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"

32725 results found.

  1. GRB 241029A: GOTO optical afterglow detection
  2. EP241021a: continued SOAR observations confirm optical rebrightening
  3. GRB 241029A: MASTER early optical counterpart detection
  4. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  5. GRB 241029A: Mephisto observations
  6. EP 241026b: LBT possible optical counterpart (brightening source)
  7. GRB 241029A: TRT optical afterglow candidate detection
  8. GRB 241029A: Swift ToO observations
  9. GRB 241029A: SVOM/GRM observation
  10. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  11. GRB 240821A: Keck/LRIS spectroscopic observations
  12. EP241021a: Gemini-South detection of optical rebrightening
  13. GRB 241026A: the 100th GRB detected by GRBAlpha
  14. GRB 241026A: TNOT optical counterpart detection
  15. Konus-Wind detection of GRB 241025A
  16. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  17. GRB 241026A: LBT redshift confirmation
  18. GRB 241026A: GECAM detection
  19. GRB 241025A: further SAO RAS optical observations
  20. GRB 241026A: BTA and Zeiss-1000 optical observations
  21. GRB 241026A: SVOM/GRM observation
  22. EP241026B: GROWTH-India Telescope optical upper limit
  23. GRB 241025A: Swift/UVOT Detection
  24. GRB 241026A: GROWTH-India Telescope optical observations
  25. GRB 241026A Fermi GBM Analysis
  26. GRB 241026A: BTA redshift identification of z = 2.79
  27. GRB 241026A: J-band observations with WINTER
  28. GRB 241025A: SAO RAS optical observations
  29. GRB 241026A: Las Cumbres optical detection
  30. GRB 241025A: Mondy optical observations
  31. EP241021a: SOAR observations of the optical counterpart
  32. EP241021a: further SAO RAS optical observations
  33. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  34. EP 241026b: LBT optical observations
  35. EP241021a: e-MERLIN radio observation
  36. EP EP241026b: Global MASTER-Net observations report
  37. GRB 241026A: KAIT optical observations
  38. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  39. GRB 241026A: SAO RAS observations of possible optical afterglow
  40. Fermi GRB 241026A: Global MASTER-Net observations report
  41. GRB241025A: 1.3m DFOT optical afterglow detection
  42. EP241021a: optical follow-up observations with Xinglong Observatory
  43. ​GRB 241025A: optical photometry from Konkoly
  44. GRB 241025A: GROWTH-India Telescope optical observations
  45. GRB 241025A: COLIBRÍ Detection of the Afterglow
  46. GRB 241025C: Fermi GBM Detection
  47. GRB 241025A: Fermi GBM Observation
  48. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  49. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  50. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  51. EP 241021a: Swift-XRT observations
  52. EP241021a: optical follow-up observations with the Liverpool Telescope
  53. Fermi GRB 241025A: Global MASTER-Net observations report
  54. Swift GRB 241025A: Global MASTER-Net observations report
  55. EP241025a (GRB 241025A): EP observations update
  56. GRB 241025A : SVOM/VT optical afterglow observations
  57. EP 241021A: Swift ToO observations
  58. EP241021a: Liverpool Telescope optical follow-up observations
  59. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  60. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  61. GRB 241025A: DDOTI Afterglow detection
  62. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  63. GRB 241025A: SVOM/GRM observation
  64. GRB 241025A: TRT optical afterglow observation
  65. Fermi GRB 241024B: Global MASTER-Net observations report
  66. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  67. GRB 241001A: ATCA radio observations
  68. EP241021a: No Detection in Fermi-GBM Observation
  69. GRB 241010A: VIRT Optical Upper Limit
  70. EP241021a: VLT/FORS2 redshift z = 0.75
  71. EP241021a: SAO RAS optical observations
  72. EP241021a: KAIT optical observations
  73. EP241021a: EP-FXT follow-up observation update
  74. IPN triangulation of GRB 241021A (long)
  75. EP241021a: Optical counterpart observations with the Liverpool Telescope
  76. EP241021a: 1.3m DFOT Optical observations
  77. EP241021a: GSP detects optical candidate counterpart
  78. EP241021a: Optical upper limits with Kinder observations
  79. EP241021a: TRT optical observations
  80. GRB 241018A: SVOM/C-GFT optical observations
  81. EP241021a: NOT likely optical counterpart
  82. EP EP241021a: Global MASTER-Net observations report
  83. GRB241017A: 1.3m DFOT optical upper limit
  84. GRB 241018A: 1.3m DFOT Optical upper limit
  85. GRB 241018A: EP-FXT afterglow detection
  86. EP241021a: GOTO optical upper limits
  87. Konus-Wind detection of GRB 241018A
  88. GRB 241018A: SVOM/GRM observation
  89. GRB 241018A/sb24101802: Mephisto optical upper limit
  90. GRB 241017A/sb24101702: Mephisto optical upper limit
  91. GRB 241018A: Mondy optical upper limit
  92. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  93. GRB 241018A: GROWTH-India telescope optical upper limit
  94. GRB241018A: XingLong Optical Upper Limit
  95. GRB 241018A: REM optical/NIR upper limits
  96. GRB 241018A: NOT optical observations
  97. GRB 241017A: SVOM/VT follow-up and optical upper limit
  98. GRB 241018A: SVOM/VT follow-up and optical candidate
  99. GRB 241018A: LCO/0.4m optical upper limits
  100. GRB 241018A: Swift ToO observations

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