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"

26507 results found.

  1. Swift trigger on the HMXB 1A 1118-61
  2. GRB 260117A: SVOM/C-GFT upper limit
  3. GRB 260117A: Swift-XRT observations
  4. GRB 260117A: SVOM detection of a long faint burst
  5. EP 260116a: COLIBRÍ optical upper limit
  6. Swift triggered on the HMXB 1A 1118-61
  7. GRB 260115A: GECAM-B observation
  8. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  9. EP260116a: Liverpool Telescope upper limits
  10. EP260116A: 1.3m DFOT optical upper limit
  11. GRB 260114A: VLT/MUSE spectroscopic observations
  12. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  13. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  14. EP260116a: Xinglong optical upper limit
  15. EP260116a: Einstein Probe detection of an X-ray transient
  16. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  17. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  18. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  19. GRB 251222A: radio detection with the VLA
  20. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  21. Konus-Wind detection of GRB 260114A
  22. GRB 260114A: Swift-XRT refined Analysis
  23. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  24. GRB 260114A : MITSuME Akeno optical upper limits
  25. GRB 260114A: COLIBRÍ optical upper limits
  26. GRB 260114A: TNG NIR upper limit
  27. GRB 260114A: NOT optical observations
  28. Konus-Wind detection of GRB 251230A / EP251230a
  29. GRB 260114A: SVOM/GRM observation of a short burst
  30. GRB 260114A: GECAM-B observation of a short burst
  31. GRB 260114A: Mondy optical observations
  32. GRB 260114A: Fermi GBM observation
  33. GRB 260114A: GMG Optical Observation
  34. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  35. GRB 260114A: Swift detection of a short burst
  36. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  37. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  38. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  39. EP260110a: TRT optical upper limits
  40. Konus-Wind detection of GRB 260101A
  41. GRB 260111A: Swift-XRT observations
  42. Swift Trigger 1439093: is probably not GRB 260113A
  43. GRB 260111A: COLIBRÍ optical afterglow candidate
  44. GRB 260111A: Fermi GBM Observation
  45. The EP-WXT trigger 01709251266 is likely a flaring star
  46. GRB 251230A: Mondy Optical Observations
  47. Swift trigger 1436759 is not an astrophysical event
  48. EP260110a: KAIT optical upper limit
  49. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  50. EP 260110a: COLIBRÍ optical observations
  51. EP260110a: SVOM/C-GFT upper limit
  52. EP260110a: Einstein Probe detection of an X-ray transient
  53. GRB 260109C: LCO optical upper limits
  54. GRB 260109C: Kilonova-Catcher optical upper limit
  55. Swift Trigger 1434591: possible GRB 260109C
  56. GRB 260102A: Swift-XRT afterglow detection
  57. GRB 260102A: AbAO optical observations
  58. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  59. The EP-WXT trigger 01709251112 is likely a flaring star
  60. GRB 260105B: Fermi GBM Detection
  61. GRB 260105A: SVOM/GRM observation
  62. GRB 260105B: SVOM/GRM observation
  63. The EP-WXT trigger 01709251028 is likely a flaring star
  64. FRB 20251229A: COLIBRÍ optical upper limits
  65. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  66. EP260105a: LCO Optical Upper limit
  67. EP260104a: Einstein Probe detection of a fast X-ray transient
  68. GRB 260101A: COLIBRÍ optical upper limits
  69. EP260105a: Einstein Probe detection of an X-ray transient
  70. GRB 260104A: COLIBRÍ optical upper limits
  71. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  72. GRB 260104A: Swift-XRT refined Analysis
  73. GRB 260104A: Enhanced Swift-XRT position
  74. GRB 260101A: Swift/UVOT Detection
  75. GRB 260104A: Swift detection of a burst
  76. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  77. GRB 260101A: COLIBRÍ optical observations
  78. GRB 260102B: Fermi GBM Final Real-time Localization
  79. GRB 260102A: LCO optical upper limits
  80. GRB 260102A: Swift-XRT observations
  81. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  82. GRB 260102A: SVOM/VT optical counterpart
  83. GRB 260101A: Fermi GBM Observation
  84. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  85. GRB 260102A: SVOM detection of a burst
  86. GRB 260101A: SVOM/GRM observation
  87. GRB 260101A: Swift-XRT refined Analysis
  88. GRB 260101A: Enhanced Swift-XRT position
  89. EP260101a: Einstein Probe detection of an X-ray transient
  90. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  91. GRB 260101A: LCO detection of the optical counterpart
  92. GRB 260101A: Swift detection of a burst with an optical counterpart
  93. GRB 251230A: GRANDMA/TAROT Early Detection
  94. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  95. EP251229a: Optical upper limit with Kinder observations
  96. GRB 251230A: 1.3m DFOT optical upper limit
  97. GRB 251230A: Swift-XRT refined Analysis
  98. GRB 251222A: Mondy Optical Observations
  99. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  100. GRB 251230A: Swift/UVOT detection

Advanced

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