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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"

28246 results found.

  1. GRB 260226A : GROWTH-India Telescope optical observations
  2. GRB 260226A: LAST optical upper limit
  3. GRB 260226A: Fermi GBM observation
  4. LAT GRB260226.44: Global MASTER-Net observations report
  5. Fermi GRB 260226A: Global MASTER-Net observations report
  6. GRB 260226A: AstroSat CZTI detection of bright long burst
  7. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  8. EP260224a: LCO optical upper limits
  9. GRB 260225A: EP-FXT follow-up observation
  10. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  11. GRB 260223A: Fermi GBM Observation
  12. GRB 260225A: SVOM/VT optical upper limits
  13. EP260223a: Liverpool Telescope upper limits
  14. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  15. EP260224a: Einstein Probe detection of an X-ray transient
  16. EP 260225.148: COLIBRÍ Confirmation of flaring star
  17. EP260223a: Xinglong optical upper limit
  18. GRB 260223A: Glowbug gamma-ray detection
  19. EP260213a: Mephisto optical upper limits
  20. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  21. sb26021801: SVOM/C-GFT upper limit
  22. EP260223a: COLIBRÍ optical upper limits
  23. EP260223a: Einstein Probe detection of an X-ray transient
  24. GRB 260223A: SVOM/GRM observation
  25. GRB 260223A: COLIBRÍ further optical observations and a brightening
  26. EP260221a: Optical upper limit with Kinder observations
  27. GRB 260223A: COLIBRÍ optical observations
  28. GRB 260223A: DDOTI Optical Candidate
  29. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  30. Fermi GRB 260223A: Global MASTER-Net observations report
  31. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  32. EP260221a: COLIBRÍ optical counterpart candidate
  33. EP260221a: Gemini South z-band upper limit
  34. EP260221a: Global MASTER-Net observations report
  35. EP260221a: EP-FXT follow-up observation
  36. Fermi GRB 260221B: Global MASTER-Net observations report
  37. EP-WXT01709258519: Xinglong optical upper limit
  38. EP260221a: Xinglong optical upper limit
  39. Fermi GRB 260221A: Global MASTER-Net observations report
  40. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  41. EP260221a: GOTO optical upper limit
  42. EP260221a: COLIBRÍ optical upper limit
  43. SVOM alert sb26021801: LCO optical upper limit
  44. EP260221a: Einstein Probe detection of an X-ray transient
  45. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  46. Fermi GRB 260219A: Global MASTER-Net observations report
  47. SVOM alert sb26021801: LAST optical upper limit
  48. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  49. IceCube Alert 260217A: Global MASTER-Net observations report
  50. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  51. sb26021801: SVOM detection of a long faint X-ray transient
  52. EP-WXT 01709258455: NOT optical upper limits
  53. EP260214b: Mondy optical observations
  54. EP260214b: 1.3m DFOT optical upper limit
  55. EP260210a: Mondy optical upper limits
  56. GRB 260208A: AbAO and Terskol optical upper limits
  57. GRB 260208A: continued Mondy optical observations
  58. IPN triangulation of GRB 260212A
  59. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  60. EP260214b: Liverpool Telescope optical observations
  61. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  62. EP260214b: Optical upper limit with Kinder observations
  63. EP260214a: Optical upper limits with Kinder observations
  64. EP260214b: EP-FXT follow-up observation
  65. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  66. EP260214b: DDOTI Optical Detection
  67. EP260214b: GROWTH-India Telescope optical upper limit
  68. EP260214a: VLT near-infrared observation
  69. EP260214a: NOT optical upper limits
  70. EP260214a: COLIBRÍ optical upper limits
  71. EP260214b: OHP/T120 optical observations
  72. EP260214a: refined analysis of the EP-FXT observation
  73. EP260214b: LCO optical counterpart detection
  74. GRB 260211A: SVOM/VT optical counterpart
  75. EP260214b: COLIBRÍ optical observations
  76. EP260214b: NOT optical counterpart detection
  77. EP260214b: Einstein Probe detection of a fast X-ray transient
  78. EP260214a: Global MASTER-Net observations report
  79. EP260214a: Einstein Probe detection of an X-ray transient
  80. GRB 260212A: AstroSat CZTI detection
  81. GRB 260212A: Fermi GBM Observation
  82. EP260213a: Liverpool Telescope optical upper limits
  83. EP260213a: Global MASTER-Net observations report
  84. EP260213a: COLIBRÍ optical upper limits
  85. EP260213a: Optical upper limits with Kinder observations
  86. EP260213a: Mondy R-band optical upper limit
  87. EP260213a: SVOM/C-GFT upper limit
  88. EP260213a: refined analysis of the EP-FXT observation
  89. EP260213a: Einstein Probe detection of a fast X-ray transient
  90. EP/WXT 01709258378: NOT optical upper limits
  91. GRB 260212A: SVOM/GRM observation of a long burst
  92. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  93. GRB 260211A: EP-FXT follow-up observation
  94. GRB 260211A: SVOM/VT optical observation
  95. GRB 260212A: Glowbug gamma-ray detection
  96. Fermi GRB 260212A: Global MASTER-Net observations report
  97. GRB 260211A: LAST optical upper limit
  98. GRB 260210A: SVOM/GRM observation
  99. Fermi GBM Sub-Threshold Detection of GRB 260211A
  100. GRID detection of GRB 260207B

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