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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 200522A: Further HST F125W Observations
  2. Fermi GRB 200607B: Global MASTER-Net observations report
  3. GRB 200607B: Fermi GBM Final Real-time Localization
  4. Fermi GRB 200607A: Global MASTER-Net observations report
  5. IPN triangulation of GRB 200605A (short)
  6. GRB 200607A: Fermi GBM Final Localization
  7. GRB 200607A: BALROG localization (Fermi Trigger 613212114 / GRB 200607362)
  8. GRB 200530A: Fermi GBM detection
  9. GRB 200530A: CALET Gamma-Ray Burst Monitor detection
  10. Correction to the GCN 27886: Previous bursts of 1RXS J1708-4009 (Swift trigger 975998)
  11. 1RXS J1708−4009: Swift-BAT refined analysis
  12. Fermi GRB 200605A: Global MASTER-Net observations report
  13. GRB 200605A: Fermi GBM Final Real-time Localization
  14. GRB 200530A: Fermi-LAT detection
  15. GRB 200604A: AstroSat CZTI detection
  16. Fermi trigger No 612988790: Global MASTER-Net observations report
  17. Fermi GRB 200604A: Global MASTER-Net observations report
  18. GRB 200604A: Fermi GBM Final Real-time Localization
  19. Swift detection of an SGR-like burst from 1RXS J1708−4009
  20. Baksan Neutrino Observatory Alert 200603.12: Global MASTER-Net observations report
  21. GRB 200529A: Swift/UVOT Upper Limits
  22. Konus-Wind observation of GRB200528A
  23. GRB 200601A: Insight-HXMT/HE detection
  24. IceCube-200530A: Upper limits from a search for additional neutrino events in IceCube
  25. Baksan Neutrino Observatory Alert 200601.42: Global MASTER-Net observations report
  26. Fermi-LAT Gamma-ray Observations of IceCube-200530A
  27. GRB 200529A: MITSuME Akeno optical upper limits
  28. Fermi GRB 200601A: Global MASTER-Net observations report
  29. GRB 200601A: Fermi GBM Final Real-time Localization
  30. IceCube-200530A: not observable by Fermi-GBM
  31. Fermi GRB 200531A: Global MASTER-Net observations report
  32. IceCube-200530A: No significant detection in HAWC
  33. IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility
  34. IceCube-200530A: No ANTARES neutrino counterpart
  35. GRB 200531A: Fermi GBM Final Real-time Localization
  36. IceCube Alert 200530.33: Global MASTER-Net observations report
  37. GRB 200529A: Swift-BAT refined analysis
  38. Konus-Wind observation of GRB 200524A
  39. IceCube-200530A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  40. IceCube-200530A - IceCube observation of a high-energy neutrino candidate event
  41. GRB 200530A: AstroSat CZTI detection
  42. GRB 200529A: Swift-XRT refined Analysis
  43. Fermi GRB 200530A: Global MASTER-Net observations report
  44. GRB 200530A: Fermi GBM Final Real-time Localization
  45. GRB 200528A: CAHA Upper Limit
  46. GRB 200529A: Fermi GBM Detection
  47. GRB 200529A: LCO Optical Afterglow Detection
  48. Fermi GRB 200529B: Global MASTER-Net observations report
  49. Fermi trigger No 612429771: Global MASTER-Net observations report
  50. GRB 200528A: CALET Gamma-Ray Burst Monitor detection
  51. GRB 200529B: Fermi GBM Final Real-time Localization
  52. GRB 200529A: BOOTES-2/TELMA early optical upper limit
  53. GRB 200528A: Swift-XRT refined Analysis
  54. GRB 200524A: SAO RAS optical observations
  55. GRB 200524A: Assy continued optical observations
  56. GRB 200528A: Assy optical upper limit
  57. GRB 200529A: Enhanced Swift-XRT position
  58. GRB 200529A: KAIT Optical Afterglow Confirmation
  59. GRB 200529A: NOT optical afterglow
  60. GRB 200529A: Swift detection of a burst
  61. GRB 200529A: Fermi GBM Final Real-time Localization
  62. Swift GRB200529.04: Global MASTER-Net observations report
  63. GRB 200528A: NOT optical upper limits
  64. GRB 200528A: Fermi GBM Observation
  65. GRB 200528A: Swift/UVOT Upper Limits
  66. GRB 200528A: Swift-BAT refined analysis
  67. GRB 200528A: 1.3m DFOT Optical Upper Limits
  68. GRB 200528A: Nanshan/NEXT optical upper limit
  69. GRB 200528A: Enhanced Swift-XRT position
  70. Swift GRB 200528A: Global MASTER-Net observations report
  71. GRB 200528A: MITSuME Akeno optical upper limits
  72. GRB 200528A: Potential host galaxy in PanSTARRS, SDSS and WISE
  73. GRB 200528A: Swift detection of a burst
  74. GRB 200528A: Fermi GBM Final Real-time Localization
  75. GRB 200524A: Assy optical observations
  76. Baksan Neutrino Observatory Alert 200526.85: Global MASTER-Net observations report
  77. IceCube-200523A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 200522A: HST F125W new point source detection
  79. GRB 200522A: Hubble Space Telescope Near-IR F160W Observations
  80. GRB200524A: UVOT detection
  81. GRB 200524A: optical upper limits from further MITSuME Akeno observation
  82. Fermi GRB 200525A: Global MASTER-Net observations report
  83. GRB 200522A: Gemini North optical imaging
  84. GRB 200524A: CrAO optical observations
  85. GRB 200524A: Kitab observatory afterglow observations
  86. GRB 200525A: Fermi GBM Final Real-time Localization
  87. GRB 200524A: AstroSat CZTI detection
  88. GRB 200524A: Further Liverpool Telescope observations
  89. Fermi-LAT Gamma-ray Observations of IceCube-190523A
  90. GRB200521A: ASIM observation
  91. GRB 200524A: KAIT Optical Observations
  92. GRB 200524A: MITSuME Akeno optical observation
  93. GRB 171205A: ATCA observations of late-time radio emission
  94. GRB 200524A: Swift-XRT afterglow detection
  95. GRB 200524A: OAJ multicolor afterglow detection
  96. GRB 200524A: Fermi GBM detection
  97. GRB 200524: Swift/UVOT observations missed the ZTF20abbiixp position
  98. GRB 200524A: CAHA multicolor afterglow detection
  99. GRB 200524A: 1.3m DFOT Optical Observation of ZTF20abbiixp
  100. GRB 200524A: Liverpool Telescope observations

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