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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. GRB021104: Optical Observations
  2. IPN triangulation of GRB021104 (annulus)
  3. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  4. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  5. SGR1900+14 activity, November 2-4, 2002
  6. Spectropolarimetry of GRB021004
  7. GRB021104: Optical observations
  8. GRB021104: optical observations
  9. GRB021104: Candidate present in DSS
  10. GRB021104: possible optical afterglow
  11. IPN triangulation of GRB021102 (annulus)
  12. Detection of activity from SGR 1900+14 with the RXTE/PCA
  13. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  14. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  15. IPN triangulation of GRB021025 (portion of annulus)
  16. IPN triangulation of GRB021027 (single large error box)
  17. GRB021004, late-time optical observations
  18. IPN triangulation of GRB021027 (two large error boxes)
  19. GRB 021023: Infrared Imaging
  20. IPN triangulation of GRB021027 (annulus)
  21. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  22. IPN triangulation of GRB021025 (annulus)
  23. IPN triangulation of SGR1900+14, October 22 2002
  24. GRB 021004: optical observations
  25. IPN triangulation of GRB021023 (small error boc)
  26. GRB021004: Optical Observations
  27. GRB 020813; likely host galaxy.
  28. IPN triangulation of GRB021020 (smaller error box)
  29. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  30. IPN triangulation of GRB021020
  31. GRB 021008, radio observations
  32. GRB 021016, optical observations
  33. GRB 021004: VRI observations at TNG: possible break
  34. GRB021016, optical observations
  35. SGR1900+14: burst on October 10 2002
  36. GRB 021008, optical observations
  37. GRB021016(=H2397): A Long GRB Localized by HETE
  38. IPN triangulation of GRB021016 (area corrected)
  39. IPN triangulation of GRB021016 (small error box)
  40. GRB021004: Optical Observations
  41. IPN triangulation of GRB021014 (large error box)
  42. IPN triangulation of GRB021013 (single error box)
  43. GRB 021004: optical spectroscopy on Oct 11
  44. IPN triangulation of GRB021013 (two small error boxes)
  45. GRB021004: High-resolution optical spectroscopy
  46. IPN triangulation of GRB021013 (annulus)
  47. XRF 020903: flattening of the optical light curve.
  48. GRB021004, UBVRcIc field photometry update
  49. IPN triangulation of GRB021008 (single error box)
  50. GRB021004: Optical Observations
  51. GRB 021004 submm observations
  52. IPN triangulation of GRB021008B (annulus)
  53. IPN triangulation of GRB021008 (two small error boxes)
  54. GRB021004 Chandra HETG Observations
  55. GRB 021004: Optical/NIR Observations
  56. GRB 021004: Additional V-band Polarimetric Observations
  57. GRB021004: optical observation
  58. GRB 021004: Host Galaxy Star Formation Rate
  59. GRB 021004 submm observations
  60. GRB 021004: WC wind?
  61. IPN triangulation of GRB021008
  62. GRB021004: NIR and Optical observations
  63. GRB 021004: Optical measurement at OHP
  64. GRB 021004: Optical observations, AUDE network
  65. GRB 021004 - VLA Radio Observations
  66. GRB 021004 - Unusual Radio-to-Submm Spectrum
  67. GRB 021004: optical spectroscopy
  68. IPN triangulation of GRB021007 (annulus)
  69. XRF 020903 spectrum
  70. GRB 021004: HST/STIS spectroscopic observations
  71. GRB021004: optical observations and predicted break time
  72. GRB021004: BVRc photometry
  73. GRB 021004 redshift
  74. GRB021004 radio observation
  75. GRB021004: restart of optical decay
  76. GRB 021004: Optical Decay
  77. GRB 021004 continued IR fading
  78. HETE fluences for GRB021004
  79. GRB 021004, spectroscopic observations
  80. GRB021004: not fading anymore?
  81. GRB 021004: Optical Photometry at 2.5 Days
  82. GRB 021004: polarimetric observations
  83. GRB 021004: V-band Polarimetric Observations
  84. GRB021004: Update Bisei photometric data
  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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