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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"

28199 results found.

  1. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  2. GRB 241025B: Fermi GBM Final Localization
  3. EP 241021a: Swift-XRT observations
  4. EP241025a (GRB 241025A): EP observations update
  5. GRB 241025A : SVOM/VT optical afterglow observations
  6. EP 241021A: Swift ToO observations
  7. EP241021a: Liverpool Telescope optical follow-up observations
  8. GRB 241025A: Enhanced Swift-XRT position
  9. GRB 241025A: DDOTI Afterglow detection
  10. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  11. GRB 241025A: TRT optical afterglow observation
  12. GRB 241025A: Fermi GBM Final Real-time Localization
  13. GRB 241025A: Swift detection of a burst with an optical counterpart
  14. GRB 241001A: ATCA radio observations
  15. GRB 241024B: Fermi GBM Final Localization
  16. EP241021a: No Detection in Fermi-GBM Observation
  17. GRB 241010A: VIRT Optical Upper Limit
  18. GRB 241024A: Fermi GBM Final Localisation
  19. EP241021a: VLT/FORS2 redshift z = 0.75
  20. EP241021a: KAIT optical observations
  21. EP241021a: EP-FXT follow-up observation update
  22. EP241021a: Optical counterpart observations with the Liverpool Telescope
  23. EP241021a: 1.3m DFOT Optical observations
  24. EP241021a: NOT likely optical counterpart
  25. GRB241017A: 1.3m DFOT optical upper limit
  26. GRB 241018A: 1.3m DFOT Optical upper limit
  27. GRB 241018A: EP-FXT afterglow detection
  28. EP241021a: EP detection of a fast X-ray transient
  29. Konus-Wind detection of GRB 241018A
  30. GRB 241018A: BOOTES-4/MET optical upper limit
  31. GRB 241018A: Mondy optical upper limit
  32. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  33. GRB 241018A: GROWTH-India telescope optical upper limit
  34. GRB 241018A: Swift-XRT observations
  35. GRB 241018A: REM optical/NIR upper limits
  36. GRB 241018A: NOT optical observations
  37. GRB 241018A: LCO/0.4m optical upper limits
  38. GRB 241018A: Swift ToO observations
  39. GRB 241006A: VIRT Optical Upper Limit
  40. GRB 240727A: VIRT Optical Upper Limit
  41. GRB 241018A: X-ray afterglow candidate observed by MXT
  42. GRB 241018A: Detection of a bright long GRB by SVOM
  43. GRB 241017A: Swift-XRT observations
  44. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  45. GRB 241001A: EP-FXT afterglow detection
  46. GRB241016C: Fermi GBM Final Localization
  47. GRB 241017A: Swift ToO observations
  48. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  49. GRB 241016B: Fermi GBM Final Localization
  50. GRB 241016A: Fermi GBM Final Real-time Localization
  51. IceCube alert 139977_2910365 retraction
  52. GRB 240916A: radio detection with the VLA
  53. GRB 241009A: LCO optical upper limits
  54. GRB 241013B: Fermi GBM Final Real-time Localization
  55. GRB 241013A: Fermi GBM Final Real-time Localization
  56. GRB 241011A: Fermi GBM Final Real-time Localization
  57. GRB 241009A: GRANDMA optical upper limits
  58. GRB 241009A: Swift-XRT afterglow detection
  59. GRB 241010A: JinShan optical observations and potential host galaxy
  60. GRB 241006A: ATCA Radio Upper Limits
  61. GRB 241010A: Swift-XRT refined Analysis
  62. GRB 241010A: J-band observations with WINTER
  63. GRB 241010B: Fermi GBM Final Real-time Localization
  64. GRB 241010A: Enhanced Swift-XRT position
  65. GRB 241010A: LCO optical observations
  66. GRB 241010A: Swift detection of a burst with an optical counterpart
  67. GRB 241009A: Swift ToO observations
  68. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  69. GRB 241008A: Fermi-LAT detection
  70. GRB 241002B: Swift-XRT afterglow detection
  71. GRB 241002A: NOT optical upper limits
  72. GRB 241008A: Fermi GBM Final Real-time Localization
  73. IceCube-241006A: No candidates from the Zwicky Transient Facility
  74. GRB 241006A: GRANDMA optical upper limits
  75. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  76. GRB 240910A: LBT optical observations
  77. GRB 241006A: Swift-XRT refined Analysis
  78. GRB 241006A: PRIME near-infrared upper limits
  79. GRB 241006A: Swift/UVOT Upper Limits
  80. GRB 241006A: SVOM/VT follow-up and optical upper limit
  81. GRB 241001A: Swift-XRT afterglow detection
  82. GRB 241006A: Enhanced Swift-XRT position
  83. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  84. GRB 241006A: Swift detection of a burst
  85. LIGO/Virgo/KAGRA S241005bo: Retraction of GW compact binary merger candidate
  86. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  87. GRB 241002B: Fermi GBM Observation
  88. GRB 241002B: Swift-XRT observations
  89. GRB 241002B: Swift ToO observations
  90. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  91. Konus-Wind detection of GRB 240926A
  92. GRB 241002B: PRIME near-infrared detection
  93. GRB 241002C: Swift ToO observations
  94. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  95. IPN triangulation of GRB 240930B / EP 240930a
  96. GRB 241001A : SVOM/VT optical detection
  97. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  98. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  99. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  100. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT

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