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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"

913 results found.

  1. GRB 240107A: VZLUSAT-2 detection
  2. GRB 240114A: MAXI/GSC detection
  3. GRB 240107A: AstroSat CZTI detection
  4. GRB 240107A: MAXI/GSC detection
  5. IPN triangulation of GRB 231129C
  6. GRB 231129C: ASIM MXGS observation and localization
  7. Konus-Wind detection of GRB 231129C
  8. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  9. GRB 231129B: Swift-XRT observations
  10. GRB 231129C: AGILE detection
  11. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  12. GRB 231129C: MASTER OT detection
  13. GRB 231129C: Fermi-LAT detection
  14. GRB 231129C: GRBAlpha detection
  15. GRB 231129C: Glowbug gamma-ray detection
  16. GRB 231129C: GECAM-B detection of a bright burst
  17. GRB 231129C: AstroSat CZTI detection
  18. GRB 231129C: CALET Gamma-Ray Burst Monitor detection
  19. GRB 231129C: Fermi GBM Observation of a very bright GRB
  20. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  21. GRB 231129C: MAXI/GSC detection
  22. GRB 231129B: Tiled Swift observations
  23. GRB 231129B: MAXI/GSC detection
  24. LIGO/Virgo/KAGRA S231119ab: Coverage and upper limits from MAXI/GSC observations
  25. GRB 231117A: ATLAS non-detection of an optical counterpart
  26. LIGO/Virgo/KAGRA S231113cd: Coverage and upper limits from MAXI/GSC observations
  27. LIGO/Virgo/KAGRA S231113bw: Coverage and upper limits from MAXI/GSC observations
  28. LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
  29. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  30. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  31. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  32. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  33. LIGO/Virgo/KAGRA S230917af: MAXI/GSC observations
  34. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  35. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  36. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  37. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  38. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  39. Konus-Wind detection of GRB 220623A
  40. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  41. LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
  42. GRB 230623A: Swift-XRT observations
  43. GRB 230623A: Tiled Swift observations
  44. MAXI GRB 230623A: MASTER optical observations
  45. GRB 230623A: Tiled Swift observations
  46. GRB 230623A: MAXI/GSC detection
  47. LIGO/Virgo S230603aa: Global MASTER-Net observations report
  48. LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
  49. GRB 230520A: CALET Gamma-Ray Burst Monitor detection
  50. GRB 230520A: MAXI/GSC detection
  51. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  52. LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
  53. GRB 230510B: Fermi GBM detection
  54. GRB 230510B: AstroSat CZTI detection
  55. GRB 230510B: CALET Gamma-Ray Burst Monitor detection
  56. GRB 230510B: MAXI/GSC detection
  57. GRB 230420A: Swift detection of a burst
  58. MAXI GRB230408.82: Global MASTER-Net observations report
  59. GRB 230307A: soft X-ray detection with LEIA
  60. GRB 230307A: MAXI/GSC upper limit
  61. GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate
  62. GRB 230220A: Correction to GCN 33352
  63. GRB 230220A: MAXI/GSC detection
  64. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  65. GRB 230204B: ATCA radio detection
  66. GRB 230204B: MASTER early OT detection
  67. GRB 230204B: Swift/UVOT Upper Limits
  68. GRB 230204B: Fermi GBM detection
  69. GRB 230204B: Swift-XRT afterglow detection
  70. GRB 230204B: 3.6m DOT optical observation
  71. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  72. GRB 230204B: Swift ToO observations
  73. GRB 230204B: Detection by GRBAlpha
  74. GRB 230204B: AGILE detection
  75. GRB 230204B: GIT discovery of the likely optical afterglow
  76. GRB 230204B: AstroSat CZTI detection
  77. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  78. GRB 230204B: MAXI/GSC detection
  79. IceCube Alert 230122.16: Global MASTER-Net observations report
  80. GRB 230111A: Fermi GBM Observation
  81. GRB 230111A: MAXI/GSC detection
  82. GRB 221119A: Fermi GBM detection
  83. GRB 221028B: MAXI/GSC detection
  84. Konus-Wind detection of GRB 221017A
  85. GRB 221021A: Fermi GBM observation
  86. GRB 221017A: CALET Gamma-Ray Burst Monitor detection
  87. GRB 221017A: Swift-XRT observations
  88. GRB 221017A: Swift ToO observations
  89. IPN triangulation of GRB 221017A (long)
  90. MAXI GRB221017.24: Global MASTER-Net observations report
  91. GRB 221017A: MAXI/GSC detection
  92. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  93. MAXI GRB 221006A: Redshifts of the possible host galaxies
  94. GRB 221006A: Swift-XRT afterglow detection
  95. Afterglow limits of GRB 221006A from OHP
  96. GRB 221009A: NICER follow-up observations
  97. GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
  98. GRB 221006A: Swift ToO observations
  99. GRB 221006A: CALET Gamma-Ray Burst Monitor detection
  100. Integral GRB221010.89: Global MASTER-Net observations report

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