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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"

2722 results found.

  1. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  2. GRB 241002A: 1.5m OSN optical upper limit
  3. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  4. Fermi GRB 240930B: Global MASTER-Net observations report
  5. GRB 240930B: Fermi GBM Final Real-time Localization
  6. Fermi GRB 240930A: Global MASTER-Net observations report
  7. Fermi GRB 240929A: Global MASTER-Net observations report
  8. Konus-Wind detection of GRB 240912A
  9. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  10. EP trigger ID 01709059262: correction to the observation start time and source localization
  11. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  12. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  13. GRB 240919A / EP240919a: SVOM/GRM observation
  14. EP240919a: NOT and Gemini optical observations
  15. EP240919a is likely a GRB event
  16. EP240919a: EP-WXT detection of a fast X-ray transient
  17. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  18. EP EP240918a: Global MASTER-Net observations report
  19. GRB 240914B: AstroSat CZTI detection
  20. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  21. GRB 240914B: BALROG localization (Fermi Trigger 747990592 / GRB 240914298)
  22. GRB 240912A: SVOM/GRM observation
  23. GRB 240825A: 7DT Optical Upper Limit
  24. GRB 240902B: AstroSat CZTI detection of a long burst
  25. GRB 240825A: Montarrenti Observatory optical follow-up observations
  26. Fermi trigger No 746923430: Global MASTER-Net observations report
  27. GRB 240828B: SVOM/C-GFT optical upper limit
  28. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  29. Fermi trigger No 746438824: Global MASTER-Net observations report
  30. GRB 240828A: Fermi GBM Final Real-time Localization
  31. Swift GRB240824.04: Global MASTER-Net observations report
  32. GRB 240822A: AstroSat CZTI detection of a short burst
  33. Fermi trigger No 746019401: Global MASTER-Net observations report
  34. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  35. Fermi trigger No 745935375: Global MASTER-Net observations report
  36. Fermi trigger No 745866488: Global MASTER-Net observations report
  37. EP240820a: EP detection of a fast X-ray transient
  38. GRB 240817A: Fermi GBM Final Real-time Localization
  39. EP EP240816b: Global MASTER-Net observations report
  40. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  41. Fermi GRB 240814B: Global MASTER-Net observations report
  42. EP EP240807a: Global MASTER-Net observations report
  43. EP EP240806a: Global MASTER-Net observations report
  44. EP240806A: Liverpool Telescope optical follow-up observations
  45. Fermi trigger No 744629911: Global MASTER-Net observations report
  46. Konus-Wind detection of GRB 240802A (EP240802a)
  47. EP240806a: EP-WXT detection of a fast X-ray transient
  48. EP240801a: BTA BVRI photometry
  49. Fermi GRB 240805A: Global MASTER-Net observations report
  50. Swift GRB 240805A: Global MASTER-Net observations report
  51. GRB 240804A: Fermi GBM Final Real-time Localization
  52. Fermi trigger No 744128417: Global MASTER-Net observations report
  53. Fermi trigger No 743953682: Global MASTER-Net observations report
  54. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  55. GRB 240726A: Fermi GBM Final Real-time Localization
  56. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  57. Fermi trigger No 743418632: Global MASTER-Net observations report
  58. Fermi trigger No 743219692: Global MASTER-Net observations report
  59. IceCube Alert 240721.68: Global MASTER-Net observations report
  60. Fermi GRB 240720A: Global MASTER-Net observations report
  61. GRB 240720A: Fermi GBM observation
  62. Fermi GRB 240718A: Global MASTER-Net observations report
  63. Konus-Wind detection of GRB 240715A
  64. GRB 240715A: Fermi GBM Observation
  65. GRB 240712A: Swift detection of a burst
  66. Fermi trigger No 742317942: Global MASTER-Net observations report
  67. GRB 240710A: Fermi GBM Final Real-time Localization
  68. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  69. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  70. GRB 240627A: AstroSat CZTI detection
  71. Fermi trigger No 741211696: Global MASTER-Net observations report
  72. GRB 240619B: Fermi GBM Final Real-time Localization
  73. Fermi trigger No 740430582: Global MASTER-Net observations report
  74. Fermi GRB 240616A: Global MASTER-Net observations report
  75. Fermi trigger No 740166710: Global MASTER-Net observations report
  76. Fermi GRB 240610A: Global MASTER-Net observations report
  77. Fermi GRB 240607A: Global MASTER-Net observations report
  78. GRB 240529A: SAO RAS optical observations
  79. Fermi GRB 240603C: Global MASTER-Net observations report
  80. GRB 240603C: Fermi GBM Final Real-time Localization
  81. GRB 240529A: continued SAO RAS optical observations
  82. Fermi GRB 240602A: Global MASTER-Net observations report
  83. GRB 240529A: J-band detections with WINTER
  84. GRB 240529A: NOT optical observations
  85. GRB 240523A: Swift-BAT refined analysis
  86. Fermi trigger No 738348224: Global MASTER-Net observations report
  87. GRB 240523A: Swift detection of a burst
  88. Fermi trigger No 737996942: Global MASTER-Net observations report
  89. Fermi GRB 240517A: Global MASTER-Net observations report
  90. GRB 240516A: Fermi GBM Observation
  91. Fermi trigger No 737523389: Global MASTER-Net observations report
  92. MAXI GRB240514.78: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  94. Fermi Gamma-ray Burst Monitor triggers 737345659/240514093 and GRB240514A are not GRBs
  95. GRB 240514A: Fermi GBM Final Real-time Localization
  96. LAT GRB240513.31: Global MASTER-Net observations report
  97. Fermi GRB 240513B: Global MASTER-Net observations report
  98. GRB 240513B: Fermi GBM Final Real-time Localization
  99. Fermi trigger No 737247400: Global MASTER-Net observations report
  100. Fermi trigger No 737196587: Global MASTER-Net observations report

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