Jun Lin, Rui Guo, Sarah A Bird, Haijun Tian, Chao Liu, Chris Flynn, Gaochao Liu, Sheng Cui
We select 1,052,469 (754,635) thin disk stars from Gaia eDR3 and LAMOST DR7 in the range of Galactocentric radius R (guiding center radius Rg) from 8 to 11 kpc to investigate the asymmetries between the North and South of the disk midplane. More specifically we analyze the vertical velocity dispersion profiles ($sigma _{v_{z}}(z$)) in different bins of R (Rg) and [Fe/H]. We find troughs in the profiles of $sigma _{v_{z}}(z)$ located in both the North (z ∼ 0.7 kpc) and South (z ∼ −0.5 kpc) of the disk at all radial and chemical bins studied. The difference between the Northern and Southern vertical velocity dispersion profiles ($Delta sigma _{v_{z}}(|z|)$) shows a shift between curves of different R and Rg. A similar shift exists in these NS asymmetry profiles further divided into different [Fe/H] ranges. The sample binned with Rg more clearly displays the features in the velocity dispersion profiles. The shift in the peaks of the $Delta sigma _{v_{z}}$ profiles and the variation in the phase spiral shape binned by metallicity indicate the variation of the vertical potential profiles and the radial metallicity gradient. The wave-like signal in NS asymmetry of $sigma _{v_{z}}(z)$ largely originates from phase spiral; while the NS asymmetry profiles of [Fe/H] only display a weak wave-like feature near solar radius. We perform a test particle simulation to qualitatively reproduce the observed results. A quantitative explanation of the NS asymmetry in the metallicity profile needs careful consideration of the spiral shape and the perturbation model, and we leave this for future work.
{"title":"North-South asymmetries in the Galactic thin disk associated with the vertical phase spiral as seen using LAMOST-Gaia stars","authors":"Jun Lin, Rui Guo, Sarah A Bird, Haijun Tian, Chao Liu, Chris Flynn, Gaochao Liu, Sheng Cui","doi":"10.1093/mnras/stae175","DOIUrl":"https://doi.org/10.1093/mnras/stae175","url":null,"abstract":"We select 1,052,469 (754,635) thin disk stars from Gaia eDR3 and LAMOST DR7 in the range of Galactocentric radius R (guiding center radius Rg) from 8 to 11 kpc to investigate the asymmetries between the North and South of the disk midplane. More specifically we analyze the vertical velocity dispersion profiles ($sigma _{v_{z}}(z$)) in different bins of R (Rg) and [Fe/H]. We find troughs in the profiles of $sigma _{v_{z}}(z)$ located in both the North (z ∼ 0.7 kpc) and South (z ∼ −0.5 kpc) of the disk at all radial and chemical bins studied. The difference between the Northern and Southern vertical velocity dispersion profiles ($Delta sigma _{v_{z}}(|z|)$) shows a shift between curves of different R and Rg. A similar shift exists in these NS asymmetry profiles further divided into different [Fe/H] ranges. The sample binned with Rg more clearly displays the features in the velocity dispersion profiles. The shift in the peaks of the $Delta sigma _{v_{z}}$ profiles and the variation in the phase spiral shape binned by metallicity indicate the variation of the vertical potential profiles and the radial metallicity gradient. The wave-like signal in NS asymmetry of $sigma _{v_{z}}(z)$ largely originates from phase spiral; while the NS asymmetry profiles of [Fe/H] only display a weak wave-like feature near solar radius. We perform a test particle simulation to qualitatively reproduce the observed results. A quantitative explanation of the NS asymmetry in the metallicity profile needs careful consideration of the spiral shape and the perturbation model, and we leave this for future work.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"302 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139484142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A long-lived magnetar, potentially originating from a binary neutron star system, has been proposed to explain the extended emission observed in certain short-duration gamma-ray bursts (sGRBs), and is posited as a potential central engine to power the engine-fed kilonovae. Previously, the process by which energy is injected into the surrounding ejecta/jet was widely believed to be nearly isotropic. In this study, we employ special relativity magnetohydrodynamic (SRMHD) simulations to investigate the wind injection process from a magnetar central engine. We explore the dynamics and energy distribution within the system and found that the parameter α = uA/uMWN can be used to indicate the collimation of the magnetar wind energy injection, where uA is the local Alfven four-speed and uMWN is the four-speed of the magnetar wind nebular (MWN) formed from wind-ejecta collision. A significant portion of the injected energy from the magnetar spin-down wind will be channeled to the jet axis due to collimation within the MWN. Achieving isotropic energy injection requires a significantly small α that necessitates either an ultra-relativistic expanding MWN or an extremely low magnetization MWN, both of which are challenging to attain in sGRBs. Consequently, a considerably reduced energy budget (i.e. energy per solid angle reduced by a factor of up to 10 with respect to the value under isotropic assumption) is anticipated to be injected into the ejecta for engine-fed kilonovae. Engine-fed kilonovae would appear fainter than originally anticipated.
{"title":"Anisotropic energy injection from magnetar central engines in short GRBs","authors":"Yihan Wang, Bing Zhang, Zhaohuan Zhu","doi":"10.1093/mnras/stae136","DOIUrl":"https://doi.org/10.1093/mnras/stae136","url":null,"abstract":"A long-lived magnetar, potentially originating from a binary neutron star system, has been proposed to explain the extended emission observed in certain short-duration gamma-ray bursts (sGRBs), and is posited as a potential central engine to power the engine-fed kilonovae. Previously, the process by which energy is injected into the surrounding ejecta/jet was widely believed to be nearly isotropic. In this study, we employ special relativity magnetohydrodynamic (SRMHD) simulations to investigate the wind injection process from a magnetar central engine. We explore the dynamics and energy distribution within the system and found that the parameter α = uA/uMWN can be used to indicate the collimation of the magnetar wind energy injection, where uA is the local Alfven four-speed and uMWN is the four-speed of the magnetar wind nebular (MWN) formed from wind-ejecta collision. A significant portion of the injected energy from the magnetar spin-down wind will be channeled to the jet axis due to collimation within the MWN. Achieving isotropic energy injection requires a significantly small α that necessitates either an ultra-relativistic expanding MWN or an extremely low magnetization MWN, both of which are challenging to attain in sGRBs. Consequently, a considerably reduced energy budget (i.e. energy per solid angle reduced by a factor of up to 10 with respect to the value under isotropic assumption) is anticipated to be injected into the ejecta for engine-fed kilonovae. Engine-fed kilonovae would appear fainter than originally anticipated.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"46 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139484243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sushma Kurapati, Renée C Kraan-Korteweg, D J Pisano, Hao Chen, Sambatriniaina H A Rajohnson, Nadia Steyn, Bradley Frank, Paolo Serra, Sharmila Goedhart, Fernando Camilo
The Local Void is one of the nearest large voids, located at a distance of 23 Mpc. It lies largely behind the Galactic Bulge and is therefore extremely difficult to observe. We use Hi 21 cm emission observations from the SARAO MeerKAT Galactic Plane Survey (SMGPS) to study the Local Void and its surroundings over the Galactic longitude range 329○ < ℓ < 55○, Galactic latitude |b| < 1.5○, and redshift cz < 7500 $rm km , s^{-1}$. We have detected 291 galaxies to median rms sensitivity of 0.44 mJy per beam per 44 $rm km , s^{-1}$ channel. We find 17 galaxies deep inside the Void, 96 at the border of the Void, while the remaining 178 galaxies are in average density environments. The extent of the Void is ∼ 58 Mpc. It is severely under-dense for the longitude range 350○ < ℓ < 35○ up to redshift z < 4500 $rm km , s^{-1}$. The galaxies in the Void tend to have Hi masses that are lower (by approximately 0.25 dex) than their average density counterparts. We find several potential candidates for small groups of galaxies, of which two groups (with 3 members and 5 members) in the Void show signs of filamentary substructure within the Void.
本虚空是距离最近的大虚空之一，位于 23 Mpc 的距离。它主要位于银河凸起之后，因此极难观测。我们利用 SARAO MeerKAT 银河系平面巡天（SMGPS）的 Hi 21 cm 发射观测数据，研究了银河系经度范围 329○ < ℓ < 55○，银河系纬度 |b| < 1.5○，红移 cz < 7500 $rm km , s^{-1}$的本虚及其周围环境。我们探测到了291个星系，每个波束每44 $rm km , s^{-1}$通道的中位均方根灵敏度为0.44 mJy。我们在虚空深处发现了17个星系，在虚空边界发现了96个星系，剩下的178个星系处于平均密度环境中。虚空的范围是 ∼ 58 Mpc。在350○ < ℓ < 35○到红移z < 4500 $rm km, s^{-1}$的经度范围内，它的密度严重不足。虚空中的星系往往具有比它们的平均密度低（大约 0.25 dex）的 Hi 质量。我们发现了几个潜在的候选小星系群，其中虚空中的两个星系群（分别有3个和5个成员）显示出虚空中存在丝状亚结构的迹象。
{"title":"HI Galaxy Signatures in the SARAO MeerKAT Galactic Plane Survey - II. The Local Void and its substructure","authors":"Sushma Kurapati, Renée C Kraan-Korteweg, D J Pisano, Hao Chen, Sambatriniaina H A Rajohnson, Nadia Steyn, Bradley Frank, Paolo Serra, Sharmila Goedhart, Fernando Camilo","doi":"10.1093/mnras/stad3823","DOIUrl":"https://doi.org/10.1093/mnras/stad3823","url":null,"abstract":"The Local Void is one of the nearest large voids, located at a distance of 23 Mpc. It lies largely behind the Galactic Bulge and is therefore extremely difficult to observe. We use Hi 21 cm emission observations from the SARAO MeerKAT Galactic Plane Survey (SMGPS) to study the Local Void and its surroundings over the Galactic longitude range 329○ &lt; ℓ &lt; 55○, Galactic latitude |b| &lt; 1.5○, and redshift cz &lt; 7500 $rm km , s^{-1}$. We have detected 291 galaxies to median rms sensitivity of 0.44 mJy per beam per 44 $rm km , s^{-1}$ channel. We find 17 galaxies deep inside the Void, 96 at the border of the Void, while the remaining 178 galaxies are in average density environments. The extent of the Void is ∼ 58 Mpc. It is severely under-dense for the longitude range 350○ &lt; ℓ &lt; 35○ up to redshift z &lt; 4500 $rm km , s^{-1}$. The galaxies in the Void tend to have Hi masses that are lower (by approximately 0.25 dex) than their average density counterparts. We find several potential candidates for small groups of galaxies, of which two groups (with 3 members and 5 members) in the Void show signs of filamentary substructure within the Void.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"77 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139476412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ruth M E Kelly, Silvia Zane, Roberto Turolla, Roberto Taverna
Magnetars, the most strongly magnetised neutron stars, are among the most promising targets for X-ray polarimetry. The Imaging X-ray Polarimetry Explorer (IXPE), the first satellite devoted to exploring the sky in polarised X-rays, has observed four magnetars to date. A proper interpretation of IXPE results requires the development of new atmospheric models that can take into proper account the effects of the magnetised vacuum on par with those of the plasma. Here we investigate the effects of mode conversion at the vacuum resonance on the polarisation properties of magnetar emission by computing plane-parallel atmospheric models under varying conditions of magnetic field strength/orientation, effective temperature and allowing for either complete or partial adiabatic mode conversion. Complete mode conversion results in a switch of the dominant polarisation mode, from the extraordinary (X) to the ordinary (O) one, below an energy that decreases with increasing magnetic field strength, occurring at ≈0.5 keV for a magnetic field strength of B = 1014 G. Partial adiabatic mode conversion results in a reduced polarisation degree when compared with a standard plasma atmosphere. No dominant mode switch occurs for B = 1014 G while there are two switches for lower fields of B = 3 × 1013 G. Finally, by incorporating our models in a ray-tracing code, we computed the expected polarisation signal at infinity for different emitting regions on the star surface and for different viewing geometries. The observability of QED signatures with IXPE and with future soft X-ray polarimeters as REDSoX is discussed.
磁星是磁性最强的中子星，是 X 射线偏振测量最有希望的目标之一。成像 X 射线极化探测器（IXPE）是第一颗专门用偏振 X 射线探索天空的卫星，迄今已观测到四颗磁星。要正确解释 IXPE 的结果，需要开发新的大气模型，以适当考虑磁化真空与等离子体的影响。在这里，我们通过计算平面平行大气模型，在不同的磁场强度/方位、有效温度条件下，并允许完全或部分绝热模式转换，来研究真空共振时的模式转换对磁星发射极化特性的影响。完全模式转换会导致主要极化模式从非凡（X）模式转换为普通（O）模式，其能量随磁场强度的增加而降低，在磁场强度为 B = 1014 G 时，转换发生在 ≈0.5 keV 处。与标准等离子体大气相比，部分绝热模式转换导致极化程度降低。最后，通过将我们的模型纳入射线追踪代码，我们计算了恒星表面不同发射区域和不同观测几何形状下的无穷远处预期极化信号。讨论了用 IXPE 和未来的软 X 射线偏振计（如 REDSoX）观测 QED 信号的可观测性。
{"title":"X-ray Polarisation in Magnetar Atmospheres - Effects of Mode Conversion","authors":"Ruth M E Kelly, Silvia Zane, Roberto Turolla, Roberto Taverna","doi":"10.1093/mnras/stae159","DOIUrl":"https://doi.org/10.1093/mnras/stae159","url":null,"abstract":"Magnetars, the most strongly magnetised neutron stars, are among the most promising targets for X-ray polarimetry. The Imaging X-ray Polarimetry Explorer (IXPE), the first satellite devoted to exploring the sky in polarised X-rays, has observed four magnetars to date. A proper interpretation of IXPE results requires the development of new atmospheric models that can take into proper account the effects of the magnetised vacuum on par with those of the plasma. Here we investigate the effects of mode conversion at the vacuum resonance on the polarisation properties of magnetar emission by computing plane-parallel atmospheric models under varying conditions of magnetic field strength/orientation, effective temperature and allowing for either complete or partial adiabatic mode conversion. Complete mode conversion results in a switch of the dominant polarisation mode, from the extraordinary (X) to the ordinary (O) one, below an energy that decreases with increasing magnetic field strength, occurring at ≈0.5 keV for a magnetic field strength of B = 1014 G. Partial adiabatic mode conversion results in a reduced polarisation degree when compared with a standard plasma atmosphere. No dominant mode switch occurs for B = 1014 G while there are two switches for lower fields of B = 3 × 1013 G. Finally, by incorporating our models in a ray-tracing code, we computed the expected polarisation signal at infinity for different emitting regions on the star surface and for different viewing geometries. The observability of QED signatures with IXPE and with future soft X-ray polarimeters as REDSoX is discussed.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"67 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haochuan Yu, Suzanne Aigrain, Baptiste Klein, Oscar Barragán, Annelies Mortier, Niamh K O’Sullivan, Michael Cretignier
Although instruments for measuring the radial velocities (RVs) of stars now routinely reach sub-meter per second accuracy, the detection of low-mass planets is still very challenging. The rotational modulation and evolution of spots and/or faculae can induce variations in the RVs at the level of a few m/s in Sun-like stars. To overcome this, a multi-dimensional Gaussian Process framework has been developed to model the stellar activity signal using spectroscopic activity indicators together with the RVs. A recently published computationally efficient implementation of this framework, S+LEAF 2, enables the rapid analysis of large samples of targets with sizeable data sets. In this work, we apply this framework to HARPS observations of 268 well-observed targets with precisely determined stellar parameters. Our long-term goal is to quantify the effectiveness of this framework to model and mitigate activity signals for stars of different spectral types and activity levels. In this first paper in the series, we initially focus on the activity indicators (S-index and Bisector Inverse Slope), and use them to a) measure rotation periods for 49 slow rotators in our sample, b) explore the impact of these results on the spin-down of middle-aged late F, G & K stars, and c) explore indirectly how the spot to facular ratio varies across our sample. Our results should provide valuable clues for planning future RV planet surveys such as the Terra Hunting Experiment or the PLATO ground-based follow-up observations program, and help fine-tune current stellar structure and evolution models.
{"title":"Modelling stellar variability in archival HARPS data: I - Rotation and activity properties with multi-dimensional Gaussian processes","authors":"Haochuan Yu, Suzanne Aigrain, Baptiste Klein, Oscar Barragán, Annelies Mortier, Niamh K O’Sullivan, Michael Cretignier","doi":"10.1093/mnras/stae137","DOIUrl":"https://doi.org/10.1093/mnras/stae137","url":null,"abstract":"Although instruments for measuring the radial velocities (RVs) of stars now routinely reach sub-meter per second accuracy, the detection of low-mass planets is still very challenging. The rotational modulation and evolution of spots and/or faculae can induce variations in the RVs at the level of a few m/s in Sun-like stars. To overcome this, a multi-dimensional Gaussian Process framework has been developed to model the stellar activity signal using spectroscopic activity indicators together with the RVs. A recently published computationally efficient implementation of this framework, S+LEAF 2, enables the rapid analysis of large samples of targets with sizeable data sets. In this work, we apply this framework to HARPS observations of 268 well-observed targets with precisely determined stellar parameters. Our long-term goal is to quantify the effectiveness of this framework to model and mitigate activity signals for stars of different spectral types and activity levels. In this first paper in the series, we initially focus on the activity indicators (S-index and Bisector Inverse Slope), and use them to a) measure rotation periods for 49 slow rotators in our sample, b) explore the impact of these results on the spin-down of middle-aged late F, G & K stars, and c) explore indirectly how the spot to facular ratio varies across our sample. Our results should provide valuable clues for planning future RV planet surveys such as the Terra Hunting Experiment or the PLATO ground-based follow-up observations program, and help fine-tune current stellar structure and evolution models.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"17 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marco Palla, Ilse De Looze, Monica Relaño, Stefan van der Giessen, Pratika Dayal, Andrea Ferrara, Raffaella Schneider, Luca Graziani, Hiddo S B Algera, Manuel Aravena, Rebecca A A Bowler, Alexander P S Hygate, Hanae Inami, Ivana van Leeuwen, Rychard Bouwens, Jacqueline Hodge, Renske Smit, Mauro Stefanon, Paul van der Werf
ALMA observations revealed the presence of significant amounts of dust in the first Gyr of Cosmic time. However, the metal and dust buildup picture remains very uncertain due to the lack of constraints on metallicity. JWST has started to reveal the metal content of high-redshift targets, which may lead to firmer constraints on high-redshift dusty galaxies evolution. In this work, we use detailed chemical and dust evolution models to explore the evolution of galaxies within the ALMA REBELS survey, testing different metallicity scenarios that could be inferred from JWST observations. In the models, we track the buildup of stellar mass by using non-parametric SFHs for REBELS galaxies. Different scenarios for metal and dust evolution are simulated by allowing different prescriptions for gas flows and dust processes. The model outputs are compared with measured dust scaling relations, by employing metallicity-dependent calibrations for the gas mass based on the [C ii] 158 μm line. Independently of the galaxies metal content, we found no need for extreme dust prescriptions to explain the dust masses revealed by ALMA. However, different levels of metal enrichment will lead to different dominant dust production mechanisms, with stardust production dominant over other ISM dust processes only in the metal-poor case. This points out how metallicity measurements from JWST will significantly improve our understanding of the dust buildup in high-redshift galaxies. We also show that models struggle to reproduce observables such as dust-to-gas and dust-to-stellar ratios simultaneously, possibly indicating an overestimation of the gas mass through current calibrations, especially at high metallicities.
{"title":"Metal and dust evolution in ALMA REBELS galaxies: insights for future JWST observations","authors":"Marco Palla, Ilse De Looze, Monica Relaño, Stefan van der Giessen, Pratika Dayal, Andrea Ferrara, Raffaella Schneider, Luca Graziani, Hiddo S B Algera, Manuel Aravena, Rebecca A A Bowler, Alexander P S Hygate, Hanae Inami, Ivana van Leeuwen, Rychard Bouwens, Jacqueline Hodge, Renske Smit, Mauro Stefanon, Paul van der Werf","doi":"10.1093/mnras/stae160","DOIUrl":"https://doi.org/10.1093/mnras/stae160","url":null,"abstract":"ALMA observations revealed the presence of significant amounts of dust in the first Gyr of Cosmic time. However, the metal and dust buildup picture remains very uncertain due to the lack of constraints on metallicity. JWST has started to reveal the metal content of high-redshift targets, which may lead to firmer constraints on high-redshift dusty galaxies evolution. In this work, we use detailed chemical and dust evolution models to explore the evolution of galaxies within the ALMA REBELS survey, testing different metallicity scenarios that could be inferred from JWST observations. In the models, we track the buildup of stellar mass by using non-parametric SFHs for REBELS galaxies. Different scenarios for metal and dust evolution are simulated by allowing different prescriptions for gas flows and dust processes. The model outputs are compared with measured dust scaling relations, by employing metallicity-dependent calibrations for the gas mass based on the [C ii] 158 μm line. Independently of the galaxies metal content, we found no need for extreme dust prescriptions to explain the dust masses revealed by ALMA. However, different levels of metal enrichment will lead to different dominant dust production mechanisms, with stardust production dominant over other ISM dust processes only in the metal-poor case. This points out how metallicity measurements from JWST will significantly improve our understanding of the dust buildup in high-redshift galaxies. We also show that models struggle to reproduce observables such as dust-to-gas and dust-to-stellar ratios simultaneously, possibly indicating an overestimation of the gas mass through current calibrations, especially at high metallicities.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"4 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tsang Keung Chan, Alejandro Benítez-Llambay, Tom Theuns, Carlos Frenk, Richard Bower
An ionization front (I-front) that propagates through an inhomogeneous medium is slowed down by self-shielding and recombinations. We perform cosmological radiation hydrodynamics simulations of the I-front propagation during the epoch of cosmic reionization. The simulations resolve gas in mini-halos (halo mass 104 ≲ Mh[M⊙] ≲ 108) that could dominate recombinations, in a computational volume that is large enough to sample the abundance of such halos. The numerical resolution is sufficient (gas-particle mass ∼20M⊙, spatial resolution <0.1 ckpc) to allow accurate modelling of the hydrodynamic response of gas to photo-heating. We quantify the photo-evaporation time of mini-halos as a function of Mh and its dependence on the photo-ionization rate, Γ−12, and the redshift of reionization, zi. The recombination rate can be enhanced over that of a uniform medium by a factor ∼10 − 20 early on. The peak value increases with Γ−12 and decreases with zi, due to the enhanced contribution from mini-halos. The clumping factor, cr, decreases to a factor of a few at ∼100 Myr after the passage of the I-front when the mini-halos have been photo-evaporated; this asymptotic value depends only weakly on Γ−12. Recombinations increase the required number of photons per baryon to reionize the Universe by 20-100 per cent, with the higher value occurring when Γ−12 is high and zi is low. We complement the numerical simulations with simple analytical models for the evaporation rate and the inverse Strömgren layer. The study also demonstrates the proficiency and potential of sph-m1rt to address astrophysical problems in high-resolution cosmological simulations.
{"title":"The impact and response of mini-halos and the inter-halo medium on cosmic reionization","authors":"Tsang Keung Chan, Alejandro Benítez-Llambay, Tom Theuns, Carlos Frenk, Richard Bower","doi":"10.1093/mnras/stae114","DOIUrl":"https://doi.org/10.1093/mnras/stae114","url":null,"abstract":"An ionization front (I-front) that propagates through an inhomogeneous medium is slowed down by self-shielding and recombinations. We perform cosmological radiation hydrodynamics simulations of the I-front propagation during the epoch of cosmic reionization. The simulations resolve gas in mini-halos (halo mass 104 ≲ Mh[M⊙] ≲ 108) that could dominate recombinations, in a computational volume that is large enough to sample the abundance of such halos. The numerical resolution is sufficient (gas-particle mass ∼20M⊙, spatial resolution &lt;0.1 ckpc) to allow accurate modelling of the hydrodynamic response of gas to photo-heating. We quantify the photo-evaporation time of mini-halos as a function of Mh and its dependence on the photo-ionization rate, Γ−12, and the redshift of reionization, zi. The recombination rate can be enhanced over that of a uniform medium by a factor ∼10 − 20 early on. The peak value increases with Γ−12 and decreases with zi, due to the enhanced contribution from mini-halos. The clumping factor, cr, decreases to a factor of a few at ∼100 Myr after the passage of the I-front when the mini-halos have been photo-evaporated; this asymptotic value depends only weakly on Γ−12. Recombinations increase the required number of photons per baryon to reionize the Universe by 20-100 per cent, with the higher value occurring when Γ−12 is high and zi is low. We complement the numerical simulations with simple analytical models for the evaporation rate and the inverse Strömgren layer. The study also demonstrates the proficiency and potential of sph-m1rt to address astrophysical problems in high-resolution cosmological simulations.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"31 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we revisit the relationship between [O III] line width w90 (as the indicator of AGN outflow velocity) and the radio emission in RQQs by employing a large sample of Type I quasars (∼37, 000) selected from the Sloan Digital Sky Survey (SDSS) Data Release Sixteen. By median stacking the radio images (to include the dominant fraction of individually radio non-detected RQQs) of Karl G. Jansky Very Large Array (VLA) Sky Survey (VLASS) for subsamples of RQQs with different w90, our study demonstrates that, the correlation between w90 and radio emission in our SDSS RQQs is significant, and remains solid after controlling the effects of black hole mass, quasar luminosity, Eddington ratio and redshift. This intrinsic link supports that the [O III] outflows in quasars, most likely resulted from wide-angled sub-relativistic quasar winds launched from the accretion disc, could make a dominant contribution to radio emission in the general RQQs. Alternatively, the correlation may be attributed to low-power jets in RQQs if they are ubiquitous and could efficiently enhance the [O III] width through interacting with the ISM. Meanwhile, the star-formation rates traced by the flux ratio of [Ne V]/[O II] emission lines display no dependence on w90 after controlling the effects of black hole mass, quasar luminosity, Eddington ratio and redshift. This suggests that the stronger radio emission in RQQs with larger w90 could not be attributed to outflow enhanced (positive feedback) star formation in the hosts. However, this also indicates the outflows, though exhibiting robust correlation with radio power, produce neither positive nor negative feedback to the star formation in their hosts.
{"title":"Outflow-related radio emission in radio-quiet quasars","authors":"Mai Liao, Junxian Wang, Wenke Ren, Minhua Zhou","doi":"10.1093/mnras/stae126","DOIUrl":"https://doi.org/10.1093/mnras/stae126","url":null,"abstract":"In this work, we revisit the relationship between [O III] line width w90 (as the indicator of AGN outflow velocity) and the radio emission in RQQs by employing a large sample of Type I quasars (∼37, 000) selected from the Sloan Digital Sky Survey (SDSS) Data Release Sixteen. By median stacking the radio images (to include the dominant fraction of individually radio non-detected RQQs) of Karl G. Jansky Very Large Array (VLA) Sky Survey (VLASS) for subsamples of RQQs with different w90, our study demonstrates that, the correlation between w90 and radio emission in our SDSS RQQs is significant, and remains solid after controlling the effects of black hole mass, quasar luminosity, Eddington ratio and redshift. This intrinsic link supports that the [O III] outflows in quasars, most likely resulted from wide-angled sub-relativistic quasar winds launched from the accretion disc, could make a dominant contribution to radio emission in the general RQQs. Alternatively, the correlation may be attributed to low-power jets in RQQs if they are ubiquitous and could efficiently enhance the [O III] width through interacting with the ISM. Meanwhile, the star-formation rates traced by the flux ratio of [Ne V]/[O II] emission lines display no dependence on w90 after controlling the effects of black hole mass, quasar luminosity, Eddington ratio and redshift. This suggests that the stronger radio emission in RQQs with larger w90 could not be attributed to outflow enhanced (positive feedback) star formation in the hosts. However, this also indicates the outflows, though exhibiting robust correlation with radio power, produce neither positive nor negative feedback to the star formation in their hosts.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"1 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sergei N Yurchenko, Alec Owens, Kyriaki Kefala, Jonathan Tennyson
The MM ro-vibrational line list for methane (12CH4) is presented; MM covers wavelengths λ > 0.83 μm (wavenumbers up to 12 000 cm−1) and contains over 50 billion transitions between 9 155 208 states with total angular momentum J ≤ 60. MM was generated through solution of the nuclear motion Schrödinger equation using variational program trove for an empirically-derived potential energy surface (PES) and a new high-level ab initio dipole moment surface. The PES was constructed by fitting the ro-vibrational energies of CH4 to a set of highly accurate, experimentally-derived energies. Molecular states are classified using the Td(M) symmetry group and are fully assigned with rotation and vibration quantum numbers. The MM line list is adapted to high-resolution applications by replacing the calculated ro-vibrational energies with the experimentally-derived values where available, namely for 23 208 states with J ≤ 27 below 9986 cm−1. Doing so leads to over 1 000 000 experimentally-derived CH4 lines compared to approximately 330 000 lines of 12CH4 in the HITRAN database. The MM line list is shown to be more complete than the recent HITEMP methane line list. Methane spectra computed using MM across a broad range of temperatures and wavenumbers show excellent agreement with experiment. The MM line list supersedes the previous ExoMol methane line lists 10to10 and 30to10 both in terms accuracy and coverage. Together with the pre-computed ExoMolOP molecular atmospheric opacity tables, it is now the recommended CH4 dataset in the ExoMol database (www.exomol.com).
{"title":"ExoMol line lists – LVII: High accuracy ro-vibrational line list for methane (CH4)","authors":"Sergei N Yurchenko, Alec Owens, Kyriaki Kefala, Jonathan Tennyson","doi":"10.1093/mnras/stae148","DOIUrl":"https://doi.org/10.1093/mnras/stae148","url":null,"abstract":"The MM ro-vibrational line list for methane (12CH4) is presented; MM covers wavelengths λ &gt; 0.83 μm (wavenumbers up to 12 000 cm−1) and contains over 50 billion transitions between 9 155 208 states with total angular momentum J ≤ 60. MM was generated through solution of the nuclear motion Schrödinger equation using variational program trove for an empirically-derived potential energy surface (PES) and a new high-level ab initio dipole moment surface. The PES was constructed by fitting the ro-vibrational energies of CH4 to a set of highly accurate, experimentally-derived energies. Molecular states are classified using the Td(M) symmetry group and are fully assigned with rotation and vibration quantum numbers. The MM line list is adapted to high-resolution applications by replacing the calculated ro-vibrational energies with the experimentally-derived values where available, namely for 23 208 states with J ≤ 27 below 9986 cm−1. Doing so leads to over 1 000 000 experimentally-derived CH4 lines compared to approximately 330 000 lines of 12CH4 in the HITRAN database. The MM line list is shown to be more complete than the recent HITEMP methane line list. Methane spectra computed using MM across a broad range of temperatures and wavenumbers show excellent agreement with experiment. The MM line list supersedes the previous ExoMol methane line lists 10to10 and 30to10 both in terms accuracy and coverage. Together with the pre-computed ExoMolOP molecular atmospheric opacity tables, it is now the recommended CH4 dataset in the ExoMol database (www.exomol.com).","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"88 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present 206 unpublished optical spectra of 104 type II supernovae obtained by the Xinglong 2.16m telescope and Lijiang 2.4m telescope during the period from 2011 to 2018, spanning the phases from about 1 to 200 days after the SN explosion. The spectral line identifications, evolution of line velocities and pseudo equivalent widths, as well as correlations between some important spectral parameters are presented. Our sample displays a large range in expansion velocities. For instance, the Fe ii 5169 velocities measured from spectra at t ∼ 50 days after the explosion vary from 2000 km s−1 to 5500 km s−1, with an average value of 3872 ± 949 km s−1. Power-law functions can be used to fit the velocity evolution, with the power-law exponent quantifying the velocity decline rate. We found an anticorrelation existing between Hβ velocity at mid-plateau phase and its velocity decay exponent, SNe II with higher velocities tending to have smaller velocity decay rate. Moreover, we noticed that the velocity decay rate inferred from the Balmer lines (i.e., Hα and Hβ) have moderate correlations with the ratio of absorption to emission for Hα (a/e). In our sample, two objects show possibly flash-ionized features at early phases. Besides, we noticed that multiple high-velocity components may exist on the blue side of hydrogen lines of SN 2013ab, possibly suggesting that these features arise from complex line forming region. All our spectra can be found in WISeREP and Zenodo.
我们展示了兴隆2.16米望远镜和丽江2.4米望远镜在2011年至2018年期间获得的104颗II型超新星的206颗未发表的光学光谱，时间跨度从SN爆炸后约1天到200天。文中介绍了光谱线的识别、线速度和伪等效宽度的演变，以及一些重要光谱参数之间的相关性。我们的样本显示出很大的膨胀速度范围。例如，从爆炸后 t ∼ 50 天的光谱中测得的 Fe ii 5169 速度从 2000 km s-1 到 5500 km s-1 不等，平均值为 3872 ± 949 km s-1。幂律函数可用于拟合速度演化，幂律指数可量化速度下降率。我们发现高原中期的 Hβ 速度与其速度衰减指数之间存在反相关关系，速度越高的 SNe II 的速度衰减率往往越小。此外，我们还注意到，从巴尔默线（即Hα和Hβ）推断出的速度衰减率与Hα的吸收和发射比（a/e）有适度的相关性。在我们的样本中，有两个天体在早期阶段可能出现了闪电离特征。此外，我们注意到在SN 2013ab的氢线蓝边可能存在多个高速成分，这可能表明这些特征来自复杂的线形成区域。我们的所有光谱都可以在 WISeREP 和 Zenodo 中找到。
{"title":"A spectral data release for 104 Type II Supernovae from the Tsinghua Supernova Group","authors":"Han Lin, Xiaofeng Wang, Jujia Zhang, Shengyu Yan, Danfeng Xiang, Tianmeng Zhang, Xulin Zhao, Xinghan Zhang, Hanna Sai, Liming Rui, Jun Mo, Gaobo Xi, Fang Huang, Xue Li, Yongzhi Cai, Weili Lin, Jie Lin, Chengyuan Wu, Jicheng Zhang, Zhihao Chen, Zhitong Li, Wenxiong Li, Linyi Li, Kaicheng Zhang, Cheng Miao, Juncheng Chen, Zhou Fan, Jianning Fu, Shengbang Qian, Hong Wu, Xue-Bing Wu, Jingzhi Yan, Huawei Zhang, Junbo Zhang, Liyun Zhang, Jie Zheng, Qian Zhai","doi":"10.1093/mnras/stae144","DOIUrl":"https://doi.org/10.1093/mnras/stae144","url":null,"abstract":"We present 206 unpublished optical spectra of 104 type II supernovae obtained by the Xinglong 2.16m telescope and Lijiang 2.4m telescope during the period from 2011 to 2018, spanning the phases from about 1 to 200 days after the SN explosion. The spectral line identifications, evolution of line velocities and pseudo equivalent widths, as well as correlations between some important spectral parameters are presented. Our sample displays a large range in expansion velocities. For instance, the Fe ii 5169 velocities measured from spectra at t ∼ 50 days after the explosion vary from 2000 km s−1 to 5500 km s−1, with an average value of 3872 ± 949 km s−1. Power-law functions can be used to fit the velocity evolution, with the power-law exponent quantifying the velocity decline rate. We found an anticorrelation existing between Hβ velocity at mid-plateau phase and its velocity decay exponent, SNe II with higher velocities tending to have smaller velocity decay rate. Moreover, we noticed that the velocity decay rate inferred from the Balmer lines (i.e., Hα and Hβ) have moderate correlations with the ratio of absorption to emission for Hα (a/e). In our sample, two objects show possibly flash-ionized features at early phases. Besides, we noticed that multiple high-velocity components may exist on the blue side of hydrogen lines of SN 2013ab, possibly suggesting that these features arise from complex line forming region. All our spectra can be found in WISeREP and Zenodo.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"6 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139459663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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