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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"

32502 results found.

  1. GRB 021004: Optical/NIR Observations
  2. GRB 021004: Additional V-band Polarimetric Observations
  3. GRB021004: optical observation
  4. GRB 021004: Host Galaxy Star Formation Rate
  5. GRB 021004 submm observations
  6. GRB 021004: WC wind?
  7. GRB021004: NIR and Optical observations
  8. GRB 021004: Optical measurement at OHP
  9. GRB 021004: Optical observations, AUDE network
  10. GRB 021004 - VLA Radio Observations
  11. GRB 021004 - Unusual Radio-to-Submm Spectrum
  12. XRF 020903 spectrum
  13. GRB021004: optical observations and predicted break time
  14. GRB021004: BVRc photometry
  15. GRB 021004 redshift
  16. GRB021004: restart of optical decay
  17. GRB 021004: Optical Decay
  18. GRB 021004, spectroscopic observations
  19. GRB021004: not fading anymore?
  20. GRB 021004: Optical Photometry at 2.5 Days
  21. GRB 021004: polarimetric observations
  22. GRB 021004: V-band Polarimetric Observations
  23. GRB021004: Update Bisei photometric data
  24. GRB 021004: Optical Decay
  25. GRB021004, astrometric position
  26. GRB021004, Optical Observations
  27. IRAM Millimeter detection of GRB 021004
  28. GRB 021004: Optical observations at RIKEN
  29. GRB 021004 radio observation
  30. GRB 021004: Optical Observations
  31. GRB021004: continued fading
  32. GRB 021004: Optical Photometry at 1.5 Days
  33. GRB021004, Optical Observations
  34. GRB021004, BVRcIc field photometry
  35. GRB 021004: Optical observations
  36. GRB 021004: optical counterpart
  37. GRB 021004, optical observations
  38. GRB021004: Optical Spectroscopy
  39. GRB 021004: Optical Observations
  40. GRB 021004, SPM optical observations
  41. GRB 021004, optical observations
  42. GRB 021004 radio search
  43. GRB 021004: radio observations
  44. GRB 021004: steepening of the optical decay slope
  45. GRB021004: Upper limits from recent and historical observations
  46. XRF020903, BVRI field photometry
  47. GRB021004: optical observations at Nyrola
  48. GRB021004: Absorption redshift
  49. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  50. GRB021004: optical observations at Bisei
  51. GRB 021004: Kyoto observation
  52. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  53. XRF020903: TNG and Asiago photometry
  54. GRB 020903: Optical observations at RIKEN
  55. XRF 020903: Correction to GCN 1560
  56. XRF 020903: VRI observations
  57. IPN triangulation of GRB020926 (single large error box)
  58. GRB 020903: correction to GCN 1557
  59. XRF 020903: R band observations
  60. XRF 020903: Archival Optical Images
  61. Radio Observations of XRF 020903: The Missing Link
  62. XRF 020903: Supernova
  63. GRB020924 (ecliptic latitude-only localization)
  64. IPN triangulation of GRB020923 (two error boxes)
  65. IPN triangulation of GRB020914B
  66. Improved IPN position for GRB020918 (two large error boxes)
  67. IPN annulus for GRB020914B
  68. IPN triangulation of GRB020914 - clarification and additional information
  69. IPN triangulation of GRB020914
  70. GRB 020305: HST/STIS observations
  71. Confirmation of IPN error box for GRB020910
  72. IPN GCN Circulars now to be issued without restriction
  73. Single IPN error box for GRB020904
  74. XRF 020903: optical observation at Kyoto
  75. GRB020322 : HST/STIS observations
  76. XRF 020903: Optical observations
  77. IPN triangulation of GRB020904
  78. XRF 020903: Optical observations
  79. XRF 020903, optical observations
  80. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  81. INTEGRAL GRBs added to GCN
  82. GRB020813: optical observation
  83. GRB020812: optical observation
  84. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  85. GRB020813: High-resolution optical spectroscopy
  86. GRB020819: optical observations at Bisei
  87. GRB020812: negative optical observations
  88. GRB 020812: optical observation at Kyoto University
  89. Second epoch K band imaging of GRB 020819
  90. GRB020813, Baade 6.5m data now available
  91. GRB 020813 : HST observations
  92. Confirming no variability for GRB02081
  93. GRB 020812: early time optical observation at Ouda Station
  94. GRB020813: VRI Decay Slopes
  95. GRB 020819 : OT candidate - confirmation of non variability
  96. GRB 020819: Optical observations
  97. K band observation of GRB 020819
  98. GRB020819: optical observations
  99. GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
  100. HETE 2275: Optical observations

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