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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"

37956 results found.

  1. GRB 260520B: SVOM/GRM observation
  2. GRB 260411B: TERI Gamma-ray detection
  3. GRB 260407A: TERI Gamma-ray detection
  4. GRB 260307A: TERI Gamma-ray detection
  5. GRB 260225D: TERI Gamma-ray detection
  6. GRB 251118A: TERI Gamma-ray detection
  7. GRB 251113A: TERI Gamma-ray detection
  8. GRB 260428A: TERI Gamma-ray detection
  9. Konus-Wind detection of GRB 260519C
  10. GRB 260520B: Fermi GBM Final Localization
  11. GRB 260509A: SVOM/ECLAIRs refined analysis
  12. GRB 260520A: Fermi GBM Final Localization
  13. GRB 260519D: Fermi GBM Final Localization Correction
  14. GRB 260519C: NuSTAR detection of prompt emission
  15. Konus-Wind detection of GRB 260518A
  16. GRB 260519B: Fermi GBM Final Localization
  17. GRB 260519A: Fermi GBM Final Localization
  18. GRB 260518A: AstroSat CZTI detection of a long burst
  19. GRB 260516D: SVOM/ECLAIRs refined analysis
  20. GRB 260515A: SVOM/ECLAIRs refined analysis
  21. GRB 260421B: radio detection with the VLA
  22. GRID detection of GRB 260511A
  23. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  24. GRB 260509A: CrAO ZTSh optical upper limit
  25. GRB 260516D: EP-FXT follow-up observation
  26. GRB 260516D: GOTO optical counterpart detection
  27. GRB 260516D: LCO optical observations
  28. GRB 260515A: further Liverpool Telescope observations
  29. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  30. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  31. GRB 260516D: GROWTH-India Telescope optical detection
  32. GRB 260516D: SVOM/VT optical bright candidate
  33. GRB 260516D: FRAM-ORM optical limit
  34. GRB 260515A: CrAO ZTSh BVRI optical observations
  35. Fermi GRB 260516C: Global MASTER-Net observations report
  36. SVOM GRB260516D: Global MASTER-Net observations report
  37. GRB 260516D: SVOM possible detection of a burst
  38. GRB 260516C: Fermi GBM Final Real-time Localization
  39. Konus-Wind detection of GRB 260515A
  40. GRB 260515A: Liverpool Telescope optical detection
  41. GRB 260515A: LCO optical counterpart detection
  42. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  43. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  44. GRB 260515A: EP-FXT follow-up observation
  45. Fermi GRB 260516B: Global MASTER-Net observations report
  46. GRB 260516B: Fermi GBM Final Real-time Localization
  47. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  48. GRB 260515A: SVOM/VT optical observations
  49. GRB 260515A: OHP/T193 optical observations
  50. GRB 260516A: Fermi GBM Final Real-time Localization
  51. GRID detection of GRB 260507A
  52. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  53. GRB 260515A: LCO optical observations
  54. SVOM GRB 260515A: Global MASTER-Net observations report
  55. GRB 260515A: NOT optical observations.
  56. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  57. GRB 260515A: SVOM/VT optical candidate from VHF data
  58. GRB 260515A: JinShan optical counterpart candidate
  59. GRB 260515A: SVOM detection of a burst
  60. GRB 260510C: Glowbug gamma-ray detection
  61. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  62. GRB 260511B: NOT optical observations
  63. Konus-Wind detection of GRB 260512A
  64. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  65. GRB 260511B: GMG Optical Upper Limit
  66. EP260514a: Global MASTER-Net observations report
  67. IPN triangulation of GRB 260512A
  68. GRB 260511B: Mephisto multi-band optical followup
  69. Fermi GRB 260514A: Global MASTER-Net observations report
  70. GRB 260512A: AstroSat CZTI detection
  71. GRB 260514A: Fermi GBM Final Real-time Localization
  72. EP260512a: Global MASTER-Net observations report
  73. Fermi GRB 260513A: Global MASTER-Net observations report
  74. Fermi GRB 260512A: Global MASTER-Net observations report
  75. GRB 260511B: further SAO RAS optical observations
  76. GRB 260513A: Fermi GBM Final Real-time Localization
  77. GRB 260509A: SVOM/VT optical observations
  78. Konus-Wind detection of GRB 260511B
  79. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  80. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  81. GRB 260512A: NuSTAR detection of prompt emission
  82. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  83. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  84. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  85. GRB 260512A: Fermi GBM Final Real-time Localization
  86. GRB 260511A: Glowbug gamma-ray detection
  87. Konus-Wind detection of GRB 260511A
  88. MASS-Cube (GRID 2.0) detection of GRB 260511A
  89. MASS-Cube (GRID 2.0) detection of GRB 260507A
  90. GRB 260511B: SAO RAS optical observations
  91. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  92. GRB 260511B: FRAM-ORM optical detection
  93. GRB 260511A: EP-FXT follow-up observation
  94. GRB 260511B: EP-FXT follow-up observation
  95. GRB 260511B: LCO optical counterpart detection
  96. GRB260511B: MAO/AZT-22 optical observations
  97. GRB 260511A: SVOM/VT optical observations
  98. GRB 260511B: LCO optical observations
  99. GRB 260511B: OHP/T193 spectroscopic observations
  100. GRB 260511B: GOTO optical counterpart detection

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