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

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