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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"

14819 results found.

  1. GRB 240727C: GRBAlpha detection
  2. GRB 240730A: Swift detection of a burst
  3. GRB 240727A: Swift/UVOT detection
  4. GRB 240727A: JinShan optical upper limits
  5. GRB 240727A: Fermi GBM Final Real-time Localization
  6. GRB 240727C: AstroSat CZTI detection of a long burst
  7. GRB 240720B: GRBAlpha detection
  8. GRB 240718A: GRBAlpha detection
  9. GRB 240710B: GRBAlpha detection
  10. GRB 240627A: GRBAlpha detection
  11. GRB240529A: VIRT optical transient detection
  12. GRB 240726A: SVOM/GRM observation
  13. GRB 240727B: AstroSat CZTI detection
  14. GRB 240726B: AstroSat CZTI detection of a short burst
  15. GRB240727A: Skynet Optical Afterglow Observations
  16. GRB 240727A: TRT optical afterglow detection
  17. GRB 240727A: Swift detection of a burst
  18. GRB 240726A: AstroSat CZTI detection of a short burst
  19. GRB 240726A: Fermi GBM Final Real-time Localization
  20. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  22. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 240720B: SVOM/GRM observation
  24. GRB 240721A: Fermi GBM Final Real-time Localization
  25. GRB 240720B: AstroSat CZTI detection of a short burst
  26. GRB 240720A: AstroSat CZTI detection
  27. GRB 240720A: Swift detection of a burst
  28. Konus-Wind detection of GRB 240718A
  29. GRB 240713A: SVOM/GRM observation
  30. GRB 240718A: Fermi-LAT Detection
  31. GRB 240718A: SVOM/GRM observation
  32. GRB 240718A: Fermi GBM Final Real-time Localization
  33. GRB 240716A: GECAM-B detection of a long burst
  34. SVOM/GRM In-Flight Trigger of GRB 240716A
  35. GRB 240713A: 2.2m CAHA optical limit
  36. GRB 240715A: GECAM-C detection of a short burst
  37. Konus-Wind detection of GRB 240715A
  38. SVOM/GRM In-Flight Trigger of GRB 240715A
  39. IPN triangulation of GRB 240715A (short)
  40. EP-WXT flaring star and the optical flaring activity during its decay phase
  41. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  42. The EP-WXT source triggered on July 14th is likely a flaring star
  43. GRB 240715A: Fermi GBM Final Real-time Localization
  44. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  45. GRB 240713A: JinShan optical upper limits
  46. GRB 240713A: OHP/T120 optical upper limit
  47. GRB240713A: X-ray follow-up observation with EP-FXT
  48. GRB 240713B: AstroSat CZTI detection of a long burst
  49. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  50. EP240708a: GSP optical upper limit
  51. GRB 240712A: Swift detection of a burst
  52. GRB 240711A: Fermi GBM Final Real-time Localization
  53. GRB 240710A: Fermi GBM Final Real-time Localization
  54. EP240708a: NOT optical observations
  55. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  56. EP240708a: EP-WXT detection of a fast X-ray transient
  57. EP240703b: GSP optical upper limit
  58. GRB 240705A: Fermi GBM Final Real-time Localization
  59. Konus-Wind detection of GRB 240627A
  60. EP240703a and EP240703b: Swift/XRT upper limits
  61. EP240703a: BOOTES-3 optical upper limit
  62. EP240703a: Liverpool Telescope optical follow-up observations
  63. EP240703c: EP-WXT detection of an X-ray transient
  64. IPN triangulation of GRB 240627A
  65. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  66. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  67. EP240703b: EP-WXT detection of a fast X-ray transient
  68. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  69. EP240702a: Swift/XRT upper limit
  70. EP240703a: EP-WXT detection of a fast X-ray transient
  71. EP240702a: GSP optical upper limit
  72. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  73. GRB 240702A: Fermi GBM Final Real-time Localization
  74. EP240702a: EP-WXT detection of a fast X-ray transient
  75. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  76. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  77. GRB 240629A: Fermi GBM Final Real-time Localization
  78. IPN triangulation of GRB 240619C
  79. GRB 240627A: NuSTAR Detection of the long GRB
  80. GRB 240615A: SAI CMO J- band observations
  81. GRB 240627A: AstroSat CZTI detection
  82. EP240626a: EP-FXT detection of the X-ray emission
  83. Konus-Wind detection of GRB 240619A
  84. EP240626a: BOOTES-7 optical upper limit
  85. EP240626a: EP-WXT detection of a fast X-ray transient
  86. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  87. GRB 240625B: Fermi GBM Final Real-time Localization
  88. EP240625a: EP-FXT detection of the X-ray emission
  89. GRB 240624B: GRBAlpha detection
  90. GRB 240625A: Fermi GBM Final Real-time Localization
  91. EP240625a: EP-WXT detection of a fast X-ray transient
  92. GRB 240624B: Fermi GBM Final Real-time Localization
  93. GRB 240624A: Fermi GBM Final Real-time Localization
  94. GRB 240619A: detection of a radio counterpart with AMI-LA
  95. GRB 240624A: Swift detection of a burst
  96. LIGO/Virgo/KAGRA S240623dg: Retraction of GW compact binary merger candidate
  97. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  98. GRB 240619A: J-band detection with WINTER
  99. EP240618a: GSP optical upper limit
  100. IPN triangulation of GRB 240615A (short)

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