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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"

39182 results found.

  1. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  2. GRB 241002B: Swift ToO observations
  3. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  4. Konus-Wind detection of GRB 240926A
  5. GRB 241002B: PRIME near-infrared detection
  6. GRB 241002C: Swift ToO observations
  7. Fermi-GBM Sub-Threshold Detection of GRB 241002D
  8. IPN triangulation of GRB 240930B / EP 240930a
  9. GRB 241001A : SVOM/VT optical detection
  10. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update
  11. GRB 241002D: SVOM/GRM observation
  12. GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
  13. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  14. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
  15. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  16. GRB 241002C : MITSuME Akeno optical upper limits
  17. GRB241001A: REM optical/NIR upper limits
  18. GRB 241002A: Swift/UVOT Upper Limits
  19. GRB 241002A: Swift-XRT refined Analysis
  20. GRB 241002A: LCOGT Optical Upper Limits
  21. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  22. GRB 241001A: Swift/UVOT Detection
  23. GRB 241001A: VLT/X-shooter redshift
  24. GRB 241002B: GOTO optical counterpart candidate
  25. GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
  26. GRB 241001A: correction to GCN 37667
  27. GRB 240929A: Liverpool Telescope prompt followup observations
  28. Fermi GRB 241002B: Global MASTER-Net observations report
  29. GRB 241001A: Swift-XRT observations
  30. EP trigger ID 01709064214: the X-ray transient is most likely a stellar flare event
  31. GRB 241002B: Fermi GBM Final Real-time Localization
  32. GRB241001A: optical afterglow candidate
  33. GRB 241002A: 1.5m OSN optical upper limit
  34. GRB 241002A: Enhanced Swift-XRT position
  35. GRB 241001A: BOOTES-6/DPRT optical upper limit
  36. GRB 241002A: Swift detection of a burst
  37. GRB 240930B: Fermi GBM Observation
  38. GRB 241001A: Swift ToO observations
  39. GRB 240930B: GRBAlpha detection
  40. GRB 240929A: GRBAlpha detection
  41. EP240930a : KAIT optical upper limit
  42. GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
  43. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  44. EP240930a: EP-FXT follow-up observation update
  45. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  46. EP240930a: GOTO optical upper limits
  47. GRB 240929A: SVOM/GRM observation
  48. EP EP240930a: Global MASTER-Net observations report
  49. EP240930a: EP-WXT detection of a fast X-ray transient
  50. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  51. AMON NuEM 240926A: Swift XRT Follow-up
  52. GRB 240929A : Leavitt Observatory optical upper limit
  53. Fermi GRB 240930B: Global MASTER-Net observations report
  54. GRB 240930B: Fermi GBM Final Real-time Localization
  55. IPN triangulation of GRB 240926A
  56. GRB 240825A: LBT optical observations
  57. GRB 240928A: SVOM/GRM observation
  58. Fermi GRB 240930A: Global MASTER-Net observations report
  59. Fermi Gamma-ray Burst Monitor trigger 749362078/240930172 (GRB 240930A) is not a GRB
  60. GRB 240930A: Fermi GBM Final Real-time Localization
  61. Fermi trigger No 749339671: Global MASTER-Net observations report
  62. Fermi Gamma-ray Burst Monitor trigger 749339671/240929913 is not a GRB
  63. GRB 240929A long GRB detected by INTEGRAL
  64. GRB 240929A: BALROG localization (Fermi Trigger 749332209 / GRB 240929826)
  65. Fermi GRB 240929A: Global MASTER-Net observations report
  66. GRB 240929A: Fermi GBM Final Real-time Localization
  67. Integral GRB240929.83: Global MASTER-Net observations report
  68. Konus-Wind detection of GRB 240912A
  69. Swift Trigger 1256950 is probably not a GRB
  70. Fermi Gamma-ray Burst Monitor trigger 749191601/240928199 is not a GRB
  71. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  72. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  73. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  74. EP trigger ID 01709059262: Lick/Kast spectroscopy with 3 m Shane telescope
  75. GRB 240926A: SVOM/GRM observation
  76. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  77. Konus-Wind detection of GRB 240905B
  78. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  79. EP240919a / GRB 240919A: SVOM/VT upper limit
  80. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  81. Konus-Wind detection of GRB 240918B
  82. IPN triangulation of GRB 240918B
  83. GRB 240905B: VZLUSAT-2 detection
  84. GRB 240918B: AstroSat CZTI detection
  85. EP240913A/GRB 240913C: AbAO optical upper limit
  86. EP240919a / GRB 240919A: Mondy optical upper limit
  87. EP240913a/GRB 240913C: 1.6m Mephisto observations
  88. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  89. EP240919a / GRB 240919A: REM optical and NIR upper limits
  90. EP240919a / GRB 240919A: KAIT optical upper limit
  91. GRB 240414A: further radio observations with the VLA
  92. GRB 240919A / EP240919a: SVOM/GRM observation
  93. EP EP240919a: Global MASTER-Net observations report
  94. GRB 240910A: radio detection with the VLA
  95. EP240919a: NOT and Gemini optical observations
  96. EP240919a: JinShan optical upper limits
  97. EP240919a is likely a GRB event (duplicate submission of 37563)
  98. EP240919a is likely a GRB event
  99. GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE
  100. GRB 240918B: Fermi GBM Detection

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