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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"

27776 results found.

  1. GRB240713A: X-ray follow-up observation with EP-FXT
  2. GRB 240713B: AstroSat CZTI detection of a long burst
  3. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  4. EP240708a: GSP optical upper limit
  5. GRB 240712A: Swift detection of a burst
  6. GRB 240711A: Fermi GBM Final Real-time Localization
  7. GRB 240710A: Fermi GBM Final Real-time Localization
  8. EP240708a: NOT optical observations
  9. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  10. EP240708a: EP-WXT detection of a fast X-ray transient
  11. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  12. EP240703b: GSP optical upper limit
  13. GRB 240705A: Fermi GBM Final Real-time Localization
  14. Konus-Wind detection of GRB 240627A
  15. IPN triangulation of GRB 240628B (short)
  16. EP240703a and EP240703b: Swift/XRT upper limits
  17. EP240703c: Kinder optical follow-up and Swift XRT observations
  18. EP240703a: BOOTES-3 optical upper limit
  19. EP240703a: Liverpool Telescope optical follow-up observations
  20. EP240703c: EP-WXT detection of an X-ray transient
  21. IPN triangulation of GRB 240627A
  22. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  23. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  24. EP240703b: EP-WXT detection of a fast X-ray transient
  25. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  26. EP240702a: Swift/XRT upper limit
  27. EP240703a: EP-WXT detection of a fast X-ray transient
  28. EP240702a: GSP optical upper limit
  29. GRB 240702A: Fermi GBM Final Real-time Localization
  30. EP240702a: EP-WXT detection of a fast X-ray transient
  31. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  32. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  33. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  34. GRB 240629A: Fermi GBM Final Real-time Localization
  35. IPN triangulation of GRB 240619C
  36. GRB 240627A: NuSTAR Detection of the long GRB
  37. GRB 240615A: SAI CMO J- band observations
  38. GRB 240627A: AstroSat CZTI detection
  39. EP240626a: EP-FXT detection of the X-ray emission
  40. GRB 240624A: Swift-BAT refined analysis
  41. Konus-Wind detection of GRB 240619A
  42. EP240626a: BOOTES-7 optical upper limit
  43. EP240626a: EP-WXT detection of a fast X-ray transient
  44. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  45. GRB 240625B: Fermi GBM Final Real-time Localization
  46. EP240625a: EP-FXT detection of the X-ray emission
  47. GRB 240624B: GRBAlpha detection
  48. GRB 240625A: Fermi GBM Final Real-time Localization
  49. EP240625a: EP-WXT detection of a fast X-ray transient
  50. GRB240624A: Fermi GBM Observation
  51. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  52. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  53. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  54. Swift GRB 240624A: Global MASTER-Net observations report
  55. GRB 240624B: Fermi GBM Final Real-time Localization
  56. GRB 240624A: Fermi GBM Final Real-time Localization
  57. GRB 240619A: detection of a radio counterpart with AMI-LA
  58. GRB 240624A: Swift detection of a burst
  59. LIGO/Virgo/KAGRA S240623dg: Retraction of GW compact binary merger candidate
  60. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  61. GRB 240619A: J-band detection with WINTER
  62. GRB 240529A: JinShan optical observations
  63. EP240618a: GSP optical upper limit
  64. IPN triangulation of GRB 240615A (short)
  65. X-ray transient EP240618a: Fermi/GBM non-detection
  66. GRB 240619A: GRBAlpha detection
  67. EP240618a: Swift/XRT upper limit
  68. EP240617a: tentative Swift/XRT detection of the afterglow
  69. GRB 240619A: Swift-XRT probable afterglow detection
  70. GRB 240619A: Swift ToO observations
  71. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  72. GRB 240619C: NuSTAR automated detection of the GRB
  73. Fermi GBM Sub-Threshold Detection of GRB 240619C
  74. GRB 240619A: GOTO candidate optical afterglow
  75. GRB 240615A: NOT optical observations
  76. GRB 240619C: AstroSat CZTI detection
  77. GRB 240615A: possible transient detection from Wendelstein observations
  78. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  79. EP240618a: BOOTES-6/DPRT optical upper limit
  80. GRB 240619B: Fermi GBM Final Real-time Localization
  81. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  82. GRB240615A: 1.3m DFOT optical upper limit
  83. GRB 240619A: Fermi GBM Final Real-time Localization
  84. EP240617a: BOOTES-6/DPRT optical upper limit
  85. EP240617a is likely a GRB event
  86. EP240617a: EP-WXT detection of a fast X-ray transient
  87. EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
  88. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  89. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  90. GRB 240615A: J-band upper limits from WINTER
  91. GRB 240615A: Fermi GBM Observation
  92. GRB 240615A: Swift-XRT observations
  93. GRB 240615A: GECAM detection
  94. GRB 240615A: FLWO-1.2m optical upper limits
  95. Konus-Wind detection of GRB 240615A (short/hard)
  96. GRB 240615A: GOTO optical upper limits
  97. GRB 240616A: Fermi GBM Final Real-time Localization
  98. GRB 240615A: Swift ToO observations
  99. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  100. GRB 240615A: Fermi GBM Final Real-time Localization

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