Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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').
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"

12332 results found.

  1. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  2. Swift GRB250129A: MASTER 4 days observations report
  3. LIGO/Virgo/KAGRA S250201i: Coverage and upper limits from MAXI/GSC observations
  4. EP250108A / SN 2025kg: Upper limits from a neutrino search with IceCube
  5. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  6. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  7. GRB 250128B: VLA radio upper limit
  8. Ep250125A: 1.3m DFOT optical upper limit
  9. GRB 250128B: TNG optical upper limit
  10. GRB 250127A: CrAO and Terskol optical upper limits
  11. GRB 250128B: NOT optical upper limit
  12. GRB 250128B: OHP/T193 optical upper limit
  13. Swift GRB 250129A: Global MASTER-Net observations report
  14. Fermi GRB 250128B: Global MASTER-Net observations report
  15. Swift GRB 250129A: Global MASTER-Net OT detection
  16. GRB 250128B: GOTO optical upper limit
  17. Swift GRB 250128B: Global MASTER-Net observations report
  18. EP250125a: Upper limits from Swift/BAT-GUANO
  19. GRB 250128B: Swift detection of a short burst
  20. GRB 250127A: Swift-XRT observations
  21. GRB 250127B: DDOTI Upper Limit on the Afterglow
  22. Fermi-LAT Gamma-ray Observations of IceCube-250102A
  23. Fermi GRB 250128A: Global MASTER-Net observations report
  24. Fermi GRB 250127B: Global MASTER-Net observations report
  25. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  26. GRB 250127A: SVOM/VT upper limit
  27. GRB 250127A: LCO optical upper limit
  28. GRB 250126A: MAXI/GSC detection
  29. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  30. EP250125a: Optical upper limit with Kinder observations
  31. EP250108a: AbAO, CMO and Terskol optical upper limits
  32. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  33. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  34. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  35. EP250108a / AT2025kg: VLA radio upper limit
  36. GRB 250114B: SVOM/VT upper limit
  37. EP250108a: MeerKAT radio upper limit
  38. Konus-Wind detection of GRB 250113A
  39. GRB 250114B: Liverpool Telescope optical upper limit
  40. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  41. GRB 250114B: Swift-XRT observations
  42. GRB 250114B: OHP/T193 optical upper limit
  43. Integral GRB250114.55: Global MASTER-Net observations report
  44. GRB 250114B : GIT optical upper limit
  45. EP250111a: SAO RAS optical upper limit
  46. Swift GRB250114A: Global MASTER-Net OT detection
  47. Swift GRB 250114A: Global MASTER-Net observations report
  48. EP241021a: SMA radio observation
  49. EP250109b: optical upper limits with the Liverpool Telescope
  50. Fermi trigger No 758442826: Global MASTER-Net observations report
  51. GRB 250109A / EP250109a: Mephisto optical upper limits
  52. EP250108a: Mephisto detection
  53. EP250111a: Global MASTER-Net observations report
  54. EP250108a / AT 2025kg: Swift UVOT detections
  55. EP250108a: EP-FXT follow-up observation
  56. GRB 250109a: GMG Optical Upper Limit
  57. EP250109a: Swift/UVOT non-detection
  58. GRB 250108B: 1.3m DFOT upper limit
  59. GRB 250108B: REM optical/NIR upper limits
  60. EP250109a: SVOM/VT optical candidate
  61. EP250109a: Global MASTER-Net observations report
  62. EP250109a: GOTO optical upper limits
  63. EP250109a: Swift/XRT non-detection
  64. GRB 250108A: Swift/UVOT Upper Limits
  65. EP250108a: Global MASTER-Net observations report
  66. GRB 250108A: NOT optical upper limit
  67. Swift GRB 250108B: Global MASTER-Net observations report
  68. GRB 250103A: 1.6m Mephisto optical observations
  69. GRB 250108A: Swift-XRT afterglow detection
  70. GRB 250108B: Swift/UVOT Upper Limits
  71. GRB 250108B: Swift detection of a burst
  72. Fermi GRB 250107B: Global MASTER-Net observations report
  73. GRB 250101A: J band upper limit by SYSU 80cm telescope
  74. GRB 250103B: REM optical/NIR upper limits
  75. GRB 250106A: Swift-XRT observations
  76. Fermi trigger No 757753930: Global MASTER-Net observations report
  77. GRB 250103A: Bassano Bresciano Observatory upper limit
  78. GRB 250103A: Swift-XRT observations
  79. GRB 241229A: 1.3m DFOT upper limit
  80. GRB 241228A: 1.3m DFOT upper limit
  81. GRB 250103A: TSHAO optical upper limit
  82. GRB 250103B: LCOGT Optical Upper Limit
  83. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  84. Swift GRB 250103B: Global MASTER-Net observations report
  85. EP250101a: Liverpool Telescope optical upper limit
  86. IceCube-250101A: Upper limits from a search for additional neutrino events in IceCube
  87. Fermi GRB 250102A: Global MASTER-Net observations report
  88. GRB 250103A: GOTO optical upper limit
  89. GRB 250103A: SVOM/C-GFT optical upper limit
  90. GRB 250101A: NUTTelA-TAO / BSTI Optical Limits
  91. IceCube Alert 250102.58: Global MASTER-Net observations report
  92. EP241231b: optical upper limit with the Liverpool Telescope
  93. EP250101a: Xinglong optical upper limit
  94. LIGO/Virgo/KAGRA S241230bd: Upper limits from Swift/BAT-GUANO
  95. GRB 250101A: Swift/UVOT Detection
  96. Fermi GRB 250101B: Global MASTER-Net observations report
  97. LIGO/Virgo/KAGRA S250101k: Upper limits from Fermi-GBM Observations
  98. Swift GRB250101.56: Global MASTER-Net observations report
  99. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  100. EP241217A: J band upper limit by SYSU 80cm telescope

Advanced

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