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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"

26533 results found.

  1. sb26021801: SVOM/VT optical upper limits
  2. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  3. sb26021801: SVOM/C-GFT upper limit
  4. EP260223a: COLIBRÍ optical upper limits
  5. EP260223a: Einstein Probe detection of an X-ray transient
  6. GRB 260223A: SVOM/VT optical observation
  7. GRB 260223A: SVOM/GRM observation
  8. GRB 260223A: COLIBRÍ further optical observations and a brightening
  9. EP260221a: Optical upper limit with Kinder observations
  10. GRB 260223A: COLIBRÍ optical observations
  11. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  12. EP260221a: COLIBRÍ optical counterpart candidate
  13. EP260221a: EP-FXT follow-up observation
  14. EP260221a: Xinglong optical upper limit
  15. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  16. EP260221a: GOTO optical upper limit
  17. EP260221a: COLIBRÍ optical upper limit
  18. SVOM alert sb26021801: LCO optical upper limit
  19. EP260221a: Einstein Probe detection of an X-ray transient
  20. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  21. GRB 260219A: AstroSat CZTI detection
  22. GRB 260219A: GECAM-B observation of a long burst
  23. SVOM alert sb26021801: LAST optical upper limit
  24. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  25. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  26. sb26021801: SVOM detection of a long faint X-ray transient
  27. EP260214b: 1.3m DFOT optical upper limit
  28. Konus-Wind detection of GRB 260212A
  29. IPN triangulation of GRB 260212A
  30. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  31. GRB 260213A: GECAM-B observation of a short burst
  32. EP260214b: Liverpool Telescope optical observations
  33. EP260214b: Optical upper limit with Kinder observations
  34. EP260214a: Optical upper limits with Kinder observations
  35. EP260214b: EP-FXT follow-up observation
  36. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  37. EP260214b: DDOTI Optical Detection
  38. EP260214b: GROWTH-India Telescope optical upper limit
  39. EP260214b: SVOM/VT optical observation
  40. EP260214a: COLIBRÍ optical upper limits
  41. EP260214b: OHP/T120 optical observations
  42. EP260214a: refined analysis of the EP-FXT observation
  43. EP260214b: LCO optical counterpart detection
  44. GRB 260211A: SVOM/VT optical counterpart
  45. EP260214b: COLIBRÍ optical observations
  46. EP260214a: SVOM/VT optical upper limits
  47. EP260214b: NOT optical counterpart detection
  48. EP260214b: Einstein Probe detection of a fast X-ray transient
  49. EP260214a: Einstein Probe detection of an X-ray transient
  50. GRB 260212A: AstroSat CZTI detection
  51. GRB 260212A: Fermi GBM Observation
  52. EP260213a: COLIBRÍ optical upper limits
  53. GRB 260212A: GECAM-B observation
  54. EP260213a: Optical upper limits with Kinder observations
  55. EP260213a: SVOM/VT optical upper limit
  56. EP260213a: NUTTelA-TAO Early Optical Limits
  57. EP260213a: SVOM/C-GFT upper limit
  58. EP260213a: refined analysis of the EP-FXT observation
  59. EP260213a: Einstein Probe detection of a fast X-ray transient
  60. GRB 260212A: SVOM/GRM observation of a long burst
  61. GRB 260211A - SVOM/ECLAIRs refined analysis
  62. GRB 260204A: SVOM/ECLAIRs refined analysis
  63. GRB 260211A: EP-FXT follow-up observation
  64. GRB 260211A: SVOM/VT optical observation
  65. GRB 260212A: Glowbug gamma-ray detection
  66. GRB 260211A: GOTO optical upper limit
  67. GRB 260211A: LAST optical upper limit
  68. GRB 260210A: SVOM/GRM observation
  69. Fermi GBM Sub-Threshold Detection of GRB 260211A
  70. Konus-Wind detection of GRB 260207B
  71. GRB 260128B: SVOM/ECLAIRs refined analysis
  72. GRID detection of GRB 260207B
  73. GRB 260211A: LCO optical upper limits
  74. GRB260131A/B: 3.6m DOT Optical Observations
  75. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  76. GRB 260211A: SVOM detection of a burst
  77. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  78. Konus-Wind detection of GRB 260209B
  79. GRB 260208A: Swift UVOT detection
  80. Konus-Wind detection of GRB 260127B
  81. EP260209a: COLIBRÍ optical upper limit
  82. EP260210a: refined analysis of the EP-FXT observation
  83. GRB 260208A: LCO detection of the optical counterpart
  84. EP260209a: Einstein Probe detection of a fast X-ray transient
  85. EP260210a: Optical upper limits with Kinder observations
  86. IPN triangulation of GRB 260207B (short/hard with EE)
  87. GRB 260210A: Glowbug gamma-ray detection
  88. EP260210a: SVOM/VT optical upper limit
  89. GRB 260210A: AstroSat CZTI detection
  90. GRB 260208C: AstroSat CZTI detection
  91. EP260210a: COLIBRÍ optical upper limit
  92. EP260210a: SVOM/C-GFT upper limit
  93. GRB 260208B: refined analysis of the EP-FXT observation
  94. EP260210a: Einstein Probe detection of an X-ray transient
  95. GRB 260207B: AstroSat CZTI detection
  96. GRB 260208C: SVOM/GRM observation
  97. GRB 260204A: Swift-XRT afterglow detection
  98. GRB 260208B: AstroSat CZTI detection of a bright long burst
  99. GRB260208A: Liverpool Telescope optical follow-up observations
  100. GRB 260208A: Glowbug gamma-ray detection

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