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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"

38207 results found.

  1. GRB 251014A: DDOTI Upper Limit
  2. GRB 251013C NUTTelA-TAO / BSTI Early Measurements
  3. GRB 251013C: ULL-ASTRO-MASTER detection of the optical afterglow with the LCO 40-cm telescope at Sutherland Observatory
  4. GRB 251013C: Asiago optical observations
  5. GRB 251013A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 251013C: ABObservatory optical observations
  7. GRB 251014A: SAO RAS optical upper limit
  8. GRB 251014A: Fermi GBM Observation
  9. GRB 251013C: J band observations by SYSU 80cm infrared telescope
  10. GRB 251013C: EP-FXT counterpart detection
  11. GRB 251013C: AstroSat CZTI detection
  12. GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
  13. GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
  14. GRB 251013C: ALMA detection
  15. GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
  16. GRB 251013C: DDOTI detection of the optical afterglow
  17. GRB 251013C: SLKT optical afterglow photometry
  18. Swift GRB 251014A: Global MASTER-Net observations report
  19. GRB 251014A: Swift detection of a possibly-short burst
  20. GRB 251014A: Fermi GBM Final Real-time Localization
  21. Fermi trigger No 782044789: Global MASTER-Net observations report
  22. Fermi GRB 251013C: Global MASTER-Net observations report
  23. Fermi GRB 251013B: Global MASTER-Net observations report
  24. Fermi GRB 251013D: Global MASTER-Net observations report
  25. GRB 251013C: Swift-XRT counterpart detection
  26. GRB 251013C: GOTO optical afterglow detection
  27. GRB 251013C: SAO RAS optical observations
  28. GRB 251013C: LCO optical afterglow detection
  29. GRB 251013C: Optical Observations via Virtual Telescope Project, Italy
  30. GRB 251013C: NOT spectroscopic redshift z = 0.572
  31. GRB 251013C: LAST detection of optical counterpart
  32. GRB 251013C: BOOTES-6 early optical detection
  33. GRB 251013D: Fermi GBM Final Real-time Localization
  34. GRB 251013C: SVOM/VT optical observation
  35. GRB 251013C: SVOM detection of a burst
  36. GRB 251013C: Fermi GBM Final Real-time Localization
  37. GRB 251013B: SVOM/GRM observation
  38. GRB 251013A: SVOM/GRM observation
  39. GRB 251003A: Mondy optical upper limit
  40. GRB 251013B: Fermi GBM Final Real-time Localization
  41. Fermi GRB 251013A: Global MASTER-Net observations report
  42. GRB 251013A: Fermi GBM Final Real-time Localization
  43. GRB 251011B inspection: MASTER orphan GRB detection
  44. GRB 251011A: Insight-HXMT detection
  45. GRB 251011B: Swift/UVOT Upper Limits
  46. Fermi GRB 251011A: Global MASTER-Net observations report
  47. GRB 251012A: Fermi GBM Final Real-time Localization
  48. GRB 251011B: SVOM/GRM observation
  49. GRB 251011B: Swift-XRT refined Analysis
  50. GRB 251011B: Fermi GBM Observation
  51. GRB 251011B : MASTER optical observations
  52. GRB 251011C: Fermi GBM Final Real-time Localization
  53. GRB 251011B: Enhanced Swift-XRT position
  54. GRB 251010A: AstroSat CZTI detection
  55. GRB 251011A: AstroSat CZTI detection
  56. GRB 251009B: SVOM/GRM observation of short GRB
  57. GRB 251011B: Swift detection of a burst
  58. GRB 251011B: Fermi GBM Final Real-time Localization
  59. GRB 251011A: Fermi GBM Final Real-time Localization
  60. Fermi Gamma-ray Burst Monitor trigger 781824269/251010892 is not a GRB
  61. GRB 251007B: Swift/UVOT Upper Limits
  62. GRB 251010A: Fermi GBM Final Real-time Localization
  63. GRB251007A: Swift/UVOT Detection
  64. GRB 251009A: GECAM-B detection of a short burst
  65. GRB 251009A: Insight-HXMT detection of a short burst
  66. GRB 251009B (short): Glowbug gamma-ray detection
  67. GRB 251009B: Insight-HXMT detection of a short burst
  68. GRB 251007A: Swift-BAT refined analysis
  69. GRB 251009A: SVOM/GRM observation of short GRB with possible tail emission
  70. GRB 251007A: SVOM/GRM observation
  71. GRB 251007A: Insight-HXMT detection
  72. GRB 251006A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 251007B - SVOM/ECLAIRs refined analysis
  74. GRB 251009A: Fermi GBM Final Localization
  75. GRB 250916A: TERI Gamma-ray detection
  76. GRB 250919A: TERI gamma-ray detection
  77. EP251006a: Global MASTER-Net observations report
  78. GRB 251006A: Fermi GBM Observation
  79. GRB 251007A: 1.5m OSN and 2.2m CAHA optical follow-up
  80. GRB 251002A - SVOM/ECLAIRs refined analysis
  81. IceCube Alert 251008A: Global MASTER-Net observations report
  82. GRB 251003A: Fermi GBM Observation
  83. GRB 251006B: Fermi GBM Observation
  84. GRB 251007B: COLIBRÍ optical upper limit
  85. GRB 251007A: AstroSat CZTI detection
  86. GRB 251006B/EP251006a: EP-FXT afterglow detection
  87. GRB 250917B: iTelescope T-26 upper limit
  88. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  89. GRB 251007B: SVOM/VT optical candidate
  90. GRB 251007A: Swift-XRT refined Analysis
  91. GRB 251007A: Enhanced Swift-XRT position
  92. GRB 251007B: Swift-XRT refined Analysis
  93. GRB 251007B: Enhanced Swift-XRT position
  94. GRB 251007A: NOT optical observations
  95. GRB 251007A: AKO Optical Upper Limit
  96. GRB 251007A: CALET Gamma-Ray Burst Monitor detection
  97. GRB 251006B: Insight-HXMT detection
  98. GRB 251007A: SVOM/C-GFT optical observations
  99. GRB 251005C: PRIME J-band upper limit
  100. Swift GRB 251007B: Global MASTER-Net observations report

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