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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"

45460 results found.

  1. GRB 260307A: TERI Gamma-ray detection
  2. GRB 260225D: TERI Gamma-ray detection
  3. GRB 251118A: TERI Gamma-ray detection
  4. GRB 251113A: TERI Gamma-ray detection
  5. GRB 260428A: TERI Gamma-ray detection
  6. Konus-Wind detection of GRB 260519C
  7. GRB 260520B: Fermi GBM Final Localization
  8. GRB 260509A: SVOM/ECLAIRs refined analysis
  9. GRB 260520A: Fermi GBM Final Localization
  10. GRB 260519D: Fermi GBM Final Localization Correction
  11. GRB 260519C: NuSTAR detection of prompt emission
  12. Konus-Wind detection of GRB 260518A
  13. GRB 260519B: Fermi GBM Final Localization
  14. GRB 260519A: Fermi GBM Final Localization
  15. GRB 260518A: AstroSat CZTI detection of a long burst
  16. GRB 260516D: SVOM/ECLAIRs refined analysis
  17. GRB 260515A: SVOM/ECLAIRs refined analysis
  18. GRB 260421B: radio detection with the VLA
  19. GRID detection of GRB 260511A
  20. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  21. GRB 260509A: CrAO ZTSh optical upper limit
  22. GRB 260516D: EP-FXT follow-up observation
  23. GRB 260516D: GOTO optical counterpart detection
  24. GRB 260516D: LCO optical observations
  25. GRB 260515A: further Liverpool Telescope observations
  26. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  27. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  28. GRB 260516D: GROWTH-India Telescope optical detection
  29. GRB 260516D: SVOM/VT optical bright candidate
  30. GRB 260516D: FRAM-ORM optical limit
  31. GRB 260515A: CrAO ZTSh BVRI optical observations
  32. Fermi GRB 260516C: Global MASTER-Net observations report
  33. SVOM GRB260516D: Global MASTER-Net observations report
  34. GRB 260516D: SVOM possible detection of a burst
  35. GRB 260516C: Fermi GBM Final Real-time Localization
  36. Konus-Wind detection of GRB 260515A
  37. GRB 260515A: Liverpool Telescope optical detection
  38. GRB 260515A: LCO optical counterpart detection
  39. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  40. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  41. GRB 260515A: EP-FXT follow-up observation
  42. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  43. EP260514a: NOT optical counterpart confirmation
  44. EP260514a: TRT optical counterpart candidate
  45. EP260514a: SVOM/VT optical candidate
  46. Fermi GRB 260516B: Global MASTER-Net observations report
  47. GRB 260516B: Fermi GBM Final Real-time Localization
  48. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  49. GRB 260515A: SVOM/VT optical observations
  50. GRB 260515A: OHP/T193 optical observations
  51. EP260514a: COLIBRÍ optical upper limits
  52. GRB 260516A: Fermi GBM Final Real-time Localization
  53. GRID detection of GRB 260507A
  54. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  55. GRB 260515A: LCO optical observations
  56. SVOM GRB 260515A: Global MASTER-Net observations report
  57. GRB 260515A: NOT optical observations.
  58. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  59. GRB 260515A: SVOM/VT optical candidate from VHF data
  60. GRB 260515A: JinShan optical counterpart candidate
  61. GRB 260515A: SVOM detection of a burst
  62. GRB 260510C: Glowbug gamma-ray detection
  63. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  64. EP260514a: GROWTH-India Telescope optical upper limit
  65. GRB 260511B: NOT optical observations
  66. Konus-Wind detection of GRB 260512A
  67. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  68. GRB 260511B: GMG Optical Upper Limit
  69. EP260514a: Global MASTER-Net observations report
  70. EP260514a: Einstein Probe detection of a fast X-ray transient
  71. EP260512a: LCO optical upper limits
  72. IPN triangulation of GRB 260512A
  73. GRB 260511B: Mephisto multi-band optical followup
  74. Fermi GRB 260514A: Global MASTER-Net observations report
  75. GRB 260512A: AstroSat CZTI detection
  76. The EP-WXT trigger 01709262077 is likely a flaring star
  77. EP260512a: EP-FXT follow-up observation
  78. EP260507a: Xinglong Schmidt optical counterpart detection
  79. GRB 260514A: Fermi GBM Final Real-time Localization
  80. EP260512a: Global MASTER-Net observations report
  81. Fermi GRB 260513A: Global MASTER-Net observations report
  82. Fermi GRB 260512A: Global MASTER-Net observations report
  83. GRB 260511B: further SAO RAS optical observations
  84. GRB 260513A: Fermi GBM Final Real-time Localization
  85. GRB 260509A: SVOM/VT optical observations
  86. Konus-Wind detection of GRB 260511B
  87. The EP-WXT trigger 01709262036 is likely a flaring star
  88. EP260512a: COLIBRÍ optical upper limits
  89. EP260512a: Einstein Probe detection of an X-ray transient
  90. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  91. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  92. GRB 260512A: NuSTAR detection of prompt emission
  93. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  94. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  95. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  96. GRB 260512A: Fermi GBM Final Real-time Localization
  97. GRB 260511A: Glowbug gamma-ray detection
  98. Konus-Wind detection of GRB 260511A
  99. MASS-Cube (GRID 2.0) detection of GRB 260511A
  100. MASS-Cube (GRID 2.0) detection of GRB 260507A

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