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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"

995 results found.

  1. GRB 230828A: AstroSat CZTI detection
  2. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  3. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  4. Fermi trigger No 712713532: Global MASTER-Net observations report
  5. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  6. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  7. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  8. Konus-Wind detection of GRB 220623A
  9. LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
  10. GRB 230623A: Swift-XRT observations
  11. GRB 230623A: Tiled Swift observations
  12. MAXI GRB 230623A: MASTER optical observations
  13. GRB 230623A: Tiled Swift observations
  14. GRB 230623A: MAXI/GSC detection
  15. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  16. LIGO/Virgo/KAGRA S230518h: No transient candidates in CALET observations
  17. GRB 230520A: CALET Gamma-Ray Burst Monitor detection
  18. GRB 230520A: MAXI/GSC detection
  19. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  20. GRB 230510B: Fermi GBM detection
  21. GRB 230510B: AstroSat CZTI detection
  22. GRB 230510B: CALET Gamma-Ray Burst Monitor detection
  23. GRB 230510B: MAXI/GSC detection
  24. MAXI GRB230408.82: Global MASTER-Net observations report
  25. GRB 230307A: soft X-ray detection with LEIA
  26. GRB 230307A: MAXI/GSC upper limit
  27. GRB 230220A: Correction to GCN 33352
  28. GRB 230220A: MAXI/GSC detection
  29. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  30. GRB 230204B: ATCA radio detection
  31. GRB 230204B: MASTER early OT detection
  32. GRB 230204B: Swift/UVOT Upper Limits
  33. GRB 230204B: Fermi GBM detection
  34. GRB 230204B: Swift-XRT afterglow detection
  35. GRB 230204B: 3.6m DOT optical observation
  36. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  37. GRB 230204B: Swift ToO observations
  38. GRB 230204B: Detection by GRBAlpha
  39. GRB 230204B: AGILE detection
  40. GRB 230204B: GIT discovery of the likely optical afterglow
  41. GRB 230204B: AstroSat CZTI detection
  42. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  43. GRB 230204B: MAXI/GSC detection
  44. GRB 230111A: Fermi GBM Observation
  45. GRB 230111A: MAXI/GSC detection
  46. GRB 221028B: MAXI/GSC detection
  47. Konus-Wind detection of GRB 221017A
  48. GRB 221017A: CALET Gamma-Ray Burst Monitor detection
  49. GRB 221017A: Swift-XRT observations
  50. GRB 221017A: Swift ToO observations
  51. IPN triangulation of GRB 221017A (long)
  52. MAXI GRB221017.24: Global MASTER-Net observations report
  53. GRB 221017A: MAXI/GSC detection
  54. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  55. MAXI GRB 221006A: Redshifts of the possible host galaxies
  56. GRB 221006A: Swift-XRT afterglow detection
  57. Afterglow limits of GRB 221006A from OHP
  58. GRB 221009A: NICER follow-up observations
  59. GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
  60. GRB 221006A: Swift ToO observations
  61. GRB 221006A: CALET Gamma-Ray Burst Monitor detection
  62. GRB 221009A BOOTES-2/TELMA and OSN optical detections
  63. GRB 221008A: Swift-XRT observations
  64. GRB 221008A: Tiled Swift observations
  65. GRB 221008A: MAXI/GSC detection
  66. GRB 221006A: Swift-XRT observations
  67. GRB 221006A: Tiled Swift observations
  68. GRB 221006A: MAXI/GSC detection
  69. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  70. MAXI GRB220706.73: Global MASTER-Net observations report
  71. GRB 220701A: BOOTES-5/JGT early optical upper limit
  72. Trigger 1113743: Swift detection of MAXI J0655-013
  73. Swift Detection of MAXI J0655-013
  74. GRB 220611A: Swift detection of a burst
  75. MAXI GRB220607.31: Global MASTER-Net observations report
  76. MAXI GRB220607.41: Global MASTER-Net observations report
  77. Konus-Wind detection of GRB 220506A
  78. Konus-Wind detection of GRB 220514B
  79. GRB 220514B: Swift-XRT observations
  80. GRB 220514B: Tiled Swift observations
  81. GRB 220514B: MAXI/GSC detection
  82. MAXI GRB220514.98: Global MASTER-Net observations report
  83. GRB 220506A: MITSuME Akeno optical upper limits
  84. GRB 220506A: GIT optical upper limit.
  85. GRB 220506A: BOOTES-5/JGT optical upper limit
  86. GRB 220506A: Swift-XRT afterglow detection
  87. GRB 220506A: Tiled Swift observations
  88. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  89. MAXI GRB220506.27: Global MASTER-Net observations report
  90. GRB 220310A: MITSuME Akeno optical observation
  91. IPN triangulation of GRB 220310A
  92. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  93. Konus-Wind detection of GRB 220310A
  94. GRB 220310A: GIT confirmation of optical afterglow.
  95. GRB 220310A: MASTER optical counterpart detection
  96. GRB 220310A: Swift ToO observations
  97. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  98. GRB 220310A: MAXI/GSC detection
  99. MAXI GRB220310.02: Global MASTER-Net observations report
  100. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis

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