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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

32509 results found.

  1. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  2. sb26021801: SVOM/C-GFT upper limit
  3. EP260223a: COLIBRÍ optical upper limits
  4. GRB 260223A: SVOM/VT optical observation
  5. GRB 260223A: SVOM/GRM observation
  6. GRB 260223A: COLIBRÍ further optical observations and a brightening
  7. EP260221a: Optical upper limit with Kinder observations
  8. GRB 260223A: COLIBRÍ optical observations
  9. GRB 260223A: DDOTI Optical Candidate
  10. Fermi GRB 260223A: Global MASTER-Net observations report
  11. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  12. EP260221a: COLIBRÍ optical counterpart candidate
  13. EP260221a: Gemini South z-band upper limit
  14. EP260221a: Global MASTER-Net observations report
  15. EP260221a: EP-FXT follow-up observation
  16. Fermi GRB 260221B: Global MASTER-Net observations report
  17. EP260221a: Xinglong optical upper limit
  18. Fermi GRB 260221A: Global MASTER-Net observations report
  19. EP260221a: GOTO optical upper limit
  20. EP260221a: COLIBRÍ optical upper limit
  21. SVOM alert sb26021801: LCO optical upper limit
  22. GRB 260219A: AstroSat CZTI detection
  23. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  24. GRB 260219A: GECAM-B observation of a long burst
  25. Fermi GRB 260219A: Global MASTER-Net observations report
  26. SVOM alert sb26021801: LAST optical upper limit
  27. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  28. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  29. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  30. EP260214b: Mondy optical observations
  31. EP260214b: 1.3m DFOT optical upper limit
  32. EP260210a: Mondy optical upper limits
  33. Konus-Wind detection of GRB 260212A
  34. GRB 260208A: AbAO and Terskol optical upper limits
  35. GRB 260208A: continued Mondy optical observations
  36. IPN triangulation of GRB 260212A
  37. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  38. GRB 260213A: GECAM-B observation of a short burst
  39. EP260214b: Liverpool Telescope optical observations
  40. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  41. EP260214b: Optical upper limit with Kinder observations
  42. EP260214a: Optical upper limits with Kinder observations
  43. EP260214b: EP-FXT follow-up observation
  44. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  45. EP260214b: DDOTI Optical Detection
  46. EP260214b: GROWTH-India Telescope optical upper limit
  47. EP260214a: VLT near-infrared observation
  48. EP260214b: SVOM/VT optical observation
  49. EP260214a: NOT optical upper limits
  50. EP260214a: COLIBRÍ optical upper limits
  51. EP260214b: OHP/T120 optical observations
  52. EP260214a: refined analysis of the EP-FXT observation
  53. EP260214b: LCO optical counterpart detection
  54. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  55. GRB 260211A: SVOM/VT optical counterpart
  56. EP260214b: COLIBRÍ optical observations
  57. EP260214a: SVOM/VT optical upper limits
  58. EP260214b: NOT optical counterpart detection
  59. EP260214a: Global MASTER-Net observations report
  60. GRB 260212A: AstroSat CZTI detection
  61. GRB 260212A: Fermi GBM Observation
  62. EP260213a: Liverpool Telescope optical upper limits
  63. EP260213a: Global MASTER-Net observations report
  64. EP260213a: COLIBRÍ optical upper limits
  65. GRB 260212A: GECAM-B observation
  66. EP260213a: Optical upper limits with Kinder observations
  67. EP260213a: SVOM/VT optical upper limit
  68. EP260213a: Mondy R-band optical upper limit
  69. EP260213a: NUTTelA-TAO Early Optical Limits
  70. EP260213a: SVOM/C-GFT upper limit
  71. EP260213a: refined analysis of the EP-FXT observation
  72. GRB 260212A: SVOM/GRM observation of a long burst
  73. GRB 260211A - SVOM/ECLAIRs refined analysis
  74. GRB 260204A: SVOM/ECLAIRs refined analysis
  75. GRB 260211A: EP-FXT follow-up observation
  76. GRB 260211A: SVOM/VT optical observation
  77. GRB 260212A: Glowbug gamma-ray detection
  78. GRB 260211A: GOTO optical upper limit
  79. Fermi GRB 260212A: Global MASTER-Net observations report
  80. GRB 260211A: LAST optical upper limit
  81. GRB 260210A: SVOM/GRM observation
  82. Fermi GBM Sub-Threshold Detection of GRB 260211A
  83. Konus-Wind detection of GRB 260207B
  84. GRB 260128B: SVOM/ECLAIRs refined analysis
  85. GRID detection of GRB 260207B
  86. GRB 260211A: LCO optical upper limits
  87. GRB260131A/B: 3.6m DOT Optical Observations
  88. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  89. GRB 260208A: Swift UVOT detection
  90. Konus-Wind detection of GRB 260127B
  91. EP260209a: COLIBRÍ optical upper limit
  92. Fermi GRB 260210C: Global MASTER-Net observations report
  93. EP260209a: LCO optical upper limits
  94. EP260210a: Global MASTER-Net observations report
  95. EP260210a: refined analysis of the EP-FXT observation
  96. EP260209a: Global MASTER-Net observations report
  97. GRB 260208A: LCO detection of the optical counterpart
  98. EP260210a: Optical upper limits with Kinder observations
  99. IPN triangulation of GRB 260207B (short/hard with EE)
  100. GRB 260210A: Glowbug gamma-ray detection

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