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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 070616: TLS observation
  2. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  3. GRB 070616, Swift-BAT partial refined analysis
  4. GRB 070616: Swift detection of a burst
  5. GRB 070612B: optical observations
  6. UVOT Observations of INTEGRAL burst GRB070615
  7. VLA upper limit on GRB 070610
  8. GRB 070615
  9. GRB 070615: A long GRB detected by INTEGRAL
  10. SWIFT J195509.6+261406 (GRB 070610): further observations
  11. GRB 070612A: Super-LOTIS observations
  12. GRB 070612A: Rapid Decay
  13. GRB 070612A: Suzaku/WAM observation of the prompt emission
  14. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  15. GRB070612A: MITSuME Okayama Observation
  16. GRB 070612A: continued SARA observations
  17. GRB 070612A: spectral lag
  18. GRB 070611: Watcher Observations
  19. Swift Trigger 282176 is Cygnus X-1
  20. GRB 070612A: MDM Observations
  21. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  22. GRB 070612B: SARA upper limit
  23. GRB 070612B, Swift-BAT refined analysis
  24. GRB 070612A, Swift-BAT refined analysis
  25. GRB 070612B: Swift-XRT refined analysis
  26. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  27. GRB 070612B: Swift/UVOT upper limits
  28. GRB 070612B: FRAM limit
  29. GRB070612B: P60 Observations
  30. GRB 070612B: KAIT limits
  31. GRB 070612A: SARA detection of possible OT
  32. GRB 070612B: Swift XRT position from downlink data
  33. GRB 070610: TAROT Calern observatory optical observations
  34. GRB 070610: MITSuME OAO optical upper limit
  35. GRB 070612B: Swift detection of a burst
  36. GRB070612 - SDSS Pre-Burst Observations
  37. GRB 070612: Swift detection of a burst
  38. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  39. GRB 070610: SARA upper limit
  40. GRB 070610: Swift-XRT refined analysis
  41. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  42. GRB 070611: Swift/UVOT Observations
  43. GRB 070611: Swift-XRT refined analysis
  44. GRB 070611, Swift-BAT refined analysis
  45. GRB 070610: Optical observations from OSN
  46. GRB 070610: Watcher Observations
  47. GRB 070611: VLT redshift
  48. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  49. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  50. GRB 070611; Swift-XRT position
  51. GRB 070611: ROTSE-III Optical Limits
  52. GRB 070611: Swift detection of a burst
  53. GRB 070610: Swift-UVOT Upper Limits
  54. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  55. GRB 070610, Swift-BAT refined analysis
  56. GRB 070610; Swift-XRT position
  57. GRB 070610: Swift detection of a burst
  58. GRB 070412: TAROT Calern observatory optical observations
  59. GRB 070411: TAROT Calern observatory optical observations
  60. GRB 070419A, deep LBT photometry and possible supernova detection
  61. GRB070520B: optical observations
  62. GRB070520: optical observation
  63. GRB070518: optical observation
  64. GRB070521: optical observation
  65. Swift/UVOT refined analysis of GRB070531
  66. GRB 070531: NOT nIR observations
  67. GRB 070531: Swift-BAT refined analysis
  68. GRB 070531: I-band observations from IAC80
  69. GRB 070531: Swift-XRT position
  70. GRB 070531: Liverpool Telescope Optical Observations
  71. GRB 070531: Swift detection of a burst
  72. GRB 070529: SARA upper limit
  73. Swift/UVOT refined analysis of GRB070529
  74. GRB 070529: MARGE Observations
  75. GRB 070529: Optical aterglow from MIRO
  76. GRB 070529: Gemini Redshift
  77. GRB 070529: Swift-XRT refined analysis
  78. GRB 070529, Swift-BAT refined analysis
  79. GRB 070529: Xinglong TNT Optical Upper Limit
  80. GRB 070529: Swift detection of a burst with an optical aterglow
  81. GRB 070412: Deep Keck imaging
  82. Swift Triggers 280447, 280450 and 280451 are invalid
  83. Swift trigger 280447 is probably a Galactic transient
  84. GRB 070518, deep LBT photometry
  85. GRB 070518: MARGE Observations
  86. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  87. Konus-Wind observation of GRB 070521
  88. GRB 070518: optical observation
  89. GRB070521: Second Epoch Gemini Imaging
  90. GRB070521: NIR observations
  91. GRB070520B: NIR observations
  92. GRB 070521: Swift/UVOT Upper Limits
  93. GRB 070521, optical observation
  94. GRB 070521: Swift-XRT refined analysis
  95. GRB 070521: Keck imaging
  96. GRB070521: Gemini Observations
  97. GROND upper limits of GRB 070521
  98. GRB 070521 Milagro GeV/TeV Observations
  99. GRB 070520B: SARA upper limit
  100. GRB 070520A: SARA upper limit

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