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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"

25907 results found.

  1. GRB 241115A: Fermi GBM Observation
  2. GRB 241115A: LCOGT Optical Upper Limits
  3. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  4. Swift GRB 241115A: Global MASTER-Net observations report
  5. GRB 241115A: Swift detection of a burst
  6. EP 241113a: LBT possible optical counterpart
  7. GRB 241113B: KAIT Optical Afterglow Candidate
  8. GRB 241113A: Swift-BAT refined analysis
  9. GRB 241113A: PRIME near-infrared upper limits
  10. GRB 241113A: J-band observations with WINTER
  11. GRB 241113B: Swift-XRT observations
  12. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  13. GRB 241113A: KAIT optical observations
  14. GRB 241113A: Swift-XRT refined Analysis
  15. GRB 241113A: Swift/UVOT Detection
  16. GRB 241113A: REM detection of the optical/NIR afterglow
  17. Konus-Wind detection of GRB 241107A (short/hard)
  18. GRB 241113B: Swift ToO observations
  19. GRB 241113A: LCO optical observations
  20. GRB 241113A: Enhanced Swift-XRT position
  21. GRB241113A: LCOGT (40-cm) optical counterpart detection
  22. GRB 241113A: MASTER010615.66-224018.2 optical counterpart detection
  23. GRB 241113A: Swift detection of a burst with an optical counterpart
  24. Swift GRB241113.33: Global MASTER-Net observations report
  25. GRB 241112B: AbAO optical upper limit
  26. GRB 241107A: GROWTH-India telescope optical upper limit
  27. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  28. GRB 241112B: Swift-XRT afterglow detection
  29. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  30. GRB 241112B: SVOM/VT afterglow detection
  31. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  32. GRB 241112B: Swift ToO observations
  33. GRB 241107A: INTEGRAL IBIS localization
  34. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  35. IPN triangulation of GRB 241107A (short/hard)
  36. GRB 241025A: VZLUSAT-2 detection
  37. GRB 241030B: TESS detection of optical counterpart
  38. EP241107a: AbAO optical upper limit
  39. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  40. GRB 241108A: Swift-XRT observations
  41. EP241107A: MASTER optical observations of xray transient
  42. EP241107a: KAIT optical observations
  43. GRB 241108A: Swift ToO observations
  44. GRB 241030A: TESS observations
  45. EP241107a: Kinder optical follow-up observations
  46. EP241107a: AKO Optical Afterglow Follow-Up Observations
  47. GRB 241105A: EP-FXT follow-up observations
  48. GRB 241105A: SVOM/GRM observation
  49. GRB 241105a: PRIME near-infrared upper limits
  50. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  51. EP241107a: GIT optical observations
  52. EP241107a: AKO Optical Afterglow Detection
  53. GRB 241025A: LBT optical observations
  54. GRB241105A: Gemini-South Optical Afterglow Detection
  55. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  56. GRB 241105A: Swift/UVOT Detection
  57. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  58. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  59. GRB 241105A: BOOTES-7 optical detection
  60. GRB 241030A: Mondy optical observations
  61. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  62. GRB 241105A: SVOM/VT optical afterglow observations
  63. GRB 241105A: Swift-XRT afterglow detection
  64. GRB 241104A: Swift-XRT observations
  65. GRB 241105A: Swift ToO observations
  66. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  67. GRB 241104A: Swift ToO observations
  68. GRB 241104A: SVOM/VT optical candidate
  69. GRB 241010A: host galaxy redshift z = 0.977
  70. GRB 241030A: GRBAlpha detection
  71. EP241103a: GIT optical upper limit
  72. EP241103a: GOTO optical upper limit
  73. EP241103a: Swift XRT detection and improved X-ray position
  74. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  75. GRB 241030A: Rapid release of TESS data.
  76. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  77. Swift GRB 241101A: Global MASTER-Net observations report
  78. GRB 241101A: FRAM-ORM optical limit
  79. GRB 241101A: Swift-BAT refined analysis
  80. GRB 241030B: Swift-XRT refined Analysis
  81. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  82. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  83. GRB 241101A: Swift detection of a burst
  84. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  85. GRB 241030B: Montarrenti Observatory optical upper limit
  86. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  87. GRB 241030A: Fermi GBM Observation
  88. GRB 241030B: LCOGT Optical Upper Limits
  89. GRB 241030B: Swift-BAT refined analysis
  90. GRB 241030A: Swift-BAT refined analysis
  91. GRB 241030B: Swift/UVOT Detection
  92. GRB 241029A: LCO optical detection
  93. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  94. Swift GRB241030.77: Global MASTER-Net observations report
  95. GRB 241030B: SVOM/GRM observation
  96. GRB 241030B : MITSuME Akeno optical upper limits
  97. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  98. GRB 241030B: SVOM/VT optical afterglow observations
  99. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  100. EP241030a: EP detection of GRB 241030A X-ray Afterglow

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