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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"

39271 results found.

  1. EP260227a: Global MASTER-Net observations report
  2. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  3. Konus-Wind detection of GRB 260226A
  4. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  5. GRB 260225A: WINTER J-band upper limit
  6. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  7. GRB 260226A: COLIBRÍ optical upper limits
  8. GRB 260226A: LCOGT Optical Upper Limit
  9. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  10. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  11. GRB 260226A: Glowbug gamma-ray detection
  12. GRB 260226A: NuSTAR detection of bright prompt emission
  13. GRB 260226A : GROWTH-India Telescope optical observations
  14. GRB 260226A: LAST optical upper limit
  15. GRB 260226A: Fermi GBM observation
  16. GRB 260226A: Fermi-LAT refined analysis
  17. LAT GRB260226.44: Global MASTER-Net observations report
  18. Fermi GRB 260226A: Global MASTER-Net observations report
  19. GRB 260226A: AstroSat CZTI detection of bright long burst
  20. GRB 260226A: Fermi-LAT detection of a bright burst
  21. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  22. EP260224a: LCO optical upper limits
  23. GRB260225A: SVOM/ECLAIRs refined position
  24. GRB 260226A: Fermi GBM Final Real-time Localization
  25. GRB 260225A: EP-FXT follow-up observation
  26. GRB 260225A: SVOM/VT optical observation
  27. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  28. GRB 260225C: Fermi GBM Final Real-time Localization
  29. GRB 260223A: Fermi GBM Observation
  30. GRB 260225A: SVOM/VT optical upper limits
  31. GRB 260225B: Fermi GBM Final Real-time Localization
  32. EP260126a: VLA 6 GHz detection
  33. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  34. GRB 260225A: SVOM detection of a burst
  35. EP 260225.148: COLIBRÍ Confirmation of flaring star
  36. GRB 260223A: Glowbug gamma-ray detection
  37. EP260213a: Mephisto optical upper limits
  38. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  39. sb26021801: SVOM/C-GFT upper limit
  40. EP260223a: COLIBRÍ optical upper limits
  41. GRB 260223A: SVOM/VT optical observation
  42. GRB 260223A: SVOM/GRM observation
  43. GRB 260223A: COLIBRÍ further optical observations and a brightening
  44. GRB 260223A: COLIBRÍ optical observations
  45. GRB 260223A: DDOTI Optical Candidate
  46. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  47. Fermi GRB 260223A: Global MASTER-Net observations report
  48. GRB 260223A: Fermi GBM Final Real-time Localization
  49. EP260221a: COLIBRÍ optical counterpart candidate
  50. GRB 260222A: Fermi GBM Final Real-time Localization
  51. EP260221a: Global MASTER-Net observations report
  52. Fermi GRB 260221B: Global MASTER-Net observations report
  53. GRB 260221B: Fermi GBM Final Real-time Localization
  54. Fermi GRB 260221A: Global MASTER-Net observations report
  55. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  56. GRB 260221A: Fermi GBM Final Real-time Localization
  57. EP260221a: COLIBRÍ optical upper limit
  58. GRB 260219A: AstroSat CZTI detection
  59. GRB 260219A: GECAM-B observation of a long burst
  60. Fermi GRB 260219A: Global MASTER-Net observations report
  61. GRB 260219A: Fermi GBM Final Real-time Localization
  62. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  63. IceCube Alert 260217A: Global MASTER-Net observations report
  64. GRB 260217A: Fermi GBM Final Localization
  65. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  66. sb26021801: SVOM detection of a long faint X-ray transient
  67. EP260214b: Mondy optical observations
  68. EP260214b: 1.3m DFOT optical upper limit
  69. EP260210a: Mondy optical upper limits
  70. Konus-Wind detection of GRB 260212A
  71. GRB 260208A: AbAO and Terskol optical upper limits
  72. GRB 260208A: continued Mondy optical observations
  73. IPN triangulation of GRB 260212A
  74. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  75. GRB 260213A: GECAM-B observation of a short burst
  76. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  77. GRB 260216A: Fermi GBM Final Real-time Localization
  78. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  79. EP260214a: Optical upper limits with Kinder observations
  80. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  81. EP260214b: GROWTH-India Telescope optical upper limit
  82. EP260214a: COLIBRÍ optical upper limits
  83. EP260214b: LCO optical counterpart detection
  84. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  85. GRB 260211A: SVOM/VT optical counterpart
  86. EP260214b: COLIBRÍ optical observations
  87. EP260214a: Global MASTER-Net observations report
  88. GRB 260212A: AstroSat CZTI detection
  89. GRB 260212A: Fermi GBM Observation
  90. EP260213a: Global MASTER-Net observations report
  91. EP260213a: COLIBRÍ optical upper limits
  92. GRB 260212A: GECAM-B observation
  93. EP260213a: Mondy R-band optical upper limit
  94. EP260213a: SVOM/C-GFT upper limit
  95. GRB 260212A: SVOM/GRM observation of a long burst
  96. GRB 260213B: Fermi GBM Final Localization
  97. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  98. GRB 260211A - SVOM/ECLAIRs refined analysis
  99. GRB 260204A: SVOM/ECLAIRs refined analysis
  100. GRB 260213A: Fermi GBM Final Localization

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