Owens Valley Solar Arrays: Difference between revisions

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[[File:Eovsa1.png|border|text-top|800px]]
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[[File:OVRO-LWA1.png|border|text-top|800px]]-->
<big>Owens Valley Solar Arrays (OVSA) is a university-led radio facility dedicated to solar astrophysics and space weather research. Located in the Owens Valley Radio Observatory (OVRO) near Big Pine, California, the operations of OVSA include the Expanded Owens Valley Solar Array (EOVSA) observing in the microwave regime (1-18 GHz), as well as the solar and space weather aspects of the newly commissioned Long Wavelength Array at the Owens Valley Radio Observatory (OVRO-LWA), which observes in the meter-decameter wavelength regime (13-87 MHz). Please refer to [https://ovsa.njit.edu/ our home page] for more general descriptions of the facility. This wiki serves as the site for OVSA documentation.  </big>


<big>[http://ovsa.njit.edu/ EOVSA] (Expanded Owens Valley Solar Array) is a solar-dedicated radio interferometer operated by the New Jersey Institute of Technology and serving as a '''National Science Foundation Geospace Facility'''. [[File:NSF.jpg|70px]]
{| class="wikitable" style="border: none;"
<pre>Operation of EOVSA is supported by the National Science Foundation under Grant No. AGS-2130832. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. </pre>
|-
This wiki serves as the site for EOVSA documentation. </big>
| ''Operation of OVSA is supported by the National Science Foundation under Grant AGS-2436999. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.''
| [[File:NSF.jpg|70px]]
|}


[[File:OVRO-LWA1.png|border|text-top|800px]]
== Latest OVSA Science Highlights ==
[[OVSA Science Highlight No. 6: Detection of Radio Gyroresonance Emission from a CME]]
[[File:cme_20240309.jpeg|left|100px]]
[https://arxiv.org/abs/2509.16453 This study] reports the first possible detection of thermal gyroresonance emission from a CME. This breakthrough offers a new potential method for measuring the magnetic field of CMEs. [Contributed by Surajit Mondal (New Jersey Institute of Technology); Edited by B. Chen. Posted on September 26, 2025.]


<big>OVRO-LWA (Owens Valley Radio Observatory Long Wavelength Array) is an all-sky imager that has a new solar-dedicated spectroscopic imaging mode. OVRO-LWA is a multi-institutional collaboration led by Caltech. NJIT Solar Radio Group is leading its solar-mode development and science. At the bottom of this page are new links for that facility.  </big>
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== Latest [[OVSA Science Highlights]] ==
[[OVSA Science Highlight No. 5: Is CME's Magnetic Flux Conserved?]]
[[File:cme_mfr.jpeg|left|100px]]
According to [https://iopscience.iop.org/article/10.3847/2041-8213/adfa71 this study], the answer is "probably yes." The conclusion is made by using ultrabroadband radio imaging spectroscopy to derive the magnetic field evolution of an erupting CME from the low to middle corona.  [Contributed by Xingyao Chen (New Jersey Institute of Technology); Edited by B. Chen. Posted on September 19, 2025.]
 
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[[OVSA Science Highlight No. 4: When the Sun Meets the Crab]]
[[File:crab_solar_conjunction.jpeg|left|100px]]
When the Crab Nebula passes behind the Sun each June, radio telescopes can catch its distorted signals, providing a rare way to probe turbulence in the Sun’s extended atmosphere out to more than 10 solar radii. [Contributed by Peijin Zhang (New Jersey Institute of Technology); Edited by B. Chen. Posted on September 11, 2025.]
 
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[[OVSA Science Highlight No. 3: The First EOVSA "Cold" Solar Flare]]
[[File:cold_flare.jpeg|left|100px]]
[https://iopscience.iop.org/article/10.3847/1538-4357/ade983 This study] takes advantage of EOVSA's microwave imaging spectroscopy capability and multi-wavelength observations to measure the coronal magnetic field and track the flare energy partitioning. The results show ample magnetic free energy to drive efficient electron acceleration, with the energy deposition of nonthermal electrons alone accounting for the observed thermal response, reinforcing cold flares as clean cases of particle-driven heating. [Contributed by Gregory Fleishman (New Jersey Institute of Technology); Edited by B. Chen. Posted on August 20, 2025.]
 
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[[OVSA Science Highlight No. 2: Two Phases of Impulsive SEP Acceleration]]
[[File:SEP_illustration_gemini.jpeg|left|100px]]
[https://iopscience.iop.org/article/10.3847/1538-4357/adbdd0 M. Wang et al.] analyze a solar energetic particle (SEP) event associated with an eruptive X-class flare and found two distinct impulsive SEP acceleration phases. They are suggested to link to different magnetic reconnection regimes during the eruption, which govern the timing and energy of particles released into interplanetary space. [Contributed by Meiqi Wang (New Jersey Institute of Technology); Edited by B. Chen. Posted on August 19, 2025.]
 
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[[OVSA Science Highlight No. 1: Microwave Precursor of a Major Solar Eruption]]
[[OVSA Science Highlight No. 1: Microwave Precursor of a Major Solar Eruption]]
[[File:solar_eruption_nasa.jpeg|left|100px]]
[[File:solar_eruption_nasa.jpeg|left|100px]]
A study by [https://iopscience.iop.org/article/10.3847/2041-8213/adf063 Kou et al.] presents the first spatially resolved microwave imaging spectroscopy of the precursor phase of a major solar eruption. The findings reveal that thermal electron emissions dominate during the slow-rise phase, supporting a scenario of moderate magnetic reconnection prior to the flare’s impulsive onset. [Contributed by Y. Kou; Edited by B. Chen. Posted on August 2, 2025.]
A study by [https://iopscience.iop.org/article/10.3847/2041-8213/adf063 Y. Kou et al.] presents the first spatially resolved microwave imaging spectroscopy of the precursor phase of a major solar eruption. The findings reveal that thermal electron emissions dominate during the slow-rise phase, supporting a scenario of moderate magnetic reconnection prior to the flare’s impulsive onset. [Contributed by Yuankun Kou (Nanjing University); Edited by B. Chen. Posted on August 2, 2025.]
 
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We welcome contributions at all times. Please refer to the [[OVSA Science Highlights]] page for author guidelines and a complete list of highlights.
 
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== OVSA Publications ==
== OVSA Publications ==
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* [https://ovsa.njit.edu/flarelist Query EOVSA Flare list]
* [https://ovsa.njit.edu/flarelist Query EOVSA Flare list]
* List of EOVSA flares in separate years: [[2025]], [[2024]], [[2023]], [[2022]], [[2021]], [[2020]], [[2019]], [[2017]]
* List of EOVSA flares in separate years: [[2025]], [[2024]], [[2023]], [[2022]], [[2021]], [[2020]], [[2019]], [[2017]]
== OVSA Observing ==
=== OVSA Weekly Observing Reports ===
* 2025
** Q4: [https://drive.google.com/file/d/1a_1yGUCdTDf5WXMy9I7vQHF_aYFGtMQT/view?usp=sharing 09/30-10/06], [https://drive.google.com/file/d/1rMHmGEVSgtjPIUp79eRQIx36Sh9Yim0S/view?usp=drive_link 10/07-10/13], [https://drive.google.com/file/d/1etXFQmVuUThH80lc61Fa3i8fCPwZ3OPM/view?usp=drive_link 10/14-10/20], [https://drive.google.com/file/d/12Wxmls11_mHTOTl_zdv5G1q1gomOsIXz/view?usp=drive_link 10/21-10/27], [https://drive.google.com/file/d/1pkNgGQh8ph6RvFsL1IR7ig8vN7tAlXS9/view?usp=drive_link 10/28-11/03], [https://drive.google.com/file/d/1PyGC6ixUoGwE1zMdm8ylIh1g51dAIHkQ/view?usp=drive_link 11/04-11/10], [https://drive.google.com/file/d/1s5b_hkhyL_eaHPbMAWUPq8XWpjD5Glln/view?usp=drive_link 11/11-11/17], [https://drive.google.com/file/d/1g_e-iWS-Qgs80d_xYzeEz_GKKc5P-Rax/view?usp=drive_link 11/18-11/24]
** Q3: [https://drive.google.com/file/d/1NLJpfehI7XiyNQc_9L69H9xrXn_LsCQM/view?usp=drive_link 08/26-09/01], [https://drive.google.com/file/d/1QiD9rk_DocXT1F3aRl3L49AAyaNaR9d1/view?usp=drive_link 09/02-09/08], [https://drive.google.com/file/d/1O2oGCAAnBX4YOmbWsra14zPxk2t7CQXn/view?usp=drive_link 09/09-09/15], [https://drive.google.com/file/d/1C-CF_OW8EqQflTPzceRzAyX3cRq8hKJ6/view?usp=drive_link 09/16-09/22], [https://drive.google.com/file/d/14ci0XpFu-kqPbcoPliUjnDNOHAoXi1vH/view?usp=drive_link 09/23-09/29]
=== OVSA Scientist on Duty ===
* Scientist on Duty (SoD): OVSA team members take turns and serve as a SoD to work with our onsite observatory staff on day-to-day observing. They are also responsible for monitoring solar activities and ensuring that the data we collect is of high quality.
* SoD observing logs ([https://drive.google.com/drive/folders/1q6-0Z9B0CPFutuTqzmeheEUSJM3tEL2o?usp=drive_link directory to all logs and weekly reports]):
** 2024: [https://docs.google.com/document/d/1QDWw5y4HpcE7CSpzXwftMqQT4FDgNJj-6fRrgWrqdug/edit?usp=sharing May (and before that)], [https://docs.google.com/document/d/1Rh2gYBV2E454xVYEv8jx5IXKd1N2Z05ns4dhI2XCE08/edit?usp=sharing June], [https://docs.google.com/document/d/1beUpp6rgwjqSxKbuHzXIR9hhPrGyi0j-SjtEIeav9Vg/edit?usp=sharing July], [https://docs.google.com/document/d/1pSzUXW5gd-4cZAR-gglTUVM_J2UHMa4wYJ2AzD4cdEo/edit?usp=sharing August], [https://docs.google.com/document/d/18pArAP0kRDhXHbty_y3TtrygmWkC2oLn-UD7njIpRIo/edit?usp=sharing September], [https://docs.google.com/document/d/1Qt6vhrqPAOG7W5Y_tLiod_QgNR1FDyzRxQcg6_oJQd4/edit?usp=sharing October], [https://docs.google.com/document/d/1pv9-Wne80FCrg0J5BkjOafmof_s3jlnc9HwyzWkIBfU/edit?usp=sharing November], [https://docs.google.com/document/d/1O5svOVwQZbUON1GMR_8nBR5LAL0M8RM2_zWW4oeBiLk/edit?usp=sharing December]
** 2025: [https://docs.google.com/document/d/1pUdSRyWgQa2py1PSLa3CKs_DDqL_SOgx6MMIp4cPnpk/edit?usp=sharing January], [https://docs.google.com/document/d/18cnIAaeM8UBiYPtsQn7g6TM8mjr57blSoY9l-6ShhwQ/edit?usp=sharing February], [https://docs.google.com/document/d/1k60i7nabWltnU38I7fGS2uq2-FUe5TMAKcM1BeLIRdY/edit?usp=sharing March], [https://docs.google.com/document/d/1CMaXBtA1ULNFbzuawYirP913A6dTa68cbYk2a7knirI/edit?usp=sharing April], [https://docs.google.com/document/d/13Kr8lYfFN9bzgFvCJi6nBUxbQHa3_eTgfjwaCUn3vCs/edit?tab=t.0 May], [https://docs.google.com/document/d/1ptGvQiB6SPgzJ-I6IgJ4bKK-3GPK-4LBpq7BG6sFPSg/edit?usp=sharing June], [https://docs.google.com/document/d/1XrOonOdwrkSDSWT2CwvzIaw7aRxBA4Sba1GCMRmkDZk/edit?usp=sharing July], [https://docs.google.com/document/d/1MzKkL8cPaBLNDOuws4U0ATuTN7kVaaeX4dUp0cga3vo/edit?usp=sharing August], [https://docs.google.com/document/d/14JHnHLZiDTqtK_cmaHgRevKksHuqijBQcMo1zcrz98k/edit?usp=sharing September], [https://docs.google.com/document/d/1RypoU6RtXVIdak_ESgabEK1Gp8XG7Tok2kHhPNZ3G4g/edit?usp=sharing October], [https://docs.google.com/document/d/1fQDS7mTQSnSfvTYozY6vXRrW_mleTf1vABTZhwYDKdw/edit?usp=sharing November]
* SoD instructions:
** Daily routines: see [https://docs.google.com/document/d/1_iGnMRRrvb85Z0vT8-LzgQmCOKDSATEuQ0vTsn2C-dc/edit?usp=sharing SoD Routines] for detailed instructions.
** Instructions for [[making quick-look flare spectrograms and movies]]
=== EOVSA Observing Log ===
[[2016 November]]; [[2016 December| December]]
[[2017 January]]; [[2017 February | February]]; [[2017 March | March]]; [[2017 April | April]]; [[2017 May | May]]; [[2017 June | June]];
[[2017 July | July]]; [[2017 August | August]]; [[2017 September | September]]; [[2017 October | October]]; [[2017 November | November]]; [[2017 December | December]]
[[2018 January]]; [[2018 February | February]]; [[2018 March | March]]; [[2018 April | April]]; [[2018 May | May]]; [[2018 June | June]];
[[2018 July | July]]; [[2018 August | August]]; [[2018 September | September]]; [[2018 October | October]]; [[2018 November | November]]; [[2018 December | December]]
[[2019 January]]; [[2019 February | February]]; [[2019 March | March]]; [[2019 April | April]]; [[2019 May | May]]; [[2019 June | June]];
[[2019 July | July]]; [[2019 August | August]]; [[2019 September | September]]; [[2019 October | October]]; [[2019 November | November]]; [[2019 December | December]]
[[2020 January]]; [[2020 February | February]]; [[2020 March | March]]; [[2020 April | April]]; [[2020 May | May]]; [[2020 June | June]];
[[2020 July | July]]; [[2020 August | August]]; [[2020 September | September]]; [[2020 October | October]]; [[2020 November | November]]; [[2020 December | December]]
[[2021 January]]; [[2021 February | February]]; [[2021 March | March]]; [[2021 April | April]]; [[2021 May | May]]; [[2021 June | June]];
[[2021 July | July]]; [[2021 August | August]]; [[2021 September | September]]; [[2021 October | October]]; [[2021 November | November]]; [[2021 December | December]]
[[2022 SQL Outage]]
[[2023 January]]; [[2023 February | February]]; [[2023 March | March]]; [[2023 April | April]]; [[2023 May | May]]; [[2023 June | June]];
[[2023 July | July]]; [[2023 August | August]]; [[2023 September | September]]; [[2023 October | October]]; [[2023 November | November]]; [[2023 December | December]]
[[2024 January]]; [[2024 February | February]]; [[2024 March | March]]; [[2024 April | April]]; [[2024 May |May]]; [[2024 June | June]]; [[2024 July | July]];  [[2024 August | August]];
[[2024 September | September]]; [[2024 October | October]]; [[2024 November | November]]; [[2024 December | December]]
[[2025 January]]; [[2025 February | February]]; [[2025 March | March]]; [[2025 April | April]]; [[2025 May |May]]; [[2025 June | June]]; [[2025 July | July]];  [[2025 August | August]];
[[2025 September | September]]; [[2025 October | October]]; [[2025 November | November]]; [[2025 December | December]]


== Using OVSA Data  ==
== Using OVSA Data  ==
* <big>[[EOVSA Data Products]]</big>: An introduction to standard EOVSA spectrogram and spectral image products with example scripts for reading and plotting.
* <big>[[EOVSA Data Products]]</big>: An introduction to standard EOVSA spectrogram and spectral image products with example scripts for reading and plotting.
* <big>[[EOVSA Data Policy]]</big>: Policy for using EOVSA data products.
* <big>[[OVRO-LWA Solar Data Products]]</big>: An introduction to OVRO-LWA solar spectrogram and spectral image products with example scripts for reading and plotting.
* <big>[[OVSA Data Policy]]</big>: Policy for using OVSA data products.
* <big>Analysis Software</big>: These are for in-depth use of EOVSA data (from calibrated visibilities) and tools for quantitative analysis.   
* <big>Analysis Software</big>: These are for in-depth use of EOVSA data (from calibrated visibilities) and tools for quantitative analysis.   
** [https://github.com/suncasa/suncasa SunCASA] A wrapper around [https://casa.nrao.edu/ CASA (the Common Astronomy Software Applications package)] for synthesis imaging and visualizing solar spectral imaging data. CASA is one of the leading software tool for "supporting the data post-processing needs of the next generation of radio astronomical telescopes such as ALMA and VLA", an international effort led by the [https://public.nrao.edu/ National Radio Astronomy Observatory]. The current version of CASA uses Python (2.7) interface. More information about CASA can be found on [https://casa.nrao.edu/ NRAO's CASA website ]. Note, CASA is available ONLY on UNIX-BASED PLATFORMS (and therefore, so is SunCASA).  
** [https://github.com/suncasa/suncasa SunCASA] A wrapper around [https://casa.nrao.edu/ CASA (the Common Astronomy Software Applications package)] for synthesis imaging and visualizing solar spectral imaging data. CASA is one of the leading software tool for "supporting the data post-processing needs of the next generation of radio astronomical telescopes such as ALMA and VLA", an international effort led by the [https://public.nrao.edu/ National Radio Astronomy Observatory]. The current version of CASA uses Python (2.7) interface. More information about CASA can be found on [https://casa.nrao.edu/ NRAO's CASA website ]. Note, CASA is available ONLY on UNIX-BASED PLATFORMS (and therefore, so is SunCASA).  
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* Python code [https://github.com/dgary50/eovsa Github repository]
* Python code [https://github.com/dgary50/eovsa Github repository]
* [[Python3 Code Installation]]
* [[Python3 Code Installation]]
== Using OVRO-LWA data ==
* <big>[[OVRO-LWA Data Products]]</big>: An introduction to standard OVRO-LWA spectrogram and spectral image products with example scripts for reading and plotting.
* <big>[[OVRO-LWA Data Policy]]</big>: Policy for using OVRO-LWA data products.
== EOVSA Observing Log ==
[[2016 November]]; [[2016 December| December]]
[[2017 January]]; [[2017 February | February]]; [[2017 March | March]]; [[2017 April | April]]; [[2017 May | May]]; [[2017 June | June]];
[[2017 July | July]]; [[2017 August | August]]; [[2017 September | September]]; [[2017 October | October]]; [[2017 November | November]]; [[2017 December | December]]
[[2018 January]]; [[2018 February | February]]; [[2018 March | March]]; [[2018 April | April]]; [[2018 May | May]]; [[2018 June | June]];
[[2018 July | July]]; [[2018 August | August]]; [[2018 September | September]]; [[2018 October | October]]; [[2018 November | November]]; [[2018 December | December]]
[[2019 January]]; [[2019 February | February]]; [[2019 March | March]]; [[2019 April | April]]; [[2019 May | May]]; [[2019 June | June]];
[[2019 July | July]]; [[2019 August | August]]; [[2019 September | September]]; [[2019 October | October]]; [[2019 November | November]]; [[2019 December | December]]
[[2020 January]]; [[2020 February | February]]; [[2020 March | March]]; [[2020 April | April]]; [[2020 May | May]]; [[2020 June | June]];
[[2020 July | July]]; [[2020 August | August]]; [[2020 September | September]]; [[2020 October | October]]; [[2020 November | November]]; [[2020 December | December]]
[[2021 January]]; [[2021 February | February]]; [[2021 March | March]]; [[2021 April | April]]; [[2021 May | May]]; [[2021 June | June]];
[[2021 July | July]]; [[2021 August | August]]; [[2021 September | September]]; [[2021 October | October]]; [[2021 November | November]]; [[2021 December | December]]
[[2022 SQL Outage]]
[[2023 January]]; [[2023 February | February]]; [[2023 March | March]]; [[2023 April | April]]; [[2023 May | May]]; [[2023 June | June]];
[[2023 July | July]]; [[2023 August | August]]; [[2023 September | September]]; [[2023 October | October]]; [[2023 November | November]]; [[2023 December | December]]
[[2024 January]]; [[2024 February | February]]; [[2024 March | March]]; [[2024 April | April]]; [[2024 May |May]]; [[2024 June | June]]; [[2024 July | July]];  [[2024 August | August]];
[[2024 September | September]]; [[2024 October | October]]; [[2024 November | November]]; [[2024 December | December]]
[[2025 January]]; [[2025 February | February]]; [[2025 March | March]]; [[2025 April | April]]; [[2025 May |May]]; [[2025 June | June]]; [[2025 July | July]];  [[2025 August | August]];
[[2025 September | September]]; [[2025 October | October]]; [[2025 November | November]]; [[2025 December | December]]
== OVSA Scientist on Duty ==
* Scientist on Duty (SoD): OVSA team members take turns and serve as a SoD to work with our onsite observatory staff on day-to-day observing. They are also responsible for monitoring solar activities and ensuring that the data we collect is of high quality.
* SoD observing logs ([https://drive.google.com/drive/folders/1q6-0Z9B0CPFutuTqzmeheEUSJM3tEL2o?usp=drive_link directory to all logs]):
** 2024: [https://docs.google.com/document/d/1QDWw5y4HpcE7CSpzXwftMqQT4FDgNJj-6fRrgWrqdug/edit?usp=sharing May (and before that)], [https://docs.google.com/document/d/1Rh2gYBV2E454xVYEv8jx5IXKd1N2Z05ns4dhI2XCE08/edit?usp=sharing June], [https://docs.google.com/document/d/1beUpp6rgwjqSxKbuHzXIR9hhPrGyi0j-SjtEIeav9Vg/edit?usp=sharing July], [https://docs.google.com/document/d/1pSzUXW5gd-4cZAR-gglTUVM_J2UHMa4wYJ2AzD4cdEo/edit?usp=sharing August], [https://docs.google.com/document/d/18pArAP0kRDhXHbty_y3TtrygmWkC2oLn-UD7njIpRIo/edit?usp=sharing September], [https://docs.google.com/document/d/1Qt6vhrqPAOG7W5Y_tLiod_QgNR1FDyzRxQcg6_oJQd4/edit?usp=sharing October], [https://docs.google.com/document/d/1pv9-Wne80FCrg0J5BkjOafmof_s3jlnc9HwyzWkIBfU/edit?usp=sharing November], [https://docs.google.com/document/d/1O5svOVwQZbUON1GMR_8nBR5LAL0M8RM2_zWW4oeBiLk/edit?usp=sharing December]
** 2025: [https://docs.google.com/document/d/1pUdSRyWgQa2py1PSLa3CKs_DDqL_SOgx6MMIp4cPnpk/edit?usp=sharing January],[https://docs.google.com/document/d/18cnIAaeM8UBiYPtsQn7g6TM8mjr57blSoY9l-6ShhwQ/edit?usp=sharing February], [https://docs.google.com/document/d/1k60i7nabWltnU38I7fGS2uq2-FUe5TMAKcM1BeLIRdY/edit?usp=sharing March], [https://docs.google.com/document/d/1CMaXBtA1ULNFbzuawYirP913A6dTa68cbYk2a7knirI/edit?usp=sharing April], [https://docs.google.com/document/d/13Kr8lYfFN9bzgFvCJi6nBUxbQHa3_eTgfjwaCUn3vCs/edit?tab=t.0 May], [https://docs.google.com/document/d/1ptGvQiB6SPgzJ-I6IgJ4bKK-3GPK-4LBpq7BG6sFPSg/edit?usp=sharing June], [https://docs.google.com/document/d/1XrOonOdwrkSDSWT2CwvzIaw7aRxBA4Sba1GCMRmkDZk/edit?usp=sharing July]
* SoD instructions:
** Daily routines: see [https://docs.google.com/document/d/1_iGnMRRrvb85Z0vT8-LzgQmCOKDSATEuQ0vTsn2C-dc/edit?usp=sharing SoD Routines] for detailed instructions.
** Instructions for [[making quick-look flare spectrograms and movies]]


==OVRO-LWA Solar-Dedicated Spectroscopic Imager==
==OVRO-LWA Solar-Dedicated Spectroscopic Imager==
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===Solar-Dedicated Modes===
===Solar-Dedicated Modes===
* Beamformer: the beamformer uses the 256 core antennas to form a synthesized beam of more than 1 degree in size that tracks the Sun from sunrise to sunset. This permits a continuous record of the full-Stokes total flux (without spatial resolution) of the Sun (a dynamic spectrum) with 24 kHz frequency resolution (3072 frequencies from 15-90 MHz) and as low as 1 ms time resolution.
* Beamformer: The OVRO-LWA beamformer uses the 256 antennas in the core region to form a synthesized beam of more than 1 degree in size that tracks the Sun from sunrise to sunset. This permits a continuous record of the full-Stokes total flux (without spatial resolution) of the Sun (a dynamic spectrum) with 24 kHz frequency resolution (3072 frequencies from 13.4-86.9 MHz) and as low as 1 ms time resolution.
 
* Slow Visibility Imaging: in this mode, the entire 352-element array is interferometrically correlated to provide visibilities for imaging at all 3072 frequencies at 10-s time resolution.  This is ideal for imaging quiet Sun and slowly-varying emission such as coronal mass ejections and active region variability.


* Fast Visibility Imaging: in this mode, a subset of 48 antennas (chosen to include mainly outer antennas to maintain good spatial resolution) is interferometrically correlated to provide visibilities for imaging at 768 frequencies (96 kHz frequency resolution) at 0.1-s time resolution.  This is ideal for imaging rapidly varying emission such as type II and type III bursts as well as many other solar spectral fine structures.
* Standard Interferometric Imaging (also known as "Slow Visibilities"): In this mode, the entire 352-element array is interferometrically correlated to provide visibilities for imaging at all 3072 frequencies at 10-s time resolution.  This is ideal for imaging quiet Sun and slowly-varying emission such as coronal mass ejections and active region variability.


===Inital Data Access===
* Bursty Interferometric Imaging (also known as "Fast Visibilities"): In this mode, a subset of 48 antennas (chosen to include mainly outer antennas to maintain good spatial resolution) is interferometrically correlated to provide visibilities for imaging at 768 frequencies (96 kHz frequency resolution) at 0.1-s time resolution. This is ideal for imaging rapidly varying emission such as type II and type III bursts as well as many other solar spectral fine structures.
In its current commissioning state, we try to run the beamformer and imaging pipeline every day in real-time since November 2023 (no latency for beamforming spectrograms and 5-10 min latency for images). Quicklook real-time spectrograms/images can be accessed from http://ovsa.njit.edu/status.php. To access data from previous days, use the following links (replace yyyymmdd with the date you desire):
* Quicklook beamformer total-power spectrograms: http://ovsa.njit.edu/lwa-data/1min_spectra/yyyymmdd/. Check this link for additional daily plots [[Daily OVRO-LWA Beamformer Data]].
* Quicklook multi-frequency movies at 1-min cadence: http://ovsa.njit.edu/lwa-data/1min_images/yyyymmdd/movie_yyyy-mm-dd.html


Note our pipeline processing development is still in the early phase. For example, absolute flux calibrations have not been done for the beamformer spectrograms. Also, artificial effects (including ionospheric refraction effects) are present in the images that cause distortions/shifts. We caution interested users only to consider them for quick-look purposes at this point. Please contact the EOVSA PIs (Dale Gary, Bin Chen) if you intend to use them for science.
===Data Access===
* OVRO-LWA solar data release v1.0 is available! Please refer to the [[OVRO-LWA Data Products]] page for more information.


===OVRO-LWA Operation Notes===
===OVRO-LWA Operation Notes===

Revision as of 20:24, 26 November 2025

Owens Valley Solar Arrays (OVSA) is a university-led radio facility dedicated to solar astrophysics and space weather research. Located in the Owens Valley Radio Observatory (OVRO) near Big Pine, California, the operations of OVSA include the Expanded Owens Valley Solar Array (EOVSA) observing in the microwave regime (1-18 GHz), as well as the solar and space weather aspects of the newly commissioned Long Wavelength Array at the Owens Valley Radio Observatory (OVRO-LWA), which observes in the meter-decameter wavelength regime (13-87 MHz). Please refer to our home page for more general descriptions of the facility. This wiki serves as the site for OVSA documentation.

Operation of OVSA is supported by the National Science Foundation under Grant AGS-2436999. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. NSF.jpg

Latest OVSA Science Highlights

OVSA Science Highlight No. 6: Detection of Radio Gyroresonance Emission from a CME

Cme 20240309.jpeg

This study reports the first possible detection of thermal gyroresonance emission from a CME. This breakthrough offers a new potential method for measuring the magnetic field of CMEs. [Contributed by Surajit Mondal (New Jersey Institute of Technology); Edited by B. Chen. Posted on September 26, 2025.]

OVSA Science Highlight No. 5: Is CME's Magnetic Flux Conserved?

Cme mfr.jpeg

According to this study, the answer is "probably yes." The conclusion is made by using ultrabroadband radio imaging spectroscopy to derive the magnetic field evolution of an erupting CME from the low to middle corona. [Contributed by Xingyao Chen (New Jersey Institute of Technology); Edited by B. Chen. Posted on September 19, 2025.]

OVSA Science Highlight No. 4: When the Sun Meets the Crab

Crab solar conjunction.jpeg

When the Crab Nebula passes behind the Sun each June, radio telescopes can catch its distorted signals, providing a rare way to probe turbulence in the Sun’s extended atmosphere out to more than 10 solar radii. [Contributed by Peijin Zhang (New Jersey Institute of Technology); Edited by B. Chen. Posted on September 11, 2025.]

OVSA Science Highlight No. 3: The First EOVSA "Cold" Solar Flare

Cold flare.jpeg

This study takes advantage of EOVSA's microwave imaging spectroscopy capability and multi-wavelength observations to measure the coronal magnetic field and track the flare energy partitioning. The results show ample magnetic free energy to drive efficient electron acceleration, with the energy deposition of nonthermal electrons alone accounting for the observed thermal response, reinforcing cold flares as clean cases of particle-driven heating. [Contributed by Gregory Fleishman (New Jersey Institute of Technology); Edited by B. Chen. Posted on August 20, 2025.]

OVSA Science Highlight No. 2: Two Phases of Impulsive SEP Acceleration

SEP illustration gemini.jpeg

M. Wang et al. analyze a solar energetic particle (SEP) event associated with an eruptive X-class flare and found two distinct impulsive SEP acceleration phases. They are suggested to link to different magnetic reconnection regimes during the eruption, which govern the timing and energy of particles released into interplanetary space. [Contributed by Meiqi Wang (New Jersey Institute of Technology); Edited by B. Chen. Posted on August 19, 2025.]

OVSA Science Highlight No. 1: Microwave Precursor of a Major Solar Eruption

Solar eruption nasa.jpeg

A study by Y. Kou et al. presents the first spatially resolved microwave imaging spectroscopy of the precursor phase of a major solar eruption. The findings reveal that thermal electron emissions dominate during the slow-rise phase, supporting a scenario of moderate magnetic reconnection prior to the flare’s impulsive onset. [Contributed by Yuankun Kou (Nanjing University); Edited by B. Chen. Posted on August 2, 2025.]

We welcome contributions at all times. Please refer to the OVSA Science Highlights page for author guidelines and a complete list of highlights.

OVSA Publications

Our collection of publications that utilize OVSA data is available at this NASA/ADS Library. If you have a paper that is missing from this library, please email Bin Chen (bin.chen [at] njit.edu).

EOVSA Flare List

OVSA Observing

OVSA Weekly Observing Reports

OVSA Scientist on Duty

EOVSA Observing Log

2016 November; December

2017 January; February; March; April; May; June; July; August; September; October; November; December

2018 January; February; March; April; May; June; July; August; September; October; November; December

2019 January; February; March; April; May; June; July; August; September; October; November; December

2020 January; February; March; April; May; June; July; August; September; October; November; December

2021 January; February; March; April; May; June; July; August; September; October; November; December

2022 SQL Outage

2023 January; February; March; April; May; June; July; August; September; October; November; December

2024 January; February; March; April; May; June; July; August; September; October; November; December

2025 January; February; March; April; May; June; July; August; September; October; November; December

Using OVSA Data

  • EOVSA Data Products: An introduction to standard EOVSA spectrogram and spectral image products with example scripts for reading and plotting.
  • OVRO-LWA Solar Data Products: An introduction to OVRO-LWA solar spectrogram and spectral image products with example scripts for reading and plotting.
  • OVSA Data Policy: Policy for using OVSA data products.
  • Analysis Software: These are for in-depth use of EOVSA data (from calibrated visibilities) and tools for quantitative analysis.
    • SunCASA A wrapper around CASA (the Common Astronomy Software Applications package) for synthesis imaging and visualizing solar spectral imaging data. CASA is one of the leading software tool for "supporting the data post-processing needs of the next generation of radio astronomical telescopes such as ALMA and VLA", an international effort led by the National Radio Astronomy Observatory. The current version of CASA uses Python (2.7) interface. More information about CASA can be found on NRAO's CASA website . Note, CASA is available ONLY on UNIX-BASED PLATFORMS (and therefore, so is SunCASA).
    • GSFIT A IDL-widget(GUI)-based spectral fitting package called gsfit, which provides a user-friendly display of EOVSA image cubes and an interface to fast fitting codes (via platform-dependent shared-object libraries).
    • pyGSFIT A Python-widget(pyQT)-based spectral fitting package, which provides a user-friendly display of EOVSA image cubes, spatially resolved spectra, and an interface to scipy-based fitting codes.
    • Spectrogram Software
    • Mapping Software
  • Data Analysis Guides (for those who start from raw data)

EOVSA Documentation


EOVSA System Software

OVRO-LWA Solar-Dedicated Spectroscopic Imager

The OVRO-LWA (Owens Valley Radio Observatory Long Wavelength Array) has recently been upgraded to include a solar-dedicated beam and two solar imaging modes (slow visibilities of 352 antennas with a 10-s cadence, and fast visibilities of 48 antennas with a 0.1-s cadence). The large collecting area and excellent calibration provide unprecedented high-sensitivity imaging of the quiet Sun and bursts. The array is currently in commissioning and observations are not yet continuous, but they are becoming more so. See the daily realtime data at http://ovsa.njit.edu/status.php for real-time display of the spectrogram and a selection of images, both updated on a 1-min cadence.

Solar-Dedicated Modes

  • Beamformer: The OVRO-LWA beamformer uses the 256 antennas in the core region to form a synthesized beam of more than 1 degree in size that tracks the Sun from sunrise to sunset. This permits a continuous record of the full-Stokes total flux (without spatial resolution) of the Sun (a dynamic spectrum) with 24 kHz frequency resolution (3072 frequencies from 13.4-86.9 MHz) and as low as 1 ms time resolution.
  • Standard Interferometric Imaging (also known as "Slow Visibilities"): In this mode, the entire 352-element array is interferometrically correlated to provide visibilities for imaging at all 3072 frequencies at 10-s time resolution. This is ideal for imaging quiet Sun and slowly-varying emission such as coronal mass ejections and active region variability.
  • Bursty Interferometric Imaging (also known as "Fast Visibilities"): In this mode, a subset of 48 antennas (chosen to include mainly outer antennas to maintain good spatial resolution) is interferometrically correlated to provide visibilities for imaging at 768 frequencies (96 kHz frequency resolution) at 0.1-s time resolution. This is ideal for imaging rapidly varying emission such as type II and type III bursts as well as many other solar spectral fine structures.

Data Access

  • OVRO-LWA solar data release v1.0 is available! Please refer to the OVRO-LWA Data Products page for more information.

OVRO-LWA Operation Notes

OVRO-LWA Operation Notes

Tohbans

Trouble Shooting Guide

Tohban Records

Owen's Notes

Caius' Notes

Tohban EOVSA Imaging Tutorial A-Z

Tohban OVRO-LWA Imaging Tutorial

Tohban Guide to Self Calibration and Imaging for EOVSA

Guide to Upgrade SolarSoft(SSW)

Star Pointing Notes

VLA Flare List and Publications

See this link for a list of flare observations made by the Karl G. Jansky Very Large Array (VLA). Below is a partial list of publications that utilize VLA solar data (see also this NASA/ADS Library).

Radio Data from Around The Heliosphere

Radio Astronomy Lecture Notes

Here is a link to the Radio Astronomy Lecture Notes adapted from the Phys728: Radio Astronomy graduate-level course Prof. Dale Gary taught at NJIT until Spring 2019.

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