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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"

27928 results found.

  1. GRB 260917B: SVOM detection of a faint burst
  2. GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
  3. Fermi trigger No 811304653: Global MASTER-Net observations report
  4. GRB 260915A: J-band upper limit with WINTER
  5. Fermi trigger No 811264269: Global MASTER-Net observations report
  6. GRB 260909A: NOEMA detection
  7. GRB 260914A: Mondy and TShAO optical observations
  8. GRB 260914A: SVOM/ECLAIRs refined analysis
  9. GRB 260909A: Swift-XRT observations
  10. GRB 260916A: MAXI/GSC detection
  11. MAXI GRB260916.37: Global MASTER-Net observations report
  12. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  13. GRB 260915A: SVOM/C-GFT optical upper limits
  14. GRB 260915A: EP-FXT follow-up observation
  15. GRB 260915A: SVOM/VT refined early optical upper limits
  16. GRB 260915A: REM optical/NIR observations
  17. GRB 260914A: REM optical/NIR observations
  18. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  19. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  20. GRB 260915A: NOT optical upper limit
  21. SVOM GRB260915.05: Global MASTER-Net observations report
  22. GRB 260915A: SVOM/VT optical upper limits from VHF data
  23. Fermi GBM Sub-Threshold Detection of GRB 260915A
  24. GRB 260915A: LCO optical upper limits
  25. EP Alert 260914.53: Global MASTER-Net observations report
  26. GRB 260914A: EP-FXT follow-up observation
  27. GRB 260915A: SVOM detection of a burst
  28. Fermi GBM Sub-Threshold Detection of GRB 260914A
  29. GRB 260914A: LCO optical observation
  30. GRB 260914A: SVOM/C-GFT optical observations
  31. GRB 260914A: SVOM/VT optical observation from VHF data
  32. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  33. SVOM GRB260914.47: Global MASTER-Net observations report
  34. GRB 260914A: SVOM detection of a burst
  35. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  36. GRB 260818A: Continued ATCA observations
  37. SVOM GRB260913.32: Global MASTER-Net observations report
  38. GRB 260913A: SVOM/C-GFT optical upper limit
  39. GRB 260913A: SVOM detection of a faint burst
  40. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  41. GRB 260907A: SVOM/GRM observation
  42. GRB 260909A: CrAO and AbAO optical upper limits
  43. GRB 260909A: KAIT optical upper limit
  44. GRB 260903A: Swift-XRT observations
  45. GRB 260909A: OHP/T193 z-band upper limit
  46. GRB 260909A: VLT optical and near-infrared upper limits
  47. EP Alert 260909.53: Global MASTER-Net observations report
  48. GRB 260909A: EP-FXT follow-up observation
  49. EP260806a: NOEMA detection
  50. EP260623a: NOEMA detections
  51. GRB 260909A: Mondy optical observations and afterglow candidate
  52. GRB 260909A: Xinglong 2.16m optical upper limit
  53. GRB 260909A: SVOM/C-GFT optical upper limit
  54. GRB 260909A: SVOM detection of a burst
  55. Fermi trigger No 810554827: Global MASTER-Net observations report
  56. EP Alert 260908.60: Global MASTER-Net observations report
  57. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  58. Fermi GRB 260907B: Global MASTER-Net observations report
  59. GRB 260903A: SAO RAS optical upper limit
  60. Fermi GRB 260907A: Global MASTER-Net observations report
  61. EP260903a: EP-FXT follow-up observation
  62. EP Alert 260905.11: Global MASTER-Net observations report
  63. GRB 260903A: J-band upper limit with WINTER
  64. EP Alert 260903.47: Global MASTER-Net observations report
  65. GRB260903A: Liverpool Telescope optical observations
  66. GRB 260903A: SAO RAS optical observations
  67. GRB 260830A: GECAM-B detection of a burst
  68. EP260903a: EP-WXT detection of a fast X-ray transient
  69. EP Alert 260903.62: Global MASTER-Net observations report
  70. GRB 260830A: Insight-HXMT/HE detection
  71. GRB 260903A: EP-FXT follow-up observation
  72. GRB 260903A: OHP/T193 optical afterglow detection
  73. NuSTAR Transient 260828: SOAR Optical Upper Limits
  74. SVOM GRB260903A: Global MASTER-Net observations report
  75. GRB 260903A: LCO optical counterpart detection
  76. GRB 260827A: Insight-HXMT/HE detection
  77. EP260901a: SVOM/VT optical upper limits
  78. EP260901a: EP-FXT follow-up observation
  79. GRB 260829A: SVOM/GRM observation
  80. GRB 260818A: ATCA detection of a candidate radio counterpart
  81. EP260830a: EP-FXT follow-up observation
  82. EP260901a: Global MASTER-Net observations report
  83. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  84. NuSTAR Transient 260828: LCO Optical Upper Limits
  85. EP260901a: EP-WXT detection of a fast X-ray transient
  86. GRB 260830A: NuSTAR detection of prompt emission
  87. GRB 260831B: LCO optical upper limits
  88. EP260830a: Global MASTER-Net observations report
  89. EP260830a: EP-WXT detection of a fast X-ray transient
  90. GRB 260827A: SVOM/GRM observation
  91. NuSTAR 260828: a 1100s hard X-ray transient
  92. GRB 260831B: SVOM detection of a possible burst
  93. GRB 260827A: Glowbug gamma-ray detection
  94. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  95. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  96. GRB 260825A: SVOM/GRM observation of a long burst
  97. GRB 260829A: Fermi GBM Detection
  98. GRB 260825A: AstroSat CZTI detection
  99. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  100. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube

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