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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"

11529 results found.

  1. GRB 241013A: Fermi GBM Final Real-time Localization
  2. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  3. GRB 241011A: Fermi GBM Final Real-time Localization
  4. Fermi trigger No 750211959: Global MASTER-Net observations report
  5. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  6. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  7. Fermi trigger No 750291012: Global MASTER-Net observations report
  8. Fermi GRB 241010B: Global MASTER-Net observations report
  9. GRB 241010B: Fermi GBM Final Real-time Localization
  10. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  11. GRB 241008A: Fermi GBM Observation
  12. GRB 241008A: Fermi-LAT detection
  13. GRB 241002B: Swift-XRT afterglow detection
  14. Fermi GRB 241008A: Global MASTER-Net observations report
  15. GRB 241008A: BALROG localization (Fermi Trigger 750117609 / GRB 241008917)
  16. GRB 241008A: Fermi GBM Final Real-time Localization
  17. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  18. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  19. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  20. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  21. GRB 240930B: SVOM/C-GFT optical upper limit
  22. Fermi trigger No 749721670: Global MASTER-Net observations report
  23. GRB 240930B / EP 240930a: SVOM/GRM observation
  24. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  25. GRB 241002B: Fermi GBM Observation
  26. Fermi trigger No 749735279: Global MASTER-Net observations report
  27. Fermi trigger No 749630753: Global MASTER-Net observations report
  28. Fermi trigger No 749693019: Global MASTER-Net observations report
  29. GRB 241002B: Swift-XRT observations
  30. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  31. GRB 241002B: Swift ToO observations
  32. GRB 241002B: PRIME near-infrared detection
  33. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  34. IPN triangulation of GRB 240930B / EP 240930a
  35. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  36. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  37. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  38. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  39. EP240930a: Liverpool Telescope observations
  40. GRB 241002B: GOTO optical counterpart candidate
  41. GRB 240929A: Liverpool Telescope prompt followup observations
  42. Fermi GRB 241002B: Global MASTER-Net observations report
  43. GRB 241002B: Fermi GBM Final Real-time Localization
  44. GRB 240930B: Fermi GBM Observation
  45. GRB 240930B: GRBAlpha detection
  46. GRB 240929A: GRBAlpha detection
  47. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  48. EP240930a: EP-FXT follow-up observation update
  49. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  50. EP240930a: GOTO optical upper limits
  51. GRB 240929A: SVOM/GRM observation
  52. EP240930a: EP-WXT detection of a fast X-ray transient
  53. GRB 240929A : Leavitt Observatory optical upper limit
  54. Fermi GRB 240930B: Global MASTER-Net observations report
  55. GRB 240930B: Fermi GBM Final Real-time Localization
  56. GRB 240825A: LBT optical observations
  57. Fermi GRB 240930A: Global MASTER-Net observations report
  58. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  59. GRB 240930A: Fermi GBM Final Real-time Localization
  60. Fermi trigger No 749339671: Global MASTER-Net observations report
  61. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  62. GRB 240929A long GRB detected by INTEGRAL
  63. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  64. Fermi GRB 240929A: Global MASTER-Net observations report
  65. GRB 240929A: Fermi GBM Final Real-time Localization
  66. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  67. Konus-Wind detection of GRB 240912A
  68. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  69. Konus-Wind detection of GRB 240905B
  70. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  71. Konus-Wind detection of GRB 240918B
  72. IPN triangulation of GRB 240918B
  73. GRB 240905B: VZLUSAT-2 detection
  74. GRB 240918B: AstroSat CZTI detection
  75. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  76. GRB 240414A: further radio observations with the VLA
  77. GRB 240919A / EP240919a: SVOM/GRM observation
  78. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  79. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  80. GRB 240910A: radio detection with the VLA
  81. EP240919a: JinShan optical upper limits
  82. EP240919a is likely a GRB event
  83. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  84. GRB 240918B: Fermi GBM Detection
  85. Fermi GRB 240918A: Global MASTER-Net observations report
  86. GRB 240918A: Fermi GBM Final Real-time Localization
  87. GRB 240916A: GRBAlpha detection
  88. GRB 240914B: GRBAlpha detection
  89. GRB 240916A: NOT optical observation
  90. IPN triangulation of GRB 240913C / EP 240913a
  91. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  92. GRB 240916A: Fermi GBM Observation
  93. GRB 240821A: radio observation with the VLA
  94. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  95. GRB 240916A: Swift-XRT afterglow detection
  96. GRB 240916A: Swift ToO observations
  97. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  98. GRB 240916B: Fermi GBM Final Real-time Localization
  99. GRB 240914B: Fermi GBM Final Localization
  100. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region

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