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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. Swift XRT observation of GRB 070707
  2. GRB 070707: VLT observations
  3. INTEGRAL GRB 070707 is a short hard burst
  4. INTEGRAL GRB 070707 is a short hard burst
  5. GRB 070707: A long GRB detected by INTEGRAL
  6. GRB 070707: A long GRB detected by INTEGRAL
  7. GRB 070429B: NIR Observations
  8. GRB070704: FAVOR optical observations
  9. GRB 070704 : Liverpool Telescope Observations
  10. GRB 070611: VLT observations
  11. VLA detection of GRB 070612A in C Band
  12. Konus-Wind observation of GRB 070626
  13. GRB 070704: Swift-XRT refined analysis
  14. Swift/UVOT Observations of GRB070704
  15. GRB 070704, Swift-BAT refined analysis
  16. GRB 070704: Correction to GCN Circ 6594
  17. GRB 070704: Swift detection of a burst
  18. GRB 070626: Suzaku/WAM observation of the prompt emission
  19. GRB 070626: IPN localization and Konus spectrum of a bright long burst
  20. GRB 070628 Swift-UVOT Refined Analysis
  21. GRB 070628: NIR detection of afterglow
  22. GRB 070628, Swift-BAT refined analysis
  23. GRB 070628: TAROT La Silla observatory optical observations
  24. GRB 070628: Swift XRT refined analysis
  25. GRB 070628: Watcher Observations
  26. Swift UVOT Observations of GRB 070628
  27. GRB 070628: Swift detection of a possible burst
  28. GRB 070612A: Allen Telescope Array Observations
  29. IBAS Alert n. 4638: Not a GRB
  30. OT20050728 was not an optical GRB afterglow
  31. INTEGRAL burst GRB070615: X-ray continued observations
  32. GRB 070616 : WIDGET simultaneous optical observations
  33. GRB 070616: Suzaku/WAM observation of the prompt emission
  34. IBAS Alert n.4637: not a GRB
  35. GRB 070612A: Second Epoch WSRT Radio Observations
  36. GRB070621: RTT150 optical observations
  37. GRB 070621: VLT optical observations
  38. GRB 070621: Swift/UVOT Upper Limits
  39. Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
  40. GRB 070621: Swift-BAT refined analysis
  41. WHT observations of GRB070621
  42. GRB070621: Swift XRT refined analysis
  43. GRB 070621: Gemini South optical imaging
  44. GRB 070621: UVOT-enhanced XRT position
  45. Observations of GRB070612A at Calar Alto
  46. GRB 070621: NOT observations
  47. GRB070621: OPTIMA-Burst optical upper limit
  48. GRB 070621: TAROT Calern observatory optical observations
  49. GRB 070621: Watcher Observations
  50. GRB 070621: ROTSE-III Prompt Optical Limits
  51. GRB 070621: Swift detection of a burst
  52. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  53. GRB 070612A: TNG optical observations
  54. Swift/UVOT detection of GRB070616 optical afterglow.
  55. GRB070612A: Gemini Spectroscopic Redshift
  56. GRB 070612A: NOT observations
  57. GRB070616: Optical Observation by MITSuME Akeno
  58. GRB 070612B: Optical Observation by MITSuME Akeno
  59. GRB070616: Optical Observation by MITSuME Okayama
  60. GRB 070616, Swift-BAT further refined analysis
  61. GRB 070616: Swift XRT refined circular
  62. GRB 070612A: Possible WSRT Radio Detection
  63. GRB 070616: BTA astrometry and finding chart
  64. GRB 070616: BTA optical observations
  65. Swift/UVOT observations of GRB070616
  66. GRB 070616: TLS observation
  67. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  68. GRB 070616, Swift-BAT partial refined analysis
  69. GRB 070616: Swift detection of a burst
  70. GRB 070612B: optical observations
  71. UVOT Observations of INTEGRAL burst GRB070615
  72. VLA upper limit on GRB 070610
  73. GRB 070615
  74. GRB 070615: A long GRB detected by INTEGRAL
  75. SWIFT J195509.6+261406 (GRB 070610): further observations
  76. GRB 070612A: Super-LOTIS observations
  77. GRB 070612A: Rapid Decay
  78. GRB 070612A: Suzaku/WAM observation of the prompt emission
  79. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  80. GRB070612A: MITSuME Okayama Observation
  81. GRB 070612A: continued SARA observations
  82. GRB 070612A: spectral lag
  83. GRB 070611: Watcher Observations
  84. Swift Trigger 282176 is Cygnus X-1
  85. GRB 070612A: MDM Observations
  86. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  87. GRB 070612B: SARA upper limit
  88. GRB 070612B, Swift-BAT refined analysis
  89. GRB 070612A, Swift-BAT refined analysis
  90. GRB 070612B: Swift-XRT refined analysis
  91. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  92. GRB 070612B: Swift/UVOT upper limits
  93. GRB 070612B: FRAM limit
  94. GRB070612B: P60 Observations
  95. GRB 070612B: KAIT limits
  96. GRB 070612A: SARA detection of possible OT
  97. GRB 070612B: Swift XRT position from downlink data
  98. GRB 070610: TAROT Calern observatory optical observations
  99. GRB 070610: MITSuME OAO optical upper limit
  100. GRB 070612B: Swift detection of a burst

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