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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"

35953 results found.

  1. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  2. GRB 230906A: Swift-XRT observations
  3. Konus-Wind detection of GRB 230906A (short)
  4. IPN triangulation of GRB 230906A (short)
  5. GRB 230906A: Swift ToO observations
  6. GRB 230905B: AstroSat CZTI detection
  7. Fermi GRB 230906A: Global MASTER-Net observations report
  8. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  9. GRB 230906A: Fermi GBM Final Localizationn
  10. GRB 230905B: GECAM-C detection of a long burst
  11. GRB 230905A: Fermi GBM Final Real-time Localization
  12. GRB 230903A: Swift-XRT refined Analysis
  13. GRB 230903A: Enhanced Swift-XRT position
  14. GRB 230903A: VLT/X-shooter optical observations
  15. GRB 230903A: Swift-BAT refined analysis
  16. GRB 230904C: Fermi GBM Final Localization
  17. Fermi GRB 230903A: Global MASTER-Net observations report
  18. GRB 230903A: Fermi GBM detection
  19. GRB 230904B is not a GRB
  20. GRB 230904B: BALROG localization (Fermi Trigger 715526984 / GRB 230904562)
  21. Fermi GRB 230904A: Global MASTER-Net observations report
  22. GRB 230904A: Fermi GBM Final Real-time Localization
  23. GRB 230903A: LCOGT Optical Upper Limits
  24. GRB 230903A: Swift detection of a burst
  25. GRB 230903A: Fermi GBM Final Real-time Localization
  26. GRB 230827B: Glowbug gamma-ray detection
  27. GRB 230827A: Glowbug gamma-ray detection
  28. GRB 230826A: Glowbug gamma-ray detection
  29. GRB 230827B: Swift-XRT afterglow detection
  30. GRB 230812B: Spectroscopic detection of the associated SN 2023pel.
  31. GRB 230827B: Swift ToO observations
  32. GRB 230827A: Fermi GBM Observation
  33. GRB 230827B: CALET Gamma-Ray Burst Monitor detection
  34. GRB 230826A: Swift-BAT refined analysis
  35. GRB 230828A: AstroSat CZTI detection
  36. GRB 230828A: GRBAlpha detection
  37. Swift Trigger 1188089 is not a GRB
  38. GRB 230827A: VZLUSAT-2 detection
  39. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  40. GRB 230826A: VZLUSAT-2 detection
  41. GRB 230827B: VZLUSAT-2 detection
  42. GRB 230827B / GRB 230827256: Fermi GBM Observation
  43. GRB 230827A: GRBAlpha detection
  44. Subject: GRB230826A: Swift/UVOT upper limits
  45. GRB 230827A: BALROG localization (Fermi Trigger / GRB 230827762)
  46. GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
  47. Fermi GRB 230827A: Global MASTER-Net observations report
  48. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  49. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  50. GRB 230827A: Fermi GBM Final Real-time Localization
  51. AT 2023qxj: ZTF discovery of the likely afterglow of Fermi GRB 230827256
  52. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  53. GRB 230826A: GRBAlpha detection
  54. GRB 230826A: Fermi GBM Observation
  55. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  56. GRB 230826A: Enhanced Swift-XRT position
  57. GRB 230826A: Swift-XRT refined Analysis
  58. GRB 230826A: Mondy optical observations
  59. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  60. GRB 230826A: Swift detection of a burst
  61. GRB 230826A: Fermi GBM Final Real-time Localization
  62. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  63. GRB 230824A: AKO Photometric Follow-up Observations
  64. GRB 230818B: CALET Gamma-Ray Burst Monitor detection
  65. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  66. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  67. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  68. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  69. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  70. GRB 230812B: radio detection with the VLA
  71. Fermi Gamma-ray Burst Monitor trigger 714618399/230825046 is not a GRB
  72. NICER detection of Swift J1727.8-1613 (GRB 230824A)
  73. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  74. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  75. GRB 230824A: AKO Optical Afterglow Candidate
  76. Trigger 1186982: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  77. IBAS trigger 10375 is not a GRB
  78. GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
  79. GRB 230824B: AstroSat CZTI detection
  80. GRB 230824A: Swift detection of a burst
  81. Swift Trigger 1186908 is not a GRB
  82. GRB 230822A: Fermi GBM Observation
  83. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  84. GRB 230822A: Swift/BAT-GUANO detection of a burst
  85. GRB 230812B: AstroSat LAXPC detection
  86. GRB 230818B: VZLUSAT-2 detection
  87. GRB 230818B: AstroSat CZTI detection
  88. GRID detection of GRB 230818A
  89. GRB 230822A: Fermi GBM Final Real-time Localization
  90. GRB 230812B: Assy optical observations, possible SN rise
  91. GRB 230815A: ATCA detection of radio counterpart
  92. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  93. GRB 230818A: Swift-BAT refined analysis
  94. GRB 20230818A: GIT optical upper limit
  95. Swift Trigger 1186391 is not a GRB
  96. Swift Trigger 1186390 is not a GRB
  97. Konus-Wind detection of GRB 230818A
  98. Swift Trigger 1186386 is not a GRB
  99. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  100. GRB 230820A: AstroSat CZTI detection

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