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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. GRB070616: Optical Observation by MITSuME Okayama
  2. GRB 070616, Swift-BAT further refined analysis
  3. GRB 070616: Swift XRT refined circular
  4. GRB 070612A: Possible WSRT Radio Detection
  5. GRB 070616: BTA astrometry and finding chart
  6. GRB 070616: BTA optical observations
  7. Swift/UVOT observations of GRB070616
  8. GRB 070616: TLS observation
  9. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  10. GRB 070616, Swift-BAT partial refined analysis
  11. GRB 070616: Swift detection of a burst
  12. GRB 070612B: optical observations
  13. UVOT Observations of INTEGRAL burst GRB070615
  14. VLA upper limit on GRB 070610
  15. GRB 070615
  16. GRB 070615: A long GRB detected by INTEGRAL
  17. SWIFT J195509.6+261406 (GRB 070610): further observations
  18. GRB 070612A: Super-LOTIS observations
  19. GRB 070612A: Rapid Decay
  20. GRB 070612A: Suzaku/WAM observation of the prompt emission
  21. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  22. GRB070612A: MITSuME Okayama Observation
  23. GRB 070612A: continued SARA observations
  24. GRB 070612A: spectral lag
  25. GRB 070611: Watcher Observations
  26. Swift Trigger 282176 is Cygnus X-1
  27. GRB 070612A: MDM Observations
  28. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  29. GRB 070612B: SARA upper limit
  30. GRB 070612B, Swift-BAT refined analysis
  31. GRB 070612A, Swift-BAT refined analysis
  32. GRB 070612B: Swift-XRT refined analysis
  33. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  34. GRB 070612B: Swift/UVOT upper limits
  35. GRB 070612B: FRAM limit
  36. GRB070612B: P60 Observations
  37. GRB 070612B: KAIT limits
  38. GRB 070612A: SARA detection of possible OT
  39. GRB 070612B: Swift XRT position from downlink data
  40. GRB 070610: TAROT Calern observatory optical observations
  41. GRB 070610: MITSuME OAO optical upper limit
  42. GRB 070612B: Swift detection of a burst
  43. GRB070612 - SDSS Pre-Burst Observations
  44. GRB 070612: Swift detection of a burst
  45. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  46. GRB 070610: SARA upper limit
  47. GRB 070610: Swift-XRT refined analysis
  48. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  49. GRB 070611: Swift/UVOT Observations
  50. GRB 070611: Swift-XRT refined analysis
  51. GRB 070611, Swift-BAT refined analysis
  52. GRB 070610: Optical observations from OSN
  53. GRB 070610: Watcher Observations
  54. GRB 070611: VLT redshift
  55. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  56. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  57. GRB 070611; Swift-XRT position
  58. GRB 070611: ROTSE-III Optical Limits
  59. GRB 070611: Swift detection of a burst
  60. GRB 070610: Swift-UVOT Upper Limits
  61. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  62. GRB 070610, Swift-BAT refined analysis
  63. GRB 070610; Swift-XRT position
  64. GRB 070610: Swift detection of a burst
  65. GRB 070412: TAROT Calern observatory optical observations
  66. GRB 070411: TAROT Calern observatory optical observations
  67. GRB 070419A, deep LBT photometry and possible supernova detection
  68. GRB070520B: optical observations
  69. GRB070520: optical observation
  70. GRB070518: optical observation
  71. GRB070521: optical observation
  72. Swift/UVOT refined analysis of GRB070531
  73. GRB 070531: NOT nIR observations
  74. GRB 070531: Swift-BAT refined analysis
  75. GRB 070531: I-band observations from IAC80
  76. GRB 070531: Swift-XRT position
  77. GRB 070531: Liverpool Telescope Optical Observations
  78. GRB 070531: Swift detection of a burst
  79. GRB 070529: SARA upper limit
  80. Swift/UVOT refined analysis of GRB070529
  81. GRB 070529: MARGE Observations
  82. GRB 070529: Optical aterglow from MIRO
  83. GRB 070529: Gemini Redshift
  84. GRB 070529: Swift-XRT refined analysis
  85. GRB 070529, Swift-BAT refined analysis
  86. GRB 070529: Xinglong TNT Optical Upper Limit
  87. GRB 070529: Swift detection of a burst with an optical aterglow
  88. GRB 070412: Deep Keck imaging
  89. Swift Triggers 280447, 280450 and 280451 are invalid
  90. Swift trigger 280447 is probably a Galactic transient
  91. GRB 070518, deep LBT photometry
  92. GRB 070518: MARGE Observations
  93. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  94. Konus-Wind observation of GRB 070521
  95. GRB 070518: optical observation
  96. GRB070521: Second Epoch Gemini Imaging
  97. GRB070521: NIR observations
  98. GRB070520B: NIR observations
  99. GRB 070521: Swift/UVOT Upper Limits
  100. GRB 070521, optical observation

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