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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"

14823 results found.

  1. GRB 240731A: AstroSat CZTI detection
  2. GRB240730A: BOOTES-5/JGT early optical upper limit
  3. GRB 240730B: Fermi GBM Final Real-time Localization
  4. GRB 240715A: Swift-XRT afterglow detection
  5. GRB 240727C: GRBAlpha detection
  6. GRB 240730A: Swift detection of a burst
  7. GRB 240727A: Swift/UVOT detection
  8. GRB 240727A: JinShan optical upper limits
  9. GRB 240727A: Fermi GBM Final Real-time Localization
  10. GRB 240727C: AstroSat CZTI detection of a long burst
  11. GRB 240720B: GRBAlpha detection
  12. GRB 240718A: GRBAlpha detection
  13. GRB 240710B: GRBAlpha detection
  14. GRB 240627A: GRBAlpha detection
  15. GRB240529A: VIRT optical transient detection
  16. GRB 240726A: SVOM/GRM observation
  17. GRB 240727B: AstroSat CZTI detection
  18. GRB 240726B: AstroSat CZTI detection of a short burst
  19. GRB240727A: Skynet Optical Afterglow Observations
  20. GRB 240727A: TRT optical afterglow detection
  21. GRB 240727A: Swift detection of a burst
  22. GRB 240726A: AstroSat CZTI detection of a short burst
  23. GRB 240726A: Fermi GBM Final Real-time Localization
  24. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  25. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  26. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  27. GRB 240720B: SVOM/GRM observation
  28. GRB 240721A: Fermi GBM Final Real-time Localization
  29. GRB 240720B: AstroSat CZTI detection of a short burst
  30. GRB 240720A: AstroSat CZTI detection
  31. GRB 240720A: Swift detection of a burst
  32. Konus-Wind detection of GRB 240718A
  33. GRB 240713A: SVOM/GRM observation
  34. GRB 240718A: Fermi-LAT Detection
  35. GRB 240718A: SVOM/GRM observation
  36. GRB 240718A: Fermi GBM Final Real-time Localization
  37. GRB 240716A: GECAM-B detection of a long burst
  38. SVOM/GRM In-Flight Trigger of GRB 240716A
  39. GRB 240713A: 2.2m CAHA optical limit
  40. GRB 240715A: GECAM-C detection of a short burst
  41. Konus-Wind detection of GRB 240715A
  42. SVOM/GRM In-Flight Trigger of GRB 240715A
  43. IPN triangulation of GRB 240715A (short)
  44. EP-WXT flaring star and the optical flaring activity during its decay phase
  45. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  46. The EP-WXT source triggered on July 14th is likely a flaring star
  47. GRB 240715A: Fermi GBM Final Real-time Localization
  48. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  49. GRB 240713A: JinShan optical upper limits
  50. GRB 240713A: OHP/T120 optical upper limit
  51. GRB240713A: X-ray follow-up observation with EP-FXT
  52. GRB 240713B: AstroSat CZTI detection of a long burst
  53. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  54. EP240708a: GSP optical upper limit
  55. GRB 240712A: Swift detection of a burst
  56. GRB 240711A: Fermi GBM Final Real-time Localization
  57. GRB 240710A: Fermi GBM Final Real-time Localization
  58. EP240708a: NOT optical observations
  59. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  60. EP240708a: EP-WXT detection of a fast X-ray transient
  61. EP240703b: GSP optical upper limit
  62. GRB 240705A: Fermi GBM Final Real-time Localization
  63. Konus-Wind detection of GRB 240627A
  64. EP240703a and EP240703b: Swift/XRT upper limits
  65. EP240703a: BOOTES-3 optical upper limit
  66. EP240703a: Liverpool Telescope optical follow-up observations
  67. EP240703c: EP-WXT detection of an X-ray transient
  68. IPN triangulation of GRB 240627A
  69. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  70. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  71. EP240703b: EP-WXT detection of a fast X-ray transient
  72. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  73. EP240702a: Swift/XRT upper limit
  74. EP240703a: EP-WXT detection of a fast X-ray transient
  75. EP240702a: GSP optical upper limit
  76. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  77. GRB 240702A: Fermi GBM Final Real-time Localization
  78. EP240702a: EP-WXT detection of a fast X-ray transient
  79. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  80. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  81. GRB 240629A: Fermi GBM Final Real-time Localization
  82. IPN triangulation of GRB 240619C
  83. GRB 240627A: NuSTAR Detection of the long GRB
  84. GRB 240615A: SAI CMO J- band observations
  85. GRB 240627A: AstroSat CZTI detection
  86. EP240626a: EP-FXT detection of the X-ray emission
  87. Konus-Wind detection of GRB 240619A
  88. EP240626a: BOOTES-7 optical upper limit
  89. EP240626a: EP-WXT detection of a fast X-ray transient
  90. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  91. GRB 240625B: Fermi GBM Final Real-time Localization
  92. EP240625a: EP-FXT detection of the X-ray emission
  93. GRB 240624B: GRBAlpha detection
  94. GRB 240625A: Fermi GBM Final Real-time Localization
  95. EP240625a: EP-WXT detection of a fast X-ray transient
  96. GRB 240624B: Fermi GBM Final Real-time Localization
  97. GRB 240624A: Fermi GBM Final Real-time Localization
  98. GRB 240619A: detection of a radio counterpart with AMI-LA
  99. GRB 240624A: Swift detection of a burst
  100. LIGO/Virgo/KAGRA S240623dg: Retraction of GW compact binary merger candidate

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