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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 090728: Swift/UVOT Upper Limits
  2. GRB 090728: Enhanced Swift-XRT position
  3. GRB 090727: I-band observations from 1.23m CAHA
  4. GRB 090728, RIMOTS optical upper limits
  5. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  6. GRB 090728: Swift detection of a burst
  7. GRB 090727: Swift-BAT refined analysis
  8. GRB 090727: Swift-XRT refined analysis
  9. GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare
  10. GRB 090727: Enhanced Swift-XRT position
  11. GRB 090715B: Late-time Lick 3m observations
  12. GRB 090727: Liverpool Telescope possible OT candidate
  13. GRB 090727: Swift detection of a burst
  14. GRB090726: Swift/UVOT observations
  15. GRB 090726, Swift-BAT refined analysis
  16. GRB 090726: Afterglow candidate photometryfrom Crni Vrh
  17. GRB 090726: D50 optical observations
  18. GRB 090711: Fermi GBM detection
  19. GRB090726: 6-meter telescope redshift
  20. GRB 090726: Swift-XRT Team refined analysis
  21. GRB 090726: Enhanced Swift-XRT position
  22. GRB 090726: optical transient candidate
  23. GRB 090726: Swift/UVOT Finding Chart Observation
  24. GRB 090726: Swift-XRT position of probable counterpart
  25. GRB 090726: Swift detection of a burst
  26. Swift Trigger 358354 is not a GRB
  27. Konus-Wind and Konus-RF observations of GRB 090719
  28. Konus-RF and Konus-Wind observations of GRB 090718B
  29. Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
  30. Konus-Wind observations of bright hard GRB 090720B
  31. IPN Triangulation of bright GRB 090720B
  32. GRB 090720: Gemini-North Imaging and Optical Afterglow
  33. GRB 090720B: Fermi GBM detection
  34. Swift XRT and UVOT refned analysis of GRB 090720
  35. GRB 090709A: Swift XRT Timing Analysis
  36. GRB 090715B: VLA radio detection
  37. GRB 090720 Source found in ground processing of Swift-BAT data
  38. GRB 090717B: Fermi GBM detection
  39. GRB 090717: Fermi GBM detection
  40. GRB 090719: Fermi GBM detection
  41. GRB 090718B: Fermi GBM detection
  42. GRB 090718: Fermi GBM detection
  43. GRB 090720: Fermi GBM detection
  44. GRB 090715B: further NOT optical observations
  45. GRB 090715A: Suzaku WAM observation of the prompt emission
  46. GRB 090709A - CARMA mm Observations
  47. GRB 090715B: Lick observations
  48. GRB 090715A: VLA observations
  49. Konus-Wind observations of short/hard GRB 090715A
  50. GRB 090715B: MASTER optical limit
  51. GRB 090715A: Swift-BAT refined analysis
  52. Konus-Wind and Konus-RF observations of GRB 090715B
  53. GRB 090715B: Swift/UVOT followup observations
  54. GRB 090715B: break in the optical afterglow decay
  55. GRB 090715B: Enhanced Swift-XRT position
  56. GRB 090715B: Observation of the optical afterglow
  57. GRB 090715B: Swift XRT Refined Analysis
  58. GRB090715B: WHT redshift
  59. GRB 090715B: Swift-BAT refined analysis
  60. GRB 090715B: NOT optical observations
  61. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  62. Swift problem fixed
  63. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  64. GRB 090715A: ROTSE-III Optical Limits
  65. GRB 090715: Swift detection of a short hard burst
  66. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  67. Swift satellite anomaly
  68. GRB090713 optical limit by "Pi of the Sky"
  69. GRB 090712: Fermi GBM observation
  70. GRB 090713: Fermi GBM detection
  71. GRB 090712: Swift-BAT refined analysis
  72. GRB 090712: Swift detection of a burst
  73. GRB 090709A: Xinglong TNT optical upper limit
  74. VLA radio observations of GRB 090709A
  75. GRB 090621B: MTM-500 optical observations
  76. GRB 090709A: deep optical observation with the 10.4m GTC
  77. GRB090709A : WSRT Radio observation
  78. GRB 090709A: Suzaku WAM observation of the prompt emission
  79. GRB 090709A: Swift UVOT upper limits
  80. GRB 090709A: WHT LIRIS observations
  81. GRB 090709B: Fermi GBM detection
  82. GRB 090709A: confirmation of the periodicity in the SPI-ACS data
  83. GRB 090709A: evidence for a very red afterglow at low z
  84. Konus-Wind and Konus-RF observations of GRB 090709A
  85. GRB 090709A: P60 Observations
  86. GRB 090709A: Quasiperiodic variations in the BAT light curve
  87. GRB 090709A: NOT optical observations
  88. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  89. GRB 090709A: Swift XRT Refined Analysis
  90. GRB 090709B, Swift-BAT refined analysis
  91. GRB 090709A: Swift-BAT refined analysis
  92. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  93. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  94. GRB 090709A, RIMOTS optical upper limits
  95. GRB 090709A: Enhanced Swift-XRT position
  96. GRB 090709A - PAIRITEL Discovery of a Red Afterglow
  97. GRB 090709A: Subaru NIR observation
  98. GRB 090709B: Swift detection of a burst
  99. GRB 090709 : planned Suzaku-ToO observation
  100. GRB 090708 : Fermi GBM detection

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