Hannah Übler, Francesco D’Eugenio, Michele Perna, Santiago Arribas, Gareth C Jones, Andrew J Bunker, Stefano Carniani, Stéphane Charlot, Roberto Maiolino, Bruno Rodríguez del Pino, Chris J Willott, Torsten Böker, Giovanni Cresci, Nimisha Kumari, Isabella Lamperti, Eleonora Parlanti, Jan Scholtz, Giacomo Venturi
We present rest-frame optical data of the $zsim 4$ submillimetre galaxy GN20 obtained with the JWST Near Infrared Spectrograph (NIRSpec) in integral field spectroscopy mode. The H$alpha$ emission is asymmetric and clumpy and extends over a projected distance of >15 kpc. To first order, the large-scale ionized gas kinematics are consistent with a turbulent ($sigma sim 90$ km s$^{-1}$), rotating disc ($v_{rm rot}sim 500$ km s$^{-1}$), congruent with previous studies of its molecular and ionized gas kinematics. However, we also find clear evidence for non-circular motions in the H$alpha$ kinematics. We discuss their possible connection with various scenarios, such as external perturbations, accretion, or radial flows. In the centre of GN20, we find broad-line emission (full width at half-maximum $sim 1000{-}2000$ km s$^{-1}$) in the H$alpha$ + [N ii] complex, suggestive of fast, active galactic nucleus-driven winds or, alternatively, of the broad-line region of an active black hole. Elevated values of [N ii] $lambda 6583$/H$alpha gt 0.4$ and of the Hα equivalent width EW(H$alpha) gt 6$ Å throughout large parts of GN20 suggest that feedback from the active black hole is able to photoionize the interstellar medium. Our data corroborate that GN20 offers a unique opportunity to observe key processes in the evolution of the most massive present-day galaxies acting in concert, over 12 billion years ago.
我们展示了用JWST近红外摄谱仪（NIRSpec）在积分场光谱模式下获得的$zsim 4$亚毫米波星系GN20的静帧光学数据。H$alpha$发射是不对称的、团块状的，延伸的投影距离为>15 kpc。在一阶，大尺度电离气体运动学与湍流（$sigma sim 90$ km s$^{-1}$）、旋转圆盘（$v_{rm rot}sim 500$ km s$^{-1}$）一致，这与之前对其分子和电离气体运动学的研究一致。不过，我们也发现了 H$alpha$ 运动学中存在非圆运动的明显证据。我们讨论了它们与外部扰动、吸积或径向流等各种情况的可能联系。在GN20的中心，我们发现了H$alpha$ + [N ii]复合体的宽线辐射（半最大全宽为$sim 1000{-}2000$ km s$^{-1}$），这表明存在由活跃星系核驱动的快速风，或者是活跃黑洞的宽线区域。在GN20的大部分区域，[N ii] $lambda 6583$/H$alpha gt 0.4$和Hα等效宽度EW(H$alpha) gt 6$埃的升高值表明，来自活动黑洞的反馈能够使星际介质光离子化。我们的数据证实，GN20提供了一个独特的机会，可以观测到120多亿年前现今质量最大的星系协同演化的关键过程。
{"title":"GA-NIFS: NIRSpec reveals evidence for non-circular motions and AGN feedback in GN20","authors":"Hannah Übler, Francesco D’Eugenio, Michele Perna, Santiago Arribas, Gareth C Jones, Andrew J Bunker, Stefano Carniani, Stéphane Charlot, Roberto Maiolino, Bruno Rodríguez del Pino, Chris J Willott, Torsten Böker, Giovanni Cresci, Nimisha Kumari, Isabella Lamperti, Eleonora Parlanti, Jan Scholtz, Giacomo Venturi","doi":"10.1093/mnras/stae1993","DOIUrl":"https://doi.org/10.1093/mnras/stae1993","url":null,"abstract":"We present rest-frame optical data of the $zsim 4$ submillimetre galaxy GN20 obtained with the JWST Near Infrared Spectrograph (NIRSpec) in integral field spectroscopy mode. The H$alpha$ emission is asymmetric and clumpy and extends over a projected distance of >15 kpc. To first order, the large-scale ionized gas kinematics are consistent with a turbulent ($sigma sim 90$ km s$^{-1}$), rotating disc ($v_{rm rot}sim 500$ km s$^{-1}$), congruent with previous studies of its molecular and ionized gas kinematics. However, we also find clear evidence for non-circular motions in the H$alpha$ kinematics. We discuss their possible connection with various scenarios, such as external perturbations, accretion, or radial flows. In the centre of GN20, we find broad-line emission (full width at half-maximum $sim 1000{-}2000$ km s$^{-1}$) in the H$alpha$ + [N ii] complex, suggestive of fast, active galactic nucleus-driven winds or, alternatively, of the broad-line region of an active black hole. Elevated values of [N ii] $lambda 6583$/H$alpha gt 0.4$ and of the Hα equivalent width EW(H$alpha) gt 6$ Å throughout large parts of GN20 suggest that feedback from the active black hole is able to photoionize the interstellar medium. Our data corroborate that GN20 offers a unique opportunity to observe key processes in the evolution of the most massive present-day galaxies acting in concert, over 12 billion years ago.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"169 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177547","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}
Dinko Milaković, John K Webb, Paolo Molaro, Chung-Chi Lee, Prashin Jethwa, Guido Cupani, Michael T Murphy, Louise Welsh, Valentina D’Odorico, Stefano Cristiani, Ricardo Génova Santos, Carlos J A P Martins, Nelson J Nunes, Tobias M Schmidt, Francesco A Pepe, Maria Rosa Zapatero Osorio, Yann Alibert, J I González Hernández, Paolo Di Marcantonio, Enric Palle, Rafael Rebolo, Nuno C Santos, Sérgio G Sousa, Alejandro Suárez Mascareño
Chemical evolution models predict a gradual build-up of 13C in the Universe, based on empirical nuclear reaction rates and assumptions on the properties of stellar populations. However, old metal-poor stars within the Galaxy contain more 13C than is predicted, suggesting that further refinements to the models are necessary. Gas at high-redshift provides important supplementary information at metallicities $-2lesssim left[{rm Fe/H}right]lesssim -1$, for which there are only a few measurements in the Galaxy. We obtained new, high-quality, VLT/ESPRESSO observations of the QSO B1331$+$170 and used them to measure 12C/13C in the damped Lyman-$alpha$ system (DLA) at $z_{rm abs}=1.776$, with $left[{rm Fe/H}right]$ = −1.27. ai-vpfit, an artificial intelligence tool based on genetic algorithms and guided by a spectroscopic information criterion, was used to explore different possible kinematic structures of the carbon gas. Three hundred independent ai-vpfit models of the absorption system were produced using pre-set 12C/13C values, ranging from 4 to 500. Our results show that ${rm ^{12}C / ^{13}C}=28.5^{+51.5}_{-10.4}$, suggesting a possibility of 13C production at low metallicity.
{"title":"Isotopic abundance of carbon in the DLA towards QSO B1331+170","authors":"Dinko Milaković, John K Webb, Paolo Molaro, Chung-Chi Lee, Prashin Jethwa, Guido Cupani, Michael T Murphy, Louise Welsh, Valentina D’Odorico, Stefano Cristiani, Ricardo Génova Santos, Carlos J A P Martins, Nelson J Nunes, Tobias M Schmidt, Francesco A Pepe, Maria Rosa Zapatero Osorio, Yann Alibert, J I González Hernández, Paolo Di Marcantonio, Enric Palle, Rafael Rebolo, Nuno C Santos, Sérgio G Sousa, Alejandro Suárez Mascareño","doi":"10.1093/mnras/stae2056","DOIUrl":"https://doi.org/10.1093/mnras/stae2056","url":null,"abstract":"Chemical evolution models predict a gradual build-up of 13C in the Universe, based on empirical nuclear reaction rates and assumptions on the properties of stellar populations. However, old metal-poor stars within the Galaxy contain more 13C than is predicted, suggesting that further refinements to the models are necessary. Gas at high-redshift provides important supplementary information at metallicities $-2lesssim left[{rm Fe/H}right]lesssim -1$, for which there are only a few measurements in the Galaxy. We obtained new, high-quality, VLT/ESPRESSO observations of the QSO B1331$+$170 and used them to measure 12C/13C in the damped Lyman-$alpha$ system (DLA) at $z_{rm abs}=1.776$, with $left[{rm Fe/H}right]$ = −1.27. ai-vpfit, an artificial intelligence tool based on genetic algorithms and guided by a spectroscopic information criterion, was used to explore different possible kinematic structures of the carbon gas. Three hundred independent ai-vpfit models of the absorption system were produced using pre-set 12C/13C values, ranging from 4 to 500. Our results show that ${rm ^{12}C / ^{13}C}=28.5^{+51.5}_{-10.4}$, suggesting a possibility of 13C production at low metallicity.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"173 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256164","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}
L Rhodes, A J van der Horst, J S Bright, J K Leung, G E Anderson, R Fender, J F Agüí Fernandez, M Bremer, P Chandra, D Dobie, W Farah, S Giarratana, K Gourdji, D A Green, E Lenc, M J Michałowski, T Murphy, A J Nayana, A W Pollak, A Rowlinson, F Schussler, A Siemion, R L C Starling, P Scott, C C Thöne, D Titterington, A de Ugarte Postigo
We present radio observations of the long-duration gamma-ray burst (GRB) 221009A which has become known to the community as the Brightest Of All Time or the BOAT. Our observations span the first 475 days post-burst and three orders of magnitude in observing frequency, from 0.15 to 230 GHz. By combining our new observations with those available in the literature, we have the most detailed radio data set in terms of cadence and spectral coverage of any GRB to date, which we use to explore the spectral and temporal evolution of the afterglow. By testing a series of phenomenological models, we find that three separate synchrotron components best explain the afterglow. The high temporal and spectral resolution allows us to conclude that standard analytical afterglow models are unable to explain the observed evolution of GRB 221009A. We explore where the discrepancies between the observations and the models are most significant and place our findings in the context of the most well-studied GRB radio afterglows to date. Our observations are best explained by three synchrotron emitting regions which we interpret as a forward shock, a reverse shock and an additional shock potentially from a cocoon or wider outflow. Finally, we find that our observations do not show any evidence of any late-time spectral or temporal changes that could result from a jet break but note that any lateral structure could significantly affect a jet break signature.
我们展示了对长持续伽马射线暴（GRB）221009A 的射电观测结果，该伽马射线暴被称为 "史上最亮伽马射线暴 "或 "BOAT"。我们的观测时间跨度为爆发后的前475天，观测频率为三个数量级，从0.15 GHz到230 GHz。通过将我们的新观测结果与文献中的观测结果相结合，我们获得了迄今为止所有GRB中最详细的射电数据集，我们利用这些数据集来探索余辉的光谱和时间演化。通过测试一系列现象学模型，我们发现三个独立的同步加速器成分最能解释余辉。高时间和光谱分辨率使我们得出结论，标准的分析余辉模型无法解释观测到的 GRB 221009A 的演变。我们探讨了观测结果与模型之间差异最显著的地方，并将我们的发现与迄今为止研究最深入的GRB射电余辉结合起来。我们的观测结果可以通过三个同步辐射发射区得到最好的解释，我们将其解释为一个正向冲击、一个反向冲击和一个可能来自茧或更大范围外流的附加冲击。最后，我们发现我们的观测结果没有显示出任何可能由喷流断裂引起的晚期光谱或时间变化的证据，但我们注意到任何横向结构都可能对喷流断裂特征产生重大影响。
{"title":"Rocking the BOAT: the ups and downs of the long-term radio light curve for GRB 221009A","authors":"L Rhodes, A J van der Horst, J S Bright, J K Leung, G E Anderson, R Fender, J F Agüí Fernandez, M Bremer, P Chandra, D Dobie, W Farah, S Giarratana, K Gourdji, D A Green, E Lenc, M J Michałowski, T Murphy, A J Nayana, A W Pollak, A Rowlinson, F Schussler, A Siemion, R L C Starling, P Scott, C C Thöne, D Titterington, A de Ugarte Postigo","doi":"10.1093/mnras/stae2050","DOIUrl":"https://doi.org/10.1093/mnras/stae2050","url":null,"abstract":"We present radio observations of the long-duration gamma-ray burst (GRB) 221009A which has become known to the community as the Brightest Of All Time or the BOAT. Our observations span the first 475 days post-burst and three orders of magnitude in observing frequency, from 0.15 to 230 GHz. By combining our new observations with those available in the literature, we have the most detailed radio data set in terms of cadence and spectral coverage of any GRB to date, which we use to explore the spectral and temporal evolution of the afterglow. By testing a series of phenomenological models, we find that three separate synchrotron components best explain the afterglow. The high temporal and spectral resolution allows us to conclude that standard analytical afterglow models are unable to explain the observed evolution of GRB 221009A. We explore where the discrepancies between the observations and the models are most significant and place our findings in the context of the most well-studied GRB radio afterglows to date. Our observations are best explained by three synchrotron emitting regions which we interpret as a forward shock, a reverse shock and an additional shock potentially from a cocoon or wider outflow. Finally, we find that our observations do not show any evidence of any late-time spectral or temporal changes that could result from a jet break but note that any lateral structure could significantly affect a jet break signature.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"108 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177546","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}
O P M Aslam, D MacTaggart, T Williams, L Fletcher, P Romano
Coronal mass ejections (CMEs) are solar eruptions that involve large-scale changes to the magnetic topology of an active region. There exists a range of models for CME onset which are based on twisted or sheared magnetic field above a polarity inversion line (PIL). We present observational evidence that topological changes at PILs, in the photosphere, form a key part of CME onset, as implied by many models. In particular, we study the onset of 30 CMEs and investigate topological changes in the photosphere by calculating the magnetic winding flux, using the ARTop code. By matching the times and locations of winding signatures with CME observations produced by the ALMANAC code, we confirm that these signatures are indeed associated with CMEs. Therefore, as well as presenting evidence that changes in magnetic topology at the photosphere are a common signature of CME onset, our approach also allows for the finding of the source location of a CME within an active region.
{"title":"Photospheric signatures of CME onset","authors":"O P M Aslam, D MacTaggart, T Williams, L Fletcher, P Romano","doi":"10.1093/mnras/stae2110","DOIUrl":"https://doi.org/10.1093/mnras/stae2110","url":null,"abstract":"Coronal mass ejections (CMEs) are solar eruptions that involve large-scale changes to the magnetic topology of an active region. There exists a range of models for CME onset which are based on twisted or sheared magnetic field above a polarity inversion line (PIL). We present observational evidence that topological changes at PILs, in the photosphere, form a key part of CME onset, as implied by many models. In particular, we study the onset of 30 CMEs and investigate topological changes in the photosphere by calculating the magnetic winding flux, using the ARTop code. By matching the times and locations of winding signatures with CME observations produced by the ALMANAC code, we confirm that these signatures are indeed associated with CMEs. Therefore, as well as presenting evidence that changes in magnetic topology at the photosphere are a common signature of CME onset, our approach also allows for the finding of the source location of a CME within an active region.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"64 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177548","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}
Shikhar Mittal, Girish Kulkarni, Dominic Anstey, Eloy de Lera Acedo
Contribution of resolved and unresolved extragalactic point sources to the low-frequency sky spectrum is a potentially non-negligible part of the astrophysical foregrounds for cosmic dawn 21-cm experiments. The clustering of such point sources on the sky, combined with the frequency-dependence of the antenna beam, can also make this contribution chromatic. By combining low-frequency measurements of the luminosity function and the angular correlation function of extragalactic point sources, we develop a model for the contribution of these sources to the low-frequency sky spectrum. Using this model, we find that the contribution of sources with flux density >10−6 Jy to the sky-averaged spectrum is smooth and of the order of a few kelvins at 50–200 MHz. We combine this model with measurements of the galactic foreground spectrum and weigh the resultant sky by the beam directivity of the conical log-spiral antenna planned as part of the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) project. We find that the contribution of point sources to the resultant spectrum is $sim 0.4%$ of the total foregrounds, but still larger by at least an order of magnitude than the standard predictions for the cosmological 21-cm signal. As a result, not accounting for the point-source contribution leads to a systematic bias in 21-cm signal recovery. We show, however, that in the REACH case, this reconstruction bias can be removed by modelling the point-source contribution as a power law with a running spectral index. We make our code publicly available as a Python package labelled epspy.
{"title":"Impact of extragalactic point sources on the low-frequency sky spectrum and cosmic dawn global 21-cm measurements","authors":"Shikhar Mittal, Girish Kulkarni, Dominic Anstey, Eloy de Lera Acedo","doi":"10.1093/mnras/stae2111","DOIUrl":"https://doi.org/10.1093/mnras/stae2111","url":null,"abstract":"Contribution of resolved and unresolved extragalactic point sources to the low-frequency sky spectrum is a potentially non-negligible part of the astrophysical foregrounds for cosmic dawn 21-cm experiments. The clustering of such point sources on the sky, combined with the frequency-dependence of the antenna beam, can also make this contribution chromatic. By combining low-frequency measurements of the luminosity function and the angular correlation function of extragalactic point sources, we develop a model for the contribution of these sources to the low-frequency sky spectrum. Using this model, we find that the contribution of sources with flux density >10−6 Jy to the sky-averaged spectrum is smooth and of the order of a few kelvins at 50–200 MHz. We combine this model with measurements of the galactic foreground spectrum and weigh the resultant sky by the beam directivity of the conical log-spiral antenna planned as part of the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH) project. We find that the contribution of point sources to the resultant spectrum is $sim 0.4%$ of the total foregrounds, but still larger by at least an order of magnitude than the standard predictions for the cosmological 21-cm signal. As a result, not accounting for the point-source contribution leads to a systematic bias in 21-cm signal recovery. We show, however, that in the REACH case, this reconstruction bias can be removed by modelling the point-source contribution as a power law with a running spectral index. We make our code publicly available as a Python package labelled epspy.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"43 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177640","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}
Weiguang Cui, Fred Jennings, Romeel Dave, Arif Babul, Ghassem Gozaliasl
Galaxy groups contain the majority of bound mass with a significant portion of baryons due to the combination of halo mass and abundance (Cui 2024). Hence they serve as a crucial missing piece in the puzzle of galaxy formation and the evolution of large-scale structures in the Universe. In observations, mass-complete group catalogues are normally derived from galaxy redshift surveys detected through various three-dimensional group-finding algorithms. Confirming the reality of such groups, particularly in the X-rays, is critical for ensuring robust studies of galaxy evolution in these environments. Recent works have reported numerous optical groups that are X-ray undetected (see, e.g. Popesso et al. 2024), sparking debates regarding the reasons for the unexpectedly low hot gas fraction in galaxy groups. To address this issue, we utilise zoomed-in simulations of galaxy groups from the novel Hyenas project to explore the range of hot gas fractions within galaxy groups and investigate the intrinsic factors behind the observed variability in X-ray emission. We find that the halo formation time can play a critical role – we see that groups in halos that formed earlier exhibit up to an order of magnitude brighter X-ray luminosities compared to those formed later. This suggests that undetected X-ray groups are preferentially late-formed halos and highlights the connection between gas fraction and halo formation time in galaxy groups. Accounting for these biases in galaxy group identification is essential for advancing our understanding of galaxy formation and achieving precision in cosmological studies.
星系团包含了大部分的束缚质量，由于光环质量和丰度的共同作用，还包含了相当一部分重子（Cui 2024）。因此，它们是星系形成和宇宙大尺度结构演化之谜中缺失的重要一环。在观测中，质量完整的星系群目录通常是通过各种三维星系群寻找算法从星系红移巡天中探测到的。确认这些星系群的真实性，特别是在X射线中，对于确保在这些环境中对星系演化进行有力的研究至关重要。最近的研究报告了许多未被X射线探测到的光学星系群（参见Popesso等人，2024年），引发了关于星系群中热气体比例出乎意料地低的原因的争论。为了解决这个问题，我们利用新颖的 "海纳斯"（Hyenas）项目中的星系群放大模拟来探索星系群中热气体比例的范围，并研究观测到的 X 射线辐射变化背后的内在因素。我们发现星系晕的形成时间起着至关重要的作用--我们发现星系晕中形成较早的星系群的X射线亮度要比形成较晚的星系群亮一个数量级。这表明，未被发现的X射线星系群更倾向于形成较晚的光环，并突出了星系群中气体组分和光环形成时间之间的联系。在星系群识别中考虑这些偏差，对于推进我们对星系形成的理解和实现宇宙学研究的精确性是至关重要的。
{"title":"The HYENAS project: a prediction for the X-ray undetected galaxy groups","authors":"Weiguang Cui, Fred Jennings, Romeel Dave, Arif Babul, Ghassem Gozaliasl","doi":"10.1093/mnras/stae2115","DOIUrl":"https://doi.org/10.1093/mnras/stae2115","url":null,"abstract":"Galaxy groups contain the majority of bound mass with a significant portion of baryons due to the combination of halo mass and abundance (Cui 2024). Hence they serve as a crucial missing piece in the puzzle of galaxy formation and the evolution of large-scale structures in the Universe. In observations, mass-complete group catalogues are normally derived from galaxy redshift surveys detected through various three-dimensional group-finding algorithms. Confirming the reality of such groups, particularly in the X-rays, is critical for ensuring robust studies of galaxy evolution in these environments. Recent works have reported numerous optical groups that are X-ray undetected (see, e.g. Popesso et al. 2024), sparking debates regarding the reasons for the unexpectedly low hot gas fraction in galaxy groups. To address this issue, we utilise zoomed-in simulations of galaxy groups from the novel Hyenas project to explore the range of hot gas fractions within galaxy groups and investigate the intrinsic factors behind the observed variability in X-ray emission. We find that the halo formation time can play a critical role – we see that groups in halos that formed earlier exhibit up to an order of magnitude brighter X-ray luminosities compared to those formed later. This suggests that undetected X-ray groups are preferentially late-formed halos and highlights the connection between gas fraction and halo formation time in galaxy groups. Accounting for these biases in galaxy group identification is essential for advancing our understanding of galaxy formation and achieving precision in cosmological studies.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"138 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177643","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 large-scale astronomical surveys, traditional supernova detection pipelines rely on complex and relatively inefficient image differencing techniques. This paper proposes an end-to-end deep-learning supernova detection network, the Real-Time SuperNova DEtection TRansformer (RT-SNDETR). This network partially replaces traditional pipelines by integrating image differencing, source detection, and Real-bogus classification, achieving a speed 51.49 times that of the fastest image differencing method, SFFT. Additionally, it remains competitive with methods like YOLO v8, offering a well-balanced trade-off between speed and accuracy. Experimental results highlight RT-SNDETR’s superior performance, with an average precision(AP) of 96.30% on synthetic samples and 76.60% on real supernova samples. It significantly outperforms other detection networks, including RT-DETR (+5.6% AP on synthetic/+5.1% AP on real samples) and Cascade R-CNN (+8.9% AP on synthetic/+28.6% AP on real samples). The incorporation of CycleGAN-based data generation methods plays a significant role in enhancing RT-SNDETR’s performance. These methods simulate realistic PSF variations, enabling the object detection network to learn more robust features and improving its generalization to real supernovae data. Additionally, by integrating unsupervised domain adaptation techniques, RT-SNDETR achieves an AP of 81.70% on real SDSS supernova survey samples. This study demonstrates RT-SNDETR’s potential to significantly enhance both the speed and accuracy of supernova detection, making it a highly effective solution for large-scale astronomical surveys.
{"title":"RT-SNDETR: Real-time Supernova Detection via End-to-End Image Transformers","authors":"Zhi-Ren Pan, Bo Qiu, Guang-Wei Li","doi":"10.1093/mnras/stae2107","DOIUrl":"https://doi.org/10.1093/mnras/stae2107","url":null,"abstract":"In large-scale astronomical surveys, traditional supernova detection pipelines rely on complex and relatively inefficient image differencing techniques. This paper proposes an end-to-end deep-learning supernova detection network, the Real-Time SuperNova DEtection TRansformer (RT-SNDETR). This network partially replaces traditional pipelines by integrating image differencing, source detection, and Real-bogus classification, achieving a speed 51.49 times that of the fastest image differencing method, SFFT. Additionally, it remains competitive with methods like YOLO v8, offering a well-balanced trade-off between speed and accuracy. Experimental results highlight RT-SNDETR’s superior performance, with an average precision(AP) of 96.30% on synthetic samples and 76.60% on real supernova samples. It significantly outperforms other detection networks, including RT-DETR (+5.6% AP on synthetic/+5.1% AP on real samples) and Cascade R-CNN (+8.9% AP on synthetic/+28.6% AP on real samples). The incorporation of CycleGAN-based data generation methods plays a significant role in enhancing RT-SNDETR’s performance. These methods simulate realistic PSF variations, enabling the object detection network to learn more robust features and improving its generalization to real supernovae data. Additionally, by integrating unsupervised domain adaptation techniques, RT-SNDETR achieves an AP of 81.70% on real SDSS supernova survey samples. This study demonstrates RT-SNDETR’s potential to significantly enhance both the speed and accuracy of supernova detection, making it a highly effective solution for large-scale astronomical surveys.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"16 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177550","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}
The correction map method means extended phase-space algorithm with correction map. In our research, we have developed a correction map method, specifically the dissipated correction map method with trapezoidal rule, for numerical simulations of gravitational waves from spinning compact binary systems. This new correction map method, denoted as $CM3$, has shown remarkable performance in various simulation results, such as phase-space distance, dissipated energy error, and gravitational waveform, closely resembling the high-order precision implicit Gaussian algorithm. When compared with the previously used mid-point map which is denoted as $C_2$, the $CM3$ consistently exhibits a closer alignment with the highly accurate Gaussian algorithm in waveform evolution and orbital trajectory analysis. Through detailed comparisons and analyses, it is evident that $CM3$ outperforms other algorithms, including $CM2$ and $C_2$ mentioned in this paper, in terms of accuracy and precision in simulating spinning compact binary systems. The incorporation of the trapezoidal rule and the optimization with a scale factor $gamma$ have significantly enhanced the performance of $CM3$, making it a promising method for future numerical simulations in astrophysics. With the groundbreaking detection of gravitational waves by the LIGO/VIRGO collaboration, interest in this research domain has soared. Our work contributes valuable insights for the application of matched filtering techniques in the analysis of gravitational wave signals, enhancing the precision and reliability of these detection.
{"title":"Dissipated correction map method with trapezoidal rule for the simulations of gravitational waves from spinning compact binary","authors":"Junjie Luo, Hong-Hao Zhang, Weipeng Lin","doi":"10.1093/mnras/stae1997","DOIUrl":"https://doi.org/10.1093/mnras/stae1997","url":null,"abstract":"The correction map method means extended phase-space algorithm with correction map. In our research, we have developed a correction map method, specifically the dissipated correction map method with trapezoidal rule, for numerical simulations of gravitational waves from spinning compact binary systems. This new correction map method, denoted as $CM3$, has shown remarkable performance in various simulation results, such as phase-space distance, dissipated energy error, and gravitational waveform, closely resembling the high-order precision implicit Gaussian algorithm. When compared with the previously used mid-point map which is denoted as $C_2$, the $CM3$ consistently exhibits a closer alignment with the highly accurate Gaussian algorithm in waveform evolution and orbital trajectory analysis. Through detailed comparisons and analyses, it is evident that $CM3$ outperforms other algorithms, including $CM2$ and $C_2$ mentioned in this paper, in terms of accuracy and precision in simulating spinning compact binary systems. The incorporation of the trapezoidal rule and the optimization with a scale factor $gamma$ have significantly enhanced the performance of $CM3$, making it a promising method for future numerical simulations in astrophysics. With the groundbreaking detection of gravitational waves by the LIGO/VIRGO collaboration, interest in this research domain has soared. Our work contributes valuable insights for the application of matched filtering techniques in the analysis of gravitational wave signals, enhancing the precision and reliability of these detection.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"10 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177551","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}
Giulia Santucci, Claudia Del P Lagos, Katherine E Harborne, Caro Derkenne, Adriano Poci, Sabine Thater, Richard M McDermid, J Trevor Mendel, Emily Wisnioski, Scott M Croom, Anna Ferré-Mateu, Eric G M Muller, Jesse van de Sande, Gauri Sharma, Sarah M Sweet, Takafumi Tsukui, Lucas M Valenzuela, Glenn van de Ven, Tayyaba Zafar
Schwarzschild dynamical models are now regularly employed in large surveys of galaxies in the local and distant Universe to derive information on galaxies’ intrinsic properties such as their orbital structure and their (dark matter and stellar) mass distribution. Comparing the internal orbital structures and mass distributions of galaxies in the distant Universe with simulations is key to understanding what physical processes are responsible for shaping galaxy properties. However it is first crucial to understand whether observationally derived properties are directly comparable with intrinsic ones in simulations. To assess this, we build Schwarzschild dynamical models for MUSE-like IFS cubes (constructed to be like those obtained by the MAGPI survey) of 75 galaxies at z ∼ 0.3 from the Eagle simulations. We compare the true particle-derived properties with the galaxies’ model-derived properties. In general, we find that the models can recover the true galaxy properties qualitatively well, with the exception of the enclosed dark matter, where we find a median offset of 48%, which is due to the assumed NFW profile not being able to reproduce the dark matter distribution in the inner region of the galaxies. We then compare our model-derived properties with Schwarzschild models-derived properties of observed MAGPI galaxies and find good agreement between MAGPI and Eagle: the majority of our galaxies (57%) have non-oblate shapes within 1 effective radius. More triaxial galaxies show higher fractions of hot orbits in their inner regions and tend to be more radially anisotropic.
{"title":"The MAGPI Survey: Orbital distributions, intrinsic shapes, and mass profiles for MAGPI-like Eagle galaxies using Schwarzschild dynamical models","authors":"Giulia Santucci, Claudia Del P Lagos, Katherine E Harborne, Caro Derkenne, Adriano Poci, Sabine Thater, Richard M McDermid, J Trevor Mendel, Emily Wisnioski, Scott M Croom, Anna Ferré-Mateu, Eric G M Muller, Jesse van de Sande, Gauri Sharma, Sarah M Sweet, Takafumi Tsukui, Lucas M Valenzuela, Glenn van de Ven, Tayyaba Zafar","doi":"10.1093/mnras/stae2114","DOIUrl":"https://doi.org/10.1093/mnras/stae2114","url":null,"abstract":"Schwarzschild dynamical models are now regularly employed in large surveys of galaxies in the local and distant Universe to derive information on galaxies’ intrinsic properties such as their orbital structure and their (dark matter and stellar) mass distribution. Comparing the internal orbital structures and mass distributions of galaxies in the distant Universe with simulations is key to understanding what physical processes are responsible for shaping galaxy properties. However it is first crucial to understand whether observationally derived properties are directly comparable with intrinsic ones in simulations. To assess this, we build Schwarzschild dynamical models for MUSE-like IFS cubes (constructed to be like those obtained by the MAGPI survey) of 75 galaxies at z ∼ 0.3 from the Eagle simulations. We compare the true particle-derived properties with the galaxies’ model-derived properties. In general, we find that the models can recover the true galaxy properties qualitatively well, with the exception of the enclosed dark matter, where we find a median offset of 48%, which is due to the assumed NFW profile not being able to reproduce the dark matter distribution in the inner region of the galaxies. We then compare our model-derived properties with Schwarzschild models-derived properties of observed MAGPI galaxies and find good agreement between MAGPI and Eagle: the majority of our galaxies (57%) have non-oblate shapes within 1 effective radius. More triaxial galaxies show higher fractions of hot orbits in their inner regions and tend to be more radially anisotropic.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"17 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177549","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}
Lei Wang, Xiaoming Zhang, Chunhai Bai, Haiwen Xie, Juan Li, Jiayi Ge, Jianfeng Wang, Xianqun Zeng, Jiantao Sun, Xiaojun Jiang
Optically observing and monitoring moving objects, both natural and artificial, is important to human space security. Non-sidereal tracking can improve the system’s limiting magnitude for moving objects, which benefits the surveillance. However, images with non-sidereal tracking include complex background, as well as objects with different brightness and moving mode, posing a significant challenge for accurate multi-object detection in such images, especially in wide field of view (WFOV) telescope images. To achieve a higher detection precision in a higher speed, we proposed a novel object detection method, which combines the source feature extraction and the neural network. First, our method extracts object features from optical images such as centroid, shape, and flux. Then it conducts a naive labeling based on those features to distinguish moving objects from stars. After balancing the labeled data, we employ it to train a neural network aimed at creating a classification model for point-like and streak-like objects. Ultimately, based on the neural network model’s classification outcomes, moving objects whose motion modes consistent with the tracked objects are detected via track association, while objects with different motion modes are detected using morphological statistics. The validation, based on the space objects images captured in target tracking mode with the 1-meter telescope at Nanshan, Xinjiang Astronomical Observatory, demonstrates that our method achieves 94.72% detection accuracy with merely 5.02% false alarm rate, and a processing time of 0.66s per frame. Consequently, our method can rapidly and accurately detect objects with different motion modes from wide-field images with non-sidereal tracking.
{"title":"Rapid automatic multiple moving objects detection method based on feature extraction from images with non-sidereal tracking","authors":"Lei Wang, Xiaoming Zhang, Chunhai Bai, Haiwen Xie, Juan Li, Jiayi Ge, Jianfeng Wang, Xianqun Zeng, Jiantao Sun, Xiaojun Jiang","doi":"10.1093/mnras/stae2073","DOIUrl":"https://doi.org/10.1093/mnras/stae2073","url":null,"abstract":"Optically observing and monitoring moving objects, both natural and artificial, is important to human space security. Non-sidereal tracking can improve the system’s limiting magnitude for moving objects, which benefits the surveillance. However, images with non-sidereal tracking include complex background, as well as objects with different brightness and moving mode, posing a significant challenge for accurate multi-object detection in such images, especially in wide field of view (WFOV) telescope images. To achieve a higher detection precision in a higher speed, we proposed a novel object detection method, which combines the source feature extraction and the neural network. First, our method extracts object features from optical images such as centroid, shape, and flux. Then it conducts a naive labeling based on those features to distinguish moving objects from stars. After balancing the labeled data, we employ it to train a neural network aimed at creating a classification model for point-like and streak-like objects. Ultimately, based on the neural network model’s classification outcomes, moving objects whose motion modes consistent with the tracked objects are detected via track association, while objects with different motion modes are detected using morphological statistics. The validation, based on the space objects images captured in target tracking mode with the 1-meter telescope at Nanshan, Xinjiang Astronomical Observatory, demonstrates that our method achieves 94.72% detection accuracy with merely 5.02% false alarm rate, and a processing time of 0.66s per frame. Consequently, our method can rapidly and accurately detect objects with different motion modes from wide-field images with non-sidereal tracking.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"9 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177553","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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