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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

3735 results found.

  1. GRB 241217A/EP241217b: SOAR afterglow detection
  2. GRB 241217A/EP241217B: Fermi-GBM Sub-Threshold Detection
  3. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  4. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  5. EP241217a: Liverpool Telescope optical follow-up
  6. EP241217a: Global MASTER-Net observations report
  7. GRB 241217A: GMG Optical Upper Limit
  8. GRB 241217A : SVOM/ECLAIRs,GRM,MXT detection of a long burst with a bright X-ray afterglow candidate
  9. GRB 241213B: Swift-XRT observations
  10. GRB 241213B: Tiled Swift observations
  11. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  12. GRB 241213B: MAXI/GSC detection
  13. EP241208a: Global MASTER-Net observations report
  14. Fermi GRB 241209E: Global MASTER-Net observations report
  15. Fermi GRB 241209A: Global MASTER-Net observations report
  16. GRB 241207C: MASTER optical observations
  17. GRB 241207C: Tiled Swift observations
  18. GRB 241207C: MAXI/GSC detection
  19. Fermi GRB 241206A: Global MASTER-Net observations report
  20. Fermi GRB 241204A: Global MASTER-Net observations report
  21. Fermi GRB 241201A: Global MASTER-Net observations report
  22. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  23. GRB 241127A: Swift-BAT refined analysis
  24. GRB 241026A: radio detection with the VLA
  25. GRB241120A: OHP/T193 optical observations
  26. GRB 241120A: Mondy and AbAO optical observations
  27. Fermi GRB 241118A: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  29. EP241113a: Global MASTER-Net observations report
  30. Fermi trigger No 753166198: Global MASTER-Net observations report
  31. Fermi-GBM Sub-Threshold Detection of GRB 241112B
  32. GRB 241112B: SVOM/GRM observation
  33. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  34. Fermi trigger No 752990530: Global MASTER-Net observations report
  35. Fermi trigger No 752878030: Global MASTER-Net observations report
  36. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  37. EP241107a: AKO Optical Afterglow Follow-Up Observations
  38. GRB 240511A: LCO upper limits
  39. Fermi GRB 241105A: Global MASTER-Net observations report
  40. Fermi GRB 241104A: Global MASTER-Net observations report
  41. EP241101a: EP-FXT observations update
  42. Fermi trigger No 752365806: Global MASTER-Net observations report
  43. EP241103a: Swift XRT detection and improved X-ray position
  44. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  45. GRB 241101A: Swift detection of a burst
  46. Fermi trigger No 752083996: Global MASTER-Net observations report
  47. EP EP241030a: Global MASTER-Net observations report
  48. Fermi trigger No 752006065: Global MASTER-Net observations report
  49. GRB 241030B: Swift detection of a burst
  50. GRB 240912A: radio detection with the VLA
  51. Fermi GRB 241030A: Global MASTER-Net observations report
  52. GRB 241026A: SAO RAS observations of possible optical afterglow
  53. Fermi GRB 241026A: Global MASTER-Net observations report
  54. GRB 241026A: Prompt enhanced Swift-XRT position
  55. EP241021a: optical follow-up observations with Xinglong Observatory
  56. Fermi GRB 241025A: Global MASTER-Net observations report
  57. IPN triangulation of GRB 241021A (long)
  58. GRB241017A: 1.3m DFOT optical upper limit
  59. Fermi trigger No 750788395: Global MASTER-Net observations report
  60. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  61. Fermi GRB 241016A: Global MASTER-Net observations report
  62. GRB 240916A: radio detection with the VLA
  63. GRB241013A: REM observations
  64. Fermi trigger No 750211959: Global MASTER-Net observations report
  65. IceCube Alert 241006.94: Global MASTER-Net observations report
  66. EP EP240930a: Global MASTER-Net observations report
  67. Fermi GRB 240929A: Global MASTER-Net observations report
  68. LIGO/Virgo S240919bn: GOTO optical upper limits
  69. GRB 240918B: AstroSat CZTI detection
  70. EP240919a: EP-FXT follow-up observation update
  71. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  72. GRB 240918B: Fermi GBM Detection
  73. GRB 240912A: Swift-BAT refined analysis
  74. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  75. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  76. Fermi GRB 240908A: Global MASTER-Net observations report
  77. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  78. GRB 240902B: AstroSat CZTI detection of a long burst
  79. GRB 240825A: Montarrenti Observatory optical follow-up observations
  80. Fermi trigger No 746923430: Global MASTER-Net observations report
  81. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  82. Fermi trigger No 746587425: Global MASTER-Net observations report
  83. Swift GRB240829.16: Global MASTER-Net observations report
  84. Fermi trigger No 746438824: Global MASTER-Net observations report
  85. GRB 240824A: GIT optical upper limit
  86. GRB 240824B: Ondrejov D50 optical limit
  87. GRB 240825A: AKO Optical Follow-Up Observations
  88. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  89. GRB 240824B: Fermi GBM Observation
  90. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  91. GRB 240824B: Swift-XRT afterglow detection
  92. GRB 240824B: Swift/BAT arcminute localization of a burst
  93. GRB 240824B: MAXI/GSC detection
  94. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  95. Fermi GRB 240821B: Global MASTER-Net observations report
  96. Fermi trigger No 745866488: Global MASTER-Net observations report
  97. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  98. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  99. Fermi GRB 240814B: Global MASTER-Net observations report
  100. GRB 240808A: AstroSat CZTI detection

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