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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"

20351 results found.

  1. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  2. GRB 090820: MASTER-Net optical polarization observations
  3. GRB 090817: optical upper limit
  4. GRB 090817: Confirmation of the X-ray afterglow
  5. GRB 090817: Swift/UVOT Upper Limits
  6. GRB 090817: Swift-XRT observations
  7. GRB 090814A: optical observations
  8. VLA radio non-detection of GRB 090812
  9. GRB 090813: CrAO optical obsevations
  10. GRB090814A: NOT optical follow-ups
  11. GRB 090814B: Swift/UVOT Upper Limits
  12. GRB 090814B: Swift-XRT detection of a possible afterglow.
  13. GRB 090814A: Swift/UVOT Observations
  14. GRB 090814A, RIMOTS optical upper limits
  15. GRB090814A: VLT spectroscopy
  16. GRB 090814: Enhanced Swift-XRT position
  17. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  18. GRB 090814: Swift detection of a burst
  19. GRB090813: Swift/UVOT upper limits
  20. GRB 090813: Enhanced Swift-XRT position
  21. GRB 090813: P60 Optical Afterglow Confirmation
  22. GRB 090813: Swift detection of a burst
  23. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  24. GRB 090812: RAPTOR detections during the burst
  25. GRB 090812, RIMOTS optical upper limits
  26. GRB 090812 Swift-BAT Refined Analysis
  27. GRB090812: Swift/UVOT observations
  28. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  29. GRB 090812: Enhanced Swift-XRT position
  30. GRB 090812: P60 Confirmation of Optical Afterglow
  31. GRB 090812: Swift detection of a burst with an optical counterpart
  32. GRB 090809: Further NOT optical observations
  33. VLA radio upper limit on GRB 090809
  34. GRB 090621B: MAGIC telescope GeV observation
  35. GRB 090809: WHT observations
  36. GRB090809: Swift/UVOT observations
  37. GRB 090809: Enhanced Swift-XRT position
  38. GRB 090809: afterglow confirmation at the NOT
  39. GRB 090809: Swift detection of a burst with a possible optical counterpart
  40. GRB 090807: MITSuME optical upper limit
  41. GRB 090807: Swift/UVOT Upper Limits
  42. GRB 090807: Enhanced Swift-XRT position
  43. GRB 090807, RIMOTS optical upper limits
  44. GRB 090807: Swift detection of a burst
  45. GRB 090726: optical observation
  46. Swift trigger 358760 is probably a noise event
  47. GRB 090727: GRT Optical Observation
  48. GRB 090728: Swift XRT refined analysis
  49. GRB 090726: GRT Optical Observation
  50. GRB 090727: Swift/UVOT Upper Limits
  51. GRB 090728: Swift/UVOT Upper Limits
  52. GRB 090728: Enhanced Swift-XRT position
  53. GRB 090728, RIMOTS optical upper limits
  54. GRB 090728: Swift detection of a burst
  55. GRB 090727: Enhanced Swift-XRT position
  56. GRB 090715B: Late-time Lick 3m observations
  57. GRB 090727: Swift detection of a burst
  58. GRB090726: Swift/UVOT observations
  59. GRB 090726: Enhanced Swift-XRT position
  60. GRB 090726: optical transient candidate
  61. Swift XRT and UVOT refned analysis of GRB 090720
  62. GRB 090715B: VLA radio detection
  63. GRB 090720 Source found in ground processing of Swift-BAT data
  64. GRB 090715B: further NOT optical observations
  65. GRB 090709A - CARMA mm Observations
  66. GRB 090715A: VLA observations
  67. GRB 090715B: Swift/UVOT followup observations
  68. GRB 090715B: Enhanced Swift-XRT position
  69. GRB 090715B: Observation of the optical afterglow
  70. GRB 090715B: NOT optical observations
  71. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  72. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  73. VLA radio observations of GRB 090709A
  74. GRB 090621B: MTM-500 optical observations
  75. GRB 090709A: deep optical observation with the 10.4m GTC
  76. GRB 090709A: Swift UVOT upper limits
  77. GRB 090709A: WHT LIRIS observations
  78. GRB 090709A: P60 Observations
  79. GRB 090709A: NOT optical observations
  80. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  81. GRB090709A: High Energy BAT/XRT Analysis Suggests Low to Moderate Redshift
  82. GRB 090709A: Wyoming Infrared Observatory NIR upper limits
  83. GRB 090709A, RIMOTS optical upper limits
  84. GRB 090709A: Enhanced Swift-XRT position
  85. GRB 090709A: Subaru NIR observation
  86. GRB 090709 : planned Suzaku-ToO observation
  87. GRB 090709: Faulkes Telescope North Upper Limits
  88. GRB 090709: PAIRITEL NIR Upper 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 090706: Fermi GBM detection
  93. GRB 090705: PAIRITEL NIR Observations
  94. GRB 090705: Swift detection of a possible burst
  95. XRF 090702 : RTT150 optical observations
  96. GRB 090529: CrAO optical upper limit
  97. GRB 090529: MTM-500 optical observations
  98. GRB 090702: UVOT upper limits
  99. XRF 090702: VLT imaging
  100. XRF 090702: Swift-XRT afterglow position

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