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"

19545 results found.

  1. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  2. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  3. Swift Trigger 1513439 is probably not a GRB
  4. GRB 260925A: Swift/UVOT Upper Limits
  5. Konus-Wind detection of GRB 260924A
  6. GRB 260924A: Optical follow-up observations with Kinder
  7. GRB 260925A: Enhanced Swift-XRT position
  8. GRB 260925A: COLIBRÍ optical upper limits
  9. GRB 260925A: FRAM-Auger optical limit
  10. GRB 260924A: Ondrejov D50 optical afterglow detection
  11. EP260924a: J-band upper limit with WINTER
  12. GRB 260924A: SVOM/GRM observation
  13. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  14. GRB 260925A: Swift detection of a burst
  15. EP260924a: EP-WXT detection of an X-ray transient
  16. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  17. GRB 260924A: Swift/UVOT Detection
  18. GRB 260924A: GROWTH-India Telescope optical observations
  19. Konus-Wind detection of GRB 260922A
  20. GRB 260921A: SVOM/GRM observation
  21. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  22. GRB 260920A: SVOM/GRM observation
  23. GRB 260924A: NOT optical counterpart confirmation
  24. GRB 260924A: Enhanced Swift-XRT position
  25. GRB 260924A: Swift detection of a burst
  26. Trigger_21914: Swift ToO observations
  27. EP260806a: e-MERLIN detection at 5 GHz
  28. GRB 260922A: Ondrejov D50 optical limit
  29. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  30. GRB 260922A: J-band upper limit with WINTER
  31. GRB 260922A: Swift/UVOT Upper Limits
  32. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  33. GRB 260922A: COLIBRÍ optical upper limits
  34. GRB 260922A: Enhanced Swift-XRT position
  35. GRB 260922A: SVOM/C-GFT optical upper limit
  36. GRB 260922A: Swift detection of a burst
  37. GRB 260917C: AstroSat CZTI detection
  38. EP260920a: VLT/HAWK-I near-infrared candidate
  39. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  40. GRB 260921A: Swift detection of a burst
  41. EP260920b: LCO observations
  42. EP260920b: SVOM/VT optical observation
  43. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  44. EP260920b: COLIBRÍ optical observations
  45. EP260920b: LCO optical counterpart detection
  46. The EP-WXT trigger 01709318601 is likely a flaring star
  47. EP260920b: Einstein Probe detection of an X-ray transient
  48. EP-WXT detected a brightening of HMXB LS V +44 17
  49. EP260920a: NOT early time optical upper limits
  50. EP260920a: NOT optical upper limits
  51. EP260920a: SVOM/VT optical upper limits
  52. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  53. EP260920a: COLIBRÍ optical upper limits
  54. EP260920a: LCO optical counterpart candidate
  55. EP260920a: Einstein Probe detection of an X-ray transient
  56. GRB 260915A: VLT optical and near-infrared upper limits
  57. The EP-WXT trigger 01709318491 is likely a flaring star
  58. EP260917a: SVOM/VT optical upper limits
  59. GRB 260918A: SVOM/C-GFT optical upper limits
  60. GRB 260918A: SVOM/VT optical upper limits
  61. GRB 260917B: Mondy optical upper limit
  62. EP260917b: EP-WXT detection of an X-ray transient
  63. EP260917A: J-band upper limit with WINTER
  64. EP260917a: COLIBRÍ optical upper limits
  65. GRB 260918A: LCO optical upper limits
  66. EP260917a: Einstein Probe detection of an X-ray transient
  67. GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  68. GRB 260918A: SVOM detection of a burst
  69. GRB 260917B: FRAM-Auger optical limits
  70. GRB 260917B: WINTER J-band observations
  71. GRB 260917B: SVOM/VT optical observations
  72. GRB 260917B: LCO optical observation
  73. GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  74. GRB 260917B: SVOM detection of a faint burst
  75. GRB 260915A: J-band upper limit with WINTER
  76. GRB 260909A: NOEMA detection
  77. GRB 260914A: Mondy and TShAO optical observations
  78. GRB 260909A: Swift-XRT observations
  79. GRB 260915A: Swift ToO observations
  80. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  81. GRB 260915A: SVOM/C-GFT optical upper limits
  82. GRB 260915A: REM optical/NIR observations
  83. GRB 260914A: REM optical/NIR observations
  84. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  85. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  86. GRB 260915A: NOT optical upper limit
  87. GRB 260915A: SVOM/VT optical upper limits from VHF data
  88. GRB 260915A: LCO optical upper limits
  89. EP Alert 260914.53: Global MASTER-Net observations report
  90. GRB 260915A: SVOM detection of a burst
  91. GRB 260914A: LCO optical observation
  92. GRB 260914A: SVOM/C-GFT optical observations
  93. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  94. GRB 260914A: SVOM detection of a burst
  95. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  96. GRB 260913A: SVOM/C-GFT optical upper limit
  97. GRB 260913A: SVOM detection of a faint burst
  98. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  99. GRB 260907A: SVOM/GRM observation
  100. GRB 260909A: CrAO and AbAO optical upper limits

Advanced

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