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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"

12390 results found.

  1. Integral GRB250114.55: Global MASTER-Net observations report
  2. GRB 250114B : GIT optical upper limit
  3. EP250111a: SAO RAS optical upper limit
  4. Swift GRB250114A: Global MASTER-Net OT detection
  5. Swift GRB 250114A: Global MASTER-Net observations report
  6. EP241021a: SMA radio observation
  7. EP250109b: optical upper limits with the Liverpool Telescope
  8. Fermi trigger No 758442826: Global MASTER-Net observations report
  9. GRB 250109A / EP250109a: Mephisto optical upper limits
  10. EP250108a: Mephisto detection
  11. EP250111a: Global MASTER-Net observations report
  12. EP250108a / AT 2025kg: Swift UVOT detections
  13. EP250108a: EP-FXT follow-up observation
  14. GRB 250109a: GMG Optical Upper Limit
  15. EP250109a: Swift/UVOT non-detection
  16. GRB 250108B: 1.3m DFOT upper limit
  17. GRB 250108B: REM optical/NIR upper limits
  18. EP250109a: SVOM/VT optical candidate
  19. EP250109a: Global MASTER-Net observations report
  20. EP250109a: GOTO optical upper limits
  21. EP250109a: Swift/XRT non-detection
  22. GRB 250108A: Swift/UVOT Upper Limits
  23. EP250108a: Global MASTER-Net observations report
  24. GRB 250108A: NOT optical upper limit
  25. Swift GRB 250108B: Global MASTER-Net observations report
  26. GRB 250103A: 1.6m Mephisto optical observations
  27. GRB 250108A: Swift-XRT afterglow detection
  28. GRB 250108B: Swift/UVOT Upper Limits
  29. GRB 250108B: Swift detection of a burst
  30. Fermi GRB 250107B: Global MASTER-Net observations report
  31. GRB 250101A: J band upper limit by SYSU 80cm telescope
  32. GRB 250103B: REM optical/NIR upper limits
  33. GRB 250106A: Swift-XRT observations
  34. Fermi trigger No 757753930: Global MASTER-Net observations report
  35. GRB 250103A: Bassano Bresciano Observatory upper limit
  36. GRB 250103A: Swift-XRT observations
  37. GRB 241229A: 1.3m DFOT upper limit
  38. GRB 241228A: 1.3m DFOT upper limit
  39. GRB 250103A: TSHAO optical upper limit
  40. GRB 250103B: LCOGT Optical Upper Limit
  41. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  42. Swift GRB 250103B: Global MASTER-Net observations report
  43. EP250101a: Liverpool Telescope optical upper limit
  44. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  45. Fermi GRB 250102A: Global MASTER-Net observations report
  46. GRB 250103A: GOTO optical upper limit
  47. GRB 250103A: SVOM/C-GFT optical upper limit
  48. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  49. IceCube Alert 250102.58: Global MASTER-Net observations report
  50. EP241231b: optical upper limit with the Liverpool Telescope
  51. EP250101a: Xinglong optical upper limit
  52. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  53. GRB 250101A: Swift/UVOT Detection
  54. Fermi GRB 250101B: Global MASTER-Net observations report
  55. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  56. Swift GRB250101.56: Global MASTER-Net observations report
  57. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  58. EP241217A: J band upper limit by SYSU 80cm telescope
  59. GRB 241229B: SAO RAS optical upper limit
  60. IceCube-Cascade 241228A: Upper limits from a search for additional neutrino events in IceCube
  61. GRB 241229B: SVOM/VT optical candidate
  62. GRB 241229A: Swift-XRT observations
  63. Konus-Wind detection of GRB 241228A
  64. EP240702a: 7DT Optical upper limits
  65. GRB 240606B: 7DT Optical upper limits
  66. Fermi trigger No 757231333: Global MASTER-Net observations report
  67. GRB241229B: UVOT upper limits
  68. GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
  69. Swift GRB 241229B: Global MASTER-Net observations report
  70. GRB 241229A: GOTO optical upper limits
  71. GRB 241228A: NOT optical upper limits
  72. Fermi GRB 241228B: Global MASTER-Net observations report
  73. Swift GRB 241228A: Global MASTER-Net observations report
  74. GRB 241228A: GROWTH-India telescope optical upper limit
  75. GRB 241228A: Swift/UVOT Upper Limits
  76. GRB 241228A: Swift detection of a burst
  77. IceCube-241224A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 241217A/EP241217b: continued SOAR observations
  79. Fermi GRB 241226A: Global MASTER-Net observations report
  80. EP241223a: Mondy AZT-33IK optical observations
  81. GRB 241223A: Swift-XRT observations
  82. Fermi trigger No 756678579: Global MASTER-Net observations report
  83. IceCube Alert 241224.30: Global MASTER-Net observations report
  84. EP241223a: Global MASTER-Net observations report
  85. EP241113a: Non-detection in Radio Follow-up Observations with eMERLIN
  86. GRB241113A: 7DT Optical upper limits
  87. Fermi GRB 241223A: Global MASTER-Net observations report
  88. GRB 241217A / EP241217b: Non-detection in ATCA Radio Follow-up Observations
  89. Fermi trigger No 756447119: Global MASTER-Net observations report
  90. Fermi GRB 241221A: Global MASTER-Net observations report
  91. EP241217a: Liverpool Telescope optical upper limit
  92. GRB 241218A: Mondy AZT-33IK optical upper limit
  93. EP241217a : Leavitt Observatory optical upper limit
  94. EP241217a: 1.6m Mephisto multi-band optical observations
  95. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  96. GRB 241218A: Swift/UVOT Upper Limits
  97. EP241217a: optical upper limit with the Liverpool Telescope
  98. Konus-Wind detection of GRB 241204A (short/hard)
  99. GRB 241218A: NOT optical upper limits
  100. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits

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