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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 ("Bastille"): Optical Pre-Imaging (Clarification)
  2. GRB 070714 ("Bastille"): Optical Pre-Imaging
  3. GRB 070714B, Swift-BAT refined analysis of the short hard burst
  4. GRB 070714A, Swift-BAT refined analysis
  5. GRB 070714 : Liverpool Telescope optical counterpart ?
  6. GRB 070714: Swift detection of a bright burst, possibly short
  7. Swift detection of a possible burst (Trigger 284850)
  8. SN 2007bg - off-axis GRB?
  9. GRB 070704: RTT150 optical observations
  10. GRB 070704: Suzaku/WAM observation of the prompt emission
  11. Konus-Wind observation of GRB 070707
  12. Updated Swift/UVOT calibration
  13. GRB 070707: optical afterglow
  14. GRB 070707: object inside XRT error circle
  15. Swift/UVOT Observations of GRB070707
  16. Swift XRT observation of GRB 070707
  17. GRB 070707: VLT observations
  18. INTEGRAL GRB 070707 is a short hard burst
  19. INTEGRAL GRB 070707 is a short hard burst
  20. GRB 070707: A long GRB detected by INTEGRAL
  21. GRB 070707: A long GRB detected by INTEGRAL
  22. GRB 070429B: NIR Observations
  23. GRB070704: FAVOR optical observations
  24. GRB 070704 : Liverpool Telescope Observations
  25. GRB 070611: VLT observations
  26. VLA detection of GRB 070612A in C Band
  27. Konus-Wind observation of GRB 070626
  28. GRB 070704: Swift-XRT refined analysis
  29. Swift/UVOT Observations of GRB070704
  30. GRB 070704, Swift-BAT refined analysis
  31. GRB 070704: Correction to GCN Circ 6594
  32. GRB 070704: Swift detection of a burst
  33. GRB 070626: Suzaku/WAM observation of the prompt emission
  34. GRB 070626: IPN localization and Konus spectrum of a bright long burst
  35. GRB 070628 Swift-UVOT Refined Analysis
  36. GRB 070628: NIR detection of afterglow
  37. GRB 070628, Swift-BAT refined analysis
  38. GRB 070628: TAROT La Silla observatory optical observations
  39. GRB 070628: Swift XRT refined analysis
  40. GRB 070628: Watcher Observations
  41. Swift UVOT Observations of GRB 070628
  42. GRB 070628: Swift detection of a possible burst
  43. GRB 070612A: Allen Telescope Array Observations
  44. IBAS Alert n. 4638: Not a GRB
  45. OT20050728 was not an optical GRB afterglow
  46. INTEGRAL burst GRB070615: X-ray continued observations
  47. GRB 070616 : WIDGET simultaneous optical observations
  48. GRB 070616: Suzaku/WAM observation of the prompt emission
  49. IBAS Alert n.4637: not a GRB
  50. GRB 070612A: Second Epoch WSRT Radio Observations
  51. GRB070621: RTT150 optical observations
  52. GRB 070621: VLT optical observations
  53. GRB 070621: Swift/UVOT Upper Limits
  54. Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
  55. GRB 070621: Swift-BAT refined analysis
  56. WHT observations of GRB070621
  57. GRB070621: Swift XRT refined analysis
  58. GRB 070621: Gemini South optical imaging
  59. GRB 070621: UVOT-enhanced XRT position
  60. Observations of GRB070612A at Calar Alto
  61. GRB 070621: NOT observations
  62. GRB070621: OPTIMA-Burst optical upper limit
  63. GRB 070621: TAROT Calern observatory optical observations
  64. GRB 070621: Watcher Observations
  65. GRB 070621: ROTSE-III Prompt Optical Limits
  66. GRB 070621: Swift detection of a burst
  67. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  68. GRB 070612A: TNG optical observations
  69. Swift/UVOT detection of GRB070616 optical afterglow.
  70. GRB070612A: Gemini Spectroscopic Redshift
  71. GRB 070612A: NOT observations
  72. GRB070616: Optical Observation by MITSuME Akeno
  73. GRB 070612B: Optical Observation by MITSuME Akeno
  74. GRB070616: Optical Observation by MITSuME Okayama
  75. GRB 070616, Swift-BAT further refined analysis
  76. GRB 070616: Swift XRT refined circular
  77. GRB 070612A: Possible WSRT Radio Detection
  78. GRB 070616: BTA astrometry and finding chart
  79. GRB 070616: BTA optical observations
  80. Swift/UVOT observations of GRB070616
  81. GRB 070616: TLS observation
  82. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  83. GRB 070616, Swift-BAT partial refined analysis
  84. GRB 070616: Swift detection of a burst
  85. GRB 070612B: optical observations
  86. UVOT Observations of INTEGRAL burst GRB070615
  87. VLA upper limit on GRB 070610
  88. GRB 070615
  89. GRB 070615: A long GRB detected by INTEGRAL
  90. SWIFT J195509.6+261406 (GRB 070610): further observations
  91. GRB 070612A: Super-LOTIS observations
  92. GRB 070612A: Rapid Decay
  93. GRB 070612A: Suzaku/WAM observation of the prompt emission
  94. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  95. GRB070612A: MITSuME Okayama Observation
  96. GRB 070612A: continued SARA observations
  97. GRB 070612A: spectral lag
  98. GRB 070611: Watcher Observations
  99. Swift Trigger 282176 is Cygnus X-1
  100. GRB 070612A: MDM Observations

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