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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"

23639 results found.

  1. GRB030226: Optical observations at Asiago
  2. IPN triangulation of GRB030306 (two small error boxes)
  3. IPN triangulation of GRB030306 (intense; annulus only so far)
  4. GRB 030226: Optical observations
  5. GRB030226: Analysis of Chandra data
  6. GRB 030227: Optical observations
  7. GRB030226, BVRc observations
  8. Chandra detection of the X-ray afterglow of GRB 030226
  9. GRB 030226, further optical/NIR imaging
  10. GRB 030226: Ic Observations
  11. GRB030227: Kiso optical upper limit
  12. GRB 030227 optical afterglow
  13. 030302: NOT A GRB
  14. 030228: NOT A GRB
  15. GRB 030226: Steep Decline
  16. GRB 030227: Confirmed Optical Afterglow (S1-A)
  17. GRB 030226: Optical observations
  18. GRB030227:Optical observations
  19. GRB 030227, possible optical counterpart of XMM-Newton source
  20. GRB030227: Kiso optical observations
  21. GRB 030226, optical light curve
  22. GRB030227: refined INTEGRAL position
  23. GRB030227 localized by INTEGRAL
  24. Possible break in the GRB 030226 light curve
  25. GRB 030226 : Predicted light curve
  26. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  27. GRB 030226 simultaneous optical observations
  28. Two absorption systems in GRB 030226
  29. GRB 030226 Optical Spectra and R,I,z' Imaging
  30. GRB: Non-Referencing of GCN Circulars.
  31. GRB 030131: marginal optical detection
  32. GRB 030204: Optical Observations
  33. GRB030131: Candidate Optical Afterglow
  34. GRB 030204, optical observations
  35. GRB 030131, optical observations
  36. GRB030131: Kiso optical limit for corrected position
  37. GRB030131: Optical limits for corrected position
  38. GRB 030115, late-time optical observations
  39. GRB030131: corrected INTEGRAL position
  40. GRB030131: Kiso Observations
  41. GRB 020819: Host galaxy at Radio Position
  42. IPN triangulation of GRB030131
  43. GRB030131: Optical limit
  44. GRB030131: refined position
  45. A long GRB detected by INTEGRAL
  46. IPN triangulation of GRB030119 (two large error boxes)
  47. IPN triangulation of GRB030117 (two large error boxes)
  48. Publicizing GRB Discoveries - A Message from NASA HQ
  49. GRB 030115, simultaneous observations by BOOTES-1
  50. GRB030115: R-band counterpart of IR candidate
  51. GRB 021211: R-band observations at late-time
  52. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  53. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  54. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  55. GRB 021211: VLT spectrum
  56. Information about where HETE will be pointing
  57. IPN triangulation of GRB030105 (large error box)
  58. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  59. VLT spectroscopy of the probable host of GRB 021211
  60. IPN triangulation of GRB030101 (two large error boxes)
  61. GRB021219, optical observations
  62. GRB021219, optical observation by MASTER
  63. XRF 020903 : HST observations
  64. GRB 021211: CTIO observations
  65. GRB021211: Measurement of Early Time Afterglow
  66. VLT spectrum of GRB 021211
  67. IPN triangulation of GRB021211B (two large error boxes)
  68. GRB 021211: early break in light curve
  69. GRB021204: Kiso Observations
  70. GRB 021211, R- and I-band observations
  71. GRB021211, OT at 108 s
  72. GRB021211 (HETE2493), OT at 143 sec
  73. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  74. GRB 021204: Optical Observations at RIKEN
  75. IPN detection of renewed activity from SGR1806-20
  76. GRB 021201: BOOTES simultaneous optical observations
  77. Radio Catalog of GRB Afterglows
  78. GRB021004, late time optical observations
  79. GRB021004 Chandra Observation
  80. IPN triangulation of GRB021119 (large error box)
  81. IPN BURST POSITION
  82. IPN triangulation of GRB021125 (INTEGRAL BURST)
  83. IPN confirmation of the reactivation of SGR1900+14
  84. IPN detection of possible reactivation of SGR1900+14
  85. GRB021113, SPI ACS observation
  86. GRB 021112: Afterglow or Variable Star?
  87. GRB 021112: Variable Source in R-band search
  88. GRB021113: Kiso Observations
  89. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  90. GRB 021112: RAPTOR Observations
  91. GRB 021113: Optical Observations
  92. GRB021113 (=H2449): A Long GRB Localized by HETE
  93. GRB 021112: R-band search
  94. IPN triangulation of GRB021108 (large error box)
  95. GRB021112 (=H2448): A Long GRB Localized by HETE
  96. GRB021004: Near infrared spectroscopy
  97. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  98. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  99. SGR1900+14 activity, November 2-4, 2002
  100. GRB021104: optical observations

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