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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"

35957 results found.

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

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