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On the Potential of Spectroastrometry with Photonic Lanterns 利用光子灯进行光谱测量的潜力
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-13 DOI: arxiv-2409.09120
Yoo Jung Kim, Michael P. Fitzgerald, Jonathan Lin, Yinzi Xin, Daniel Levinstein, Steph Sallum, Nemanja Jovanovic, Sergio Leon-Saval
{"title":"On the Potential of Spectroastrometry with Photonic Lanterns","authors":"Yoo Jung Kim, Michael P. Fitzgerald, Jonathan Lin, Yinzi Xin, Daniel Levinstein, Steph Sallum, Nemanja Jovanovic, Sergio Leon-Saval","doi":"arxiv-2409.09120","DOIUrl":"https://doi.org/arxiv-2409.09120","url":null,"abstract":"We investigate the potential of photonic lantern (PL) fiber fed spectrometers\u0000for two-dimensional spectroastrometry. Spectroastrometry, a technique for\u0000studying small angular scales by measuring centroid shifts as a function of\u0000wavelength, is typically conducted using long-slit spectrographs. However,\u0000slit-based spectroastrometry requires observations with multiple position\u0000angles to measure two-dimensional spectroastrometric signals. In a typical\u0000configuration of PL-fed spectrometers, light from the focal plane is coupled\u0000into the few-moded PL, which is then split into several single-mode outputs,\u0000with the relative intensities containing astrometric information. The\u0000single-moded beams can be fed into a high-resolution spectrometer to measure\u0000wavelength-dependent centroid shifts. We perform numerical simulations of a\u0000standard 6-port PL and demonstrate its capability of measuring\u0000spectroastrometric signals. The effects of photon noise, wavefront errors, and\u0000chromaticity are investigated. When the PL is designed to have large linear\u0000responses to tip-tilts at the wavelengths of interest, the centroid shifts can\u0000be efficiently measured. Furthermore, we provide mock observations of detecting\u0000accreting protoplanets. PL spectroastrometry is potentially a simple and\u0000efficient technique for detecting spectroastrometric signals.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Predicting High Magnification Events in Microlensed Quasars in the Era of LSST using Recurrent Neural Networks 利用递归神经网络预测 LSST 时代微凝聚类星体中的高放大事件
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-13 DOI: arxiv-2409.08999
Joshua Fagin, Eric Paic, Favio Neira, Henry Best, Timo Anguita, Martin Millon, Matthew O'Dowd, Dominique Sluse, Georgios Vernardos
{"title":"Predicting High Magnification Events in Microlensed Quasars in the Era of LSST using Recurrent Neural Networks","authors":"Joshua Fagin, Eric Paic, Favio Neira, Henry Best, Timo Anguita, Martin Millon, Matthew O'Dowd, Dominique Sluse, Georgios Vernardos","doi":"arxiv-2409.08999","DOIUrl":"https://doi.org/arxiv-2409.08999","url":null,"abstract":"Upcoming wide field surveys such as the Rubin Observatory's Legacy Survey of\u0000Space and Time (LSST) will monitor thousands of strongly lensed quasars over a\u000010-year period. Many of these monitored quasars will undergo high magnification\u0000events (HMEs) through microlensing as the accretion disk crosses a caustic,\u0000places of infinite magnification. Microlensing allows us to map the inner\u0000regions of the accretion disk as it crosses a caustic, even at large\u0000cosmological distances. The observational cadences of LSST are not ideal for\u0000probing the inner regions of the accretion disk, so there is a need to predict\u0000HMEs as early as possible to trigger high-cadence multi-band or spectroscopic\u0000follow-up observations. Here we simulate a diverse and realistic sample of\u000010-year quasar microlensing light curves to train a recurrent neural network\u0000(RNN) to predict HMEs before they occur by classifying the location of the\u0000peaks at each time step. This is the first deep learning approach to predict\u0000HMEs. We give estimates at how well we expect to predict HME peaks during LSST\u0000and benchmark how our metrics change with different cadence strategies. With\u0000LSST-like observations, we can predict approximately 55% of HME peaks\u0000corresponding to tens to hundreds per year and a false positive rate of around\u000020% compared to the number of HMEs. Our network can be continuously applied\u0000throughout the LSST survey, providing crucial alerts to optimize follow-up\u0000resources.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Development of a Compton Imager Setup 开发康普顿成像仪装置
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-13 DOI: arxiv-2409.08822
Anuraag Arya, Harmanjeet Singh Bilkhu, Sandeep Vishwakarma, Hrishikesh Belatikar, Varun Bhalerao, Abhijeet Ghodgaonkar, Jayprakash G. Koyande, Aditi Marathe, N. P. S. Mithun, Sanjoli Narang, Sudhanshu Nimbalkar, Pranav Page, Sourav Palit, Arpit Patel, Amit Shetye, Siddharth Tallur, Shriharsh Tendulkar, Santosh Vadawale, Gaurav Waratkar
{"title":"Development of a Compton Imager Setup","authors":"Anuraag Arya, Harmanjeet Singh Bilkhu, Sandeep Vishwakarma, Hrishikesh Belatikar, Varun Bhalerao, Abhijeet Ghodgaonkar, Jayprakash G. Koyande, Aditi Marathe, N. P. S. Mithun, Sanjoli Narang, Sudhanshu Nimbalkar, Pranav Page, Sourav Palit, Arpit Patel, Amit Shetye, Siddharth Tallur, Shriharsh Tendulkar, Santosh Vadawale, Gaurav Waratkar","doi":"arxiv-2409.08822","DOIUrl":"https://doi.org/arxiv-2409.08822","url":null,"abstract":"Hard X-ray photons with energies in the range of hundreds of keV typically\u0000undergo Compton scattering when they are incident on a detector. In this\u0000process, an incident photon deposits a fraction of its energy at the point of\u0000incidence and continues onward with a change in direction that depends on the\u0000amount of energy deposited. By using a pair of detectors to detect the point of\u0000incidence and the direction of the scattered photon, we can calculate the\u0000scattering direction and angle. The position of a source in the sky can be\u0000reconstructed using many Compton photon pairs from a source. We demonstrate\u0000this principle in the laboratory by using a pair of Cadmium Zinc Telluride\u0000detectors sensitive in the energy range of 20-200 keV. The laboratory setup\u0000consists of the two detectors placed perpendicular to each other in a\u0000lead-lined box. The detectors are read out by a custom-programmed Xilinx PYNQ\u0000FPGA board, and data is then transferred to a PC. The detectors are first\u0000calibrated using lines from $^{241}mathrm{Am}$, $^{155}mathrm{Eu}$ and\u0000$^{133}mathrm{Ba}$ sources. We irradiated the detectors with a collimated\u0000$^{133}mathrm{Ba}$ source and identified Compton scattering events for the 356\u0000keV line. We run a Compton reconstruction algorithm and correctly infer the\u0000location of the source in the detector frame. This comprises a successful\u0000technology demonstration for a Compton imaging camera in the Hard X-ray regime.\u0000We present the details of our setup, the data acquisition process, and software\u0000algorithms, and showcase our results.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Radio Technosignature Search of TRAPPIST-1 with the Allen Telescope Array 利用艾伦望远镜阵列对 TRAPPIST-1 进行无线电技术特征搜索
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08313
Nick TusayDepartment of Astronomy & Astrophysics, The Pennsylvania State UniversityCenter for Exoplanets and Habitable WorldsPenn State Extraterrestrial Intelligence Center, Sofia Z. SheikhPenn State Extraterrestrial Intelligence CenterBreakthrough Listen, University of California, BerkeleySETI Institute, Evan L. SneedDepartment of Earth & Planetary Sciences, University of California, RiversideBreakthrough Listen, University of California, BerkeleyPenn State Extraterrestrial Intelligence Center, Wael FarahBreakthrough Listen, University of California, BerkeleySETI Institute, Alexander W. PollakSETI Institute, Luigi F. CruzSETI Institute, Andrew SiemionBreakthrough Listen, University of California, BerkeleySETI InstituteDepartment of Astronomy, University of California, Berkeley, David R. DeBoerDepartment of Astronomy, University of California, Berkeley, Jason T. WrightDepartment of Astronomy & Astrophysics, The Pennsylvania State UniversityCenter for Exoplanets and Habitable WorldsPenn State Extraterrestrial Intelligence Center
{"title":"A Radio Technosignature Search of TRAPPIST-1 with the Allen Telescope Array","authors":"Nick TusayDepartment of Astronomy & Astrophysics, The Pennsylvania State UniversityCenter for Exoplanets and Habitable WorldsPenn State Extraterrestrial Intelligence Center, Sofia Z. SheikhPenn State Extraterrestrial Intelligence CenterBreakthrough Listen, University of California, BerkeleySETI Institute, Evan L. SneedDepartment of Earth & Planetary Sciences, University of California, RiversideBreakthrough Listen, University of California, BerkeleyPenn State Extraterrestrial Intelligence Center, Wael FarahBreakthrough Listen, University of California, BerkeleySETI Institute, Alexander W. PollakSETI Institute, Luigi F. CruzSETI Institute, Andrew SiemionBreakthrough Listen, University of California, BerkeleySETI InstituteDepartment of Astronomy, University of California, Berkeley, David R. DeBoerDepartment of Astronomy, University of California, Berkeley, Jason T. WrightDepartment of Astronomy & Astrophysics, The Pennsylvania State UniversityCenter for Exoplanets and Habitable WorldsPenn State Extraterrestrial Intelligence Center","doi":"arxiv-2409.08313","DOIUrl":"https://doi.org/arxiv-2409.08313","url":null,"abstract":"Planet-planet occultations (PPOs) occur when one exoplanet occults another\u0000exoplanet in the same system as seen from the Earth's vantage point. PPOs may\u0000provide a unique opportunity to observe radio \"spillover\" from extraterrestrial\u0000intelligences' (ETIs) radio transmissions or radar being transmitted from the\u0000further exoplanet towards the nearer one for the purposes of communication or\u0000scientific exploration. Planetary systems with many tightly packed,\u0000low-inclination planets, such as TRAPPIST-1, are predicted to have frequent\u0000PPOs. Here, the narrowband technosignature search code turboSETI was used in\u0000combination with the newly developed NbeamAnalysis filtering pipeline to\u0000analyze 28 hours of beamformed data taken with the Allen Telescope Array (ATA)\u0000during late October and early November 2022, from 0.9--9.3~GHz, targeting\u0000TRAPPIST-1. During this observing window, 7 possible PPO events were predicted\u0000using the NbodyGradient code. The filtering pipeline reduced the original list\u0000of 25 million candidate signals down to 6 million by rejecting signals that\u0000were not sky-localized and, from these, identified a final list of 11127\u0000candidate signals above a power law cutoff designed to segregate signals by\u0000their attenuation and morphological similarity between beams. All signals were\u0000plotted for visual inspection, 2264 of which were found to occur during PPO\u0000windows. We report no detection of signals of non-human origin, with upper\u0000limits calculated for each PPO event exceeding EIRPs of 2.17--13.3 TW for\u0000minimally drifting signals and 40.8--421 TW in the maximally drifting case.\u0000This work constitutes the longest single-target radio SETI search of TRAPPIST-1\u0000to date.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Evaluation of South African Candidate Sites for an Expanded Event Horizon Telescope 评估南非用于扩展事件视界望远镜的候选地点
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08003
Senkhosi Simelane, Roger Deane, Athol Kemball, Roelf Botha, Roufurd Julie, Keitumetse Molamu, Adrian Tiplady, Aletha de Witt
{"title":"Evaluation of South African Candidate Sites for an Expanded Event Horizon Telescope","authors":"Senkhosi Simelane, Roger Deane, Athol Kemball, Roelf Botha, Roufurd Julie, Keitumetse Molamu, Adrian Tiplady, Aletha de Witt","doi":"arxiv-2409.08003","DOIUrl":"https://doi.org/arxiv-2409.08003","url":null,"abstract":"Global expansion of the Event Horizon Telescope (EHT) will see the strategic\u0000addition of antennas at new geographical locations, transforming the\u0000sensitivity and imaging fidelity of the $lambda sim 1,$mm EHT array. A\u0000possible South African EHT station would leverage a strong geographical\u0000advantage, local infrastructure, and radio astronomy expertise, and have strong\u0000synergies with the Africa Millimetre Telescope in Namibia. We assessed three\u0000South African candidate millimetre sites using climatological simulations and\u0000found at least two promising sites. These sites are comparable to some existing\u0000EHT stations during the typical April EHT observing window and outperform them\u0000during most of the year, especially the southern hemisphere winter.\u0000Interferometric simulations of Africa-enhanced EHT arrays under the simulated\u0000atmospheric conditions demonstrate the improved array performance. In typical\u0000weather, the number of reliable visibility detections increased considerably,\u0000especially at $(u, v)$-distances corresponding to the angular sizes of the\u0000Sagittarius A$^*$ and Messier 87$^*$ black hole shadow diameters\u0000($sim40,mathrm{mu}$as to $50,mathrm{mu}$as). The simulation results\u0000underscore the sizable, positive impact of a strategically placed South African\u0000EHT station on ngEHT objectives and the resulting black hole science.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
RISTRETTO: a VLT XAO design to reach Proxima Cen b in the visible RISTRETTO:VLT XAO 设计,用于在可见光下观测比邻仙后座 b
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08052
N. Blind, M. Shinde, I. Dinis, N. Restori, B. Chazelas, T. Fusco, O. Guyon, J. Kuehn, C. Lovis, P. Martinez, M. Motte, J. -F. Sauvage, A. Spang
{"title":"RISTRETTO: a VLT XAO design to reach Proxima Cen b in the visible","authors":"N. Blind, M. Shinde, I. Dinis, N. Restori, B. Chazelas, T. Fusco, O. Guyon, J. Kuehn, C. Lovis, P. Martinez, M. Motte, J. -F. Sauvage, A. Spang","doi":"arxiv-2409.08052","DOIUrl":"https://doi.org/arxiv-2409.08052","url":null,"abstract":"RISTRETTO is the evolution of the original idea of coupling the VLT\u0000instruments SPHERE and ESPRESSO cite{lovis_2016a}, aiming at High Dispersion\u0000Coronagraphy. RISTRETTO is a visitor instrument that should enable the\u0000characterization of the atmospheres of nearby exoplanets in reflected light, by\u0000using the technique of high-contrast, high-resolution spectroscopy. Its goal is\u0000to observe Prox Cen b and other planets placed at about 35mas from their star,\u0000i.e. $2lambda/D$ at $lambda$=750nm. The instrument is composed of an extreme\u0000adaptive optics, a coronagraphic Integral Field Unit, and a diffraction-limited\u0000spectrograph (R=140.000, $lambda =$620-840 nm). We present the RISTRETTO XAO architecture that reach the specification,\u0000providing contrasts down to $5times10^{-5}$ at 2$lambda/D$ from the star in\u0000the visible, in the presence of atmosphere and low wind effect. This\u0000performance is allowed by a new two-sensors-one-dm architecture, some\u0000variations to the already known concepts of unmodulated pyWFS and zWFS, and\u0000exploiting to the maximum of their capabilities the state-of-the-art high\u0000speed, low noise cameras & fast DM. We present the result of end-to-end\u0000simulations, that demonstrate stable closed loop operation of an unmodulated\u0000pyramid and a zernike WFS (together), and in presence of low wind effect.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Minimum Safe Distances for DE-STAR Space Lasers DE-STAR 空间激光器的最小安全距离
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08873
Adam Hibberd
{"title":"Minimum Safe Distances for DE-STAR Space Lasers","authors":"Adam Hibberd","doi":"arxiv-2409.08873","DOIUrl":"https://doi.org/arxiv-2409.08873","url":null,"abstract":"The prospect of phased laser arrays in space has received considerable\u0000attention in recent years, with applications to both planetary defence and\u0000space exploration. The most detailed investigation conducted into such a design\u0000is that of the DE-STAR phased array, standing for $textbf{D}$irected\u0000$textbf{E}$nergy $textbf{S}$ystems for $textbf{T}$argeting of\u0000$textbf{A}$steroids and explo$textbf{R}$ation. DE-STAR is a square modular\u0000design which exploits the energy created by banks of solar cells in space to\u0000generate and amplify the power of a laser beam. A specific DE-STAR design is\u0000expressed as DE-STAR n, where 'n' (typically in the range 0 - 4) equates to the\u0000log to base 10 of the side, in metres, of a square bank of lasers. With a\u0000DE-STAR 4 structure (10 km $times$ 10 km square) capable of generating a laser\u0000beam on the order of tens of gigawatts, clearly there is the potential for such\u0000an asset to be deployed as a weapon by targeting locations on Earth. This\u0000naturally leads to the question of what effective ways can this possible misuse\u0000be removed or at least mitigated, to ensure these powerful space lasers can\u0000only be used for their intended purpose, and never malevolent reasons. One\u0000solution would be to locate the DE-STAR far enough away so that the laser flux\u0000at Earth would be too low. Results indicate that given they should lie 1 au\u0000from the Sun, there are feasible locations for DE-STAR 0-2 arrays where there\u0000is no danger to Earth. For DE-STAR 4-5, such is their power, safety measures\u0000other than those considered here would have to be adopted. Positions in the\u0000Solar System where the DE-STAR lasers have no direct line-of-sight with Earth\u0000tend to be unstable, and would require regular corrections using an on-board\u0000propulsion system, or preferably using push-back from the laser itself.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Selective Dynamical Imaging of Interferometric Data 干涉测量数据的选择性动态成像
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08321
Joseph Farah, Peter Galison, Kazunori Akiyama, Katherine L. Bouman, Geoffrey C. Bower, Andrew Chael, Antonio Fuentes, José L. Gómez, Mareki Honma, Michael D. Johnson, Yutaro Kofuji, Daniel P. Marrone, Kotaro Moriyama, Ramesh Narayan, Dominic W. Pesce, Paul Tiede, Maciek Wielgus, Guang-Yao Zhao, The Event Horizon Telescope Collaboration
{"title":"Selective Dynamical Imaging of Interferometric Data","authors":"Joseph Farah, Peter Galison, Kazunori Akiyama, Katherine L. Bouman, Geoffrey C. Bower, Andrew Chael, Antonio Fuentes, José L. Gómez, Mareki Honma, Michael D. Johnson, Yutaro Kofuji, Daniel P. Marrone, Kotaro Moriyama, Ramesh Narayan, Dominic W. Pesce, Paul Tiede, Maciek Wielgus, Guang-Yao Zhao, The Event Horizon Telescope Collaboration","doi":"arxiv-2409.08321","DOIUrl":"https://doi.org/arxiv-2409.08321","url":null,"abstract":"Recent developments in very long baseline interferometry (VLBI) have made it\u0000possible for the Event Horizon Telescope (EHT) to resolve the innermost\u0000accretion flows of the largest supermassive black holes on the sky. The sparse\u0000nature of the EHT's $(u, v)$-coverage presents a challenge when attempting to\u0000resolve highly time-variable sources. We demonstrate that the changing (u,\u0000v)-coverage of the EHT can contain regions of time over the course of a single\u0000observation that facilitate dynamical imaging. These optimal time regions\u0000typically have projected baseline distributions that are approximately\u0000angularly isotropic and radially homogeneous. We derive a metric of coverage\u0000quality based on baseline isotropy and density that is capable of ranking array\u0000configurations by their ability to produce accurate dynamical reconstructions.\u0000We compare this metric to existing metrics in the literature and investigate\u0000their utility by performing dynamical reconstructions on synthetic data from\u0000simulated EHT observations of sources with simple orbital variability. We then\u0000use these results to make recommendations for imaging the 2017 EHT Sgr A* data\u0000set.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
JWST ice band profiles reveal mixed ice compositions in the HH 48 NE disk JWST 冰带剖面显示 HH 48 NE 圆盘中的混合冰成分
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08117
Jennifer B. Bergner, J. A. Sturm, Elettra L. Piacentino, M. K. McClure, Karin I. Oberg, A. C. A. Boogert, E. Dartois, M. N. Drozdovskaya, H. J. Fraser, Daniel Harsono, Sergio Ioppolo, Charles J. Law, Dariusz C. Lis, Brett A. McGuire, Gary J. Melnick, Jennifer A. Noble, M. E. Palumbo, Yvonne J. Pendleton, Giulia Perotti, Danna Qasim, W. R. M. Rocha, E. F. van Dishoeck
{"title":"JWST ice band profiles reveal mixed ice compositions in the HH 48 NE disk","authors":"Jennifer B. Bergner, J. A. Sturm, Elettra L. Piacentino, M. K. McClure, Karin I. Oberg, A. C. A. Boogert, E. Dartois, M. N. Drozdovskaya, H. J. Fraser, Daniel Harsono, Sergio Ioppolo, Charles J. Law, Dariusz C. Lis, Brett A. McGuire, Gary J. Melnick, Jennifer A. Noble, M. E. Palumbo, Yvonne J. Pendleton, Giulia Perotti, Danna Qasim, W. R. M. Rocha, E. F. van Dishoeck","doi":"arxiv-2409.08117","DOIUrl":"https://doi.org/arxiv-2409.08117","url":null,"abstract":"Planet formation is strongly influenced by the composition and distribution\u0000of volatiles within protoplanetary disks. With JWST, it is now possible to\u0000obtain direct observational constraints on disk ices, as recently demonstrated\u0000by the detection of ice absorption features towards the edge-on HH 48 NE disk\u0000as part of the Ice Age Early Release Science program. Here, we introduce a new\u0000radiative transfer modeling framework designed to retrieve the composition and\u0000mixing status of disk ices using their band profiles, and apply it to interpret\u0000the H2O, CO2, and CO ice bands observed towards the HH 48 NE disk. We show that\u0000the ices are largely present as mixtures, with strong evidence for CO trapping\u0000in both H2O and CO2 ice. The HH 48 NE disk ice composition (pure vs. polar vs.\u0000apolar fractions) is markedly different from earlier protostellar stages,\u0000implying thermal and/or chemical reprocessing during the formation or evolution\u0000of the disk. We infer low ice-phase C/O ratios around 0.1 throughout the disk,\u0000and also demonstrate that the mixing and entrapment of disk ices can\u0000dramatically affect the radial dependence of the C/O ratio. It is therefore\u0000imperative that realistic disk ice compositions are considered when comparing\u0000planetary compositions with potential formation scenarios, which will\u0000fortunately be possible for an increasing number of disks with JWST.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
nifty-ls: Fast and Accurate Lomb-Scargle Periodograms Using a Non-Uniform FFT nifty-ls:使用非均匀 FFT 快速准确地绘制 Lomb-Scargle 周期图
arXiv - PHYS - Instrumentation and Methods for Astrophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08090
Lehman H. Garrison, Dan Foreman-Mackey, Yu-hsuan Shih, Alex Barnett
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