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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"

36155 results found.

  1. GRB030115, afterglow candidate
  2. GRB 021211: R-band observations at late-time
  3. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  4. IPN triangulation of GRB030115B (small error box)
  5. GRB 030115 : Possible IR counterpart
  6. GRB 030115: Radio Observations
  7. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  8. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  9. IPN triangulation of GRB030115B (annulus)
  10. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  11. Distribution of INTEGRAL SPI-ACS triggers
  12. GRB030115: R-band observations at Asiago
  13. GRB030115: TAROT optical observations
  14. GRB 021211: VLT spectrum
  15. GRB 030115: APO Optical Observations
  16. GRB 030115, no optical candidate
  17. GRB 030115, optical observations
  18. GRB 030115, optical candidate
  19. Possible GRB030113 seen by SPI ACS
  20. Probable GRB030112B seen by SPI ACS
  21. Probable GRB030112 seen by SPI ACS
  22. Possible GRB030111 seen by SPI ACS
  23. Possible GRB030110b seen by SPI ACS
  24. Possible GRB 030110 seen by SPI ACS
  25. IPN triangulation of GRB030109 (annulus)
  26. IPN triangulation of GRB030105 (large error box)
  27. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  28. Possible GRB 20030109 seen by SPI ACS
  29. IPN triangulation of GRB030102B (portion of annulus)
  30. IPN triangulation of GRB030102A (large error box)
  31. Possible GRB20030107 seen by SPI-ACS
  32. Possible GRB 20030105 seen by SPI ACS
  33. IPN triangulation of GRB030102 (annulus)
  34. GRB on 20030102 seen by SPI-ACS
  35. VLT spectroscopy of the probable host of GRB 021211
  36. GRB on 20030101 seen by SPI-ACS
  37. IPN triangulation of GRB030101 (two large error boxes)
  38. GRB021226
  39. GRB 021211: Probable Host and Underlying Supernova
  40. GRB 021226 registration by Helicon/Coronas-F
  41. Probable GRB in INTEGRAL SPI-ACS
  42. IPN triangulation of GRB021223 (two large error boxes)
  43. GRB021211, radio observations
  44. GRB 021112: Evidence for Another Dark Optical Afterglow
  45. GRB 021219: OSN optical observations
  46. GRB021219: Radio Observations
  47. IPN triangulation of GRB021219 - CORRECTION
  48. IPN triangulation of GRB021219
  49. GRB021219, optical observation by MASTER
  50. GRB021219: Correction to GCN 1766
  51. VLT spectra of GRB 021211 revisited
  52. GRB021219: a long GRB localized by INTEGRAL
  53. IPN detection of continued activity from SGR1806-20
  54. IPN triangulation of GRB021215 (large error box)
  55. IPN triangulation of GRB021214 (annulus)
  56. XRF 020903 : HST observations
  57. GRB 021201: Optical Observations
  58. GRB 021211, optical observations
  59. GRB 021211: CTIO observations
  60. GRB021211: Measurement of Early Time Afterglow
  61. VLT spectrum of GRB 021211
  62. IPN triangulation of GRB021211B (two large error boxes)
  63. GRB 021211: early break in light curve
  64. GRB021211, BVRI field photometry
  65. GRB 021211, IR observations
  66. GRB 021211, optical observations
  67. GRB 021211: Optical Observations
  68. GRB021211: Kiso Observations
  69. GRB021204: Kiso Observations
  70. GRB 021201, optical observations
  71. GRB 021211: Radio Observations
  72. GRB 021201 (short/hard), NOT observations
  73. SUB-MM SEARCH FOR GRB 021211
  74. GRB 021211 Milagro GeV/TeV Observations
  75. GRB 021211, R- and I-band observations
  76. GRB021211 - Upper limits from recent and historical observations
  77. GRB 021204: I-band Observations
  78. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  79. HETE 2493: Optical observations
  80. GRB 021204: Optical Observations at RIKEN
  81. GRB 021125: Radio Observations
  82. IPN triangulation of GRB021206 (small error box)
  83. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  84. IPN detection of renewed activity from SGR1806-20
  85. IPN triangulation of GRB021205 (large error box)
  86. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  87. GRB021201, BVRcIc field photometry
  88. GRB 021201, Radio Observations
  89. GRB 021201: Optical Observations
  90. GRB 021201: BOOTES simultaneous optical observations
  91. IPN triangulation of GRB021201 (short/hard burst, small error box)
  92. Radio Catalog of GRB Afterglows
  93. GRB021004, late time optical observations
  94. GRB021004 Chandra Observation
  95. IPN detection of continued SGR1900+14 activity
  96. IPN triangulation of GRB021115 (annulus)
  97. IPN triangulation of GRB021125B (two large error boxes)
  98. IPN triangulation of GRB021119 (large error box)
  99. IPN triangulation of GRB021125B (annulus)
  100. Improved IPN error box for GRB021125

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