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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. XRF030824: Palomar observations
  2. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  3. GRB030823: optical observation at Tokyo Tech
  4. RAPTOR observations of GRB030823
  5. Lulin follow-up observations of GRB030823
  6. IPN triangulation of GRB030821 (=H2814; refined error box)
  7. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  8. Summary of recent IPN and HETE detections of SGR bursts
  9. IPN triangulation of GRB030814 (annulus)
  10. Clarification of GCN 2354 on SGR1806-20
  11. IPN detection of continued activity from SGR1806-20
  12. 030813 SGR event (Konus-Wind observation)
  13. GRB 030817 = H2808 TAROT optical observations
  14. SGR 1808-20 (=H2802): A Possible new SGR
  15. GRB 021206 Optical Observations
  16. IPN triangulation of GRB030808 (two large error boxes)
  17. IPN triangulation of GRB030806 (large burst; large error box)
  18. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  19. IPN/HETE summary of recent bursts from SGR1806-20
  20. XRF 030723: Detection of a rebrightening in the optical afterglow
  21. GRB030725: Optical observations
  22. XRF030723, BVRcIc field photometry update
  23. IPN triangulation of GRB030801 (large error box)
  24. GRB021206 optical counterpart upper limit
  25. IPN triangulation of GRB030731 (annulus)
  26. IBAS GRB Alerts 1011-1017 NOT CONFIRMED
  27. XRF030723: Re-analysis of ROTSE-III early images
  28. IPN triangulation of GRB030725 (=H2779; small error box)
  29. XRF030723 (=H2777): Second Epoch Magellan Observations
  30. GRB 030725: optical observations.
  31. GRB030725, optical transient observations
  32. IPN triangulation of GRB030726 (large error box)
  33. IPN triangulation of GRB030722 (large error box)
  34. IPN triangulation of GRB030721 (large error box)
  35. XRF030723 Radio Observations
  36. XRF 030723: confirmation of fading optical counterpart
  37. XRF030723(=H2777): Chandra Observations
  38. XRF 030723: VLT spectra
  39. Magellan Observations of XRF030723 (=H2777)
  40. GRB030723: Upper limits from historical observations
  41. GRB030725, possible optical transient
  42. XRF030723: Palomar observations and proposed counterpart
  43. GRB030725 (=H2779): A Bright GRB Localized by HETE
  44. XRF030723: optical observations
  45. XRF030723 (= H2777): Chandra Observations Scheduled
  46. XRF030723, BVRcIc field photometry correction
  47. XRF030723, ROTSE-III Early Observations
  48. XRF030723, BVRcIc field photometry
  49. XRF 030723, optical observations
  50. XRF030723, optical observations
  51. XRF 030723, optical observations
  52. XRF030723 (=H2777): An X-ray Flash Localized by the HETE WXM and
  53. GRB030723, optical observations
  54. Konus-Wind detection of the bursts from SGR1806-20 region
  55. IBAS GRB Alerts 969 970
  56. SGR 1806-20, submm observations
  57. H2768, H2770, and H2771: Three Bursts from SGR1806-20
  58. IPN triangulation of GRB030717 (annulus)
  59. RXTE PCA Observations of SGR1806-20 Region
  60. GRB030329: Subaru Optical Spectroscopy
  61. Triangulation of GRB030715 (single large error box)
  62. Triangulation of GRB030714 (single large error box)
  63. 030716 NOT a GRB
  64. IPN triangulation of GRB030714 (two large error boxes)
  65. IPN triangulation of GRB030715 (two large error boxes)
  66. GRB030329: RTT150 optical observations
  67. GRBlog: Compilation of all GCN Circ. data
  68. IPN detection of renewed activity from SGR1806-20
  69. IPN triangulation of GRB030711 (annulus, =SGR0525-66?)
  70. IPN triangulation of GRB030710 (annulus)
  71. IPN triangulation of GRB030709 (annulus)
  72. GRB030706 triangulation (single large error box)
  73. IPN triangulation of GRB030706 (annulus)
  74. IPN triangulation of GRB030629 (annulus)
  75. GRB030629 triangulation (Konus-Wind -- Helicon annulus)
  76. 030629 NOT a real GRB
  77. GRB030329, optical observation in May
  78. IPN triangulation of GRB030626 (single large error box)
  79. IPN triangulation of GRB030626 (two large error boxes)
  80. GRB030329: second XMM-Newton observation
  81. GRB030418: R optical observations
  82. HETE detection of burst from SGR1806-20
  83. GRB030329 -- RATAN-600 data in April-May
  84. Final IPN error ellipse for GRB021206 (the polarized GRB)
  85. GRB 021206, Radio afterglow candidate
  86. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  87. IPN triangulation of GRB030607 (annulus)
  88. IPN triangulation of GRB030606 (two alternate error boxes)
  89. GRB030329, SPM optical observations (Correction of GCN2075 R band)
  90. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  91. IPN triangulation of GRB030605B (annulus)
  92. GRB 030528: Optical Observations
  93. IPN triangulation of GRB030605 (annulus)
  94. GRB 030528: tentative NIR counterpart
  95. GRB 030528, radio observations
  96. GRB030528(=H2724): Observations with the Chandra X-ray Observatory
  97. GRB030329, further radio observations at GMRT
  98. GRB030528, BVRI field photometry
  99. IPN triangulation of GRB030601 (annulus)
  100. GRB030329, SPM optical observations

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