Skip to main content
New Swift-BAT/GUANO and IceCube Notice Types Available! See news and announcements

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').
  1. GRB 240107A: VZLUSAT-2 detection
  2. Integral GRB240115.70: Global MASTER-Net observations report
  3. Fermi GRB 240115B: Global MASTER-Net observations report
  4. GRB 240115B: A long GRB detected by INTEGRAL
  5. GRB 240115B: Fermi GBM Final Real-time Localization
  6. Konus-Wind detection of GRB 240112C
  7. Fermi GRB 240115A: Global MASTER-Net observations report
  8. GRB 240115A: Fermi GBM Final Real-time Localization
  9. GRB 240112C: GRBAlpha detection
  10. GRB 240114A: MAXI/GSC detection
  11. GRB 240112C: Swift/UVOT Detection
  12. GRB 240112C: Fermi GBM Detection
  13. Fermi trigger No 726773850: Global MASTER-Net observations report
  14. GRB 240112C: Swift-XRT refined Analysis
  15. GRB 240112C: SAO RAS optical observations
  16. GRB 240112E: Fermi GBM Final Localization
  17. Fermi GRB 240112D: Global MASTER-Net observations report
  18. GRB 240112D: Fermi GBM Final Real-time Localization
  19. Fermi trigger No 726774492: Global MASTER-Net observations report
  20. Swift GRB 240112C: Global MASTER-Net observations report
  21. Fermi GRB 240112B: Global MASTER-Net observations report
  22. GRB 240109A: Swift-BAT refined analysis
  23. GRB 240112C: Swift detection of a burst with an optical counterpart
  24. GRB 240112B: Fermi GBM Final Real-time Localization
  25. GRB 240112A: GECAM detection of a burst
  26. GRB 240109A: Fermi GBM Observation
  27. GRB 240110A: AstroSat CZTI detection
  28. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  29. GRB 240108A: Glowbug gamma-ray detection
  30. GRB 231214A: ATCA Radio Upper Limits
  31. GRB 240106B: Glowbug gamma-ray detection
  32. GRB 240106A: Glowbug gamma-ray detection
  33. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  34. GRB 240109B: Fermi GBM Final Real-time Localization
  35. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  36. LIGO/Virgo/KAGRA S240109a: Updated Sky localization
  37. Konus-Wind detection of GRB 240101C
  38. GRB 231215A: radio detection with the VLA
  39. GRB 230818A: further radio observations with the VLA
  40. GRB 230812B: further radio observations with the VLA
  41. Swift GRB240109.17: Global MASTER-Net observations report
  42. GRB 240107A: AstroSat CZTI detection
  43. LIGO/Virgo/KAGRA S240109a: Identification of a GW compact binary merger candidate
  44. GRB 240109A: Swift detection of a short burst
  45. LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
  46. IceCube-240105A: JCMT SCUBA2 Detection of Two Bright Submillimeter Sources
  47. Update of IceCube-240105A - Corrected errors
  48. GRB 240106A: GRBAlpha detection
  49. LIGO/Virgo/KAGRA S240107b: Updated Sky localization and Source Classification
  50. GRB 240107A: MAXI/GSC detection
  51. Fermi trigger No 726347794: Global MASTER-Net observations report
  52. LIGO/Virgo/KAGRA S240107b: Identification of a GW compact binary merger candidate
  53. GRB 240106B: Fermi GBM Final Real-time Localization
  54. Fermi trigger No 726194053: Global MASTER-Net observations report
  55. GRB 240106A: Fermi GBM Final Real-time Localization
  56. IPN triangulation of GRB 240101C (short)
  57. GRB GRB240101C: Fermi GBM observation
  58. IceCube Alert 240105.52: Global MASTER-Net observations report
  59. GRB 240101A: 1.3m DFOT optical observations
  60. IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
  61. GRB 240102A: 1.3m DFOT optical upper limit
  62. GRB 240101B: 1.3m DFOT optical upper limit
  63. GRB 240101C: Swift/BAT-GUANO detection of a short burst
  64. LIGO/Virgo/KAGRA S240104bl: Updated Sky localization
  65. LIGO/Virgo/KAGRA S240104bl: Identification of a GW compact binary merger candidate
  66. GRB 240102C: AstroSat CZTI detection
  67. GRB 240101C: AstroSat CZTI detection
  68. GRB 231220A: Swift-UVOT upper limit
  69. GRB 240102A: Swift-BAT refined analysis
  70. GRB 240102A: Swift/UVOT Upper Limits
  71. GRB 231230A: Swift-BAT refined analysis
  72. GRB 240101A: Swift-BAT refined analysis
  73. GRB 240101B: Swift-BAT refined analysis
  74. GRB 240102A: Enhanced Swift-XRT position
  75. GRB 240101B: Swift-XRT refined Analysis
  76. GRB 240102A: Swift-XRT refined Analysis
  77. GRB 240102B (Fermi GBM trigger 725926335/240102925) is not a GRB
  78. GRB 240102A: LCOGT Optical Upper Limits
  79. Fermi trigger No 725857207: Global MASTER-Net observations report
  80. GRB240102A: BOOTES-6/DPRT optical upper limit
  81. GRB 240102B: Fermi GBM Final Real-time Localization
  82. GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  83. IceCube-Cascade 231230A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 240102A: Swift detection of a burst
  85. GRB 240101A: Terskol Zeiss-2000 optical observations
  86. GRB 240101C: GRBAlpha detection
  87. GRB 240101B: Swift/UVOT Upper Limits
  88. GRB 240101A: Swift/UVOT Upper Limits
  89. GRB 240101A: Swift-XRT refined Analysis
  90. GRB 240101B: Enhanced Swift-XRT position
  91. GRB 240101B: KAIT Optical Upper Limit
  92. GRB 240101A: KAIT Optical Upper Limit
  93. GRB 240101A: Enhanced Swift-XRT position
  94. GRB 240101C: Fermi GBM Final Localization
  95. Swift GRB240101.85: Global MASTER-Net observations report
  96. GRB 240101B: Swift detection of a burst
  97. GRB 240101A: Swift detection of a burst
  98. Fermi trigger No 725806648: Global MASTER-Net observations report
  99. LIGO/Virgo/KAGRA S231231ag: Updated Sky localization and Source Classification
  100. LIGO/Virgo/KAGRA S231231ag: Identification of a GW compact binary merger candidate

Advanced

Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit USA.gov