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

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