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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: Radio Observations
  2. GRB021211: Optical observations
  3. GRB 021201 (short/hard), NOT observations
  4. SUB-MM SEARCH FOR GRB 021211
  5. Chandra observation of the IPN error box of GRB021201 (short/hard)
  6. GRB 021211 Milagro GeV/TeV Observations
  7. GRB 021211, R- and I-band observations
  8. GRB021211 - Upper limits from recent and historical observations
  9. GRB021211, OT at 108 s
  10. GRB021211 (HETE2493), OT at 143 sec
  11. GRB 021204: I-band Observations
  12. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  13. HETE 2493: Optical observations
  14. HETE 2493: Optical observations
  15. HETE 2493: Optical candidate
  16. GRB 021204: Optical Observations at RIKEN
  17. GRB 021125: Radio Observations
  18. IPN triangulation of GRB021206 (small error box)
  19. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  20. IPN detection of renewed activity from SGR1806-20
  21. IPN triangulation of GRB021205 (large error box)
  22. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  23. GRB021201, BVRcIc field photometry
  24. GRB 021201, Radio Observations
  25. GRB 021201: Optical Observations
  26. GRB 021201: BOOTES simultaneous optical observations
  27. IPN triangulation of GRB021201 (short/hard burst, small error box)
  28. Radio Catalog of GRB Afterglows
  29. GRB021004, late time optical observations
  30. GRB021004 Chandra Observation
  31. IPN detection of continued SGR1900+14 activity
  32. GRB021125 refined position
  33. IPN triangulation of GRB021115 (annulus)
  34. IPN triangulation of GRB021125B (two large error boxes)
  35. IPN triangulation of GRB021119 (large error box)
  36. IPN triangulation of GRB021125B (annulus)
  37. Improved IPN error box for GRB021125
  38. IPN BURST POSITION
  39. IPN triangulation of GRB021125 (INTEGRAL BURST)
  40. GRB021125 : A long GRB localized by INTEGRAL
  41. IPN confirmation of the reactivation of SGR1900+14
  42. IPN detection of possible reactivation of SGR1900+14
  43. GRB021113, SPI ACS observation
  44. IPN triangulation of GRB021119 (annulus)
  45. GRB 021112: Afterglow or Variable Star?
  46. GRB021113: optical observations at Bisei
  47. GRB 021113: Evidence for a Dark Optical Afterglow
  48. GRB 021112, Radio Observations
  49. GRB021112, BVRI field photometry
  50. GRB 021112: Variable Source in R-band search
  51. GRB021112: Optical Observations
  52. GRB021113: Kiso Observations
  53. IPN triangulation of GRB021109 (portion of annulus)
  54. IPN triangulation of GRB021113 (=H2449; annulus)
  55. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  56. GRB 021113: Optical observations
  57. GRB 021112: RAPTOR Observations
  58. GRB 021113: Optical Observations
  59. GRB 021113: Optical Observations
  60. GRB021113 (=H2449): A Long GRB Localized by HETE
  61. GRB 021112: Optical Observations
  62. GRB 021112: R-band search
  63. IPN triangulation of GRB021108 (large error box)
  64. GRB021112 (=H2448): A Long GRB Localized by HETE
  65. GRB 021016: Optical Observations
  66. IPN triangulation of GRB021109 (annulus)
  67. IPN triangulation of GRB021108 (annulus)
  68. GRB021004: Near infrared spectroscopy
  69. GRB021104: Optical Observations
  70. IPN triangulation of GRB021104 (annulus)
  71. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  72. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  73. SGR1900+14 activity, November 2-4, 2002
  74. Spectropolarimetry of GRB021004
  75. GRB021104: Optical observations
  76. GRB021104: optical observations
  77. GRB021104: Candidate present in DSS
  78. GRB021104: possible optical afterglow
  79. IPN triangulation of GRB021102 (annulus)
  80. Detection of activity from SGR 1900+14 with the RXTE/PCA
  81. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  82. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  83. IPN triangulation of GRB021025 (portion of annulus)
  84. IPN triangulation of GRB021027 (single large error box)
  85. GRB021004, late-time optical observations
  86. IPN triangulation of GRB021027 (two large error boxes)
  87. GRB 021023: Infrared Imaging
  88. IPN triangulation of GRB021027 (annulus)
  89. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  90. IPN triangulation of GRB021025 (annulus)
  91. IPN triangulation of SGR1900+14, October 22 2002
  92. GRB 021004: optical observations
  93. IPN triangulation of GRB021023 (small error boc)
  94. GRB021004: Optical Observations
  95. GRB 020813; likely host galaxy.
  96. IPN triangulation of GRB021020 (smaller error box)
  97. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  98. IPN triangulation of GRB021020
  99. GRB 021008, radio observations
  100. GRB 021016, optical observations

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