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"

32505 results found.

  1. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  2. GRB 251215A: Glowbug gamma-ray detection
  3. GRB 251214B: UAFO optical upper limit
  4. GRB 251214B: VLT/X-shooter observations
  5. GRB 251213A: GRID-10B observation
  6. GRB 251214B: Swift-BAT refined analysis
  7. GRB 251202A: radio detection with the VLA
  8. EP251214b: Global MASTER-Net observations report
  9. EP251214b : Einstein Probe detection of a fast X-ray transient
  10. EP251214b : Einstein Probe detection of a fast X-ray transient
  11. GRB 251214B: AbAO optical observations
  12. GRB 251214B: LCO detection of the optical counterpart
  13. GRB 251209A: GECAM-B observation of a long burst
  14. GRB 251214D: GECAM-B observation of a long burst
  15. GRB 251214B: Fermi GBM Observation
  16. GRB 251209A: Insight-HXMT/HE detection
  17. GRB 251215A: Swift ToO observations
  18. EP251214b (EP trigger 01709250023): LCO optical limits
  19. GRID detection of GRB 251213A
  20. GRB 251203B: AbAO optical observations
  21. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  22. GRB 251214B: GECAM-B observation of a long burst
  23. GRB 251213A: SVOM/GRM observation
  24. EP251214a: KAIT optical upper limit
  25. GRB 251213A: AstroSat CZTI detection
  26. GRB 251214A: AstroSat CZTI detection
  27. GRB 251214B: Swift/UVOT Detection
  28. GRB 251214B: COLIBRÍ observations of the afterglow
  29. EP251214a: EP-FXT non-detection and upper limit
  30. GRB 251214A: GECAM-B observation of a likely long burst
  31. GRB 251214B: 1.3m DFOT optical detection
  32. EP251214a: Global MASTER-Net observations report
  33. GRB 251214B: Xinglong-2.16m optical observation
  34. GRB 251214B : MASTER optical afterglow detection
  35. GRB 251214B: SVOM/C-GFT optical observations
  36. EP251214a: COLIBRÍ optical upper limit
  37. Swift GRB 251214B: Global MASTER-Net observations report
  38. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  39. Fermi GRB 251214A: Global MASTER-Net observations report
  40. EP251212a: Global MASTER-Net observations report
  41. EP251212a: KAIT optical upper limit
  42. EP251212a / GRB 251212A: AstroSat CZTI detection
  43. EP251212a: EP-FXT follow-up observation
  44. GRB 251211B: AstroSat CZTI detection
  45. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  46. GRB 251209A: NuSTAR detection of prompt emission
  47. EP251212a : COLIBRÍ optical upper limit
  48. EP251212a: Einstein Probe detection of an X-ray transient
  49. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  50. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  51. Fermi GRB 251211B: Global MASTER-Net observations report
  52. IceCube-251210A: DDOTI Optical Upper Limit
  53. GRB 251209A: Fermi GBM observation
  54. GRB 251205A: 1.3m DFOT optical upper limit
  55. GRB 251209A: AstroSat CZTI detection
  56. EP251124a: Mondy optical upper limit
  57. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  58. EP251130a: Mondy and AbAO optical observations
  59. GRB 251208A: AstroSat CZTI detection
  60. Fermi GBM Sub-Threshold Detection of GRB 251205A
  61. GRB 251208A: Glowbug gamma-ray detection
  62. GRB 251208B: COLIBRÍ optical upper limits
  63. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  64. GRB 251208C: GECAM-B observation of a short burst
  65. GRB 251208A: GECAM-B observation of a short burst
  66. Fermi GRB 251209A: Global MASTER-Net observations report
  67. Fermi GRB 251208C: Global MASTER-Net observations report
  68. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  69. GRB 251208B: Swift-XRT afterglow detection
  70. GRB 251208D: LAST optical upper limit
  71. GRB 251208D: LCO analysis of the XRT sources
  72. GRB 251208B: Fermi GBM Observation
  73. GRB 251208B: GROWTH-India Telescope optical upper limits
  74. GRB 251205A: J-band detection with WINTER
  75. GRB 251208D: Swift-XRT observations
  76. GRB 251208A: SVOM/GRM observation of a short burst
  77. GRB 251208C: SVOM/GRM observation of a short burst
  78. GRB 251129A: e-MERLIN C-band observations
  79. GRB 251205A: Liverpool Telescope further optical follow-up observations
  80. GRB 251208D: LCO optical upper limits
  81. GRB 251208B: Swift ToO observations
  82. GRB 251208B: Fermi-LAT detection
  83. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  84. GRB 251208D: SVOM possible detection of a faint burst
  85. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  86. GRB 251205A: FTW optical and NIR observations
  87. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  88. GRB 251205A: Liverpool Telescope further optical follow-up observations
  89. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
  90. GRB 251205A: ZTF and ATLAS optical afterglow detections
  91. GRB 251205A: GROWTH-India Telescope optical observations
  92. GRB 251205A: Swift-BAT refined analysis
  93. GRB 251205A: Swift/UVOT Detection
  94. GRB 251205A: Liverpool Telescope optical follow-up observations
  95. GRB 251203C: Swift/UVOT Upper Limit
  96. Konus-Wind detection of GRB 251118A
  97. GRB 251205A: Zeiss-1000 Koshka observatory optical observations
  98. GRB 251205A: COLIBRÍ optical observations
  99. GRB 251205A: GOTO optical afterglow detection
  100. GRB 251205A: NOT optical observations

Advanced

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