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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"

45478 results found.

  1. GRB021113: optical observations at Bisei
  2. GRB 021113: Evidence for a Dark Optical Afterglow
  3. GRB 021112, Radio Observations
  4. GRB021112, BVRI field photometry
  5. GRB 021112: Variable Source in R-band search
  6. GRB021112: Optical Observations
  7. GRB021113: Kiso Observations
  8. IPN triangulation of GRB021109 (portion of annulus)
  9. IPN triangulation of GRB021113 (=H2449; annulus)
  10. IPN triangulation of GRB021108 (CORRECTION; TWO LARGE ERROR BOXES)
  11. GRB 021113: Optical observations
  12. GRB 021112: RAPTOR Observations
  13. GRB 021113: Optical Observations
  14. GRB021113 (=H2449): A Long GRB Localized by HETE
  15. GRB 021112: Optical Observations
  16. GRB 021112: R-band search
  17. IPN triangulation of GRB021108 (large error box)
  18. GRB021112 (=H2448): A Long GRB Localized by HETE
  19. GRB 021016: Optical Observations
  20. IPN triangulation of GRB021109 (annulus)
  21. IPN triangulation of GRB021108 (annulus)
  22. GRB021004: Near infrared spectroscopy
  23. GRB021104: Optical Observations
  24. IPN triangulation of GRB021104 (annulus)
  25. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  26. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  27. SGR1900+14 activity, November 2-4, 2002
  28. Spectropolarimetry of GRB021004
  29. GRB021104: Optical observations
  30. GRB021104: optical observations
  31. GRB021104: Candidate present in DSS
  32. GRB021104: possible optical afterglow
  33. IPN triangulation of GRB021102 (annulus)
  34. Detection of activity from SGR 1900+14 with the RXTE/PCA
  35. IPN triangulation of a burst from SGR1900+14 on November 01, 2002
  36. IPN triangulation of a burst from SGR1900+14 on October 29 2002
  37. IPN triangulation of GRB021025 (portion of annulus)
  38. IPN triangulation of GRB021027 (single large error box)
  39. GRB021004, late-time optical observations
  40. IPN triangulation of GRB021027 (two large error boxes)
  41. IPN triangulation of GRB021027 (annulus)
  42. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  43. IPN triangulation of GRB021025 (annulus)
  44. IPN triangulation of SGR1900+14, October 22 2002
  45. GRB 021004: optical observations
  46. IPN triangulation of GRB021023 (small error boc)
  47. GRB021004: Optical Observations
  48. GRB 020813; likely host galaxy.
  49. IPN triangulation of GRB021020 (smaller error box)
  50. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  51. IPN triangulation of GRB021020
  52. GRB 021008, radio observations
  53. GRB 021016, optical observations
  54. GRB 021004: VRI observations at TNG: possible break
  55. GRB021016, optical observations
  56. SGR1900+14: burst on October 10 2002
  57. GRB 021008, optical observations
  58. GRB021016(=H2397): A Long GRB Localized by HETE
  59. IPN triangulation of GRB021016 (area corrected)
  60. IPN triangulation of GRB021016 (small error box)
  61. GRB021004: Optical Observations
  62. IPN triangulation of GRB021014 (large error box)
  63. IPN triangulation of GRB021013 (single error box)
  64. GRB 021004: optical spectroscopy on Oct 11
  65. IPN triangulation of GRB021013 (two small error boxes)
  66. GRB021004: High-resolution optical spectroscopy
  67. IPN triangulation of GRB021013 (annulus)
  68. XRF 020903: flattening of the optical light curve.
  69. GRB021004, UBVRcIc field photometry update
  70. IPN triangulation of GRB021008 (single error box)
  71. GRB021004: Optical Observations
  72. GRB 021004 submm observations
  73. IPN triangulation of GRB021008B (annulus)
  74. IPN triangulation of GRB021008 (two small error boxes)
  75. GRB021004 Chandra HETG Observations
  76. GRB 021004: Optical/NIR Observations
  77. GRB 021004: Additional V-band Polarimetric Observations
  78. GRB021004: optical observation
  79. GRB 021004: Host Galaxy Star Formation Rate
  80. GRB 021004 submm observations
  81. GRB 021004: WC wind?
  82. IPN triangulation of GRB021008
  83. GRB021004: NIR and Optical observations
  84. GRB 021004: Optical measurement at OHP
  85. GRB 021004: Optical observations, AUDE network
  86. GRB 021004 - VLA Radio Observations
  87. GRB 021004 - Unusual Radio-to-Submm Spectrum
  88. GRB 021004: optical spectroscopy
  89. IPN triangulation of GRB021007 (annulus)
  90. XRF 020903 spectrum
  91. GRB 021004: HST/STIS spectroscopic observations
  92. GRB021004: optical observations and predicted break time
  93. GRB021004: BVRc photometry
  94. GRB 021004 redshift
  95. GRB021004 radio observation
  96. GRB021004: restart of optical decay
  97. GRB 021004: Optical Decay
  98. GRB 021004 continued IR fading
  99. HETE fluences for GRB021004
  100. GRB 021004, spectroscopic observations

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