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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"

2908 results found.

  1. GRB 240825A: 7DT Optical Upper Limit
  2. GRB 240902B: AstroSat CZTI detection of a long burst
  3. GRB 240825A: Montarrenti Observatory optical follow-up observations
  4. Fermi trigger No 746923430: Global MASTER-Net observations report
  5. GRB 240828B: SVOM/C-GFT optical upper limit
  6. Fermi GRB 240828A: Bassano Bresciano Observatory upper limit
  7. Fermi trigger No 746438824: Global MASTER-Net observations report
  8. GRB 240828A: Fermi GBM Final Real-time Localization
  9. Swift GRB240824.04: Global MASTER-Net observations report
  10. GRB 240822A: AstroSat CZTI detection of a short burst
  11. Fermi trigger No 746019401: Global MASTER-Net observations report
  12. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  13. Fermi trigger No 745935375: Global MASTER-Net observations report
  14. Fermi trigger No 745866488: Global MASTER-Net observations report
  15. EP240820a: EP detection of a fast X-ray transient
  16. Fermi trigger No 745871958: Global MASTER-Net observations report
  17. GRB 240817A: Fermi GBM Final Real-time Localization
  18. EP EP240816b: Global MASTER-Net observations report
  19. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  20. Fermi GRB 240814B: Global MASTER-Net observations report
  21. EP EP240807a: Global MASTER-Net observations report
  22. EP EP240806a: Global MASTER-Net observations report
  23. EP240806A: Liverpool Telescope optical follow-up observations
  24. Fermi trigger No 744629911: Global MASTER-Net observations report
  25. Konus-Wind detection of GRB 240802A (EP240802a)
  26. EP240806a: EP-WXT detection of a fast X-ray transient
  27. EP240801a: BTA BVRI photometry
  28. Fermi GRB 240805A: Global MASTER-Net observations report
  29. Swift GRB 240805A: Global MASTER-Net observations report
  30. GRB 240804A: Fermi GBM Final Real-time Localization
  31. Fermi trigger No 744128417: Global MASTER-Net observations report
  32. Fermi trigger No 743953682: Global MASTER-Net observations report
  33. Fermi Gamma-ray Burst Monitor trigger 743953682/240729575 is not a GRB
  34. GRB 240726A: Fermi GBM Final Real-time Localization
  35. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  36. Fermi trigger No 743418632: Global MASTER-Net observations report
  37. Fermi trigger No 743219692: Global MASTER-Net observations report
  38. IceCube Alert 240721.68: Global MASTER-Net observations report
  39. Fermi GRB 240720A: Global MASTER-Net observations report
  40. GRB 240720A: Fermi GBM observation
  41. Fermi GRB 240718A: Global MASTER-Net observations report
  42. Konus-Wind detection of GRB 240715A
  43. GRB 240715A: Fermi GBM Observation
  44. GRB 240713B: AstroSat CZTI detection of a long burst
  45. GRB 240712A: Swift detection of a burst
  46. Fermi trigger No 742317942: Global MASTER-Net observations report
  47. GRB 240710A: Fermi GBM Final Real-time Localization
  48. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  49. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  50. GRB 240627A: AstroSat CZTI detection
  51. Fermi trigger No 741211696: Global MASTER-Net observations report
  52. GRB 240619B: Fermi GBM Final Real-time Localization
  53. Fermi trigger No 740430582: Global MASTER-Net observations report
  54. Fermi GRB 240616A: Global MASTER-Net observations report
  55. Fermi trigger No 740166710: Global MASTER-Net observations report
  56. Fermi GRB 240610A: Global MASTER-Net observations report
  57. Fermi GRB 240607A: Global MASTER-Net observations report
  58. GRB 240529A: SAO RAS optical observations
  59. Fermi GRB 240603C: Global MASTER-Net observations report
  60. GRB 240603C: Fermi GBM Final Real-time Localization
  61. GRB 240529A: continued SAO RAS optical observations
  62. Fermi GRB 240602A: Global MASTER-Net observations report
  63. GRB 240529A: J-band detections with WINTER
  64. GRB 240529A: NOT optical observations
  65. GRB 240523A: Swift-BAT refined analysis
  66. Fermi trigger No 738348224: Global MASTER-Net observations report
  67. GRB 240523A: Swift detection of a burst
  68. Fermi trigger No 737996942: Global MASTER-Net observations report
  69. Fermi GRB 240517A: Global MASTER-Net observations report
  70. GRB 240516A: Fermi GBM Observation
  71. Fermi trigger No 737523389: Global MASTER-Net observations report
  72. MAXI GRB240514.78: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  74. Fermi Gamma-ray Burst Monitor triggers 737345659/240514093 and GRB240514A are not GRBs
  75. GRB 240514A: Fermi GBM Final Real-time Localization
  76. LAT GRB240513.31: Global MASTER-Net observations report
  77. Fermi GRB 240513B: Global MASTER-Net observations report
  78. GRB 240513B: Fermi GBM Final Real-time Localization
  79. Fermi trigger No 737247400: Global MASTER-Net observations report
  80. Fermi trigger No 737196587: Global MASTER-Net observations report
  81. Fermi trigger No 737168073: Global MASTER-Net observations report
  82. Fermi trigger No 737105243: Global MASTER-Net observations report
  83. GRB 240511A: Fermi GBM Final Real-time Localization
  84. Fermi trigger No 737111207: Global MASTER-Net observations report
  85. IPN triangulation of GRB 240504A
  86. Fermi trigger No 736564880: Global MASTER-Net observations report
  87. GRB 240503A: AstroSat CZTI detection
  88. Fermi trigger No 736387941: Global MASTER-Net observations report
  89. Fermi GRB 240501A: Global MASTER-Net observations report
  90. Fermi trigger No 736197684: Global MASTER-Net observations report
  91. GRB 240501B: AstroSat CZTI detection
  92. GRB 240426A: AstroSat CZTI detection
  93. EP240426a: YAHPT optical upper limit
  94. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  95. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  96. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  97. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  98. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  99. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  100. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search

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