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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

32766 results found.

  1. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  2. GRB 240713A: Tiled Swift observations
  3. GRB 240713A: J-band upper limit from WINTER
  4. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  5. GRB 240713A: JinShan optical upper limits
  6. GRB 240713A: OHP/T120 optical upper limit
  7. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  8. GRB240713A: X-ray follow-up observation with EP-FXT
  9. GRB240713A: Optical upper limit with Kinder observations
  10. Fermi Sub-threshold Observation of GRB240713A
  11. EP240708a: GSP optical upper limit
  12. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  13. EP240708a: KAIT optical upper limit
  14. Fermi GRB 240710A: Global MASTER-Net observations report
  15. EP240708a: NOT optical observations
  16. EP240708a: SVOM/C-GFT optical upper limit
  17. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  18. EP240708a: Optical upper limits with Kinder observations
  19. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  20. EP240703b: GSP optical upper limit
  21. EP240703b: TRT optical upper limits
  22. EP240703a: TRT further optical observation
  23. EP240702a: TRT optical upper limits
  24. Konus-Wind detection of GRB 240627A
  25. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  26. EP240703a and EP240703b: Swift/XRT upper limits
  27. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  28. EP240703a: KAIT optical upper limit
  29. EP240703a: BTA observations
  30. EP240703c: Kinder optical follow-up and Swift XRT observations
  31. EP240703a: Liverpool Telescope optical follow-up observations
  32. EP240703a/GRB 240703A: TRT optical candidate likely not real
  33. EP240703a: Kinder optical follow-up observations
  34. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  35. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  36. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  37. IPN triangulation of GRB 240627A
  38. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  39. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  40. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  41. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  42. EP240702a: Swift/XRT upper limit
  43. EP240702a: GSP optical upper limit
  44. Fermi GRB 240702A: Global MASTER-Net observations report
  45. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  46. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  47. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  48. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  50. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  51. Fermi GRB 240629A: Global MASTER-Net observations report
  52. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  53. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  54. IPN triangulation of GRB 240619C
  55. GRB 240627A: NuSTAR Detection of the long GRB
  56. GRB 240615A: SAI CMO J- band observations
  57. EP240626a: Montarrenti Observatory optical upper limit
  58. LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate
  59. EP240625a: GRANDMA Optical Upper Limits
  60. EP240626a: EP-FXT detection of the X-ray emission
  61. GRB 240624A: Swift-BAT refined analysis
  62. Konus-Wind detection of GRB 240619A
  63. Fermi GRB 240625B: Global MASTER-Net observations report
  64. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  65. GRB 240625A: Fermi GBM Observation
  66. EP240625a: NOT optical counterpart candidate
  67. EP240625a: EP-FXT detection of the X-ray emission
  68. GRB 240624B: GRBAlpha detection
  69. GRB240624A: Fermi GBM Observation
  70. Swift GRB 240624A: Global MASTER-Net observations report
  71. GRB240615A: Gemini-North observations of the BAT and XRT positions
  72. Fermi GRB 240624A: Global MASTER-Net observations report
  73. GRB240615A: Gemini-North observations of the BAT and XRT positions
  74. GRB 240619A: detection of a radio counterpart with AMI-LA
  75. EP240618a: NOT further optical observations
  76. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  77. GRB 240619A: J-band detection with WINTER
  78. LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
  79. EP240618a: NOT optical counterpart candidate
  80. LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
  81. GRB 240529A: JinShan optical observations
  82. LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
  83. LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
  84. EP240618a: GSP optical upper limit
  85. LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
  86. LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
  87. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  89. IPN triangulation of GRB 240615A (short)
  90. X-ray transient EP240618a: Fermi/GBM non-detection
  91. GRB 240619A: GRBAlpha detection
  92. EP240618a: Swift/XRT upper limit
  93. EP240617a: tentative Swift/XRT detection of the afterglow
  94. GRB 240619A: Swift-XRT probable afterglow detection
  95. GRB 240619A: Swift ToO observations
  96. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  97. GRB 240619C: NuSTAR automated detection of the GRB
  98. GRB 240619A: Fermi GBM Observation
  99. Fermi GBM Sub-Threshold Detection of GRB 240619C
  100. GRB 240619A: GOTO candidate optical afterglow

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