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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"

31727 results found.

  1. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  2. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  3. EP240702a: Swift/XRT upper limit
  4. EP240702a: GSP optical upper limit
  5. Fermi GRB 240702A: Global MASTER-Net observations report
  6. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  7. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  8. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  9. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  11. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  12. Fermi GRB 240629A: Global MASTER-Net observations report
  13. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  14. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  15. IPN triangulation of GRB 240619C
  16. GRB 240627A: NuSTAR Detection of the long GRB
  17. GRB 240615A: SAI CMO J- band observations
  18. EP240626a: Montarrenti Observatory optical upper limit
  19. LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate
  20. EP240625a: GRANDMA Optical Upper Limits
  21. EP240626a: EP-FXT detection of the X-ray emission
  22. GRB 240624A: Swift-BAT refined analysis
  23. Konus-Wind detection of GRB 240619A
  24. Fermi GRB 240625B: Global MASTER-Net observations report
  25. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  26. GRB 240625A: Fermi GBM Observation
  27. EP240625a: NOT optical counterpart candidate
  28. EP240625a: EP-FXT detection of the X-ray emission
  29. GRB 240624B: GRBAlpha detection
  30. GRB240624A: Fermi GBM Observation
  31. Swift GRB 240624A: Global MASTER-Net observations report
  32. GRB240615A: Gemini-North observations of the BAT and XRT positions
  33. Fermi GRB 240624A: Global MASTER-Net observations report
  34. GRB240615A: Gemini-North observations of the BAT and XRT positions
  35. GRB 240619A: detection of a radio counterpart with AMI-LA
  36. EP240618a: NOT further optical observations
  37. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  38. GRB 240619A: J-band detection with WINTER
  39. LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
  40. EP240618a: NOT optical counterpart candidate
  41. LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
  42. GRB 240529A: JinShan optical observations
  43. LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
  44. LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
  45. EP240618a: GSP optical upper limit
  46. LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  49. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  50. IPN triangulation of GRB 240615A (short)
  51. X-ray transient EP240618a: Fermi/GBM non-detection
  52. GRB 240619A: GRBAlpha detection
  53. EP240618a: Swift/XRT upper limit
  54. EP240617a: tentative Swift/XRT detection of the afterglow
  55. GRB 240619A: Swift-XRT probable afterglow detection
  56. GRB 240619A: Swift ToO observations
  57. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  58. GRB 240619C: NuSTAR automated detection of the GRB
  59. GRB 240619A: Fermi GBM Observation
  60. Fermi GBM Sub-Threshold Detection of GRB 240619C
  61. GRB 240619A: GOTO candidate optical afterglow
  62. EP240618a: Abastumani optical observationsEP240618a
  63. GRB 240615A: NOT optical observations
  64. EP240618a: GRANDMA Optical Upper Limits
  65. EP240618a: TRT optical upper limit
  66. Fermi GRB 240619A: Global MASTER-Net observations report
  67. EP240617a: STEP/T80S optical limits
  68. GRB 240615A: possible transient detection from Wendelstein observations
  69. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  70. LIGO/Virgo/KAGRA S240615dg: Updated Sky localization
  71. LIGO/Virgo/KAGRA S240618ah: Updated Sky localization
  72. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  73. GRB240615A: 1.3m DFOT optical upper limit
  74. EP240617a is likely a GRB event
  75. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  76. GRB 240615A: J-band upper limits from WINTER
  77. GRB 240615A: Fermi GBM Observation
  78. LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
  79. GRB 240615A: GECAM detection
  80. X-ray transient EP240414a: Chandra late time observation
  81. GRB 240615A: FLWO-1.2m optical upper limits
  82. Fermi GRB 240616A: Global MASTER-Net observations report
  83. Konus-Wind detection of GRB 240615A (short/hard)
  84. GRB 240615A: GOTO optical upper limits
  85. GRB 240615A: Swift ToO observations
  86. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  87. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  89. GRB 240603A: VZLUSAT-2 detection
  90. GRB 240612A: GRBAlpha detection
  91. Fermi GRB 240612B: Global MASTER-Net observations report
  92. Fermi GRB 240612A: Global MASTER-Net observations report
  93. GRB 240607A: GECAM detection of a bright long burst
  94. Fermi GRB 240611A: Global MASTER-Net observations report
  95. Konus-Wind detection of GRB 240607A
  96. EXO 0748-676: Swift-BAT refined analysis
  97. GRB 240529A: LBT optical detection and late temporal decay
  98. GRB 240529A : MITSuME Akeno optical afterglow detection
  99. Fermi GRB 240610A: Global MASTER-Net observations report
  100. IPN triangulation of GRB 240607A

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