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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 on 20030102 seen by SPI-ACS
  2. VLT spectroscopy of the probable host of GRB 021211
  3. GRB on 20030101 seen by SPI-ACS
  4. IPN triangulation of GRB030101 (two large error boxes)
  5. GRB021226
  6. GRB 021211: Probable Host and Underlying Supernova
  7. GRB 021226 registration by Helicon/Coronas-F
  8. Probable GRB in INTEGRAL SPI-ACS
  9. IPN triangulation of GRB021223 (two large error boxes)
  10. GRB021211, radio observations
  11. GRB 021112: Evidence for Another Dark Optical Afterglow
  12. GRB 021219: OSN optical observations
  13. GRB021219: Radio Observations
  14. GRB021219, optical observations
  15. IPN triangulation of GRB021219 - CORRECTION
  16. IPN triangulation of GRB021219
  17. GRB021219, optical observation by MASTER
  18. GRB021219: Correction to GCN 1766
  19. GRB021219 refined position with INTEGRAL
  20. VLT spectra of GRB 021211 revisited
  21. GRB021219: a long GRB localized by INTEGRAL
  22. GRB021211: APO optical observations
  23. IPN detection of continued activity from SGR1806-20
  24. IPN triangulation of GRB021215 (large error box)
  25. IPN triangulation of GRB021214 (annulus)
  26. XRF 020903 : HST observations
  27. GRB 021201: Optical Observations
  28. GRB 021211, optical observations
  29. GRB 021211: CTIO observations
  30. GRB021211: Measurement of Early Time Afterglow
  31. VLT spectrum of GRB 021211
  32. IPN triangulation of GRB021211B (two large error boxes)
  33. GRB 021211: early break in light curve
  34. GRB021211, BVRI field photometry
  35. GRB021211: Optical observations in CrAO
  36. GRB 021211, IR observations
  37. GRB 021211, optical observations
  38. GRB 021211: Optical Observations
  39. GRB021211: Kiso Observations
  40. GRB021204: Kiso Observations
  41. GRB 021201, optical observations
  42. GRB 021211: Radio Observations
  43. GRB021211: Optical observations
  44. GRB 021201 (short/hard), NOT observations
  45. SUB-MM SEARCH FOR GRB 021211
  46. Chandra observation of the IPN error box of GRB021201 (short/hard)
  47. GRB 021211 Milagro GeV/TeV Observations
  48. GRB 021211, R- and I-band observations
  49. GRB021211 - Upper limits from recent and historical observations
  50. GRB021211, OT at 108 s
  51. GRB021211 (HETE2493), OT at 143 sec
  52. GRB 021204: I-band Observations
  53. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  54. HETE 2493: Optical observations
  55. HETE 2493: Optical observations
  56. HETE 2493: Optical candidate
  57. GRB 021204: Optical Observations at RIKEN
  58. GRB 021125: Radio Observations
  59. IPN triangulation of GRB021206 (small error box)
  60. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  61. IPN detection of renewed activity from SGR1806-20
  62. IPN triangulation of GRB021205 (large error box)
  63. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  64. GRB021201, BVRcIc field photometry
  65. GRB 021201, Radio Observations
  66. GRB 021201: Optical Observations
  67. GRB 021201: BOOTES simultaneous optical observations
  68. IPN triangulation of GRB021201 (short/hard burst, small error box)
  69. Radio Catalog of GRB Afterglows
  70. GRB021004, late time optical observations
  71. GRB021004 Chandra Observation
  72. IPN detection of continued SGR1900+14 activity
  73. GRB021125 refined position
  74. IPN triangulation of GRB021115 (annulus)
  75. IPN triangulation of GRB021125B (two large error boxes)
  76. IPN triangulation of GRB021119 (large error box)
  77. IPN triangulation of GRB021125B (annulus)
  78. Improved IPN error box for GRB021125
  79. IPN BURST POSITION
  80. IPN triangulation of GRB021125 (INTEGRAL BURST)
  81. GRB021125 : A long GRB localized by INTEGRAL
  82. IPN confirmation of the reactivation of SGR1900+14
  83. IPN detection of possible reactivation of SGR1900+14
  84. GRB021113, SPI ACS observation
  85. IPN triangulation of GRB021119 (annulus)
  86. GRB 021112: Afterglow or Variable Star?
  87. GRB021113: optical observations at Bisei
  88. GRB 021113: Evidence for a Dark Optical Afterglow
  89. GRB 021112, Radio Observations
  90. GRB021112, BVRI field photometry
  91. GRB 021112: Variable Source in R-band search
  92. GRB021112: Optical Observations
  93. GRB021113: Kiso Observations
  94. IPN triangulation of GRB021109 (portion of annulus)
  95. IPN triangulation of GRB021113 (=H2449; annulus)
  96. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  97. GRB 021113: Optical observations
  98. GRB 021112: RAPTOR Observations
  99. GRB 021113: Optical Observations
  100. GRB 021113: Optical Observations

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