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"

22053 results found.

  1. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  2. Fermi trigger No 741356809: Global MASTER-Net observations report
  3. Fermi GRB 240629A: Global MASTER-Net observations report
  4. Fermi trigger No 741296200: Global MASTER-Net observations report
  5. Fermi trigger No 741251380: Global MASTER-Net observations report
  6. GRB 240615A: SAI CMO J- band observations
  7. Fermi trigger No 741211696: Global MASTER-Net observations report
  8. EP240626a: Montarrenti Observatory optical upper limit
  9. EP240625a: GRANDMA Optical Upper Limits
  10. Konus-Wind detection of GRB 240619A
  11. EP240626a: EP-WXT detection of a fast X-ray transient
  12. Fermi GRB 240625B: Global MASTER-Net observations report
  13. EP240625a: NOT optical counterpart candidate
  14. EP240625a: EP-WXT detection of a fast X-ray transient
  15. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  16. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  17. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  18. Swift GRB 240624A: Global MASTER-Net observations report
  19. GRB240615A: Gemini-North observations of the BAT and XRT positions
  20. Fermi GRB 240624A: Global MASTER-Net observations report
  21. Fermi trigger No 740949590: Global MASTER-Net observations report
  22. GRB240615A: Gemini-North observations of the BAT and XRT positions
  23. GRB 240619A: detection of a radio counterpart with AMI-LA
  24. EP240618a: NOT further optical observations
  25. GRB 240619A: J-band detection with WINTER
  26. Fermi trigger No 740744838: Global MASTER-Net observations report
  27. EP240618a: NOT optical counterpart candidate
  28. GRB 240529A: JinShan optical observations
  29. EP240618a: GSP optical upper limit
  30. EP240617a: tentative Swift/XRT detection of the afterglow
  31. GRB 240619A: Swift-XRT probable afterglow detection
  32. GRB 240619A: Swift ToO observations
  33. GRB 240619A: GOTO candidate optical afterglow
  34. EP240618a: Abastumani optical observationsEP240618a
  35. GRB 240615A: NOT optical observations
  36. EP240618a: GRANDMA Optical Upper Limits
  37. EP240618a: TRT optical upper limit
  38. Fermi trigger No 740474239: Global MASTER-Net observations report
  39. Fermi GRB 240619A: Global MASTER-Net observations report
  40. EP240617a: STEP/T80S optical limits
  41. GRB 240615A: possible transient detection from Wendelstein observations
  42. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  43. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  44. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  45. Fermi trigger No 740430582: Global MASTER-Net observations report
  46. EP240617a: EP-WXT detection of a fast X-ray transient
  47. EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
  48. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  49. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  50. GRB 240615A: J-band upper limits from WINTER
  51. GRB 240615A: Swift-XRT observations
  52. X-ray transient EP240414a: Chandra late time observation
  53. Fermi trigger No 740221779: Global MASTER-Net observations report
  54. Fermi GRB 240616A: Global MASTER-Net observations report
  55. GRB 240615A: GOTO optical upper limits
  56. Fermi trigger No 740166710: Global MASTER-Net observations report
  57. GRB 240615A: Swift ToO observations
  58. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  59. Fermi GRB 240612B: Global MASTER-Net observations report
  60. Fermi GRB 240612A: Global MASTER-Net observations report
  61. Fermi GRB 240611A: Global MASTER-Net observations report
  62. Konus-Wind detection of GRB 240607A
  63. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  64. GRB 240529A: LBT optical detection and late temporal decay
  65. Trigger 1236151: Swift detection of EXO 0748-676
  66. Fermi GRB 240610A: Global MASTER-Net observations report
  67. Fermi trigger No 739632045: Global MASTER-Net observations report
  68. Fermi GRB 240608A: Global MASTER-Net observations report
  69. Konus-Wind detection of GRB 240606B
  70. Fermi trigger No 739506569: Global MASTER-Net observations report
  71. Fermi GRB 240607A: Global MASTER-Net observations report
  72. GRB 240529A: NOEMA detection
  73. GRB 240529A: radio detection with AMI-LA
  74. Fermi trigger No 739373591: Global MASTER-Net observations report
  75. GRB 240606B: Swift-XRT afterglow detection
  76. Swift GRB240606.15: Global MASTER-Net observations report
  77. GRB 240606B: Swift ToO observations
  78. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  79. Fermi GRB 240604A: Global MASTER-Net observations report
  80. Fermi GRB 240605A: Global MASTER-Net observations report
  81. Fermi GRB 240605C: Global MASTER-Net observations report
  82. GRB 240529A: SAO RAS optical observations
  83. Fermi GRB 240603C: Global MASTER-Net observations report
  84. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  85. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  86. GRB 240529A: MASTER prompt OT detection
  87. GRB 240529A: continued SAO RAS optical observations
  88. Fermi GRB 240602A: Global MASTER-Net observations report
  89. GRB 240529A: OSN optical detection
  90. GRB 240529A: further SAO RAS optical observations
  91. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  92. LXT 240528A: GSP optical upper limit
  93. GRB 240529A: 1.3m DFOT Optical observations
  94. GRB 240529A : Mondy optical observations
  95. Konus-Wind detection of GRB 240529A
  96. GRB 240529A: SAO RAS optical observations
  97. GRB 240529A: optical photometry from Konkoly
  98. GRB 240529A: T193/MISTRAL observations
  99. GRB 240529A: AKO Optical Afterglow Detection
  100. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO

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