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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"

36147 results found.

  1. IPN triangulation of GRB030115B (annulus)
  2. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  3. Distribution of INTEGRAL SPI-ACS triggers
  4. GRB030115: R-band observations at Asiago
  5. GRB030115: TAROT optical observations
  6. GRB 021211: VLT spectrum
  7. GRB 030115: APO Optical Observations
  8. GRB 030115, no optical candidate
  9. GRB 030115, optical observations
  10. GRB 030115, optical candidate
  11. Possible GRB030113 seen by SPI ACS
  12. Probable GRB030112B seen by SPI ACS
  13. Probable GRB030112 seen by SPI ACS
  14. Possible GRB030111 seen by SPI ACS
  15. Possible GRB030110b seen by SPI ACS
  16. Possible GRB 030110 seen by SPI ACS
  17. IPN triangulation of GRB030109 (annulus)
  18. IPN triangulation of GRB030105 (large error box)
  19. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  20. Possible GRB 20030109 seen by SPI ACS
  21. IPN triangulation of GRB030102B (portion of annulus)
  22. IPN triangulation of GRB030102A (large error box)
  23. Possible GRB20030107 seen by SPI-ACS
  24. Possible GRB 20030105 seen by SPI ACS
  25. IPN triangulation of GRB030102 (annulus)
  26. GRB on 20030102 seen by SPI-ACS
  27. VLT spectroscopy of the probable host of GRB 021211
  28. GRB on 20030101 seen by SPI-ACS
  29. IPN triangulation of GRB030101 (two large error boxes)
  30. GRB021226
  31. GRB 021211: Probable Host and Underlying Supernova
  32. GRB 021226 registration by Helicon/Coronas-F
  33. Probable GRB in INTEGRAL SPI-ACS
  34. IPN triangulation of GRB021223 (two large error boxes)
  35. GRB021211, radio observations
  36. GRB 021112: Evidence for Another Dark Optical Afterglow
  37. GRB 021219: OSN optical observations
  38. GRB021219: Radio Observations
  39. IPN triangulation of GRB021219 - CORRECTION
  40. IPN triangulation of GRB021219
  41. GRB021219, optical observation by MASTER
  42. GRB021219: Correction to GCN 1766
  43. VLT spectra of GRB 021211 revisited
  44. GRB021219: a long GRB localized by INTEGRAL
  45. IPN detection of continued activity from SGR1806-20
  46. IPN triangulation of GRB021215 (large error box)
  47. IPN triangulation of GRB021214 (annulus)
  48. XRF 020903 : HST observations
  49. GRB 021201: Optical Observations
  50. GRB 021211, optical observations
  51. GRB 021211: CTIO observations
  52. GRB021211: Measurement of Early Time Afterglow
  53. VLT spectrum of GRB 021211
  54. IPN triangulation of GRB021211B (two large error boxes)
  55. GRB 021211: early break in light curve
  56. GRB021211, BVRI field photometry
  57. GRB 021211, IR observations
  58. GRB 021211, optical observations
  59. GRB 021211: Optical Observations
  60. GRB021211: Kiso Observations
  61. GRB021204: Kiso Observations
  62. GRB 021201, optical observations
  63. GRB 021211: Radio Observations
  64. GRB 021201 (short/hard), NOT observations
  65. SUB-MM SEARCH FOR GRB 021211
  66. GRB 021211 Milagro GeV/TeV Observations
  67. GRB 021211, R- and I-band observations
  68. GRB021211 - Upper limits from recent and historical observations
  69. GRB 021204: I-band Observations
  70. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  71. HETE 2493: Optical observations
  72. GRB 021204: Optical Observations at RIKEN
  73. GRB 021125: Radio Observations
  74. IPN triangulation of GRB021206 (small error box)
  75. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  76. IPN detection of renewed activity from SGR1806-20
  77. IPN triangulation of GRB021205 (large error box)
  78. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  79. GRB021201, BVRcIc field photometry
  80. GRB 021201, Radio Observations
  81. GRB 021201: Optical Observations
  82. GRB 021201: BOOTES simultaneous optical observations
  83. IPN triangulation of GRB021201 (short/hard burst, small error box)
  84. Radio Catalog of GRB Afterglows
  85. GRB021004, late time optical observations
  86. GRB021004 Chandra Observation
  87. IPN detection of continued SGR1900+14 activity
  88. IPN triangulation of GRB021115 (annulus)
  89. IPN triangulation of GRB021125B (two large error boxes)
  90. IPN triangulation of GRB021119 (large error box)
  91. IPN triangulation of GRB021125B (annulus)
  92. Improved IPN error box for GRB021125
  93. IPN triangulation of GRB021125 (INTEGRAL BURST)
  94. GRB021125 : A long GRB localized by INTEGRAL
  95. IPN confirmation of the reactivation of SGR1900+14
  96. IPN detection of possible reactivation of SGR1900+14
  97. GRB021113, SPI ACS observation
  98. IPN triangulation of GRB021119 (annulus)
  99. GRB 021112: Afterglow or Variable Star?
  100. GRB021113: optical observations at Bisei

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