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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"

23618 results found.

  1. GRB 260228A: SVOM/ECLAIRs refined analysis
  2. GRB 260225A: SVOM/ECLAIRs refined analysis
  3. EP260302a: LCO observations
  4. EP260302a: BOOTES-7 optical counterpart detection at early times
  5. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  6. GRB 251130B: TERI Gamma-ray detection
  7. GRB 260208A: TERI Gamma-ray detection
  8. GRB 260228A: CAHA 2.2m telescope optical upper limit
  9. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  10. EP260227a: Mephisto optical detection
  11. GRB 260228A: SVOM/VT optical upper limits
  12. GRB 260228A: SVOM detection of a burst
  13. EP260227a: COLIBRÍ optical observations
  14. EP260227a: NOT optical observations
  15. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  16. Konus-Wind detection of GRB 260226A
  17. GRB 260225A: WINTER J-band upper limit
  18. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  19. GRB 260226A: COLIBRÍ optical upper limits
  20. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  21. GRB 260226A: Glowbug gamma-ray detection
  22. GRB 260226A : GROWTH-India Telescope optical observations
  23. GRB 260226A: LAST optical upper limit
  24. GRB 260226A: AstroSat CZTI detection of bright long burst
  25. EP260214a: VLA 6 GHz detection
  26. GRB260225A: SVOM/ECLAIRs refined position
  27. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  28. GRB 260223A: Fermi GBM Observation
  29. EP260126a: VLA 6 GHz detection
  30. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  31. EP 260225.148: COLIBRÍ Confirmation of flaring star
  32. EP260223a: Xinglong optical upper limit
  33. GRB 260223A: Glowbug gamma-ray detection
  34. EP260213a: Mephisto optical upper limits
  35. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  36. EP260223a: COLIBRÍ optical upper limits
  37. GRB 260223A: COLIBRÍ further optical observations and a brightening
  38. EP260221a: Optical upper limit with Kinder observations
  39. GRB 260223A: COLIBRÍ optical observations
  40. GRB 260223A: DDOTI Optical Candidate
  41. EP260221a: COLIBRÍ optical counterpart candidate
  42. EP260221a: EP-FXT follow-up observation
  43. EP-WXT01709258519: Xinglong optical upper limit
  44. EP260221a: Xinglong optical upper limit
  45. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  46. EP260221a: GOTO optical upper limit
  47. EP260221a: COLIBRÍ optical upper limit
  48. SVOM alert sb26021801: LCO optical upper limit
  49. EP260221a: Einstein Probe detection of an X-ray transient
  50. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  51. GRB 260219A: AstroSat CZTI detection
  52. SVOM alert sb26021801: LAST optical upper limit
  53. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  54. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  55. EP-WXT 01709258455: NOT optical upper limits
  56. Konus-Wind detection of GRB 260212A
  57. IPN triangulation of GRB 260212A
  58. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  59. EP260214b: Optical upper limit with Kinder observations
  60. EP260214a: Optical upper limits with Kinder observations
  61. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  62. EP260214b: DDOTI Optical Detection
  63. EP260214a: NOT optical upper limits
  64. EP260214a: COLIBRÍ optical upper limits
  65. EP260214b: OHP/T120 optical observations
  66. EP260214b: LCO optical counterpart detection
  67. EP260214b: COLIBRÍ optical observations
  68. EP260214b: NOT optical counterpart detection
  69. EP260214b: Einstein Probe detection of a fast X-ray transient
  70. GRB 260212A: AstroSat CZTI detection
  71. EP260213a: COLIBRÍ optical upper limits
  72. EP260213a: Optical upper limits with Kinder observations
  73. EP260213a: NUTTelA-TAO Early Optical Limits
  74. EP260213a: SVOM/C-GFT upper limit
  75. GRB 260212A: SVOM/GRM observation of a long burst
  76. GRB 260211A - SVOM/ECLAIRs refined analysis
  77. GRB 260204A: SVOM/ECLAIRs refined analysis
  78. GRB 260211A: EP-FXT follow-up observation
  79. GRB 260211A: SVOM/VT optical observation
  80. GRB 260212A: Glowbug gamma-ray detection
  81. GRB 260211A: GOTO optical upper limit
  82. GRB 260211A: LAST optical upper limit
  83. Konus-Wind detection of GRB 260207B
  84. GRB 260128B: SVOM/ECLAIRs refined analysis
  85. GRB 260211A: LCO optical upper limits
  86. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  87. Konus-Wind detection of GRB 260209B
  88. Konus-Wind detection of GRB 260127B
  89. EP260209a: COLIBRÍ optical upper limit
  90. GRB 260208A: LCO detection of the optical counterpart
  91. EP260210a: Optical upper limits with Kinder observations
  92. IPN triangulation of GRB 260207B (short/hard with EE)
  93. GRB 260210A: Glowbug gamma-ray detection
  94. GRB 260210A: AstroSat CZTI detection
  95. GRB 260208C: AstroSat CZTI detection
  96. EP260210a: COLIBRÍ optical upper limit
  97. GRB 260207B: AstroSat CZTI detection
  98. GRB 260204A: Swift-XRT afterglow detection
  99. GRB 260208B: AstroSat CZTI detection of a bright long burst
  100. GRB 260208A: Glowbug gamma-ray detection

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