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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 021211: Probable Host and Underlying Supernova
  2. GRB 021226 registration by Helicon/Coronas-F
  3. Probable GRB in INTEGRAL SPI-ACS
  4. IPN triangulation of GRB021223 (two large error boxes)
  5. GRB021211, radio observations
  6. GRB 021112: Evidence for Another Dark Optical Afterglow
  7. GRB 021219: OSN optical observations
  8. GRB021219: Radio Observations
  9. GRB021219, optical observations
  10. IPN triangulation of GRB021219 - CORRECTION
  11. IPN triangulation of GRB021219
  12. GRB021219, optical observation by MASTER
  13. GRB021219: Correction to GCN 1766
  14. GRB021219 refined position with INTEGRAL
  15. VLT spectra of GRB 021211 revisited
  16. GRB021219: a long GRB localized by INTEGRAL
  17. GRB021211: APO optical observations
  18. IPN detection of continued activity from SGR1806-20
  19. IPN triangulation of GRB021215 (large error box)
  20. IPN triangulation of GRB021214 (annulus)
  21. XRF 020903 : HST observations
  22. GRB 021201: Optical Observations
  23. GRB 021211, optical observations
  24. GRB 021211: CTIO observations
  25. GRB021211: Measurement of Early Time Afterglow
  26. VLT spectrum of GRB 021211
  27. IPN triangulation of GRB021211B (two large error boxes)
  28. GRB 021211: early break in light curve
  29. GRB021211, BVRI field photometry
  30. GRB021211: Optical observations in CrAO
  31. GRB 021211, IR observations
  32. GRB 021211, optical observations
  33. GRB 021211: Optical Observations
  34. GRB021211: Kiso Observations
  35. GRB021204: Kiso Observations
  36. GRB 021201, optical observations
  37. GRB 021211: Radio Observations
  38. GRB021211: Optical observations
  39. GRB 021201 (short/hard), NOT observations
  40. SUB-MM SEARCH FOR GRB 021211
  41. Chandra observation of the IPN error box of GRB021201 (short/hard)
  42. GRB 021211 Milagro GeV/TeV Observations
  43. GRB 021211, R- and I-band observations
  44. GRB021211 - Upper limits from recent and historical observations
  45. GRB021211, OT at 108 s
  46. GRB021211 (HETE2493), OT at 143 sec
  47. GRB 021204: I-band Observations
  48. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  49. HETE 2493: Optical observations
  50. HETE 2493: Optical observations
  51. HETE 2493: Optical candidate
  52. GRB 021204: Optical Observations at RIKEN
  53. GRB 021125: Radio Observations
  54. IPN triangulation of GRB021206 (small error box)
  55. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  56. IPN detection of renewed activity from SGR1806-20
  57. IPN triangulation of GRB021205 (large error box)
  58. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  59. GRB021201, BVRcIc field photometry
  60. GRB 021201, Radio Observations
  61. GRB 021201: Optical Observations
  62. GRB 021201: BOOTES simultaneous optical observations
  63. IPN triangulation of GRB021201 (short/hard burst, small error box)
  64. Radio Catalog of GRB Afterglows
  65. GRB021004, late time optical observations
  66. GRB021004 Chandra Observation
  67. IPN detection of continued SGR1900+14 activity
  68. GRB021125 refined position
  69. IPN triangulation of GRB021115 (annulus)
  70. IPN triangulation of GRB021125B (two large error boxes)
  71. IPN triangulation of GRB021119 (large error box)
  72. IPN triangulation of GRB021125B (annulus)
  73. Improved IPN error box for GRB021125
  74. IPN BURST POSITION
  75. IPN triangulation of GRB021125 (INTEGRAL BURST)
  76. GRB021125 : A long GRB localized by INTEGRAL
  77. IPN confirmation of the reactivation of SGR1900+14
  78. IPN detection of possible reactivation of SGR1900+14
  79. GRB021113, SPI ACS observation
  80. IPN triangulation of GRB021119 (annulus)
  81. GRB 021112: Afterglow or Variable Star?
  82. GRB021113: optical observations at Bisei
  83. GRB 021113: Evidence for a Dark Optical Afterglow
  84. GRB 021112, Radio Observations
  85. GRB021112, BVRI field photometry
  86. GRB 021112: Variable Source in R-band search
  87. GRB021112: Optical Observations
  88. GRB021113: Kiso Observations
  89. IPN triangulation of GRB021109 (portion of annulus)
  90. IPN triangulation of GRB021113 (=H2449; annulus)
  91. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  92. GRB 021113: Optical observations
  93. GRB 021112: RAPTOR Observations
  94. GRB 021113: Optical Observations
  95. GRB 021113: Optical Observations
  96. GRB021113 (=H2449): A Long GRB Localized by HETE
  97. GRB 021112: Optical Observations
  98. GRB 021112: R-band search
  99. IPN triangulation of GRB021108 (large error box)
  100. GRB021112 (=H2448): A Long GRB Localized by HETE

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