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"
  1. EP260514a: SVOM/VT optical candidate
  2. Fermi GRB 260516B: Global MASTER-Net observations report
  3. GRB 260516B: Fermi GBM Final Real-time Localization
  4. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  5. GRB 260515A: SVOM/VT optical observations
  6. GRB 260515A: OHP/T193 optical observations
  7. EP260514a: COLIBRÍ optical upper limits
  8. GRB 260516A: Fermi GBM Final Real-time Localization
  9. GRID detection of GRB 260507A
  10. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  11. GRB 260515A: LCO optical observations
  12. SVOM GRB 260515A: Global MASTER-Net observations report
  13. GRB 260515A: NOT optical observations.
  14. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  15. GRB 260515A: SVOM/VT optical candidate from VHF data
  16. GRB 260515A: JinShan optical counterpart candidate
  17. GRB 260515A: SVOM detection of a burst
  18. GRB 260510C: Glowbug gamma-ray detection
  19. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  20. EP260514a: GROWTH-India Telescope optical upper limit
  21. GRB 260511B: NOT optical observations
  22. Konus-Wind detection of GRB 260512A
  23. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  24. GRB 260511B: GMG Optical Upper Limit
  25. EP260514a: Global MASTER-Net observations report
  26. EP260514a: Einstein Probe detection of a fast X-ray transient
  27. EP260512a: LCO optical upper limits
  28. IPN triangulation of GRB 260512A
  29. GRB 260511B: Mephisto multi-band optical followup
  30. Fermi GRB 260514A: Global MASTER-Net observations report
  31. GRB 260512A: AstroSat CZTI detection
  32. The EP-WXT trigger 01709262077 is likely a flaring star
  33. EP260512a: EP-FXT follow-up observation
  34. EP260507a: Xinglong Schmidt optical counterpart detection
  35. GRB 260514A: Fermi GBM Final Real-time Localization
  36. EP260512a: Global MASTER-Net observations report
  37. Fermi GRB 260513A: Global MASTER-Net observations report
  38. Fermi GRB 260512A: Global MASTER-Net observations report
  39. GRB 260511B: further SAO RAS optical observations
  40. GRB 260513A: Fermi GBM Final Real-time Localization
  41. GRB 260509A: SVOM/VT optical observations
  42. Konus-Wind detection of GRB 260511B
  43. The EP-WXT trigger 01709262036 is likely a flaring star
  44. EP260512a: COLIBRÍ optical upper limits
  45. EP260512a: Einstein Probe detection of an X-ray transient
  46. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  47. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  48. GRB 260512A: NuSTAR detection of prompt emission
  49. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  50. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  51. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  52. GRB 260512A: Fermi GBM Final Real-time Localization
  53. GRB 260511A: Glowbug gamma-ray detection
  54. Konus-Wind detection of GRB 260511A
  55. MASS-Cube (GRID 2.0) detection of GRB 260511A
  56. MASS-Cube (GRID 2.0) detection of GRB 260507A
  57. GRB 260511B: SAO RAS optical observations
  58. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  59. GRB 260511B: FRAM-ORM optical detection
  60. GRB 260511A: EP-FXT follow-up observation
  61. GRB 260511B: EP-FXT follow-up observation
  62. GRB 260511B: LCO optical counterpart detection
  63. GRB260511B: MAO/AZT-22 optical observations
  64. GRB 260511A: SVOM/VT optical observations
  65. GRB 260511B: LCO optical observations
  66. GRB 260511B: OHP/T193 spectroscopic observations
  67. GRB 260511B: GOTO optical counterpart detection
  68. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  69. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  70. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  71. GRB 260511B: SVOM/VT optical observations
  72. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  73. GRB 260510B: EP-FXT follow-up observation
  74. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  75. GRB 260510C: Fermi GBM Observation
  76. GRB 260509A: SAO RAS optical observations
  77. GRB 260511A: REM near-infrared detection
  78. GRB 260511B: GROWTH-India Telescope optical observations
  79. GRB 260511B: AstroSat CZTI detection
  80. GRB 260506B: Glowbug gamma-ray detection
  81. GRB 260506A: Glowbug gamma-ray detection of a short burst
  82. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  83. GRB 260511B: NuSTAR detection of prompt emission
  84. GRB 260511A: NuSTAR detection of prompt emission
  85. GRB 260511B: Fermi GBM Detection
  86. GRB 260511C: Fermi GBM Final Real-time Localization
  87. GRB 260511B: SVOM/VT optical observation with VHF data
  88. GRB 260511B: TRT optical observation
  89. GRB 260510B: SVOM/ECLAIRs refined analysis
  90. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  91. GRB 260511A: Fermi GBM Detection
  92. GRB 260511B SVOM/C-GFT optical counterpart detection
  93. EP260509a: LCO optical upper limits
  94. GRB 260511A: UTGO H50 optical afterglow observation
  95. GRB 260510C: AstroSat CZTI detection
  96. GRB 260511B: SVOM detection of a burst
  97. GRB 260511B: Fermi GBM Final Real-time Localization
  98. GRB 260510C: EP-FXT follow-up observation
  99. GRB 260510C: SVOM/VT optical counterpart confirmation
  100. EP260509a: EP-FXT non-detection and upper limit

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