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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"

35958 results found.

  1. IPN triangulation of GRB030117 (two large error boxes)
  2. Publicizing GRB Discoveries - A Message from NASA HQ
  3. GRB 030115: Radio detection of IR candidate
  4. GRB 030115, simultaneous observations by BOOTES-1
  5. GRB 030115: IR observations with IRSF/SIRIUS
  6. IPN triangulation of GRB030115C (large error box)
  7. GRB030115: R-band counterpart of IR candidate
  8. GRB030115, afterglow candidate
  9. GRB 021211: R-band observations at late-time
  10. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  11. IPN triangulation of GRB030115B (small error box)
  12. GRB 030115 : Possible IR counterpart
  13. GRB 030115: Radio Observations
  14. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  15. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  16. IPN triangulation of GRB030115B (annulus)
  17. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  18. Distribution of INTEGRAL SPI-ACS triggers
  19. GRB030115: R-band observations at Asiago
  20. GRB030115: TAROT optical observations
  21. GRB 021211: VLT spectrum
  22. GRB 030115: APO Optical Observations
  23. GRB 030115, no optical candidate
  24. GRB 030115, optical observations
  25. GRB 030115, optical candidate
  26. Possible GRB030113 seen by SPI ACS
  27. Probable GRB030112B seen by SPI ACS
  28. Probable GRB030112 seen by SPI ACS
  29. Possible GRB030111 seen by SPI ACS
  30. Possible GRB030110b seen by SPI ACS
  31. Possible GRB 030110 seen by SPI ACS
  32. IPN triangulation of GRB030109 (annulus)
  33. IPN triangulation of GRB030105 (large error box)
  34. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  35. Possible GRB 20030109 seen by SPI ACS
  36. IPN triangulation of GRB030102B (portion of annulus)
  37. IPN triangulation of GRB030102A (large error box)
  38. Possible GRB20030107 seen by SPI-ACS
  39. Possible GRB 20030105 seen by SPI ACS
  40. IPN triangulation of GRB030102 (annulus)
  41. GRB on 20030102 seen by SPI-ACS
  42. VLT spectroscopy of the probable host of GRB 021211
  43. GRB on 20030101 seen by SPI-ACS
  44. IPN triangulation of GRB030101 (two large error boxes)
  45. GRB021226
  46. GRB 021211: Probable Host and Underlying Supernova
  47. GRB 021226 registration by Helicon/Coronas-F
  48. Probable GRB in INTEGRAL SPI-ACS
  49. IPN triangulation of GRB021223 (two large error boxes)
  50. GRB021211, radio observations
  51. GRB 021112: Evidence for Another Dark Optical Afterglow
  52. GRB 021219: OSN optical observations
  53. GRB021219: Radio Observations
  54. IPN triangulation of GRB021219 - CORRECTION
  55. IPN triangulation of GRB021219
  56. GRB021219, optical observation by MASTER
  57. GRB021219: Correction to GCN 1766
  58. VLT spectra of GRB 021211 revisited
  59. GRB021219: a long GRB localized by INTEGRAL
  60. IPN detection of continued activity from SGR1806-20
  61. IPN triangulation of GRB021215 (large error box)
  62. IPN triangulation of GRB021214 (annulus)
  63. XRF 020903 : HST observations
  64. GRB 021201: Optical Observations
  65. GRB 021211, optical observations
  66. GRB 021211: CTIO observations
  67. GRB021211: Measurement of Early Time Afterglow
  68. VLT spectrum of GRB 021211
  69. IPN triangulation of GRB021211B (two large error boxes)
  70. GRB 021211: early break in light curve
  71. GRB021211, BVRI field photometry
  72. GRB 021211, IR observations
  73. GRB 021211, optical observations
  74. GRB 021211: Optical Observations
  75. GRB021211: Kiso Observations
  76. GRB021204: Kiso Observations
  77. GRB 021201, optical observations
  78. GRB 021211: Radio Observations
  79. GRB 021201 (short/hard), NOT observations
  80. SUB-MM SEARCH FOR GRB 021211
  81. GRB 021211 Milagro GeV/TeV Observations
  82. GRB 021211, R- and I-band observations
  83. GRB021211 - Upper limits from recent and historical observations
  84. GRB 021204: I-band Observations
  85. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  86. HETE 2493: Optical observations
  87. GRB 021204: Optical Observations at RIKEN
  88. GRB 021125: Radio Observations
  89. IPN triangulation of GRB021206 (small error box)
  90. IPN triangulation of GRB021206 (exceptionally bright; annulus only)
  91. IPN detection of renewed activity from SGR1806-20
  92. IPN triangulation of GRB021205 (large error box)
  93. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  94. GRB021201, BVRcIc field photometry
  95. GRB 021201, Radio Observations
  96. GRB 021201: Optical Observations
  97. GRB 021201: BOOTES simultaneous optical observations
  98. IPN triangulation of GRB021201 (short/hard burst, small error box)
  99. Radio Catalog of GRB Afterglows
  100. GRB021004, late time optical observations

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