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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"

45705 results found.

  1. GRB 250625A: Enhanced Swift-XRT position
  2. Fermi GRB 250625A: Global MASTER-Net observations report
  3. GRB 250625A: Swift detection of a burst
  4. GRB 250625A: Fermi GBM Final Real-time Localization
  5. GRB 250617B: Mondy and SAO RAS optical observations on 2025-06-23, 2025-06-24
  6. GRB 250620A: AstroSat CZTI detection
  7. The EP-WXT trigger 01709179396 is likely a flaring star CSTAR 38580
  8. GRB 241018A: Maidanak optical observations
  9. GRB 250620C: AstroSat CZTI detection
  10. Fermi GRB 250624A: Global MASTER-Net observations report
  11. GRB 250624A: Fermi GBM Final Real-time Localization
  12. sb25061207/GRB 250612D - SVOM/ECLAIRs refined analysis
  13. Fermi GRB 250623A: Global MASTER-Net observations report
  14. GRB 250623A: Fermi GBM Final Real-time Localization
  15. GRB 250521A: VZLUSAT-2 detection
  16. GRB 250617B: Swift-BAT refined analysis
  17. Fermi trigger No 772190032: Global MASTER-Net observations report
  18. Konus-Wind detection of GRB 250620C
  19. IPN triangulation of GRB 250620C (long/bright)
  20. GRB 250621B: SVOM/GRM detection of a possible magnetar X-ray burst
  21. GRB 250620C: SVOM/GRM observation
  22. GRB 250620A: SVOM/GRM observation of a short burst
  23. GRB250620A: Fermi GBM Observation
  24. GRB 250617B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  25. Fermi GRB 250621A: Global MASTER-Net observations report
  26. GRB 250619B: Fermi GBM Observation
  27. GRB 250621A: Fermi GBM Final Real-time Localization
  28. GRB 250620B: Swift/BAT-GUANO localization skymap of a burst
  29. GRB250620C: Fermi GBM Observation
  30. GRB 250506A - SVOM/ECLAIRs Refined analysis
  31. The EP-WXT trigger 01709179071 is likely a flaring star
  32. GRB 250620A: Swift/BAT-GUANO subthreshold detection of a possibly short burst
  33. GRB 250619B: Swift/BAT-GUANO localization skymap of a burst
  34. GRB 250620C: Fermi GBM Final Real-time Localization
  35. Fermi trigger No 772128434: Global MASTER-Net observations report
  36. GRB 250620B: Fermi GBM Final Real-time Localization
  37. GRB 250620A: Fermi GBM Final Real-time Localization
  38. EP-WXT trigger 01709179036: a new outburst of GRS 1739-278
  39. GRB 250617B: Nickel telescope optical observations
  40. GRB 250619B: Fermi GBM Final Real-time Localization
  41. Fermi trigger No 772058337: Global MASTER-Net observations report
  42. Fermi Gamma-ray Burst Monitor trigger 772058337/250619860 is not a GRB
  43. GRB 250615A: Kilonova-Catcher optical upper limits
  44. GRB 250619A: Fermi GBM Final Real-time Localization
  45. GRB 250617B: Assy AZT-20 Optical Observations
  46. GRB 250612A / Swift J1643.6−3854: Swift-BAT refined analysis
  47. Fermi GRB 250617A: Global MASTER-Net observations report
  48. GRB 250615A/EP250615a: FTW optical and NIR observations
  49. sb25061218/SVOM: OHP/T120 and OHP/T193 optical imaging and spectroscopic observations
  50. GRB 250617B: Swift/UVOT Detection
  51. GRB 250617B: Kilonova-Catcher optical afterglow detection
  52. GRB 250617B: VLT/X-shooter spectroscopic redshift z = 1.396
  53. GRB 250617B: COLIBRÍ optical observations
  54. GRB 250617B: NOT NIR observations of the afterglow
  55. GRB 250617B: Swift-XRT refined Analysis
  56. GRB 250617B: SVOM/VT optical observation
  57. GRB 250617B: NUTTelA-TAO early time optical observations
  58. Fermi trigger No 771886893: Global MASTER-Net observations report
  59. Swift GRB 250617B: Global MASTER-Net observations report
  60. GRB 250617B: GOTO optical upper limit
  61. GRB 250617B: Enhanced Swift-XRT position
  62. GRB 250617B: Fermi GBM Observation
  63. GRB 250615A: Swift-BAT refined analysis
  64. The EP-WXT trigger 01709178990 is likely a flaring star
  65. GRB 250617B: Fermi GBM Final Localization
  66. GRB 250617B: Ondrejov D50 optical afterglow detection
  67. GRB 250617B: SAO RAS optical observations
  68. GRB 250617B: Swift detection of a burst with an optical counterpart
  69. GRB 250615A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  70. GRB 250617A: Fermi GBM Final Real-time Localization
  71. IPN triangulation of GRB 250612C (short/hard)
  72. EP#01709178975: Swift-XRT counterpart detection
  73. EP-WXT trigger 01709178975: GOTO optical upper limit
  74. The EP-WXT trigger 01709178975 is likely a flaring star
  75. Konus-Wind detection of GRB 250615A / EP250615a
  76. GRB 250615A / EP250615a: AstroSat CZTI detection
  77. Fermi Gamma-ray Burst Monitor trigger 771803204/250616907 is not a GRB
  78. SVOM sb25061207: AbAO AS-32 Optical Upper Limit
  79. GRB 250615A: COLIBRÍ optical upper limit
  80. GRB 250615A: DDOTI Optical Upper Limit
  81. GRB 250615A: Swift/UVOT Upper Limits
  82. Konus-Wind detection of GRB 250612C (short/hard with extended emission)
  83. GRB 250615A: Swift-XRT refined Analysis
  84. sb25061207/SVOM: T120 OHP optical upper limit
  85. EP250615a/GRB 250615A: EP-WXT detection of a fast X-ray transient
  86. Fermi trigger No 771752663: Global MASTER-Net observations report
  87. EP-WXT trigger 01709178875: confirmation of a stellar flare by BOOTES-6
  88. The EP-WXT trigger 01709178875 is likely a flaring star
  89. GRB 250615A: Enhanced Swift-XRT position
  90. Fermi Gamma-ray Burst Monitor trigger 771718064/250615922 is not a GRB
  91. GRB 250615A: Prompt enhanced Swift-XRT position
  92. GRB 250615A: Swift detection of a burst
  93. Swift GRB 250615A: Global MASTER-Net observations report
  94. Fermi trigger No 771718064: Global MASTER-Net observations report
  95. Fermi Gamma-ray Burst Monitor trigger 771704505/250615765 is not a GRB
  96. GRID detection of GRB 250612C
  97. sb25061207: Mephisto optical upper limits
  98. IceCube alert 141029_8144692 retraction
  99. Fermi Gamma-ray Burst Monitor trigger 771596290/250614513 is not a GRB
  100. GRB 250614A: Fermi GBM Final Real-time Localization

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