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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"

27774 results found.

  1. GRB 240825A: MeerKAT detection
  2. GRB 240828B: J-band upper limit from WINTER
  3. GRB 240828B: GMG Optical Upper Limit
  4. GRB 240828B: KAIT optical upper limit
  5. GRB 240829B: Fermi GBM Final Localization
  6. GRB 240828A: Fermi GBM Observation
  7. GRB 240825A: SVOM/VT optical detection
  8. GRB 240828A: Swift-XRT afterglow detection
  9. GRB 240828B: Swift-XRT afterglow detection
  10. GRB 240829A: Swift detection of a burst
  11. Swift GRB240829.16: Global MASTER-Net observations report
  12. GRB 240828A: Fermi-LAT detection
  13. GRB 240828A: Tiled Swift observations
  14. GRB 240828A: AstroSat CZTI detection of a long burst
  15. GRB 240825A: Upper limits from a neutrino search with IceCube
  16. GRB 240819A as a likely X-Ray Flash
  17. GRB 240828B: Swift ToO observations
  18. GRB 240825A: VLA detection
  19. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  20. GRB 240828A: Fermi GBM Final Real-time Localization
  21. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  22. GRB 240825A: GECAM detection
  23. GRB 240825A: ALMA detection
  24. GRB 240825A: SAO RAS optical observations
  25. GRB 240824A: GIT optical upper limit
  26. GRB 240819A: Swift afterglow confirmation
  27. GRB 240824B: Ondrejov D50 optical limit
  28. GRB 240825A: PRIME near-infrared detection
  29. Konus-Wind detection of GRB 240825A (bright/long)
  30. GRB 240825A: Fermi GBM Observation
  31. GRB 240825A: AKO Optical Follow-Up Observations
  32. GRB 240825A: AstroSat CZTI detection of the long bright burst
  33. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  34. GRB 240825A: Swift/UVOT Detection
  35. GRB 240825A: REM detection of the optical/NIR afterglow
  36. GRB 240825A: Swift-XRT refined Analysis
  37. GRB 240825A: VLT/X-shooter redshift
  38. GRB 240825A: SVOM/C-GFT optical observations
  39. GRB 240825A: Montarrenti Observatory optical observations
  40. GRB 240825A: Enhanced Swift-XRT position
  41. GRB 240825A: MASTER optical counterpart observation
  42. GRB 240825A: Fermi-LAT detection
  43. GRB 240825A: LCO optical observations
  44. GRB 240824B: KAIT optical upper limit
  45. GRB 240824B: Fermi GBM Observation
  46. GRB 240825A: GMG Optical Observation
  47. Swift GRB 240825A: Global MASTER-Net observations report
  48. GRB 240825A: 1.6m Mephisto multi-band detection
  49. GRB 240825A: AKO Optical Afterglow Detection
  50. GRB 240825A: Skynet Optical Afterglow observations
  51. GRB 240825A: Nanshan/HMT optical afterglow observations
  52. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  53. GRB 240825A: Fermi GBM Final Real-time Localization
  54. GRB 240824A: Swift-BAT refined analysis
  55. GRB 240824A: SVOM/C-GFT optical upper limit
  56. GRB 240824B: Swift-XRT afterglow detection
  57. GRB 240824A: Swift-XRT observations
  58. GRB 240824B: Swift/BAT arcminute localization of a burst
  59. GRB 240824B: Swift ToO observations
  60. GRB 240824C: Fermi GBM Final Localization
  61. GRB 240824A: Swift/UVOT Upper Limits
  62. GRB 240821A: Swift/UVOT observations of the XRT sources.
  63. GRB 240824B: MAXI/GSC detection
  64. GRB 240824B: Fermi GBM Final Real-time Localization
  65. GRB 240824A: Retraction of GCN 37255
  66. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  67. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  68. GRB 240824A: KAIT optical upper limit
  69. GRB 240824A: Skynet Optical Afterglow Discovery
  70. GRB 240824A: Swift detection of a burst
  71. Swift GRB240824.04: Global MASTER-Net observations report
  72. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  73. GRB 240821A: Colibri Optical Upper Limit
  74. EP240820a: PRIME J-band Observations
  75. GRB 240821A: Swift-XRT observations
  76. GRB 240822A: AstroSat CZTI detection of a short burst
  77. GRB 240821A: REM optical/NIR upper limits
  78. GRB 240821A: JinShan optical upper limits
  79. GRB 240809A: Mondy and AbAO Optical Observations
  80. GRB 240821A: SVOM/VT follow-up and optical upper limit
  81. GRB 240821A: GMG Optical Upper Limit
  82. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  83. GRB 240821A: Swift ToO observations
  84. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  85. GRB240821A: EIRSAT-1 GMOD Detection
  86. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  87. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  88. GRB 240821B: Fermi GBM Final Localization
  89. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  90. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  91. GRB 240821A: Fermi GBM Final Real-time Localization
  92. GRB 240819A: Swift-XRT observations
  93. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  94. EP240820a: EP detection of a fast X-ray transient
  95. GRB 240819A: KAIT optical upper limit
  96. EP240816a: PRIME upper limits
  97. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  98. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  99. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  100. GRB 240820A: Fermi GBM Final Real-time Localization

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