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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: Candidate present in DSS
  2. GRB021104: possible optical afterglow
  3. IPN triangulation of GRB021102 (annulus)
  4. Detection of activity from SGR 1900+14 with the RXTE/PCA
  5. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  6. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  7. IPN triangulation of GRB021025 (portion of annulus)
  8. IPN triangulation of GRB021027 (single large error box)
  9. GRB021004, late-time optical observations
  10. IPN triangulation of GRB021027 (two large error boxes)
  11. GRB 021023: Infrared Imaging
  12. IPN triangulation of GRB021027 (annulus)
  13. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  14. IPN triangulation of GRB021025 (annulus)
  15. IPN triangulation of SGR1900+14, October 22 2002
  16. GRB 021004: optical observations
  17. IPN triangulation of GRB021023 (small error boc)
  18. GRB021004: Optical Observations
  19. GRB 020813; likely host galaxy.
  20. IPN triangulation of GRB021020 (smaller error box)
  21. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  22. IPN triangulation of GRB021020
  23. GRB 021008, radio observations
  24. GRB 021016, optical observations
  25. GRB 021004: VRI observations at TNG: possible break
  26. GRB021016, optical observations
  27. SGR1900+14: burst on October 10 2002
  28. GRB 021008, optical observations
  29. GRB021016(=H2397): A Long GRB Localized by HETE
  30. IPN triangulation of GRB021016 (area corrected)
  31. IPN triangulation of GRB021016 (small error box)
  32. GRB021004: Optical Observations
  33. IPN triangulation of GRB021014 (large error box)
  34. IPN triangulation of GRB021013 (single error box)
  35. GRB 021004: optical spectroscopy on Oct 11
  36. IPN triangulation of GRB021013 (two small error boxes)
  37. GRB021004: High-resolution optical spectroscopy
  38. IPN triangulation of GRB021013 (annulus)
  39. XRF 020903: flattening of the optical light curve.
  40. GRB021004, UBVRcIc field photometry update
  41. IPN triangulation of GRB021008 (single error box)
  42. GRB021004: Optical Observations
  43. GRB 021004 submm observations
  44. IPN triangulation of GRB021008B (annulus)
  45. IPN triangulation of GRB021008 (two small error boxes)
  46. GRB021004 Chandra HETG Observations
  47. GRB 021004: Optical/NIR Observations
  48. GRB 021004: Additional V-band Polarimetric Observations
  49. GRB021004: optical observation
  50. GRB 021004: Host Galaxy Star Formation Rate
  51. GRB 021004 submm observations
  52. GRB 021004: WC wind?
  53. IPN triangulation of GRB021008
  54. GRB021004: NIR and Optical observations
  55. GRB 021004: Optical measurement at OHP
  56. GRB 021004: Optical observations, AUDE network
  57. GRB 021004 - VLA Radio Observations
  58. GRB 021004 - Unusual Radio-to-Submm Spectrum
  59. GRB 021004: optical spectroscopy
  60. IPN triangulation of GRB021007 (annulus)
  61. XRF 020903 spectrum
  62. GRB 021004: HST/STIS spectroscopic observations
  63. GRB021004: optical observations and predicted break time
  64. GRB021004: BVRc photometry
  65. GRB 021004 redshift
  66. GRB021004 radio observation
  67. GRB021004: restart of optical decay
  68. GRB 021004: Optical Decay
  69. GRB 021004 continued IR fading
  70. HETE fluences for GRB021004
  71. GRB 021004, spectroscopic observations
  72. GRB021004: not fading anymore?
  73. GRB 021004: Optical Photometry at 2.5 Days
  74. GRB 021004: polarimetric observations
  75. GRB 021004: V-band Polarimetric Observations
  76. GRB021004: Update Bisei photometric data
  77. GRB 021004: Optical Decay
  78. GRB021004, astrometric position
  79. GRB021004, Optical Observations
  80. IRAM Millimeter detection of GRB 021004
  81. GRB 021004: Optical observations at RIKEN
  82. GRB 021004 radio observation
  83. GRB 021004: Optical Observations
  84. GRB021004: continued fading
  85. GRB 021004: Optical Photometry at 1.5 Days
  86. GRB021004, Optical Observations
  87. GRB021004, BVRcIc field photometry
  88. GRB 021004: Optical observations
  89. GRB 021004: optical counterpart
  90. GRB 021004, optical observations
  91. GRB021004: Optical Spectroscopy
  92. GRB 021004: Optical Observations
  93. GRB 021004, SPM optical observations
  94. GRB 021004, optical observations
  95. GRB 021004 radio search
  96. GRB 021004: radio observations
  97. GRB 021004: steepening of the optical decay slope
  98. GRB021004: Upper limits from recent and historical observations
  99. XRF020903, BVRI field photometry
  100. GRB021004: optical observations at Nyrola

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