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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"

37557 results found.

  1. Fermi GRB 260523A: Global MASTER-Net observations report
  2. GRB 260523B: Fermi GBM Final Real-time Localization
  3. GRB 260523A: Fermi GBM Final Real-time Localization
  4. GRB 260522A: Fermi GBM Observation
  5. GRB 260522B: NuSTAR detection of prompt emission
  6. GRB 260522B: Fermi GBM Final Real-time Localization
  7. GRB 260522A: GOTO optical upper limit
  8. Fermi trigger No 801135305: Global MASTER-Net observations report
  9. Fermi GRB 260522A: Global MASTER-Net observations report
  10. GRB 260522A: Fermi-LAT detection
  11. GRB 260519C: SVOM/GRM observation
  12. GRB 260522A: Fermi GBM Final Real-time Localization
  13. GRB 260511A: iTelescope T-75 optical detection
  14. GRB 260520B: SVOM/GRM observation
  15. GRB 260411B: TERI Gamma-ray detection
  16. GRB 260407A: TERI Gamma-ray detection
  17. GRB 260307A: TERI Gamma-ray detection
  18. GRB 260225D: TERI Gamma-ray detection
  19. GRB 251118A: TERI Gamma-ray detection
  20. GRB 251113A: TERI Gamma-ray detection
  21. GRB 260428A: TERI Gamma-ray detection
  22. Konus-Wind detection of GRB 260519C
  23. GRB 260520B: Fermi GBM Final Localization
  24. GRB 260509A: SVOM/ECLAIRs refined analysis
  25. GRB 260520A: Fermi GBM Final Localization
  26. GRB 260519D: Fermi GBM Final Localization Correction
  27. GRB 260519C: NuSTAR detection of prompt emission
  28. Konus-Wind detection of GRB 260518A
  29. GRB 260519B: Fermi GBM Final Localization
  30. GRB 260519A: Fermi GBM Final Localization
  31. GRB 260518A: AstroSat CZTI detection of a long burst
  32. GRB 260516D: SVOM/ECLAIRs refined analysis
  33. GRB 260515A: SVOM/ECLAIRs refined analysis
  34. GRB 260421B: radio detection with the VLA
  35. GRID detection of GRB 260511A
  36. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  37. GRB 260509A: CrAO ZTSh optical upper limit
  38. GRB 260516D: EP-FXT follow-up observation
  39. GRB 260516D: GOTO optical counterpart detection
  40. GRB 260516D: LCO optical observations
  41. GRB 260515A: further Liverpool Telescope observations
  42. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  43. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  44. GRB 260516D: GROWTH-India Telescope optical detection
  45. GRB 260516D: SVOM/VT optical bright candidate
  46. GRB 260516D: FRAM-ORM optical limit
  47. GRB 260515A: CrAO ZTSh BVRI optical observations
  48. Fermi GRB 260516C: Global MASTER-Net observations report
  49. GRB 260516D: SVOM possible detection of a burst
  50. GRB 260516C: Fermi GBM Final Real-time Localization
  51. Konus-Wind detection of GRB 260515A
  52. GRB 260515A: Liverpool Telescope optical detection
  53. GRB 260515A: LCO optical counterpart detection
  54. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  55. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  56. GRB 260515A: EP-FXT follow-up observation
  57. Fermi GRB 260516B: Global MASTER-Net observations report
  58. GRB 260516B: Fermi GBM Final Real-time Localization
  59. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  60. GRB 260515A: SVOM/VT optical observations
  61. GRB 260515A: OHP/T193 optical observations
  62. GRB 260516A: Fermi GBM Final Real-time Localization
  63. GRID detection of GRB 260507A
  64. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  65. GRB 260515A: LCO optical observations
  66. SVOM GRB 260515A: Global MASTER-Net observations report
  67. GRB 260515A: NOT optical observations.
  68. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  69. GRB 260515A: SVOM/VT optical candidate from VHF data
  70. GRB 260515A: JinShan optical counterpart candidate
  71. GRB 260515A: SVOM detection of a burst
  72. GRB 260510C: Glowbug gamma-ray detection
  73. GRB 260511B: NOT optical observations
  74. Konus-Wind detection of GRB 260512A
  75. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  76. GRB 260511B: GMG Optical Upper Limit
  77. IPN triangulation of GRB 260512A
  78. GRB 260511B: Mephisto multi-band optical followup
  79. Fermi GRB 260514A: Global MASTER-Net observations report
  80. GRB 260512A: AstroSat CZTI detection
  81. GRB 260514A: Fermi GBM Final Real-time Localization
  82. Fermi GRB 260513A: Global MASTER-Net observations report
  83. Fermi GRB 260512A: Global MASTER-Net observations report
  84. GRB 260511B: further SAO RAS optical observations
  85. GRB 260513A: Fermi GBM Final Real-time Localization
  86. GRB 260509A: SVOM/VT optical observations
  87. Konus-Wind detection of GRB 260511B
  88. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  89. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  90. GRB 260512A: NuSTAR detection of prompt emission
  91. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  92. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  93. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  94. GRB 260512A: Fermi GBM Final Real-time Localization
  95. GRB 260511A: Glowbug gamma-ray detection
  96. Konus-Wind detection of GRB 260511A
  97. MASS-Cube (GRID 2.0) detection of GRB 260511A
  98. MASS-Cube (GRID 2.0) detection of GRB 260507A
  99. GRB 260511B: SAO RAS optical observations
  100. GRB 260510D: Glowbug gamma-ray detection of a likely short burst

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