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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"

14327 results found.

  1. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  2. GRB 241016B: Fermi GBM Final Localization
  3. GRB 241016A: Fermi GBM Final Real-time Localization
  4. IceCube alert 139977_2910365 retraction
  5. GRB 240916A: radio detection with the VLA
  6. GRB 241013B: SVOM/GRM observation
  7. GRB 241013B: Fermi GBM Final Real-time Localization
  8. GRB 241013A: Fermi GBM Final Real-time Localization
  9. GRB 241011A: Fermi GBM Final Real-time Localization
  10. GRB 241009A: Swift-XRT afterglow detection
  11. GRB 241010B: Fermi GBM Final Real-time Localization
  12. GRB 241010A: Swift detection of a burst with an optical counterpart
  13. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  14. GRB 241008A: Fermi-LAT detection
  15. GRB 241002B: Swift-XRT afterglow detection
  16. GRB 241008A: Fermi GBM Final Real-time Localization
  17. IceCube-241006A: No candidates from the Zwicky Transient Facility
  18. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  19. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  20. GRB 241006A: PRIME near-infrared upper limits
  21. GRB 241001A: Swift-XRT afterglow detection
  22. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 241006A: Swift detection of a burst
  24. LIGO/Virgo/KAGRA S241005bo: Retraction of GW compact binary merger candidate
  25. GRB 241004A: SVOM/GRM observation
  26. GRB 240930B / EP 240930a: SVOM/GRM observation
  27. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  28. Konus-Wind detection of GRB 240926A
  29. GRB 241002B: PRIME near-infrared detection
  30. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  31. IPN triangulation of GRB 240930B / EP 240930a
  32. GRB 241001A : SVOM/VT optical detection
  33. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  34. GRB 241002D: SVOM/GRM observation
  35. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  36. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  37. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  38. GRB 241001A: Swift/UVOT Detection
  39. GRB 241001A: VLT/X-shooter redshift
  40. EP trigger ID 01709064214: GOTO confirms detection as a flare star
  41. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  42. EP trigger ID 01709064214: the X-ray transient is most likely a stellar flare event
  43. GRB 241002B: Fermi GBM Final Real-time Localization
  44. GRB241001A: optical afterglow candidate
  45. GRB 241002A: 1.5m OSN optical upper limit
  46. GRB 241001A: BOOTES-6/DPRT optical upper limit
  47. GRB 241002A: Swift detection of a burst
  48. GRB 240930B: GRBAlpha detection
  49. GRB 240929A: GRBAlpha detection
  50. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  51. EP240930a: EP-FXT follow-up observation update
  52. GRB 240929A: SVOM/GRM observation
  53. EP240930a: EP-WXT detection of a fast X-ray transient
  54. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  55. AMON NuEM 240926A: Swift XRT Follow-up
  56. GRB 240930B: Fermi GBM Final Real-time Localization
  57. IPN triangulation of GRB 240926A
  58. GRB 240928A: SVOM/GRM observation
  59. GRB 240930A: Fermi GBM Final Real-time Localization
  60. GRB 240929A: Fermi GBM Final Real-time Localization
  61. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  62. Konus-Wind detection of GRB 240912A
  63. NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
  64. GRB 240926A: SVOM/GRM observation
  65. Konus-Wind detection of GRB 240905B
  66. EP240918b and EP240918c: EP-FXT follow-up observations
  67. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  68. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  69. Konus-Wind detection of GRB 240918B
  70. IPN triangulation of GRB 240918B
  71. GRB 240905B: VZLUSAT-2 detection
  72. GRB 240918B: AstroSat CZTI detection
  73. EP240919a: EP-FXT follow-up observation update
  74. EP240913a/GRB 240913C: 1.6m Mephisto observations
  75. EP240918a: SVOM/VT upper limit
  76. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  77. EP240918b and EP240918c: Optical upper limits with Kinder observations
  78. EP240919a: Optical upper limit with Kinder observations
  79. GRB 240919A / EP240919a: SVOM/GRM observation
  80. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  81. EP240919a: INTEGRAL SPI-ACS confirmation of reported high-energy counterpart
  82. GRB 240910A: radio detection with the VLA
  83. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  84. EP240919a: GOTO optical upper limits
  85. EP240919a: EP-WXT detection of a fast X-ray transient
  86. GRB 240918B: Fermi GBM Detection
  87. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  88. EP240918a: EP observation update
  89. GRB 240918A: Fermi GBM Final Real-time Localization
  90. EP240918a: YAHPT Optical Upper Limit
  91. GRB 240916A: GRBAlpha detection
  92. GRB 240914B: GRBAlpha detection
  93. EP240918a: an X-ray transient detected by Einstein Probe
  94. IPN triangulation of GRB 240913C / EP 240913a
  95. GRB 240825A: INTEGRAL SPI ACS LIGHT CURVE
  96. GRB 240825A: The nature of the afterglow motivates the search of the associated supernova
  97. GRB 240916A (AT 2024vlp / GOTO24fzn): VLT/X-shooter redshift
  98. GRB 240916A: Swift-XRT afterglow detection
  99. GRB 240916B: Fermi GBM Final Real-time Localization
  100. GRB 240914B: Fermi GBM Final Localization

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