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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 070721B: Swift-XRT refined analysis
  2. GRB 070721A : Faulkes Telescope South optical limit
  3. GRB 070721A: Swift/XRT refined analysis
  4. GRB 070721B, Swift-BAT refined analysis
  5. GRB 070721A, Swift-BAT refined analysis
  6. GRB070721B: A bright UVOT candidate
  7. GRB 070721B: Swift detection of a burst
  8. GRB 070721: Swift detection of a possible burst
  9. GRB 070714B: Swift/BAT and Suzaku/WAM joint spectral analysis
  10. GRB 070714B : Suzaku WAM observation of the prompt emission
  11. GRB 070714A: Swift-BAT T_zero
  12. GRB070714B: TNG NIR observations
  13. Erratum : Suzaku WAM observation of GRB 070704
  14. GRB 070714A: Swift/UVOT Upper limits
  15. GRB 070714B: Swift/UVOT Upper Limits
  16. GRB 070714B: Swift-BAT spectral lag for the SHB
  17. GRB 070714B: confirmation of optical afterglow
  18. GRB 070616: No Evidence for I Band Afterglow
  19. GRB 070714A: Swift XRT refined analysis
  20. GRB070714B: Swift-XRT refined analysis
  21. GRB 070707: Swift-XRT follow-up observations
  22. GRB 070714b ("Bastille"): Optical Pre-Imaging (Clarification)
  23. GRB 070714 ("Bastille"): Optical Pre-Imaging
  24. GRB 070714B, Swift-BAT refined analysis of the short hard burst
  25. GRB 070714A, Swift-BAT refined analysis
  26. GRB 070714 : Liverpool Telescope optical counterpart ?
  27. GRB 070714: Swift detection of a bright burst, possibly short
  28. Swift detection of a possible burst (Trigger 284850)
  29. SN 2007bg - off-axis GRB?
  30. GRB 070704: RTT150 optical observations
  31. GRB 070704: Suzaku/WAM observation of the prompt emission
  32. Konus-Wind observation of GRB 070707
  33. Updated Swift/UVOT calibration
  34. GRB 070707: optical afterglow
  35. GRB 070707: object inside XRT error circle
  36. Swift/UVOT Observations of GRB070707
  37. Swift XRT observation of GRB 070707
  38. GRB 070707: VLT observations
  39. INTEGRAL GRB 070707 is a short hard burst
  40. INTEGRAL GRB 070707 is a short hard burst
  41. GRB 070707: A long GRB detected by INTEGRAL
  42. GRB 070707: A long GRB detected by INTEGRAL
  43. GRB 070429B: NIR Observations
  44. GRB070704: FAVOR optical observations
  45. GRB 070704 : Liverpool Telescope Observations
  46. GRB 070611: VLT observations
  47. VLA detection of GRB 070612A in C Band
  48. Konus-Wind observation of GRB 070626
  49. GRB 070704: Swift-XRT refined analysis
  50. Swift/UVOT Observations of GRB070704
  51. GRB 070704, Swift-BAT refined analysis
  52. GRB 070704: Correction to GCN Circ 6594
  53. GRB 070704: Swift detection of a burst
  54. GRB 070626: Suzaku/WAM observation of the prompt emission
  55. GRB 070626: IPN localization and Konus spectrum of a bright long burst
  56. GRB 070628 Swift-UVOT Refined Analysis
  57. GRB 070628: NIR detection of afterglow
  58. GRB 070628, Swift-BAT refined analysis
  59. GRB 070628: TAROT La Silla observatory optical observations
  60. GRB 070628: Swift XRT refined analysis
  61. GRB 070628: Watcher Observations
  62. Swift UVOT Observations of GRB 070628
  63. GRB 070628: Swift detection of a possible burst
  64. GRB 070612A: Allen Telescope Array Observations
  65. IBAS Alert n. 4638: Not a GRB
  66. OT20050728 was not an optical GRB afterglow
  67. INTEGRAL burst GRB070615: X-ray continued observations
  68. GRB 070616 : WIDGET simultaneous optical observations
  69. GRB 070616: Suzaku/WAM observation of the prompt emission
  70. IBAS Alert n.4637: not a GRB
  71. GRB 070612A: Second Epoch WSRT Radio Observations
  72. GRB070621: RTT150 optical observations
  73. GRB 070621: VLT optical observations
  74. GRB 070621: Swift/UVOT Upper Limits
  75. Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
  76. GRB 070621: Swift-BAT refined analysis
  77. WHT observations of GRB070621
  78. GRB070621: Swift XRT refined analysis
  79. GRB 070621: Gemini South optical imaging
  80. GRB 070621: UVOT-enhanced XRT position
  81. Observations of GRB070612A at Calar Alto
  82. GRB 070621: NOT observations
  83. GRB070621: OPTIMA-Burst optical upper limit
  84. GRB 070621: TAROT Calern observatory optical observations
  85. GRB 070621: Watcher Observations
  86. GRB 070621: ROTSE-III Prompt Optical Limits
  87. GRB 070621: Swift detection of a burst
  88. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  89. GRB 070612A: TNG optical observations
  90. Swift/UVOT detection of GRB070616 optical afterglow.
  91. GRB070612A: Gemini Spectroscopic Redshift
  92. GRB 070612A: NOT observations
  93. GRB070616: Optical Observation by MITSuME Akeno
  94. GRB 070612B: Optical Observation by MITSuME Akeno
  95. GRB070616: Optical Observation by MITSuME Okayama
  96. GRB 070616, Swift-BAT further refined analysis
  97. GRB 070616: Swift XRT refined circular
  98. GRB 070612A: Possible WSRT Radio Detection
  99. GRB 070616: BTA astrometry and finding chart
  100. GRB 070616: BTA optical observations

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