Experimental Astronomy最新文献

{"title":"On-ground calibration of low gain response for Gamma-Ray Detectors onboard the GECAM satellite","authors":"Chaoyang Li,&nbsp;Wenxi Peng,&nbsp;Yaqing Liu,&nbsp;Xingzhu Cui,&nbsp;Zhenghua An,&nbsp;Xinqiao Li,&nbsp;Shaolin Xiong,&nbsp;Dali Zhang,&nbsp;Ke Gong,&nbsp;Min Gao,&nbsp;Dongya Guo,&nbsp;Xiaohua Liang,&nbsp;Xiaojing Liu,&nbsp;Rui Qiao,&nbsp;Xilei Sun,&nbsp;Jinzhou Wang,&nbsp;Xiangyang Wen,&nbsp;Yanbing Xu,&nbsp;Sheng Yang,&nbsp;Fan Zhang,&nbsp;Xiaoyun Zhao,&nbsp;Juncheng Liang,&nbsp;Haoran Liu,&nbsp;Zhijie Yang,&nbsp;Xiaofei Lan","doi":"10.1007/s10686-023-09892-x","DOIUrl":"10.1007/s10686-023-09892-x","url":null,"abstract":"<div><p>The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) consists of two small satellites operating in the same Earth orbit with opposite phases. Its scientific goal is to monitor the electromagnetic counterparts associated with Gravitational Wave events (GWE) and other cosmic high energy transient sources. As the main detector, the Gamma-Ray Detector (GRD) adopts LaBr<span>(_{3})</span>:Ce scintillator coupled with SiPM array. Each GRD has two output channels, i.e. high gain channel (8 <span>(sim )</span> 250 keV) and low gain channel (50 <span>(sim )</span> 6000 keV). In this paper, we present the low gain calibration results of GRDs with radioactive sources on ground, including the E-C relation, energy resolution, absolute detection efficiency and spatial response. Meanwhile, the consistency between the measurements and Geant4 simulation demonstrates the accuracy of the simulation code.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 1","pages":"49 - 60"},"PeriodicalIF":3.0,"publicationDate":"2023-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4624609","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}

{"title":"The energy consumption and carbon footprint of the LOFAR telescope","authors":"Gert Kruithof,&nbsp;Cees Bassa,&nbsp;Irene Bonati,&nbsp;Wim van Cappellen,&nbsp;Anne Doek,&nbsp;Nico Ebbendorf,&nbsp;Marchel Gerbers,&nbsp;Michiel van Haarlem,&nbsp;Ronald Halfwerk,&nbsp;Hanno Holties,&nbsp;Simone Kajuiter,&nbsp;Vlad Kondratiev,&nbsp;Henri Meulman,&nbsp;Roberto Pizzo,&nbsp;Timothy Shimwell,&nbsp;John Swinbank","doi":"10.1007/s10686-023-09901-z","DOIUrl":"10.1007/s10686-023-09901-z","url":null,"abstract":"<div><p>The LOw Frequency ARray (LOFAR) is a European radio telescope operating since 2010 in the frequency bands 10 - 80 MHz and 110 - 250 MHz. This article provides an analysis of the energy consumption and the carbon footprint of LOFAR. The approach used is a Life Cycle Analysis (LCA). We find that one year of LOFAR operations requires 3,627 MWh of electricity, 48,714 m³ gas and 135,497 liters of fuel. The associated carbon emission is 1,867 tCO2e/year. Results include the footprint stemming from operations of all LOFAR stations and central processing, but exclude scientific post-processing and activities. The electrical energy required for scientific processing is assessed separately. It ranges from 1% (standard imaging and time-domain), to 40% (wide field long baseline imaging) of the energy consumption for the observation. The outcome provides a transparent baseline in making LOFAR more sustainable and can serve as a blueprint for the analysis of other research infrastructures.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 2-3","pages":"687 - 714"},"PeriodicalIF":3.0,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10686-023-09901-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91386365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring the cosmic X-ray background accurately","authors":"Hancheng Li,&nbsp;Roland Walter,&nbsp;Nicolas Produit,&nbsp;Fiona Hubert","doi":"10.1007/s10686-023-09896-7","DOIUrl":"10.1007/s10686-023-09896-7","url":null,"abstract":"<div><p>Synthesis models of the diffuse Cosmic X-ray Background (CXB) suggest that it can be resolved into discrete sources, primarily Active Galactic Nuclei (AGNs). Measuring the CXB accurately offers a unique probe to study the AGN population in the nearby Universe. Current hard X-ray instruments suffer from the time-dependent background and cross-calibration issues. As a result, their measurements of the CXB normalization have an uncertainty of the order of <span>(sim )</span>15%. In this paper, we present the concept and simulated performances of a CXB detector, which could be operated on different platforms. With a 16-Unit CubeSat mission running for more than two years in space, such a detector could measure the CXB normalization with <span>(sim )</span>1% uncertainty.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 1","pages":"141 - 170"},"PeriodicalIF":3.0,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10686-023-09896-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4254273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Building a large affordable optical-NIR telescope (I): an alternate way to handle segmented primary mirror","authors":"Radhika Dharmadhikari,&nbsp;Padmakar Parihar,&nbsp;Annu Jacob","doi":"10.1007/s10686-023-09900-0","DOIUrl":"10.1007/s10686-023-09900-0","url":null,"abstract":"<div><p>The use of innovative ideas and the latest technology have undoubtedly brought down telescope costs substantially. However, there are still ways to further reduce the cost of optical ground-based telescopes and make them affordable to much larger and wide spread astronomical communities. In this and subsequent papers we are presenting our studies carried out towards building affordable mid-size telescopes of 4.0-6.0m in size. In the present era, segmented mirror technology has become the first choice for building moderate to large-size telescopes. In any Segmented Mirror Telescope (SMT) the most important part is its primary mirror control system (M1CS). The conventional M1CS is based on edge sensors and actuators, but such a system introduces many design and implementation complexities. In this paper, we propose to make use of an Off-axis Alignment and Phasing System (OAPS), which is an active mirror kind of control system working in real time to maintain the figure of a segmented primary mirror without the use of edge-sensors. The alignment and phasing system which is an integral part of any segmented telescope can be used in the real time at the off-axis. Through extensive simulations we have explored the feasibility of using an OAPS for co-alignment, co-focusing as well as co-phasing of segmented mirror telescopes. From our simulations we find that the co-alignment and co-focusing of the segments can be achieved with a guide star as faint as 16-18<span>(^{th})</span> magnitude. This implies that seeing limited performance for any segmented telescope can be easily accomplished without use of a complex edge sensor based control system. Whereas, to attain diffraction limited performance, mirror segments need to be co-phased with an accuracy of few tens of nanometers. In our simulations we have used a dispersed fringe sensor based phasing scheme, which can effectively work up to guide stars of 14<span>(^{th})</span> magnitude.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 2-3","pages":"569 - 604"},"PeriodicalIF":3.0,"publicationDate":"2023-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79635641","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}

{"title":"CAGIRE: a wide-field NIR imager for the COLIBRI 1.3 meter robotic telescope","authors":"Alix Nouvel de la Flèche,&nbsp;Jean-Luc Atteia,&nbsp;Jérémie Boy,&nbsp;Alain Klotz,&nbsp;Arthur Langlois,&nbsp;Marie Larrieu,&nbsp;Romain Mathon,&nbsp;Hervé Valentin,&nbsp;Philippe Ambert,&nbsp;Jean-Claude Clemens,&nbsp;Damien Dornic,&nbsp;Eric Kajfasz,&nbsp;Jean Le Graët,&nbsp;Olivier Llido,&nbsp;Aurélia Secroun,&nbsp;Olivier Boulade,&nbsp;Ayoub Bounab,&nbsp;Giacomo Badano,&nbsp;Olivier Gravrand,&nbsp;Sébastien Aufranc,&nbsp;Adrien Lamoure,&nbsp;Lilian Martineau,&nbsp;Laurent Rubaldo,&nbsp;Hervé Geoffray,&nbsp;François Gonzalez,&nbsp;Stéphane Basa,&nbsp;François Dolon,&nbsp;Johan Floriot,&nbsp;Simona Lombardo,&nbsp;Salvador Cuevas,&nbsp;Alejandro Farah,&nbsp;Jorge Fuentes,&nbsp;Rosalía Langarica,&nbsp;Alan M. Watson,&nbsp;Nathaniel Butler","doi":"10.1007/s10686-023-09903-x","DOIUrl":"10.1007/s10686-023-09903-x","url":null,"abstract":"<div><p>The use of high energy transients such as Gamma Ray Bursts (GRBs) as probes of the distant universe relies on the close collaboration between space and ground facilities. In this context, the Sino-French mission <i>SVOM</i> has been designed to combine a space and a ground segment and to make the most of their synergy. On the ground, the 1.3 meter robotic telescope COLIBRI, jointly developed by France and Mexico, will quickly point the sources detected by the space hard X-ray imager ECLAIRs, in order to detect and localise their visible/NIR counterpart and alert large telescopes in minutes. COLIBRI is equipped with two visible cameras, called DDRAGO-blue and DDRAGO-red, and an infrared camera, called CAGIRE, designed for the study of high redshift GRBs candidates. Being a low-noise NIR camera mounted at the focus of an alt-azimutal robotic telescope imposes specific requirements on CAGIRE. We describe here the main characteristics of the camera: its optical, mechanical and electronics architecture, the ALFA detector, and the operation of the camera on the telescope. The instrument description is completed by three sections presenting the calibration strategy, an image simulator incorporating known detector effects, and the automatic reduction software for the ramps acquired by the detector. This paper aims at providing an overview of the instrument before its installation on the telescope.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 2-3","pages":"645 - 685"},"PeriodicalIF":3.0,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78600674","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}

{"title":"Snapshot averaged Matrix Pencil Method (SAM) for direction of arrival estimation","authors":"Harsha Avinash Tanti,&nbsp;Abhirup Datta,&nbsp;S. Ananthakrishnan","doi":"10.1007/s10686-023-09897-6","DOIUrl":"10.1007/s10686-023-09897-6","url":null,"abstract":"<div><p>The estimation of the direction of electromagnetic (EM) waves from a radio source using electrically short antennas is one of the challenging problems in the field of radio astronomy. In this paper we have developed an algorithm which performs better in direction and polarization estimations than the existing algorithms. Our proposed algorithm Snapshot Averaged Matrix Pencil Method (SAM) is a modification to the existing Matrix Pencil Method (MPM) based Direction of Arrival (DoA) algorithm. In general, MPM estimates DoA of the incoherent EM waves in the spectra using unitary transformations and least square method (LSM). Our proposed SAM modification is made in context to the proposed Space Electric and Magnetic Sensor (SEAMS) mission to study the radio universe below 16 MHz. SAM introduces a snapshot averaging method to improve the incoherent frequency estimation thereby improving the accuracy of DoA estimation. It can also detect polarization to differentiate between Right Hand Circular Polarlization (RHCP), Right Hand Elliptical Polarlization (RHEP), Left Hand Circular Polarlization (LHCP), Left Hand Elliptical Polarlization (LHEP) and Linear Polarlization (LP). This paper discusses the formalism of SAM and shows the initial results of a scaled version of a DoA experiment at a resonant frequency of <span>(sim )</span>72 MHz.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 1","pages":"267 - 292"},"PeriodicalIF":3.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10686-023-09897-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5084665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The IAU recommended photometric system for ultraviolet astronomy","authors":"Ana I. Gómez de Castro,&nbsp;Noah Brosch,&nbsp;Daniela Bettoni,&nbsp;Leire Beitia-Antero,&nbsp;Paul Scowen,&nbsp;David Valls-Gabaud,&nbsp;Mikhail Sachkov","doi":"10.1007/s10686-023-09894-9","DOIUrl":"10.1007/s10686-023-09894-9","url":null,"abstract":"<div><p>In the current era when access to space is becoming easier and at a lower cost thanks to the standardised cubesat technology, numerous missions are expected to be launched to observe, particularly, at ultraviolet wavelengths. Given the reduced dimensions of the telescope that a cubesat can carry, most of these missions will be focused on photometric surveys of a reduced sample of targets of interest, and therefore each mission will define their own photometric bands according to their scientific objectives and orbital constraints. However, in order to provide a coherent view of the ultraviolet sky, the data should be post-processed under a common framework. In 2017, the IAU working group on ultraviolet astronomy identified the need to define such a common framework for the upcoming ultraviolet missions, and coordinated the definition of a standard set of photometric bands that could serve for homogenizing the current and future data. This paper presents the procedure adopted by the working group for the definition of the standard photometric system, that was approved by the IAU during the General Assembly Business Sessions held in August, 2021. The photometric system consists of seven bands, denoted as UV1-UV7, all included in the range 115 - 400 nm. Some of these bands are based on existing filters, while others have been defined as theoretical bands with constant throughput. This system is to be regarded as a set of synthetic bands for post-processing the data of any mission, and an example of its application to the SPARCS cubesat is also included. The photometric bands are publicly available and can be downloaded from https://www.nuva.eu/uv-photometry/.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 1","pages":"171 - 195"},"PeriodicalIF":3.0,"publicationDate":"2023-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10686-023-09894-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4936407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calculation of Cosmic microwave background radiation parameters using COBE/FIRAS dataset","authors":"Somita Dhal,&nbsp;Sneha Singh,&nbsp;Koustav Konar,&nbsp;R. K. Paul","doi":"10.1007/s10686-023-09904-w","DOIUrl":"10.1007/s10686-023-09904-w","url":null,"abstract":"<div><p>In this paper, we estimate the Cosmic Microwave Background (CMB) temperature using the data of the monopole spectrum from the Cosmic Background Explorer/ Far-Infrared Absolute Spectrophotometer (COBE/FIRAS). Utilising the idea of straight-line fitting, we obtain the temperature and chemical potential. The temperature of the CMB is found to be (2.725007 ± 0.000024) K (only statistical error) by using the monopole spectrum. Handling the data of the monopole spectrum the chemical potential is obtained as (-1.1 ± 3.4) × 10^–5 with an upper bound |µ| &lt; 5.7 × 10^–5(95% confidence level). The amplitude of the CMB dipole is found to be, T_amp = (3.47 ± 0.11) mK. We estimate an upper limit for the rms value of the fluctuation in chemical potential as Δµ &lt; 1.2 × 10^–4 (95% confidence level). The upper limit of y- distortion is calculated as y &lt; 1.0 × 10^–4 (95% confidence level).</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 2-3","pages":"715 - 726"},"PeriodicalIF":3.0,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81402484","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}

{"title":"Application of Infrared Thermal Imager to measure the temperature of Back-Up Structure of the TianMa radio telescope","authors":"Li Fu,&nbsp;Jiansen Tang,&nbsp;Rongbing Zhao,&nbsp;Yongbin Jiang,&nbsp;Jinqing Wang,&nbsp;Qinghui Liu,&nbsp;Zhiqiang Shen,&nbsp;Xu Wang,&nbsp;Haiming Liu","doi":"10.1007/s10686-023-09895-8","DOIUrl":"10.1007/s10686-023-09895-8","url":null,"abstract":"<div><p>Two infrared thermal imagers have been installed on the TianMa radio telescope (TMRT) to continuously monitor the temperature distributions of the back-up structure (BUS). In order to compensate the measurement error of the infrared thermal imager (ITI) for a BUS, a correction formula, as a function of measuring distance and viewing angle, is proposed. According to the relationship between the locations of the measurement points in the thermographic image and those in the actual structure, the 3D coordinates of the measurement points are determined by a finite element model of the BUS. Then, the measuring distances and viewing angles are calculated using 3D coordinates of the measurement points. The measurement accuracy of the ITI improves from ±2<span>(^{circ })</span>C to ±0.5<span>(^{circ })</span>C with the proposed formula. Additionally, based on the information of rotation angle and rotation speed of the elevation, the problem of the ITI moving with the elevation of the telescope in real time is solved. The temperature data at each elevation are recorded in excel documents respectively which are integrated into a document in chronological order through compiling program. Finally, the temperature of the measurement points at different altazimuthal positions is displayed as curves or contours. The thermal states of about 40% measuring points of the BUS are simultaneously monitored by the ITI, which provides accurate temperature distribution for the prediction of thermal deformations of the BUS.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 1","pages":"223 - 238"},"PeriodicalIF":3.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4981005","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}

{"title":"Radio astronomical images object detection and segmentation: a benchmark on deep learning methods","authors":"Renato Sortino,&nbsp;Daniel Magro,&nbsp;Giuseppe Fiameni,&nbsp;Eva Sciacca,&nbsp;Simone Riggi,&nbsp;Andrea DeMarco,&nbsp;Concetto Spampinato,&nbsp;Andrew M. Hopkins,&nbsp;Filomena Bufano,&nbsp;Francesco Schillirò,&nbsp;Cristobal Bordiu,&nbsp;Carmelo Pino","doi":"10.1007/s10686-023-09893-w","DOIUrl":"10.1007/s10686-023-09893-w","url":null,"abstract":"<div><p>In recent years, deep learning has been successfully applied in various scientific domains. Following these promising results and performances, it has recently also started being evaluated in the domain of radio astronomy. In particular, since radio astronomy is entering the Big Data era, with the advent of the largest telescope in the world - the Square Kilometre Array (SKA), the task of automatic object detection and instance segmentation is crucial for source finding and analysis. In this work, we explore the performance of the most affirmed deep learning approaches, applied to astronomical images obtained by radio interferometric instrumentation, to solve the task of automatic source detection. This is carried out by applying models designed to accomplish two different kinds of tasks: object detection and semantic segmentation. The goal is to provide an overview of existing techniques, in terms of prediction performance and computational efficiency, to scientists in the astrophysics community who would like to employ machine learning in their research.</p></div>","PeriodicalId":551,"journal":{"name":"Experimental Astronomy","volume":"56 1","pages":"293 - 331"},"PeriodicalIF":3.0,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4221746","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}