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"

19542 results found.

  1. GRB 260925A: Swift/UVOT Upper Limits
  2. Konus-Wind detection of GRB 260924A
  3. GRB 260924A: Optical follow-up observations with Kinder
  4. GRB 260925A: Enhanced Swift-XRT position
  5. GRB 260925A: COLIBRÍ optical upper limits
  6. GRB 260925A: FRAM-Auger optical limit
  7. GRB 260924A: Ondrejov D50 optical afterglow detection
  8. EP260924a: J-band upper limit with WINTER
  9. GRB 260924A: SVOM/GRM observation
  10. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  11. GRB 260925A: Swift detection of a burst
  12. EP260924a: EP-WXT detection of an X-ray transient
  13. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  14. GRB 260924A: Swift/UVOT Detection
  15. GRB 260924A: GROWTH-India Telescope optical observations
  16. Konus-Wind detection of GRB 260922A
  17. GRB 260921A: SVOM/GRM observation
  18. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  19. GRB 260920A: SVOM/GRM observation
  20. GRB 260924A: NOT optical counterpart confirmation
  21. GRB 260924A: Enhanced Swift-XRT position
  22. GRB 260924A: Swift detection of a burst
  23. Trigger_21914: Swift ToO observations
  24. EP260806a: e-MERLIN detection at 5 GHz
  25. GRB 260922A: Ondrejov D50 optical limit
  26. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  27. GRB 260922A: J-band upper limit with WINTER
  28. GRB 260922A: Swift/UVOT Upper Limits
  29. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  30. GRB 260922A: COLIBRÍ optical upper limits
  31. GRB 260922A: Enhanced Swift-XRT position
  32. GRB 260922A: SVOM/C-GFT optical upper limit
  33. GRB 260922A: Swift detection of a burst
  34. GRB 260917C: AstroSat CZTI detection
  35. EP260920a: VLT/HAWK-I near-infrared candidate
  36. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  37. GRB 260921A: Swift detection of a burst
  38. EP260920b: LCO observations
  39. EP260920b: SVOM/VT optical observation
  40. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  41. EP260920b: COLIBRÍ optical observations
  42. EP260920b: LCO optical counterpart detection
  43. The EP-WXT trigger 01709318601 is likely a flaring star
  44. EP260920b: Einstein Probe detection of an X-ray transient
  45. EP-WXT detected a brightening of HMXB LS V +44 17
  46. EP260920a: NOT early time optical upper limits
  47. EP260920a: NOT optical upper limits
  48. EP260920a: SVOM/VT optical upper limits
  49. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  50. EP260920a: COLIBRÍ optical upper limits
  51. EP260920a: LCO optical counterpart candidate
  52. EP260920a: Einstein Probe detection of an X-ray transient
  53. GRB 260915A: VLT optical and near-infrared upper limits
  54. The EP-WXT trigger 01709318491 is likely a flaring star
  55. EP260917a: SVOM/VT optical upper limits
  56. GRB 260918A: SVOM/C-GFT optical upper limits
  57. GRB 260918A: SVOM/VT optical upper limits
  58. GRB 260917B: Mondy optical upper limit
  59. EP260917b: EP-WXT detection of an X-ray transient
  60. EP260917A: J-band upper limit with WINTER
  61. EP260917a: COLIBRÍ optical upper limits
  62. GRB 260918A: LCO optical upper limits
  63. EP260917a: Einstein Probe detection of an X-ray transient
  64. GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  65. GRB 260918A: SVOM detection of a burst
  66. GRB 260917B: FRAM-Auger optical limits
  67. GRB 260917B: WINTER J-band observations
  68. GRB 260917B: SVOM/VT optical observations
  69. GRB 260917B: LCO optical observation
  70. GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  71. GRB 260917B: SVOM detection of a faint burst
  72. GRB 260915A: J-band upper limit with WINTER
  73. GRB 260909A: NOEMA detection
  74. GRB 260914A: Mondy and TShAO optical observations
  75. GRB 260909A: Swift-XRT observations
  76. GRB 260915A: Swift ToO observations
  77. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  78. GRB 260915A: SVOM/C-GFT optical upper limits
  79. GRB 260915A: REM optical/NIR observations
  80. GRB 260914A: REM optical/NIR observations
  81. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  82. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB 260915A: NOT optical upper limit
  84. GRB 260915A: SVOM/VT optical upper limits from VHF data
  85. GRB 260915A: LCO optical upper limits
  86. EP Alert 260914.53: Global MASTER-Net observations report
  87. GRB 260915A: SVOM detection of a burst
  88. GRB 260914A: LCO optical observation
  89. GRB 260914A: SVOM/C-GFT optical observations
  90. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  91. GRB 260914A: SVOM detection of a burst
  92. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  93. GRB 260913A: SVOM/C-GFT optical upper limit
  94. GRB 260913A: SVOM detection of a faint burst
  95. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  96. GRB 260907A: SVOM/GRM observation
  97. GRB 260909A: CrAO and AbAO optical upper limits
  98. GRB 260909A: Swift ToO observations
  99. GRB 260909A: KAIT optical upper limit
  100. GRB 260903A: Swift-XRT observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov