Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

28261 results found.

  1. Fermi GRB 260129A: Global MASTER-Net observations report
  2. GRB 260128B: LCO optical upper limits
  3. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  4. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  5. GRB 260127A: Swift-BAT refined analysis
  6. GRB 260127B: Swift-XRT observations
  7. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  8. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  9. EP260128a: NOT optical counterpart candidate
  10. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  11. EP260128a: Liverpool Telescope optical observations and possible counterpart
  12. EP260128a: LCO optical upper limits
  13. EP260128a: Global MASTER-Net observations report
  14. EP260128a: Einstein Probe detection of an X-ray transient
  15. Fermi GRB 260127A: Global MASTER-Net observations report
  16. GRB 260127A: Fermi GBM Observation
  17. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  18. GRB 260127A: COLIBRÍ optical observations
  19. EP260126a: Seimei/TriCCS optical upper limit
  20. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  21. GRB 260127A: Swift-XRT refined Analysis
  22. GRB 260127A: SVOM/C-GFT optical observations
  23. GRB 260127A: Enhanced Swift-XRT position
  24. Fermi GRB 260127B: Global MASTER-Net observations report
  25. Swift GRB 260127A: Global MASTER-Net observations report
  26. GRB 260127A: LCO optical afterglow discovery
  27. GRB 260127A: Swift detection of a burst
  28. GRB 260125A: Swift-XRT observations
  29. EP260126a: Optical upper limit with Kinder observations
  30. EP260126a: Liverpool Telescope optical upper limits
  31. EP260126a: Further NOT optical upper limits
  32. EP260126a: COLIBRÍ optical upper limits
  33. EP260126a: NOT optical observations
  34. EP260126a: Einstein Probe detection of a fast X-ray transient
  35. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  36. GRB 251222A: SVOM/ECLAIRs refined analysis
  37. GRB 260125A: GOTO candidate optical counterpart
  38. Fermi GRB 260125B: Global MASTER-Net observations report
  39. GRB 260114A: SVOM/VT optical upper limits
  40. GRB 260122B: Swift-BAT refined analysis
  41. GRB 260120B: SVOM/GRM observation
  42. Swift GRB260122.97: Global MASTER-Net observations report
  43. EP260119a: Assy AZT-20 optical observations
  44. EP260119a: Mondy and SAO RAS optical upper limits
  45. EP260119a: Xinglong optical upper limit
  46. Fermi GRB 260120C: Global MASTER-Net observations report
  47. GRB 260120B: Swift-BAT refined analysis
  48. GRB 260120B: Swift-XRT refined Analysis
  49. EP260116a: COLIBRÍ further observations
  50. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  51. GRB 260120B: Fermi GBM Observation
  52. EP260105a: GTC/HiPERCAM optical observations
  53. GRB 260120B: Swift/UVOT Detection
  54. GRB 260120B: COLIBRÍ optical upper limits
  55. SVOM GRB260121.06: Global MASTER-Net observations report
  56. GRB 260120B: Enhanced Swift-XRT position
  57. GRB 260120B: SVOM/C-GFT optical counterpart detection
  58. GRB 260101A: 239Alferov CubeSat detection
  59. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  60. GRB 260120B: Swift detection of a burst
  61. Swift GRB260120B: Global MASTER-Net observations report
  62. EP260119A: Mondy I-Band Observations
  63. Fermi trigger No 790601190: Global MASTER-Net observations report
  64. Fermi trigger No 790570272: Global MASTER-Net observations report
  65. GRB 260114A: Swift/UVOT Upper Limits
  66. EP260119a: Liverpool Telescope optical follow-up observations
  67. GRB 251202A: further radio observations with the VLA
  68. EP260119a: KAIT optical observations
  69. EP260119a: SVOM/VT optical observation
  70. EP260119a: NOT optical observations
  71. EP260119a: SAO RAS optical observations
  72. SVOM GRB260119.92: Global MASTER-Net observations report
  73. SVOM GRB260119.92: Global MASTER-Net observations report
  74. SVOM GRB260119.90: Global MASTER-Net observations report
  75. EP260116a: COLIBRÍ detection of a fading optical source
  76. GRB 260117A: Swift-XRT afterglow detection
  77. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  78. EP260119a: Global MASTER-Net observations report
  79. EP260119a: LCO optical observations
  80. GRB 260117A: ZTSh optical upper limit
  81. EP260119a: COLIBRÍ optical counterpart candidate
  82. EP260119a: EP-WXT detection of a fast X-ray transient
  83. Swift GRB260118.48: Global MASTER-Net observations report
  84. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  85. SVOM GRB260117.82: Global MASTER-Net observations report
  86. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  87. Swift trigger on the HMXB 1A 1118-61
  88. GRB 260117A: SVOM/VT optical candidate
  89. GRB 260117A: SVOM/C-GFT upper limit
  90. GRB 260117A: Swift-XRT observations
  91. GRB 260117A: SVOM detection of a long faint burst
  92. EP 260116a: COLIBRÍ optical upper limit
  93. Swift triggered on the HMXB 1A 1118-61
  94. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  95. EP260116a: Liverpool Telescope upper limits
  96. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  97. EP260116A: 1.3m DFOT optical upper limit
  98. GRB 260114A: VLT/MUSE spectroscopic observations
  99. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  100. EP260116a: Global MASTER-Net observations report

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