Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.035001
Yinzi Xin, Jerry W. Xuan, D. Mawet, Jason J. Wang, G. Ruane, D. Echeverri, N. Jovanovic, C. Do Ó, Michael P. Fitzgerald, Katelyn Horstman, C. Hsu, Joshua Liberman, Ronald A. López, Caprice L. Phillips, B. Ren, J. Ruffio, Ben Sappey
Abstract. The Keck Planet Imager and Characterizer (KPIC) is an instrument at the Keck II telescope that enables high-resolution spectroscopy of directly imaged exoplanets and substellar companions. KPIC uses single-mode fibers to couple the adaptive optics system to Keck’s near-infrared spectrometer (NIRSPEC). However, KPIC’s sensitivity at small separations is limited by the leakage of stellar light into the fiber. Speckle nulling uses a deformable mirror (DM) to destructively interfere starlight with itself, a technique typically used to reduce stellar signal on a focal-plane imaging detector. We present the first on-sky demonstration of speckle nulling through an optical fiber with KPIC, using NIRSPEC to collect exposures that measure speckle phase for quasi-real-time wavefront control while also serving as science data. We repeat iterations of measurement and correction, each using at least five exposures (four with DM probes to determine phase and one unprobed exposure to measure the intensity) and taking about 6 min when using 59.0 s exposures, including NIRSPEC overheads. We show a decrease in the on-sky leaked starlight by a factor of 2.6 to 2.8 in the targeted spectral order, at a spatial separation of 2.0 λ / D in K-band. This corresponds to an estimated factor of 2.6 to 2.8 decrease in the required exposure time to reach a given signal-to-noise ratio, relative to conventional KPIC observations. The performance of speckle nulling is limited by instability in the speckle phase: when the loop is opened, the null-depth degrades by a factor of 2 on the timescale of a single phase measurement, which would limit the suppression that can be achieved. Future work includes exploring gradient-descent methods, which may be faster and thereby able to achieve deeper nulls. In the meantime, the speckle nulling algorithm demonstrated in this work can be used to decrease stellar leakage and improve the signal-to-noise of science observations.
{"title":"On-sky speckle nulling through a single-mode fiber with the Keck Planet Imager and Characterizer","authors":"Yinzi Xin, Jerry W. Xuan, D. Mawet, Jason J. Wang, G. Ruane, D. Echeverri, N. Jovanovic, C. Do Ó, Michael P. Fitzgerald, Katelyn Horstman, C. Hsu, Joshua Liberman, Ronald A. López, Caprice L. Phillips, B. Ren, J. Ruffio, Ben Sappey","doi":"10.1117/1.JATIS.9.3.035001","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.035001","url":null,"abstract":"Abstract. The Keck Planet Imager and Characterizer (KPIC) is an instrument at the Keck II telescope that enables high-resolution spectroscopy of directly imaged exoplanets and substellar companions. KPIC uses single-mode fibers to couple the adaptive optics system to Keck’s near-infrared spectrometer (NIRSPEC). However, KPIC’s sensitivity at small separations is limited by the leakage of stellar light into the fiber. Speckle nulling uses a deformable mirror (DM) to destructively interfere starlight with itself, a technique typically used to reduce stellar signal on a focal-plane imaging detector. We present the first on-sky demonstration of speckle nulling through an optical fiber with KPIC, using NIRSPEC to collect exposures that measure speckle phase for quasi-real-time wavefront control while also serving as science data. We repeat iterations of measurement and correction, each using at least five exposures (four with DM probes to determine phase and one unprobed exposure to measure the intensity) and taking about 6 min when using 59.0 s exposures, including NIRSPEC overheads. We show a decrease in the on-sky leaked starlight by a factor of 2.6 to 2.8 in the targeted spectral order, at a spatial separation of 2.0 λ / D in K-band. This corresponds to an estimated factor of 2.6 to 2.8 decrease in the required exposure time to reach a given signal-to-noise ratio, relative to conventional KPIC observations. The performance of speckle nulling is limited by instability in the speckle phase: when the loop is opened, the null-depth degrades by a factor of 2 on the timescale of a single phase measurement, which would limit the suppression that can be achieved. Future work includes exploring gradient-descent methods, which may be faster and thereby able to achieve deeper nulls. In the meantime, the speckle nulling algorithm demonstrated in this work can be used to decrease stellar leakage and improve the signal-to-noise of science observations.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79142806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.034003
M. Kubo, Y. Katsukawa, D. Hernández Expósito, A. Sánchez Gómez, M. Balaguer Jimenéz, D. Orozco Suárez, José M. Morales Fernández, B. Aparicio del Moral, Antonio J. Moreno Mantas, Eduardo Bailón Martínez, J. C. del Toro Iniesta, Y. Kawabata, C. Quintero Noda, T. Oba, R. Ishikawa, T. Shimizu
Abstract. The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) has been developed for the third flight of the Sunrise balloon-borne stratospheric solar observatory. The aim of the SCIP is to reveal the evolution of three-dimensional magnetic fields in the solar photosphere and chromosphere using spectropolarimetric measurements with a polarimetric precision of 0.03% (1σ). Multiple lines in the 770 and 850 nm wavelength bands are simultaneously observed with two 2 k × 2 k CMOS cameras at a frame rate of 31.25 Hz. Stokes profiles are calculated onboard by accumulating the images modulated by a polarization modulation unit, and then compression processes are applied to the two-dimensional maps of the Stokes profiles. This onboard data processing effectively reduces the data rate. SCIP electronics can handle large data formats at high speed. Before the implementation into the flight SCIP electronics, a performance verification of the onboard data processing was performed with synthetic SCIP data that were produced with a numerical simulation modeling the solar atmospheres. Finally, we verified that the high-speed onboard data processing was realized on ground with the flight hardware using images illuminated by natural sunlight or an LED light.
{"title":"High-speed data processing onboard sunrise chromospheric infrared spectropolarimeter for the SUNRISE III balloon telescope","authors":"M. Kubo, Y. Katsukawa, D. Hernández Expósito, A. Sánchez Gómez, M. Balaguer Jimenéz, D. Orozco Suárez, José M. Morales Fernández, B. Aparicio del Moral, Antonio J. Moreno Mantas, Eduardo Bailón Martínez, J. C. del Toro Iniesta, Y. Kawabata, C. Quintero Noda, T. Oba, R. Ishikawa, T. Shimizu","doi":"10.1117/1.JATIS.9.3.034003","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.034003","url":null,"abstract":"Abstract. The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) has been developed for the third flight of the Sunrise balloon-borne stratospheric solar observatory. The aim of the SCIP is to reveal the evolution of three-dimensional magnetic fields in the solar photosphere and chromosphere using spectropolarimetric measurements with a polarimetric precision of 0.03% (1σ). Multiple lines in the 770 and 850 nm wavelength bands are simultaneously observed with two 2 k × 2 k CMOS cameras at a frame rate of 31.25 Hz. Stokes profiles are calculated onboard by accumulating the images modulated by a polarization modulation unit, and then compression processes are applied to the two-dimensional maps of the Stokes profiles. This onboard data processing effectively reduces the data rate. SCIP electronics can handle large data formats at high speed. Before the implementation into the flight SCIP electronics, a performance verification of the onboard data processing was performed with synthetic SCIP data that were produced with a numerical simulation modeling the solar atmospheres. Finally, we verified that the high-speed onboard data processing was realized on ground with the flight hardware using images illuminated by natural sunlight or an LED light.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78795426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.034002
Shikha Sharma, Mahendra P. Singh, P. Chakraborty, R. Jyoti
Abstract. We developed a wideband multi-channel merge-split fast Fourier transform spectrometer (FFTS) using analog-to-digital convertors (ADC) for signal sampling and field-programmable gate arrays (FPGA) for real-time spectrum generation. The FFTS constitutes the backend of the sub-mm wave heterodyne spectroscopy telescope to observe emitted radiations from rotational transitions of CO (J: 2 → 1 and J: 3 → 2) with 50 arc sec angular resolution, aiming to provide the first comprehensive survey of molecular clouds in the Milky Way and nearby galaxies from the northern hemisphere (Hanle, India) at these frequencies. The FFTS provides 8 GHz instantaneous bandwidth at 1.6 MHz spectral resolution (extendable to 0.8 or 0.4 MHz) comprising four channels (spanning 218.898 to 220.898 GHz, 229.038 to 231.038 GHz, 329.087 to 331.087 GHz, and 344.295 to 346.295 GHz frequency bands) belonging to two receiver chains at 230 and 345 GHz operating in a double side band configuration. The channel placement for these four channels is done to cover 13CO (J:2 → 1) transition at 220.398 GHz, 12CO (J:2 → 1) transition at 230.538 GHz, 13CO (J:3 → 2) transition at 330.588 GHz, and 12CO (J:3 → 2) transition at 345.796 GHz with 1.5 GHz margin for red-shifts. Spectrometer design is presented along with spectral line profile simulations, hardware configuration, proposed methodology, system specifications, and scalable field-programmable gate arrays (FPGA) implementation architecture. Elements in the instrument design leverage simultaneous multi-channel acquisition for optimized FPGA utilization by merging the channel pair from the sideband separating (2SB) second stage intermediate frequency (IF) mixer during Fourier transform and subsequently splitting the generated spectra. System characterization results are presented, confirming instruments capable of stable spectroscopy with a wide bandwidth (instantaneous 8 GHz with four 2 GHz channels) and high-spectral sampling (1 / 0.5 / 0.25 MHz corresponding to scalable fast Fourier transform length of 4k / 8k / 16k respectively) that provides adequate spectral resolution for the science case. Wide dynamic range (49.3 dB) and fine radiometric resolution required for relative spectroscopic measurements is realized by sampling IF signals with 12-bits ADCs. Variable spectral accumulation time facilitates improvements in the signal to noise ratio proportional to the square root of the number of coherent averaged cycles, covering various target dependent (longer dwell time for a single target) or scanning dependent (e.g., drift scanning mode matching earth’s rotation) dwell time requirements.
{"title":"Wideband digital multi-channel merge-split fast Fourier transform spectrometer: design and characterization","authors":"Shikha Sharma, Mahendra P. Singh, P. Chakraborty, R. Jyoti","doi":"10.1117/1.JATIS.9.3.034002","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.034002","url":null,"abstract":"Abstract. We developed a wideband multi-channel merge-split fast Fourier transform spectrometer (FFTS) using analog-to-digital convertors (ADC) for signal sampling and field-programmable gate arrays (FPGA) for real-time spectrum generation. The FFTS constitutes the backend of the sub-mm wave heterodyne spectroscopy telescope to observe emitted radiations from rotational transitions of CO (J: 2 → 1 and J: 3 → 2) with 50 arc sec angular resolution, aiming to provide the first comprehensive survey of molecular clouds in the Milky Way and nearby galaxies from the northern hemisphere (Hanle, India) at these frequencies. The FFTS provides 8 GHz instantaneous bandwidth at 1.6 MHz spectral resolution (extendable to 0.8 or 0.4 MHz) comprising four channels (spanning 218.898 to 220.898 GHz, 229.038 to 231.038 GHz, 329.087 to 331.087 GHz, and 344.295 to 346.295 GHz frequency bands) belonging to two receiver chains at 230 and 345 GHz operating in a double side band configuration. The channel placement for these four channels is done to cover 13CO (J:2 → 1) transition at 220.398 GHz, 12CO (J:2 → 1) transition at 230.538 GHz, 13CO (J:3 → 2) transition at 330.588 GHz, and 12CO (J:3 → 2) transition at 345.796 GHz with 1.5 GHz margin for red-shifts. Spectrometer design is presented along with spectral line profile simulations, hardware configuration, proposed methodology, system specifications, and scalable field-programmable gate arrays (FPGA) implementation architecture. Elements in the instrument design leverage simultaneous multi-channel acquisition for optimized FPGA utilization by merging the channel pair from the sideband separating (2SB) second stage intermediate frequency (IF) mixer during Fourier transform and subsequently splitting the generated spectra. System characterization results are presented, confirming instruments capable of stable spectroscopy with a wide bandwidth (instantaneous 8 GHz with four 2 GHz channels) and high-spectral sampling (1 / 0.5 / 0.25 MHz corresponding to scalable fast Fourier transform length of 4k / 8k / 16k respectively) that provides adequate spectral resolution for the science case. Wide dynamic range (49.3 dB) and fine radiometric resolution required for relative spectroscopic measurements is realized by sampling IF signals with 12-bits ADCs. Variable spectral accumulation time facilitates improvements in the signal to noise ratio proportional to the square root of the number of coherent averaged cycles, covering various target dependent (longer dwell time for a single target) or scanning dependent (e.g., drift scanning mode matching earth’s rotation) dwell time requirements.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72457029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.037002
Chang-Gone Kim, J. Sánchez-Gallego, P. Bilgi, Mingyeong Yang, F. Briegel, Tae-Geun Ji, N. Konidaris, Taeeun Kim, Hojae Ahn, Mingyu Jeon, Hyun Chul Park, Hye-In Lee, C. Froning, S. Ramírez, N. Drory, J. Kollmeier, S. Pak
Abstract. Local Volume Mapper Spectrograph Control Package (LVMSCP) is the software that controls three spectrographs to acquire science spectral data cubes automatically. The software architecture design based on Python 3.9 follows a hierarchical structure of Actors, the unit that controls each piece of hardware. We used the software framework Codified Likeness Utility to implement each Actor. The Actors communicate with each other through RabbitMQ, which implements the Advanced Message Queuing Protocol. The Actor applies asynchronous programming with non-blocking procedures as the three spectrographs should operate simultaneously. For the requirement of incremental code change and management in the collaboration of the developers, we adopted the SDSS Github Action, which supports continuous integration/continuous deployment. As a result, unit testing with Pytest tested the individual components of the software, respectively, and lab testing with LVMSCP provided the spectra data for the spectrograph calibration. The LVMSCP provides the application programming interface to the Robotic Observation Package to fulfill the required scientific survey execution for the spectrographs.
{"title":"Automatic spectrograph control software for SDSS-V Local Volume Mapper","authors":"Chang-Gone Kim, J. Sánchez-Gallego, P. Bilgi, Mingyeong Yang, F. Briegel, Tae-Geun Ji, N. Konidaris, Taeeun Kim, Hojae Ahn, Mingyu Jeon, Hyun Chul Park, Hye-In Lee, C. Froning, S. Ramírez, N. Drory, J. Kollmeier, S. Pak","doi":"10.1117/1.JATIS.9.3.037002","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.037002","url":null,"abstract":"Abstract. Local Volume Mapper Spectrograph Control Package (LVMSCP) is the software that controls three spectrographs to acquire science spectral data cubes automatically. The software architecture design based on Python 3.9 follows a hierarchical structure of Actors, the unit that controls each piece of hardware. We used the software framework Codified Likeness Utility to implement each Actor. The Actors communicate with each other through RabbitMQ, which implements the Advanced Message Queuing Protocol. The Actor applies asynchronous programming with non-blocking procedures as the three spectrographs should operate simultaneously. For the requirement of incremental code change and management in the collaboration of the developers, we adopted the SDSS Github Action, which supports continuous integration/continuous deployment. As a result, unit testing with Pytest tested the individual components of the software, respectively, and lab testing with LVMSCP provided the spectra data for the spectrograph calibration. The LVMSCP provides the application programming interface to the Robotic Observation Package to fulfill the required scientific survey execution for the spectrographs.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74584289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.037001
Rachel Dunwoody, M. Doyle, D. Murphy, Gabriel Finneran, D. O’Callaghan, Jack Reilly, Joseph W. Thompson, Sai Krishna Reddy Akarapu, Cuán de Barra, L. Cotter, Aaron Empey, Joseph Fisher, Joe Mangan, Caimin McKenna, Bas Stijnen, L. Hanlon, David J. McKeown, William J. O'Connor, Alexey Uliyanov, R. Wall, B. Shortt, S. McBreen
Abstract. CubeSats provide opportunities for science and technology demonstration missions with low-cost solutions and short project timescales, in particular, for studying gamma-ray bursts (GRBs) in the multi-messenger era. A robust operations strategy for scientific CubeSat projects is key to optimizing the results obtained from the experimental instruments. The Educational Irish Research Satellite-1 (EIRSAT-1) is a 2U CubeSat with three payloads, including a bespoke gamma-ray detector, gamma-ray module (GMOD), developed in-house for the detection of GRBs. The detection and reporting of GRB triggers to the scientific community complicates and drives the mission operational strategy. The operational procedures developed for commissioning and operating GMOD are detailed. The successful operation of EIRSAT-1 will facilitate the detection of ∼15 GRBs / year in low Earth orbit. To increase the likelihood of mission success, the project is following a prototype model philosophy, building, and testing, both an engineering qualification model (EQM) and flight model. The EIRSAT-1 operations manual is the document that will instruct operators in commanding the spacecraft correctly and efficiently throughout the mission lifetime. The operations manual must be refined in parallel to payload development. This two-model philosophy has provided time for the early development of the EIRSAT-1 operations manual with the EQM. The EIRSAT-1 operations manual has undergone incremental updates based on feedback from operational development tests (ODTs), and a version with 35 procedures was frozen prior to the month-long EQM mission test (MT). Specifically, the objective of our work is to validate and refine the operations manual using the EQM MT process. Although the ODTs were effective preparation, the MT process highlighted issues, such as procedures operators found convoluted, and scenarios not yet considered during the initial development stages. Two new procedures were identified, 8 procedures required major updates, 15 required minor updates, and the remaining 12 required no improvements after the MT. The validation process facilitated operator training in mission representative conditions, such as GRB triggering data downlink with GMOD, and the major lessons learned during the development and validation process are presented.
{"title":"Development, description, and validation of the operations manual for EIRSAT-1, a 2U CubeSat with a gamma-ray burst detector","authors":"Rachel Dunwoody, M. Doyle, D. Murphy, Gabriel Finneran, D. O’Callaghan, Jack Reilly, Joseph W. Thompson, Sai Krishna Reddy Akarapu, Cuán de Barra, L. Cotter, Aaron Empey, Joseph Fisher, Joe Mangan, Caimin McKenna, Bas Stijnen, L. Hanlon, David J. McKeown, William J. O'Connor, Alexey Uliyanov, R. Wall, B. Shortt, S. McBreen","doi":"10.1117/1.JATIS.9.3.037001","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.037001","url":null,"abstract":"Abstract. CubeSats provide opportunities for science and technology demonstration missions with low-cost solutions and short project timescales, in particular, for studying gamma-ray bursts (GRBs) in the multi-messenger era. A robust operations strategy for scientific CubeSat projects is key to optimizing the results obtained from the experimental instruments. The Educational Irish Research Satellite-1 (EIRSAT-1) is a 2U CubeSat with three payloads, including a bespoke gamma-ray detector, gamma-ray module (GMOD), developed in-house for the detection of GRBs. The detection and reporting of GRB triggers to the scientific community complicates and drives the mission operational strategy. The operational procedures developed for commissioning and operating GMOD are detailed. The successful operation of EIRSAT-1 will facilitate the detection of ∼15 GRBs / year in low Earth orbit. To increase the likelihood of mission success, the project is following a prototype model philosophy, building, and testing, both an engineering qualification model (EQM) and flight model. The EIRSAT-1 operations manual is the document that will instruct operators in commanding the spacecraft correctly and efficiently throughout the mission lifetime. The operations manual must be refined in parallel to payload development. This two-model philosophy has provided time for the early development of the EIRSAT-1 operations manual with the EQM. The EIRSAT-1 operations manual has undergone incremental updates based on feedback from operational development tests (ODTs), and a version with 35 procedures was frozen prior to the month-long EQM mission test (MT). Specifically, the objective of our work is to validate and refine the operations manual using the EQM MT process. Although the ODTs were effective preparation, the MT process highlighted issues, such as procedures operators found convoluted, and scenarios not yet considered during the initial development stages. Two new procedures were identified, 8 procedures required major updates, 15 required minor updates, and the remaining 12 required no improvements after the MT. The validation process facilitated operator training in mission representative conditions, such as GRB triggering data downlink with GMOD, and the major lessons learned during the development and validation process are presented.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89930407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.038005
Nichole Gray, Cameron T. Pratt, J. Bregman
Abstract. The absorption by gas toward background continuum sources informs us about the cosmic density of gas components as well as the hosts responsible for the absorption (galaxies, clusters, and cosmic filaments). Cosmic absorption line distributions are distorted near the detection threshold (S / N ≈ 3) due to true lines being scattered to a lower signal-to-noise (S/N) and false detections occurring at the same S/N. We simulate absorption line distributions in the presence of noise and consider two models for recovery: a parametric fitting of the noise plus a cut-off power law absorption line distribution and a non-parametric fit in which the negative absorption line distribution (emission lines) is subtracted from the positive S/N absorption line distribution (flip and subtract). We show that both approaches work equally well and can use data with S / N ≳ 3 to constrain the fit. For an input of about 100 absorption line systems, the number of systems is recovered to ≈14 % . This investigation examined the O VII X-ray absorption line distribution, but the approach should be broadly applicable for statistically well-behaved data.
摘要气体对背景连续源的吸收告诉我们气体成分的宇宙密度，以及负责吸收的宿主(星系、星系团和宇宙细丝)。在探测阈值(S/N≈3)附近，宇宙吸收线的分布被扭曲，这是由于真线被散射到较低的信噪比(S/N)，而在相同的信噪比下发生假检测。我们模拟了存在噪声的吸收线分布，并考虑了两种恢复模型:噪声的参数拟合加上截止功率律吸收线分布和非参数拟合，其中负吸收线分布(发射线)从正S/N吸收线分布中减去(翻转和减去)。我们证明这两种方法都同样有效，并且可以使用S / N > 3的数据来约束拟合。对于大约100个吸收线系统的输入，系统的数量恢复到≈14%。本研究考察了ovii x射线吸收线分布，但该方法应广泛适用于统计上表现良好的数据。
{"title":"Recovering the O VII absorption distributions from X-ray data","authors":"Nichole Gray, Cameron T. Pratt, J. Bregman","doi":"10.1117/1.JATIS.9.3.038005","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.038005","url":null,"abstract":"Abstract. The absorption by gas toward background continuum sources informs us about the cosmic density of gas components as well as the hosts responsible for the absorption (galaxies, clusters, and cosmic filaments). Cosmic absorption line distributions are distorted near the detection threshold (S / N ≈ 3) due to true lines being scattered to a lower signal-to-noise (S/N) and false detections occurring at the same S/N. We simulate absorption line distributions in the presence of noise and consider two models for recovery: a parametric fitting of the noise plus a cut-off power law absorption line distribution and a non-parametric fit in which the negative absorption line distribution (emission lines) is subtracted from the positive S/N absorption line distribution (flip and subtract). We show that both approaches work equally well and can use data with S / N ≳ 3 to constrain the fit. For an input of about 100 absorption line systems, the number of systems is recovered to ≈14 % . This investigation examined the O VII X-ray absorption line distribution, but the approach should be broadly applicable for statistically well-behaved data.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83013322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.034005
N. Montinaro, U. Lo Cicero, F. D'anca, E. Bozzo, S. Paltani, M. Barbera
Abstract. The x-ray detectors on board astrophysics space missions require optical blocking filters that are highly transparent to x-rays. The filter design typically consists of a polymeric film that is a few tens of nanometers thick coated with aluminium. Due to the large size of the filter membrane (from a few tens to a few hundred square centimeters) and the extreme aspect ratio, together with severe loading conditions during launch and different stoichiometries of the polymer that could change its mechanical properties, a characterization study of the employed material is needed. The plane strain bulge test is a well-accepted methodology for the mechanical testing of structures that are less than a micrometer thick, and especially for freestanding membranes. Unfortunately, testing such ultra-thin films is not a simple task due to residual stress and experimental uncertainty at very low pressure. In this work, the elastic properties of an extremely thin (between 45 and 415 nm) membrane made of bare polyimide and coated with aluminium were derived through adopting a combined experimental-numerical methodology based on the bulge test and numerical simulations.
{"title":"Elastic characterization of nanometer-thick polymeric film for astrophysics application with an experimental-numerical method","authors":"N. Montinaro, U. Lo Cicero, F. D'anca, E. Bozzo, S. Paltani, M. Barbera","doi":"10.1117/1.JATIS.9.3.034005","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.034005","url":null,"abstract":"Abstract. The x-ray detectors on board astrophysics space missions require optical blocking filters that are highly transparent to x-rays. The filter design typically consists of a polymeric film that is a few tens of nanometers thick coated with aluminium. Due to the large size of the filter membrane (from a few tens to a few hundred square centimeters) and the extreme aspect ratio, together with severe loading conditions during launch and different stoichiometries of the polymer that could change its mechanical properties, a characterization study of the employed material is needed. The plane strain bulge test is a well-accepted methodology for the mechanical testing of structures that are less than a micrometer thick, and especially for freestanding membranes. Unfortunately, testing such ultra-thin films is not a simple task due to residual stress and experimental uncertainty at very low pressure. In this work, the elastic properties of an extremely thin (between 45 and 415 nm) membrane made of bare polyimide and coated with aluminium were derived through adopting a combined experimental-numerical methodology based on the bulge test and numerical simulations.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88104681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.036001
M. Cisneros-González, D. Bolsée, N. Pereira, Lionel Van Laeken, L. Jacobs, A. Vandaele, Ö. Karatekin, C. Lauzin, S. Robert
Abstract. When developing new astronomical instruments, there is a need to perform the characterization of their individual components, especially the detectors, to ensure that their performances comply with the scientific objectives of the instrument. A visible-near infrared (VIS-NIR) facility was developed for the absolute and relative radiometric characterization of space-based detectors at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB). The facility operates from 0.4 to 2.65 μm in an ISO-5 environment. It offers a tunable monochromatic flux with a high level of straylight rejection (10 − 8) and 2% uniformity, over a four-decade range of intensity with adjustable bandwidth. Latency measurements are also possible. Thermalization is offered within a precision of 7 mK between 50 K and 382 K. The ultimate vacuum level of the detector chamber is below 10 − 6 mbar. A robust security system avoids both reaching temperatures outside the operational range of the detector and its electronics, and contamination due to vacuum loss. The facility was already used to characterize the VIS-NIR detectors of the Moons And Jupiter Imaging Spectrometer (MAJIS), one of the instruments on board the Jupiter ICy Moons Explorer (JUICE). The versatility provided by the VIS-NIR facility allows its use for the characterization of other astronomical detectors.
{"title":"Facility for the radiometric characterization of space-based visible-near infrared detectors","authors":"M. Cisneros-González, D. Bolsée, N. Pereira, Lionel Van Laeken, L. Jacobs, A. Vandaele, Ö. Karatekin, C. Lauzin, S. Robert","doi":"10.1117/1.JATIS.9.3.036001","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.036001","url":null,"abstract":"Abstract. When developing new astronomical instruments, there is a need to perform the characterization of their individual components, especially the detectors, to ensure that their performances comply with the scientific objectives of the instrument. A visible-near infrared (VIS-NIR) facility was developed for the absolute and relative radiometric characterization of space-based detectors at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB). The facility operates from 0.4 to 2.65 μm in an ISO-5 environment. It offers a tunable monochromatic flux with a high level of straylight rejection (10 − 8) and 2% uniformity, over a four-decade range of intensity with adjustable bandwidth. Latency measurements are also possible. Thermalization is offered within a precision of 7 mK between 50 K and 382 K. The ultimate vacuum level of the detector chamber is below 10 − 6 mbar. A robust security system avoids both reaching temperatures outside the operational range of the detector and its electronics, and contamination due to vacuum loss. The facility was already used to characterize the VIS-NIR detectors of the Moons And Jupiter Imaging Spectrometer (MAJIS), one of the instruments on board the Jupiter ICy Moons Explorer (JUICE). The versatility provided by the VIS-NIR facility allows its use for the characterization of other astronomical detectors.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77857493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.038004
Akira C. Naruse, T. Kamizuka, T. Miyata, S. Sako, R. Ohsawa, K. Asano, Atsushi Nishimura, I. Sakon, Kengo Tachibana, Hirokazu Iida
Abstract. Time-domain astronomy is important in the field of modern astronomy, and monitoring observations in the mid-infrared region with 1% photometric accuracy to study the variables and transients is becoming essential. The non-uniformity of the sensitivity caused by the optical characteristics of instruments and differences in the response curves of individual detector pixels degrade photometric accuracy. Therefore, to achieve 1% photometric accuracy, a flat-field correction for the non-uniformity with an accuracy of better than 1% is required. We developed a flat calibration unit (FCU) consisting of a silicon lens, a blackbody source, and two flat folding mirrors. We conducted proof-of-concept tests of the FCU by measuring the accuracy and stability of flat frames obtained using the FCU. The accuracies of the flat frames were 0.23% at 7.7 μm, 0.43% at 9.6 μm, 0.34% at 11.5 μm, and 0.84% at 20.9 μm, which are sufficient to achieve 1% photometric accuracy. The flat frames obtained using the FCU were stable over a period of 29 h within the accuracies of 0.13% at 7.7 μm, 0.12% at 9.6 μm, 0.22% at 11.5 μm, and 0.52% at 20.9 μm, indicating that it is sufficient to obtain flat frames once per night.
{"title":"Development of a flat calibration unit for accurate flat fielding in the mid-infrared region","authors":"Akira C. Naruse, T. Kamizuka, T. Miyata, S. Sako, R. Ohsawa, K. Asano, Atsushi Nishimura, I. Sakon, Kengo Tachibana, Hirokazu Iida","doi":"10.1117/1.JATIS.9.3.038004","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.038004","url":null,"abstract":"Abstract. Time-domain astronomy is important in the field of modern astronomy, and monitoring observations in the mid-infrared region with 1% photometric accuracy to study the variables and transients is becoming essential. The non-uniformity of the sensitivity caused by the optical characteristics of instruments and differences in the response curves of individual detector pixels degrade photometric accuracy. Therefore, to achieve 1% photometric accuracy, a flat-field correction for the non-uniformity with an accuracy of better than 1% is required. We developed a flat calibration unit (FCU) consisting of a silicon lens, a blackbody source, and two flat folding mirrors. We conducted proof-of-concept tests of the FCU by measuring the accuracy and stability of flat frames obtained using the FCU. The accuracies of the flat frames were 0.23% at 7.7 μm, 0.43% at 9.6 μm, 0.34% at 11.5 μm, and 0.84% at 20.9 μm, which are sufficient to achieve 1% photometric accuracy. The flat frames obtained using the FCU were stable over a period of 29 h within the accuracies of 0.13% at 7.7 μm, 0.12% at 9.6 μm, 0.22% at 11.5 μm, and 0.52% at 20.9 μm, indicating that it is sufficient to obtain flat frames once per night.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87333509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-01DOI: 10.1117/1.JATIS.9.3.038002
A. Ratheesh, J. Rankin, E. Costa, E. Del Monte, A. Di Marco, S. Fabiani, F. La Monaca, F. Muleri, A. Rubini, P. Soffitta, L. Baldini, M. Minuti, M. Pinchera, C. Sgro’
Abstract. In this work, we measured the polarization properties of the X-rays emitted from the X-ray tubes, which were used during the calibration of the instrument onboard Imaging X-ray Polarimetry Explorer (IXPE). X-ray tubes are used as a source of unpolarized X-rays to calibrate the response of the gas pixel detectors to unpolarized radiation. However, even though the characteristic fluorescent emission lines are unpolarized, continuum bremsstrahlung emission can be polarized based on the geometry of the accelerated electrons and emitted photons. Hence, characterizing the contribution of polarized X-rays from bremsstrahlung emission is of interest, also for future measurements. We find that, when accelerated electrons are parallel to the emitted photons, the bremsstrahlung emission is unpolarized, and when they are perpendicular, the polarization increases with energy, as expected from the theoretical predictions. A comparison with the theoretical predictions is also shown.
{"title":"Polarization properties of X-ray tubes used for Imaging X-ray Polarimetry Explorer calibration","authors":"A. Ratheesh, J. Rankin, E. Costa, E. Del Monte, A. Di Marco, S. Fabiani, F. La Monaca, F. Muleri, A. Rubini, P. Soffitta, L. Baldini, M. Minuti, M. Pinchera, C. Sgro’","doi":"10.1117/1.JATIS.9.3.038002","DOIUrl":"https://doi.org/10.1117/1.JATIS.9.3.038002","url":null,"abstract":"Abstract. In this work, we measured the polarization properties of the X-rays emitted from the X-ray tubes, which were used during the calibration of the instrument onboard Imaging X-ray Polarimetry Explorer (IXPE). X-ray tubes are used as a source of unpolarized X-rays to calibrate the response of the gas pixel detectors to unpolarized radiation. However, even though the characteristic fluorescent emission lines are unpolarized, continuum bremsstrahlung emission can be polarized based on the geometry of the accelerated electrons and emitted photons. Hence, characterizing the contribution of polarized X-rays from bremsstrahlung emission is of interest, also for future measurements. We find that, when accelerated electrons are parallel to the emitted photons, the bremsstrahlung emission is unpolarized, and when they are perpendicular, the polarization increases with energy, as expected from the theoretical predictions. A comparison with the theoretical predictions is also shown.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88189194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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