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

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