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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"

35264 results found.

  1. GRB 021201, Radio Observations
  2. GRB 021201: Optical Observations
  3. GRB 021201: BOOTES simultaneous optical observations
  4. IPN triangulation of GRB021201 (short/hard burst, small error box)
  5. Radio Catalog of GRB Afterglows
  6. GRB021004, late time optical observations
  7. GRB021004 Chandra Observation
  8. IPN detection of continued SGR1900+14 activity
  9. IPN triangulation of GRB021115 (annulus)
  10. IPN triangulation of GRB021125B (two large error boxes)
  11. IPN triangulation of GRB021119 (large error box)
  12. IPN triangulation of GRB021125B (annulus)
  13. Improved IPN error box for GRB021125
  14. IPN triangulation of GRB021125 (INTEGRAL BURST)
  15. GRB021125 : A long GRB localized by INTEGRAL
  16. IPN confirmation of the reactivation of SGR1900+14
  17. IPN detection of possible reactivation of SGR1900+14
  18. GRB021113, SPI ACS observation
  19. IPN triangulation of GRB021119 (annulus)
  20. GRB 021112: Afterglow or Variable Star?
  21. GRB021113: optical observations at Bisei
  22. GRB 021113: Evidence for a Dark Optical Afterglow
  23. GRB 021112, Radio Observations
  24. GRB021112, BVRI field photometry
  25. GRB 021112: Variable Source in R-band search
  26. GRB021112: Optical Observations
  27. GRB021113: Kiso Observations
  28. IPN triangulation of GRB021109 (portion of annulus)
  29. IPN triangulation of GRB021113 (=H2449; annulus)
  30. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  31. GRB 021113: Optical observations
  32. GRB 021112: RAPTOR Observations
  33. GRB 021113: Optical Observations
  34. GRB 021113: Optical Observations
  35. GRB021113 (=H2449): A Long GRB Localized by HETE
  36. GRB 021112: Optical Observations
  37. GRB 021112: R-band search
  38. IPN triangulation of GRB021108 (large error box)
  39. GRB021112 (=H2448): A Long GRB Localized by HETE
  40. GRB 021016: Optical Observations
  41. IPN triangulation of GRB021109 (annulus)
  42. IPN triangulation of GRB021108 (annulus)
  43. IPN triangulation of GRB021104 (annulus)
  44. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  45. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  46. SGR1900+14 activity, November 2-4, 2002
  47. GRB021104: Candidate present in DSS
  48. IPN triangulation of GRB021102 (annulus)
  49. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  50. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  51. IPN triangulation of GRB021025 (portion of annulus)
  52. IPN triangulation of GRB021027 (single large error box)
  53. GRB021004, late-time optical observations
  54. IPN triangulation of GRB021027 (two large error boxes)
  55. GRB 021023: Infrared Imaging
  56. IPN triangulation of GRB021027 (annulus)
  57. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  58. IPN triangulation of GRB021025 (annulus)
  59. IPN triangulation of SGR1900+14, October 22 2002
  60. GRB 021004: optical observations
  61. IPN triangulation of GRB021023 (small error boc)
  62. GRB 020813; likely host galaxy.
  63. IPN triangulation of GRB021020 (smaller error box)
  64. IPN triangulation of GRB021020
  65. GRB 021008, radio observations
  66. GRB 021016, optical observations
  67. GRB 021004: VRI observations at TNG: possible break
  68. GRB021016, optical observations
  69. SGR1900+14: burst on October 10 2002
  70. GRB 021008, optical observations
  71. GRB021016(=H2397): A Long GRB Localized by HETE
  72. IPN triangulation of GRB021016 (small error box)
  73. IPN triangulation of GRB021014 (large error box)
  74. IPN triangulation of GRB021013 (single error box)
  75. GRB 021004: optical spectroscopy on Oct 11
  76. IPN triangulation of GRB021013 (two small error boxes)
  77. GRB021004: High-resolution optical spectroscopy
  78. IPN triangulation of GRB021013 (annulus)
  79. GRB021004, UBVRcIc field photometry update
  80. IPN triangulation of GRB021008 (single error box)
  81. GRB 021004 submm observations
  82. IPN triangulation of GRB021008B (annulus)
  83. IPN triangulation of GRB021008 (two small error boxes)
  84. GRB 021004: Optical/NIR Observations
  85. GRB 021004: Additional V-band Polarimetric Observations
  86. GRB021004: optical observation
  87. GRB 021004: Host Galaxy Star Formation Rate
  88. GRB 021004 submm observations
  89. GRB 021004: WC wind?
  90. IPN triangulation of GRB021008
  91. GRB 021004: Optical measurement at OHP
  92. GRB 021004: Optical observations, AUDE network
  93. GRB 021004 - VLA Radio Observations
  94. GRB 021004 - Unusual Radio-to-Submm Spectrum
  95. GRB 021004: optical spectroscopy
  96. IPN triangulation of GRB021007 (annulus)
  97. GRB 021004: HST/STIS spectroscopic observations
  98. GRB021004: optical observations and predicted break time
  99. GRB 021004 redshift
  100. GRB 021004: Optical Decay

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