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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"

15564 results found.

  1. GRB 021201: Optical Observations
  2. GRB 021201: BOOTES simultaneous optical observations
  3. GRB021004, late time optical observations
  4. GRB 021112: Afterglow or Variable Star?
  5. GRB021113: optical observations at Bisei
  6. GRB 021113: Evidence for a Dark Optical Afterglow
  7. GRB 021112: Variable Source in R-band search
  8. GRB021112: Optical Observations
  9. GRB 021113: Optical observations
  10. GRB 021112: RAPTOR Observations
  11. GRB 021113: Optical Observations
  12. GRB 021113: Optical Observations
  13. GRB021113 (=H2449): A Long GRB Localized by HETE
  14. GRB 021112: Optical Observations
  15. GRB021112 (=H2448): A Long GRB Localized by HETE
  16. GRB 021016: Optical Observations
  17. GRB021104: Optical Observations
  18. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  19. GRB021104: Optical observations
  20. GRB021104: optical observations
  21. GRB021104: Candidate present in DSS
  22. GRB021104: possible optical afterglow
  23. GRB021004, late-time optical observations
  24. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  25. GRB 021004: optical observations
  26. GRB021004: Optical Observations
  27. GRB 020813; likely host galaxy.
  28. GRB021021(=XRF 021021): An X-ray Flash Localized by HETE
  29. GRB 021016, optical observations
  30. GRB 021004: VRI observations at TNG: possible break
  31. GRB021016, optical observations
  32. GRB 021008, optical observations
  33. GRB021016(=H2397): A Long GRB Localized by HETE
  34. GRB021004: Optical Observations
  35. GRB 021004: optical spectroscopy on Oct 11
  36. GRB021004: High-resolution optical spectroscopy
  37. XRF 020903: flattening of the optical light curve.
  38. GRB021004: Optical Observations
  39. GRB021004 Chandra HETG Observations
  40. GRB 021004: Optical/NIR Observations
  41. GRB 021004: Additional V-band Polarimetric Observations
  42. GRB021004: optical observation
  43. GRB 021004: WC wind?
  44. GRB021004: NIR and Optical observations
  45. GRB 021004: Optical measurement at OHP
  46. GRB 021004: Optical observations, AUDE network
  47. GRB 021004: optical spectroscopy
  48. XRF 020903 spectrum
  49. GRB021004: optical observations and predicted break time
  50. GRB021004: BVRc photometry
  51. GRB 021004 redshift
  52. GRB021004: restart of optical decay
  53. GRB 021004: Optical Decay
  54. GRB 021004 continued IR fading
  55. HETE fluences for GRB021004
  56. GRB 021004, spectroscopic observations
  57. GRB 021004: Optical Photometry at 2.5 Days
  58. GRB 021004: V-band Polarimetric Observations
  59. GRB 021004: Optical Decay
  60. GRB021004, astrometric position
  61. GRB021004, Optical Observations
  62. GRB 021004: Optical observations at RIKEN
  63. GRB 021004: Optical Observations
  64. GRB 021004: Optical Photometry at 1.5 Days
  65. GRB021004, Optical Observations
  66. GRB 021004: Optical observations
  67. GRB 021004: optical counterpart
  68. GRB 021004, optical observations
  69. GRB021004: Optical Spectroscopy
  70. GRB 021004: Optical Observations
  71. GRB 021004, SPM optical observations
  72. GRB 021004, optical observations
  73. GRB 021004: radio observations
  74. GRB 021004: steepening of the optical decay slope
  75. GRB021004: Upper limits from recent and historical observations
  76. GRB021004: optical observations at Nyrola
  77. GRB021004: Absorption redshift
  78. GRB021004(=H2380): Revised Localization with HETE Soft X-ray
  79. GRB021004: optical observations at Bisei
  80. GRB 021004: Kyoto observation
  81. GRB021004(=H2380): A Long GRB Localized by HETE in Near-Real Time
  82. GRB021004: Optical Afterglow
  83. GRB 020903: Optical observations at RIKEN
  84. XRF 020903: Archival Optical Images
  85. Radio Observations of XRF 020903: The Missing Link
  86. XRF 020903: Supernova
  87. GRB 020305: HST/STIS observations
  88. XRF 020903: optical observation at Kyoto
  89. GRB020322 : HST/STIS observations
  90. XRF 020903: Optical observations
  91. XRF 020903: Optical observations
  92. XRF 020903, optical observations
  93. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  94. GRB020813: optical observation
  95. GRB020812: optical observation
  96. GRB020819(=H2275): Revised Localization with HETE Soft X-ray
  97. SGR1900+14 burst localized by HETE
  98. GRB020813: High-resolution optical spectroscopy
  99. GRB020819: optical observations at Bisei
  100. GRB020812: negative optical observations

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