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"

11532 results found.

  1. GRB 241030A: Fermi-LAT detection
  2. GRB 240912A: radio detection with the VLA
  3. Fermi GRB 241030A: Global MASTER-Net observations report
  4. GRB 241030A: AKO Optical Afterglow Detection
  5. GRB 241030A: Swift/UVOT Detection
  6. GRB 241030A: SVOM/GRM observation
  7. GRB 241026A: Swift-BAT refined analysis
  8. GRB 241030A: SVOM/C-GFT optical observations
  9. GRB 241026A: LBT optical observations
  10. GRB 241030A: Multiband optical detection with Mephisto
  11. GRB 241030A: SVOM/VT optical afterglow observations
  12. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  13. GRB 241030A : MITSuME Akeno optical afterglow detection
  14. GRB 241029A: GROWTH-India Telescope optical follow up
  15. GRB 241030A: TRT optical observations
  16. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  17. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  18. GRB 241030A: Fermi GBM Final Real-time Localization
  19. GRB 241029A: SAO RAS optical observations
  20. GRB 241026A: SAO RAS optical observations
  21. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  22. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  23. GRB 241026A: Swift/UVOT Upper Limits
  24. GRB 241029A: Fermi GBM Observation
  25. GRB 241029A: AKO Optical Afterglow Detection
  26. GRB 241029A: GOTO optical afterglow detection
  27. GRB 241029A: MASTER early optical counterpart detection
  28. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  29. GRB 241029A: Mephisto observations
  30. GRB 241029A: TRT optical afterglow candidate detection
  31. GRB 241029A: SVOM/GRM observation
  32. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  33. Fermi trigger No 751861204: Global MASTER-Net observations report
  34. GRB 241029A: Fermi GBM Final Real-time Localization
  35. GRB 241026A: the 100th GRB detected by GRBAlpha
  36. GRB 241026A: TNOT optical counterpart detection
  37. Konus-Wind detection of GRB 241025A
  38. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  39. GRB 241026A: LBT redshift confirmation
  40. GRB 241026A: GECAM detection
  41. GRB 241025A: further SAO RAS optical observations
  42. GRB 241026A: BTA and Zeiss-1000 optical observations
  43. GRB 241026A: SVOM/GRM observation
  44. GRB 241026A: GROWTH-India Telescope optical observations
  45. GRB 241026A Fermi GBM Analysis
  46. GRB 241026A: BTA redshift identification of z = 2.79
  47. GRB 241026A: J-band observations with WINTER
  48. GRB 241026A: Las Cumbres optical detection
  49. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  50. GRB 241026A: Swift-XRT refined Analysis
  51. GRB 241026A: Enhanced Swift-XRT position
  52. GRB 241026A: KAIT optical observations
  53. Fermi trigger No 751616906: Global MASTER-Net observations report
  54. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  55. GRB 241026A: SAO RAS observations of possible optical afterglow
  56. Fermi GRB 241026A: Global MASTER-Net observations report
  57. GRB 241026A: Prompt enhanced Swift-XRT position
  58. GRB 241026A: Swift detection of a burst
  59. GRB 241026A: Fermi GBM Final Real-time Localization
  60. ​GRB 241025A: optical photometry from Konkoly
  61. GRB 241025A: GROWTH-India Telescope optical observations
  62. GRB 241025A: COLIBRÍ Detection of the Afterglow
  63. GRB 241025C: Fermi GBM Detection
  64. GRB 241025A: Fermi GBM Observation
  65. GRB 241025C: Fermi GBM Final Localization
  66. GRB 241025B: Fermi GBM Final Localization
  67. Fermi trigger No 751563375: Global MASTER-Net observations report
  68. Fermi trigger No 751554401: Global MASTER-Net observations report
  69. Fermi GRB 241025A: Global MASTER-Net observations report
  70. EP241025a (GRB 241025A): EP observations update
  71. GRB 241025A : SVOM/VT optical afterglow observations
  72. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  73. GRB 241025A: DDOTI Afterglow detection
  74. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  75. GRB 241025A: SVOM/GRM observation
  76. GRB 241025A: TRT optical afterglow observation
  77. Fermi GRB 241024B: Global MASTER-Net observations report
  78. GRB 241025A: Fermi GBM Final Real-time Localization
  79. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  80. GRB 241024B: Fermi GBM Final Localization
  81. EP241021a: No Detection in Fermi-GBM Observation
  82. GRB 241024A: Fermi GBM Final Localisation
  83. Fermi trigger No 751449953: Global MASTER-Net observations report
  84. GRB 241018A: REM optical/NIR upper limits
  85. GRB 241016B: Fermi GBM Observations
  86. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  87. Fermi trigger No 750788395: Global MASTER-Net observations report
  88. GRB 241016B: SVOM/GRM observation
  89. GRB241016C: Fermi GBM Final Localization
  90. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  91. Fermi GRB 241016B: Global MASTER-Net observations report
  92. GRB 241016B: Fermi GBM Final Localization
  93. Fermi GRB 241016A: Global MASTER-Net observations report
  94. GRB 241016A: Fermi GBM Final Real-time Localization
  95. GRB 241013B: Fermi GBM Observation
  96. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  97. GRB 241013A: Fermi GBM Observation
  98. GRB 240916A: radio detection with the VLA
  99. GRB241013A: REM observations
  100. GRB 241013B: SVOM/GRM 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