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"

23730 results found.

  1. GRB 231208A: GRBAlpha detection
  2. GRB231205B: Swift/UVOT Upper Limits
  3. GRB 231208A: Glowbug gamma-ray detection
  4. GRB 231205B: Swift-BAT refined analysis
  5. LIGO/Virgo/KAGRA S231206cc: Identification of a GW compact binary merger candidate
  6. LIGO/Virgo/KAGRA S231206ca: Identification of a GW compact binary merger candidate
  7. GRB 231205B: AGILE detection
  8. Fermi trigger No 723581802: Global MASTER-Net observations report
  9. GRB 231206B: Fermi GBM Final Real-time Localization
  10. GRB 231205B: Swift-XRT refined Analysis
  11. GRB 231205B: REM optical/NIR upper limits
  12. GRB 231129C: ASIM MXGS observation and localization
  13. GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
  14. GRB 231206A: GECAM-B detection of a short burst (correction)
  15. GRB 231205B : MITSuME Akeno optical upper limits
  16. GRB 231206A: GECAM-B detection of a short burst
  17. GRB 231205B: Gaoyazi/GOT optical upper limit
  18. GRB 231205B: Nanshan/HMT optical upper limit
  19. GRB 231205B: LCOGT Optical Upper Limits
  20. GRB 231205A: DDOTI Upper Limits on the Afterglow
  21. LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search
  22. GRB 231204A: Glowbug gamma-ray detection
  23. Swift GRB231205.70: Global MASTER-Net observations report
  24. GRB 231204A: CALET Gamma-Ray Burst Monitor detection
  25. GRB 231205B: Swift detection of a burst
  26. GRB 231205A: GECAM-B detection of a short burst
  27. Fermi trigger No 723435916: Global MASTER-Net observations report
  28. Fermi trigger No 723326169: Global MASTER-Net observations report
  29. Fermi trigger No 723412808: Global MASTER-Net observations report
  30. Konus-Wind detection of GRB 231129C
  31. Fermi trigger No 723279695: Global MASTER-Net observations report
  32. GRB 231129C: Swift-XRT afterglow detection
  33. Fermi trigger No 723149952: Global MASTER-Net observations report
  34. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  35. GRB 231129A: VZLUSAT-2 detection
  36. GRB 231128A: VZLUSAT-2 detection
  37. GRB 231129C: AGILE detection
  38. GRB 231129A : MITSuME Akeno optical upper limits
  39. GRB 231129A: Swift-BAT refined analysis
  40. GRB 231129C: MASTER OT detection
  41. GRB 231129A: BOOTES-5/JGT optical upper limit
  42. GRB 231129C: Fermi-LAT detection
  43. GRB 231129C: GRBAlpha detection
  44. GRB 231129C: Glowbug gamma-ray detection
  45. GRB 231129C: Swift-XRT observations
  46. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  47. GRB 231129C: Fermi GBM Observation of a very bright GRB
  48. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  49. GRB 231127A: GRBAlpha detection
  50. GRB 231129C: MAXI/GSC detection
  51. GRB 231129A: Enhanced Swift-XRT position
  52. Fermi trigger No 722977823: Global MASTER-Net observations report
  53. GRB 231129B: MAXI/GSC detection
  54. Integral GRB231129.21: Global MASTER-Net observations report
  55. GRB 231129A: GECAM-C detection of a long burst
  56. GRB 231129A: Swift detection of a burst
  57. LIGO/Virgo/KAGRA S231127cg: Identification of a GW compact binary merger candidate
  58. GRB 231127A: CALET Gamma-Ray Burst Monitor detection
  59. GRB 231125A: GRBAlpha detection
  60. GRB 231125A: CALET Gamma-Ray Burst Monitor detection
  61. GRB 231125A (short): Glowbug gamma-ray detection
  62. GRB 231124A: GRBAlpha detection
  63. Fermi trigger No 722653947: Global MASTER-Net observations report
  64. Fermi trigger No 722460326: Global MASTER-Net observations report
  65. Fermi trigger No 722507896: Global MASTER-Net observations report
  66. GRB 231123C (short): Glowbug gamma-ray detection
  67. GRB 231124A: Glowbug gamma-ray detection
  68. Fermi trigger No 722462310: Global MASTER-Net observations report
  69. GRB 231124A: CALET Gamma-Ray Burst Monitor detection
  70. GRB 231115A: XMM-Newton observation
  71. GRB 231123A: AstroSat CZTI detection
  72. Fermi trigger No 722400249: Global MASTER-Net observations report
  73. GRB 231118A: REM optical afterglow detection
  74. GRB 231122B: AstroSat CZTI detection
  75. GRB 231122B: CALET Gamma-Ray Burst Monitor detection
  76. GRB 231122B: Glowbug gamma-ray detection
  77. GRB 231117A: Continued GTC Observations
  78. Fermi trigger No 722349867: Global MASTER-Net observations report
  79. GRB 231122A: GECAM detection
  80. GRB 231122B: GECAM detection
  81. GRB 231117A: GTC Near-Infrared Observations
  82. GRB 231117A: Swift-BAT refined analysis
  83. GRB 231118A: GRBAlpha detection
  84. GRB 231118A: VZLUSAT-2 detection
  85. GRB 231118A: Swift-BAT refined analysis
  86. Konus-Wind detection of GRB 231020A
  87. GRB 231117A: LDT Confirmation of Optical Fading
  88. GRB 231118B: CALET Gamma-Ray Burst Monitor detection
  89. GRB 231117A: CALET Gamma-Ray Burst Monitor detection
  90. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  91. GRB 231118B: Fermi GBM observation
  92. GRB 231118A: Fermi GBM observation
  93. LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
  94. GRB 231118A: MeerLICHT afterglow detection
  95. LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches
  96. Fermi trigger No 722039659: Global MASTER-Net observations report
  97. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  98. LIGO/Virgo/KAGRA S231119u: Identification of a GW compact binary merger candidate
  99. GRB 231117A: MAAO 0.7-m telescope optical upper limit
  100. GRB 231117A: AKO Follow-Up Observation

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