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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"

12091 results found.

  1. EP240801a: optical observations at CrAO and AbAO
  2. EP240801a: Leavitt Observatory optical observations
  3. GRB 240801B: AstroSat CZTI detection of a bright long burst
  4. Fermi GRB 240801A: Global MASTER-Net observations report
  5. GRB 240730C: AstroSat CZTI detection of a long burst
  6. GRB 240731A: Fermi GBM Final Localization
  7. GRB 240731A: AstroSat CZTI detection
  8. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  9. Fermi GRB 240727A: Global MASTER-Net observations report
  10. GRB 240727A: Swift/UVOT detection
  11. GRB 240727A: Correction to time in GCN36960
  12. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  13. GRB 240727A Bassano Bresciano Observatory upper limit
  14. GRB 240727C: AstroSat CZTI detection of a long burst
  15. GRB 240727A: Swift-XRT refined Analysis
  16. GRB 240720B: GRBAlpha detection
  17. Fermi GRB 240726A: Global MASTER-Net observations report
  18. GRB 240727B: AstroSat CZTI detection
  19. GRB 240726B: AstroSat CZTI detection of a short burst
  20. GRB 240727A: Swift detection of a burst
  21. GRB 240726A: AstroSat CZTI detection of a short burst
  22. Fermi-LAT gamma-ray observations of IceCube-240725A
  23. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  24. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  25. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  26. Fermi-LAT gamma-ray observations of IceCube-240721A
  27. Fermi trigger No 743219692: Global MASTER-Net observations report
  28. IceCube Alert 240721.68: Global MASTER-Net observations report
  29. GRB 240720B: AstroSat CZTI detection of a short burst
  30. Fermi GRB 240720A: Global MASTER-Net observations report
  31. GRB 240720A: AstroSat CZTI detection
  32. GRB 240720A: Fermi GBM observation
  33. GRB 240720A: Swift detection of a burst
  34. Swift GRB240720.02: Global MASTER-Net observations report
  35. Konus-Wind detection of GRB 240718A
  36. Fermi GRB 240718A: Global MASTER-Net observations report
  37. LAT GRB240718.27: Global MASTER-Net observations report
  38. GRB 240718A: Fermi-LAT Detection
  39. GRB 240712A: Swift-BAT refined analysis
  40. GRB 240716A: GECAM-B detection of a long burst
  41. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  42. GRB 240715A: Swift-XRT observations
  43. Konus-Wind detection of GRB 240715A
  44. IPN triangulation of GRB 240715A (short)
  45. The EP-WXT source triggered on July 14th is likely a flaring star
  46. GRB 240713A: JinShan optical upper limits
  47. GRB 240713B: AstroSat CZTI detection of a long burst
  48. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  49. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  50. EP240708a: EP-WXT detection of a fast X-ray transient
  51. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  52. Konus-Wind detection of GRB 240627A
  53. EP240703a and EP240703b: Swift/XRT upper limits
  54. EP240703a: BTA observations
  55. EP240703c: EP-WXT detection of an X-ray transient
  56. EP240703b: EP-WXT detection of a fast X-ray transient
  57. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  58. EP240702a: Swift/XRT upper limit
  59. Fermi GRB 240702A: Global MASTER-Net observations report
  60. EP240702a: EP-WXT detection of a fast X-ray transient
  61. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  62. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  63. Fermi trigger No 741356809: Global MASTER-Net observations report
  64. Fermi GRB 240629A: Global MASTER-Net observations report
  65. Fermi trigger No 741296200: Global MASTER-Net observations report
  66. GRB 240627A: NuSTAR Detection of the long GRB
  67. GRB 240615A: SAI CMO J- band observations
  68. GRB 240627A: AstroSat CZTI detection
  69. EP240625a: GRANDMA Optical Upper Limits
  70. Konus-Wind detection of GRB 240619A
  71. EP240625a: NOT optical counterpart candidate
  72. EP240625a: EP-FXT detection of the X-ray emission
  73. EP240625a: EP-WXT detection of a fast X-ray transient
  74. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  75. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  76. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  77. Fermi trigger No 740949590: Global MASTER-Net observations report
  78. EP240618a: NOT optical counterpart candidate
  79. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  80. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  81. GRB 240619C: NuSTAR automated detection of the GRB
  82. GRB 240615A: NOT optical observations
  83. GRB 240619C: AstroSat CZTI detection
  84. Fermi trigger No 740474239: Global MASTER-Net observations report
  85. EP240618a: BOOTES-6/DPRT optical upper limit
  86. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  87. Fermi trigger No 740430582: Global MASTER-Net observations report
  88. GRB240615A: 1.3m DFOT optical upper limit
  89. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  90. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  91. Konus-Wind detection of GRB 240615A (short/hard)
  92. Fermi trigger No 740166710: Global MASTER-Net observations report
  93. Konus-Wind detection of GRB 240607A
  94. Fermi GRB 240610A: Global MASTER-Net observations report
  95. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  96. Konus-Wind detection of GRB 240606B
  97. Fermi trigger No 739506569: Global MASTER-Net observations report
  98. GRB 240607A: AstroSat CZTI detection of bright long burst
  99. GRB 240606B: GECAM-B detection a long burst
  100. Fermi trigger No 739373591: Global MASTER-Net observations report

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