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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"

43858 results found.

  1. GRB 251009B: Insight-HXMT detection of a short burst
  2. GRB 251007A: Swift-BAT refined analysis
  3. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  4. GRB 251007A: SVOM/GRM observation
  5. GRB 251007A: Insight-HXMT detection
  6. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  7. GRB 251007B - SVOM/ECLAIRs refined analysis
  8. SVOM/sb25101004: SVOM detection of a stellar flare
  9. GRB 251009A: Fermi GBM Final Localization
  10. GRB 250916A: TERI Gamma-ray detection
  11. GRB 250919A: TERI gamma-ray detection
  12. EP251006a: Global MASTER-Net observations report
  13. GRB 251006A: Fermi GBM Observation
  14. GRB 251007A: 1.5m OSN and 2.2m CAHA optical follow-up
  15. GRB 251002A - SVOM/ECLAIRs refined analysis
  16. IceCube alert 141456_888784 retraction
  17. IceCube Alert 251008A: Global MASTER-Net observations report
  18. GRB 251003A: Fermi GBM Observation
  19. GRB 251006B: Fermi GBM Observation
  20. GRB 251007B: COLIBRÍ optical upper limit
  21. GRB 251007A: AstroSat CZTI detection
  22. GRB 251006B/EP251006a: EP-FXT afterglow detection
  23. GRB 250917B: iTelescope T-26 upper limit
  24. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  25. GRB 251007B: SVOM/VT optical candidate
  26. GRB 251007A: Swift-XRT refined Analysis
  27. GRB 251007A: Enhanced Swift-XRT position
  28. GRB 251007B: Swift-XRT refined Analysis
  29. GRB 251007B: Enhanced Swift-XRT position
  30. GRB 251007A: NOT optical observations
  31. GRB 251007A: AKO Optical Upper Limit
  32. GRB 251007A: CALET Gamma-Ray Burst Monitor detection
  33. GRB 251006B: Insight-HXMT detection
  34. GRB 251007A: SVOM/C-GFT optical observations
  35. GRB 251005C: PRIME J-band upper limit
  36. Swift GRB 251007B: Global MASTER-Net observations report
  37. GRB 251007A: Glowbug gamma-ray detection
  38. GRB 251007B: SVOM/C-GFT upper limit
  39. Swift GRB 251007A: Global MASTER-Net observations report
  40. GRB 251007B: SVOM detection of a faint burst
  41. GRB 251007B: Swift detection of a burst
  42. GRB 251007A: Swift detection of a burst with an optical counterpart
  43. GRB 250702B/EP250702a: JWST/NIRCam Observations
  44. GRB 251006A: Swift/BAT-GUANO subthreshold detection of a short burst
  45. GRB 251005B: Glowbug gamma-ray detection
  46. EP251003a: LCO and VST fading optical counterpart
  47. GRB 251006B/EP251006a: SVOM/VT optical candidate
  48. GRB 251006B/EP251006a: EP-FXT follow-up observation
  49. GRB 251006B: SVOM/GRM observation
  50. GRB 251006B: COLIBRÍ optical upper limit
  51. GRB 251006B/EP251006a: EP-WXT detection
  52. GRB 251005C: SVOM/VT optical fading
  53. GRB 251005C: SVOM/GRM observation of a likely short GRB
  54. LIGO/Virgo/KAGRA S251006dd: Identification of a GW compact binary merger candidate
  55. Fermi GRB 251006B: Global MASTER-Net observations report
  56. GRB 251006B: BALROG localization (Fermi Trigger 781473909 / GRB 251006837)
  57. GRB 251006B: Fermi GBM Final Real-time Localization
  58. GRB 251006A (short): Glowbug gamma-ray detection
  59. GRB 251005C: COLIBRÍ optical observations
  60. Fermi GRB 251006A: Global MASTER-Net observations report
  61. GRB 251005C: VLT/X-shooter Imaging
  62. GRB 251003A: LAST optical observations
  63. GRB 251002A: LAST optical observations
  64. GRB 251006A: Fermi GBM Final Real-time Localization
  65. GRB 251005C: SVOM/VT optical candidate
  66. GRB 251005C: AstroSat CZTI detection
  67. GRB 251005C: Swift/UVOT Upper Limits
  68. GRB 250902A: MSU cubesats detection
  69. GRB 251005C: Swift-XRT refined Analysis
  70. GRB 251005C: Fermi GBM Observation
  71. Swift GRB 251005A: Global MASTER-Net observations report
  72. GRB 251005C: Enhanced Swift-XRT position
  73. GRB 251005C: GOTO optical upper limits
  74. Fermi trigger No 781367244: Global MASTER-Net observations report
  75. GRB 251005C: Swift detection of a burst
  76. GRB 251005B: Fermi GBM Final Real-time Localization
  77. GRB 251005A: Fermi GBM Final Localization
  78. GRB 251002A: Mondy/AZT-33IK optical observations
  79. GRB 251002A: Insight-HXMT detection
  80. GRB 251002A: Insight-HXMT detection
  81. EP251003a: Einstein Probe detection of an X-ray transient
  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. LIGO/Virgo/KAGRA S251003at: Retraction of GW compact binary merger candidate
  97. GRB 251002A: GOTO detection of optical counterpart
  98. GRB 251001C: SVOM/GRM observation
  99. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  100. GRB 251003A: Enhanced Swift-XRT position

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