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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, optical observations
  2. GRB 021211: CTIO observations
  3. GRB021211: Measurement of Early Time Afterglow
  4. VLT spectrum of GRB 021211
  5. IPN triangulation of GRB021211B (two large error boxes)
  6. GRB 021211: early break in light curve
  7. GRB021211, BVRI field photometry
  8. GRB021211: Optical observations in CrAO
  9. GRB 021211, IR observations
  10. GRB 021211, optical observations
  11. GRB 021211: Optical Observations
  12. GRB021211: Kiso Observations
  13. GRB021204: Kiso Observations
  14. GRB 021201, optical observations
  15. GRB 021211: Radio Observations
  16. GRB021211: Optical observations
  17. GRB 021201 (short/hard), NOT observations
  18. SUB-MM SEARCH FOR GRB 021211
  19. Chandra observation of the IPN error box of GRB021201 (short/hard)
  20. GRB 021211 Milagro GeV/TeV Observations
  21. GRB 021211, R- and I-band observations
  22. GRB021211 - Upper limits from recent and historical observations
  23. GRB021211, OT at 108 s
  24. GRB021211 (HETE2493), OT at 143 sec
  25. GRB 021204: I-band Observations
  26. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  27. HETE 2493: Optical observations
  28. HETE 2493: Optical observations
  29. HETE 2493: Optical candidate
  30. GRB 021204: Optical Observations at RIKEN
  31. GRB 021125: Radio Observations
  32. IPN triangulation of GRB021206 (small error box)
  33. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  34. IPN detection of renewed activity from SGR1806-20
  35. IPN triangulation of GRB021205 (large error box)
  36. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  37. GRB021201, BVRcIc field photometry
  38. GRB 021201, Radio Observations
  39. GRB 021201: Optical Observations
  40. GRB 021201: BOOTES simultaneous optical observations
  41. IPN triangulation of GRB021201 (short/hard burst, small error box)
  42. Radio Catalog of GRB Afterglows
  43. GRB021004, late time optical observations
  44. GRB021004 Chandra Observation
  45. IPN detection of continued SGR1900+14 activity
  46. GRB021125 refined position
  47. IPN triangulation of GRB021115 (annulus)
  48. IPN triangulation of GRB021125B (two large error boxes)
  49. IPN triangulation of GRB021119 (large error box)
  50. IPN triangulation of GRB021125B (annulus)
  51. Improved IPN error box for GRB021125
  52. IPN BURST POSITION
  53. IPN triangulation of GRB021125 (INTEGRAL BURST)
  54. GRB021125 : A long GRB localized by INTEGRAL
  55. IPN confirmation of the reactivation of SGR1900+14
  56. IPN detection of possible reactivation of SGR1900+14
  57. GRB021113, SPI ACS observation
  58. IPN triangulation of GRB021119 (annulus)
  59. GRB 021112: Afterglow or Variable Star?
  60. GRB021113: optical observations at Bisei
  61. GRB 021113: Evidence for a Dark Optical Afterglow
  62. GRB 021112, Radio Observations
  63. GRB021112, BVRI field photometry
  64. GRB 021112: Variable Source in R-band search
  65. GRB021112: Optical Observations
  66. GRB021113: Kiso Observations
  67. IPN triangulation of GRB021109 (portion of annulus)
  68. IPN triangulation of GRB021113 (=H2449; annulus)
  69. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  70. GRB 021113: Optical observations
  71. GRB 021112: RAPTOR Observations
  72. GRB 021113: Optical Observations
  73. GRB 021113: Optical Observations
  74. GRB021113 (=H2449): A Long GRB Localized by HETE
  75. GRB 021112: Optical Observations
  76. GRB 021112: R-band search
  77. IPN triangulation of GRB021108 (large error box)
  78. GRB021112 (=H2448): A Long GRB Localized by HETE
  79. GRB 021016: Optical Observations
  80. IPN triangulation of GRB021109 (annulus)
  81. IPN triangulation of GRB021108 (annulus)
  82. GRB021004: Near infrared spectroscopy
  83. GRB021104: Optical Observations
  84. IPN triangulation of GRB021104 (annulus)
  85. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  86. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  87. SGR1900+14 activity, November 2-4, 2002
  88. Spectropolarimetry of GRB021004
  89. GRB021104: Optical observations
  90. GRB021104: optical observations
  91. GRB021104: Candidate present in DSS
  92. GRB021104: possible optical afterglow
  93. IPN triangulation of GRB021102 (annulus)
  94. Detection of activity from SGR 1900+14 with the RXTE/PCA
  95. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  96. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  97. IPN triangulation of GRB021025 (portion of annulus)
  98. IPN triangulation of GRB021027 (single large error box)
  99. GRB021004, late-time optical observations
  100. IPN triangulation of GRB021027 (two large error boxes)

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