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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 030824: Candidate Follow-Up
  2. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  3. IPN triangulation of GRB030827 (large error box)
  4. GRB 030823 observation at Ouda
  5. XRF030824: Second-epoch Palomar observations
  6. XRF030824: optical observations
  7. IPN triangulation of GRB030822 (annulus)
  8. GRB030823: optical observations
  9. GRB030823: Palomar observations
  10. XRF030824: Palomar observations
  11. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  12. GRB030823: optical observation at Tokyo Tech
  13. RAPTOR observations of GRB030823
  14. Lulin follow-up observations of GRB030823
  15. IPN triangulation of GRB030821 (=H2814; refined error box)
  16. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  17. Summary of recent IPN and HETE detections of SGR bursts
  18. IPN triangulation of GRB030814 (annulus)
  19. Clarification of GCN 2354 on SGR1806-20
  20. IPN detection of continued activity from SGR1806-20
  21. 030813 SGR event (Konus-Wind observation)
  22. GRB 030817 = H2808 TAROT optical observations
  23. SGR 1808-20 (=H2802): A Possible new SGR
  24. GRB 021206 Optical Observations
  25. IPN triangulation of GRB030808 (two large error boxes)
  26. IPN triangulation of GRB030806 (large burst; large error box)
  27. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  28. IPN/HETE summary of recent bursts from SGR1806-20
  29. XRF 030723: Detection of a rebrightening in the optical afterglow
  30. GRB030725: Optical observations
  31. XRF030723, BVRcIc field photometry update
  32. IPN triangulation of GRB030801 (large error box)
  33. GRB021206 optical counterpart upper limit
  34. IPN triangulation of GRB030731 (annulus)
  35. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  36. XRF030723: Re-analysis of ROTSE-III early images
  37. IPN triangulation of GRB030725 (=H2779; small error box)
  38. XRF030723 (=H2777): Second Epoch Magellan Observations
  39. GRB 030725: optical observations.
  40. GRB030725, optical transient observations
  41. IPN triangulation of GRB030726 (large error box)
  42. IPN triangulation of GRB030722 (large error box)
  43. IPN triangulation of GRB030721 (large error box)
  44. XRF030723 Radio Observations
  45. XRF 030723: confirmation of fading optical counterpart
  46. XRF030723(=H2777): Chandra Observations
  47. XRF 030723: VLT spectra
  48. Magellan Observations of XRF030723 (=H2777)
  49. GRB030723: Upper limits from historical observations
  50. GRB030725, possible optical transient
  51. XRF030723: Palomar observations and proposed counterpart
  52. GRB030725 (=H2779): A Bright GRB Localized by HETE
  53. XRF030723: optical observations
  54. XRF030723 (= H2777): Chandra Observations Scheduled
  55. XRF030723, BVRcIc field photometry correction
  56. XRF030723, ROTSE-III Early Observations
  57. XRF030723, BVRcIc field photometry
  58. XRF 030723, optical observations
  59. XRF030723, optical observations
  60. XRF 030723, optical observations
  61. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  62. GRB030723, optical observations
  63. Konus-Wind detection of the bursts from SGR1806-20 region
  64. IBAS GRB Alerts 969 970
  65. SGR 1806-20, submm observations
  66. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  67. IPN triangulation of GRB030717 (annulus)
  68. RXTE PCA Observations of SGR1806-20 Region
  69. GRB030329: Subaru Optical Spectroscopy
  70. Triangulation of GRB030715 (single large error box)
  71. Triangulation of GRB030714 (single large error box)
  72. 030716 NOT a GRB
  73. IPN triangulation of GRB030714 (two large error boxes)
  74. IPN triangulation of GRB030715 (two large error boxes)
  75. GRB030329: RTT150 optical observations
  76. GRBlog: Compilation of all GCN Circ. data
  77. IPN detection of renewed activity from SGR1806-20
  78. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  79. IPN triangulation of GRB030710 (annulus)
  80. IPN triangulation of GRB030709 (annulus)
  81. GRB030706 triangulation (single large error box)
  82. IPN triangulation of GRB030706 (annulus)
  83. IPN triangulation of GRB030629 (annulus)
  84. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  85. 030629 NOT a real GRB
  86. GRB030329, optical observation in May
  87. IPN triangulation of GRB030626 (single large error box)
  88. IPN triangulation of GRB030626 (two large error boxes)
  89. GRB030329: second XMM-Newton observation
  90. GRB030418: R optical observations
  91. HETE detection of burst from SGR1806-20
  92. GRB030329 -- RATAN-600 data in April-May
  93. Final IPN error ellipse for GRB021206 (the polarized GRB)
  94. GRB 021206, Radio afterglow candidate
  95. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  96. IPN triangulation of GRB030607 (annulus)
  97. IPN triangulation of GRB030606 (two alternate error boxes)
  98. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  99. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  100. IPN triangulation of GRB030605B (annulus)

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