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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"

966 results found.

  1. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  2. GRB 230520A: CALET Gamma-Ray Burst Monitor detection
  3. GRB 230520A: MAXI/GSC detection
  4. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  5. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  6. GRB 230510B: Fermi GBM detection
  7. GRB 230510B: AstroSat CZTI detection
  8. GRB 230510B: CALET Gamma-Ray Burst Monitor detection
  9. GRB 230510B: MAXI/GSC detection
  10. GRB 230420A: Swift detection of a burst
  11. MAXI GRB230408.82: Global MASTER-Net observations report
  12. GRB 230307A: soft X-ray detection with LEIA
  13. GRB 230307A: MAXI/GSC upper limit
  14. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  15. GRB 230220A: Correction to GCN 33352
  16. GRB 230220A: MAXI/GSC detection
  17. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  18. GRB 230204B: ATCA radio detection
  19. GRB 230204B: MASTER early OT detection
  20. GRB 230204B: Swift/UVOT Upper Limits
  21. GRB 230204B: Fermi GBM detection
  22. GRB 230204B: Swift-XRT afterglow detection
  23. GRB 230204B: 3.6m DOT optical observation
  24. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  25. GRB 230204B: Swift ToO observations
  26. GRB 230204B: Detection by GRBAlpha
  27. GRB 230204B: AGILE detection
  28. GRB 230204B: GIT discovery of the likely optical afterglow
  29. GRB 230204B: AstroSat CZTI detection
  30. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  31. GRB 230204B: MAXI/GSC detection
  32. IceCube Alert 230122.16: Global MASTER-Net observations report
  33. GRB 230111A: Fermi GBM Observation
  34. GRB 230111A: MAXI/GSC detection
  35. GRB 221119A: Fermi GBM detection
  36. GRB 221028B: MAXI/GSC detection
  37. Konus-Wind detection of GRB 221017A
  38. GRB 221021A: Fermi GBM observation
  39. GRB 221017A: CALET Gamma-Ray Burst Monitor detection
  40. GRB 221017A: Swift-XRT observations
  41. GRB 221017A: Swift ToO observations
  42. IPN triangulation of GRB 221017A (long)
  43. MAXI GRB221017.24: Global MASTER-Net observations report
  44. GRB 221017A: MAXI/GSC detection
  45. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  46. MAXI GRB 221006A: Redshifts of the possible host galaxies
  47. GRB 221006A: Swift-XRT afterglow detection
  48. Afterglow limits of GRB 221006A from OHP
  49. GRB 221009A: NICER follow-up observations
  50. GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
  51. GRB 221006A: Swift ToO observations
  52. GRB 221006A: CALET Gamma-Ray Burst Monitor detection
  53. Integral GRB221010.89: Global MASTER-Net observations report
  54. GRB 221009A BOOTES-2/TELMA and OSN optical detections
  55. GRB 221008A: Swift-XRT observations
  56. GRB 221008A: Tiled Swift observations
  57. GRB 221008A: MAXI/GSC detection
  58. GRB 221006A: Swift-XRT observations
  59. GRB 221006A: Tiled Swift observations
  60. GRB 221006A: MAXI/GSC detection
  61. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  62. MAXI GRB220706.73: Global MASTER-Net observations report
  63. Trigger 1113743: Swift detection of MAXI J0655-013
  64. GRB 220624A: Fermi GBM Detection
  65. Swift Detection of MAXI J0655-013
  66. MAXI GRB220607.31: Global MASTER-Net observations report
  67. MAXI GRB220607.41: Global MASTER-Net observations report
  68. Konus-Wind detection of GRB 220506A
  69. Konus-Wind detection of GRB 220514B
  70. GRB 220514B: Swift-XRT observations
  71. GRB 220514B: Tiled Swift observations
  72. GRB 220514B: MAXI/GSC detection
  73. MAXI GRB220514.98: Global MASTER-Net observations report
  74. GRB 220506A: MITSuME Akeno optical upper limits
  75. GRB 220506A: GIT optical upper limit.
  76. GRB 220506A: BOOTES-5/JGT optical upper limit
  77. GRB 220506A: Swift-XRT afterglow detection
  78. GRB 220506A: Tiled Swift observations
  79. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  80. MAXI GRB220506.27: Global MASTER-Net observations report
  81. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
  82. GRB 220310A: MITSuME Akeno optical observation
  83. IPN triangulation of GRB 220310A
  84. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  85. Konus-Wind detection of GRB 220310A
  86. GRB 220310A: GIT confirmation of optical afterglow.
  87. GRB 220310A: MASTER optical counterpart detection
  88. GRB 220310A: Swift ToO observations
  89. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  90. GRB 220310A: MAXI/GSC detection
  91. MAXI GRB220310.02: Global MASTER-Net observations report
  92. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  93. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  94. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  95. GRB 211227A: MAXI/GSC detection
  96. GRB 211225A: MITSuME Akeno optical upper limits
  97. MAXI GRB211225.14: Global MASTER-Net observations report
  98. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  99. GRB 211218A: MITSuME Akeno optical upper limits
  100. GRB 211218A, MAXI J0909-041: MAXI/GSC detection

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