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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. GRB030913 (=H2849): Confirmation of the Flight Localization
  2. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  3. GRB030913 (=H2849): TAROT Observations
  4. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  5. Magellan Observations of GRB030725 (=H2779)
  6. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  7. IPN triangulation of GRB030908 (annulus)
  8. GRB 030913: Optical limit at RIKEN
  9. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  10. XRF030824: Optical observations
  11. IPN triangulation of GRB030903 (large error box)
  12. IBAS detection of bursts from SGR 1806-20
  13. Radio Observations of SGR1806-20
  14. IPN triangulation of GRB030831 (annulus)
  15. IPN triangulation of GRB030830 (large error box)
  16. GRB 030824: Candidate Follow-Up
  17. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  18. IPN triangulation of GRB030827 (large error box)
  19. GRB 030823 observation at Ouda
  20. XRF030824: Second-epoch Palomar observations
  21. XRF030824: optical observations
  22. IPN triangulation of GRB030822 (annulus)
  23. GRB030823: optical observations
  24. GRB030823: Palomar observations
  25. XRF030824: Palomar observations
  26. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  27. GRB030823: optical observation at Tokyo Tech
  28. RAPTOR observations of GRB030823
  29. Lulin follow-up observations of GRB030823
  30. IPN triangulation of GRB030821 (=H2814; refined error box)
  31. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  32. Summary of recent IPN and HETE detections of SGR bursts
  33. IPN triangulation of GRB030814 (annulus)
  34. Clarification of GCN 2354 on SGR1806-20
  35. IPN detection of continued activity from SGR1806-20
  36. 030813 SGR event (Konus-Wind observation)
  37. GRB 030817 = H2808 TAROT optical observations
  38. SGR 1808-20 (=H2802): A Possible new SGR
  39. GRB 021206 Optical Observations
  40. IPN triangulation of GRB030808 (two large error boxes)
  41. IPN triangulation of GRB030806 (large burst; large error box)
  42. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  43. IPN/HETE summary of recent bursts from SGR1806-20
  44. XRF 030723: Detection of a rebrightening in the optical afterglow
  45. GRB030725: Optical observations
  46. XRF030723, BVRcIc field photometry update
  47. IPN triangulation of GRB030801 (large error box)
  48. GRB021206 optical counterpart upper limit
  49. IPN triangulation of GRB030731 (annulus)
  50. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  51. XRF030723: Re-analysis of ROTSE-III early images
  52. IPN triangulation of GRB030725 (=H2779; small error box)
  53. XRF030723 (=H2777): Second Epoch Magellan Observations
  54. GRB 030725: optical observations.
  55. GRB030725, optical transient observations
  56. IPN triangulation of GRB030726 (large error box)
  57. IPN triangulation of GRB030722 (large error box)
  58. IPN triangulation of GRB030721 (large error box)
  59. XRF030723 Radio Observations
  60. XRF 030723: confirmation of fading optical counterpart
  61. XRF030723(=H2777): Chandra Observations
  62. XRF 030723: VLT spectra
  63. Magellan Observations of XRF030723 (=H2777)
  64. GRB030723: Upper limits from historical observations
  65. GRB030725, possible optical transient
  66. XRF030723: Palomar observations and proposed counterpart
  67. GRB030725 (=H2779): A Bright GRB Localized by HETE
  68. XRF030723: optical observations
  69. XRF030723 (= H2777): Chandra Observations Scheduled
  70. XRF030723, BVRcIc field photometry correction
  71. XRF030723, ROTSE-III Early Observations
  72. XRF030723, BVRcIc field photometry
  73. XRF 030723, optical observations
  74. XRF030723, optical observations
  75. XRF 030723, optical observations
  76. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  77. GRB030723, optical observations
  78. Konus-Wind detection of the bursts from SGR1806-20 region
  79. IBAS GRB Alerts 969 970
  80. SGR 1806-20, submm observations
  81. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  82. IPN triangulation of GRB030717 (annulus)
  83. RXTE PCA Observations of SGR1806-20 Region
  84. GRB030329: Subaru Optical Spectroscopy
  85. Triangulation of GRB030715 (single large error box)
  86. Triangulation of GRB030714 (single large error box)
  87. 030716 NOT a GRB
  88. IPN triangulation of GRB030714 (two large error boxes)
  89. IPN triangulation of GRB030715 (two large error boxes)
  90. GRB030329: RTT150 optical observations
  91. GRBlog: Compilation of all GCN Circ. data
  92. IPN detection of renewed activity from SGR1806-20
  93. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  94. IPN triangulation of GRB030710 (annulus)
  95. IPN triangulation of GRB030709 (annulus)
  96. GRB030706 triangulation (single large error box)
  97. IPN triangulation of GRB030706 (annulus)
  98. IPN triangulation of GRB030629 (annulus)
  99. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  100. 030629 NOT a real GRB

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