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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"

32551 results found.

  1. EP260227a: COLIBRÍ optical observations
  2. EP260227a: NOT optical observations
  3. GRB 260225A: SVOM/VT optical continued observations and upper limit
  4. GRID detection of GRB 260223A
  5. EP260227a: Global MASTER-Net observations report
  6. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  7. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  8. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  9. Konus-Wind detection of GRB 260226A
  10. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  11. EP260214a: VLT/FORS2 optical observations
  12. GRB 260225A: WINTER J-band upper limit
  13. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  14. GRB 260226A: COLIBRÍ optical upper limits
  15. GRB 260226A: LCOGT Optical Upper Limit
  16. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  17. GRB 260226A: Glowbug gamma-ray detection
  18. GRB 260226A: NuSTAR detection of bright prompt emission
  19. GRB 260226A : GROWTH-India Telescope optical observations
  20. GRB 260226A: LAST optical upper limit
  21. GRB 260226A: Fermi GBM observation
  22. GRB 260226A: Fermi-LAT refined analysis
  23. Fermi GRB 260226A: Global MASTER-Net observations report
  24. GRB 260226A: AstroSat CZTI detection of bright long burst
  25. EP260214a: VLA 6 GHz detection
  26. GRB 260226A: Fermi-LAT detection of a bright burst
  27. EP260224a: LCO optical upper limits
  28. GRB260225A: SVOM/ECLAIRs refined position
  29. GRB 260225A: EP-FXT follow-up observation
  30. GRB 260225A: SVOM/VT optical observation
  31. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  32. GRB 260223A: Fermi GBM Observation
  33. GRB 260225A: SVOM/VT optical upper limits
  34. EP260126a: VLA 6 GHz detection
  35. EP260223a: Liverpool Telescope upper limits
  36. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  37. EP 260225.148: COLIBRÍ Confirmation of flaring star
  38. EP260223a: Xinglong optical upper limit
  39. GRB 260223A: Glowbug gamma-ray detection
  40. EP260213a: Mephisto optical upper limits
  41. EP260223a: EP-FXT follow-up observation
  42. sb26021801: SVOM/VT optical upper limits
  43. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  44. sb26021801: SVOM/C-GFT upper limit
  45. EP260223a: COLIBRÍ optical upper limits
  46. GRB 260223A: SVOM/VT optical observation
  47. GRB 260223A: SVOM/GRM observation
  48. GRB 260223A: COLIBRÍ further optical observations and a brightening
  49. EP260221a: Optical upper limit with Kinder observations
  50. GRB 260223A: COLIBRÍ optical observations
  51. GRB 260223A: DDOTI Optical Candidate
  52. Fermi GRB 260223A: Global MASTER-Net observations report
  53. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  54. EP260221a: COLIBRÍ optical counterpart candidate
  55. EP260221a: Gemini South z-band upper limit
  56. EP260221a: Global MASTER-Net observations report
  57. EP260221a: EP-FXT follow-up observation
  58. Fermi GRB 260221B: Global MASTER-Net observations report
  59. EP260221a: Xinglong optical upper limit
  60. Fermi GRB 260221A: Global MASTER-Net observations report
  61. EP260221a: GOTO optical upper limit
  62. EP260221a: COLIBRÍ optical upper limit
  63. SVOM alert sb26021801: LCO optical upper limit
  64. GRB 260219A: AstroSat CZTI detection
  65. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  66. GRB 260219A: GECAM-B observation of a long burst
  67. Fermi GRB 260219A: Global MASTER-Net observations report
  68. SVOM alert sb26021801: LAST optical upper limit
  69. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  70. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  71. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  72. EP260214b: Mondy optical observations
  73. EP260214b: 1.3m DFOT optical upper limit
  74. EP260210a: Mondy optical upper limits
  75. Konus-Wind detection of GRB 260212A
  76. GRB 260208A: AbAO and Terskol optical upper limits
  77. GRB 260208A: continued Mondy optical observations
  78. IPN triangulation of GRB 260212A
  79. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  80. GRB 260213A: GECAM-B observation of a short burst
  81. EP260214b: Liverpool Telescope optical observations
  82. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  83. EP260214b: Optical upper limit with Kinder observations
  84. EP260214a: Optical upper limits with Kinder observations
  85. EP260214b: EP-FXT follow-up observation
  86. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  87. EP260214b: DDOTI Optical Detection
  88. EP260214b: GROWTH-India Telescope optical upper limit
  89. EP260214a: VLT near-infrared observation
  90. EP260214b: SVOM/VT optical observation
  91. EP260214a: NOT optical upper limits
  92. EP260214a: COLIBRÍ optical upper limits
  93. EP260214b: OHP/T120 optical observations
  94. EP260214a: refined analysis of the EP-FXT observation
  95. EP260214b: LCO optical counterpart detection
  96. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  97. GRB 260211A: SVOM/VT optical counterpart
  98. EP260214b: COLIBRÍ optical observations
  99. EP260214a: SVOM/VT optical upper limits
  100. EP260214b: NOT optical counterpart detection

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