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"

45774 results found.

  1. GRB 251023C: AstroSat CZTI detection
  2. EP251023b/GRB 251023B: JinShan optical observation
  3. GRB 251022A: Swift-XRT detection of GOTO25iym
  4. EP251023b: Global MASTER-Net observations report
  5. EP251023b/GRB 251023B : Einstein Probe detection of a fast X-ray transient
  6. GRB 251023C: CALET Gamma-Ray Burst Monitor detection
  7. GRB 251022A: GROWTH-India Telescope optical observations
  8. GRB 251023C: Swift/BAT-GUANO localization skymap of a burst
  9. EP251023a: GROWTH-India Telescope optical observations
  10. GRB 251022A: Fermi GBM Observation
  11. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  12. GRB 251023A: Glowbug gamma-ray detection
  13. GRB 251023B: Glowbug gamma-ray detection
  14. EP251023a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm telescope at Teide Observatory
  15. EP251023a: Global MASTER-Net observations report
  16. GRB 251023B / EP#01709247298: COLIBRÍ optical counterpart candidate
  17. IPN triangulation of GRB 251016B
  18. GRB 251023B: CALET Gamma-Ray Burst Monitor detection
  19. EP#01709247298: Swift-XRT counterpart detection
  20. EP251023a: COLIBRÍ optical observations
  21. GRB 251013C: further SAO RAS optical observations
  22. EP251023a: Keck/LRIS spectroscopic redshift z=2.232
  23. GRB 251022A: COLIBRÍ optical observations
  24. GRB 251013C: ISON-Castelgrande observatory optical observations
  25. GRB 251022A: MASTER OT detection
  26. GRB 251022A: DDOTI Optical Detection
  27. EP251021b/GRB 251021A: SVOM/VT optical candidate
  28. GRB 251023B / MAXI J0451+122: MAXI/GSC detection
  29. EP251023a: NOT optical counterpart detection
  30. Fermi GRB 251023A: Global MASTER-Net observations report
  31. EP251023a: GSP Optical Counterpart Detection
  32. EP251023a: Einstein Probe detection of an X-ray transient
  33. EP/WXT 01709247295: GOTO optical afterglow candidate.
  34. GRB 251022A: GOTO optical counterpart detection
  35. GRB 251023A: Fermi GBM Final Localization Correction
  36. GRB 251022A: Fermi-LAT detection
  37. GRB 251016B: Fermi GBM Detection
  38. GRB 251022A: Tiled Swift observations
  39. LAT GRB251022A: Global MASTER-Net observations report
  40. GRB 251022A: Fermi GBM Final Real-time Localization
  41. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  42. EP251021b: BOOTES-7 optical upper limit
  43. EP251021b: Einstein Probe detection of a fast X-ray transient
  44. GRB 250911A: MAXI/GSC detection
  45. LIGO/Virgo/KAGRA S251021u: Updated Sky localization
  46. GRB 251016A: SVOM/ECLAIRs refined analysis
  47. LIGO/Virgo/KAGRA S251021u: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S251018bi: Updated Sky localization
  49. Fermi-LAT gamma-ray observations of IceCube-251018A
  50. GRB 251017A : RAPAS follow-up observations
  51. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  52. GRB 251017A: COLIBRÍ optical observations of a late plateau
  53. IceCube-251018A: DDOTI Optical Upper Limit
  54. GRB 251017A: Swift-BAT refined analysis
  55. GRB 251016A: Fermi GBM Observation
  56. GRB 251018A: Fermi GBM Observation
  57. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  58. GRB 251018A: Swift-XRT refined Analysis
  59. GRB 251018A: Enhanced Swift-XRT position
  60. Fermi trigger No 782500909: Global MASTER-Net observations report
  61. GRB 251016A: HXMT/HE detection
  62. IceCube-251018A: Global MASTER-Net observations report
  63. LIGO/Virgo/KAGRA S251018bi: Identification of a GW compact binary merger candidate
  64. GRB 251016A: Swift-XRT afterglow detection
  65. GRB 251017A: Swift/UVOT Detection
  66. GRB 251016A: Swift/UVOT Detection
  67. GRB 251018A: Swift/UVOT Detection
  68. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  69. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  70. GRB 251017A: VLT/MUSE spectroscopic redshift z = 4.327
  71. GRB 251016A: VLT/FORS2 Optical Observation
  72. GRB 251017A: COLIBRÍ photometric redshift
  73. GRB 251017A: Swift-XRT refined Analysis
  74. GRB 251018A: MASTER OT detection
  75. GRB 251018A: TRT optical afterglow detection
  76. Swift GRB 251018A: Global MASTER-Net observations report
  77. GRB 251018A: Swift detection of a burst with an optical counterpart
  78. GRB 251018A: Fermi GBM Final Real-time Localization
  79. GRB 251017A: SVOM/VT optical observation
  80. GRB 251011A: Fermi GBM Observation
  81. GRB 251017A: OHP/T193 i-band observations
  82. GRB 251013C: OHP/T193 third epoch optical observations and detected rebrightening
  83. LIGO/Virgo/KAGRA S251017di: Retraction of GW compact binary merger candidate
  84. GRB 251017A: J-band detection with WINTER
  85. GRB 251017A: Glowbug gamma-ray detection
  86. GRB 251013C: Liverpool Telescope observations
  87. GRB 251013C: Leavitt Observatory optical photometry
  88. Fermi GRB 251016B: Global MASTER-Net observations report
  89. GRB 251017A: JinShan observations of the optical afterglow
  90. Swift GRB 251017A: Global MASTER-Net observations report
  91. GRB 251017A : MITSuME Akeno optical afterglow candidate detection
  92. Swift Trigger 1404295 is not a GRB
  93. GRB 251016A: AstroSat CZTI detection of a short burst
  94. GRB 251017A: Enhanced Swift-XRT position
  95. GRB 251017A: COLIBRÍ Early Afterglow Detection
  96. GRB 251016B: AstroSat CZTI detection
  97. GRB 251017A: BOOTES-5/JGT early optical afterglow detection
  98. GRB 251017A: Swift detection of a burst with an optical counterpart
  99. GRB 251016A: CALET Gamma-Ray Burst Monitor detection
  100. GRB 251016B: CALET Gamma-Ray Burst Monitor 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