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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"
  1. GRB 120402A: optical upper limit
  2. GRB 120320A: optical upper limit in Mondy observatory
  3. GRB 120320A: early optical upper limit
  4. GRB 120403A: MASTER follow up observations
  5. GRB 120402A: MASTER follow up observations
  6. GRB 120403A, Swift-BAT refined analysis
  7. GRB 120402B: Fermi GBM detection
  8. GRB 120328B: Pi of the Sky simultaneous upper limits
  9. GRB 120326A: Bassano Bresciano Observatory - correction for GCN Cir 13178
  10. GRB 120403A: Swift detection of a burst
  11. GRB 120402A: Swift detection of a possible burst or noise
  12. GRB 120326A: Cima Rest and Bassano Brescia
  13. GRB 120327A: SMARTS optical/IR afterglow observations
  14. GRB 120401A: Swift-XRT refined Analysis
  15. GRB 120401A: Swift-BAT refined analysis
  16. GRB 120326A: HCT optical observations
  17. GRB 120401A: Enhanced Swift-XRT position
  18. GRB 120401A: Prompt enhanced Swift-XRT position
  19. GRB 120401A: Swift detection of a burst
  20. GRB 120326A: EVLA Observations
  21. GRB120327A - ATCA radio afterglow detection at 34GHz
  22. GRB 120324A: CrAO optical upper limit
  23. GRB 120326A: Bassano Bresciano Observatory lightcurve analisis
  24. GRB 120326A: MITSuME Ishigakijima Optical Observation at 3 days afterthe burst
  25. GRB 120326A : Suzaku WAM observation of the prompt emission
  26. GRB 120326A: CARMA 3mm detection
  27. GRB 120324A, the review of the sky area in plate archives
  28. Swift trigger 518853 is most likely GX 301-2
  29. GRB 120326A: Bassano Bresciano Observatory optical observations
  30. GRB 120328A: MITSuME Ishigakijima Optical Upper Limits
  31. GRB 120326A: MITSuME Ishigakijima Optical Observation at 2 days afterthe burst
  32. GRB 120327A: MITSuME Ishigakijima Optical Upper Limits at 1 day afterthe burst
  33. Swift trigger 518853: MASTER-ICATE possible OT
  34. The Swift-XRT source associated with trigger 518853 is a cosmic ray
  35. Trigger 518853: Swift detection of a probable Galactic transient
  36. GRB 120328B: Fermi-LAT Observations
  37. GRB 120327A: Zadko optical observations
  38. GRB 120328B: Fermi GBM detection
  39. long/intense GRB 120328B: MASTER follow up observations
  40. GRB 120328A: Swift/UVOT Upper Limits
  41. GRB 120326A: Bassano Bresciano Observatory further optical observations
  42. GRB 120328A: Swift-XRT refined Analysis
  43. Konus-Wind observation of GRB 120328B
  44. IPN Triangulation of GRB 120328B (long/intense)
  45. GRB 120327A: MITSuME Ishigakijima Optical Observation
  46. GRB 120326A: MITSuME Ishigakijima Optical Observation
  47. GRB 120328A: Swift-BAT refined analysis
  48. GRB 120328A: Enhanced Swift-XRT position
  49. GRB 120327A: NOT optical observations
  50. GRB 120328A: TAROT La Silla observatory optical observations
  51. GRB 120326A: Xinglong TNT further optical observation��correction for GCN Cir 13149)
  52. GRB 120326A: Xinglong TNT further optical observation
  53. Skynet/PROMPT observations of GRB120328A
  54. GRB 120328A: Swift detection of a burst
  55. GRB 120327A: GTC redshift confirmation
  56. GRB 120326A: Fermi GBM Observation
  57. GRB 120327A afterglow detection
  58. GRB 120326A: PAIRITEL NIR Observations
  59. GRB 120326A: Bassano Bresciano Observatory optical observations
  60. GRB 120327A: Swift-XRT refined Analysis
  61. GRB 120327A: CQUEAN grizY Observation
  62. GRB 120326A: LOAO R-band Observations
  63. GRB 120327A: Swift/UVOT further analysis
  64. GRB 120327A: Swift-BAT refined analysis
  65. GRB 120326A : SMA submm observation
  66. GRB 120327A: Enhanced Swift-XRT position
  67. GRB 120327A: X-shooter redshift
  68. GRB 120327A: Gemini-South redshift
  69. GRB 120327A: TAROT La Silla observatory optical decay
  70. GRB120326A: TNT optical observation
  71. GRB 120327A: IAC80 I-band observations
  72. GROND observations of GRB 120327A
  73. GRB 120327A: REM NIR and optical observations
  74. Skynet/PROMPT observations of GRB120327A
  75. GRB 120326A: Maisoncelles Observatory optical observations
  76. GRB 120327A: Liverpool Telescope Observations
  77. GRB 120327A: TAROT La Silla observatory optical detection
  78. GRB 120327A: Swift detection of a burst with an optical counterpart
  79. GRB 120326A: optical observation of GMG
  80. GRB 120326A : LOT optical observation
  81. GRB 120326A: Swift-BAT refined analysis
  82. GRB 120326A: T17 optical observations
  83. GRB 120326A: GTC redshift
  84. GRB 120326A: CQUEAN grizY Observation
  85. GRB 120323A: MASTER follow up observations
  86. GRB 120326A: Swift-XRT refined Analysis
  87. GRB 120326A: Swift/UVOT Detection
  88. GRB 120326A: Optical observations at Crni Vrh
  89. GRB120326A: IAC80 observations
  90. GRB 120326A: Liverpool Telescope observations
  91. GRB 120326A: Enhanced Swift-XRT position
  92. Skynet/Dolomiti Observations of GRB120326A
  93. GRB 120326A: TAROT Calern observatory afterglow optical decay
  94. GRB 120326A: TAROT Calern observatory afterglow optical detection
  95. GRB 120326A: ROTSE-III Optical Limits
  96. GRB 120326A: Swift detection of a burst
  97. GRB 120323A: Fermi LAT observations
  98. Konus-Wind observation of GRB 120323A
  99. IPN Triangulation of GRB 120323A (short/very intense)
  100. GRB 120324A: Swift-XRT refined Analysis

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