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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"

37954 results found.

  1. GRB 250706A: REM optical/NIR observations
  2. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  3. Swift GRB 250706A: Global MASTER-Net observations report
  4. GRB 250706A: JinShan optical upper limits
  5. GRB 250706A: SAO RAS optical observations
  6. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  7. GRB250706B: Swift-XRT counterpart detection
  8. GRB 250706B: iTelescope optical observations
  9. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  10. GRB 250706B: SVOM/VT optical observation
  11. GRB 250706B: TRT bright optical counterpart detection
  12. GRB 250706A: GROWTH-India Telescope optical upper limit
  13. GRB 250706B: SVOM detection of a long burst
  14. GRB 250706A: Swift detection of a burst
  15. GRB 250704B: Swift-XRT refined Analysis
  16. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  17. GRB 250703A: EIRSAT-1 GMOD Detection
  18. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  19. GRB 250704B: Swift/UVOT Upper Limits
  20. GRB 250704A: Swift/UVOT Detection
  21. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  22. GRB 250704B: Insight-HXMT detection
  23. Konus-Wind detection of GRB 250703A
  24. IPN triangulation of GRB 250703A
  25. EP250704a/GRB 250704B: GSP observations of the optical counterpart
  26. EP250704a/GRB 250704B: FTW optical and NIR observations of the counterpart
  27. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  28. Konus-Wind detection of short/hard GRB 250704B/ EP250704a
  29. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  30. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  31. GRB 250702F: Kilonova-Catcher optical afterglow detection
  32. GRB 250702F: Monte Agliale Observatory optical observations
  33. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  34. EP250704a / GRB 250704B: VLT/X-shooter spectroscopic redshift z = 0.661
  35. EP250704a / GRB 250704B: JinShan optical observations
  36. GRB 250704A: SVOM/VT optical observation
  37. EP250704a / GRB 250704B: SAO RAS optical observations
  38. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  39. GRBs 250702B,D,E / EP250702a: fast fading, extremely red counterpart
  40. EP250704a / GRB 250704B: SVOM/VT optical blue counterpart
  41. EP250704a / GRB 250704B: Pan-STARRS iz-band imaging and photometry
  42. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  43. LIGO/Virgo/KAGRA S250704ab: Upper limits from Fermi-GBM Observations
  44. GRB 250702A: Insight-HXMT detection
  45. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  46. GRBs 250702B/C/D/E / EP250702a: Swift/UVOT Upper Limits
  47. EP250704a / GRB250704B: Swift-XRT counterpart detection
  48. GRB 250704A: Swift-XRT afterglow detection
  49. GRB 250702B / EP2050702a: FTW optical and NIR observations
  50. Konus-Wind detection of GRB 250702F
  51. EP250704a / GRB 250704B - REM observations
  52. GRB 250702F: GROWTH-India Telescope optical observations
  53. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  54. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  55. EP250702a: WFST optical observations
  56. EP250704a: Einstein Probe detection of an X-ray transient
  57. GRB 250704B: SVOM/GRM observation of a short burst
  58. GRB 250702F: optical photometry from Konkoly
  59. GRB 250704A: REM detection of the optical afterglow
  60. GRB 250702F: SVOM/VT optical observation
  61. GRB 250704A: SVOM detection of a burst
  62. GRB 250702F: Swift/UVOT Detection
  63. GRB 250702A: CALET Gamma-Ray Burst Monitor detection
  64. Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
  65. Fermi GRB 250703A: Global MASTER-Net observations report
  66. GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
  67. GRB 250702F: Swift-XRT refined Analysis
  68. GRB 250702F: Fermi GBM Observation
  69. GRB 250702F: Leavitt Observatory optical observations
  70. GRB 250702F: AKO Optical Afterglow Detection
  71. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  72. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  73. GRB 250702A: GECAM-B detection
  74. GRB 250702F: Skynet Optical Observations
  75. GRB 250424A: VIRT Optical Upper Limit
  76. GRBs 250702B/C/D/E / EP250702a: Swift XRT localization
  77. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  78. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  79. GRB 250702F: TRT Optical Observation
  80. GRB 250703A: DDOTI Optical Upper Limit
  81. GRBs 250702B,C,D,E / EP250702a: Konus-Wind detection of a hard X-ray transient activity
  82. GRB 250702F: REM optical afterglow detection
  83. GRB 250702F: DDOTI Optical Observation
  84. GRB 250702B,C,D,E / EP 250702a: MAXI/GSC detection
  85. GRB 250703A: Fermi GBM Final Real-time Localization
  86. EP250702a/GRB 250702B,C,D,E: GOTO optical upper limits
  87. GRB 250702F: COLIBRÍ Observations of the Afterglow
  88. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  89. Fermi GRB 250702E: Global MASTER-Net observations report
  90. Fermi GRB 250702B: Global MASTER-Net observations report
  91. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  92. GRB 250702F: Enhanced Swift-XRT position
  93. GRB 250702F: GTC/OSIRIS+ spectroscopic redshift z = 1.520
  94. GRB 250702F: NOT observations of the optical afterglow
  95. GRB 250702F: MASTER optical afterglow observation
  96. Fermi GRB 250702F: Global MASTER-Net observations report
  97. Fermi GRB 250702C: Global MASTER-Net observations report
  98. GRB 250702F: GOTO optical counterpart detection
  99. GRB 250702F: Ondrejov D50 optical afterglow detection
  100. GRB 250702F: Swift detection of a burst with an optical counterpart

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