This work describes the instrumental error budget for space-based measurements of the absolute flux of the sky synchrotron spectrum at frequencies below the ionospheric cutoff (<20 MHz). We focus on an architecture using electrically short dipoles onboard a small satellite. The error budget combines the contributions of the dipole dimensions, plasma noise, stray capacitance, and front-end amplifier input impedance. We treat the errors using both a Monte Carlo error propagation model and an analytical method. This error budget can be applied to a variety of experiments and used to ultimately improve the sensing capabilities of space-based electrically short dipole instruments. The impact of individual uncertainty components, particularly stray capacitance, is explored in more detail.
{"title":"An Instrument Error Budget for Space-Based Absolute Flux Measurements of the Sky Synchrotron Spectrum Below 20 MHz","authors":"Julie Rolla, Andrew Romero-Wolf, Joseph Lazio","doi":"arxiv-2409.06510","DOIUrl":"https://doi.org/arxiv-2409.06510","url":null,"abstract":"This work describes the instrumental error budget for space-based\u0000measurements of the absolute flux of the sky synchrotron spectrum at\u0000frequencies below the ionospheric cutoff (<20 MHz). We focus on an architecture\u0000using electrically short dipoles onboard a small satellite. The error budget\u0000combines the contributions of the dipole dimensions, plasma noise, stray\u0000capacitance, and front-end amplifier input impedance. We treat the errors using\u0000both a Monte Carlo error propagation model and an analytical method. This error\u0000budget can be applied to a variety of experiments and used to ultimately\u0000improve the sensing capabilities of space-based electrically short dipole\u0000instruments. The impact of individual uncertainty components, particularly\u0000stray capacitance, is explored in more detail.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rodrigo Freundt, Yaqiong Li, Doug Henke, Jason Austermann, James R. Burgoyne, Scott Chapman, Steve K. Choi, Cody J. Duell, Zach Huber, Michael Niemack, Thomas Nikola, Lawrence Lin, Dominik A. Riechers, Gordon Stacey, Anna K. Vaskuri, Eve M. Vavagiakis, Jordan Wheeler, Bugao Zou
The Epoch of Reionization Spectrometer (EoR-Spec) is an upcoming Line Intensity Mapping (LIM) instrument designed to study the evolution of the early universe (z = 3.5 to 8) by probing the redshifted [CII] 158 $mu$m fine-structure line from aggregates of galaxies. The [CII] emission is an excellent tracer of star formation since it is the dominant cooling line from neutral gas heated by OB star light and thus can be used to probe the reionization of the early Universe due to star formation. EoR-Spec will be deployed on Prime-Cam, a modular direct-detection receiver for the 6-meter Fred Young Submillimeter Telescope (FYST), currently under construction by CPI Vertex Antennentechnik GmbH and to be installed near the summit of Cerro Chajnantor in the Atacama Desert. This instrument features an image plane populated with more than 6500 Microwave Kinetic Inductance Detectors (MKIDs) that are illuminated by a 4-lens optical design with a cryogenic, scanning Fabry-Perot Interferometer (FPI) at the pupil of the optical system. The FPI is designed to provide a spectral resolving power of $Rsim100$ over the full spectral range of 210--420 GHz. EoR-Spec will tomographically survey the E-COSMOS and E-CDFS fields with a depth of about 4000 hours over a 5 year period. Here we give an update on EoR-Spec's final mechanical/optical design and the current status of fabrication, characterization and testing towards first light in 2026.
{"title":"CCAT: A status update on the EoR-Spec instrument module for Prime-Cam","authors":"Rodrigo Freundt, Yaqiong Li, Doug Henke, Jason Austermann, James R. Burgoyne, Scott Chapman, Steve K. Choi, Cody J. Duell, Zach Huber, Michael Niemack, Thomas Nikola, Lawrence Lin, Dominik A. Riechers, Gordon Stacey, Anna K. Vaskuri, Eve M. Vavagiakis, Jordan Wheeler, Bugao Zou","doi":"arxiv-2409.05979","DOIUrl":"https://doi.org/arxiv-2409.05979","url":null,"abstract":"The Epoch of Reionization Spectrometer (EoR-Spec) is an upcoming Line\u0000Intensity Mapping (LIM) instrument designed to study the evolution of the early\u0000universe (z = 3.5 to 8) by probing the redshifted [CII] 158 $mu$m\u0000fine-structure line from aggregates of galaxies. The [CII] emission is an\u0000excellent tracer of star formation since it is the dominant cooling line from\u0000neutral gas heated by OB star light and thus can be used to probe the\u0000reionization of the early Universe due to star formation. EoR-Spec will be\u0000deployed on Prime-Cam, a modular direct-detection receiver for the 6-meter Fred\u0000Young Submillimeter Telescope (FYST), currently under construction by CPI\u0000Vertex Antennentechnik GmbH and to be installed near the summit of Cerro\u0000Chajnantor in the Atacama Desert. This instrument features an image plane\u0000populated with more than 6500 Microwave Kinetic Inductance Detectors (MKIDs)\u0000that are illuminated by a 4-lens optical design with a cryogenic, scanning\u0000Fabry-Perot Interferometer (FPI) at the pupil of the optical system. The FPI is\u0000designed to provide a spectral resolving power of $Rsim100$ over the full\u0000spectral range of 210--420 GHz. EoR-Spec will tomographically survey the\u0000E-COSMOS and E-CDFS fields with a depth of about 4000 hours over a 5 year\u0000period. Here we give an update on EoR-Spec's final mechanical/optical design\u0000and the current status of fabrication, characterization and testing towards\u0000first light in 2026.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joseph R. Masiero, Tyler Linder, Amy Mainzer, Dar W. Dahlen, Yuna G. Kwon
NEO Surveyor will detect asteroids and comets using mid-infrared thermal emission, however ground-based followup resources will require knowledge of the expected visible light brightness in order to plan characterization observations. Here we describe the range of visual-to-infrared colors that the NEOs detected by Surveyor will span, and demonstrate that for objects that have no previously reported Visual band observations, estimates of the Johnson Visual-band brightness based on infrared flux alone will have significant uncertainty. Incidental or targeted photometric followup of objects discovered by Surveyor enables predictions of the fraction of reflected light visible and near-infrared wavelengths, supporting additional detailed characterization.
{"title":"Visual-band brightnesses of Near Earth Objects that will be discovered in the infrared by NEO Surveyor","authors":"Joseph R. Masiero, Tyler Linder, Amy Mainzer, Dar W. Dahlen, Yuna G. Kwon","doi":"arxiv-2409.05753","DOIUrl":"https://doi.org/arxiv-2409.05753","url":null,"abstract":"NEO Surveyor will detect asteroids and comets using mid-infrared thermal\u0000emission, however ground-based followup resources will require knowledge of the\u0000expected visible light brightness in order to plan characterization\u0000observations. Here we describe the range of visual-to-infrared colors that the\u0000NEOs detected by Surveyor will span, and demonstrate that for objects that have\u0000no previously reported Visual band observations, estimates of the Johnson\u0000Visual-band brightness based on infrared flux alone will have significant\u0000uncertainty. Incidental or targeted photometric followup of objects discovered\u0000by Surveyor enables predictions of the fraction of reflected light visible and\u0000near-infrared wavelengths, supporting additional detailed characterization.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study introduces PI-AstroDeconv, a physics-informed semi-supervised learning method specifically designed for removing beam effects in astronomical telescope observation systems. The method utilizes an encoder-decoder network architecture and combines the telescope's point spread function or beam as prior information, while integrating fast Fourier transform accelerated convolution techniques into the deep learning network. This enables effective removal of beam effects from astronomical observation images. PI-AstroDeconv can handle multiple PSFs or beams, tolerate imprecise measurements to some extent, and significantly improve the efficiency and accuracy of image deconvolution. Therefore, this algorithm is particularly suitable for astronomical data processing that does not rely on annotated data. To validate the reliability of the algorithm, we used the SKA Science Data Challenge 3a datasets and compared it with the CLEAN deconvolution method at the 2-D matter power spectrum level. The results demonstrate that our algorithm not only restores details and reduces blurriness in celestial images at the pixel level but also more accurately recovers the true neutral hydrogen power spectrum at the matter power spectrum level.
{"title":"Application of Physics-Informed Neural Networks in Removing Telescope Beam Effects","authors":"Shulei Ni, Yisheng Qiu, Yunchuan Chen, Zihao Song, Hao Chen, Xuejian Jiang, Donghui Quan, Huaxi Chen","doi":"arxiv-2409.05718","DOIUrl":"https://doi.org/arxiv-2409.05718","url":null,"abstract":"This study introduces PI-AstroDeconv, a physics-informed semi-supervised\u0000learning method specifically designed for removing beam effects in astronomical\u0000telescope observation systems. The method utilizes an encoder-decoder network\u0000architecture and combines the telescope's point spread function or beam as\u0000prior information, while integrating fast Fourier transform accelerated\u0000convolution techniques into the deep learning network. This enables effective\u0000removal of beam effects from astronomical observation images. PI-AstroDeconv\u0000can handle multiple PSFs or beams, tolerate imprecise measurements to some\u0000extent, and significantly improve the efficiency and accuracy of image\u0000deconvolution. Therefore, this algorithm is particularly suitable for\u0000astronomical data processing that does not rely on annotated data. To validate\u0000the reliability of the algorithm, we used the SKA Science Data Challenge 3a\u0000datasets and compared it with the CLEAN deconvolution method at the 2-D matter\u0000power spectrum level. The results demonstrate that our algorithm not only\u0000restores details and reduces blurriness in celestial images at the pixel level\u0000but also more accurately recovers the true neutral hydrogen power spectrum at\u0000the matter power spectrum level.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
GHOST is a newly operational optical fiber-fed high-resolution spectrograph at the Gemini South 8.1m telescope. It currently offers the choice of two resolution modes captured by one (or two) input IFUs with a FOV of 1.2'' and a spectral resolving power of 56,000 and 76,000 for the unbinned CCDs. At the high-resolution mode, one can also instigate a simultaneous ThXe calibration lamp, which along with a simultaneous pseudo-slit profile constructed from reformatting the input IFU image will allow for precision radial velocity measurements. Here we talk about the proposed roadmap towards full queue operations, potential upgrades, and the error terms contributing to the final on-sky RV precision, which is estimated to be in the 1-10 m s$^{-1}$ range.
{"title":"Roadmap of GHOST@Gemini's Precision Radial Velocity Mode","authors":"Venu M. Kalari, Andreas Seifahrt, Ruben Diaz","doi":"arxiv-2409.05656","DOIUrl":"https://doi.org/arxiv-2409.05656","url":null,"abstract":"GHOST is a newly operational optical fiber-fed high-resolution spectrograph\u0000at the Gemini South 8.1m telescope. It currently offers the choice of two\u0000resolution modes captured by one (or two) input IFUs with a FOV of 1.2'' and a\u0000spectral resolving power of 56,000 and 76,000 for the unbinned CCDs. At the\u0000high-resolution mode, one can also instigate a simultaneous ThXe calibration\u0000lamp, which along with a simultaneous pseudo-slit profile constructed from\u0000reformatting the input IFU image will allow for precision radial velocity\u0000measurements. Here we talk about the proposed roadmap towards full queue\u0000operations, potential upgrades, and the error terms contributing to the final\u0000on-sky RV precision, which is estimated to be in the 1-10 m s$^{-1}$ range.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"293 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ana Martins, Melissa Lopez, Quirijn Meijer, Gregory Baltus, Marc van der Sluys, Chris Van Den Broeck, Sarah Caudill
The detection of gravitational waves (GWs) from binary neutron stars (BNSs) with possible telescope follow-ups opens a window to ground-breaking discoveries in the field of multi-messenger astronomy. With the improved sensitivity of current and future GW detectors, more BNS detections are expected in the future. Therefore, enhancing low-latency GW search algorithms to achieve rapid speed, high accuracy, and low computational cost is essential. One innovative solution to reduce latency is the use of machine learning (ML) methods embedded in field-programmable gate arrays (FPGAs). In this work, we present a novel texttt{WaveNet}-based method, leveraging the state-of-the-art ML model, to produce early-warning alerts for BNS systems. Using simulated GW signals embedded in Gaussian noise from the Advanced LIGO and Advanced Virgo detectors' third observing run (O3) as a proof-of-concept dataset, we demonstrate significant performance improvements. Compared to the current leading ML-based early-warning system, our approach enhances detection accuracy from 66.81% to 76.22% at a 1% false alarm probability. Furthermore, we evaluate the time, energy, and economical cost of our model across CPU, GPU, and FPGA platforms, showcasing its potential for deployment in real-time gravitational wave detection pipelines.
{"title":"Improving Early Detection of Gravitational Waves from Binary Neutron Stars Using CNNs and FPGAs","authors":"Ana Martins, Melissa Lopez, Quirijn Meijer, Gregory Baltus, Marc van der Sluys, Chris Van Den Broeck, Sarah Caudill","doi":"arxiv-2409.05068","DOIUrl":"https://doi.org/arxiv-2409.05068","url":null,"abstract":"The detection of gravitational waves (GWs) from binary neutron stars (BNSs)\u0000with possible telescope follow-ups opens a window to ground-breaking\u0000discoveries in the field of multi-messenger astronomy. With the improved\u0000sensitivity of current and future GW detectors, more BNS detections are\u0000expected in the future. Therefore, enhancing low-latency GW search algorithms\u0000to achieve rapid speed, high accuracy, and low computational cost is essential.\u0000One innovative solution to reduce latency is the use of machine learning (ML)\u0000methods embedded in field-programmable gate arrays (FPGAs). In this work, we\u0000present a novel texttt{WaveNet}-based method, leveraging the state-of-the-art\u0000ML model, to produce early-warning alerts for BNS systems. Using simulated GW\u0000signals embedded in Gaussian noise from the Advanced LIGO and Advanced Virgo\u0000detectors' third observing run (O3) as a proof-of-concept dataset, we\u0000demonstrate significant performance improvements. Compared to the current\u0000leading ML-based early-warning system, our approach enhances detection accuracy\u0000from 66.81% to 76.22% at a 1% false alarm probability. Furthermore, we\u0000evaluate the time, energy, and economical cost of our model across CPU, GPU,\u0000and FPGA platforms, showcasing its potential for deployment in real-time\u0000gravitational wave detection pipelines.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vincent Deo, Sebastien Vievard, Manon Lallement, Miles Lucas, Elsa Huby, Kyohoon Ahn, Olivier Guyon, Julien Lozi, Harry-Dean Kenchington-Goldsmith, Sylvestre Lacour, Guillermo Martin, Barnaby Norris, Guy Perrin, Garima Singh, Peter Tuthill
The petaling effect, induced by pupil fragmentation from the telescope spider, drastically affects the performance of high contrast instruments by inducing core splitting on the PSF. Differential piston/tip/tilt aberrations within each optically separated fragment of the pupil are poorly measured by commonly used Adaptive Optics (AO) systems. We here pursue a design of dedicated low-order wavefront sensor -- or petalometers -- to complement the main AO. Interferometric devices sense differential aberrations between fragments with optimal sensitivity; their weakness though is their limitation to wrapped phase measurements. We show that by combining multiple spectral channels, we increase the capture range for petaling aberrations beyond several microns, enough to disambiguate one-wave wrapping errors made by the main AO system. We propose here to implement a petalometer from the multi-wavelength imaging mode of the VAMPIRES visible-light instrument, deployed on SCExAO at the Subaru Telescope. The interferometric measurements obtained in four spectral channels through a 7 hole non-redundant mask allow us to effiiently reconstruct diffierential piston between pupil petals.
{"title":"Spectral interferometric wavefront sensing: a solution for petalometry at Subaru/SCExAO","authors":"Vincent Deo, Sebastien Vievard, Manon Lallement, Miles Lucas, Elsa Huby, Kyohoon Ahn, Olivier Guyon, Julien Lozi, Harry-Dean Kenchington-Goldsmith, Sylvestre Lacour, Guillermo Martin, Barnaby Norris, Guy Perrin, Garima Singh, Peter Tuthill","doi":"arxiv-2409.05246","DOIUrl":"https://doi.org/arxiv-2409.05246","url":null,"abstract":"The petaling effect, induced by pupil fragmentation from the telescope\u0000spider, drastically affects the performance of high contrast instruments by\u0000inducing core splitting on the PSF. Differential piston/tip/tilt aberrations\u0000within each optically separated fragment of the pupil are poorly measured by\u0000commonly used Adaptive Optics (AO) systems. We here pursue a design of\u0000dedicated low-order wavefront sensor -- or petalometers -- to complement the\u0000main AO. Interferometric devices sense differential aberrations between\u0000fragments with optimal sensitivity; their weakness though is their limitation\u0000to wrapped phase measurements. We show that by combining multiple spectral\u0000channels, we increase the capture range for petaling aberrations beyond several\u0000microns, enough to disambiguate one-wave wrapping errors made by the main AO\u0000system. We propose here to implement a petalometer from the multi-wavelength\u0000imaging mode of the VAMPIRES visible-light instrument, deployed on SCExAO at\u0000the Subaru Telescope. The interferometric measurements obtained in four\u0000spectral channels through a 7 hole non-redundant mask allow us to effiiently\u0000reconstruct diffierential piston between pupil petals.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"424 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mark Hammond, Claire Marie Guimond, Tim Lichtenberg, Harrison Nicholls, Chloe Fisher, Rafael Luque, Tobias G. Meier, Jake Taylor, Quentin Changeat, Lisa Dang, Oliver Herbort, Johanna Teske
The distribution of different types of atmospheres and surfaces on rocky planets is one of the major questions in exoplanet astronomy, but there are currently no published unambiguous detections of atmospheres on any rocky exoplanets. The MIRI instrument on JWST can measure thermal emission from tidally locked rocky exoplanets orbiting small, cool stars. This emission is a function of their surface and atmospheric properties, potentially allowing the detection of atmospheres. One technique is to measure day-side emission to search for lower thermal emission than expected for a black-body planet due to atmospheric absorption features. Another technique is to measure phase curves of thermal emission to search for night-side emission due to atmospheric heat redistribution. In this work we compare strategies for detecting atmospheres on rocky exoplanets using these techniques. We simulate secondary eclipse and phase curve observations in the MIRI F1500W and F1280W filters, for a range of surfaces and atmospheres on thirty exoplanets selected for their F1500W signal-to-noise ratio. Our results show that secondary eclipse observations are highly degenerate between surfaces and atmospheres, given the wide range of potential surface albedos. We also show that thick atmospheres can support emission consistent with a black-body planet in these filters. These two results make it difficult to unambiguously detect or rule out atmospheres using their photometric day-side emission, except in a subset of CO$_{2}$-dominated atmospheres. We suggest that an F1500W phase curve could instead be observed for a similar sample of planets, allowing the unambiguous detection of atmospheres by night-side emission.
{"title":"Reliable Detections of Atmospheres on Rocky Exoplanets with Photometric JWST Phase Curves","authors":"Mark Hammond, Claire Marie Guimond, Tim Lichtenberg, Harrison Nicholls, Chloe Fisher, Rafael Luque, Tobias G. Meier, Jake Taylor, Quentin Changeat, Lisa Dang, Oliver Herbort, Johanna Teske","doi":"arxiv-2409.04386","DOIUrl":"https://doi.org/arxiv-2409.04386","url":null,"abstract":"The distribution of different types of atmospheres and surfaces on rocky\u0000planets is one of the major questions in exoplanet astronomy, but there are\u0000currently no published unambiguous detections of atmospheres on any rocky\u0000exoplanets. The MIRI instrument on JWST can measure thermal emission from\u0000tidally locked rocky exoplanets orbiting small, cool stars. This emission is a\u0000function of their surface and atmospheric properties, potentially allowing the\u0000detection of atmospheres. One technique is to measure day-side emission to\u0000search for lower thermal emission than expected for a black-body planet due to\u0000atmospheric absorption features. Another technique is to measure phase curves\u0000of thermal emission to search for night-side emission due to atmospheric heat\u0000redistribution. In this work we compare strategies for detecting atmospheres on\u0000rocky exoplanets using these techniques. We simulate secondary eclipse and\u0000phase curve observations in the MIRI F1500W and F1280W filters, for a range of\u0000surfaces and atmospheres on thirty exoplanets selected for their F1500W\u0000signal-to-noise ratio. Our results show that secondary eclipse observations are\u0000highly degenerate between surfaces and atmospheres, given the wide range of\u0000potential surface albedos. We also show that thick atmospheres can support\u0000emission consistent with a black-body planet in these filters. These two\u0000results make it difficult to unambiguously detect or rule out atmospheres using\u0000their photometric day-side emission, except in a subset of CO$_{2}$-dominated\u0000atmospheres. We suggest that an F1500W phase curve could instead be observed\u0000for a similar sample of planets, allowing the unambiguous detection of\u0000atmospheres by night-side emission.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The RISTRETTO instrument, a proposed visible high-contrast, high-resolution spectrograph for the VLT, has the primary science goal of detecting reflected light from nearby exoplanets and characterizing their atmospheres. Specifically, it aims to atmospherically characterize Proxima b, our closest temperate rocky exoplanet, located $37 mas$ from its host star, corresponding to $2lambda/D$ at $lambda=750 nm$. To achieve this goal, a raw contrast of less than $10^{-4}$ at $2lambda/D$ and a Strehl ratio greater than 70% are required, necessitating an extreme adaptive optics system (XAO) for the spectrograph. To meet the performance requirements for RISTRETTO, high sensitivity to low-order wavefront aberrations and petal modes is essential. Therefore, unmodulated Pyramid wavefront sensors (PWFS) and Zernike wavefront sensors (ZWFS) are under consideration. However, these sensors exhibit non-linearities and have a limited dynamic range, requiring different strategies to optimize their performance. The dynamic range of the sensors increases at longer wavelengths. Thus, in this study, we compare the performance of the 3-sided unmodulated PWFS, the 4-sided unmodulated PWFS, and the Zerniike WFS at different wavelengths in the visible and near-infrared regime.
{"title":"RISTRETTO: a comparative performance analysis of the unmodulated Pyramid wavefront sensor and the Zernike wavefront sensor","authors":"Muskan Shinde, Nicolas Blind, Christophe Lovis","doi":"arxiv-2409.04255","DOIUrl":"https://doi.org/arxiv-2409.04255","url":null,"abstract":"The RISTRETTO instrument, a proposed visible high-contrast, high-resolution\u0000spectrograph for the VLT, has the primary science goal of detecting reflected\u0000light from nearby exoplanets and characterizing their atmospheres.\u0000Specifically, it aims to atmospherically characterize Proxima b, our closest\u0000temperate rocky exoplanet, located $37 mas$ from its host star, corresponding\u0000to $2lambda/D$ at $lambda=750 nm$. To achieve this goal, a raw contrast of\u0000less than $10^{-4}$ at $2lambda/D$ and a Strehl ratio greater than 70% are\u0000required, necessitating an extreme adaptive optics system (XAO) for the\u0000spectrograph. To meet the performance requirements for RISTRETTO, high\u0000sensitivity to low-order wavefront aberrations and petal modes is essential.\u0000Therefore, unmodulated Pyramid wavefront sensors (PWFS) and Zernike wavefront\u0000sensors (ZWFS) are under consideration. However, these sensors exhibit\u0000non-linearities and have a limited dynamic range, requiring different\u0000strategies to optimize their performance. The dynamic range of the sensors\u0000increases at longer wavelengths. Thus, in this study, we compare the\u0000performance of the 3-sided unmodulated PWFS, the 4-sided unmodulated PWFS, and\u0000the Zerniike WFS at different wavelengths in the visible and near-infrared\u0000regime.","PeriodicalId":501163,"journal":{"name":"arXiv - PHYS - Instrumentation and Methods for Astrophysics","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muskan Shinde, Jana Anouk Baron, Nicolas Blind, Janis Hagelberg, Christophe Lovis, François Wildi, Damien Ségransan
In the near-infrared wavelength regime, atmospheric turbulence fluctuates at a scale of a few milliseconds, and its precise control requires the use of extreme adaptive optics (XAO) systems equipped with fast and sensitive detectors operating at kHz speeds. The C-RED One cameras developed by First Light Imaging (FLI), based on SAPHIRA detectors made of HgCdTe e-APD array sensitive to 0.8-2.5 $mu$m light, featuring a 320x256 pixels with 24 $mu$m pitch, offering sub-electron readout noise and the ability to read subarrays, at frame-rates of up to few 10-kHz, are state-of-the-art for XAO wavefront sensing. The Observatory of Geneva purchased two C-RED One cameras identified as necessary for RISTRETTO (a proposed high-contrast high-resolution spectrograph for the VLT) and SAXO+ (an upgrade of the VLT/SPHERE XAO system) projects. We present a comprehensive characterization and comparative analysis of both the cameras. We present test results examining key noise contributors, including readout noise, detector bias, etc. And we also study their temporal variability. Additionally, we assess the conversion gain and the avalanche gain calibration of the detector. We also study the evolution some of these parameters over time.
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