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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"

11511 results found.

  1. EP250215A: J band upper limit by SYSU 80cm telescope
  2. GRB 250225A: Fermi GBM Final Real-time Localization
  3. GRB 250207a: ATCA Radio Upper Limits
  4. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
  5. GRB 250119B: VZLUSAT-2 detection
  6. GRB 250223C: Fermi GBM Final Real-time Localization
  7. GRB 250202B: VZLUSAT-2 detection
  8. GRB 250210A: VZLUSAT-2 detection
  9. GRB 250206A: VZLUSAT-2 detection
  10. GRB 250223B: Fermi GBM Final Localization
  11. Fermi GRB 250223A: Global MASTER-Net observations report
  12. Fermi trigger No 762020305: Global MASTER-Net observations report
  13. GRB 250223A: Fermi GBM Final Real-time Localization
  14. Fermi trigger No 761805304: Global MASTER-Net observations report
  15. Fermi Gamma-ray Burst Monitor trigger 761867337/250221909 is not a GRB
  16. Fermi Gamma-ray Burst Monitor trigger 761788229/250220993 is not a GRB
  17. GRB 250220B: Fermi GBM Final Real-time Localization
  18. Fermi Gamma-ray Burst Monitor trigger 761782146/250220923 is not a GRB
  19. GRB 250220A: Fermi GBM Final Real-time Localization
  20. Konus-Wind detection of GRB 250217C (short)
  21. Konus-Wind detection of GRB 250215A / EP250215a
  22. GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
  23. GRB 250217C: DDOTI Upper Limits on the Optical Afterglow
  24. GRB 250217C: SVOM/GRM observation
  25. GRB 250217C: Fermi GBM Observation
  26. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  27. IPN triangulation of GRB 250217C (short)
  28. GRB 250216A: AstroSat CZTI detection
  29. GRB 250217C: AstroSat CZTI detection of a short burst
  30. Fermi GRB 250217C: Global MASTER-Net observations report
  31. GRB 250217C: Fermi GBM Final Real-time Localization
  32. Fermi GRB 250217A: Global MASTER-Net observations report
  33. GRANDMA/OPD observations of GRB250215A
  34. GRB 250217B: Fermi GBM Final Real-time Localization
  35. GRB 250217A: Fermi GBM Final Real-time Localization
  36. Fermi GRB 250216A: Global MASTER-Net observations report
  37. GRB 250215A / EP250215a: LCO detection of the afterglow
  38. GRB 250216A: Fermi GBM Final Real-time Localization
  39. GRB 250215A: Swift/UVOT Upper Limits
  40. GRB 250215A: COLIBRÍ/DDRAGO Optical Upper Limits on the Afterglow
  41. EP250215a / GRB 250215A : GTC redshift z = 4.61
  42. GRB 250215A: Fermi GBM Observation
  43. EP250215a / GRB 250215A : NOT optical observations
  44. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  45. GRB 250215A / EP250215a: Gemini-South optical observation of a likely rebrightening
  46. GRB 250215A: Swift-XRT refined Analysis
  47. GRB 250215A: SVOM/GRM observation
  48. EP250215a / GRB 250215A: AstroSat CZTI detection
  49. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  50. EP250215A/GRB 250215A: INTEGRAL SPI-ACS detection
  51. EP250215a / GRB 250215A (potentially): NOT likely optical counterpart
  52. Fermi GRB 250215A: Global MASTER-Net observations report
  53. GRB 250215A: Fermi GBM Final Real-time Localization
  54. Fermi trigger No 761206993: Global MASTER-Net observations report
  55. Fermi Gamma-ray Burst Monitor trigger 761206993/250214266 is not a GRB
  56. Fermi GRB 250214A: Global MASTER-Net observations report
  57. GRB 250214A: Fermi GBM Final Real-time Localization
  58. GRB 250210A: GRBAlpha detection
  59. Fermi GRB 250212A: Global MASTER-Net observations report
  60. Fermi trigger No 760945500: Global MASTER-Net observations report
  61. GRB 250212A: Fermi GBM Final Real-time Localization
  62. GRB 250207A: Fermi GBM Observation
  63. GRB 250206A: Fermi GBM Observation
  64. GRB 250205A / EP250205A: radio detection with the VLA
  65. Konus-Wind detection of GRB 250207A
  66. Konus-Wind detection of GRB 250206A
  67. GRB 250210A: SVOM/GRM observation of a long burst
  68. Fermi Gamma-ray Burst Monitor trigger 760945500/250211240 is not a GRB
  69. GRB 250207A: Skynet optical afterglow observations
  70. EP250207A: Upper limits from Fermi-GBM Observations
  71. GRB 250210A: INTEGRAL SPI-ACS detection
  72. GRB 250210A: AstroSat CZTI detection
  73. Fermi GRB 250210A: Global MASTER-Net observations report
  74. GRB 250210A: Fermi GBM Final Real-time Localization
  75. GRB 250204B: GRBAlpha detection
  76. GRB 250204A: GRBAlpha detection
  77. Fermi-LAT Gamma-ray Observations of IceCube-250207A
  78. GRB 250206A: Swift-XRT observations
  79. GRB 250206A: Tiled Swift observations
  80. GRB 250206A: EIRSAT-1 GMOD Detection
  81. GRB 250206A: Fermi-LAT detection
  82. GRB 250208A: Fermi GBM Final Real-time Localization
  83. GRB 250207A: REM IR afterglow detection
  84. GRB 250207A: FRAM-Auger optical detection
  85. Konus-Wind detection of GRB 250204B
  86. IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
  87. GRB 250207A: REM optical afterglow detection
  88. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  89. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  90. GRB 250207A: Fermi GBM Final Real-time Localization
  91. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  92. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  93. GRB 250206A: Fermi GBM Final Real-time Localization
  94. GRB 250205A: Fermi GBM Observation
  95. GRB 250204B: SVOM/GRM observation of a likely short burst
  96. Konus-Wind detection of GRB 250201A
  97. IPN triangulation of GRB 250201A
  98. Konus-Wind detection of GRB 250202B
  99. EP 250108A: Upper limits from Fermi-GBM Observations
  100. IPN triangulation of GRB 250204B (short/hard)

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