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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"

39190 results found.

  1. GRB 240819A as a likely X-Ray Flash
  2. GRB 240828B: Swift ToO observations
  3. GRB 240821A: PRIME near-infrared observations
  4. GRB 240825A: VLA detection
  5. Fermi GRB 240828A: Global MASTER-Net observations report
  6. Fermi trigger No 746438824: Global MASTER-Net observations report
  7. SVOM GRB 240821A: optical afterglow discovery
  8. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  9. GRB 240828A: Fermi GBM Final Real-time Localization
  10. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  11. GRB 240825A: GECAM detection
  12. GRB 240825A: ALMA detection
  13. GRB 240825A: SAO RAS optical observations
  14. GRB 240824A: GIT optical upper limit
  15. GRB 240819A: Swift afterglow confirmation
  16. GRB 240825A: TNG optical photometry and spectroscopy
  17. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  18. GRB 240825A: GMG Continued Optical Observation on the Second Night
  19. GRB 240824B: Ondrejov D50 optical limit
  20. GRB 240825A: KAIT optical observations
  21. GRB 240825A: PRIME near-infrared detection
  22. Konus-Wind detection of GRB 240825A (bright/long)
  23. GRB 240825A: Fermi GBM Observation
  24. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  25. GRB 240825A: AKO Optical Follow-Up Observations
  26. GRB 240825A: AstroSat CZTI detection of the long bright burst
  27. GRB 240825A: Swift/UVOT Detection
  28. GRB 240825A: REM detection of the optical/NIR afterglow
  29. GRB 240825A: Swift-XRT refined Analysis
  30. GRB 240825A: VLT/X-shooter redshift
  31. GRB 240825A: SVOM/C-GFT optical observations
  32. GRB 240825A: Montarrenti Observatory optical observations
  33. GRB 240825A: Enhanced Swift-XRT position
  34. GRB 240825A: MASTER optical counterpart observation
  35. GRB 240825A: Fermi-LAT detection
  36. GRB 240825A: LCO optical observations
  37. GRB 240824B: KAIT optical upper limit
  38. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  39. GRB 240824B: Fermi GBM Observation
  40. Fermi GRB 240825A: Global MASTER-Net observations report
  41. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  42. GRB 240824B: NOT optical upper limit
  43. GRB 240825A: GMG Optical Observation
  44. Swift GRB 240825A: Global MASTER-Net observations report
  45. GRB 240825A: 1.6m Mephisto multi-band detection
  46. GRB 240825A: AKO Optical Afterglow Detection
  47. GRB 240825A: Skynet Optical Afterglow observations
  48. GRB 240825A: Nanshan/HMT optical afterglow observations
  49. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  50. GRB 240825A: Fermi GBM Final Real-time Localization
  51. GRB 240824A: Swift-BAT refined analysis
  52. GRB 240824A: SVOM/C-GFT optical upper limit
  53. GRB 240824B: Swift-XRT afterglow detection
  54. GRB 240824A: Swift-XRT observations
  55. GRB 240824B: Swift/BAT arcminute localization of a burst
  56. GRB 240824B: Swift ToO observations
  57. Fermi GRB 240824C: Global MASTER-Net observations report
  58. GRB 240824C: Fermi GBM Final Localization
  59. GRB 240824A: Swift/UVOT Upper Limits
  60. GRB 240821A: Swift/UVOT observations of the XRT sources.
  61. GRB 240824B: MAXI/GSC detection
  62. GRB 240824B: Fermi GBM Final Real-time Localization
  63. GRB 240824A: Retraction of GCN 37255
  64. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  65. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  66. GRB 240824A: KAIT optical upper limit
  67. GRB 240824A: Skynet Optical Afterglow Discovery
  68. GRB 240824A: Swift detection of a burst
  69. Swift GRB240824.04: Global MASTER-Net observations report
  70. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  71. GRB 240821A: Colibri Optical Upper Limit
  72. EP240820a: PRIME J-band Observations
  73. GRB 240821A: Swift-XRT observations
  74. GRB 240822A: AstroSat CZTI detection of a short burst
  75. GRB 240821A: REM optical/NIR upper limits
  76. GRB 240821A: LCO optical observations
  77. GRB 240821A: JinShan optical upper limits
  78. GRB 240809A: Mondy and AbAO Optical Observations
  79. GRB 240821A: SVOM/VT follow-up and optical upper limit
  80. GRB 240821A: GMG Optical Upper Limit
  81. Fermi GRB 240821A: Global MASTER-Net observations report
  82. GRB 240821A: Fermi GBM Observation
  83. Fermi trigger No 745964969: Global MASTER-Net observations report
  84. Fermi trigger No 745925274: Global MASTER-Net observations report
  85. GRB 240821A: Swift ToO observations
  86. Fermi trigger No 746019401: Global MASTER-Net observations report
  87. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  88. Fermi trigger No 745935375: Global MASTER-Net observations report
  89. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  90. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  91. Fermi GRB 240821B: Global MASTER-Net observations report
  92. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  93. GRB 240821A: SVOM/GRM observation
  94. GRB 240821A: SVOM/GRM observation
  95. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  96. GRB 240821B: Fermi GBM Final Localization
  97. Fermi trigger No 745866488: Global MASTER-Net observations report
  98. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  99. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  100. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs

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