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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"
  1. GRB 240115A: Swift/BAT-GUANO detection of a short burst
  2. Swift Trigger 1209406 is not an astrophysical event
  3. Swift Triggers 1209401 and 1209403 are not astrophysical events
  4. IPN triangulation of GRB 240112A (long)
  5. Swift Triggers 1209371 through 1209374 are not astrophysical events
  6. Swift Triggers 1209369 and 1209370 are not astrophysical events
  7. GRB 240115B: AstroSat CZTI detection
  8. LIGO/Virgo/KAGRA S240109a: Upper limits from Swift/BAT-GUANO
  9. GRB 240115B: Fermi GBM Detection
  10. IceCube-240105A: ZTF optical observation of blazar PKS 0446+11
  11. GRB 240112D: Glowbug gamma-ray detection
  12. GRB 240112C: Glowbug gamma-ray detection
  13. GRB 240112C: VZLUSAT-2 detection
  14. GRB 240107A: VZLUSAT-2 detection
  15. Integral GRB240115.70: Global MASTER-Net observations report
  16. Fermi GRB 240115B: Global MASTER-Net observations report
  17. GRB 240115B: A long GRB detected by INTEGRAL
  18. GRB 240115B: Fermi GBM Final Real-time Localization
  19. Konus-Wind detection of GRB 240112C
  20. Fermi GRB 240115A: Global MASTER-Net observations report
  21. GRB 240115A: Fermi GBM Final Real-time Localization
  22. GRB 240112C: GRBAlpha detection
  23. GRB 240114A: MAXI/GSC detection
  24. GRB 240112C: Swift/UVOT Detection
  25. GRB 240112C: Fermi GBM Detection
  26. Fermi trigger No 726773850: Global MASTER-Net observations report
  27. GRB 240112C: Swift-XRT refined Analysis
  28. GRB 240112C: SAO RAS optical observations
  29. GRB 240112E: Fermi GBM Final Localization
  30. Fermi GRB 240112D: Global MASTER-Net observations report
  31. GRB 240112D: Fermi GBM Final Real-time Localization
  32. Fermi trigger No 726774492: Global MASTER-Net observations report
  33. Swift GRB 240112C: Global MASTER-Net observations report
  34. Fermi GRB 240112B: Global MASTER-Net observations report
  35. GRB 240109A: Swift-BAT refined analysis
  36. GRB 240112C: Swift detection of a burst with an optical counterpart
  37. GRB 240112B: Fermi GBM Final Real-time Localization
  38. GRB 240112A: GECAM detection of a burst
  39. GRB 240109A: Fermi GBM Observation
  40. GRB 240110A: AstroSat CZTI detection
  41. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  42. GRB 240108A: Glowbug gamma-ray detection
  43. GRB 231214A: ATCA Radio Upper Limits
  44. GRB 240106B: Glowbug gamma-ray detection
  45. GRB 240106A: Glowbug gamma-ray detection
  46. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  47. GRB 240109B: Fermi GBM Final Real-time Localization
  48. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  49. LIGO/Virgo/KAGRA S240109a: Updated Sky localization
  50. Konus-Wind detection of GRB 240101C
  51. GRB 231215A: radio detection with the VLA
  52. GRB 230818A: further radio observations with the VLA
  53. GRB 230812B: further radio observations with the VLA
  54. Swift GRB240109.17: Global MASTER-Net observations report
  55. GRB 240107A: AstroSat CZTI detection
  56. LIGO/Virgo/KAGRA S240109a: Identification of a GW compact binary merger candidate
  57. GRB 240109A: Swift detection of a short burst
  58. LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
  59. IceCube-240105A: JCMT SCUBA2 Detection of Two Bright Submillimeter Sources
  60. Update of IceCube-240105A - Corrected errors
  61. GRB 240106A: GRBAlpha detection
  62. LIGO/Virgo/KAGRA S240107b: Updated Sky localization and Source Classification
  63. GRB 240107A: MAXI/GSC detection
  64. Fermi trigger No 726347794: Global MASTER-Net observations report
  65. LIGO/Virgo/KAGRA S240107b: Identification of a GW compact binary merger candidate
  66. GRB 240106B: Fermi GBM Final Real-time Localization
  67. Fermi trigger No 726194053: Global MASTER-Net observations report
  68. GRB 240106A: Fermi GBM Final Real-time Localization
  69. IPN triangulation of GRB 240101C (short)
  70. GRB GRB240101C: Fermi GBM observation
  71. IceCube Alert 240105.52: Global MASTER-Net observations report
  72. GRB 240101A: 1.3m DFOT optical observations
  73. IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
  74. GRB 240102A: 1.3m DFOT optical upper limit
  75. GRB 240101B: 1.3m DFOT optical upper limit
  76. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  77. LIGO/Virgo/KAGRA S240104bl: Updated Sky localization
  78. LIGO/Virgo/KAGRA S240104bl: Identification of a GW compact binary merger candidate
  79. GRB 240102C: AstroSat CZTI detection
  80. GRB 240101C: AstroSat CZTI detection
  81. GRB 231220A: Swift-UVOT upper limit
  82. GRB 240102A: Swift-BAT refined analysis
  83. GRB 240102A: Swift/UVOT Upper Limits
  84. GRB 231230A: Swift-BAT refined analysis
  85. GRB 240101A: Swift-BAT refined analysis
  86. GRB 240101B: Swift-BAT refined analysis
  87. GRB 240102A: Enhanced Swift-XRT position
  88. GRB 240101B: Swift-XRT refined Analysis
  89. GRB 240102A: Swift-XRT refined Analysis
  90. GRB 240102B (Fermi GBM trigger 725926335/240102925) is not a GRB
  91. GRB 240102A: LCOGT Optical Upper Limits
  92. Fermi trigger No 725857207: Global MASTER-Net observations report
  93. GRB240102A: BOOTES-6/DPRT optical upper limit
  94. GRB 240102B: Fermi GBM Final Real-time Localization
  95. GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  96. IceCube-Cascade 231230A: Upper limits from a search for additional neutrino events in IceCube
  97. GRB 240102A: Swift detection of a burst
  98. GRB 240101A: Terskol Zeiss-2000 optical observations
  99. GRB 240101C: GRBAlpha detection
  100. GRB 240101B: Swift/UVOT Upper Limits

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