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"

28042 results found.

  1. GRB 260127A: SVOM/C-GFT optical observations
  2. GRB 260127A: Enhanced Swift-XRT position
  3. Fermi GRB 260127B: Global MASTER-Net observations report
  4. Swift GRB 260127A: Global MASTER-Net observations report
  5. GRB 260127A: LCO optical afterglow discovery
  6. GRB 260127A: Swift detection of a burst
  7. GRB 260125A: Swift-XRT observations
  8. EP260126a: Optical upper limit with Kinder observations
  9. EP260126a: Liverpool Telescope optical upper limits
  10. EP260126a: Further NOT optical upper limits
  11. EP260126a: COLIBRÍ optical upper limits
  12. EP260126a: NOT optical observations
  13. EP260126a: Einstein Probe detection of a fast X-ray transient
  14. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  15. GRB 251222A: SVOM/ECLAIRs refined analysis
  16. GRB 260125A: GOTO candidate optical counterpart
  17. Fermi GRB 260125B: Global MASTER-Net observations report
  18. GRB 260114A: SVOM/VT optical upper limits
  19. GRB 260122B: Swift-BAT refined analysis
  20. GRB 260120B: SVOM/GRM observation
  21. Swift GRB260122.97: Global MASTER-Net observations report
  22. EP260119a: Assy AZT-20 optical observations
  23. EP260119a: Mondy and SAO RAS optical upper limits
  24. EP260119a: Xinglong optical upper limit
  25. Fermi GRB 260120C: Global MASTER-Net observations report
  26. GRB 260120B: Swift-BAT refined analysis
  27. GRB 260120B: Swift-XRT refined Analysis
  28. EP260116a: COLIBRÍ further observations
  29. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  30. GRB 260120B: Fermi GBM Observation
  31. EP260105a: GTC/HiPERCAM optical observations
  32. GRB 260120B: Swift/UVOT Detection
  33. GRB 260120B: COLIBRÍ optical upper limits
  34. SVOM GRB260121.06: Global MASTER-Net observations report
  35. GRB 260120B: Enhanced Swift-XRT position
  36. GRB 260120B: SVOM/C-GFT optical counterpart detection
  37. GRB 260101A: 239Alferov CubeSat detection
  38. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  39. GRB 260120B: Swift detection of a burst
  40. Swift GRB260120B: Global MASTER-Net observations report
  41. EP260119A: Mondy I-Band Observations
  42. Fermi trigger No 790601190: Global MASTER-Net observations report
  43. Fermi trigger No 790570272: Global MASTER-Net observations report
  44. GRB 260114A: Swift/UVOT Upper Limits
  45. EP260119a: Liverpool Telescope optical follow-up observations
  46. GRB 251202A: further radio observations with the VLA
  47. EP260119a: KAIT optical observations
  48. EP260119a: SVOM/VT optical observation
  49. EP260119a: NOT optical observations
  50. EP260119a: SAO RAS optical observations
  51. SVOM GRB260119.92: Global MASTER-Net observations report
  52. SVOM GRB260119.92: Global MASTER-Net observations report
  53. SVOM GRB260119.90: Global MASTER-Net observations report
  54. EP260116a: COLIBRÍ detection of a fading optical source
  55. GRB 260117A: Swift-XRT afterglow detection
  56. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  57. EP260119a: Global MASTER-Net observations report
  58. EP260119a: LCO optical observations
  59. GRB 260117A: ZTSh optical upper limit
  60. EP260119a: COLIBRÍ optical counterpart candidate
  61. EP260119a: EP-WXT detection of a fast X-ray transient
  62. Swift GRB260118.48: Global MASTER-Net observations report
  63. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  64. SVOM GRB260117.82: Global MASTER-Net observations report
  65. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  66. Swift trigger on the HMXB 1A 1118-61
  67. GRB 260117A: SVOM/VT optical candidate
  68. GRB 260117A: SVOM/C-GFT upper limit
  69. GRB 260117A: Swift-XRT observations
  70. GRB 260117A: SVOM detection of a long faint burst
  71. EP 260116a: COLIBRÍ optical upper limit
  72. Swift triggered on the HMXB 1A 1118-61
  73. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  74. EP260116a: Liverpool Telescope upper limits
  75. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  76. EP260116A: 1.3m DFOT optical upper limit
  77. GRB 260114A: VLT/MUSE spectroscopic observations
  78. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  79. EP260116a: Global MASTER-Net observations report
  80. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  81. EP260116a: Xinglong optical upper limit
  82. EP260116a: Einstein Probe detection of an X-ray transient
  83. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  84. IceCube Alert 260115.73: Global MASTER-Net observations report
  85. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  86. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  87. Fermi GRB 260115A: Global MASTER-Net observations report
  88. GRB 251222A: radio detection with the VLA
  89. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  90. GRB 260114A: Swift-XRT refined Analysis
  91. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  92. GRB 260114A : MITSuME Akeno optical upper limits
  93. GRB 260114A: COLIBRÍ optical upper limits
  94. GRB 260114A: TNG NIR upper limit
  95. GRB 260114A: NOT optical observations
  96. GRB 260114A: SVOM/GRM observation of a short burst
  97. Swift GRB 260114A: Global MASTER-Net observations report
  98. GRB 260114A: Mondy optical observations
  99. GRB 260114A: GMG Optical Observation
  100. Fermi-LAT Gamma-ray Observations of IceCube-260111A

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov