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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"

31730 results found.

  1. IPN triangulation of GRB 240627A
  2. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  3. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  4. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  5. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  6. EP240702a: Swift/XRT upper limit
  7. EP240702a: GSP optical upper limit
  8. Fermi GRB 240702A: Global MASTER-Net observations report
  9. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  10. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  11. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  12. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  13. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  14. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  15. Fermi GRB 240629A: Global MASTER-Net observations report
  16. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  17. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  18. IPN triangulation of GRB 240619C
  19. GRB 240627A: NuSTAR Detection of the long GRB
  20. GRB 240615A: SAI CMO J- band observations
  21. EP240626a: Montarrenti Observatory optical upper limit
  22. LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate
  23. EP240625a: GRANDMA Optical Upper Limits
  24. EP240626a: EP-FXT detection of the X-ray emission
  25. GRB 240624A: Swift-BAT refined analysis
  26. Konus-Wind detection of GRB 240619A
  27. Fermi GRB 240625B: Global MASTER-Net observations report
  28. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  29. GRB 240625A: Fermi GBM Observation
  30. EP240625a: NOT optical counterpart candidate
  31. EP240625a: EP-FXT detection of the X-ray emission
  32. GRB 240624B: GRBAlpha detection
  33. GRB240624A: Fermi GBM Observation
  34. Swift GRB 240624A: Global MASTER-Net observations report
  35. GRB240615A: Gemini-North observations of the BAT and XRT positions
  36. Fermi GRB 240624A: Global MASTER-Net observations report
  37. GRB240615A: Gemini-North observations of the BAT and XRT positions
  38. GRB 240619A: detection of a radio counterpart with AMI-LA
  39. EP240618a: NOT further optical observations
  40. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  41. GRB 240619A: J-band detection with WINTER
  42. LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
  43. EP240618a: NOT optical counterpart candidate
  44. LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
  45. GRB 240529A: JinShan optical observations
  46. LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
  47. LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
  48. EP240618a: GSP optical upper limit
  49. LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
  51. LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
  52. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  53. IPN triangulation of GRB 240615A (short)
  54. X-ray transient EP240618a: Fermi/GBM non-detection
  55. GRB 240619A: GRBAlpha detection
  56. EP240618a: Swift/XRT upper limit
  57. EP240617a: tentative Swift/XRT detection of the afterglow
  58. GRB 240619A: Swift-XRT probable afterglow detection
  59. GRB 240619A: Swift ToO observations
  60. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  61. GRB 240619C: NuSTAR automated detection of the GRB
  62. GRB 240619A: Fermi GBM Observation
  63. Fermi GBM Sub-Threshold Detection of GRB 240619C
  64. GRB 240619A: GOTO candidate optical afterglow
  65. EP240618a: Abastumani optical observationsEP240618a
  66. GRB 240615A: NOT optical observations
  67. EP240618a: GRANDMA Optical Upper Limits
  68. EP240618a: TRT optical upper limit
  69. Fermi GRB 240619A: Global MASTER-Net observations report
  70. EP240617a: STEP/T80S optical limits
  71. GRB 240615A: possible transient detection from Wendelstein observations
  72. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  73. LIGO/Virgo/KAGRA S240615dg: Updated Sky localization
  74. LIGO/Virgo/KAGRA S240618ah: Updated Sky localization
  75. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  76. GRB240615A: 1.3m DFOT optical upper limit
  77. EP240617a is likely a GRB event
  78. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  79. GRB 240615A: J-band upper limits from WINTER
  80. GRB 240615A: Fermi GBM Observation
  81. LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
  82. GRB 240615A: GECAM detection
  83. X-ray transient EP240414a: Chandra late time observation
  84. GRB 240615A: FLWO-1.2m optical upper limits
  85. Fermi GRB 240616A: Global MASTER-Net observations report
  86. Konus-Wind detection of GRB 240615A (short/hard)
  87. GRB 240615A: GOTO optical upper limits
  88. GRB 240615A: Swift ToO observations
  89. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  90. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  91. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  92. GRB 240603A: VZLUSAT-2 detection
  93. GRB 240612A: GRBAlpha detection
  94. Fermi GRB 240612B: Global MASTER-Net observations report
  95. Fermi GRB 240612A: Global MASTER-Net observations report
  96. GRB 240607A: GECAM detection of a bright long burst
  97. Fermi GRB 240611A: Global MASTER-Net observations report
  98. Konus-Wind detection of GRB 240607A
  99. EXO 0748-676: Swift-BAT refined analysis
  100. GRB 240529A: LBT optical detection and late temporal decay

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