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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. IPN triangulation of GRB030903 (large error box)
  2. IBAS detection of bursts from SGR 1806-20
  3. Radio Observations of SGR1806-20
  4. IPN triangulation of GRB030831 (annulus)
  5. IPN triangulation of GRB030830 (large error box)
  6. GRB 030824: Candidate Follow-Up
  7. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  8. IPN triangulation of GRB030827 (large error box)
  9. GRB 030823 observation at Ouda
  10. XRF030824: Second-epoch Palomar observations
  11. XRF030824: optical observations
  12. IPN triangulation of GRB030822 (annulus)
  13. GRB030823: optical observations
  14. GRB030823: Palomar observations
  15. XRF030824: Palomar observations
  16. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  17. GRB030823: optical observation at Tokyo Tech
  18. RAPTOR observations of GRB030823
  19. Lulin follow-up observations of GRB030823
  20. IPN triangulation of GRB030821 (=H2814; refined error box)
  21. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  22. Summary of recent IPN and HETE detections of SGR bursts
  23. IPN triangulation of GRB030814 (annulus)
  24. Clarification of GCN 2354 on SGR1806-20
  25. IPN detection of continued activity from SGR1806-20
  26. 030813 SGR event (Konus-Wind observation)
  27. GRB 030817 = H2808 TAROT optical observations
  28. SGR 1808-20 (=H2802): A Possible new SGR
  29. GRB 021206 Optical Observations
  30. IPN triangulation of GRB030808 (two large error boxes)
  31. IPN triangulation of GRB030806 (large burst; large error box)
  32. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  33. IPN/HETE summary of recent bursts from SGR1806-20
  34. XRF 030723: Detection of a rebrightening in the optical afterglow
  35. GRB030725: Optical observations
  36. XRF030723, BVRcIc field photometry update
  37. IPN triangulation of GRB030801 (large error box)
  38. GRB021206 optical counterpart upper limit
  39. IPN triangulation of GRB030731 (annulus)
  40. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  41. XRF030723: Re-analysis of ROTSE-III early images
  42. IPN triangulation of GRB030725 (=H2779; small error box)
  43. XRF030723 (=H2777): Second Epoch Magellan Observations
  44. GRB 030725: optical observations.
  45. GRB030725, optical transient observations
  46. IPN triangulation of GRB030726 (large error box)
  47. IPN triangulation of GRB030722 (large error box)
  48. IPN triangulation of GRB030721 (large error box)
  49. XRF030723 Radio Observations
  50. XRF 030723: confirmation of fading optical counterpart
  51. XRF030723(=H2777): Chandra Observations
  52. XRF 030723: VLT spectra
  53. Magellan Observations of XRF030723 (=H2777)
  54. GRB030723: Upper limits from historical observations
  55. GRB030725, possible optical transient
  56. XRF030723: Palomar observations and proposed counterpart
  57. GRB030725 (=H2779): A Bright GRB Localized by HETE
  58. XRF030723: optical observations
  59. XRF030723 (= H2777): Chandra Observations Scheduled
  60. XRF030723, BVRcIc field photometry correction
  61. XRF030723, ROTSE-III Early Observations
  62. XRF030723, BVRcIc field photometry
  63. XRF 030723, optical observations
  64. XRF030723, optical observations
  65. XRF 030723, optical observations
  66. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  67. GRB030723, optical observations
  68. Konus-Wind detection of the bursts from SGR1806-20 region
  69. IBAS GRB Alerts 969 970
  70. SGR 1806-20, submm observations
  71. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  72. IPN triangulation of GRB030717 (annulus)
  73. RXTE PCA Observations of SGR1806-20 Region
  74. GRB030329: Subaru Optical Spectroscopy
  75. Triangulation of GRB030715 (single large error box)
  76. Triangulation of GRB030714 (single large error box)
  77. 030716 NOT a GRB
  78. IPN triangulation of GRB030714 (two large error boxes)
  79. IPN triangulation of GRB030715 (two large error boxes)
  80. GRB030329: RTT150 optical observations
  81. GRBlog: Compilation of all GCN Circ. data
  82. IPN detection of renewed activity from SGR1806-20
  83. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  84. IPN triangulation of GRB030710 (annulus)
  85. IPN triangulation of GRB030709 (annulus)
  86. GRB030706 triangulation (single large error box)
  87. IPN triangulation of GRB030706 (annulus)
  88. IPN triangulation of GRB030629 (annulus)
  89. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  90. 030629 NOT a real GRB
  91. GRB030329, optical observation in May
  92. IPN triangulation of GRB030626 (single large error box)
  93. IPN triangulation of GRB030626 (two large error boxes)
  94. GRB030329: second XMM-Newton observation
  95. GRB030418: R optical observations
  96. HETE detection of burst from SGR1806-20
  97. GRB030329 -- RATAN-600 data in April-May
  98. Final IPN error ellipse for GRB021206 (the polarized GRB)
  99. GRB 021206, Radio afterglow candidate
  100. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch

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