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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 090711: Fermi GBM detection
  2. GRB090726: 6-meter telescope redshift
  3. GRB 090726: Swift-XRT Team refined analysis
  4. GRB 090726: Enhanced Swift-XRT position
  5. GRB 090726: optical transient candidate
  6. GRB 090726: Swift/UVOT Finding Chart Observation
  7. GRB 090726: Swift-XRT position of probable counterpart
  8. GRB 090726: Swift detection of a burst
  9. Swift Trigger 358354 is not a GRB
  10. Konus-Wind and Konus-RF observations of GRB 090719
  11. Konus-RF and Konus-Wind observations of GRB 090718B
  12. Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
  13. Konus-Wind observations of bright hard GRB 090720B
  14. IPN Triangulation of bright GRB 090720B
  15. GRB 090720: Gemini-North Imaging and Optical Afterglow
  16. GRB 090720B: Fermi GBM detection
  17. Swift XRT and UVOT refned analysis of GRB 090720
  18. GRB 090709A: Swift XRT Timing Analysis
  19. GRB 090715B: VLA radio detection
  20. GRB 090720 Source found in ground processing of Swift-BAT data
  21. GRB 090717B: Fermi GBM detection
  22. GRB 090717: Fermi GBM detection
  23. GRB 090719: Fermi GBM detection
  24. GRB 090718B: Fermi GBM detection
  25. GRB 090718: Fermi GBM detection
  26. GRB 090720: Fermi GBM detection
  27. GRB 090715B: further NOT optical observations
  28. GRB 090715A: Suzaku WAM observation of the prompt emission
  29. GRB 090709A - CARMA mm Observations
  30. GRB 090715B: Lick observations
  31. GRB 090715A: VLA observations
  32. Konus-Wind observations of short/hard GRB 090715A
  33. GRB 090715B: MASTER optical limit
  34. GRB 090715A: Swift-BAT refined analysis
  35. Konus-Wind and Konus-RF observations of GRB 090715B
  36. GRB 090715B: Swift/UVOT followup observations
  37. GRB 090715B: break in the optical afterglow decay
  38. GRB 090715B: Enhanced Swift-XRT position
  39. GRB 090715B: Observation of the optical afterglow
  40. GRB 090715B: Swift XRT Refined Analysis
  41. GRB090715B: WHT redshift
  42. GRB 090715B: Swift-BAT refined analysis
  43. GRB 090715B: NOT optical observations
  44. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  45. Swift problem fixed
  46. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  47. GRB 090715A: ROTSE-III Optical Limits
  48. GRB 090715: Swift detection of a short hard burst
  49. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  50. Swift satellite anomaly
  51. GRB090713 optical limit by "Pi of the Sky"
  52. GRB 090712: Fermi GBM observation
  53. GRB 090713: Fermi GBM detection
  54. GRB 090712: Swift-BAT refined analysis
  55. GRB 090712: Swift detection of a burst
  56. GRB 090709A: Xinglong TNT optical upper limit
  57. VLA radio observations of GRB 090709A
  58. GRB 090621B: MTM-500 optical observations
  59. GRB 090709A: deep optical observation with the 10.4m GTC
  60. GRB090709A : WSRT Radio observation
  61. GRB 090709A: Suzaku WAM observation of the prompt emission
  62. GRB 090709A: Swift UVOT upper limits
  63. GRB 090709A: WHT LIRIS observations
  64. GRB 090709B: Fermi GBM detection
  65. GRB 090709A: confirmation of the periodicity in the SPI-ACS data
  66. GRB 090709A: evidence for a very red afterglow at low z
  67. Konus-Wind and Konus-RF observations of GRB 090709A
  68. GRB 090709A: P60 Observations
  69. GRB 090709A: Quasiperiodic variations in the BAT light curve
  70. GRB 090709A: NOT optical observations
  71. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  72. GRB 090709A: Swift XRT Refined Analysis
  73. GRB 090709B, Swift-BAT refined analysis
  74. GRB 090709A: Swift-BAT refined analysis
  75. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  76. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  77. GRB 090709A, RIMOTS optical upper limits
  78. GRB 090709A: Enhanced Swift-XRT position
  79. GRB 090709A - PAIRITEL Discovery of a Red Afterglow
  80. GRB 090709A: Subaru NIR observation
  81. GRB 090709B: Swift detection of a burst
  82. GRB 090709 : planned Suzaku-ToO observation
  83. GRB 090708 : Fermi GBM detection
  84. GRB 090709: Faulkes Telescope North Upper Limits
  85. GRB 090626: Suzaku WAM observation of the prompt emission
  86. GRB 090709: PAIRITEL NIR Upper Limits
  87. GRB 090704: Fermi GBM observation
  88. GRB 090709: ROTSE-III Optical Limits
  89. GRB 090709: Swift detection of a bright burst
  90. GRB 090708: Early RAPTOR Optical Limits
  91. GRB 090708, Swift-BAT refined analysis
  92. GRB 090708: ROTSE-III Optical Limits
  93. GRB 090708: Swift detection of a burst
  94. GRB 090704: a long GRB found in INTEGRAL off-line analysis
  95. GRB 090706: Fermi GBM detection
  96. Swift-BAT trigger 356516 is not a GRB
  97. Possible GRB090705: Swift-XRT observations
  98. GRB 090705: PAIRITEL NIR Observations
  99. GRB 090705: Swift detection of a possible burst
  100. XRF 090702 : RTT150 optical observations

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