore, there is a consistency between the TDE model determined sizes of debris with the sizes of emission regions for the double-peaked broad Hβ described by the accretion disk model, supporting the disk-like BLRs probably related to a central TDE in SDSS J1605. And the virial BH mass ∼7 times higher than the TDE model determined value can be naturally explained by R-L relation determined BLRs sizes very larger than the actual distance of emission regions related to TDEs debris in SDSS J1605. Although no clear conclusion on double-peaked broad lines absolutely related to TDEs, the results here provide clues to detect potential TDEs in AGN with double-peaked broad lines.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"109 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139794666","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}
There is a common assumption in the particulate disc community that the pressure in particulate discs is essentially zero and that the disc streamlines follow Keplerian orbits, in the absence of self-gravity or external perturbations. It is also often assumed that the fluid description of particulate discs is not valid in the presence of crossing orbits (e.g. from nonzero free eccentricities). These stem from the misconception that fluid pressure arises due to the (typically rare) collisions between particles and that the velocity of particles in fluids are single-valued in space. In reality, pressure is a statistical property of the particle distribution function which arises precisely because there is a distribution of velocities at a given position. In this letter we demonstrate, with simple examples, that pressure in particulate discs is non-zero and is related to the inclination and free eccentricity distributions of the constituent particles in the discs. This means many common models of debris discs implicitly assume a nonzero, and potentially quite significant, dust pressure. We shall also demonstrate that the bulk motion of the dust is not the same as the particle motion and that the presence of pressure gradients can lead to strong departures from Keplerian motion.
{"title":"Why dust pressure matters in debris discs","authors":"Elliot M. Lynch, J. Lovell, Antranik A. Sefilian","doi":"10.1093/mnrasl/slae011","DOIUrl":"https://doi.org/10.1093/mnrasl/slae011","url":null,"abstract":"\u0000 There is a common assumption in the particulate disc community that the pressure in particulate discs is essentially zero and that the disc streamlines follow Keplerian orbits, in the absence of self-gravity or external perturbations. It is also often assumed that the fluid description of particulate discs is not valid in the presence of crossing orbits (e.g. from nonzero free eccentricities). These stem from the misconception that fluid pressure arises due to the (typically rare) collisions between particles and that the velocity of particles in fluids are single-valued in space. In reality, pressure is a statistical property of the particle distribution function which arises precisely because there is a distribution of velocities at a given position. In this letter we demonstrate, with simple examples, that pressure in particulate discs is non-zero and is related to the inclination and free eccentricity distributions of the constituent particles in the discs. This means many common models of debris discs implicitly assume a nonzero, and potentially quite significant, dust pressure. We shall also demonstrate that the bulk motion of the dust is not the same as the particle motion and that the presence of pressure gradients can lead to strong departures from Keplerian motion.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"79 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140493393","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}
Solar-type stars form with a wide range of rotation rates Ω. A wide Ω range persists until a stellar age of t ∼ 0.6 Gyr, after which solar-type stars exhibit Skumanich spin-down where Ω∝t−1/2. Rotational evolution models incorporating polytropic stellar winds struggle to simultaneously reproduce these two regimes, namely the initially wide Ω range and the Skumanich spin-down without imposing an a-priori cap on the wind mass-loss rate. We show that a three-dimensional wind model driven by Alfvén waves and observational data yields wind torques that agree with the observed age distribution of Ω. In our models of the Sun and twenty-seven open cluster stars aged from 0.04 to 0.6 Gyr that have observationally derived surface magnetic maps and rotation rates, we find evidence of exponential spin-down in young stars that are rapid rotators and Skumanich spin-down for slow rotators. The two spin-down regimes emerge naturally from our data-driven models. Our modelling suggests that the observed age distribution of stellar rotation rates Ω arises as a consequence of magnetic field strength saturation in rapid rotators.
{"title":"Rotational evolution of young-to-old stars with data-driven three-dimensional wind models","authors":"D. Evensberget, A. Vidotto","doi":"10.1093/mnrasl/slae010","DOIUrl":"https://doi.org/10.1093/mnrasl/slae010","url":null,"abstract":"\u0000 Solar-type stars form with a wide range of rotation rates Ω. A wide Ω range persists until a stellar age of t ∼ 0.6 Gyr, after which solar-type stars exhibit Skumanich spin-down where Ω∝t−1/2. Rotational evolution models incorporating polytropic stellar winds struggle to simultaneously reproduce these two regimes, namely the initially wide Ω range and the Skumanich spin-down without imposing an a-priori cap on the wind mass-loss rate. We show that a three-dimensional wind model driven by Alfvén waves and observational data yields wind torques that agree with the observed age distribution of Ω. In our models of the Sun and twenty-seven open cluster stars aged from 0.04 to 0.6 Gyr that have observationally derived surface magnetic maps and rotation rates, we find evidence of exponential spin-down in young stars that are rapid rotators and Skumanich spin-down for slow rotators. The two spin-down regimes emerge naturally from our data-driven models. Our modelling suggests that the observed age distribution of stellar rotation rates Ω arises as a consequence of magnetic field strength saturation in rapid rotators.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139604048","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}
The image captured by SDO/AIA in the 193 Å ultraviolet channel from October 25-27, 2022, unveiled a remarkable trio of dark coronal holes near the heliocentric equator, forming a distinctive smiling face. Serendipitously, during that period, coronal radio science experiments were being conducted using the Akatsuki spacecraft to investigate turbulence regimes in the inner-middle corona and track the acceleration of solar wind streams. By analyzing Doppler frequency residuals, we derived valuable insights into plasma turbulence characteristics, estimated electron density fluctuations and flow speeds using isotropic quasi-static turbulence methods. The analysis consistently unveiled a shallow turbulence spectrum and flow speeds ranging from 180 to 400 km/s at heliocentric distances of 3 to 9 Rs. During this period, the solar wind flow speed, recorded at the L1 point near Earth, was of the order of 600 - 650 km/s. This presented a unique opportunity to delve into turbulence within the inner corona and explore the mechanisms responsible for energizing and accelerating high-speed streams emanating from these trans-equatorial coronal holes. The study also suggests the innovative use of spacecraft signals as radio beacons for enhanced forecasting of potential space weather events triggered by Earth-directed high-speed solar wind streams.
{"title":"Exploring the influence of the “Smiley Sun” on the dynamics of inner solar corona and near-Earth space environment","authors":"Richa N Jain, R. K. Choudhary, T. Imamura","doi":"10.1093/mnrasl/slae008","DOIUrl":"https://doi.org/10.1093/mnrasl/slae008","url":null,"abstract":"\u0000 The image captured by SDO/AIA in the 193 Å ultraviolet channel from October 25-27, 2022, unveiled a remarkable trio of dark coronal holes near the heliocentric equator, forming a distinctive smiling face. Serendipitously, during that period, coronal radio science experiments were being conducted using the Akatsuki spacecraft to investigate turbulence regimes in the inner-middle corona and track the acceleration of solar wind streams. By analyzing Doppler frequency residuals, we derived valuable insights into plasma turbulence characteristics, estimated electron density fluctuations and flow speeds using isotropic quasi-static turbulence methods. The analysis consistently unveiled a shallow turbulence spectrum and flow speeds ranging from 180 to 400 km/s at heliocentric distances of 3 to 9 Rs. During this period, the solar wind flow speed, recorded at the L1 point near Earth, was of the order of 600 - 650 km/s. This presented a unique opportunity to delve into turbulence within the inner corona and explore the mechanisms responsible for energizing and accelerating high-speed streams emanating from these trans-equatorial coronal holes. The study also suggests the innovative use of spacecraft signals as radio beacons for enhanced forecasting of potential space weather events triggered by Earth-directed high-speed solar wind streams.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"17 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139524923","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}
Cen X-3shows alternate spin-up/spin-down episodes lasting for tens of days. We study the orbital profiles and spectra of Cen X-3during these spin-up/spin-down intervals, using long-term data monitored by Fermi/GBM, Swift/BAT and MAXI/GSC. In spin-up intervals, its orbital profile in 2–10 keV is symmetrically peaked around orbital phase 0.42, while in spin-down intervals of similar fluxes and similar magnitudes of spin change rate, its profile reaches a peak around orbital phase 0.22 and then declines gradually. Such a distinct orbital difference between spin-up and spin-down states of similar flux is hard to explain in the standard disk model and indicates that its torque reversals are related to processes on the orbital scale. The durations of continuous spin-up/spin-down trend (tens of days) also point to a superorbital variation. One possible scenario is the irradiation-driven warping disk instability, which may produce a flipped inner disk for tens of days.
{"title":"Torque-dependent orbital modulation of X-ray pulsar Cen X-3","authors":"Zhenxuan Liao, Jiren Liu","doi":"10.1093/mnrasl/slae009","DOIUrl":"https://doi.org/10.1093/mnrasl/slae009","url":null,"abstract":"\u0000 Cen X-3shows alternate spin-up/spin-down episodes lasting for tens of days. We study the orbital profiles and spectra of Cen X-3during these spin-up/spin-down intervals, using long-term data monitored by Fermi/GBM, Swift/BAT and MAXI/GSC. In spin-up intervals, its orbital profile in 2–10 keV is symmetrically peaked around orbital phase 0.42, while in spin-down intervals of similar fluxes and similar magnitudes of spin change rate, its profile reaches a peak around orbital phase 0.22 and then declines gradually. Such a distinct orbital difference between spin-up and spin-down states of similar flux is hard to explain in the standard disk model and indicates that its torque reversals are related to processes on the orbital scale. The durations of continuous spin-up/spin-down trend (tens of days) also point to a superorbital variation. One possible scenario is the irradiation-driven warping disk instability, which may produce a flipped inner disk for tens of days.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"60 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139526687","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}
B. V. Soelen, P. Bordas, I. Negueruela, E. Wilhelmi, A. Papitto, M. Rib'o
HESS J1832−093 is a member of the rare class of gamma-ray binaries, as recently confirmed by the detection of orbitally modulated X-ray and gamma-ray emission with a period of ∼86 d. The spectral type of the massive companion star has been difficult to retrieve as there is no optical counterpart, but the system is coincident with a near-infrared source. Previous results have shown that the infrared counterpart is consistent with an O or B type star, but a clear classification is still lacking. We observed the counterpart twice, in 2019 and 2021, with the X-Shooter spectrograph operating on the VLT. The obtained spectra classify the counterpart as an O6 V type star. We estimate a distance to the source of 6.7 ± 0.5 kpc, although this estimate can be severely affected by the high extinction towards the source. This new O6 V classification for the companion star in HESS J1832−093 provides further support to an apparent grouping around a given spectral type for all discovered gamma-ray binaries that contain an O-type star. This may be due to the interplay between the initial mass function and the wind-momentum-luminosity relation.
HESS J1832-093 是罕见的伽马射线双星中的一员，最近探测到的周期为 ∼86 d 的轨道调制 X 射线和伽马射线发射证实了这一点。由于没有光学对应星，因此很难检索到大质量伴星的光谱类型，但该系统与一个近红外源重合。之前的研究结果表明，这颗红外伴星与 O 或 B 型恒星一致，但仍然缺乏明确的分类。我们在 2019 年和 2021 年利用在 VLT 上运行的 X-Shooter 摄谱仪对该对应星进行了两次观测。获得的光谱将这颗对应星归类为 O6 V 型星。我们估计与源的距离为 6.7 ± 0.5 kpc，不过这一估计值可能会受到源的高消光的严重影响。HESS J1832-093中伴星的这一新的O6 V型分类为所有发现的包含O型恒星的伽马射线双星围绕特定光谱型的明显分组提供了进一步的支持。这可能是由于初始质量函数和风动量-光度关系之间的相互作用造成的。
{"title":"NIR spectral classification of the companion in the gamma-ray binary HESS J1832–093 as an O6 V star","authors":"B. V. Soelen, P. Bordas, I. Negueruela, E. Wilhelmi, A. Papitto, M. Rib'o","doi":"10.1093/mnrasl/slae007","DOIUrl":"https://doi.org/10.1093/mnrasl/slae007","url":null,"abstract":"\u0000 HESS J1832−093 is a member of the rare class of gamma-ray binaries, as recently confirmed by the detection of orbitally modulated X-ray and gamma-ray emission with a period of ∼86 d. The spectral type of the massive companion star has been difficult to retrieve as there is no optical counterpart, but the system is coincident with a near-infrared source. Previous results have shown that the infrared counterpart is consistent with an O or B type star, but a clear classification is still lacking. We observed the counterpart twice, in 2019 and 2021, with the X-Shooter spectrograph operating on the VLT. The obtained spectra classify the counterpart as an O6 V type star. We estimate a distance to the source of 6.7 ± 0.5 kpc, although this estimate can be severely affected by the high extinction towards the source. This new O6 V classification for the companion star in HESS J1832−093 provides further support to an apparent grouping around a given spectral type for all discovered gamma-ray binaries that contain an O-type star. This may be due to the interplay between the initial mass function and the wind-momentum-luminosity relation.","PeriodicalId":18951,"journal":{"name":"Monthly Notices of the Royal Astronomical Society: Letters","volume":"51 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139533951","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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