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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"

44433 results found.

  1. GRB 240529A: Swift-BAT refined analysis
  2. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  3. GRB 240529A: Swift-XRT refined Analysis
  4. GRB240529A: BOOTES-6/DPRT optical detection
  5. GRB 240529A: Swift/UVOT Detection
  6. GRB 240529A: NOT optical observations
  7. GRB 240529A: AstroSat CZTI detection
  8. GRB 240529A: GOTO optical afterglow detection
  9. GRB 240527B: Swift-XRT afterglow detection
  10. GRB 240529A: Enhanced Swift-XRT position
  11. GRB 240529A: Swift detection of a burst with an optical counterpart
  12. Swift GRB240529.12: Global MASTER-Net observations report
  13. LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
  14. GRB 240527B: Fermi GBM Observation
  15. Fermi GRB 240527A: Global MASTER-Net observations report
  16. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  17. GRB 240527B: Fermi-LAT detection
  18. LAT GRB240527.59: Global MASTER-Net observations report
  19. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  20. Fermi GRB 240527B: Global MASTER-Net observations report
  21. GRB 240527B: Fermi GBM Final Localization
  22. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  23. GRB 240527A: Fermi GBM Final Real-time Localization
  24. GRB 240523A: Swift-BAT refined analysis
  25. Fermi trigger No 738348224: Global MASTER-Net observations report
  26. Fermi trigger No 738330463: Global MASTER-Net observations report
  27. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  28. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  29. GRB 240523A: Swift-XRT refined Analysis
  30. GRB 240523A: Enhanced Swift-XRT position
  31. GRB 240523A: Swift detection of a burst
  32. GRB 240521B: Fermi GBM Observation
  33. Fermi GBM Sub-Threshold Detection of GRB 240516B
  34. GRB 240513A: Swift-XRT afterglow detection
  35. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  36. Fermi trigger No 737996942: Global MASTER-Net observations report
  37. LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
  38. EP240518a: GSP optical upper limit
  39. GRB 240521A: GECAM-B detection of a long burst
  40. GRB 240516B: AstroSat CZTI detection
  41. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  42. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  43. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  44. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  45. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  46. GRB 240514B: VZLUSAT-2 detection
  47. GRB 240504A: VZLUSAT-2 detection
  48. GRB 240502A: VZLUSAT-2 detection
  49. GRB 240519A: GRBAlpha detection
  50. GRB 240516A: Swift/UVOT Upper Limits
  51. GRB 240519A: AstroSat CZTI detection
  52. Fermi trigger No 737788024: Global MASTER-Net observations report
  53. EP240518a: possibly identified with a flare star by EP-FXT
  54. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  55. EP240518a: EP-WXT detection of a new X-ray transient
  56. LIGO/Virgo/KAGRA S240514c: Updated Sky localization
  57. GRB 240516A: Swift-BAT refined analysis
  58. Fermi GRB 240517A: Global MASTER-Net observations report
  59. GRB 240516A ATCA radio observations
  60. IPN triangulation of GRB 240514B (short)
  61. GRB 240513A: Swift ToO observations
  62. GRB 240517A: Fermi GBM Final Real-time Localization
  63. Konus-Wind detection of GRB 240513A
  64. GRB 240516A: AstroSat CZTI detection
  65. GRB 240516A: Swift-XRT refined Analysis
  66. GRB 240514E: A possible candidate BD-21 1074
  67. Fermi trigger No 737559855: Global MASTER-Net observations report
  68. GRB 240516A: Fermi GBM Observation
  69. GRB 240511A: Observations from GTC/OSIRIS+
  70. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  71. GRB 240516A: GOTO optical upper limit
  72. LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
  73. Fermi trigger No 737523389: Global MASTER-Net observations report
  74. GRB 240516A: Swift detection of a burst
  75. Swift GRB240516.15: Global MASTER-Net observations report
  76. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  77. Fermi trigger No 737476171: Global MASTER-Net observations report
  78. GRB 240511A: radio detection of afterglow candidate
  79. GRB 240514B: GOTO candidate optical counterpart
  80. MAXI GRB240514.78: Global MASTER-Net observations report
  81. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  82. GRB 240514E: MAXI/GSC detection of a probable afterglow
  83. GRB 240514B: GRBAlpha detection
  84. LIGO/Virgo/KAGRA S240514x: Updated Sky localization
  85. LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
  86. GRB 240514B: Fermi GBM Detection
  87. LIGO/Virgo/KAGRA S240422ed: Las Cumbres Observatory Follow-up Observations of the Localization Region
  88. GRB 240513A: Fermi GBM observation
  89. GRB 240513A: Swift-XRT observations
  90. LIGO/Virgo/KAGRA S240513ei: Updated Sky localization
  91. LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate
  92. GRB 240514D: AstroSat CZTI detection
  93. GRB 240514C: Fermi GBM Final Real-time Localization
  94. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  95. Fermi GRB 240514B: Global MASTER-Net observations report
  96. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  97. GRB 240514B: Fermi GBM Final Real-time Localization
  98. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  99. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  100. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO

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