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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"

32537 results found.

  1. Publicizing GRB Discoveries - A Message from NASA HQ
  2. GRB 030115, simultaneous observations by BOOTES-1
  3. GRB 030115: IR observations with IRSF/SIRIUS
  4. GRB030115: R-band counterpart of IR candidate
  5. GRB030115, afterglow candidate
  6. GRB 021211: R-band observations at late-time
  7. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  8. IPN triangulation of GRB030115B (small error box)
  9. GRB 030115 : Possible IR counterpart
  10. GRB 030115: Radio Observations
  11. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  12. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  13. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  14. Distribution of INTEGRAL SPI-ACS triggers
  15. GRB030115: TAROT optical observations
  16. GRB 021211: VLT spectrum
  17. GRB 030115: APO Optical Observations
  18. GRB 030115, no optical candidate
  19. GRB 030115, optical observations
  20. GRB 030115, optical candidate
  21. IPN triangulation of GRB030109 (annulus)
  22. IPN triangulation of GRB030105 (large error box)
  23. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  24. Coronas-F -Wind triangulation of GRB030102
  25. IPN triangulation of GRB030102 (annulus)
  26. VLT spectroscopy of the probable host of GRB 021211
  27. GRB021226
  28. GRB 021211: Probable Host and Underlying Supernova
  29. GRB 021226 registration by Helicon/Coronas-F
  30. GRB 021112: Evidence for Another Dark Optical Afterglow
  31. GRB 021219: OSN optical observations
  32. GRB021219: Radio Observations
  33. GRB021219, optical 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. GRB021211: APO optical observations
  41. IPN detection of continued activity from SGR1806-20
  42. XRF 020903 : HST observations
  43. GRB 021201: Optical Observations
  44. GRB 021211, optical observations
  45. GRB 021211: CTIO observations
  46. GRB021211: Measurement of Early Time Afterglow
  47. VLT spectrum of GRB 021211
  48. GRB 021211: early break in light curve
  49. GRB021211, BVRI field photometry
  50. GRB021211: Optical observations in CrAO
  51. GRB 021211, IR observations
  52. GRB 021211, optical observations
  53. GRB 021211: Optical Observations
  54. GRB021211: Kiso Observations
  55. GRB 021201, optical observations
  56. GRB 021211: Radio Observations
  57. GRB021211: Optical observations
  58. GRB 021201 (short/hard), NOT observations
  59. SUB-MM SEARCH FOR GRB 021211
  60. Chandra observation of the IPN error box of GRB021201 (short/hard)
  61. GRB 021211, R- and I-band observations
  62. GRB021211 - Upper limits from recent and historical observations
  63. GRB021211, OT at 108 s
  64. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  65. HETE 2493: Optical observations
  66. GRB 021125: Radio Observations
  67. IPN triangulation of GRB021206 (small error box)
  68. GRB 021104, GRB 021112 and GRB 021113 - Milagro GeV/TeV Observations
  69. GRB021201, BVRcIc field photometry
  70. GRB 021201, Radio Observations
  71. GRB 021201: Optical Observations
  72. GRB 021201: BOOTES simultaneous optical observations
  73. GRB021004, late time optical observations
  74. GRB021004 Chandra Observation
  75. GRB021125 refined position
  76. IPN triangulation of GRB021125B (two large error boxes)
  77. IPN triangulation of GRB021119 (large error box)
  78. Improved IPN error box for GRB021125
  79. IPN BURST POSITION
  80. IPN confirmation of the reactivation of SGR1900+14
  81. GRB021113, SPI ACS observation
  82. GRB 021112: Afterglow or Variable Star?
  83. GRB021113: optical observations at Bisei
  84. GRB 021113: Evidence for a Dark Optical Afterglow
  85. GRB 021112: Variable Source in R-band search
  86. GRB021112: Optical Observations
  87. IPN triangulation of GRB021109 (portion of annulus)
  88. IPN triangulation of GRB021113 (=H2449; annulus)
  89. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  90. GRB 021113: Optical Observations
  91. GRB 021113: Optical Observations
  92. GRB021113 (=H2449): A Long GRB Localized by HETE
  93. GRB 021112: Optical Observations
  94. GRB 021112: R-band search
  95. IPN triangulation of GRB021108 (large error box)
  96. GRB021112 (=H2448): A Long GRB Localized by HETE
  97. GRB 021016: Optical Observations
  98. GRB021004: Near infrared spectroscopy
  99. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  100. Spectropolarimetry of GRB021004

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