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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"

37770 results found.

  1. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  2. GRB 250703A: EIRSAT-1 GMOD Detection
  3. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  4. GRB 250704B: Swift/UVOT Upper Limits
  5. GRB 250704A: Swift/UVOT Detection
  6. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  7. GRB 250704B: Insight-HXMT detection
  8. Konus-Wind detection of GRB 250703A
  9. IPN triangulation of GRB 250703A
  10. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  11. EP250704a/GRB 250704B: FTW optical and NIR observations of the counterpart
  12. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  13. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  14. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  15. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  16. GRB 250702F: Kilonova-Catcher optical afterglow detection
  17. GRB 250702F: Monte Agliale Observatory optical observations
  18. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  19. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  20. EP250704a / GRB 250704B: JinShan optical observations
  21. GRB 250704A: SVOM/VT optical observation
  22. EP250704a / GRB 250704B: SAO RAS optical observations
  23. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  24. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  25. EP250704a / GRB 250704B: SVOM/VT optical blue counterpart
  26. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  27. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  28. GRB 250702A: Insight-HXMT detection
  29. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  30. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  31. EP250704a / GRB250704B: Swift-XRT counterpart detection
  32. GRB 250704A: Swift-XRT afterglow detection
  33. GRB 250702B / EP2050702a: FTW optical and NIR observations
  34. Konus-Wind detection of GRB 250702F
  35. EP250704a / GRB 250704B - REM observations
  36. GRB 250702F: GROWTH-India Telescope optical observations
  37. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  38. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  39. EP250702a: WFST optical observations
  40. EP250704a: Einstein Probe detection of an X-ray transient
  41. GRB 250704B: SVOM/GRM observation of a short burst
  42. GRB 250702F: optical photometry from Konkoly
  43. GRB 250704A: REM detection of the optical afterglow
  44. GRB 250702F: SVOM/VT optical observation
  45. GRB 250704A: SVOM detection of a burst
  46. GRB 250702F: Swift/UVOT Detection
  47. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  48. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  49. Fermi GRB 250703A: Global MASTER-Net observations report
  50. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  51. GRB 250702F: Swift-XRT refined Analysis
  52. GRB 250702F: Fermi GBM Observation
  53. GRB 250702F: Leavitt Observatory optical observations
  54. GRB 250702F: AKO Optical Afterglow Detection
  55. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  56. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  57. GRB 250702A: GECAM-B detection
  58. GRB 250702F: Skynet Optical Observations
  59. GRB 250424A: VIRT Optical Upper Limit
  60. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  61. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  62. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  63. GRB 250702F: TRT Optical Observation
  64. GRB 250703A: DDOTI Optical Upper Limit
  65. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  66. GRB 250702F: REM optical afterglow detection
  67. GRB 250702F: DDOTI Optical Observation
  68. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  69. GRB 250703A: Fermi GBM Final Real-time Localization
  70. EP250702a/GRB 250702B,C,D,E: GOTO optical upper limits
  71. GRB 250702F: COLIBRÍ Observations of the Afterglow
  72. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  73. Fermi GRB 250702E: Global MASTER-Net observations report
  74. Fermi GRB 250702B: Global MASTER-Net observations report
  75. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  76. GRB 250702F: Enhanced Swift-XRT position
  77. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  78. GRB 250702F: NOT observations of the optical afterglow
  79. GRB 250702F: MASTER optical afterglow observation
  80. Fermi GRB 250702F: Global MASTER-Net observations report
  81. Fermi GRB 250702C: Global MASTER-Net observations report
  82. GRB 250702F: GOTO optical counterpart detection
  83. GRB 250702F: Ondrejov D50 optical afterglow detection
  84. GRB 250702F: Swift detection of a burst with an optical counterpart
  85. Swift GRB 250702F: Global MASTER-Net observations report
  86. GRB 250702F: Fermi GBM Final Real-time Localization
  87. Fermi GBM Triggers 250702B, C, D and E are likely from the same source
  88. GRB 250702E: Fermi GBM Final Real-time Localization
  89. Konus-Wind detection of GRB 250627A
  90. IPN triangulation of GRB 250627A (short)
  91. GRB 250702A: Fermi GBM Detection
  92. GRB 250702D: Fermi GBM Final Localization Correction
  93. GRB 250702C: Fermi GBM Final Real-time Localization
  94. GRB 250702B: Fermi GBM Final Real-time Localization
  95. GRB 250702A: BALROG localization (Fermi Trigger 773142852 / GRB 250702413)
  96. GRB 250702A: Fermi GBM Final Real-time Localization
  97. Fermi Gamma-ray Burst Monitor trigger 772838080/250628885 is not a GRB
  98. GRB 250628B: Swift-XRT observations
  99. Fermi Gamma-ray Burst Monitor trigger 772981768/250630548 is not a GRB
  100. GRB 250628B: SVOM/VT optical upper limit

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