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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. GRB021211, radio observations
  2. GRB 021112: Evidence for Another Dark Optical Afterglow
  3. GRB 021219: OSN optical observations
  4. GRB021219: Radio Observations
  5. GRB021219, optical observations
  6. IPN triangulation of GRB021219 - CORRECTION
  7. IPN triangulation of GRB021219
  8. GRB021219, optical observation by MASTER
  9. GRB021219: Correction to GCN 1766
  10. GRB021219 refined position with INTEGRAL
  11. VLT spectra of GRB 021211 revisited
  12. GRB021219: a long GRB localized by INTEGRAL
  13. GRB021211: APO optical observations
  14. IPN detection of continued activity from SGR1806-20
  15. IPN triangulation of GRB021215 (large error box)
  16. IPN triangulation of GRB021214 (annulus)
  17. XRF 020903 : HST observations
  18. GRB 021201: Optical Observations
  19. GRB 021211, optical observations
  20. GRB 021211: CTIO observations
  21. GRB021211: Measurement of Early Time Afterglow
  22. VLT spectrum of GRB 021211
  23. IPN triangulation of GRB021211B (two large error boxes)
  24. GRB 021211: early break in light curve
  25. GRB021211, BVRI field photometry
  26. GRB021211: Optical observations in CrAO
  27. GRB 021211, IR observations
  28. GRB 021211, optical observations
  29. GRB 021211: Optical Observations
  30. GRB021211: Kiso Observations
  31. GRB021204: Kiso Observations
  32. GRB 021201, optical observations
  33. GRB 021211: Radio Observations
  34. GRB021211: Optical observations
  35. GRB 021201 (short/hard), NOT observations
  36. SUB-MM SEARCH FOR GRB 021211
  37. Chandra observation of the IPN error box of GRB021201 (short/hard)
  38. GRB 021211 Milagro GeV/TeV Observations
  39. GRB 021211, R- and I-band observations
  40. GRB021211 - Upper limits from recent and historical observations
  41. GRB021211, OT at 108 s
  42. GRB021211 (HETE2493), OT at 143 sec
  43. GRB 021204: I-band Observations
  44. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  45. HETE 2493: Optical observations
  46. HETE 2493: Optical observations
  47. HETE 2493: Optical candidate
  48. GRB 021204: Optical Observations at RIKEN
  49. GRB 021125: Radio Observations
  50. IPN triangulation of GRB021206 (small error box)
  51. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  52. IPN detection of renewed activity from SGR1806-20
  53. IPN triangulation of GRB021205 (large error box)
  54. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  55. GRB021201, BVRcIc field photometry
  56. GRB 021201, Radio Observations
  57. GRB 021201: Optical Observations
  58. GRB 021201: BOOTES simultaneous optical observations
  59. IPN triangulation of GRB021201 (short/hard burst, small error box)
  60. Radio Catalog of GRB Afterglows
  61. GRB021004, late time optical observations
  62. GRB021004 Chandra Observation
  63. IPN detection of continued SGR1900+14 activity
  64. GRB021125 refined position
  65. IPN triangulation of GRB021115 (annulus)
  66. IPN triangulation of GRB021125B (two large error boxes)
  67. IPN triangulation of GRB021119 (large error box)
  68. IPN triangulation of GRB021125B (annulus)
  69. Improved IPN error box for GRB021125
  70. IPN BURST POSITION
  71. IPN triangulation of GRB021125 (INTEGRAL BURST)
  72. GRB021125 : A long GRB localized by INTEGRAL
  73. IPN confirmation of the reactivation of SGR1900+14
  74. IPN detection of possible reactivation of SGR1900+14
  75. GRB021113, SPI ACS observation
  76. IPN triangulation of GRB021119 (annulus)
  77. GRB 021112: Afterglow or Variable Star?
  78. GRB021113: optical observations at Bisei
  79. GRB 021113: Evidence for a Dark Optical Afterglow
  80. GRB 021112, Radio Observations
  81. GRB021112, BVRI field photometry
  82. GRB 021112: Variable Source in R-band search
  83. GRB021112: Optical Observations
  84. GRB021113: Kiso Observations
  85. IPN triangulation of GRB021109 (portion of annulus)
  86. IPN triangulation of GRB021113 (=H2449; annulus)
  87. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  88. GRB 021113: Optical observations
  89. GRB 021112: RAPTOR Observations
  90. GRB 021113: Optical Observations
  91. GRB 021113: Optical Observations
  92. GRB021113 (=H2449): A Long GRB Localized by HETE
  93. GRB 021112: Optical Observations
  94. GRB 021112: R-band search
  95. IPN triangulation of GRB021108 (large error box)
  96. GRB021112 (=H2448): A Long GRB Localized by HETE
  97. GRB 021016: Optical Observations
  98. IPN triangulation of GRB021109 (annulus)
  99. IPN triangulation of GRB021108 (annulus)
  100. GRB021004: Near infrared spectroscopy

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