Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"

27319 results found.

  1. EP260306a: Mondy optical upper limit
  2. Fermi GRB 260310B: Global MASTER-Net observations report
  3. Fermi GRB 260310A: Global MASTER-Net observations report
  4. GRB 260208A: radio detection with the VLA
  5. GRB 260307A: Glowbug gamma-ray detection
  6. Fermi GBM Sub-Threshold Detection of GRB 260307B
  7. GRB 260307B: Mephisto optical upper limits
  8. GRB 260307B: possible NOT optical counterpart
  9. GRB 260307B: SVOM/VT upper limit with X band data analysis
  10. Fermi GRB 260307A: Global MASTER-Net observations report
  11. GRB260307B: GROWTH-India Telescope optical upper limit
  12. GRB 260307B: SVOM/VT optical candidate
  13. GRB 260307B: SVOM/C-GFT upper limit
  14. GRB 260307B: SVOM detection of a burst
  15. EP260306a: refined analysis of the EP-WXT and EP-FXT observations
  16. GRB 260207A: TESS Detection and Possible VLA Counterpart
  17. EP260302a: SVOM/VT optical observation
  18. EP260306a: Gemini-North redshift z = 4.773
  19. EP260306a: SVOM/VT optical observation
  20. EP260302a: Gemini-South redshift z = 1.535
  21. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  22. EP260306a: Einstein Probe detection of an X-ray transient
  23. EP260302a: Optical afterglow rebrightening
  24. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  25. GRB 260303A: 1.3m DFOT optical upper limit
  26. Fermi GRB 260305A: Global MASTER-Net observations report
  27. GRB 260303B: AstroSat CZTI detection
  28. GRB 260303A: SVOM/VT optical observations
  29. GRB 260303A: J-band observations with WINTER
  30. GRB 260303B: NuSTAR detection of prompt emission
  31. EP260302a: Global MASTER-Net observations report
  32. Fermi GRB 260303B: Global MASTER-Net observations report
  33. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  34. EP260302a: analysis of the follow-up EP-FXT observation
  35. EP260302a: LCO observations
  36. EP260302a: BOOTES-7 optical counterpart detection at early times
  37. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  38. GRB 260303A: SVOM detection of a burst
  39. GRB 260228A: EP-FXT follow-up observation
  40. EP260302a: Einstein Probe detection of an X-ray transient
  41. The EP-WXT trigger 01709258736: Las Cumbres discovery of the optical counterpart
  42. GRB 251130B: TERI Gamma-ray detection
  43. GRB 260208A: TERI Gamma-ray detection
  44. EP260227a: Mondy optical observations
  45. GRB 260228A: CAHA 2.2m telescope optical upper limit
  46. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  47. EP260227a: Mephisto optical detection
  48. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  49. EP260227a: SVOM/VT optical observation
  50. GRB 260228A: SVOM/VT optical upper limits
  51. GRB 260225D: SVOM/GRM observation
  52. EP260227A: 3.6m DOT optical afterglow detection
  53. GRB 260225B: SVOM/GRM observation
  54. EP260227a: Liverpool Telescope optical observations
  55. EP260227a: LCOGT Optical Observations
  56. GRB 260226A: Asiago r-band upper limit
  57. EP260227a: Liverpool Telescope observations
  58. EP260227a: COLIBRÍ optical observations
  59. EP260227a: NOT optical observations
  60. EP260227a: Global MASTER-Net observations report
  61. EP260227a: Einstein Probe detection of an X-ray transient and refined analysis
  62. The EP-WXT trigger 01709258681 (EP260227a?): Las Cumbres follow-up observation of the optical counterpart
  63. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  64. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  65. EP260214a: VLT/FORS2 optical observations
  66. GRB 260225A: WINTER J-band upper limit
  67. GRB 260226A: COLIBRÍ optical upper limits
  68. GRB 260226A: LCOGT Optical Upper Limit
  69. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  70. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  71. GRB 260226A: Glowbug gamma-ray detection
  72. GRB 260226A: NuSTAR detection of bright prompt emission
  73. GRB 260226A : GROWTH-India Telescope optical observations
  74. GRB 260226A: LAST optical upper limit
  75. GRB 260226A: Fermi GBM observation
  76. LAT GRB260226.44: Global MASTER-Net observations report
  77. Fermi GRB 260226A: Global MASTER-Net observations report
  78. GRB 260226A: AstroSat CZTI detection of bright long burst
  79. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  80. EP260224a: LCO optical upper limits
  81. GRB 260225A: EP-FXT follow-up observation
  82. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  83. GRB 260223A: Fermi GBM Observation
  84. GRB 260225A: SVOM/VT optical upper limits
  85. EP260223a: Liverpool Telescope upper limits
  86. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  87. EP260224a: Einstein Probe detection of an X-ray transient
  88. EP 260225.148: COLIBRÍ Confirmation of flaring star
  89. EP260223a: Xinglong optical upper limit
  90. GRB 260223A: Glowbug gamma-ray detection
  91. EP260213a: Mephisto optical upper limits
  92. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  93. sb26021801: SVOM/C-GFT upper limit
  94. EP260223a: COLIBRÍ optical upper limits
  95. EP260223a: Einstein Probe detection of an X-ray transient
  96. GRB 260223A: SVOM/GRM observation
  97. GRB 260223A: COLIBRÍ further optical observations and a brightening
  98. EP260221a: Optical upper limit with Kinder observations
  99. GRB 260223A: COLIBRÍ optical observations
  100. GRB 260223A: DDOTI Optical Candidate

Advanced

Download all Circulars as a .tar.gz archive:
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