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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. IPN triangulation of GRB021219 - CORRECTION
  2. IPN triangulation of GRB021219
  3. GRB021219, optical observation by MASTER
  4. GRB021219: Correction to GCN 1766
  5. GRB021219 refined position with INTEGRAL
  6. VLT spectra of GRB 021211 revisited
  7. GRB021219: a long GRB localized by INTEGRAL
  8. GRB021211: APO optical observations
  9. IPN detection of continued activity from SGR1806-20
  10. IPN triangulation of GRB021215 (large error box)
  11. IPN triangulation of GRB021214 (annulus)
  12. XRF 020903 : HST observations
  13. GRB 021201: Optical Observations
  14. GRB 021211, optical observations
  15. GRB 021211: CTIO observations
  16. GRB021211: Measurement of Early Time Afterglow
  17. VLT spectrum of GRB 021211
  18. IPN triangulation of GRB021211B (two large error boxes)
  19. GRB 021211: early break in light curve
  20. GRB021211, BVRI field photometry
  21. GRB021211: Optical observations in CrAO
  22. GRB 021211, IR observations
  23. GRB 021211, optical observations
  24. GRB 021211: Optical Observations
  25. GRB021211: Kiso Observations
  26. GRB021204: Kiso Observations
  27. GRB 021201, optical observations
  28. GRB 021211: Radio Observations
  29. GRB021211: Optical observations
  30. GRB 021201 (short/hard), NOT observations
  31. SUB-MM SEARCH FOR GRB 021211
  32. Chandra observation of the IPN error box of GRB021201 (short/hard)
  33. GRB 021211 Milagro GeV/TeV Observations
  34. GRB 021211, R- and I-band observations
  35. GRB021211 - Upper limits from recent and historical observations
  36. GRB021211, OT at 108 s
  37. GRB021211 (HETE2493), OT at 143 sec
  38. GRB 021204: I-band Observations
  39. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  40. HETE 2493: Optical observations
  41. HETE 2493: Optical observations
  42. HETE 2493: Optical candidate
  43. GRB 021204: Optical Observations at RIKEN
  44. GRB 021125: Radio Observations
  45. IPN triangulation of GRB021206 (small error box)
  46. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  47. IPN detection of renewed activity from SGR1806-20
  48. IPN triangulation of GRB021205 (large error box)
  49. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  50. GRB021201, BVRcIc field photometry
  51. GRB 021201, Radio Observations
  52. GRB 021201: Optical Observations
  53. GRB 021201: BOOTES simultaneous optical observations
  54. IPN triangulation of GRB021201 (short/hard burst, small error box)
  55. Radio Catalog of GRB Afterglows
  56. GRB021004, late time optical observations
  57. GRB021004 Chandra Observation
  58. IPN detection of continued SGR1900+14 activity
  59. GRB021125 refined position
  60. IPN triangulation of GRB021115 (annulus)
  61. IPN triangulation of GRB021125B (two large error boxes)
  62. IPN triangulation of GRB021119 (large error box)
  63. IPN triangulation of GRB021125B (annulus)
  64. Improved IPN error box for GRB021125
  65. IPN BURST POSITION
  66. IPN triangulation of GRB021125 (INTEGRAL BURST)
  67. GRB021125 : A long GRB localized by INTEGRAL
  68. IPN confirmation of the reactivation of SGR1900+14
  69. IPN detection of possible reactivation of SGR1900+14
  70. GRB021113, SPI ACS observation
  71. IPN triangulation of GRB021119 (annulus)
  72. GRB 021112: Afterglow or Variable Star?
  73. GRB021113: optical observations at Bisei
  74. GRB 021113: Evidence for a Dark Optical Afterglow
  75. GRB 021112, Radio Observations
  76. GRB021112, BVRI field photometry
  77. GRB 021112: Variable Source in R-band search
  78. GRB021112: Optical Observations
  79. GRB021113: Kiso Observations
  80. IPN triangulation of GRB021109 (portion of annulus)
  81. IPN triangulation of GRB021113 (=H2449; annulus)
  82. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  83. GRB 021113: Optical observations
  84. GRB 021112: RAPTOR Observations
  85. GRB 021113: Optical Observations
  86. GRB 021113: Optical Observations
  87. GRB021113 (=H2449): A Long GRB Localized by HETE
  88. GRB 021112: Optical Observations
  89. GRB 021112: R-band search
  90. IPN triangulation of GRB021108 (large error box)
  91. GRB021112 (=H2448): A Long GRB Localized by HETE
  92. GRB 021016: Optical Observations
  93. IPN triangulation of GRB021109 (annulus)
  94. IPN triangulation of GRB021108 (annulus)
  95. GRB021004: Near infrared spectroscopy
  96. GRB021104: Optical Observations
  97. IPN triangulation of GRB021104 (annulus)
  98. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  99. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  100. SGR1900+14 activity, November 2-4, 2002

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