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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"

37938 results found.

  1. GRB 021211: VLT spectrum
  2. GRB 030115: APO Optical Observations
  3. GRB 030115, no optical candidate
  4. GRB 030115, optical observations
  5. GRB 030115, optical candidate
  6. Possible GRB030113 seen by SPI ACS
  7. Probable GRB030112B seen by SPI ACS
  8. Probable GRB030112 seen by SPI ACS
  9. Possible GRB030111 seen by SPI ACS
  10. Possible GRB030110b seen by SPI ACS
  11. Possible GRB 030110 seen by SPI ACS
  12. IPN triangulation of GRB030109 (annulus)
  13. IPN triangulation of GRB030105 (large error box)
  14. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  15. Possible GRB 20030109 seen by SPI ACS
  16. IPN triangulation of GRB030102B (portion of annulus)
  17. IPN triangulation of GRB030102A (large error box)
  18. Possible GRB20030107 seen by SPI-ACS
  19. Possible GRB 20030105 seen by SPI ACS
  20. IPN triangulation of GRB030102 (annulus)
  21. GRB on 20030102 seen by SPI-ACS
  22. VLT spectroscopy of the probable host of GRB 021211
  23. GRB on 20030101 seen by SPI-ACS
  24. IPN triangulation of GRB030101 (two large error boxes)
  25. GRB021226
  26. GRB 021211: Probable Host and Underlying Supernova
  27. GRB 021226 registration by Helicon/Coronas-F
  28. Probable GRB in INTEGRAL SPI-ACS
  29. IPN triangulation of GRB021223 (two large error boxes)
  30. GRB021211, radio observations
  31. GRB 021112: Evidence for Another Dark Optical Afterglow
  32. GRB 021219: OSN optical observations
  33. GRB021219: Radio Observations
  34. IPN triangulation of GRB021219 - CORRECTION
  35. IPN triangulation of GRB021219
  36. GRB021219, optical observation by MASTER
  37. GRB021219: Correction to GCN 1766
  38. VLT spectra of GRB 021211 revisited
  39. GRB021219: a long GRB localized by INTEGRAL
  40. IPN detection of continued activity from SGR1806-20
  41. IPN triangulation of GRB021215 (large error box)
  42. IPN triangulation of GRB021214 (annulus)
  43. XRF 020903 : HST observations
  44. GRB 021201: Optical Observations
  45. GRB 021211, optical observations
  46. GRB 021211: CTIO observations
  47. GRB021211: Measurement of Early Time Afterglow
  48. VLT spectrum of GRB 021211
  49. IPN triangulation of GRB021211B (two large error boxes)
  50. GRB 021211: early break in light curve
  51. GRB021211, BVRI field photometry
  52. GRB 021211, IR observations
  53. GRB 021211, optical observations
  54. GRB 021211: Optical Observations
  55. GRB021211: Kiso Observations
  56. GRB021204: Kiso Observations
  57. GRB 021201, optical observations
  58. GRB 021211: Radio Observations
  59. GRB 021201 (short/hard), NOT observations
  60. SUB-MM SEARCH FOR GRB 021211
  61. GRB 021211 Milagro GeV/TeV Observations
  62. GRB 021211, R- and I-band observations
  63. GRB021211 - Upper limits from recent and historical observations
  64. GRB 021204: I-band Observations
  65. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  66. HETE 2493: Optical observations
  67. GRB 021204: Optical Observations at RIKEN
  68. GRB 021125: Radio Observations
  69. IPN triangulation of GRB021206 (small error box)
  70. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  71. IPN detection of renewed activity from SGR1806-20
  72. IPN triangulation of GRB021205 (large error box)
  73. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  74. GRB021201, BVRcIc field photometry
  75. GRB 021201, Radio Observations
  76. GRB 021201: Optical Observations
  77. GRB 021201: BOOTES simultaneous optical observations
  78. IPN triangulation of GRB021201 (short/hard burst, small error box)
  79. Radio Catalog of GRB Afterglows
  80. GRB021004, late time optical observations
  81. GRB021004 Chandra Observation
  82. IPN detection of continued SGR1900+14 activity
  83. IPN triangulation of GRB021115 (annulus)
  84. IPN triangulation of GRB021125B (two large error boxes)
  85. IPN triangulation of GRB021119 (large error box)
  86. IPN triangulation of GRB021125B (annulus)
  87. Improved IPN error box for GRB021125
  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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