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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"

11756 results found.

  1. GRB 240727A: Swift detection of a burst
  2. GRB 240726A: AstroSat CZTI detection of a short burst
  3. Fermi-LAT gamma-ray observations of IceCube-240725A
  4. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  5. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  6. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  7. Fermi-LAT gamma-ray observations of IceCube-240721A
  8. Fermi trigger No 743219692: Global MASTER-Net observations report
  9. IceCube Alert 240721.68: Global MASTER-Net observations report
  10. GRB 240720B: AstroSat CZTI detection of a short burst
  11. Fermi GRB 240720A: Global MASTER-Net observations report
  12. GRB 240720A: AstroSat CZTI detection
  13. GRB 240720A: Fermi GBM observation
  14. GRB 240720A: Swift detection of a burst
  15. Swift GRB240720.02: Global MASTER-Net observations report
  16. Konus-Wind detection of GRB 240718A
  17. Fermi GRB 240718A: Global MASTER-Net observations report
  18. LAT GRB240718.27: Global MASTER-Net observations report
  19. GRB 240718A: Fermi-LAT Detection
  20. GRB 240712A: Swift-BAT refined analysis
  21. GRB 240716A: GECAM-B detection of a long burst
  22. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  23. GRB 240715A: Swift-XRT observations
  24. Konus-Wind detection of GRB 240715A
  25. IPN triangulation of GRB 240715A (short)
  26. The EP-WXT source triggered on July 14th is likely a flaring star
  27. GRB 240713A: JinShan optical upper limits
  28. GRB 240713B: AstroSat CZTI detection of a long burst
  29. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  30. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  31. EP240708a: EP-WXT detection of a fast X-ray transient
  32. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  33. Konus-Wind detection of GRB 240627A
  34. EP240703a and EP240703b: Swift/XRT upper limits
  35. EP240703a: BTA observations
  36. EP240703c: EP-WXT detection of an X-ray transient
  37. EP240703b: EP-WXT detection of a fast X-ray transient
  38. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  39. EP240702a: Swift/XRT upper limit
  40. Fermi GRB 240702A: Global MASTER-Net observations report
  41. EP240702a: EP-WXT detection of a fast X-ray transient
  42. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  43. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  44. Fermi trigger No 741356809: Global MASTER-Net observations report
  45. Fermi GRB 240629A: Global MASTER-Net observations report
  46. Fermi trigger No 741296200: Global MASTER-Net observations report
  47. GRB 240627A: NuSTAR Detection of the long GRB
  48. GRB 240615A: SAI CMO J- band observations
  49. GRB 240627A: AstroSat CZTI detection
  50. EP240625a: GRANDMA Optical Upper Limits
  51. Konus-Wind detection of GRB 240619A
  52. EP240625a: NOT optical counterpart candidate
  53. EP240625a: EP-FXT detection of the X-ray emission
  54. EP240625a: EP-WXT detection of a fast X-ray transient
  55. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  56. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  58. Fermi trigger No 740949590: Global MASTER-Net observations report
  59. EP240618a: NOT optical counterpart candidate
  60. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  62. GRB 240619C: NuSTAR automated detection of the GRB
  63. GRB 240615A: NOT optical observations
  64. GRB 240619C: AstroSat CZTI detection
  65. Fermi trigger No 740474239: Global MASTER-Net observations report
  66. EP240618a: BOOTES-6/DPRT optical upper limit
  67. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  68. Fermi trigger No 740430582: Global MASTER-Net observations report
  69. GRB240615A: 1.3m DFOT optical upper limit
  70. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  71. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  72. Konus-Wind detection of GRB 240615A (short/hard)
  73. Fermi trigger No 740166710: Global MASTER-Net observations report
  74. Konus-Wind detection of GRB 240607A
  75. Fermi GRB 240610A: Global MASTER-Net observations report
  76. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  77. Konus-Wind detection of GRB 240606B
  78. Fermi trigger No 739506569: Global MASTER-Net observations report
  79. GRB 240607A: AstroSat CZTI detection of bright long burst
  80. GRB 240606B: GECAM-B detection a long burst
  81. Fermi trigger No 739373591: Global MASTER-Net observations report
  82. GRB 240606B: Swift-XRT afterglow detection
  83. Konus-Wind detection of GRB 240603A
  84. Fermi GRB 240604A: Global MASTER-Net observations report
  85. GRB 240604A: GECAM detection of a long burst
  86. Fermi GRB 240603C: Global MASTER-Net observations report
  87. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  88. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  89. GRB 240529A: MASTER prompt OT detection
  90. GRB 240603A: GECAM detection of a short burst
  91. Fermi GRB 240602A: Global MASTER-Net observations report
  92. GRB 240529A: further SAO RAS optical observations
  93. Swift Trigger 1232465 is not a GRB
  94. GRB 240529A: 1.3m DFOT Optical observations
  95. GRB 240531A: AstroSat CZTI detection of a short burst
  96. Konus-Wind detection of GRB 240529A
  97. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  98. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  99. GRB 240529A: Skynet Optical Observations
  100. LXT 240528A: LEIA detection of a fast X-ray transient

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