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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

36151 results found.

  1. GRB 260225A: WINTER J-band upper limit
  2. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  3. GRB 260226A: COLIBRÍ optical upper limits
  4. GRB 260226A: LCOGT Optical Upper Limit
  5. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  6. GRB 260226A: Glowbug gamma-ray detection
  7. GRB 260226A: NuSTAR detection of bright prompt emission
  8. GRB 260226A : GROWTH-India Telescope optical observations
  9. GRB 260226A: LAST optical upper limit
  10. GRB 260226A: Fermi GBM observation
  11. GRB 260226A: Fermi-LAT refined analysis
  12. Fermi GRB 260226A: Global MASTER-Net observations report
  13. GRB 260226A: AstroSat CZTI detection of bright long burst
  14. GRB 260226A: Fermi-LAT detection of a bright burst
  15. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  16. GRB260225A: SVOM/ECLAIRs refined position
  17. GRB 260226A: Fermi GBM Final Real-time Localization
  18. GRB 260225A: EP-FXT follow-up observation
  19. GRB 260225A: SVOM/VT optical observation
  20. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  21. GRB 260225C: Fermi GBM Final Real-time Localization
  22. GRB 260223A: Fermi GBM Observation
  23. GRB 260225A: SVOM/VT optical upper limits
  24. GRB 260225B: Fermi GBM Final Real-time Localization
  25. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  26. GRB 260225A: SVOM detection of a burst
  27. GRB 260223A: Glowbug gamma-ray detection
  28. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  29. GRB 260223A: SVOM/VT optical observation
  30. GRB 260223A: SVOM/GRM observation
  31. GRB 260223A: COLIBRÍ further optical observations and a brightening
  32. GRB 260223A: COLIBRÍ optical observations
  33. GRB 260223A: DDOTI Optical Candidate
  34. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  35. Fermi GRB 260223A: Global MASTER-Net observations report
  36. GRB 260223A: Fermi GBM Final Real-time Localization
  37. GRB 260222A: Fermi GBM Final Real-time Localization
  38. Fermi GRB 260221B: Global MASTER-Net observations report
  39. GRB 260221B: Fermi GBM Final Real-time Localization
  40. Fermi GRB 260221A: Global MASTER-Net observations report
  41. GRB 260221A: Fermi GBM Final Real-time Localization
  42. GRB 260219A: AstroSat CZTI detection
  43. GRB 260219A: GECAM-B observation of a long burst
  44. Fermi GRB 260219A: Global MASTER-Net observations report
  45. GRB 260219A: Fermi GBM Final Real-time Localization
  46. GRB 260217A: Fermi GBM Final Localization
  47. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  48. EP260214b: Mondy optical observations
  49. EP260210a: Mondy optical upper limits
  50. Konus-Wind detection of GRB 260212A
  51. GRB 260208A: AbAO and Terskol optical upper limits
  52. GRB 260208A: continued Mondy optical observations
  53. IPN triangulation of GRB 260212A
  54. GRB 260213A: GECAM-B observation of a short burst
  55. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  56. GRB 260216A: Fermi GBM Final Real-time Localization
  57. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  58. EP260214a: Optical upper limits with Kinder observations
  59. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  60. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  61. GRB 260211A: SVOM/VT optical counterpart
  62. GRB 260212A: AstroSat CZTI detection
  63. GRB 260212A: Fermi GBM Observation
  64. GRB 260212A: GECAM-B observation
  65. EP260213a: Mondy R-band optical upper limit
  66. GRB 260212A: SVOM/GRM observation of a long burst
  67. GRB 260213B: Fermi GBM Final Localization
  68. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  69. GRB 260211A - SVOM/ECLAIRs refined analysis
  70. GRB 260204A: SVOM/ECLAIRs refined analysis
  71. GRB 260213A: Fermi GBM Final Localization
  72. GRB 260211A: EP-FXT follow-up observation
  73. GRB 260211A: SVOM/VT optical observation
  74. GRB 260212A: Glowbug gamma-ray detection
  75. GRB 260211A: GOTO optical upper limit
  76. Fermi GRB 260212A: Global MASTER-Net observations report
  77. GRB 260212A: Fermi GBM Final Real-time Localization
  78. GRB 260211A: LAST optical upper limit
  79. GRB 260210A: SVOM/GRM observation
  80. Fermi GBM Sub-Threshold Detection of GRB 260211A
  81. Konus-Wind detection of GRB 260207B
  82. GRB 260128B: SVOM/ECLAIRs refined analysis
  83. GRID detection of GRB 260207B
  84. GRB 260211A: LCO optical upper limits
  85. GRB260131A/B: 3.6m DOT Optical Observations
  86. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  87. GRB 260211A: SVOM detection of a burst
  88. Konus-Wind detection of GRB 260209B
  89. GRB 260208A: Swift UVOT detection
  90. Konus-Wind detection of GRB 260127B
  91. Fermi GRB 260210C: Global MASTER-Net observations report
  92. GRB 260208A: LCO detection of the optical counterpart
  93. IPN triangulation of GRB 260207B (short/hard with EE)
  94. GRB 260210C: Fermi GBM Final Real-time Localization
  95. GRB 260210A: Glowbug gamma-ray detection
  96. GRB 260210B: Fermi GBM Final Real-time Localization
  97. GRB 260210A: AstroSat CZTI detection
  98. GRB 260208C: AstroSat CZTI detection
  99. GRB 260208B: refined analysis of the EP-FXT observation
  100. GRB 260207B: AstroSat CZTI detection

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