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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"

23445 results found.

  1. GRB 120404A, Optical Observations
  2. GRB 120404A: EVLA Detection
  3. GRB 120404A: MASTER OT observations
  4. GRB120404A: GROND observations show steeply decaying afterglow
  5. GRB 120404A: Swift/UVOT Detection
  6. GRB 120404A: MITSuME Ishigakijima Optical Observation
  7. GRB 120404A: MITSuME Okayama Optical Observation
  8. GRB 120401A: GROND Detection of an optical/NIR afterglow candidate
  9. GRB 120404A: Enhanced Swift-XRT position
  10. GRB 120402B: MASTER early OT limit
  11. GRB 120403B: TAROT La Silla observatory optical observations
  12. GRB 120404A: Gemini-N Redshift
  13. GRB 120403B: AAT nIR observations
  14. GRB 120404A: Faulkes Telescope North afterglow confirmation
  15. GRB 120404A: Swift detection of a burst with an optical counterpart
  16. GRB 120403B: Swift/UVOT Upper Limits
  17. GRB 120403B: Enhanced Swift-XRT position
  18. GRB 120403B: Swift detection of a burst
  19. GRB 120402A: optical upper limit
  20. GRB 120320A: optical upper limit in Mondy observatory
  21. GRB 120320A: early optical upper limit
  22. GRB 120402B: Fermi GBM detection
  23. GRB 120328B: Pi of the Sky simultaneous upper limits
  24. GRB 120326A: Bassano Bresciano Observatory - correction for GCN Cir 13178
  25. GRB 120403A: Swift detection of a burst
  26. GRB 120402A: Swift detection of a possible burst or noise
  27. GRB 120326A: Cima Rest and Bassano Brescia
  28. GRB 120327A: SMARTS optical/IR afterglow observations
  29. GRB 120401A: Enhanced Swift-XRT position
  30. GRB 120401A: Swift detection of a burst
  31. GRB 120326A: EVLA Observations
  32. GRB 120324A: CrAO optical upper limit
  33. GRB 120326A: Bassano Bresciano Observatory lightcurve analisis
  34. GRB 120326A: MITSuME Ishigakijima Optical Observation at 3 days afterthe burst
  35. GRB 120326A : Suzaku WAM observation of the prompt emission
  36. GRB 120326A: CARMA 3mm detection
  37. GRB 120326A: Bassano Bresciano Observatory optical observations
  38. GRB 120328A: MITSuME Ishigakijima Optical Upper Limits
  39. GRB 120326A: MITSuME Ishigakijima Optical Observation at 2 days afterthe burst
  40. GRB 120327A: MITSuME Ishigakijima Optical Upper Limits at 1 day afterthe burst
  41. Swift trigger 518853: MASTER-ICATE possible OT
  42. The Swift-XRT source associated with trigger 518853 is a cosmic ray
  43. Trigger 518853: Swift detection of a probable Galactic transient
  44. GRB 120328B: Fermi-LAT Observations
  45. GRB 120327A: Zadko optical observations
  46. GRB 120328A: Swift/UVOT Upper Limits
  47. GRB 120326A: Bassano Bresciano Observatory further optical observations
  48. IPN Triangulation of GRB 120328B (long/intense)
  49. GRB 120327A: MITSuME Ishigakijima Optical Observation
  50. GRB 120326A: MITSuME Ishigakijima Optical Observation
  51. GRB 120328A: Enhanced Swift-XRT position
  52. GRB 120328A: TAROT La Silla observatory optical observations
  53. Skynet/PROMPT observations of GRB120328A
  54. GRB 120328A: Swift detection of a burst
  55. GRB 120327A afterglow detection
  56. GRB 120326A: PAIRITEL NIR Observations
  57. GRB 120326A: Bassano Bresciano Observatory optical observations
  58. GRB 120327A: Swift/UVOT further analysis
  59. GRB 120327A: Swift-BAT refined analysis
  60. GRB 120326A : SMA submm observation
  61. GRB 120327A: Enhanced Swift-XRT position
  62. GROND observations of GRB 120327A
  63. GRB 120327A: REM NIR and optical observations
  64. Skynet/PROMPT observations of GRB120327A
  65. GRB 120327A: TAROT La Silla observatory optical detection
  66. GRB 120327A: Swift detection of a burst with an optical counterpart
  67. GRB 120326A: optical observation of GMG
  68. GRB 120326A : LOT optical observation
  69. GRB 120326A: Swift/UVOT Detection
  70. GRB 120326A: Optical observations at Crni Vrh
  71. GRB 120326A: Enhanced Swift-XRT position
  72. Skynet/Dolomiti Observations of GRB120326A
  73. GRB 120326A: TAROT Calern observatory afterglow optical detection
  74. GRB 120326A: ROTSE-III Optical Limits
  75. GRB 120326A: Swift detection of a burst
  76. GRB 120323A: Fermi LAT observations
  77. IPN Triangulation of GRB 120323A (short/very intense)
  78. GRB 120323A: Fermi GBM detection
  79. GRB 120324A: GROND observations
  80. GRB 120324A: CQUEAN rizY Observation
  81. GRB 120324A: Swift/UVOT Upper Limits
  82. GRB 120324A: TAROT La Silla observatory optical observations
  83. GRB 120324A: Enhanced Swift-XRT position
  84. GRB 120324A: Swift detection of a burst
  85. GRB 120316A : Suzaku WAM observation of the prompt emission
  86. GRB 120320A: Zadko optical observations
  87. GRB 120316A: Fermi-GBM and Fermi-LAT Observations
  88. GRB 120229A: Magellan observations and limit on an optical afterglow
  89. GRB 120320A: Swift/UVOT Upper Limits
  90. GRB 120320A: MITSuME Okayama Optical upper limits
  91. GRB 120320A , optical observations
  92. GRB 120320A: BOOTES-4 optical upper limit
  93. GRB 120320A: Gemini-N and UKIRT observations
  94. GRB 120320A: Enhanced Swift-XRT position
  95. IPN Triangulation of GRB 120316A
  96. GRB 120320A: Swift detection of a burst
  97. Trigger 517876 is a Swift detection of GX 5-1
  98. GRB 120302A: Swift XRT refined analysis
  99. GRB 120312A: CrAO optical upper limit
  100. GRB 120312A: Gemini and UKIRT imaging

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