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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"

37549 results found.

  1. GRB 241002B: GOTO optical counterpart candidate
  2. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  3. GRB 241001A: correction to GCN 37667
  4. GRB 240929A: Liverpool Telescope prompt followup observations
  5. Fermi GRB 241002B: Global MASTER-Net observations report
  6. GRB 241001A: Swift-XRT observations
  7. GRB 241002B: Fermi GBM Final Real-time Localization
  8. GRB241001A: optical afterglow candidate
  9. GRB 241002A: 1.5m OSN optical upper limit
  10. GRB 241002A: Enhanced Swift-XRT position
  11. GRB 241001A: BOOTES-6/DPRT optical upper limit
  12. GRB 241002A: Swift detection of a burst
  13. GRB 240930B: Fermi GBM Observation
  14. GRB 241001A: Swift ToO observations
  15. GRB 240930B: GRBAlpha detection
  16. GRB 240929A: GRBAlpha detection
  17. EP240930a : KAIT optical upper limit
  18. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  19. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  20. EP240930a: EP-FXT follow-up observation update
  21. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  22. EP240930a: GOTO optical upper limits
  23. GRB 240929A: SVOM/GRM observation
  24. EP240930a: EP-WXT detection of a fast X-ray transient
  25. GRB 240929A : Leavitt Observatory optical upper limit
  26. Fermi GRB 240930B: Global MASTER-Net observations report
  27. GRB 240930B: Fermi GBM Final Real-time Localization
  28. IPN triangulation of GRB 240926A
  29. GRB 240825A: LBT optical observations
  30. GRB 240928A: SVOM/GRM observation
  31. Fermi GRB 240930A: Global MASTER-Net observations report
  32. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  33. GRB 240930A: Fermi GBM Final Real-time Localization
  34. Fermi trigger No 749339671: Global MASTER-Net observations report
  35. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  36. GRB 240929A long GRB detected by INTEGRAL
  37. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  38. Fermi GRB 240929A: Global MASTER-Net observations report
  39. GRB 240929A: Fermi GBM Final Real-time Localization
  40. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  41. Konus-Wind detection of GRB 240912A
  42. Swift Trigger 1256950 is probably not a GRB
  43. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  44. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  45. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  46. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  47. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  48. GRB 240926A: SVOM/GRM observation
  49. Konus-Wind detection of GRB 240905B
  50. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  51. EP240919a / GRB 240919A: SVOM/VT upper limit
  52. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  53. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  54. Konus-Wind detection of GRB 240918B
  55. IPN triangulation of GRB 240918B
  56. GRB 240905B: VZLUSAT-2 detection
  57. GRB 240918B: AstroSat CZTI detection
  58. EP240913A/GRB 240913C: AbAO optical upper limit
  59. EP240919a / GRB 240919A: Mondy optical upper limit
  60. EP240913a/GRB 240913C: 1.6m Mephisto observations
  61. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  62. EP240919a / GRB 240919A: REM optical and NIR upper limits
  63. EP240919a / GRB 240919A: KAIT optical upper limit
  64. GRB 240414A: further radio observations with the VLA
  65. GRB 240919A / EP240919a: SVOM/GRM observation
  66. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  67. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  68. GRB 240910A: radio detection with the VLA
  69. EP240919a: JinShan optical upper limits
  70. EP240919a is likely a GRB event (duplicate submission of 37563)
  71. EP240919a is likely a GRB event
  72. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  73. GRB 240918B: Fermi GBM Detection
  74. GRB 240910A: further Swift observations and confirmation of afterglow
  75. Fermi GRB 240918A: Global MASTER-Net observations report
  76. GRB 240918A: Fermi GBM Final Real-time Localization
  77. GRB 240916A: GRBAlpha detection
  78. GRB 240914B: GRBAlpha detection
  79. GRB 240916A: NOT optical observation
  80. GRB 240912A: Swift-BAT refined analysis
  81. IPN triangulation of GRB 240913C / EP 240913a
  82. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  83. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  84. GRB 240916A: Fermi GBM Observation
  85. GRB 240821A: radio observation with the VLA
  86. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  87. GRB 240916A: Swift-XRT afterglow detection
  88. GRB 240916A: Swift ToO observations
  89. GRB 240916A: JinShan optical decay in one of the two GOTO candidates
  90. GRB 240916B: Fermi GBM Final Real-time Localization
  91. GRB 240914B: Fermi GBM Final Localization
  92. GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
  93. GRB 240916A INTEGRAL SPI ACS LIGHT CURVE
  94. GRB 240916A: Fermi GBM Final Real-time Localization
  95. Fermi Gamma-ray Burst Monitor trigger 748124309/240915846 is not a GRB
  96. EP240913a/GRB 240913C: KAIT optical upper limit
  97. EP240913a / GRB 240913C INTEGRAL SPI ACS LIGHT CURVE
  98. GRB 240913C: Fermi GBM detection
  99. GRB 240914A: Swift-XRT observations
  100. GRB 240913C: Joint location by ETJASMIN

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