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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').
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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 030329: Planned XMM-Newton Observation
  2. IPN triangulation of GRB031120 (two large error boxes)
  3. GRB 031111B (= H2925) : Kyoto Optical Observation
  4. IPN/HETE localization of GRB031109 (=H2917; large error box)
  5. IPN detection of activity from SGR1806-20
  6. GRB 031111, Radio observations
  7. IPN triangulation of GRB031114 (large error box)
  8. IPN triangulation of GRB031107 (two large error boxes)
  9. GRB 031111: Optical observations
  10. GRB 031111, optical observations
  11. SN 2003jd (SN/GRB?) -- X-ray Observations
  12. HETE Prompt GRB Spectral Analyses
  13. IPN triangulation of GRB031111 (=H2924): small error box
  14. XRF031109 (=H2919): A very long XRF localized by HETE
  15. IPN triangulation of GRB031108 (large error box)
  16. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  17. GRB030929/SN2003jd association unlikely based on IPN localiztion
  18. IPN triangulation of GRB031027 (small error box)
  19. IPN triangulation of GRB031026B (large error box)
  20. Lulin optical follow-up observations of GRB031026
  21. SN 2003jd (SN/GRB?), Radio Observations
  22. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  23. GRB 031026: Further Ic Observations
  24. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  25. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  26. IPN triangulation of GRB031024 (single error box)
  27. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  28. GRB 031026: Ic Observations
  29. GRB031026 : KISO optical follow-up observation
  30. IPN triangulation of GRB031024 (annulus)
  31. IPN triangulation of GRB031020 (large error box)
  32. GRB030329: radio observations at RT-22 (CrAO)
  33. IPN triangulation of GRB031016 (two large error boxes)
  34. IBAS alert 1180 refers to a burst from SGR 1806-20
  35. HETE Prompt GRB Light Curves and Color-Color Diagrams
  36. IPN triangulation of GRB031014 (annulus)
  37. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  38. XRF 030824: additional observations at CFHT
  39. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  40. IPN triangulation of GRB031008 (annulus)
  41. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  42. IPN detection of continued activity from SGR1806-20
  43. IPN triangulation of GRB031007 (two large error boxes)
  44. XRF 030723: Subaru Optical Observations
  45. IPN triangulation of GRB031004B (annulus)
  46. IPN triangulation of GRB031004A (short/hard; annulus)
  47. IPN triangulation of GRB030929 (short/hard; annulus)
  48. A burst from SGR 1806-20 detected with IBAS
  49. XRF 030824: Early follow-up observation at Kiso observatory
  50. XRF 030824: observations at CFHT
  51. IPN triangulation of GRB030926 (short/hard; large error box)
  52. IPN triangulation of GRB030922B (large error box)
  53. XRF 030723: Detection of the likely host galaxy
  54. XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
  55. XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
  56. IPN triangulation of GRB030922A (large error box)
  57. IPN triangulation of GRB030921 (large error box)
  58. IPN triangulation of GRB030919 (large error box)
  59. GRB030922 triangulation (annulus)
  60. GRB030913: Subaru Optical Observations
  61. GRB 030913: ROTSE-3c Optical Observations
  62. GRB030913: OT's limit by MASTER
  63. GRB030921 triangulation (annulus)
  64. GRB030913, candidate afterglow observations
  65. GRB 030913, optical candidate
  66. GRB030913: AAVSO optical observations
  67. GRB 030913, BOOTES observations
  68. GRB030913 (=H2849): Confirmation of the Flight Localization
  69. IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
  70. GRB030913 (=H2849): TAROT Observations
  71. GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
  72. Magellan Observations of GRB030725 (=H2779)
  73. GRB030913 (=H2849): A GRB Possibly Localized by HETE
  74. IPN triangulation of GRB030908 (annulus)
  75. GRB 030913: Optical limit at RIKEN
  76. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  77. XRF030824: Optical observations
  78. IPN triangulation of GRB030903 (large error box)
  79. IBAS detection of bursts from SGR 1806-20
  80. Radio Observations of SGR1806-20
  81. IPN triangulation of GRB030831 (annulus)
  82. IPN triangulation of GRB030830 (large error box)
  83. GRB 030824: Candidate Follow-Up
  84. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  85. IPN triangulation of GRB030827 (large error box)
  86. GRB 030823 observation at Ouda
  87. XRF030824: Second-epoch Palomar observations
  88. XRF030824: optical observations
  89. IPN triangulation of GRB030822 (annulus)
  90. GRB030823: optical observations
  91. GRB030823: Palomar observations
  92. XRF030824: Palomar observations
  93. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  94. GRB030823: optical observation at Tokyo Tech
  95. RAPTOR observations of GRB030823
  96. Lulin follow-up observations of GRB030823
  97. IPN triangulation of GRB030821 (=H2814; refined error box)
  98. GRB 030821(=H2814): A Faint, Long GRB Localized by the HETE WXM and the IPN
  99. Summary of recent IPN and HETE detections of SGR bursts
  100. IPN triangulation of GRB030814 (annulus)

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