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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. HETE 2493: Optical observations
  2. HETE 2493: Optical candidate
  3. GRB 021204: Optical Observations at RIKEN
  4. GRB 021125: Radio Observations
  5. IPN triangulation of GRB021206 (small error box)
  6. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  7. IPN detection of renewed activity from SGR1806-20
  8. IPN triangulation of GRB021205 (large error box)
  9. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  10. GRB021201, BVRcIc field photometry
  11. GRB 021201, Radio Observations
  12. GRB 021201: Optical Observations
  13. GRB 021201: BOOTES simultaneous optical observations
  14. IPN triangulation of GRB021201 (short/hard burst, small error box)
  15. Radio Catalog of GRB Afterglows
  16. GRB021004, late time optical observations
  17. GRB021004 Chandra Observation
  18. IPN detection of continued SGR1900+14 activity
  19. GRB021125 refined position
  20. IPN triangulation of GRB021115 (annulus)
  21. IPN triangulation of GRB021125B (two large error boxes)
  22. IPN triangulation of GRB021119 (large error box)
  23. IPN triangulation of GRB021125B (annulus)
  24. Improved IPN error box for GRB021125
  25. IPN BURST POSITION
  26. IPN triangulation of GRB021125 (INTEGRAL BURST)
  27. GRB021125 : A long GRB localized by INTEGRAL
  28. IPN confirmation of the reactivation of SGR1900+14
  29. IPN detection of possible reactivation of SGR1900+14
  30. GRB021113, SPI ACS observation
  31. IPN triangulation of GRB021119 (annulus)
  32. GRB 021112: Afterglow or Variable Star?
  33. GRB021113: optical observations at Bisei
  34. GRB 021113: Evidence for a Dark Optical Afterglow
  35. GRB 021112, Radio Observations
  36. GRB021112, BVRI field photometry
  37. GRB 021112: Variable Source in R-band search
  38. GRB021112: Optical Observations
  39. GRB021113: Kiso Observations
  40. IPN triangulation of GRB021109 (portion of annulus)
  41. IPN triangulation of GRB021113 (=H2449; annulus)
  42. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  43. GRB 021113: Optical observations
  44. GRB 021112: RAPTOR Observations
  45. GRB 021113: Optical Observations
  46. GRB 021113: Optical Observations
  47. GRB021113 (=H2449): A Long GRB Localized by HETE
  48. GRB 021112: Optical Observations
  49. GRB 021112: R-band search
  50. IPN triangulation of GRB021108 (large error box)
  51. GRB021112 (=H2448): A Long GRB Localized by HETE
  52. GRB 021016: Optical Observations
  53. IPN triangulation of GRB021109 (annulus)
  54. IPN triangulation of GRB021108 (annulus)
  55. GRB021004: Near infrared spectroscopy
  56. GRB021104: Optical Observations
  57. IPN triangulation of GRB021104 (annulus)
  58. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  59. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  60. SGR1900+14 activity, November 2-4, 2002
  61. Spectropolarimetry of GRB021004
  62. GRB021104: Optical observations
  63. GRB021104: optical observations
  64. GRB021104: Candidate present in DSS
  65. GRB021104: possible optical afterglow
  66. IPN triangulation of GRB021102 (annulus)
  67. Detection of activity from SGR 1900+14 with the RXTE/PCA
  68. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  69. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  70. IPN triangulation of GRB021025 (portion of annulus)
  71. IPN triangulation of GRB021027 (single large error box)
  72. GRB021004, late-time optical observations
  73. IPN triangulation of GRB021027 (two large error boxes)
  74. GRB 021023: Infrared Imaging
  75. IPN triangulation of GRB021027 (annulus)
  76. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  77. IPN triangulation of GRB021025 (annulus)
  78. IPN triangulation of SGR1900+14, October 22 2002
  79. GRB 021004: optical observations
  80. IPN triangulation of GRB021023 (small error boc)
  81. GRB021004: Optical Observations
  82. GRB 020813; likely host galaxy.
  83. IPN triangulation of GRB021020 (smaller error box)
  84. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  85. IPN triangulation of GRB021020
  86. GRB 021008, radio observations
  87. GRB 021016, optical observations
  88. GRB 021004: VRI observations at TNG: possible break
  89. GRB021016, optical observations
  90. SGR1900+14: burst on October 10 2002
  91. GRB 021008, optical observations
  92. GRB021016(=H2397): A Long GRB Localized by HETE
  93. IPN triangulation of GRB021016 (area corrected)
  94. IPN triangulation of GRB021016 (small error box)
  95. GRB021004: Optical Observations
  96. IPN triangulation of GRB021014 (large error box)
  97. IPN triangulation of GRB021013 (single error box)
  98. GRB 021004: optical spectroscopy on Oct 11
  99. IPN triangulation of GRB021013 (two small error boxes)
  100. GRB021004: High-resolution optical spectroscopy

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