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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 070628: TAROT La Silla observatory optical observations
  2. GRB 070628: Swift XRT refined analysis
  3. GRB 070628: Watcher Observations
  4. Swift UVOT Observations of GRB 070628
  5. GRB 070628: Swift detection of a possible burst
  6. GRB 070612A: Allen Telescope Array Observations
  7. IBAS Alert n. 4638: Not a GRB
  8. OT20050728 was not an optical GRB afterglow
  9. INTEGRAL burst GRB070615: X-ray continued observations
  10. GRB 070616 : WIDGET simultaneous optical observations
  11. GRB 070616: Suzaku/WAM observation of the prompt emission
  12. IBAS Alert n.4637: not a GRB
  13. GRB 070612A: Second Epoch WSRT Radio Observations
  14. GRB070621: RTT150 optical observations
  15. GRB 070621: VLT optical observations
  16. GRB 070621: Swift/UVOT Upper Limits
  17. Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
  18. GRB 070621: Swift-BAT refined analysis
  19. WHT observations of GRB070621
  20. GRB070621: Swift XRT refined analysis
  21. GRB 070621: Gemini South optical imaging
  22. GRB 070621: UVOT-enhanced XRT position
  23. Observations of GRB070612A at Calar Alto
  24. GRB 070621: NOT observations
  25. GRB070621: OPTIMA-Burst optical upper limit
  26. GRB 070621: TAROT Calern observatory optical observations
  27. GRB 070621: Watcher Observations
  28. GRB 070621: ROTSE-III Prompt Optical Limits
  29. GRB 070621: Swift detection of a burst
  30. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  31. GRB 070612A: TNG optical observations
  32. Swift/UVOT detection of GRB070616 optical afterglow.
  33. GRB070612A: Gemini Spectroscopic Redshift
  34. GRB 070612A: NOT observations
  35. GRB070616: Optical Observation by MITSuME Akeno
  36. GRB 070612B: Optical Observation by MITSuME Akeno
  37. GRB070616: Optical Observation by MITSuME Okayama
  38. GRB 070616, Swift-BAT further refined analysis
  39. GRB 070616: Swift XRT refined circular
  40. GRB 070612A: Possible WSRT Radio Detection
  41. GRB 070616: BTA astrometry and finding chart
  42. GRB 070616: BTA optical observations
  43. Swift/UVOT observations of GRB070616
  44. GRB 070616: TLS observation
  45. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  46. GRB 070616, Swift-BAT partial refined analysis
  47. GRB 070616: Swift detection of a burst
  48. GRB 070612B: optical observations
  49. UVOT Observations of INTEGRAL burst GRB070615
  50. VLA upper limit on GRB 070610
  51. GRB 070615
  52. GRB 070615: A long GRB detected by INTEGRAL
  53. SWIFT J195509.6+261406 (GRB 070610): further observations
  54. GRB 070612A: Super-LOTIS observations
  55. GRB 070612A: Rapid Decay
  56. GRB 070612A: Suzaku/WAM observation of the prompt emission
  57. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  58. GRB070612A: MITSuME Okayama Observation
  59. GRB 070612A: continued SARA observations
  60. GRB 070612A: spectral lag
  61. GRB 070611: Watcher Observations
  62. Swift Trigger 282176 is Cygnus X-1
  63. GRB 070612A: MDM Observations
  64. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  65. GRB 070612B: SARA upper limit
  66. GRB 070612B, Swift-BAT refined analysis
  67. GRB 070612A, Swift-BAT refined analysis
  68. GRB 070612B: Swift-XRT refined analysis
  69. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  70. GRB 070612B: Swift/UVOT upper limits
  71. GRB 070612B: FRAM limit
  72. GRB070612B: P60 Observations
  73. GRB 070612B: KAIT limits
  74. GRB 070612A: SARA detection of possible OT
  75. GRB 070612B: Swift XRT position from downlink data
  76. GRB 070610: TAROT Calern observatory optical observations
  77. GRB 070610: MITSuME OAO optical upper limit
  78. GRB 070612B: Swift detection of a burst
  79. GRB070612 - SDSS Pre-Burst Observations
  80. GRB 070612: Swift detection of a burst
  81. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  82. GRB 070610: SARA upper limit
  83. GRB 070610: Swift-XRT refined analysis
  84. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  85. GRB 070611: Swift/UVOT Observations
  86. GRB 070611: Swift-XRT refined analysis
  87. GRB 070611, Swift-BAT refined analysis
  88. GRB 070610: Optical observations from OSN
  89. GRB 070610: Watcher Observations
  90. GRB 070611: VLT redshift
  91. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  92. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  93. GRB 070611; Swift-XRT position
  94. GRB 070611: ROTSE-III Optical Limits
  95. GRB 070611: Swift detection of a burst
  96. GRB 070610: Swift-UVOT Upper Limits
  97. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  98. GRB 070610, Swift-BAT refined analysis
  99. GRB 070610; Swift-XRT position
  100. GRB 070610: Swift detection of a burst

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