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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"
  1. GRB 021004: optical observations
  2. IPN triangulation of GRB021023 (small error boc)
  3. GRB021004: Optical Observations
  4. GRB 020813; likely host galaxy.
  5. IPN triangulation of GRB021020 (smaller error box)
  6. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  7. IPN triangulation of GRB021020
  8. GRB 021008, radio observations
  9. GRB 021016, optical observations
  10. GRB 021004: VRI observations at TNG: possible break
  11. GRB021016, optical observations
  12. SGR1900+14: burst on October 10 2002
  13. GRB 021008, optical observations
  14. GRB021016(=H2397): A Long GRB Localized by HETE
  15. IPN triangulation of GRB021016 (area corrected)
  16. IPN triangulation of GRB021016 (small error box)
  17. GRB021004: Optical Observations
  18. IPN triangulation of GRB021014 (large error box)
  19. IPN triangulation of GRB021013 (single error box)
  20. GRB 021004: optical spectroscopy on Oct 11
  21. IPN triangulation of GRB021013 (two small error boxes)
  22. GRB021004: High-resolution optical spectroscopy
  23. IPN triangulation of GRB021013 (annulus)
  24. XRF 020903: flattening of the optical light curve.
  25. GRB021004, UBVRcIc field photometry update
  26. IPN triangulation of GRB021008 (single error box)
  27. GRB021004: Optical Observations
  28. GRB 021004 submm observations
  29. IPN triangulation of GRB021008B (annulus)
  30. IPN triangulation of GRB021008 (two small error boxes)
  31. GRB021004 Chandra HETG Observations
  32. GRB 021004: Optical/NIR Observations
  33. GRB 021004: Additional V-band Polarimetric Observations
  34. GRB021004: optical observation
  35. GRB 021004: Host Galaxy Star Formation Rate
  36. GRB 021004 submm observations
  37. GRB 021004: WC wind?
  38. IPN triangulation of GRB021008
  39. GRB021004: NIR and Optical observations
  40. GRB 021004: Optical measurement at OHP
  41. GRB 021004: Optical observations, AUDE network
  42. GRB 021004 - VLA Radio Observations
  43. GRB 021004 - Unusual Radio-to-Submm Spectrum
  44. GRB 021004: optical spectroscopy
  45. IPN triangulation of GRB021007 (annulus)
  46. XRF 020903 spectrum
  47. GRB 021004: HST/STIS spectroscopic observations
  48. GRB021004: optical observations and predicted break time
  49. GRB021004: BVRc photometry
  50. GRB 021004 redshift
  51. GRB021004 radio observation
  52. GRB021004: restart of optical decay
  53. GRB 021004: Optical Decay
  54. GRB 021004 continued IR fading
  55. HETE fluences for GRB021004
  56. GRB 021004, spectroscopic observations
  57. GRB021004: not fading anymore?
  58. GRB 021004: Optical Photometry at 2.5 Days
  59. GRB 021004: polarimetric observations
  60. GRB 021004: V-band Polarimetric Observations
  61. GRB021004: Update Bisei photometric data
  62. GRB 021004: Optical Decay
  63. GRB021004, astrometric position
  64. GRB021004, Optical Observations
  65. IRAM Millimeter detection of GRB 021004
  66. GRB 021004: Optical observations at RIKEN
  67. GRB 021004 radio observation
  68. GRB 021004: Optical Observations
  69. GRB021004: continued fading
  70. GRB 021004: Optical Photometry at 1.5 Days
  71. GRB021004, Optical Observations
  72. GRB021004, BVRcIc field photometry
  73. GRB 021004: Optical observations
  74. GRB 021004: optical counterpart
  75. GRB 021004, optical observations
  76. GRB021004: Optical Spectroscopy
  77. GRB 021004: Optical Observations
  78. GRB 021004, SPM optical observations
  79. GRB 021004, optical observations
  80. GRB 021004 radio search
  81. GRB 021004: radio observations
  82. GRB 021004: steepening of the optical decay slope
  83. GRB021004: Upper limits from recent and historical observations
  84. XRF020903, BVRI field photometry
  85. GRB021004: optical observations at Nyrola
  86. GRB021004: Absorption redshift
  87. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  88. GRB021004: optical observations at Bisei
  89. GRB 021004: Kyoto observation
  90. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  91. GRB021004: Optical Afterglow
  92. XRF020903: TNG and Asiago photometry
  93. GRB 020903: Optical observations at RIKEN
  94. XRF 020903: Correction to GCN 1560
  95. XRF 020903: VRI observations
  96. IPN triangulation of GRB020926 (single large error box)
  97. GRB 020903: correction to GCN 1557
  98. XRF 020903: R band observations
  99. XRF 020903: Archival Optical Images
  100. Radio Observations of XRF 020903: The Missing Link

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