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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 070621: TAROT Calern observatory optical observations
  2. GRB 070621: Watcher Observations
  3. GRB 070621: ROTSE-III Prompt Optical Limits
  4. GRB 070621: Swift detection of a burst
  5. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  6. GRB 070612A: TNG optical observations
  7. Swift/UVOT detection of GRB070616 optical afterglow.
  8. GRB070612A: Gemini Spectroscopic Redshift
  9. GRB 070612A: NOT observations
  10. GRB070616: Optical Observation by MITSuME Akeno
  11. GRB 070612B: Optical Observation by MITSuME Akeno
  12. GRB070616: Optical Observation by MITSuME Okayama
  13. GRB 070616, Swift-BAT further refined analysis
  14. GRB 070616: Swift XRT refined circular
  15. GRB 070612A: Possible WSRT Radio Detection
  16. GRB 070616: BTA astrometry and finding chart
  17. GRB 070616: BTA optical observations
  18. Swift/UVOT observations of GRB070616
  19. GRB 070616: TLS observation
  20. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  21. GRB 070616, Swift-BAT partial refined analysis
  22. GRB 070616: Swift detection of a burst
  23. GRB 070612B: optical observations
  24. UVOT Observations of INTEGRAL burst GRB070615
  25. VLA upper limit on GRB 070610
  26. GRB 070615
  27. GRB 070615: A long GRB detected by INTEGRAL
  28. SWIFT J195509.6+261406 (GRB 070610): further observations
  29. GRB 070612A: Super-LOTIS observations
  30. GRB 070612A: Rapid Decay
  31. GRB 070612A: Suzaku/WAM observation of the prompt emission
  32. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  33. GRB070612A: MITSuME Okayama Observation
  34. GRB 070612A: continued SARA observations
  35. GRB 070612A: spectral lag
  36. GRB 070611: Watcher Observations
  37. Swift Trigger 282176 is Cygnus X-1
  38. GRB 070612A: MDM Observations
  39. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  40. GRB 070612B: SARA upper limit
  41. GRB 070612B, Swift-BAT refined analysis
  42. GRB 070612A, Swift-BAT refined analysis
  43. GRB 070612B: Swift-XRT refined analysis
  44. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  45. GRB 070612B: Swift/UVOT upper limits
  46. GRB 070612B: FRAM limit
  47. GRB070612B: P60 Observations
  48. GRB 070612B: KAIT limits
  49. GRB 070612A: SARA detection of possible OT
  50. GRB 070612B: Swift XRT position from downlink data
  51. GRB 070610: TAROT Calern observatory optical observations
  52. GRB 070610: MITSuME OAO optical upper limit
  53. GRB 070612B: Swift detection of a burst
  54. GRB070612 - SDSS Pre-Burst Observations
  55. GRB 070612: Swift detection of a burst
  56. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  57. GRB 070610: SARA upper limit
  58. GRB 070610: Swift-XRT refined analysis
  59. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  60. GRB 070611: Swift/UVOT Observations
  61. GRB 070611: Swift-XRT refined analysis
  62. GRB 070611, Swift-BAT refined analysis
  63. GRB 070610: Optical observations from OSN
  64. GRB 070610: Watcher Observations
  65. GRB 070611: VLT redshift
  66. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  67. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  68. GRB 070611; Swift-XRT position
  69. GRB 070611: ROTSE-III Optical Limits
  70. GRB 070611: Swift detection of a burst
  71. GRB 070610: Swift-UVOT Upper Limits
  72. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  73. GRB 070610, Swift-BAT refined analysis
  74. GRB 070610; Swift-XRT position
  75. GRB 070610: Swift detection of a burst
  76. GRB 070412: TAROT Calern observatory optical observations
  77. GRB 070411: TAROT Calern observatory optical observations
  78. GRB 070419A, deep LBT photometry and possible supernova detection
  79. GRB070520B: optical observations
  80. GRB070520: optical observation
  81. GRB070518: optical observation
  82. GRB070521: optical observation
  83. Swift/UVOT refined analysis of GRB070531
  84. GRB 070531: NOT nIR observations
  85. GRB 070531: Swift-BAT refined analysis
  86. GRB 070531: I-band observations from IAC80
  87. GRB 070531: Swift-XRT position
  88. GRB 070531: Liverpool Telescope Optical Observations
  89. GRB 070531: Swift detection of a burst
  90. GRB 070529: SARA upper limit
  91. Swift/UVOT refined analysis of GRB070529
  92. GRB 070529: MARGE Observations
  93. GRB 070529: Optical aterglow from MIRO
  94. GRB 070529: Gemini Redshift
  95. GRB 070529: Swift-XRT refined analysis
  96. GRB 070529, Swift-BAT refined analysis
  97. GRB 070529: Xinglong TNT Optical Upper Limit
  98. GRB 070529: Swift detection of a burst with an optical aterglow
  99. GRB 070412: Deep Keck imaging
  100. Swift Triggers 280447, 280450 and 280451 are invalid

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