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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"

3029 results found.

  1. GRB 241010A: LCO optical observations
  2. Fermi GRB 241008A: Global MASTER-Net observations report
  3. IceCube-241006A: No candidates from the Zwicky Transient Facility
  4. IceCube Alert 241006.94: Global MASTER-Net observations report
  5. GRB 241006A: Swift detection of a burst
  6. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  7. Fermi trigger No 749693019: Global MASTER-Net observations report
  8. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  9. GRB 241002A: 1.5m OSN optical upper limit
  10. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  11. Fermi GRB 240930B: Global MASTER-Net observations report
  12. GRB 240930B: Fermi GBM Final Real-time Localization
  13. Fermi GRB 240930A: Global MASTER-Net observations report
  14. Fermi GRB 240929A: Global MASTER-Net observations report
  15. Konus-Wind detection of GRB 240912A
  16. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  17. EP trigger ID 01709059262: correction to the observation start time and source localization
  18. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  19. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  20. GRB 240919A / EP240919a: SVOM/GRM observation
  21. EP240919a: NOT and Gemini optical observations
  22. EP240919a is likely a GRB event
  23. EP240919a: EP-WXT detection of a fast X-ray transient
  24. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  25. EP EP240918a: Global MASTER-Net observations report
  26. GRB 240914B: AstroSat CZTI detection
  27. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  28. GRB 240914B: BALROG localization (Fermi Trigger 747990592 / GRB 240914298)
  29. GRB 240912A: SVOM/GRM observation
  30. GRB 240825A: 7DT Optical Upper Limit
  31. GRB 240902B: AstroSat CZTI detection of a long burst
  32. GRB 240825A: Montarrenti Observatory optical follow-up observations
  33. Fermi trigger No 746923430: Global MASTER-Net observations report
  34. GRB 240828B: SVOM/C-GFT optical upper limit
  35. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  36. Fermi trigger No 746438824: Global MASTER-Net observations report
  37. GRB 240828A: Fermi GBM Final Real-time Localization
  38. Swift GRB240824.04: Global MASTER-Net observations report
  39. GRB 240822A: AstroSat CZTI detection of a short burst
  40. Fermi trigger No 746019401: Global MASTER-Net observations report
  41. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  42. Fermi trigger No 745935375: Global MASTER-Net observations report
  43. Fermi trigger No 745866488: Global MASTER-Net observations report
  44. EP240820a: EP detection of a fast X-ray transient
  45. GRB 240817A: Fermi GBM Final Real-time Localization
  46. EP EP240816b: Global MASTER-Net observations report
  47. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  48. Fermi GRB 240814B: Global MASTER-Net observations report
  49. EP EP240807a: Global MASTER-Net observations report
  50. EP EP240806a: Global MASTER-Net observations report
  51. EP240806A: Liverpool Telescope optical follow-up observations
  52. Fermi trigger No 744629911: Global MASTER-Net observations report
  53. Konus-Wind detection of GRB 240802A (EP240802a)
  54. EP240806a: EP-WXT detection of a fast X-ray transient
  55. EP240801a: BTA BVRI photometry
  56. Fermi GRB 240805A: Global MASTER-Net observations report
  57. Swift GRB 240805A: Global MASTER-Net observations report
  58. GRB 240804A: Fermi GBM Final Real-time Localization
  59. Fermi trigger No 744128417: Global MASTER-Net observations report
  60. Fermi trigger No 743953682: Global MASTER-Net observations report
  61. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  62. GRB 240726A: Fermi GBM Final Real-time Localization
  63. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  64. Fermi trigger No 743418632: Global MASTER-Net observations report
  65. Fermi trigger No 743219692: Global MASTER-Net observations report
  66. IceCube Alert 240721.68: Global MASTER-Net observations report
  67. Fermi GRB 240720A: Global MASTER-Net observations report
  68. GRB 240720A: Fermi GBM observation
  69. Fermi GRB 240718A: Global MASTER-Net observations report
  70. Konus-Wind detection of GRB 240715A
  71. GRB 240715A: Fermi GBM Observation
  72. GRB 240712A: Swift detection of a burst
  73. Fermi trigger No 742317942: Global MASTER-Net observations report
  74. GRB 240710A: Fermi GBM Final Real-time Localization
  75. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  76. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  77. GRB 240627A: AstroSat CZTI detection
  78. Fermi trigger No 741211696: Global MASTER-Net observations report
  79. GRB 240619B: Fermi GBM Final Real-time Localization
  80. Fermi trigger No 740430582: Global MASTER-Net observations report
  81. Fermi GRB 240616A: Global MASTER-Net observations report
  82. Fermi trigger No 740166710: Global MASTER-Net observations report
  83. Fermi GRB 240610A: Global MASTER-Net observations report
  84. Fermi GRB 240607A: Global MASTER-Net observations report
  85. GRB 240529A: SAO RAS optical observations
  86. Fermi GRB 240603C: Global MASTER-Net observations report
  87. GRB 240603C: Fermi GBM Final Real-time Localization
  88. GRB 240529A: continued SAO RAS optical observations
  89. Fermi GRB 240602A: Global MASTER-Net observations report
  90. GRB 240529A: J-band detections with WINTER
  91. GRB 240529A: NOT optical observations
  92. GRB 240523A: Swift-BAT refined analysis
  93. Fermi trigger No 738348224: Global MASTER-Net observations report
  94. GRB 240523A: Swift detection of a burst
  95. Fermi trigger No 737996942: Global MASTER-Net observations report
  96. Fermi GRB 240517A: Global MASTER-Net observations report
  97. GRB 240516A: Fermi GBM Observation
  98. Fermi trigger No 737523389: Global MASTER-Net observations report
  99. MAXI GRB240514.78: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate

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