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"

20869 results found.

  1. GRB 260909A: CrAO and AbAO optical upper limits
  2. GRB 260909A: SVOM/ECLAIRs refined analysis
  3. GRB 260910B: GOTO tentative optical counterpart candidates
  4. GRB 260909A: Swift ToO observations
  5. GRB 260909A: KAIT optical upper limit
  6. GRB 260903A: Swift-XRT observations
  7. EP260806a: VLA+ALMA radio detections
  8. GRB 260909A: OHP/T193 z-band upper limit
  9. EP Alert 260909.53: Global MASTER-Net observations report
  10. EP260806a: NOEMA detection
  11. EP260623a: NOEMA detections
  12. GRB 260909A: Mondy optical observations and afterglow candidate
  13. GRB 260909A: SVOM/C-GFT optical upper limit
  14. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  15. Fermi trigger No 810554827: Global MASTER-Net observations report
  16. EP Alert 260908.60: Global MASTER-Net observations report
  17. GRB 260903A: Swift ToO observations
  18. Fermi GRB 260907B: Global MASTER-Net observations report
  19. GRB 260903A: SAO RAS optical upper limit
  20. Fermi GRB 260907A: Global MASTER-Net observations report
  21. EP260903a: EP-FXT follow-up observation
  22. EP Alert 260905.11: Global MASTER-Net observations report
  23. GRB 260903A: J-band upper limit with WINTER
  24. EP Alert 260903.47: Global MASTER-Net observations report
  25. GRB 260903A: SVOM/ECLAIRs refined analysis
  26. GRB260903A: Liverpool Telescope optical observations
  27. GRB 260903A: SAO RAS optical observations
  28. EP260903a: EP-WXT detection of a fast X-ray transient
  29. EP Alert 260903.62: Global MASTER-Net observations report
  30. GRB 260903A: OHP/T193 optical afterglow detection
  31. GRB 260903A: NOT optical observations and afterglow fading
  32. NuSTAR Transient 260828: SOAR Optical Upper Limits
  33. SVOM GRB260903A: Global MASTER-Net observations report
  34. GRB 260903A: LCO optical observations
  35. GRB 260903A: SVOM/VT optical candidate
  36. GRB 260818A: ATCA detection of a candidate radio counterpart
  37. EP260901a: Global MASTER-Net observations report
  38. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  39. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  40. NuSTAR Transient 260828: LCO Optical Upper Limits
  41. EP260901a: EP-WXT detection of a fast X-ray transient
  42. EP260830a: Global MASTER-Net observations report
  43. EP260830a: EP-WXT detection of a fast X-ray transient
  44. NuSTAR 260828: a 1100s hard X-ray transient
  45. EP260727a: ATCA 10 GHz detection
  46. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  47. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  48. GRB 260818B: VLT optical and nIR observations
  49. GRB 260818B: TNG NIR observations
  50. MAXI GRB260827.40: Global MASTER-Net observations report
  51. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  52. GRB 260818B: 6 GHz VLA observations
  53. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  54. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  55. GRB 260808B: SAO RAS observations of the optical rebrightening
  56. EP260822a: Global MASTER-Net observations report
  57. EP Alert 260820.31: Global MASTER-Net observations report
  58. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  59. GRB 260807A: EP-FXT follow-up observations
  60. GRB 260822A: SVOM/ECLAIRs refined analysis
  61. GRB 260809A: SVOM/ECLAIRs refined analysis
  62. GRB 260822A: SVOM/VT optical upper limits
  63. IceCube Alert 260825A: Global MASTER-Net observations report
  64. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  65. GRB 260822A: EP/FXT follow-up observations
  66. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  67. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  68. GRB 260822A: GOTO optical counterpart detection
  69. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  70. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  71. EP260822a: Einstein Probe detection of a fast X-ray transient
  72. GRB 260822A: LCO optical upper limits
  73. GRB 260822A: GOTO optical upper limit
  74. GRB 260822A: SVOM detection of a short burst
  75. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  76. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  77. GRB 260818B: VLA radio observations
  78. GRB 260818B: SVOM/C-GFT optical upper limit
  79. IceCube Alert 260821A: Global MASTER-Net observations report
  80. GRB 260818A: J-band observations with WINTER
  81. GRB 260818B: SVOM/ECLAIRs refined analysis
  82. GRB 260818A: SVOM/ECLAIRs refined analysis
  83. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  84. EP260806a: SAO RAS multicolor optical observations
  85. EP260812a: AbAO optical upper limit
  86. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  87. EP260806a: NUTTELA-TAO optical observations
  88. EP260812a: AZT-22 optical upper limit
  89. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  90. EP260806a: WFST optical observations
  91. EP260812b: Optical upper limit with Kinder
  92. GRB 260808B: Liverpool Telescope further optical observations
  93. EP260812a: NOT and Liverpool Telescope upper limits:
  94. EP260812b: Liverpool Telescope observations
  95. EP260812b: GOTO detection of the optical counterpart
  96. EP260812a: SVOM/C-GFT optical upper limit
  97. EP260812b: COLIBRÍ optical observations
  98. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  99. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  100. GRB 260809A: SAO RAS optical 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