Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. 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"

27018 results found.

  1. The EP-WXT trigger 01709318279 is likely a flaring star
  2. GRB 260918A: SVOM/VT optical upper limits
  3. GRB 260916B: Glowbug gamma-ray detection of a short burst
  4. GRB 260918A: EP-FXT follow-up observation
  5. GRB 260917B: Mondy optical upper limit
  6. IPN triangulation of GRB 260916B (short)
  7. EP260917b: EP-WXT detection of an X-ray transient
  8. EP260917A: J-band upper limit with WINTER
  9. IPN triangulation of GRB 260810A
  10. GRB 260917B: EP-FXT follow-up observation
  11. GRB 260915A: Swift-XRT afterglow detection
  12. GRB 260918A: LCO optical upper limits
  13. EP260917a: Einstein Probe detection of an X-ray transient
  14. GRB 260918A: SVOM detection of a burst
  15. GRB 260917C: Fermi GBM Final Real-time Localization
  16. GRB 260916B: Fermi GBM Detection
  17. GRB 260916B: Fermi GBM Final Localization
  18. GRB 260917A: Glowbug gamma-ray detection
  19. GRB 260915A: SVOM/ECLAIRs refined analysis
  20. GRB 260917B: WINTER J-band observations
  21. GRB 260917B: SVOM/VT optical observations
  22. GRB 260917B: LCO optical observation
  23. GRB 260917B: SVOM detection of a faint burst
  24. GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
  25. GRB 260917A: Fermi GBM Final Real-time Localization
  26. The EP-WXT trigger 01709317235 is likely a flaring star
  27. GRB 260915A: J-band upper limit with WINTER
  28. IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
  29. GRB 260909A: NOEMA detection
  30. GRB 260914A: SVOM/GRM observation
  31. GRB 260914A: Mondy and TShAO optical observations
  32. GRB 260914A: SVOM/ECLAIRs refined analysis
  33. GRB 260909A: Swift-XRT observations
  34. GRB 260916A: MAXI/GSC detection
  35. GRB 260915A: Swift ToO observations
  36. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  37. GRB 260915A: SVOM/C-GFT optical upper limits
  38. GRB 260915A: EP-FXT follow-up observation
  39. GRB 260915A: SVOM/VT refined early optical upper limits
  40. GRB 260915A: REM optical/NIR observations
  41. GRB 260914A: REM optical/NIR observations
  42. GRB 260915A: SVOM/VT optical upper limits
  43. GRB 260914A: VLT/X-shooter spectroscopic redshift z = 0.778
  44. GRB 260915A: 10.4m GTC deep optical limits
  45. GRB 260915A: NOT optical upper limit
  46. GRB 260915A: SVOM/VT optical upper limits from VHF data
  47. Fermi GBM Sub-Threshold Detection of GRB 260915A
  48. GRB 260915A: LCO optical upper limits
  49. GRB 260914A: EP-FXT follow-up observation
  50. GRB 260915A: SVOM detection of a burst
  51. Fermi GBM Sub-Threshold Detection of GRB 260914A
  52. GRB 260914A: LCO optical observation
  53. GRB 260914A: SVOM/C-GFT optical observations
  54. GRB 260914A: SVOM/VT optical counterpart confirmation
  55. GRB 260914A: SVOM/VT optical observation from VHF data
  56. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  57. GRB 260914A: SVOM detection of a burst
  58. GRB 260818A: Continued ATCA observations
  59. GRB 260913A: SVOM/C-GFT optical upper limit
  60. GRB 260913A: SVOM detection of a faint burst
  61. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  62. GRB 260907A: SVOM/GRM observation
  63. GRB 260909A: SVOM/ECLAIRs refined analysis
  64. GRB 260910B: GOTO tentative optical counterpart candidates
  65. GRB 260909A: Swift ToO observations
  66. GRB 260910B: Fermi GBM Final Real-time Localization
  67. GRB 260909A: KAIT optical upper limit
  68. GRB 260903A: Swift-XRT observations
  69. EP260806a: VLA+ALMA radio detections
  70. GRB 260909A: OHP/T193 z-band upper limit
  71. GRB 260909A: EP-FXT follow-up observation
  72. GRB 260910A: Fermi GBM Final Real-time Localization
  73. EP260623a: NOEMA detections
  74. GRB 260909A: SVOM/VT optical upper limits
  75. GRB 260909A: SVOM/GRM observation
  76. GRB 260909A: Xinglong 2.16m optical upper limit
  77. GRB 260909A: SVOM/C-GFT optical upper limit
  78. GRB 260909A: SVOM detection of a burst
  79. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  80. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  81. GRB 260903A: Swift ToO observations
  82. The EP-WXT trigger 01709305715 is likely a flaring star
  83. GRB 260907B: Fermi GBM Final Real-time Localization
  84. GRB 260907A: Fermi GBM Final Real-time Localization
  85. EP260903a: EP-FXT follow-up observation
  86. The EP-WXT trigger 01709302592 is likely a flaring star
  87. GRB 260903A: J-band upper limit with WINTER
  88. GRB 260903A: SVOM/ECLAIRs refined analysis
  89. GRB 260903A: SAO RAS optical observations
  90. GRB 260830A: GECAM-B detection of a burst
  91. EP260903a: EP-WXT detection of a fast X-ray transient
  92. GRB 260830A: Insight-HXMT/HE detection
  93. GRB 260903A: EP-FXT follow-up observation
  94. GRB 260903A: NOT optical observations and afterglow fading
  95. NuSTAR Transient 260828: SOAR Optical Upper Limits
  96. GRB 260903A: LCO optical observations
  97. GRB 260903A: SVOM/VT optical candidate
  98. GRB 260831A: GECAM-B observation
  99. GRB 260903A: LCO optical counterpart detection
  100. GRB 260827A: Insight-HXMT/HE detection

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