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"

20361 results found.

  1. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  2. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  3. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  4. EP260526a: SVOM/VT optical upper limits
  5. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  6. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  7. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  8. EP260527a/GRB 260527A: EP-FXT follow-up observation
  9. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  10. EP260527a: SVOM/VT optical observation
  11. EP260527a: COLIBRÍ optical detection
  12. EP260527a: Einstein Probe detection of a fast X-ray transient
  13. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  14. EP260526a: LCO optical upper limits
  15. EP260526a: Einstein Probe detection of a fast X-ray transient
  16. EP260526.405: COLIBRÍ optical upper limits
  17. The EP-WXT trigger 01709266106 is not a real source
  18. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  19. EP-WXT 01709266106: NOT optical upper limits
  20. Fermi GRB 260525A: Global MASTER-Net observations report
  21. GRB 260523B: AstroSat CZTI detection
  22. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  23. GRB 260511A: iTelescope T-75 optical detection
  24. GRB 260520B: SVOM/GRM observation
  25. GRB 260509A: SVOM/ECLAIRs refined analysis
  26. GRB 260516D: SVOM/ECLAIRs refined analysis
  27. GRB 260515A: SVOM/ECLAIRs refined analysis
  28. GRB 260421B: radio detection with the VLA
  29. GRID detection of GRB 260511A
  30. GRB 260509A: CrAO ZTSh optical upper limit
  31. GRB 260516D: GOTO optical counterpart detection
  32. GRB 260516D: LCO optical observations
  33. GRB 260515A: further Liverpool Telescope observations
  34. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  35. GRB 260516D: GROWTH-India Telescope optical detection
  36. GRB 260516D: SVOM/VT optical bright candidate
  37. GRB 260515A: CrAO ZTSh BVRI optical observations
  38. GRB 260515A: LCO optical counterpart detection
  39. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  40. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  41. EP260514a: NOT optical counterpart confirmation
  42. EP260514a: TRT optical counterpart candidate
  43. EP260514a: SVOM/VT optical candidate
  44. GRB 260515A: OHP/T193 optical observations
  45. EP260514a: COLIBRÍ optical upper limits
  46. GRID detection of GRB 260507A
  47. GRB 260515A: LCO optical observations
  48. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  49. GRB 260515A: SVOM/VT optical candidate from VHF data
  50. GRB 260515A: JinShan optical counterpart candidate
  51. GRB 260515A: SVOM detection of a burst
  52. EP260514a: GROWTH-India Telescope optical upper limit
  53. GRB 260511B: GMG Optical Upper Limit
  54. EP260514a: Einstein Probe detection of a fast X-ray transient
  55. EP260512a: LCO optical upper limits
  56. GRB 260511B: Mephisto multi-band optical followup
  57. EP260512a: EP-FXT follow-up observation
  58. EP260507a: Xinglong Schmidt optical counterpart detection
  59. GRB 260511B: further SAO RAS optical observations
  60. EP260512a: COLIBRÍ optical upper limits
  61. EP260512a: Einstein Probe detection of an X-ray transient
  62. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  63. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  64. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  65. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  66. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  67. MASS-Cube (GRID 2.0) detection of GRB 260511A
  68. MASS-Cube (GRID 2.0) detection of GRB 260507A
  69. GRB 260511B: SAO RAS optical observations
  70. GRB 260511B: FRAM-ORM optical detection
  71. GRB 260511B: LCO optical counterpart detection
  72. GRB260511B: MAO/AZT-22 optical observations
  73. GRB 260511B: LCO optical observations
  74. GRB 260511B: OHP/T193 spectroscopic observations
  75. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  76. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  77. GRB 260509A: SAO RAS optical observations
  78. GRB 260511A: REM near-infrared detection
  79. GRB 260511B: GROWTH-India Telescope optical observations
  80. GRB 260511B: AstroSat CZTI detection
  81. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  82. GRB 260511B: SVOM/VT optical observation with VHF data
  83. GRB 260511B: TRT optical observation
  84. GRB 260510B: SVOM/ECLAIRs refined analysis
  85. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  86. GRB 260511B SVOM/C-GFT optical counterpart detection
  87. EP260509a: LCO optical upper limits
  88. GRB 260511A: UTGO H50 optical afterglow observation
  89. GRB 260511B: SVOM detection of a burst
  90. EP260509a: EP-FXT non-detection and upper limit
  91. GRB 260511A: SVOM/VT optical observation with VHF data
  92. GRB 260511A: KAIT optical afterglow observations
  93. GRB 260511A: LCO optical afterglow detection
  94. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  95. GRB 260511A: TRT optical counterpart detection
  96. GRB 260511A: SVOM detection of a bright burst
  97. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  98. GRB 260510B: GOTO early upper limit
  99. GRB 260510C: SVOM detection of a burst
  100. GRB 260510B: LCO optical upper limits

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