Pub Date : 2023-10-01DOI: 10.1088/1538-3873/acf61c
Uriel Conod, Kate Jackson, Paolo Turri, Scott Chapman, Olivier Lardière, Masen Lamb, Carlos Correia, Gaetano Sivo, Suresh Sivanandam, Jean-Pierre Véran
Abstract The Gemini Infrared Multi-Object Spectrograph (GIRMOS) will be a near-infrared, multi-object, medium spectral resolution, integral field spectrograph (IFS) for Gemini North Telescope, designed to operate behind the future Gemini North Adaptive Optics system (GNAO). In addition to a first ground layer Adaptive Optics (AO) correction in closed loop carried out by GNAO, each of the four GIRMOS IFSs will independently perform additional multi-object AO correction in open loop, resulting in an improved image quality that is critical to achieve top level science requirements. We present the baseline parameters and simulated performance of GIRMOS obtained by modeling both the GNAO and GIRMOS AO systems. The image quality requirement for GIRMOS is that 57% of the energy of an unresolved point-spread function ensquared within a 0.1 × 0.1 arcsecond at 2.0 μ m. It was established that GIRMOS will be an order 16 × 16 adaptive optics (AO) system after examining the tradeoffs between performance, risks and costs. The ensquared energy requirement will be met in median atmospheric conditions at Maunakea at 30° from zenith.
{"title":"The Adaptive Optics System for the Gemini Infrared Multi-Object Spectrograph: Performance Modeling","authors":"Uriel Conod, Kate Jackson, Paolo Turri, Scott Chapman, Olivier Lardière, Masen Lamb, Carlos Correia, Gaetano Sivo, Suresh Sivanandam, Jean-Pierre Véran","doi":"10.1088/1538-3873/acf61c","DOIUrl":"https://doi.org/10.1088/1538-3873/acf61c","url":null,"abstract":"Abstract The Gemini Infrared Multi-Object Spectrograph (GIRMOS) will be a near-infrared, multi-object, medium spectral resolution, integral field spectrograph (IFS) for Gemini North Telescope, designed to operate behind the future Gemini North Adaptive Optics system (GNAO). In addition to a first ground layer Adaptive Optics (AO) correction in closed loop carried out by GNAO, each of the four GIRMOS IFSs will independently perform additional multi-object AO correction in open loop, resulting in an improved image quality that is critical to achieve top level science requirements. We present the baseline parameters and simulated performance of GIRMOS obtained by modeling both the GNAO and GIRMOS AO systems. The image quality requirement for GIRMOS is that 57% of the energy of an unresolved point-spread function ensquared within a 0.1 × 0.1 arcsecond at 2.0 μ m. It was established that GIRMOS will be an order 16 × 16 adaptive optics (AO) system after examining the tradeoffs between performance, risks and costs. The ensquared energy requirement will be met in median atmospheric conditions at Maunakea at 30° from zenith.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136054513","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 : 2023-10-01DOI: 10.1088/1538-3873/acf789
Feng-jie Lei, Hong Wu
Abstract We analyzed the star formation surface density (Σ SFR ) between the global and H ii regions in a sample of 69 low surface brightness galaxies (LSBGs) and 68 star-forming (SF) galaxies using data from the H α images. The conventional global Σ SFR , which is defined as the star formation rate (SFR) divided by the area of the global galaxy, may not accurately describe the star formation activity in LSBGs due to the lower number of H ii regions compared to SF galaxies. To address this, we divide the global galaxy into two regions, the H ii region and the diffuse region, and then study the Σ SFR in each region. Our results show that both the SFR and area of the H ii regions in LSBGs are lower than those in SF galaxies, resulting in the H ii region’s Σ SFR (SFR/area) being slightly lower in LSBGs than in SF galaxies by 0.28 dex, although the global Σ SFR is at least an order of magnitude lower in LSBGs than in SF galaxies. Furthermore, a significant difference exists between the global and H ii regions in Σ SFR . In LSBGs, Σ SFR increased by 0.80 dex from the global region to the H ii region, while SF galaxies demonstrate a 0.54 dex increase, highlighting the crucial aspect of carefully selecting an appropriate aperture for Σ SFR calculations.
{"title":"Examining the Influence of the Regions on Star Formation Surface Density","authors":"Feng-jie Lei, Hong Wu","doi":"10.1088/1538-3873/acf789","DOIUrl":"https://doi.org/10.1088/1538-3873/acf789","url":null,"abstract":"Abstract We analyzed the star formation surface density (Σ SFR ) between the global and H ii regions in a sample of 69 low surface brightness galaxies (LSBGs) and 68 star-forming (SF) galaxies using data from the H α images. The conventional global Σ SFR , which is defined as the star formation rate (SFR) divided by the area of the global galaxy, may not accurately describe the star formation activity in LSBGs due to the lower number of H ii regions compared to SF galaxies. To address this, we divide the global galaxy into two regions, the H ii region and the diffuse region, and then study the Σ SFR in each region. Our results show that both the SFR and area of the H ii regions in LSBGs are lower than those in SF galaxies, resulting in the H ii region’s Σ SFR (SFR/area) being slightly lower in LSBGs than in SF galaxies by 0.28 dex, although the global Σ SFR is at least an order of magnitude lower in LSBGs than in SF galaxies. Furthermore, a significant difference exists between the global and H ii regions in Σ SFR . In LSBGs, Σ SFR increased by 0.80 dex from the global region to the H ii region, while SF galaxies demonstrate a 0.54 dex increase, highlighting the crucial aspect of carefully selecting an appropriate aperture for Σ SFR calculations.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134935171","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 : 2023-10-01DOI: 10.1088/1538-3873/acf787
N. R. Colmenares, J. B. R. Battat, D. P. Gonzales, T. W. Murphy, S. Sabhlok
Abstract The Apache Point Lunar Laser-ranging Operation (APOLLO) has been collecting lunar range measurements for 15 yr at millimeter accuracy. The median nightly range uncertainty since 2006 is 1.7 mm. A recently added Absolute Calibration System (ACS), providing an independent assessment of APOLLO system accuracy and the capability to correct lunar range data, revealed a ∼0.4% (10 ps) systematic error in the calibration of one piece of hardware that has been present for the entire history of APOLLO. The application of ACS-based timing corrections suggests systematic errors are reduced to <1 mm, such that overall data accuracy and precision are both ∼1 mm. This paper describes the processing of APOLLO/ACS data that converts photon-by-photon range measurements into the aggregated normal points that are used for science analyses. Additionally, we present methodologies to estimate timing corrections for range data lacking contemporaneous ACS photons, including range data collected prior to installation of the ACS. We also provide access to the full 15 yr archive of APOLLO normal points (2006 April 6–2020 December 27).
{"title":"Fifteen Years of Millimeter Accuracy Lunar Laser Ranging with APOLLO: Data Reduction and Calibration","authors":"N. R. Colmenares, J. B. R. Battat, D. P. Gonzales, T. W. Murphy, S. Sabhlok","doi":"10.1088/1538-3873/acf787","DOIUrl":"https://doi.org/10.1088/1538-3873/acf787","url":null,"abstract":"Abstract The Apache Point Lunar Laser-ranging Operation (APOLLO) has been collecting lunar range measurements for 15 yr at millimeter accuracy. The median nightly range uncertainty since 2006 is 1.7 mm. A recently added Absolute Calibration System (ACS), providing an independent assessment of APOLLO system accuracy and the capability to correct lunar range data, revealed a ∼0.4% (10 ps) systematic error in the calibration of one piece of hardware that has been present for the entire history of APOLLO. The application of ACS-based timing corrections suggests systematic errors are reduced to <1 mm, such that overall data accuracy and precision are both ∼1 mm. This paper describes the processing of APOLLO/ACS data that converts photon-by-photon range measurements into the aggregated normal points that are used for science analyses. Additionally, we present methodologies to estimate timing corrections for range data lacking contemporaneous ACS photons, including range data collected prior to installation of the ACS. We also provide access to the full 15 yr archive of APOLLO normal points (2006 April 6–2020 December 27).","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136117675","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 : 2023-10-01DOI: 10.1088/1538-3873/acff87
Peter Vereš, Richard Cloete, Robert Weryk, Abraham Loeb, Matthew J. Payne
Abstract We describe enhancements to the digest 2 software, a short-arc orbit classifier for heliocentric orbits. Digest 2 is primarily used by the Near-Earth Object (NEO) community to flag newly discovered objects for a immediate follow-up and has been a part of NEO discovery process for more than 15 yr. We have updated the solar system population model used to weight the digest 2 score according to the 2023 catalog of known solar system orbits and extended the list of mean uncertainties for 140 observatory codes. Moreover, we have added Astrometry Data Exchange Standard (ADES) input format support to digest 2, which provides additional information for the astrometry, such as positional uncertainties for each detection. The digest 2 code was also extended to read the roving observer astrometric format as well as the ability to compute a new parameter from the provided astrometric uncertainties ( RMS′ ) that can serve as an indicator of in-tracklet curvature when compared with tracklet’s great-circle fit rms. Comparison with the previous version of digest 2 confirmed the improvement in accuracy of NEO identification and found that using ADES XML input significantly reduces the computation time of the digest 2.
{"title":"Improvement of Digest2 NEO Classification Code—utilizing the Astrometry Data Exchange Standard","authors":"Peter Vereš, Richard Cloete, Robert Weryk, Abraham Loeb, Matthew J. Payne","doi":"10.1088/1538-3873/acff87","DOIUrl":"https://doi.org/10.1088/1538-3873/acff87","url":null,"abstract":"Abstract We describe enhancements to the digest 2 software, a short-arc orbit classifier for heliocentric orbits. Digest 2 is primarily used by the Near-Earth Object (NEO) community to flag newly discovered objects for a immediate follow-up and has been a part of NEO discovery process for more than 15 yr. We have updated the solar system population model used to weight the digest 2 score according to the 2023 catalog of known solar system orbits and extended the list of mean uncertainties for 140 observatory codes. Moreover, we have added Astrometry Data Exchange Standard (ADES) input format support to digest 2, which provides additional information for the astrometry, such as positional uncertainties for each detection. The digest 2 code was also extended to read the roving observer astrometric format as well as the ability to compute a new parameter from the provided astrometric uncertainties ( <?CDATA ${RMS}^{prime} $?> <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <mml:mi mathvariant=\"italic\">RMS</mml:mi> <mml:mo accent=\"false\">′</mml:mo> </mml:math> ) that can serve as an indicator of in-tracklet curvature when compared with tracklet’s great-circle fit rms. Comparison with the previous version of digest 2 confirmed the improvement in accuracy of NEO identification and found that using ADES XML input significantly reduces the computation time of the digest 2.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136159924","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 : 2023-10-01DOI: 10.1088/1538-3873/acdb9a
Kelly M. Hambleton, Federica B. Bianco, Rachel Street, Keaton Bell, David Buckley, Melissa Graham, Nina Hernitschek, Michael B. Lund, Elena Mason, Joshua Pepper, Andrej Prša, Markus Rabus, Claudia M. Raiteri, Róbert Szabó, Paula Szkody, Igor Andreoni, Simone Antoniucci, Barbara Balmaverde, Eric Bellm, Rosaria Bonito, Giuseppe Bono, Maria Teresa Botticella, Enzo Brocato, Katja Bučar Bricman, Enrico Cappellaro, Maria Isabel Carnerero, Ryan Chornock, Riley Clarke, Phil Cowperthwaite, Antonino Cucchiara, Filippo D’Ammando, Kristen C. Dage, Massimo Dall’Ora, James R. A. Davenport, Domitilla de Martino, Giulia de Somma, Marcella Di Criscienzo, Rosanne Di Stefano, Maria Drout, Michele Fabrizio, Giuliana Fiorentino, Poshak Gandhi, Alessia Garofalo, Teresa Giannini, Andreja Gomboc, Laura Greggio, Patrick Hartigan, Markus Hundertmark, Elizabeth Johnson, Michael Johnson, Tomislav Jurkic, Somayeh Khakpash, Silvio Leccia, Xiaolong Li, Davide Magurno, Konstantin Malanchev, Marcella Marconi, Raffaella Margutti, Silvia Marinoni, Nicolas Mauron, Roberto Molinaro, Anais Möller, Marc Moniez, Tatiana Muraveva, Ilaria Musella, Chow-Choong Ngeow, Andrea Pastorello, Vincenzo Petrecca, Silvia Piranomonte, Fabio Ragosta, Andrea Reguitti, Chiara Righi, Vincenzo Ripepi, Liliana Rivera Sandoval, Keivan G. Stassun, Michael Stroh, Giacomo Terreran, Virginia Trimble, Yiannis Tsapras, Sjoert van Velzen, Laura Venuti, Jorick S. Vink
Abstract The Vera C. Rubin Legacy Survey of Space and Time (LSST) holds the potential to revolutionize time domain astrophysics, reaching completely unexplored areas of the Universe and mapping variability time scales from minutes to a decade. To prepare to maximize the potential of the Rubin LSST data for the exploration of the transient and variable Universe, one of the four pillars of Rubin LSST science, the Transient and Variable Stars Science Collaboration, one of the eight Rubin LSST Science Collaborations, has identified research areas of interest and requirements, and paths to enable them. While our roadmap is ever-evolving, this document represents a snapshot of our plans and preparatory work in the final years and months leading up to the survey’s first light.
Vera C. Rubin时空遗赠调查(LSST)有可能彻底改变时域天体物理学，到达宇宙中完全未被探索的领域，并绘制从几分钟到十年不等的时间尺度的变化图。作为鲁宾LSST科学的四大支柱之一，瞬态和变星科学合作组织(鲁宾LSST科学合作组织之一)已经确定了感兴趣的研究领域和需求，以及实现这些领域的途径，以准备最大限度地发挥鲁宾LSST数据在探索瞬态和可变宇宙方面的潜力。虽然我们的路线图在不断发展，但这份文件代表了我们在调查开始前的最后几年和几个月里的计划和准备工作的快照。
{"title":"Rubin Observatory LSST Transients and Variable Stars Roadmap","authors":"Kelly M. Hambleton, Federica B. Bianco, Rachel Street, Keaton Bell, David Buckley, Melissa Graham, Nina Hernitschek, Michael B. Lund, Elena Mason, Joshua Pepper, Andrej Prša, Markus Rabus, Claudia M. Raiteri, Róbert Szabó, Paula Szkody, Igor Andreoni, Simone Antoniucci, Barbara Balmaverde, Eric Bellm, Rosaria Bonito, Giuseppe Bono, Maria Teresa Botticella, Enzo Brocato, Katja Bučar Bricman, Enrico Cappellaro, Maria Isabel Carnerero, Ryan Chornock, Riley Clarke, Phil Cowperthwaite, Antonino Cucchiara, Filippo D’Ammando, Kristen C. Dage, Massimo Dall’Ora, James R. A. Davenport, Domitilla de Martino, Giulia de Somma, Marcella Di Criscienzo, Rosanne Di Stefano, Maria Drout, Michele Fabrizio, Giuliana Fiorentino, Poshak Gandhi, Alessia Garofalo, Teresa Giannini, Andreja Gomboc, Laura Greggio, Patrick Hartigan, Markus Hundertmark, Elizabeth Johnson, Michael Johnson, Tomislav Jurkic, Somayeh Khakpash, Silvio Leccia, Xiaolong Li, Davide Magurno, Konstantin Malanchev, Marcella Marconi, Raffaella Margutti, Silvia Marinoni, Nicolas Mauron, Roberto Molinaro, Anais Möller, Marc Moniez, Tatiana Muraveva, Ilaria Musella, Chow-Choong Ngeow, Andrea Pastorello, Vincenzo Petrecca, Silvia Piranomonte, Fabio Ragosta, Andrea Reguitti, Chiara Righi, Vincenzo Ripepi, Liliana Rivera Sandoval, Keivan G. Stassun, Michael Stroh, Giacomo Terreran, Virginia Trimble, Yiannis Tsapras, Sjoert van Velzen, Laura Venuti, Jorick S. Vink","doi":"10.1088/1538-3873/acdb9a","DOIUrl":"https://doi.org/10.1088/1538-3873/acdb9a","url":null,"abstract":"Abstract The Vera C. Rubin Legacy Survey of Space and Time (LSST) holds the potential to revolutionize time domain astrophysics, reaching completely unexplored areas of the Universe and mapping variability time scales from minutes to a decade. To prepare to maximize the potential of the Rubin LSST data for the exploration of the transient and variable Universe, one of the four pillars of Rubin LSST science, the Transient and Variable Stars Science Collaboration, one of the eight Rubin LSST Science Collaborations, has identified research areas of interest and requirements, and paths to enable them. While our roadmap is ever-evolving, this document represents a snapshot of our plans and preparatory work in the final years and months leading up to the survey’s first light.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136168882","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 : 2023-10-01DOI: 10.1088/1538-3873/aceb2f
J. B. R. Battat, E. Adelberger, N. R. Colmenares, M. Farrah, D. P. Gonzales, C. D. Hoyle, R. J. McMillan, T. W. Murphy, S. Sabhlok, C. W. Stubbs
Abstract We present data from the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) covering the 15 yr span from 2006 April through the end of 2020. APOLLO measures the Earth–Moon separation by recording the round-trip travel time of photons from the Apache Point Observatory to five retro-reflector arrays on the Moon. The APOLLO data set, combined with the 50 yr archive of measurements from other lunar laser ranging (LLR) stations, can be used to probe fundamental physics such as gravity and Lorentz symmetry, as well as properties of the Moon itself. We show that range measurements performed by APOLLO since 2006 have a median nightly accuracy of 1.7 mm, which is significantly better than other LLR stations.
{"title":"Fifteen Years of Millimeter Accuracy Lunar Laser Ranging with APOLLO: Data Set Characterization","authors":"J. B. R. Battat, E. Adelberger, N. R. Colmenares, M. Farrah, D. P. Gonzales, C. D. Hoyle, R. J. McMillan, T. W. Murphy, S. Sabhlok, C. W. Stubbs","doi":"10.1088/1538-3873/aceb2f","DOIUrl":"https://doi.org/10.1088/1538-3873/aceb2f","url":null,"abstract":"Abstract We present data from the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) covering the 15 yr span from 2006 April through the end of 2020. APOLLO measures the Earth–Moon separation by recording the round-trip travel time of photons from the Apache Point Observatory to five retro-reflector arrays on the Moon. The APOLLO data set, combined with the 50 yr archive of measurements from other lunar laser ranging (LLR) stations, can be used to probe fundamental physics such as gravity and Lorentz symmetry, as well as properties of the Moon itself. We show that range measurements performed by APOLLO since 2006 have a median nightly accuracy of 1.7 mm, which is significantly better than other LLR stations.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136117674","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 : 2023-10-01DOI: 10.1088/1538-3873/acf8f7
Guoqiang Shen, Zhiqiang Zou, A-Li Luo, Shuxin Hong, Xiao Kong
Abstract The taxonomy of galaxy morphology plays an important role in astrophysics and provides great help for the study of galaxy evolution. To integrate the advantages of unsupervised learning without labels and supervised learning with high classification accuracy, this paper proposes a galaxy morphology classification model based on a momentum contrastive learning algorithm named Momentum Contrastive Learning Galaxy (MCL-Galaxy), which mainly includes two parts (i) pre-training of the model, where the ResNet_50 backbone network acts as an encoder to learn the galaxy morphology image features, which are stored in the queue and their consistency is ensured by using the momentum contrastive learning algorithm; and (ii) transfer learning, where Mahalanobis distance can assist in improving classification accuracy in downstream tasks where both encoder and queue are transferred. To evaluate the performance of MCL-Galaxy, we use the data set of the Galaxy Zoo challenge project on Kaggle for comparative testing. The experimental results show that the classification accuracy of MCL-Galaxy can reach 90.12%, which is 8.12% higher than the unsupervised state-of-the-art results. Although it is 3.1% lower than the advanced supervised method, it has the advantage of no label and can achieve a higher accuracy rate at the first epoch of classification iteration. This suggests that the gap between unsupervised and supervised representation learning in the field of Galaxy Morphologies classification tasks is well bridged.
{"title":"A Galaxy Morphology Classification Model Based on Momentum Contrastive Learning","authors":"Guoqiang Shen, Zhiqiang Zou, A-Li Luo, Shuxin Hong, Xiao Kong","doi":"10.1088/1538-3873/acf8f7","DOIUrl":"https://doi.org/10.1088/1538-3873/acf8f7","url":null,"abstract":"Abstract The taxonomy of galaxy morphology plays an important role in astrophysics and provides great help for the study of galaxy evolution. To integrate the advantages of unsupervised learning without labels and supervised learning with high classification accuracy, this paper proposes a galaxy morphology classification model based on a momentum contrastive learning algorithm named Momentum Contrastive Learning Galaxy (MCL-Galaxy), which mainly includes two parts (i) pre-training of the model, where the ResNet_50 backbone network acts as an encoder to learn the galaxy morphology image features, which are stored in the queue and their consistency is ensured by using the momentum contrastive learning algorithm; and (ii) transfer learning, where Mahalanobis distance can assist in improving classification accuracy in downstream tasks where both encoder and queue are transferred. To evaluate the performance of MCL-Galaxy, we use the data set of the Galaxy Zoo challenge project on Kaggle for comparative testing. The experimental results show that the classification accuracy of MCL-Galaxy can reach 90.12%, which is 8.12% higher than the unsupervised state-of-the-art results. Although it is 3.1% lower than the advanced supervised method, it has the advantage of no label and can achieve a higher accuracy rate at the first epoch of classification iteration. This suggests that the gap between unsupervised and supervised representation learning in the field of Galaxy Morphologies classification tasks is well bridged.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136160997","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 : 2023-10-01DOI: 10.1088/1538-3873/acf8f8
Zsófia V. Kovács-Stermeczky, József Vinkó
Abstract A Tidal Disruption Event (TDE) occurs when a supermassive black hole tidally disrupts a nearby passing star. The fallback accretion rate of the disrupted star may exceed the Eddington limit, which induces a supersonic outflow and a burst of luminosity, similar to an explosive event. Thus, TDEs can be detected as very luminous transients, and the number of observations for such events is increasing rapidly. In this paper we fit 20 TDE light curves with TiDE , a new public, object-oriented code designed to model optical TDE light curves. We compare our results with those obtained by the popular MOSFiT and the recently developed TDEmass codes, and discuss the possible sources of differences.
{"title":"Fitting Optical Light Curves of Tidal Disruption Events with TiDE","authors":"Zsófia V. Kovács-Stermeczky, József Vinkó","doi":"10.1088/1538-3873/acf8f8","DOIUrl":"https://doi.org/10.1088/1538-3873/acf8f8","url":null,"abstract":"Abstract A Tidal Disruption Event (TDE) occurs when a supermassive black hole tidally disrupts a nearby passing star. The fallback accretion rate of the disrupted star may exceed the Eddington limit, which induces a supersonic outflow and a burst of luminosity, similar to an explosive event. Thus, TDEs can be detected as very luminous transients, and the number of observations for such events is increasing rapidly. In this paper we fit 20 TDE light curves with TiDE , a new public, object-oriented code designed to model optical TDE light curves. We compare our results with those obtained by the popular MOSFiT and the recently developed TDEmass codes, and discuss the possible sources of differences.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135654236","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 : 2023-09-01DOI: 10.1088/1538-3873/acf072
Ming-Tang Chen, Keiichi Asada, Satoki Matsushita, Philippe Raffin, Makoto Inoue, Paul T. P. Ho, Chih-Chiang Han, Derek Kubo, Timothy Norton, Nimesh A. Patel, George Nystrom, Chih-Wei L. Huang, Pierre Martin-Cocher, Jun Yi Koay, Cristina Romero-Cañizales, Ching-Tang Liu, Teddy Huang, Kuan-Yu Liu, Tashun Wei, Shu-Hao Chang, Ryan Chilson, Peter Oshiro, Homin Jiang, Chao-Te Li, Geoffrey Bower, Paul Shaw, Hiroaki Nishioka, Patrick M. Koch, Chung-Cheng Chen, Ranjani Srinivasan, Ramprasad Rao, William Snow, Hao Jinchi, Kuo-Chang Han, Song-Chu Chang, Li-Ming Lu, Hideo Ogawa, Kimihiro Kimura, Yutaka Hasegawa, Hung-Yi Pu, Shoko Koyama, Masanori Nakamura, Daniel Bintley, Craig Walther, Per Friberg, Jessica Dempsey, T. K. Sriharan, Sivasankaran Srikanth, Sheperd S. Doeleman, Roger Brissenden, Juan-Carlos Algaba Marcos, Britt Jeter, Cheng-Yu Kuo, Jongho Park
Abstract In 2018, the Greenland Telescope (GLT) started scientific observation in Greenland. Since then, we have completed several significant improvements and added new capabilities to the telescope system. This paper presents a full review of the GLT system, a summary of our observation activities since 2018, the lessons learned from the operations in the Arctic regions, and the prospect of the telescope.
{"title":"The Greenland Telescope—Construction, Commissioning, and Operations in Pituffik","authors":"Ming-Tang Chen, Keiichi Asada, Satoki Matsushita, Philippe Raffin, Makoto Inoue, Paul T. P. Ho, Chih-Chiang Han, Derek Kubo, Timothy Norton, Nimesh A. Patel, George Nystrom, Chih-Wei L. Huang, Pierre Martin-Cocher, Jun Yi Koay, Cristina Romero-Cañizales, Ching-Tang Liu, Teddy Huang, Kuan-Yu Liu, Tashun Wei, Shu-Hao Chang, Ryan Chilson, Peter Oshiro, Homin Jiang, Chao-Te Li, Geoffrey Bower, Paul Shaw, Hiroaki Nishioka, Patrick M. Koch, Chung-Cheng Chen, Ranjani Srinivasan, Ramprasad Rao, William Snow, Hao Jinchi, Kuo-Chang Han, Song-Chu Chang, Li-Ming Lu, Hideo Ogawa, Kimihiro Kimura, Yutaka Hasegawa, Hung-Yi Pu, Shoko Koyama, Masanori Nakamura, Daniel Bintley, Craig Walther, Per Friberg, Jessica Dempsey, T. K. Sriharan, Sivasankaran Srikanth, Sheperd S. Doeleman, Roger Brissenden, Juan-Carlos Algaba Marcos, Britt Jeter, Cheng-Yu Kuo, Jongho Park","doi":"10.1088/1538-3873/acf072","DOIUrl":"https://doi.org/10.1088/1538-3873/acf072","url":null,"abstract":"Abstract In 2018, the Greenland Telescope (GLT) started scientific observation in Greenland. Since then, we have completed several significant improvements and added new capabilities to the telescope system. This paper presents a full review of the GLT system, a summary of our observation activities since 2018, the lessons learned from the operations in the Arctic regions, and the prospect of the telescope.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"307 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135297854","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 : 2023-09-01DOI: 10.1088/1538-3873/acf6e0
Òscar Maireles-González, Joan Bartrina-Rapesta, Miguel Hernández-Cabronero, Joan Serra-Sagristà
Abstract Each new generation of telescope produces increasingly larger astronomical data volumes, which are expected to reach the order of exabytes in the next decade. Effective and fast data compression methods are paramount to help the scientific community contain storage costs and improve transmission times. Astronomical data differs significantly from natural and Earth-observation images, asking for specifically tailored compression approaches. This paper presents a novel lossless compression technique that employs the discrete Haar wavelet transform within the JPEG 2000 standard. Its performance is compared to that of a comprehensive selection of compressors, including fpack, the most common technique in astronomical observatories, as well as other algorithms highly competitive for other types of data. Experiments are performed on a large data set of 16 bit integer images, produced by telescopes around the world and representative of a wide variety of astronomical scenarios. The proposed technique has two modes. The first mode outperforms all the other tested techniques in terms of compression performance. It surpasses the most competitive configuration of fpack by, respectively, 5.3% (about 0.3 bits per sample), having also 4.5% lower compression and decompression times. The second mode is the fastest among all tested techniques. Its compression and decompression times are 2.5 and 3.5 times faster than the fastest configuration of fpack, while also yielding a 2.4% better compression performance (0.15 bits per sample).
{"title":"Efficient Lossless Compression of Integer Astronomical Data","authors":"Òscar Maireles-González, Joan Bartrina-Rapesta, Miguel Hernández-Cabronero, Joan Serra-Sagristà","doi":"10.1088/1538-3873/acf6e0","DOIUrl":"https://doi.org/10.1088/1538-3873/acf6e0","url":null,"abstract":"Abstract Each new generation of telescope produces increasingly larger astronomical data volumes, which are expected to reach the order of exabytes in the next decade. Effective and fast data compression methods are paramount to help the scientific community contain storage costs and improve transmission times. Astronomical data differs significantly from natural and Earth-observation images, asking for specifically tailored compression approaches. This paper presents a novel lossless compression technique that employs the discrete Haar wavelet transform within the JPEG 2000 standard. Its performance is compared to that of a comprehensive selection of compressors, including fpack, the most common technique in astronomical observatories, as well as other algorithms highly competitive for other types of data. Experiments are performed on a large data set of 16 bit integer images, produced by telescopes around the world and representative of a wide variety of astronomical scenarios. The proposed technique has two modes. The first mode outperforms all the other tested techniques in terms of compression performance. It surpasses the most competitive configuration of fpack by, respectively, 5.3% (about 0.3 bits per sample), having also 4.5% lower compression and decompression times. The second mode is the fastest among all tested techniques. Its compression and decompression times are 2.5 and 3.5 times faster than the fastest configuration of fpack, while also yielding a 2.4% better compression performance (0.15 bits per sample).","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135587870","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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