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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"

36137 results found.

  1. GRB 251011A: Fermi GBM Final Real-time Localization
  2. Fermi Gamma-ray Burst Monitor trigger 781824269/251010892 is not a GRB
  3. GRB 251007B: Swift/UVOT Upper Limits
  4. GRB 251010A: Fermi GBM Final Real-time Localization
  5. GRB251007A: Swift/UVOT Detection
  6. GRB 251009A: GECAM-B detection of a short burst
  7. GRB 251009A: Insight-HXMT detection of a short burst
  8. GRB 251009B (short): Glowbug gamma-ray detection
  9. GRB 251009B: Insight-HXMT detection of a short burst
  10. GRB 251007A: Swift-BAT refined analysis
  11. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  12. GRB 251007A: SVOM/GRM observation
  13. GRB 251007A: Insight-HXMT detection
  14. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  15. GRB 251007B - SVOM/ECLAIRs refined analysis
  16. GRB 251009A: Fermi GBM Final Localization
  17. GRB 250916A: TERI Gamma-ray detection
  18. GRB 250919A: TERI gamma-ray detection
  19. GRB 251006A: Fermi GBM Observation
  20. GRB 251007A: 1.5m OSN and 2.2m CAHA optical follow-up
  21. GRB 251002A - SVOM/ECLAIRs refined analysis
  22. GRB 251003A: Fermi GBM Observation
  23. GRB 251006B: Fermi GBM Observation
  24. GRB 251007B: COLIBRÍ optical upper limit
  25. GRB 251007A: AstroSat CZTI detection
  26. GRB 251006B/EP251006a: EP-FXT afterglow detection
  27. GRB 250917B: iTelescope T-26 upper limit
  28. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  29. GRB 251007B: SVOM/VT optical candidate
  30. GRB 251007A: Swift-XRT refined Analysis
  31. GRB 251007A: Enhanced Swift-XRT position
  32. GRB 251007B: Swift-XRT refined Analysis
  33. GRB 251007B: Enhanced Swift-XRT position
  34. GRB 251007A: NOT optical observations
  35. GRB 251007A: AKO Optical Upper Limit
  36. GRB 251007A: CALET Gamma-Ray Burst Monitor detection
  37. GRB 251006B: Insight-HXMT detection
  38. GRB 251007A: SVOM/C-GFT optical observations
  39. GRB 251005C: PRIME J-band upper limit
  40. Swift GRB 251007B: Global MASTER-Net observations report
  41. GRB 251007A: Glowbug gamma-ray detection
  42. GRB 251007B: SVOM/C-GFT upper limit
  43. Swift GRB 251007A: Global MASTER-Net observations report
  44. GRB 251007B: SVOM detection of a faint burst
  45. GRB 251007B: Swift detection of a burst
  46. GRB 251007A: Swift detection of a burst with an optical counterpart
  47. GRB 250702B/EP250702a: JWST/NIRCam Observations
  48. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  49. GRB 251005B: Glowbug gamma-ray detection
  50. GRB 251006B/EP251006a: SVOM/VT optical candidate
  51. GRB 251006B/EP251006a: EP-FXT follow-up observation
  52. GRB 251006B: SVOM/GRM observation
  53. GRB 251006B: COLIBRÍ optical upper limit
  54. GRB 251006B/EP251006a: EP-WXT detection
  55. GRB 251005C: SVOM/VT optical fading
  56. GRB 251005C: SVOM/GRM observation of a likely short GRB
  57. Fermi GRB 251006B: Global MASTER-Net observations report
  58. GRB 251006B: BALROG localization (Fermi Trigger 781473909 / GRB 251006837)
  59. GRB 251006B: Fermi GBM Final Real-time Localization
  60. GRB 251006A (short): Glowbug gamma-ray detection
  61. GRB 251005C: COLIBRÍ optical observations
  62. Fermi GRB 251006A: Global MASTER-Net observations report
  63. GRB 251005C: VLT/X-shooter Imaging
  64. GRB 251003A: LAST optical observations
  65. GRB 251002A: LAST optical observations
  66. GRB 251006A: Fermi GBM Final Real-time Localization
  67. GRB 251005C: SVOM/VT optical candidate
  68. GRB 251005C: AstroSat CZTI detection
  69. GRB 251005C: Swift/UVOT Upper Limits
  70. GRB 250902A: MSU cubesats detection
  71. GRB 251005C: Swift-XRT refined Analysis
  72. GRB 251005C: Fermi GBM Observation
  73. Swift GRB 251005A: Global MASTER-Net observations report
  74. GRB 251005C: Enhanced Swift-XRT position
  75. GRB 251005C: GOTO optical upper limits
  76. GRB 251005C: Swift detection of a burst
  77. GRB 251005B: Fermi GBM Final Real-time Localization
  78. GRB 251005A: Fermi GBM Final Localization
  79. GRB 251002A: Mondy/AZT-33IK optical observations
  80. GRB 251002A: Insight-HXMT detection
  81. GRB 251002A: Insight-HXMT detection
  82. GRB 251003A: J-band detection with WINTER
  83. GRB 251002A: NIR observations with WINTER
  84. Fermi GBM Sub-Threshold Detection of GRB 250910A
  85. GRB 251003A: Swift-BAT refined analysis
  86. GRB 251001B: NIR observations with WINTER
  87. GRB 251002A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  88. GRB 251003A: Swift/UVOT Upper Limits
  89. GRB 251002A: Swift/UVOT detection
  90. GRB 251001A: AstroSat CZTI detection
  91. GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
  92. GRB 251003A: Swift-XRT refined Analysis
  93. GRB 251003A: COLIBRÍ photometric redshift
  94. GRB 251003A: GOTO detection of the optical counterpart
  95. GRB 251002A: Fermi GBM Observation
  96. GRB 251002A: GOTO detection of optical counterpart
  97. GRB 251001C: SVOM/GRM observation
  98. GRB 251003A: Enhanced Swift-XRT position
  99. GRB 251002A: AKO Early Optical Afterglow Detection
  100. GRB 251003A: GTC/OSIRIS+ spectroscopic redshift z = 4.412

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