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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. Possible GRB 20030109 seen by SPI ACS
  2. IPN triangulation of GRB030102A - correction to peak flux
  3. IPN triangulation of GRB030102B (portion of annulus)
  4. IPN triangulation of GRB030102A (large error box)
  5. Coronas-F -Wind triangulation of GRB030102
  6. Possible GRB20030107 seen by SPI-ACS
  7. Possible GRB 20030105 seen by SPI ACS
  8. IPN triangulation of GRB030102 (annulus)
  9. GRB on 20030102 seen by SPI-ACS
  10. VLT spectroscopy of the probable host of GRB 021211
  11. GRB on 20030101 seen by SPI-ACS
  12. IPN triangulation of GRB030101 (two large error boxes)
  13. GRB021226
  14. GRB 021211: Probable Host and Underlying Supernova
  15. GRB 021226 registration by Helicon/Coronas-F
  16. Probable GRB in INTEGRAL SPI-ACS
  17. IPN triangulation of GRB021223 (two large error boxes)
  18. GRB021211, radio observations
  19. GRB 021112: Evidence for Another Dark Optical Afterglow
  20. GRB 021219: OSN optical observations
  21. GRB021219: Radio Observations
  22. GRB021219, optical observations
  23. IPN triangulation of GRB021219 - CORRECTION
  24. IPN triangulation of GRB021219
  25. GRB021219, optical observation by MASTER
  26. GRB021219: Correction to GCN 1766
  27. GRB021219 refined position with INTEGRAL
  28. VLT spectra of GRB 021211 revisited
  29. GRB021219: a long GRB localized by INTEGRAL
  30. GRB021211: APO optical observations
  31. IPN detection of continued activity from SGR1806-20
  32. IPN triangulation of GRB021215 (large error box)
  33. IPN triangulation of GRB021214 (annulus)
  34. XRF 020903 : HST observations
  35. GRB 021201: Optical Observations
  36. GRB 021211, optical observations
  37. GRB 021211: CTIO observations
  38. GRB021211: Measurement of Early Time Afterglow
  39. VLT spectrum of GRB 021211
  40. IPN triangulation of GRB021211B (two large error boxes)
  41. GRB 021211: early break in light curve
  42. GRB021211, BVRI field photometry
  43. GRB021211: Optical observations in CrAO
  44. GRB 021211, IR observations
  45. GRB 021211, optical observations
  46. GRB 021211: Optical Observations
  47. GRB021211: Kiso Observations
  48. GRB021204: Kiso Observations
  49. GRB 021201, optical observations
  50. GRB 021211: Radio Observations
  51. GRB021211: Optical observations
  52. GRB 021201 (short/hard), NOT observations
  53. SUB-MM SEARCH FOR GRB 021211
  54. Chandra observation of the IPN error box of GRB021201 (short/hard)
  55. GRB 021211 Milagro GeV/TeV Observations
  56. GRB 021211, R- and I-band observations
  57. GRB021211 - Upper limits from recent and historical observations
  58. GRB021211, OT at 108 s
  59. GRB021211 (HETE2493), OT at 143 sec
  60. GRB 021204: I-band Observations
  61. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  62. HETE 2493: Optical observations
  63. HETE 2493: Optical observations
  64. HETE 2493: Optical candidate
  65. GRB 021204: Optical Observations at RIKEN
  66. GRB 021125: Radio Observations
  67. IPN triangulation of GRB021206 (small error box)
  68. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  69. IPN detection of renewed activity from SGR1806-20
  70. IPN triangulation of GRB021205 (large error box)
  71. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  72. GRB021201, BVRcIc field photometry
  73. GRB 021201, Radio Observations
  74. GRB 021201: Optical Observations
  75. GRB 021201: BOOTES simultaneous optical observations
  76. IPN triangulation of GRB021201 (short/hard burst, small error box)
  77. Radio Catalog of GRB Afterglows
  78. GRB021004, late time optical observations
  79. GRB021004 Chandra Observation
  80. IPN detection of continued SGR1900+14 activity
  81. GRB021125 refined position
  82. IPN triangulation of GRB021115 (annulus)
  83. IPN triangulation of GRB021125B (two large error boxes)
  84. IPN triangulation of GRB021119 (large error box)
  85. IPN triangulation of GRB021125B (annulus)
  86. Improved IPN error box for GRB021125
  87. IPN BURST POSITION
  88. IPN triangulation of GRB021125 (INTEGRAL BURST)
  89. GRB021125 : A long GRB localized by INTEGRAL
  90. IPN confirmation of the reactivation of SGR1900+14
  91. IPN detection of possible reactivation of SGR1900+14
  92. GRB021113, SPI ACS observation
  93. IPN triangulation of GRB021119 (annulus)
  94. GRB 021112: Afterglow or Variable Star?
  95. GRB021113: optical observations at Bisei
  96. GRB 021113: Evidence for a Dark Optical Afterglow
  97. GRB 021112, Radio Observations
  98. GRB021112, BVRI field photometry
  99. GRB 021112: Variable Source in R-band search
  100. GRB021112: Optical Observations

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