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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 030913: ROTSE-3c Optical Observations
  2. GRB030913: OT's limit by MASTER
  3. GRB030921 triangulation (annulus)
  4. GRB030913, candidate afterglow observations
  5. GRB 030913, optical candidate
  6. GRB030913: AAVSO optical observations
  7. GRB 030913, BOOTES observations
  8. GRB030913 (=H2849): Confirmation of the Flight Localization
  9. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  10. GRB030913 (=H2849): TAROT Observations
  11. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  12. Magellan Observations of GRB030725 (=H2779)
  13. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  14. IPN triangulation of GRB030908 (annulus)
  15. GRB 030913: Optical limit at RIKEN
  16. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  17. XRF030824: Optical observations
  18. IPN triangulation of GRB030903 (large error box)
  19. IBAS detection of bursts from SGR 1806-20
  20. Radio Observations of SGR1806-20
  21. IPN triangulation of GRB030831 (annulus)
  22. IPN triangulation of GRB030830 (large error box)
  23. GRB 030824: Candidate Follow-Up
  24. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  25. IPN triangulation of GRB030827 (large error box)
  26. GRB 030823 observation at Ouda
  27. XRF030824: Second-epoch Palomar observations
  28. XRF030824: optical observations
  29. IPN triangulation of GRB030822 (annulus)
  30. GRB030823: optical observations
  31. GRB030823: Palomar observations
  32. XRF030824: Palomar observations
  33. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  34. GRB030823: optical observation at Tokyo Tech
  35. RAPTOR observations of GRB030823
  36. Lulin follow-up observations of GRB030823
  37. IPN triangulation of GRB030821 (=H2814; refined error box)
  38. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  39. Summary of recent IPN and HETE detections of SGR bursts
  40. IPN triangulation of GRB030814 (annulus)
  41. Clarification of GCN 2354 on SGR1806-20
  42. IPN detection of continued activity from SGR1806-20
  43. 030813 SGR event (Konus-Wind observation)
  44. GRB 030817 = H2808 TAROT optical observations
  45. SGR 1808-20 (=H2802): A Possible new SGR
  46. GRB 021206 Optical Observations
  47. IPN triangulation of GRB030808 (two large error boxes)
  48. IPN triangulation of GRB030806 (large burst; large error box)
  49. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  50. IPN/HETE summary of recent bursts from SGR1806-20
  51. XRF 030723: Detection of a rebrightening in the optical afterglow
  52. GRB030725: Optical observations
  53. XRF030723, BVRcIc field photometry update
  54. IPN triangulation of GRB030801 (large error box)
  55. GRB021206 optical counterpart upper limit
  56. IPN triangulation of GRB030731 (annulus)
  57. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  58. XRF030723: Re-analysis of ROTSE-III early images
  59. IPN triangulation of GRB030725 (=H2779; small error box)
  60. XRF030723 (=H2777): Second Epoch Magellan Observations
  61. GRB 030725: optical observations.
  62. GRB030725, optical transient observations
  63. IPN triangulation of GRB030726 (large error box)
  64. IPN triangulation of GRB030722 (large error box)
  65. IPN triangulation of GRB030721 (large error box)
  66. XRF030723 Radio Observations
  67. XRF 030723: confirmation of fading optical counterpart
  68. XRF030723(=H2777): Chandra Observations
  69. XRF 030723: VLT spectra
  70. Magellan Observations of XRF030723 (=H2777)
  71. GRB030723: Upper limits from historical observations
  72. GRB030725, possible optical transient
  73. XRF030723: Palomar observations and proposed counterpart
  74. GRB030725 (=H2779): A Bright GRB Localized by HETE
  75. XRF030723: optical observations
  76. XRF030723 (= H2777): Chandra Observations Scheduled
  77. XRF030723, BVRcIc field photometry correction
  78. XRF030723, ROTSE-III Early Observations
  79. XRF030723, BVRcIc field photometry
  80. XRF 030723, optical observations
  81. XRF030723, optical observations
  82. XRF 030723, optical observations
  83. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  84. GRB030723, optical observations
  85. Konus-Wind detection of the bursts from SGR1806-20 region
  86. IBAS GRB Alerts 969 970
  87. SGR 1806-20, submm observations
  88. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  89. IPN triangulation of GRB030717 (annulus)
  90. RXTE PCA Observations of SGR1806-20 Region
  91. GRB030329: Subaru Optical Spectroscopy
  92. Triangulation of GRB030715 (single large error box)
  93. Triangulation of GRB030714 (single large error box)
  94. 030716 NOT a GRB
  95. IPN triangulation of GRB030714 (two large error boxes)
  96. IPN triangulation of GRB030715 (two large error boxes)
  97. GRB030329: RTT150 optical observations
  98. GRBlog: Compilation of all GCN Circ. data
  99. IPN detection of renewed activity from SGR1806-20
  100. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)

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