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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"

38302 results found.

  1. GRB 241006A: SVOM/VT follow-up and optical upper limit
  2. IceCube Alert 241006.94: Global MASTER-Net observations report
  3. GRB 241001A: Swift-XRT afterglow detection
  4. GRB 241006A: Enhanced Swift-XRT position
  5. GRB 241006A: Swift detection of a burst
  6. Swift GRB241006.91: Global MASTER-Net observations report
  7. GRB 240930B: SVOM/C-GFT optical upper limit
  8. Fermi trigger No 749721670: Global MASTER-Net observations report
  9. GRB 241004A: SVOM/GRM observation
  10. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  11. GRB 240930B / EP 240930a: SVOM/GRM observation
  12. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  13. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  14. GRB 241002B: Fermi GBM Observation
  15. Fermi trigger No 749735279: Global MASTER-Net observations report
  16. Fermi trigger No 749630753: Global MASTER-Net observations report
  17. Fermi trigger No 749693019: Global MASTER-Net observations report
  18. GRB 241002B: Swift-XRT observations
  19. GRB 241002C: SVOM/C-GFT optical upper limit
  20. GRB 241002A: Swift-BAT refined analysis
  21. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  22. GRB 241002B: Swift ToO observations
  23. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  24. Konus-Wind detection of GRB 240926A
  25. GRB 241002B: PRIME near-infrared detection
  26. GRB 241002C: Swift ToO observations
  27. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  28. IPN triangulation of GRB 240930B / EP 240930a
  29. GRB 241001A : SVOM/VT optical detection
  30. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  31. GRB 241002D: SVOM/GRM observation
  32. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  33. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  34. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  35. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  36. GRB 241002C : MITSuME Akeno optical upper limits
  37. GRB241001A: REM optical/NIR upper limits
  38. GRB 241002A: Swift/UVOT Upper Limits
  39. GRB 241002A: Swift-XRT refined Analysis
  40. GRB 241002A: LCOGT Optical Upper Limits
  41. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  42. GRB 241001A: Swift/UVOT Detection
  43. GRB 241001A: VLT/X-shooter redshift
  44. GRB 241002B: GOTO optical counterpart candidate
  45. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  46. GRB 241001A: correction to GCN 37667
  47. GRB 240929A: Liverpool Telescope prompt followup observations
  48. Fermi GRB 241002B: Global MASTER-Net observations report
  49. GRB 241001A: Swift-XRT observations
  50. EP trigger ID 01709064214: the X-ray transient is most likely a stellar flare event
  51. GRB 241002B: Fermi GBM Final Real-time Localization
  52. GRB241001A: optical afterglow candidate
  53. GRB 241002A: 1.5m OSN optical upper limit
  54. GRB 241002A: Enhanced Swift-XRT position
  55. GRB 241001A: BOOTES-6/DPRT optical upper limit
  56. GRB 241002A: Swift detection of a burst
  57. GRB 240930B: Fermi GBM Observation
  58. GRB 241001A: Swift ToO observations
  59. GRB 240930B: GRBAlpha detection
  60. GRB 240929A: GRBAlpha detection
  61. EP240930a : KAIT optical upper limit
  62. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  63. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  64. EP240930a: EP-FXT follow-up observation update
  65. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  66. EP240930a: GOTO optical upper limits
  67. GRB 240929A: SVOM/GRM observation
  68. EP EP240930a: Global MASTER-Net observations report
  69. EP240930a: EP-WXT detection of a fast X-ray transient
  70. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  71. AMON NuEM 240926A: Swift XRT Follow-up
  72. GRB 240929A : Leavitt Observatory optical upper limit
  73. Fermi GRB 240930B: Global MASTER-Net observations report
  74. GRB 240930B: Fermi GBM Final Real-time Localization
  75. IPN triangulation of GRB 240926A
  76. GRB 240825A: LBT optical observations
  77. GRB 240928A: SVOM/GRM observation
  78. Fermi GRB 240930A: Global MASTER-Net observations report
  79. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  80. GRB 240930A: Fermi GBM Final Real-time Localization
  81. Fermi trigger No 749339671: Global MASTER-Net observations report
  82. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  83. GRB 240929A long GRB detected by INTEGRAL
  84. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  85. Fermi GRB 240929A: Global MASTER-Net observations report
  86. GRB 240929A: Fermi GBM Final Real-time Localization
  87. Integral GRB240929.83: Global MASTER-Net observations report
  88. Konus-Wind detection of GRB 240912A
  89. Swift Trigger 1256950 is probably not a GRB
  90. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  91. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  92. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  93. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  94. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  95. GRB 240926A: SVOM/GRM observation
  96. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  97. Konus-Wind detection of GRB 240905B
  98. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  99. EP240919a / GRB 240919A: SVOM/VT upper limit
  100. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst

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