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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"

36135 results found.

  1. GRB030913: OT's limit by MASTER
  2. GRB030921 triangulation (annulus)
  3. GRB030913, candidate afterglow observations
  4. GRB 030913, optical candidate
  5. GRB 030913, BOOTES observations
  6. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  7. GRB030913 (=H2849): TAROT Observations
  8. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  9. Magellan Observations of GRB030725 (=H2779)
  10. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  11. IPN triangulation of GRB030908 (annulus)
  12. GRB 030913: Optical limit at RIKEN
  13. XRF030824: Optical observations
  14. IPN triangulation of GRB030903 (large error box)
  15. IPN triangulation of GRB030831 (annulus)
  16. IPN triangulation of GRB030830 (large error box)
  17. GRB 030824: Candidate Follow-Up
  18. IPN triangulation of GRB030827 (large error box)
  19. GRB 030823 observation at Ouda
  20. XRF030824: Second-epoch Palomar observations
  21. IPN triangulation of GRB030822 (annulus)
  22. GRB030823: Palomar observations
  23. XRF030824: Palomar observations
  24. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  25. IPN triangulation of GRB030821 (=H2814; refined error box)
  26. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  27. Summary of recent IPN and HETE detections of SGR bursts
  28. IPN triangulation of GRB030814 (annulus)
  29. IPN detection of continued activity from SGR1806-20
  30. 030813 SGR event (Konus-Wind observation)
  31. GRB 030817 = H2808 TAROT optical observations
  32. SGR 1808-20 (=H2802): A Possible new SGR
  33. GRB 021206 Optical Observations
  34. IPN triangulation of GRB030808 (two large error boxes)
  35. IPN triangulation of GRB030806 (large burst; large error box)
  36. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  37. IPN/HETE summary of recent bursts from SGR1806-20
  38. XRF 030723: Detection of a rebrightening in the optical afterglow
  39. GRB030725: Optical observations
  40. XRF030723, BVRcIc field photometry update
  41. IPN triangulation of GRB030801 (large error box)
  42. GRB021206 optical counterpart upper limit
  43. IPN triangulation of GRB030731 (annulus)
  44. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  45. IPN triangulation of GRB030725 (=H2779; small error box)
  46. XRF030723 (=H2777): Second Epoch Magellan Observations
  47. GRB 030725: optical observations.
  48. GRB030725, optical transient observations
  49. IPN triangulation of GRB030726 (large error box)
  50. IPN triangulation of GRB030722 (large error box)
  51. IPN triangulation of GRB030721 (large error box)
  52. XRF030723 Radio Observations
  53. XRF030723(=H2777): Chandra Observations
  54. Magellan Observations of XRF030723 (=H2777)
  55. GRB030723: Upper limits from historical observations
  56. GRB030725, possible optical transient
  57. XRF030723: Palomar observations and proposed counterpart
  58. GRB030725 (=H2779): A Bright GRB Localized by HETE
  59. XRF030723: optical observations
  60. XRF030723 (= H2777): Chandra Observations Scheduled
  61. XRF030723, BVRcIc field photometry
  62. XRF030723, optical observations
  63. GRB030723, optical observations
  64. IBAS GRB Alerts 969 970
  65. IPN triangulation of GRB030717 (annulus)
  66. GRB030329: Subaru Optical Spectroscopy
  67. Triangulation of GRB030715 (single large error box)
  68. Triangulation of GRB030714 (single large error box)
  69. 030716 NOT a GRB
  70. IPN triangulation of GRB030714 (two large error boxes)
  71. IPN triangulation of GRB030715 (two large error boxes)
  72. GRB030329: RTT150 optical observations
  73. GRBlog: Compilation of all GCN Circ. data
  74. IPN detection of renewed activity from SGR1806-20
  75. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  76. IPN triangulation of GRB030710 (annulus)
  77. IPN triangulation of GRB030709 (annulus)
  78. GRB030706 triangulation (single large error box)
  79. IPN triangulation of GRB030706 (annulus)
  80. IPN triangulation of GRB030629 (annulus)
  81. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  82. 030629 NOT a real GRB
  83. IPN triangulation of GRB030626 (single large error box)
  84. IPN triangulation of GRB030626 (two large error boxes)
  85. GRB030418: R optical observations
  86. GRB030329 -- RATAN-600 data in April-May
  87. Final IPN error ellipse for GRB021206 (the polarized GRB)
  88. GRB 021206, Radio afterglow candidate
  89. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  90. IPN triangulation of GRB030607 (annulus)
  91. IPN triangulation of GRB030606 (two alternate error boxes)
  92. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  93. IPN triangulation of GRB030605B (annulus)
  94. GRB 030528: Optical Observations
  95. IPN triangulation of GRB030605 (annulus)
  96. GRB 030528: tentative NIR counterpart
  97. GRB 030528, radio observations
  98. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  99. GRB030329, further radio observations at GMRT
  100. GRB030528, BVRI field photometry

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