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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"

36145 results found.

  1. GRB021112, BVRI field photometry
  2. GRB 021112: Variable Source in R-band search
  3. GRB021112: Optical Observations
  4. GRB021113: Kiso Observations
  5. IPN triangulation of GRB021109 (portion of annulus)
  6. IPN triangulation of GRB021113 (=H2449; annulus)
  7. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  8. GRB 021113: Optical observations
  9. GRB 021112: RAPTOR Observations
  10. GRB 021113: Optical Observations
  11. GRB 021113: Optical Observations
  12. GRB021113 (=H2449): A Long GRB Localized by HETE
  13. GRB 021112: Optical Observations
  14. GRB 021112: R-band search
  15. IPN triangulation of GRB021108 (large error box)
  16. GRB021112 (=H2448): A Long GRB Localized by HETE
  17. GRB 021016: Optical Observations
  18. IPN triangulation of GRB021109 (annulus)
  19. IPN triangulation of GRB021108 (annulus)
  20. IPN triangulation of GRB021104 (annulus)
  21. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  22. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  23. SGR1900+14 activity, November 2-4, 2002
  24. GRB021104: Candidate present in DSS
  25. IPN triangulation of GRB021102 (annulus)
  26. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  27. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  28. IPN triangulation of GRB021025 (portion of annulus)
  29. IPN triangulation of GRB021027 (single large error box)
  30. GRB021004, late-time optical observations
  31. IPN triangulation of GRB021027 (two large error boxes)
  32. GRB 021023: Infrared Imaging
  33. IPN triangulation of GRB021027 (annulus)
  34. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  35. IPN triangulation of GRB021025 (annulus)
  36. IPN triangulation of SGR1900+14, October 22 2002
  37. GRB 021004: optical observations
  38. IPN triangulation of GRB021023 (small error boc)
  39. GRB 020813; likely host galaxy.
  40. IPN triangulation of GRB021020 (smaller error box)
  41. IPN triangulation of GRB021020
  42. GRB 021008, radio observations
  43. GRB 021016, optical observations
  44. GRB 021004: VRI observations at TNG: possible break
  45. GRB021016, optical observations
  46. SGR1900+14: burst on October 10 2002
  47. GRB 021008, optical observations
  48. GRB021016(=H2397): A Long GRB Localized by HETE
  49. IPN triangulation of GRB021016 (small error box)
  50. IPN triangulation of GRB021014 (large error box)
  51. IPN triangulation of GRB021013 (single error box)
  52. GRB 021004: optical spectroscopy on Oct 11
  53. IPN triangulation of GRB021013 (two small error boxes)
  54. GRB021004: High-resolution optical spectroscopy
  55. IPN triangulation of GRB021013 (annulus)
  56. GRB021004, UBVRcIc field photometry update
  57. IPN triangulation of GRB021008 (single error box)
  58. GRB 021004 submm observations
  59. IPN triangulation of GRB021008B (annulus)
  60. IPN triangulation of GRB021008 (two small error boxes)
  61. GRB 021004: Optical/NIR Observations
  62. GRB 021004: Additional V-band Polarimetric Observations
  63. GRB021004: optical observation
  64. GRB 021004: Host Galaxy Star Formation Rate
  65. GRB 021004 submm observations
  66. GRB 021004: WC wind?
  67. IPN triangulation of GRB021008
  68. GRB 021004: Optical measurement at OHP
  69. GRB 021004: Optical observations, AUDE network
  70. GRB 021004 - VLA Radio Observations
  71. GRB 021004 - Unusual Radio-to-Submm Spectrum
  72. GRB 021004: optical spectroscopy
  73. IPN triangulation of GRB021007 (annulus)
  74. GRB 021004: HST/STIS spectroscopic observations
  75. GRB021004: optical observations and predicted break time
  76. GRB 021004 redshift
  77. GRB 021004: Optical Decay
  78. GRB 021004 continued IR fading
  79. HETE fluences for GRB021004
  80. GRB 021004, spectroscopic observations
  81. GRB021004: not fading anymore?
  82. GRB 021004: Optical Photometry at 2.5 Days
  83. GRB 021004: polarimetric observations
  84. GRB 021004: V-band Polarimetric Observations
  85. GRB 021004: Optical Decay
  86. GRB021004, astrometric position
  87. GRB021004, Optical Observations
  88. IRAM Millimeter detection of GRB 021004
  89. GRB 021004: Optical observations at RIKEN
  90. GRB 021004 radio observation
  91. GRB 021004: Optical Observations
  92. GRB021004: continued fading
  93. GRB 021004: Optical Photometry at 1.5 Days
  94. GRB021004, Optical Observations
  95. GRB021004, BVRcIc field photometry
  96. GRB 021004: Optical observations
  97. GRB 021004: optical counterpart
  98. GRB 021004, optical observations
  99. GRB021004: Optical Spectroscopy
  100. GRB 021004: Optical Observations

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