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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').
  1. GRB 021211, IR observations
  2. GRB 021211, optical observations
  3. GRB 021211: Optical Observations
  4. GRB021211: Kiso Observations
  5. GRB021204: Kiso Observations
  6. GRB 021201, optical observations
  7. GRB 021211: Radio Observations
  8. GRB021211: Optical observations
  9. GRB 021201 (short/hard), NOT observations
  10. SUB-MM SEARCH FOR GRB 021211
  11. Chandra observation of the IPN error box of GRB021201 (short/hard)
  12. GRB 021211 Milagro GeV/TeV Observations
  13. GRB 021211, R- and I-band observations
  14. GRB021211 - Upper limits from recent and historical observations
  15. GRB021211, OT at 108 s
  16. GRB021211 (HETE2493), OT at 143 sec
  17. GRB 021204: I-band Observations
  18. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  19. HETE 2493: Optical observations
  20. HETE 2493: Optical observations
  21. HETE 2493: Optical candidate
  22. GRB 021204: Optical Observations at RIKEN
  23. GRB 021125: Radio Observations
  24. IPN triangulation of GRB021206 (small error box)
  25. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  26. IPN detection of renewed activity from SGR1806-20
  27. IPN triangulation of GRB021205 (large error box)
  28. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  29. GRB021201, BVRcIc field photometry
  30. GRB 021201, Radio Observations
  31. GRB 021201: Optical Observations
  32. GRB 021201: BOOTES simultaneous optical observations
  33. IPN triangulation of GRB021201 (short/hard burst, small error box)
  34. Radio Catalog of GRB Afterglows
  35. GRB021004, late time optical observations
  36. GRB021004 Chandra Observation
  37. IPN detection of continued SGR1900+14 activity
  38. GRB021125 refined position
  39. IPN triangulation of GRB021115 (annulus)
  40. IPN triangulation of GRB021125B (two large error boxes)
  41. IPN triangulation of GRB021119 (large error box)
  42. IPN triangulation of GRB021125B (annulus)
  43. Improved IPN error box for GRB021125
  44. IPN BURST POSITION
  45. IPN triangulation of GRB021125 (INTEGRAL BURST)
  46. GRB021125 : A long GRB localized by INTEGRAL
  47. IPN confirmation of the reactivation of SGR1900+14
  48. IPN detection of possible reactivation of SGR1900+14
  49. GRB021113, SPI ACS observation
  50. IPN triangulation of GRB021119 (annulus)
  51. GRB 021112: Afterglow or Variable Star?
  52. GRB021113: optical observations at Bisei
  53. GRB 021113: Evidence for a Dark Optical Afterglow
  54. GRB 021112, Radio Observations
  55. GRB021112, BVRI field photometry
  56. GRB 021112: Variable Source in R-band search
  57. GRB021112: Optical Observations
  58. GRB021113: Kiso Observations
  59. IPN triangulation of GRB021109 (portion of annulus)
  60. IPN triangulation of GRB021113 (=H2449; annulus)
  61. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  62. GRB 021113: Optical observations
  63. GRB 021112: RAPTOR Observations
  64. GRB 021113: Optical Observations
  65. GRB 021113: Optical Observations
  66. GRB021113 (=H2449): A Long GRB Localized by HETE
  67. GRB 021112: Optical Observations
  68. GRB 021112: R-band search
  69. IPN triangulation of GRB021108 (large error box)
  70. GRB021112 (=H2448): A Long GRB Localized by HETE
  71. GRB 021016: Optical Observations
  72. IPN triangulation of GRB021109 (annulus)
  73. IPN triangulation of GRB021108 (annulus)
  74. GRB021004: Near infrared spectroscopy
  75. GRB021104: Optical Observations
  76. IPN triangulation of GRB021104 (annulus)
  77. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  78. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  79. SGR1900+14 activity, November 2-4, 2002
  80. Spectropolarimetry of GRB021004
  81. GRB021104: Optical observations
  82. GRB021104: optical observations
  83. GRB021104: Candidate present in DSS
  84. GRB021104: possible optical afterglow
  85. IPN triangulation of GRB021102 (annulus)
  86. Detection of activity from SGR 1900+14 with the RXTE/PCA
  87. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  88. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  89. IPN triangulation of GRB021025 (portion of annulus)
  90. IPN triangulation of GRB021027 (single large error box)
  91. GRB021004, late-time optical observations
  92. IPN triangulation of GRB021027 (two large error boxes)
  93. GRB 021023: Infrared Imaging
  94. IPN triangulation of GRB021027 (annulus)
  95. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  96. IPN triangulation of GRB021025 (annulus)
  97. IPN triangulation of SGR1900+14, October 22 2002
  98. GRB 021004: optical observations
  99. IPN triangulation of GRB021023 (small error boc)
  100. GRB021004: Optical Observations

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