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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. Spectropolarimetry of GRB021004
  2. GRB021104: Optical observations
  3. GRB021104: optical observations
  4. GRB021104: Candidate present in DSS
  5. GRB021104: possible optical afterglow
  6. IPN triangulation of GRB021102 (annulus)
  7. Detection of activity from SGR 1900+14 with the RXTE/PCA
  8. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  9. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  10. IPN triangulation of GRB021025 (portion of annulus)
  11. IPN triangulation of GRB021027 (single large error box)
  12. GRB021004, late-time optical observations
  13. IPN triangulation of GRB021027 (two large error boxes)
  14. GRB 021023: Infrared Imaging
  15. IPN triangulation of GRB021027 (annulus)
  16. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  17. IPN triangulation of GRB021025 (annulus)
  18. IPN triangulation of SGR1900+14, October 22 2002
  19. GRB 021004: optical observations
  20. IPN triangulation of GRB021023 (small error boc)
  21. GRB021004: Optical Observations
  22. GRB 020813; likely host galaxy.
  23. IPN triangulation of GRB021020 (smaller error box)
  24. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  25. IPN triangulation of GRB021020
  26. GRB 021008, radio observations
  27. GRB 021016, optical observations
  28. GRB 021004: VRI observations at TNG: possible break
  29. GRB021016, optical observations
  30. SGR1900+14: burst on October 10 2002
  31. GRB 021008, optical observations
  32. GRB021016(=H2397): A Long GRB Localized by HETE
  33. IPN triangulation of GRB021016 (area corrected)
  34. IPN triangulation of GRB021016 (small error box)
  35. GRB021004: Optical Observations
  36. IPN triangulation of GRB021014 (large error box)
  37. IPN triangulation of GRB021013 (single error box)
  38. GRB 021004: optical spectroscopy on Oct 11
  39. IPN triangulation of GRB021013 (two small error boxes)
  40. GRB021004: High-resolution optical spectroscopy
  41. IPN triangulation of GRB021013 (annulus)
  42. XRF 020903: flattening of the optical light curve.
  43. GRB021004, UBVRcIc field photometry update
  44. IPN triangulation of GRB021008 (single error box)
  45. GRB021004: Optical Observations
  46. GRB 021004 submm observations
  47. IPN triangulation of GRB021008B (annulus)
  48. IPN triangulation of GRB021008 (two small error boxes)
  49. GRB021004 Chandra HETG Observations
  50. GRB 021004: Optical/NIR Observations
  51. GRB 021004: Additional V-band Polarimetric Observations
  52. GRB021004: optical observation
  53. GRB 021004: Host Galaxy Star Formation Rate
  54. GRB 021004 submm observations
  55. GRB 021004: WC wind?
  56. IPN triangulation of GRB021008
  57. GRB021004: NIR and Optical observations
  58. GRB 021004: Optical measurement at OHP
  59. GRB 021004: Optical observations, AUDE network
  60. GRB 021004 - VLA Radio Observations
  61. GRB 021004 - Unusual Radio-to-Submm Spectrum
  62. GRB 021004: optical spectroscopy
  63. IPN triangulation of GRB021007 (annulus)
  64. XRF 020903 spectrum
  65. GRB 021004: HST/STIS spectroscopic observations
  66. GRB021004: optical observations and predicted break time
  67. GRB021004: BVRc photometry
  68. GRB 021004 redshift
  69. GRB021004 radio observation
  70. GRB021004: restart of optical decay
  71. GRB 021004: Optical Decay
  72. GRB 021004 continued IR fading
  73. HETE fluences for GRB021004
  74. GRB 021004, spectroscopic observations
  75. GRB021004: not fading anymore?
  76. GRB 021004: Optical Photometry at 2.5 Days
  77. GRB 021004: polarimetric observations
  78. GRB 021004: V-band Polarimetric Observations
  79. GRB021004: Update Bisei photometric data
  80. GRB 021004: Optical Decay
  81. GRB021004, astrometric position
  82. GRB021004, Optical Observations
  83. IRAM Millimeter detection of GRB 021004
  84. GRB 021004: Optical observations at RIKEN
  85. GRB 021004 radio observation
  86. GRB 021004: Optical Observations
  87. GRB021004: continued fading
  88. GRB 021004: Optical Photometry at 1.5 Days
  89. GRB021004, Optical Observations
  90. GRB021004, BVRcIc field photometry
  91. GRB 021004: Optical observations
  92. GRB 021004: optical counterpart
  93. GRB 021004, optical observations
  94. GRB021004: Optical Spectroscopy
  95. GRB 021004: Optical Observations
  96. GRB 021004, SPM optical observations
  97. GRB 021004, optical observations
  98. GRB 021004 radio search
  99. GRB 021004: radio observations
  100. GRB 021004: steepening of the optical decay slope

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