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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"

35982 results found.

  1. GRB 230906A: Chandra detection of the X-ray afterglow
  2. Swift GRB 230911C: Global MASTER-Net observations report
  3. GRB 230911D: Fermi GBM observation
  4. IPN triangulation of GRB 230911D (long)
  5. GRB 230911D: Fermi-LAT detection
  6. GRB230911C: LCOGT Optical Upper Limits
  7. GRB 230911C: Swift/UVOT Upper Limits
  8. GRB 230911B: GRBAlpha and VZLUSAT-2 joint detection
  9. GRB 230911C: GOTO optical upper limits
  10. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  11. GRB 230911B: correction to the KW GCN 34659
  12. Konus-Wind detection of GRB 230811D
  13. GRB 230911C: Enhanced Swift-XRT position
  14. GRB 230911D: BALROG localization (Fermi Trigger 716111594/ GRB 230911329)
  15. GRB 230911D: Fermi GBM Final Localization
  16. GRB 230911C: Swift detection of a burst
  17. Fermi GRB 230911B: Global MASTER-Net observations report
  18. GRB 230911B: Fermi GBM Final Real-time Localization
  19. GRB 230911A: Fermi GBM Final Real-time Localization
  20. GRB 230906A: BlackGEM upper limits
  21. GRB 230903A: TESS observations of optical emission
  22. GRB 230906A: AstroSat CZTI detection
  23. GRB 230910A: Fermi GBM Final Real-time Localization
  24. GRB 230908A: GRBAlpha detection
  25. GRB 230908A: AstroSat CZTI detection
  26. Glowbug gamma-ray detection GRB 230905B
  27. GRB 230906A: Swift/UVOT Upper Limits
  28. GRID detection of GRB 230827A
  29. GRB 230818A: radio observation with the VLA
  30. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  31. GRB 230906A: Swift-XRT observations
  32. Konus-Wind detection of GRB 230906A (short)
  33. IPN triangulation of GRB 230906A (short)
  34. GRB 230906A: Swift ToO observations
  35. GRB 230905B: AstroSat CZTI detection
  36. Fermi GRB 230906A: Global MASTER-Net observations report
  37. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  38. GRB 230906A: Fermi GBM Final Localizationn
  39. GRB 230905B: GECAM-C detection of a long burst
  40. GRB 230905A: Fermi GBM Final Real-time Localization
  41. GRB 230903A: Swift-XRT refined Analysis
  42. GRB 230903A: Enhanced Swift-XRT position
  43. GRB 230903A: VLT/X-shooter optical observations
  44. GRB 230903A: Swift-BAT refined analysis
  45. GRB 230904C: Fermi GBM Final Localization
  46. Fermi GRB 230903A: Global MASTER-Net observations report
  47. GRB 230903A: Fermi GBM detection
  48. GRB 230904B is not a GRB
  49. GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
  50. Fermi GRB 230904A: Global MASTER-Net observations report
  51. GRB 230904A: Fermi GBM Final Real-time Localization
  52. GRB 230903A: LCOGT Optical Upper Limits
  53. GRB 230903A: Swift detection of a burst
  54. GRB 230903A: Fermi GBM Final Real-time Localization
  55. GRB 230827B: Glowbug gamma-ray detection
  56. GRB 230827A: Glowbug gamma-ray detection
  57. GRB 230826A: Glowbug gamma-ray detection
  58. GRB 230827B: Swift-XRT afterglow detection
  59. GRB 230812B: Spectroscopic detection of the associated SN 2023pel.
  60. GRB 230827B: Swift ToO observations
  61. GRB 230827A: Fermi GBM Observation
  62. GRB 230827B: CALET Gamma-Ray Burst Monitor detection
  63. GRB 230826A: Swift-BAT refined analysis
  64. GRB 230828A: AstroSat CZTI detection
  65. GRB 230828A: GRBAlpha detection
  66. Swift Trigger 1188089 is not a GRB
  67. GRB 230827A: VZLUSAT-2 detection
  68. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  69. GRB 230826A: VZLUSAT-2 detection
  70. GRB 230827B: VZLUSAT-2 detection
  71. GRB 230827B / GRB 230827256: Fermi GBM Observation
  72. GRB 230827A: GRBAlpha detection
  73. Subject: GRB230826A: Swift/UVOT upper limits
  74. GRB 230827A: BALROG localization (Fermi Trigger / GRB 230827762)
  75. GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
  76. Fermi GRB 230827A: Global MASTER-Net observations report
  77. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  78. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  79. GRB 230827A: Fermi GBM Final Real-time Localization
  80. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  81. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  82. GRB 230826A: GRBAlpha detection
  83. GRB 230826A: Fermi GBM Observation
  84. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  85. GRB 230826A: Enhanced Swift-XRT position
  86. GRB 230826A: Swift-XRT refined Analysis
  87. GRB 230826A: Mondy optical observations
  88. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  89. GRB 230826A: Swift detection of a burst
  90. GRB 230826A: Fermi GBM Final Real-time Localization
  91. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  92. GRB 230824A: AKO Photometric Follow-up Observations
  93. GRB 230818B: CALET Gamma-Ray Burst Monitor detection
  94. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  95. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  96. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  97. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  98. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  99. GRB 230812B: radio detection with the VLA
  100. Fermi Gamma-ray Burst Monitor trigger 714618399/230825046 is not a GRB

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