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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"

45423 results found.

  1. GRB 240828B: GRANDMA Optical Upper Limit
  2. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
  4. GRB 240829A: Swift-BAT refined analysis
  5. GRB 240825A: Swift-BAT refined analysis
  6. LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
  7. GRB 240825A: MeerKAT detection
  8. GRB 240828B: J-band upper limit from WINTER
  9. Fermi trigger No 746684112: Global MASTER-Net observations report
  10. GRB 240828B: GMG Optical Upper Limit
  11. GRB 240828A: KAIT continued optical observations
  12. GRB 240828B: GWAC-F50A optical upper limit
  13. GRB 240828B: SVOM/C-GFT optical upper limit
  14. GRB 240828B: SAO RAS optical upper limit
  15. GRB 240828B: KAIT optical upper limit
  16. GRB 240828A: SAO RAS optical observations
  17. Fermi trigger No 746587425: Global MASTER-Net observations report
  18. GRB 240829B: Fermi GBM Final Localization
  19. GRB 240828A: Fermi GBM Observation
  20. GRB 240629A: First GRB Detected by BurstCube
  21. GRB 240828A: KAIT Optical Afterglow Candidate
  22. GRB 240825A: SVOM/VT optical detection
  23. GRB 240828A: Swift-XRT afterglow detection
  24. GRB 240825A: further SAO RAS optical observations
  25. GRB 240825A: iTelescope optical observations
  26. GRB 240828B: Swift-XRT afterglow detection
  27. GRB 240829A: Swift detection of a burst
  28. Swift GRB240829.16: Global MASTER-Net observations report
  29. GRB 240828A: Fermi-LAT detection
  30. GRB 240828A: Tiled Swift observations
  31. LAT GRB240828.62: Global MASTER-Net observations report
  32. GRB 240828A: AstroSat CZTI detection of a long burst
  33. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  34. GRB 240825A: Upper limits from a neutrino search with IceCube
  35. GRB 240819A as a likely X-Ray Flash
  36. GRB 240828B: Swift ToO observations
  37. GRB 240821A: PRIME near-infrared observations
  38. GRB 240825A: VLA detection
  39. Fermi GRB 240828A: Global MASTER-Net observations report
  40. Fermi trigger No 746438824: Global MASTER-Net observations report
  41. SVOM GRB 240821A: optical afterglow discovery
  42. GRB 240828B : Detection of a possible very soft X-ray transient by SVOM/ECLAIRs
  43. GRB 240828A: Fermi GBM Final Real-time Localization
  44. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  45. GRB 240825A: GECAM detection
  46. GRB 240825A: ALMA detection
  47. GRB 240825A: SAO RAS optical observations
  48. GRB 240824A: GIT optical upper limit
  49. GRB 240819A: Swift afterglow confirmation
  50. GRB 240825A: TNG optical photometry and spectroscopy
  51. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  52. LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
  53. GRB 240825A: NUTTelA-TAO / BSTI Optical Limits
  54. GRB 240825A: GMG Continued Optical Observation on the Second Night
  55. GRB 240824B: Ondrejov D50 optical limit
  56. GRB 240825A: KAIT optical observations
  57. GRB 240825A: PRIME near-infrared detection
  58. Konus-Wind detection of GRB 240825A (bright/long)
  59. GRB 240825A: Fermi GBM Observation
  60. GRB 240825A : MISTRAL/T193 OHP optical follow-up of the afterglow
  61. GRB 240825A: AKO Optical Follow-Up Observations
  62. GRB 240825A: AstroSat CZTI detection of the long bright burst
  63. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  64. GRB 240825A: Swift/UVOT Detection
  65. GRB 240825A: REM detection of the optical/NIR afterglow
  66. GRB 240825A: Swift-XRT refined Analysis
  67. GRB 240825A: VLT/X-shooter redshift
  68. GRB 240825A: SVOM/C-GFT optical observations
  69. GRB 240825A: Montarrenti Observatory optical observations
  70. GRB 240825A: Enhanced Swift-XRT position
  71. GRB 240825A: MASTER optical counterpart observation
  72. GRB 240825A: Fermi-LAT detection
  73. GRB 240825A: LCO optical observations
  74. GRB 240824B: KAIT optical upper limit
  75. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  76. GRB 240824B: Fermi GBM Observation
  77. Fermi GRB 240825A: Global MASTER-Net observations report
  78. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  79. GRB 240824B: NOT optical upper limit
  80. GRB 240825A: GMG Optical Observation
  81. Swift GRB 240825A: Global MASTER-Net observations report
  82. GRB 240825A: 1.6m Mephisto multi-band detection
  83. GRB 240825A: AKO Optical Afterglow Detection
  84. GRB 240825A: Skynet Optical Afterglow observations
  85. GRB 240825A: Nanshan/HMT optical afterglow observations
  86. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  87. GRB 240825A: Fermi GBM Final Real-time Localization
  88. GRB 240824A: Swift-BAT refined analysis
  89. GRB 240824A: SVOM/C-GFT optical upper limit
  90. GRB 240824B: Swift-XRT afterglow detection
  91. GRB 240824A: Swift-XRT observations
  92. LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
  93. GRB 240824B: Swift/BAT arcminute localization of a burst
  94. GRB 240824B: Swift ToO observations
  95. Fermi GRB 240824C: Global MASTER-Net observations report
  96. GRB 240824C: Fermi GBM Final Localization
  97. GRB 240824A: Swift/UVOT Upper Limits
  98. GRB 240821A: Swift/UVOT observations of the XRT sources.
  99. GRB 240824B: MAXI/GSC detection
  100. GRB 240824B: Fermi GBM Final Real-time Localization

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