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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"

2853 results found.

  1. GRB 241030A: AKO Optical Afterglow Detection
  2. GRB 241026A: SAO RAS optical observations
  3. EP241021a: SAO RAS observations of rebrightening
  4. GRB 241026A: the 100th GRB detected by GRBAlpha
  5. GRB 241026A: GECAM detection
  6. GRB 241025A: further SAO RAS optical observations
  7. GRB 241026A: SVOM/GRM observation
  8. GRB 241026A Fermi GBM Analysis
  9. GRB 241026A: BTA redshift identification of z = 2.79
  10. GRB 241026A: Swift detection of a burst
  11. GRB 241026A: Fermi GBM Final Real-time Localization
  12. Fermi trigger No 751554401: Global MASTER-Net observations report
  13. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  14. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  15. Fermi trigger No 750788395: Global MASTER-Net observations report
  16. Fermi GRB 241013B: Global MASTER-Net observations report
  17. GRB 241013B: Fermi GBM Final Real-time Localization
  18. Fermi trigger No 750211959: Global MASTER-Net observations report
  19. Swift GRB 241010A: Global MASTER-Net observations report
  20. Fermi GRB 241008A: Global MASTER-Net observations report
  21. GRB 241006A: GRANDMA optical upper limits
  22. LIGO/Virgo/KAGRA S241006k: Identification of a GW compact binary merger candidate
  23. Fermi trigger No 749735279: Global MASTER-Net observations report
  24. Konus-Wind detection of GRB 240926A
  25. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  26. IPN triangulation of GRB 240926A
  27. Fermi trigger No 749339671: Global MASTER-Net observations report
  28. Fermi GRB 240929A: Global MASTER-Net observations report
  29. GRB 240926A: SVOM/GRM observation
  30. GRB 240918B: AstroSat CZTI detection
  31. EP240919a / GRB 240919A: Mondy optical upper limit
  32. EP240918b and EP240918c: Optical upper limits with Kinder observations
  33. GRB 240910A: radio detection with the VLA
  34. IPN triangulation of GRB 240913C / EP 240913a
  35. GRB 240913C: Fermi GBM detection
  36. GRB 240913C: Joint location by ETJASMIN
  37. GRB 240914B: AstroSat CZTI detection
  38. EP240913A / GRB 240913C: AstroSat CZTI detection
  39. GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
  40. GRB 240912A: Swift detection of a burst with an optical counterpart
  41. GRB 240825A: 7DT Optical Upper Limit
  42. GRB 240910B: Fermi GBM Final Real-time Localization
  43. Fermi GRB 240908A: Global MASTER-Net observations report
  44. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  45. GRB 240902B: AstroSat CZTI detection of a long burst
  46. GRB 240902A: AstroSat CZTI detection of a long burst
  47. GRB 240905E: Swift detection of a burst
  48. GRB 240905D: AstroSat CZTI detection
  49. GRB 240905B: AstroSat CZTI detection and localization
  50. Fermi trigger No 746923430: Global MASTER-Net observations report
  51. GRB 240828B: AbAO optical upper limit
  52. GRB 240828B: Swift-XRT afterglow detection
  53. GRB 240828A: AstroSat CZTI detection of a long burst
  54. GRB 240825A: AstroSat CZTI detection of the long bright burst
  55. GRB 240825A: GMG Optical Observation
  56. GRB 240822A: AstroSat CZTI detection of a short burst
  57. GRB 240821A: Fermi GBM Observation
  58. Fermi trigger No 746019401: Global MASTER-Net observations report
  59. Fermi trigger No 745935375: Global MASTER-Net observations report
  60. Fermi trigger No 745866488: Global MASTER-Net observations report
  61. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  62. EP240816b: KAIT optical upper limit
  63. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  64. Fermi GRB 240814C: Global MASTER-Net observations report
  65. Fermi GRB 240814B: Global MASTER-Net observations report
  66. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  67. GRB 240812B: AstroSat CZTI detection of a long burst
  68. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  69. GRB 240808A: AstroSat CZTI detection
  70. IPN triangulation of GRB 240807A / EP 240807a
  71. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  72. GRB 240807A: SVOM/GRM observation
  73. GRB 240807B: AstroSat CZTI detection of a short burst
  74. EP EP240807a: Global MASTER-Net observations report
  75. EP EP240806a: Global MASTER-Net observations report
  76. GRB 240807B: Fermi GBM Final Localization
  77. GRB 240805A: ATCA Radio Upper Limits
  78. Fermi trigger No 744761058: Global MASTER-Net observations report
  79. GRB 240807A: Fermi GBM Final Localization
  80. EP240807a: EP-WXT detection of a fast X-ray transient
  81. Fermi trigger No 744629911: Global MASTER-Net observations report
  82. Konus-Wind detection of GRB 240802A (EP240802a)
  83. Fermi trigger No 744544656: Global MASTER-Net observations report
  84. Fermi GRB 240805A: Global MASTER-Net observations report
  85. GRB 240802A: AstroSat CZTI detection of a long burst
  86. GRB 240801B: AstroSat CZTI detection of a bright long burst
  87. GRB 240730C: AstroSat CZTI detection of a long burst
  88. Fermi trigger No 744128417: Global MASTER-Net observations report
  89. GRB 240731A: AstroSat CZTI detection
  90. Fermi trigger No 743953682: Global MASTER-Net observations report
  91. Fermi GRB 240727A: Global MASTER-Net observations report
  92. GRB 240727C: AstroSat CZTI detection of a long burst
  93. GRB 240727B: AstroSat CZTI detection
  94. GRB 240726B: AstroSat CZTI detection of a short burst
  95. GRB 240726A: AstroSat CZTI detection of a short burst
  96. Fermi trigger No 743219692: Global MASTER-Net observations report
  97. IceCube Alert 240721.68: Global MASTER-Net observations report
  98. GRB 240720B: AstroSat CZTI detection of a short burst
  99. GRB 240720A: AstroSat CZTI detection
  100. Fermi GRB 240718A: Global MASTER-Net observations report

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