Pub Date : 2024-04-02DOI: 10.1088/1538-3873/ad2c95
Nathan W. Galliher, Thomas Procter, Nicholas M. Law, Hank Corbett, Ward S. Howard, Alan Vasquez Soto, Ramses Gonzalez, Lawrence Machia, Jonathan Carney, William J. Marshall
ArgusSpec is a prototype autonomous spectroscopic follow-up instrument designed to characterize flares detected by the Argus Pathfinder telescope array by taking short exposure (30 s) broadband spectra (370–750 nm) at low resolutions (R ∼ 150 at 500 nm). The instrument is built from consumer off-the-shelf astronomical equipment, assembled inside a shipping container, and deployed alongside the Argus Pathfinder at a dark sky observing site in Western North Carolina. In this paper, we describe the hardware design, system electronics, custom control software suite, automated target acquisition procedure, and data reduction pipeline. We present initial on-sky test data used to evaluate system performance and show a series of spectra taken of a small flare from AD Leonis. The $35k prototype ArgusSpec was designed, built, and deployed in under a year, largely from existing parts, and has been operating on-sky since 2023 March. With current hardware and software, the system is capable of receiving an observation, slewing, performing autonomous slit acquisition, and beginning data acquisition within an average of 32 s. With Argus Pathfinder’s 1 s cadence survey reporting alerts of rising sources within 2 s of onset, ArgusSpec can reach new targets well within a minute of the start of the event. As built, ArgusSpec can observe targets down to a 20σ limiting magnitude of mV ≈ 13 at 30 s cadence with an optical resolution of R ∼ 150 (at 500 nm). With automated rapid acquisition demonstrated, later hardware upgrades will be based on a clean-sheet optical design, solving many issues in the current system, significantly improving the limiting magnitude, and potentially enabling deep spectroscopy by the coaddition of data from an array of ArgusSpec systems. The primary science driver behind ArgusSpec is the characterization of the blackbody evolution of flares from nearby M-dwarfs. Large flares emitted by these stars could have significant impacts on the potential habitability of any orbiting exoplanets, but our current understanding of these events is in large part built on observations from a handful of active stars. ArgusSpec will characterize large numbers of flares from across the night sky, building a spectroscopic library of the most extreme events from a wide variety of stellar masses and ages.
ArgusSpec 是一个自主光谱跟踪仪器原型，旨在通过以低分辨率（500 nm 处 R ∼ 150）拍摄短时间曝光（30 秒）宽带光谱（370-750 nm）来描述 Argus 探路者望远镜阵列探测到的耀斑。该仪器使用现成的天文设备，组装在一个集装箱内，与阿格斯探路者一起部署在北卡罗来纳州西部的一个暗天观测点。在本文中，我们将介绍硬件设计、系统电子设备、定制控制软件套件、自动目标获取程序和数据缩减管道。我们介绍了用于评估系统性能的初始星空测试数据，并展示了从 AD Leonis 拍摄的一系列小型耀斑光谱。耗资 3.5 万美元的原型 ArgusSpec 在不到一年的时间内完成了设计、制造和部署，主要是利用现有部件，自 2023 年 3 月以来一直在星上运行。由于 Argus Pathfinder 的 1 秒周期巡天会在开始后 2 秒内报告上升源警报，ArgusSpec 可以在事件开始后一分钟内到达新目标。目前，ArgusSpec 能以 30 秒的频率观测到 mV ≈ 13 的 20σ 极限量级目标，光学分辨率为 R ∼ 150（500 纳米）。在演示了自动快速采集之后，以后的硬件升级将以简洁的光学设计为基础，解决目前系统中的许多问题，显著提高极限量级，并有可能通过对 ArgusSpec 系统阵列中的数据进行叠加来实现深度光谱分析。ArgusSpec 背后的主要科学驱动力是鉴定附近 M 型矮星耀斑的黑体演化。这些恒星发射的大型耀斑可能会对任何环绕系外行星的潜在宜居性产生重大影响，但我们目前对这些事件的了解在很大程度上是建立在对少数活跃恒星的观测基础上的。ArgusSpec 将对夜空中的大量耀斑进行定性分析，建立一个包含各种质量和年龄恒星的最极端事件的光谱库。
{"title":"The ArgusSpec Prototype: Autonomous Spectroscopic Follow-up of Flares Detected by Large Array Telescopes","authors":"Nathan W. Galliher, Thomas Procter, Nicholas M. Law, Hank Corbett, Ward S. Howard, Alan Vasquez Soto, Ramses Gonzalez, Lawrence Machia, Jonathan Carney, William J. Marshall","doi":"10.1088/1538-3873/ad2c95","DOIUrl":"https://doi.org/10.1088/1538-3873/ad2c95","url":null,"abstract":"ArgusSpec is a prototype autonomous spectroscopic follow-up instrument designed to characterize flares detected by the Argus Pathfinder telescope array by taking short exposure (30 s) broadband spectra (370–750 nm) at low resolutions (<italic toggle=\"yes\">R</italic> ∼ 150 at 500 nm). The instrument is built from consumer off-the-shelf astronomical equipment, assembled inside a shipping container, and deployed alongside the Argus Pathfinder at a dark sky observing site in Western North Carolina. In this paper, we describe the hardware design, system electronics, custom control software suite, automated target acquisition procedure, and data reduction pipeline. We present initial on-sky test data used to evaluate system performance and show a series of spectra taken of a small flare from AD Leonis. The $35k prototype ArgusSpec was designed, built, and deployed in under a year, largely from existing parts, and has been operating on-sky since 2023 March. With current hardware and software, the system is capable of receiving an observation, slewing, performing autonomous slit acquisition, and beginning data acquisition within an average of 32 s. With Argus Pathfinder’s 1 s cadence survey reporting alerts of rising sources within 2 s of onset, ArgusSpec can reach new targets well within a minute of the start of the event. As built, ArgusSpec can observe targets down to a 20<italic toggle=\"yes\">σ</italic> limiting magnitude of <italic toggle=\"yes\">m</italic>\u0000<sub>\u0000<italic toggle=\"yes\">V</italic>\u0000</sub> ≈ 13 at 30 s cadence with an optical resolution of <italic toggle=\"yes\">R</italic> ∼ 150 (at 500 nm). With automated rapid acquisition demonstrated, later hardware upgrades will be based on a clean-sheet optical design, solving many issues in the current system, significantly improving the limiting magnitude, and potentially enabling deep spectroscopy by the coaddition of data from an array of ArgusSpec systems. The primary science driver behind ArgusSpec is the characterization of the blackbody evolution of flares from nearby M-dwarfs. Large flares emitted by these stars could have significant impacts on the potential habitability of any orbiting exoplanets, but our current understanding of these events is in large part built on observations from a handful of active stars. ArgusSpec will characterize large numbers of flares from across the night sky, building a spectroscopic library of the most extreme events from a wide variety of stellar masses and ages.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140580924","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 darkness of the sky is a critical parameter for assessing the suitability of an astronomical site. Among various sources of light pollution, urban lights pose the most significant threat to ground-based optical astronomical and planetary observations. Quantitatively assessing the impact of urban lights with varying scales and fluxes is indispensable for selecting an ideal optical observation site. In order to quantitatively assess the changes in Night Sky Brightness (NSB) relative to the distance from urban areas and to establish a foundation for safeguarding the light environment at the newly developed Lenghu astronomical site on the Tibetan Plateau, we employed both a Sky Quality Meter and a pre-calibrated smartphone. These instruments were used to measure the NSB in the vicinity of two cities, Da Qaidam and Delingha, which vary in size and radiant flux, on the Tibetan Plateau. The findings indicate that the NSB around both cities decreases significantly as the distance from the city center increases, although the rate of decrease varies between the two locations. This decline can be effectively modeled using an exponential decay function. Notably, the influence of city lights on NSB becomes negligible at distances exceeding 30 km from Da Qaidam, while for Delingha, this distance extends to 50 km due to its larger city size and higher total radiant flux. The methodologies and results presented in this paper offer valuable insights for the selection of astronomical observation sites and the development of light pollution management policies.
{"title":"Assessing the Influence of Urban Lights on Night Sky Brightness with a Smartphone","authors":"Yingqiang Wang, Yong Zhao, Weijia Sun, Fan Yang, Licai Deng, Fei He, Zhaojin Rong, Yong Wei","doi":"10.1088/1538-3873/ad332a","DOIUrl":"https://doi.org/10.1088/1538-3873/ad332a","url":null,"abstract":"The darkness of the sky is a critical parameter for assessing the suitability of an astronomical site. Among various sources of light pollution, urban lights pose the most significant threat to ground-based optical astronomical and planetary observations. Quantitatively assessing the impact of urban lights with varying scales and fluxes is indispensable for selecting an ideal optical observation site. In order to quantitatively assess the changes in Night Sky Brightness (NSB) relative to the distance from urban areas and to establish a foundation for safeguarding the light environment at the newly developed Lenghu astronomical site on the Tibetan Plateau, we employed both a Sky Quality Meter and a pre-calibrated smartphone. These instruments were used to measure the NSB in the vicinity of two cities, Da Qaidam and Delingha, which vary in size and radiant flux, on the Tibetan Plateau. The findings indicate that the NSB around both cities decreases significantly as the distance from the city center increases, although the rate of decrease varies between the two locations. This decline can be effectively modeled using an exponential decay function. Notably, the influence of city lights on NSB becomes negligible at distances exceeding 30 km from Da Qaidam, while for Delingha, this distance extends to 50 km due to its larger city size and higher total radiant flux. The methodologies and results presented in this paper offer valuable insights for the selection of astronomical observation sites and the development of light pollution management policies.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140581000","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}
Pub Date : 2024-04-01DOI: 10.1088/1538-3873/ad3b39
Chu Wing So, Edwin Lok-hei Yuen, Edgar Heung Fat Leung, J. Pun
Here we present a proof of concept for the application of the Variance of Laplacian (VL) method in quantifying the sharpness of optical solar images. We conducted a comprehensive study using over 65,000 individual solar images acquired on more than 160 days. Each image underwent processing using a VL image processing algorithm, which assigns a “score” based on the sharpness of the solar disk’s edges. We studied the scores obtained from images acquired at different conditions. Our findings demonstrate that the sharpness of the images exhibits daily trends that are closely linked to the altitude of the Sun at the observation site. We observed a significant degradation in image quality only below a certain altitude threshold. Furthermore, we compared airmass formulae from the literature with our sharpness observations and concluded that the degradation could be modeled as an Image Sharpness Function (ISF), which exhibits similarities to airmass variations. In addition to assessing image quality, our method has the potential to evaluate the optical atmospheric conditions during daytime observations. Moreover, this technique can be easily and cost-effectively applied to archival or real-time images of other celestial bodies, such as the Moon, bright planets and defocused stars. Given that ISF is unique to each location and sensitive to sky conditions, the development of an ISF is not only beneficial for routine observation preparation but also essential for long-term site monitoring.
{"title":"Solar Image Quality Assessment: A Proof of Concept Using Variance of Laplacian Method and its Application to Optical Atmospheric Condition Monitoring","authors":"Chu Wing So, Edwin Lok-hei Yuen, Edgar Heung Fat Leung, J. Pun","doi":"10.1088/1538-3873/ad3b39","DOIUrl":"https://doi.org/10.1088/1538-3873/ad3b39","url":null,"abstract":"\u0000 Here we present a proof of concept for the application of the Variance of Laplacian (VL) method in quantifying the sharpness of optical solar images. We conducted a comprehensive study using over 65,000 individual solar images acquired on more than 160 days. Each image underwent processing using a VL image processing algorithm, which assigns a “score” based on the sharpness of the solar disk’s edges. We studied the scores obtained from images acquired at different conditions. Our findings demonstrate that the sharpness of the images exhibits daily trends that are closely linked to the altitude of the Sun at the observation site. We observed a significant degradation in image quality only below a certain altitude threshold. Furthermore, we compared airmass formulae from the literature with our sharpness observations and concluded that the degradation could be modeled as an Image Sharpness Function (ISF), which exhibits similarities to airmass variations. In addition to assessing image quality, our method has the potential to evaluate the optical atmospheric conditions during daytime observations. Moreover, this technique can be easily and cost-effectively applied to archival or real-time images of other celestial bodies, such as the Moon, bright planets and defocused stars. Given that ISF is unique to each location and sensitive to sky conditions, the development of an ISF is not only beneficial for routine observation preparation but also essential for long-term site monitoring.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140778339","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}
Pub Date : 2024-04-01DOI: 10.1088/1538-3873/ad3aa2
Alex Broughton, Y. Utsumi, A. A. Plazas Malagón, Chris Waters, Craig Lage, Adam Snyder, Andrew Rasmussen, Stuart Marshall, Jim Chiang, Simona Murgia, A. Roodman
Thick, fully depleted charge-coupled devices are known to exhibit nonlinear behavior at high signal levels due to the dynamic behavior of charges collecting in the potential wells of pixels, called the brighter-fatter effect (BFE). The effect results in distorted images of bright calibration stars, creating a flux-dependent point-spread function that if left unmitigated, could make up a large fraction of the error budget in Stage IV weak-lensing (WL) surveys such as the Legacy Survey of Space and Time (LSST). In this paper, we analyze image measurements of flat fields and artificial stars taken at different illumination levels with the LSST Camera (LSSTCam) at SLAC National Accelerator Laboratory in order to quantify this effect in the LSSTCam before and after a previously introduced correction technique. We observe that the BFE evolves anisotropically as a function of flux due to higher-order BFEs, which violates the fundamental assumption of this correction method. We then introduce a new method based on a physically motivated model to account for these higher-order terms in the correction, and then we test the modified correction on both data sets. We find that the new method corrects the effect in flat fields better than it corrects the effect in artificial stars, which we suggest is the result of sub-pixel physics not included in this correction model. We use these results to define a new metric for the full-well capacity of our sensors and advise image processing strategies to further limit the impact of the effect on LSST WL science pathways.
{"title":"Mitigation of the Brighter-fatter Effect in the LSST Camera","authors":"Alex Broughton, Y. Utsumi, A. A. Plazas Malagón, Chris Waters, Craig Lage, Adam Snyder, Andrew Rasmussen, Stuart Marshall, Jim Chiang, Simona Murgia, A. Roodman","doi":"10.1088/1538-3873/ad3aa2","DOIUrl":"https://doi.org/10.1088/1538-3873/ad3aa2","url":null,"abstract":"\u0000 Thick, fully depleted charge-coupled devices are known to exhibit nonlinear behavior at high signal levels due to the dynamic behavior of charges collecting in the potential wells of pixels, called the brighter-fatter effect (BFE). The effect results in distorted images of bright calibration stars, creating a flux-dependent point-spread function that if left unmitigated, could make up a large fraction of the error budget in Stage IV weak-lensing (WL) surveys such as the Legacy Survey of Space and Time (LSST). In this paper, we analyze image measurements of flat fields and artificial stars taken at different illumination levels with the LSST Camera (LSSTCam) at SLAC National Accelerator Laboratory in order to quantify this effect in the LSSTCam before and after a previously introduced correction technique. We observe that the BFE evolves anisotropically as a function of flux due to higher-order BFEs, which violates the fundamental assumption of this correction method. We then introduce a new method based on a physically motivated model to account for these higher-order terms in the correction, and then we test the modified correction on both data sets. We find that the new method corrects the effect in flat fields better than it corrects the effect in artificial stars, which we suggest is the result of sub-pixel physics not included in this correction model. We use these results to define a new metric for the full-well capacity of our sensors and advise image processing strategies to further limit the impact of the effect on LSST WL science pathways.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140791476","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}
Pub Date : 2024-03-27DOI: 10.1088/1538-3873/ad31c9
Pablo López
It is usually assumed that the angular momentum (AM) of dark matter halos arises during the linear stages of structure formation, as a consequence of the coupling between the proto-haloes’ shape and the tidal field produced by their surrounding density perturbations. This approach, known as linear tidal torque theory (TTT), has been shown to make fairly good predictions about the mean evolution of both the AM amplitude and orientation up to approximately the time when the proto-haloes collapse. After this point, proto-haloes are increasingly affected by nonlinear processes that are not taken into account by the model. However, it has been seen in numerical simulations that, even at very early stages, the AM of proto-haloes is systematically reoriented toward perpendicularity with respect to the forming cosmic filaments, in contradiction with the fixed direction expected from the TTT. In this work we present a novel analytical approach that introduces an anisotropic scaling factor to the standard TTT equations, which allows the AM orientation to change in time, even during the linear regime. The amplitude and direction of this shift depend on the large scale tidal field around the forming proto-haloes. Our results significantly improve the predictions for the AM direction up to the time of protohalo collapse and, in some cases, even further in time.
通常的假设是，暗物质光环的角动量（AM）产生于结构形成的线性阶段，是原光环的形状与其周围密度扰动所产生的潮汐场之间耦合的结果。这种方法被称为线性潮汐力矩理论（TTT），已被证明可以很好地预测 AM 振幅和方向的平均演化，直至原初光环坍缩为止。在此之后，原螺旋会越来越多地受到非线性过程的影响，而这些过程并没有被模型考虑在内。然而，我们在数值模拟中发现，即使在很早的阶段，原恒星的AM方向也会系统地调整为与正在形成的宇宙丝垂直，这与TTT所预期的固定方向是矛盾的。在这项工作中，我们提出了一种新颖的分析方法，即在标准 TTT 方程中引入各向异性的缩放因子，从而使 AM 方向随时间发生变化，即使在线性状态下也是如此。这种变化的幅度和方向取决于正在形成的原海泡石周围的大尺度潮汐场。我们的结果极大地改进了对 AM 方向的预测，直至原光环坍缩之时，在某些情况下，甚至在时间上更进一步。
{"title":"Early Evolution of Spin Direction in Dark Matter Halos and the Effect of the Surrounding Large-scale Tidal Field* * Thesis work conducted at Facultad de Matemática, Astronomía, Física y Computación, Universidad Nacional de Córdoba, Córdoba, Argentina. † † PhD Thesis directed by Manuel Merchán; PhD Degree awarded 2023 July 31.","authors":"Pablo López","doi":"10.1088/1538-3873/ad31c9","DOIUrl":"https://doi.org/10.1088/1538-3873/ad31c9","url":null,"abstract":"It is usually assumed that the angular momentum (AM) of dark matter halos arises during the linear stages of structure formation, as a consequence of the coupling between the proto-haloes’ shape and the tidal field produced by their surrounding density perturbations. This approach, known as linear tidal torque theory (TTT), has been shown to make fairly good predictions about the mean evolution of both the AM amplitude and orientation up to approximately the time when the proto-haloes collapse. After this point, proto-haloes are increasingly affected by nonlinear processes that are not taken into account by the model. However, it has been seen in numerical simulations that, even at very early stages, the AM of proto-haloes is systematically reoriented toward perpendicularity with respect to the forming cosmic filaments, in contradiction with the fixed direction expected from the TTT. In this work we present a novel analytical approach that introduces an anisotropic scaling factor to the standard TTT equations, which allows the AM orientation to change in time, even during the linear regime. The amplitude and direction of this shift depend on the large scale tidal field around the forming proto-haloes. Our results significantly improve the predictions for the AM direction up to the time of protohalo collapse and, in some cases, even further in time.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314680","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}
Pub Date : 2024-03-27DOI: 10.1088/1538-3873/ad2e11
Gabriele Coppi, Simon Dicker, James E. Aguirre, Jason E. Austermann, James A. Beall, Susan E. Clark, Erin G. Cox, Mark J. Devlin, Laura M. Fissel, Nicholas Galitzki, Brandon S. Hensley, Johannes Hubmayr, Sergio Molinari, Federico Nati, Giles Novak, Eugenio Schisano, Juan D. Soler, Carole E. Tucker, Joel N. Ullom, Anna Vaskuri, Michael R. Vissers, Jordan D. Wheeler, Mario Zannoni, (The BLAST Observatory Collaboration)
Sensitive wide-field observations of polarized thermal emission from interstellar dust grains will allow astronomers to address key outstanding questions about the life cycle of matter and energy driving the formation of stars and the evolution of galaxies. Stratospheric balloon-borne telescopes can map this polarized emission at far-infrared wavelengths near the peak of the dust thermal spectrum—wavelengths that are inaccessible from the ground. In this paper we address the sensitivity achievable by a Super Pressure Balloon polarimetry mission, using as an example the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) Observatory. By launching from Wanaka, New Zealand, the BLAST Observatory can obtain a 30 days flight with excellent sky coverage—overcoming limitations of past experiments that suffered from short flight duration and/or launch sites with poor coverage of nearby star-forming regions. This proposed polarimetry mission will map large regions of the sky at sub-arcminute resolution, with simultaneous observations at 175, 250, and 350 μm, using a total of 8274 microwave kinetic inductance detectors. Here, we describe the scientific motivation for the BLAST Observatory, the proposed implementation, and the forecasting methods used to predict its sensitivity. We also compare our forecasted experiment sensitivity with other facilities.
{"title":"The BLAST Observatory: A Sensitivity Study for Far-IR Balloon-borne Polarimeters","authors":"Gabriele Coppi, Simon Dicker, James E. Aguirre, Jason E. Austermann, James A. Beall, Susan E. Clark, Erin G. Cox, Mark J. Devlin, Laura M. Fissel, Nicholas Galitzki, Brandon S. Hensley, Johannes Hubmayr, Sergio Molinari, Federico Nati, Giles Novak, Eugenio Schisano, Juan D. Soler, Carole E. Tucker, Joel N. Ullom, Anna Vaskuri, Michael R. Vissers, Jordan D. Wheeler, Mario Zannoni, (The BLAST Observatory Collaboration)","doi":"10.1088/1538-3873/ad2e11","DOIUrl":"https://doi.org/10.1088/1538-3873/ad2e11","url":null,"abstract":"Sensitive wide-field observations of polarized thermal emission from interstellar dust grains will allow astronomers to address key outstanding questions about the life cycle of matter and energy driving the formation of stars and the evolution of galaxies. Stratospheric balloon-borne telescopes can map this polarized emission at far-infrared wavelengths near the peak of the dust thermal spectrum—wavelengths that are inaccessible from the ground. In this paper we address the sensitivity achievable by a Super Pressure Balloon polarimetry mission, using as an example the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) Observatory. By launching from Wanaka, New Zealand, the BLAST Observatory can obtain a 30 days flight with excellent sky coverage—overcoming limitations of past experiments that suffered from short flight duration and/or launch sites with poor coverage of nearby star-forming regions. This proposed polarimetry mission will map large regions of the sky at sub-arcminute resolution, with simultaneous observations at 175, 250, and 350 <italic toggle=\"yes\">μ</italic>m, using a total of 8274 microwave kinetic inductance detectors. Here, we describe the scientific motivation for the BLAST Observatory, the proposed implementation, and the forecasting methods used to predict its sensitivity. We also compare our forecasted experiment sensitivity with other facilities.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314705","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}
Pub Date : 2024-03-19DOI: 10.1088/1538-3873/ad23fc
Chengxing Zhai, Michael Shao, Navtej Saini, Philip Choi, Nez Evans, Russell Trahan, Kutay Nazli, Max Zhan
Synthetic tracking (ST) has emerged as a potent technique for observing fast-moving near-Earth objects (NEOs), offering enhanced detection sensitivity and astrometric accuracy by avoiding trailing loss. This approach also empowers small telescopes to use prolonged integration times to achieve high sensitivity for NEO surveys and follow-up observations. In this study, we present the outcomes of ST observations conducted with Pomona College’s 1 m telescope at the Table Mountain Facility and JPL’s robotic telescopes at the Sierra Remote Observatory. The results showcase astrometric accuracy statistics comparable to stellar astrometry, irrespective of an object’s rate of motion, and the capability to detect faint asteroids beyond 20.5th magnitude using 11 inch telescopes. Furthermore, we detail the technical aspects of data processing, including the correction of differential chromatic refraction in the atmosphere and accurate timing for image stacking, which contribute to achieving precise astrometry. We also provide compelling examples that showcase the robustness of ST even when asteroids closely approach stars or bright satellites cause disturbances. Moreover, we illustrate the proficiency of ST in recovering NEO candidates with highly uncertain ephemerides. As a glimpse of the potential of NEO surveys utilizing small robotic telescopes with ST, we present significant statistics from our NEO survey conducted for testing purposes. These findings underscore the promise and effectiveness of ST as a powerful tool for observing fast-moving NEOs, offering valuable insights into their trajectories and characteristics. Overall, the adoption of ST stands to revolutionize fast-moving NEO observations for planetary defense and studying these celestial bodies.
合成跟踪（ST）已成为观测快速移动近地天体（NEOs）的一种有效技术，它通过避免拖尾损失提高了探测灵敏度和天体测量精度。这种方法还使小型望远镜能够利用较长的积分时间来实现近地天体巡天和跟踪观测的高灵敏度。在本研究中，我们介绍了利用波莫纳学院在桌山设施的 1 米望远镜和 JPL 在 Sierra Remote Observatory 的机器人望远镜进行 ST 观测的结果。观测结果表明，无论天体的运动速度如何，天体测量的精确度统计都可与恒星天体测量相媲美，而且使用 11 英寸望远镜还能探测到 20.5 等以上的暗小行星。此外，我们还详细介绍了数据处理技术方面的问题，包括大气层中色差折射的校正和图像叠加的精确计时，这些都有助于实现精确的天体测量。我们还提供了令人信服的示例，展示了 ST 即使在小行星接近恒星或明亮卫星造成干扰时的稳健性。此外，我们还展示了 ST 在星历表高度不确定的情况下恢复近地天体候选星的能力。作为利用带有 ST 的小型机器人望远镜进行近地天体测量的潜力一瞥，我们展示了为测试目的而进行的近地天体测量的重要统计数据。这些发现强调了 ST 作为观测快速移动近地天体的强大工具的前景和有效性，为了解近地天体的轨迹和特征提供了宝贵的信息。总之，ST 的采用将彻底改变用于行星防御和研究这些天体的快速移动近地天体观测。
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Pub Date : 2024-03-19DOI: 10.1088/1538-3873/ad2551
Mattia Libralato, Ioannis Argyriou, Dan Dicken, Macarena García Marín, Pierre Guillard, Dean C. Hines, Patrick J. Kavanagh, Sarah Kendrew, David R. Law, Alberto Noriega-Crespo, Javier Álvarez-Márquez
Astrometry is one of the main pillars of astronomy, and one of its oldest branches. Over the years, an increasing number of astrometric works by means of Hubble Space Telescope (HST) data have revolutionized our understanding of various phenomena. With the launch of JWST, it becomes almost instinctive to want to replicate or improve these results with data taken with the newest, state-of-the-art, space-based telescope. In this regard, the initial focus of the community has been on the Near-Infrared detectors on board of JWST because of their high spatial resolution. This paper begins the effort to capture and apply what has been learned from HST to the Mid-InfraRed Instrument (MIRI) of JWST by developing the tools to obtain high-precision astrometry and photometry with its imager. We describe in detail how to create accurate effective point-spread-function (ePSF) models and geometric-distortion corrections, analyze their temporal stability, and test their quality to the extent of what is currently possible with the available data in the JWST MAST archive. We show that careful data reduction provides deep insight on the performance and intricacies of the MIRI imager, and of JWST in general. In an effort to help the community devise new observing programs, we make our ePSF models and geometric-distortion corrections publicly available.
{"title":"High-precision Astrometry and Photometry with the JWST/MIRI Imager","authors":"Mattia Libralato, Ioannis Argyriou, Dan Dicken, Macarena García Marín, Pierre Guillard, Dean C. Hines, Patrick J. Kavanagh, Sarah Kendrew, David R. Law, Alberto Noriega-Crespo, Javier Álvarez-Márquez","doi":"10.1088/1538-3873/ad2551","DOIUrl":"https://doi.org/10.1088/1538-3873/ad2551","url":null,"abstract":"Astrometry is one of the main pillars of astronomy, and one of its oldest branches. Over the years, an increasing number of astrometric works by means of Hubble Space Telescope (HST) data have revolutionized our understanding of various phenomena. With the launch of JWST, it becomes almost instinctive to want to replicate or improve these results with data taken with the newest, state-of-the-art, space-based telescope. In this regard, the initial focus of the community has been on the Near-Infrared detectors on board of JWST because of their high spatial resolution. This paper begins the effort to capture and apply what has been learned from HST to the Mid-InfraRed Instrument (MIRI) of JWST by developing the tools to obtain high-precision astrometry and photometry with its imager. We describe in detail how to create accurate effective point-spread-function (ePSF) models and geometric-distortion corrections, analyze their temporal stability, and test their quality to the extent of what is currently possible with the available data in the JWST MAST archive. We show that careful data reduction provides deep insight on the performance and intricacies of the MIRI imager, and of JWST in general. In an effort to help the community devise new observing programs, we make our ePSF models and geometric-distortion corrections publicly available.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314907","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}
Pub Date : 2024-03-13DOI: 10.1088/1538-3873/ad2866
Pieter van Dokkum, Imad Pasha
Astronomical images often have regions with missing or unwanted information, such as bad pixels, bad columns, cosmic rays, masked objects, or residuals from imperfect model subtractions. In certain situations it can be essential, or preferable, to fill in these regions. Most existing methods use low order interpolations for this task. In this paper a method is described that uses the full information that is contained in the pixels just outside masked regions. These edge pixels are extrapolated inwards, using iterative median filtering. This leads to a smoothly varying spatial resolution within the filled-in regions, and ensures seamless transitions between masked pixels and good pixels. Gaps in continuous, narrow features can be reconstructed with high fidelity, even if they are large. The method is implemented in maskfill, an open-source MIT licensed Python package (https://github.com/dokkum/maskfill). Its performance is illustrated with several examples, and compared to several alternative interpolation schemes.
天文图像中经常会有信息缺失或不需要信息的区域，例如坏像素、坏柱、宇宙射线、遮挡物体或不完美的模型减法产生的残差。在某些情况下，对这些区域进行填充可能是必要的或可取的。现有的大多数方法都使用低阶插值来完成这项任务。本文介绍了一种利用遮挡区域外的像素所包含的全部信息的方法。使用迭代中值滤波法向内推断这些边缘像素。这使得填充区域内的空间分辨率变化平滑，并确保屏蔽像素和良好像素之间的无缝过渡。连续、狭窄特征中的间隙即使很大，也能高保真地重建。该方法在 MIT 授权的开源 Python 软件包 maskfill 中实现 (https://github.com/dokkum/maskfill)。我们用几个例子说明了该方法的性能，并将其与其他几种插值方案进行了比较。
{"title":"A Robust and Simple Method for Filling in Masked Data in Astronomical Images","authors":"Pieter van Dokkum, Imad Pasha","doi":"10.1088/1538-3873/ad2866","DOIUrl":"https://doi.org/10.1088/1538-3873/ad2866","url":null,"abstract":"Astronomical images often have regions with missing or unwanted information, such as bad pixels, bad columns, cosmic rays, masked objects, or residuals from imperfect model subtractions. In certain situations it can be essential, or preferable, to fill in these regions. Most existing methods use low order interpolations for this task. In this paper a method is described that uses the full information that is contained in the pixels just outside masked regions. These edge pixels are extrapolated inwards, using iterative median filtering. This leads to a smoothly varying spatial resolution within the filled-in regions, and ensures seamless transitions between masked pixels and good pixels. Gaps in continuous, narrow features can be reconstructed with high fidelity, even if they are large. The method is implemented in <monospace>maskfill</monospace>, an open-source MIT licensed Python package (<ext-link ext-link-type=\"uri\" xlink:href=\"https://github.com/dokkum/maskfill\" xlink:type=\"simple\">https://github.com/dokkum/maskfill</ext-link>). Its performance is illustrated with several examples, and compared to several alternative interpolation schemes.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314969","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}
Pub Date : 2024-03-07DOI: 10.1088/1538-3873/ad1ed4
Alan W. McConnachie, Christian R. Hayes, J. Gordon Robertson, John Pazder, Michael Ireland, Greg Burley, Vladimir Churilov, Jordan Lothrop, Ross Zhelem, Venu Kalari, André Anthony, Gabriella Baker, Trystyn Berg, Edward L. Chapin, Timothy Chin, Adam Densmore, Ruben Diaz, Jennifer Dunn, Michael L. Edgar, Tony Farrell, Veronica Firpo, Javier Fuentes, Manuel Gomez-Jimenez, Tim Hardy, David Henderson, Alexis Hill, Kathleen Labrie, Jaclyn Jensen, Sam Lambert, Jon Lawrence, G. Scott Macdonald, Steven Margheim, Bryan Millar, Rolf Muller, Jon G. Nielsen, Gabriel Pérez, Carlos Quiroz, Roque Ruiz-Carmona, Kim M. Sebo, Federico Sestito, Kareleyne Silva, Chris Simpson, Greg Smith, Sudharshan Venkatesan, Fletcher Waller, Lewis Waller, Ivan Wevers, Kim A. Venn, Peter Young, Katherine Silversides
The Gemini High Resolution Optical Spectrograph (GHOST) is a fiber-fed spectrograph system on the Gemini South telescope that provides simultaneous wavelength coverage from 348 to 1061 nm, and is designed for optimal performance between 363 and 950 nm. It can observe up to two objects simultaneously in a 7.′5 diameter field of regard at R ≃ 56,000 or a single object at R ≃ 75,000. The spectral resolution modes are obtained by using integral field units to image slice a 1.″2 aperture by a factor of five in width using 19 fibers in the high resolution mode and by a factor of three in width using 7 fibers in the standard resolution mode. GHOST is equipped with hardware to allow for precision radial velocity measurements, expected to approach meters per second precision. Here, we describe the basic design and operational capabilities of GHOST, and proceed to derive and quantify the key aspects of its on-sky performance that are of most relevance to its science users.
{"title":"The Science Performance of the Gemini High Resolution Optical Spectrograph","authors":"Alan W. McConnachie, Christian R. Hayes, J. Gordon Robertson, John Pazder, Michael Ireland, Greg Burley, Vladimir Churilov, Jordan Lothrop, Ross Zhelem, Venu Kalari, André Anthony, Gabriella Baker, Trystyn Berg, Edward L. Chapin, Timothy Chin, Adam Densmore, Ruben Diaz, Jennifer Dunn, Michael L. Edgar, Tony Farrell, Veronica Firpo, Javier Fuentes, Manuel Gomez-Jimenez, Tim Hardy, David Henderson, Alexis Hill, Kathleen Labrie, Jaclyn Jensen, Sam Lambert, Jon Lawrence, G. Scott Macdonald, Steven Margheim, Bryan Millar, Rolf Muller, Jon G. Nielsen, Gabriel Pérez, Carlos Quiroz, Roque Ruiz-Carmona, Kim M. Sebo, Federico Sestito, Kareleyne Silva, Chris Simpson, Greg Smith, Sudharshan Venkatesan, Fletcher Waller, Lewis Waller, Ivan Wevers, Kim A. Venn, Peter Young, Katherine Silversides","doi":"10.1088/1538-3873/ad1ed4","DOIUrl":"https://doi.org/10.1088/1538-3873/ad1ed4","url":null,"abstract":"The Gemini High Resolution Optical Spectrograph (GHOST) is a fiber-fed spectrograph system on the Gemini South telescope that provides simultaneous wavelength coverage from 348 to 1061 nm, and is designed for optimal performance between 363 and 950 nm. It can observe up to two objects simultaneously in a 7.′5 diameter field of regard at <italic toggle=\"yes\">R</italic> ≃ 56,000 or a single object at <italic toggle=\"yes\">R</italic> ≃ 75,000. The spectral resolution modes are obtained by using integral field units to image slice a 1.″2 aperture by a factor of five in width using 19 fibers in the high resolution mode and by a factor of three in width using 7 fibers in the standard resolution mode. GHOST is equipped with hardware to allow for precision radial velocity measurements, expected to approach meters per second precision. Here, we describe the basic design and operational capabilities of GHOST, and proceed to derive and quantify the key aspects of its on-sky performance that are of most relevance to its science users.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140314515","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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