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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"

28060 results found.

  1. IPN triangulation of GRB021020 (smaller error box)
  2. IPN triangulation of GRB021020
  3. GRB 021008, optical observations
  4. IPN triangulation of GRB021016 (small error box)
  5. IPN triangulation of GRB021014 (large error box)
  6. IPN triangulation of GRB021013 (single error box)
  7. GRB 021004: optical spectroscopy on Oct 11
  8. IPN triangulation of GRB021013 (two small error boxes)
  9. GRB021004: High-resolution optical spectroscopy
  10. XRF 020903: flattening of the optical light curve.
  11. GRB021004, UBVRcIc field photometry update
  12. IPN triangulation of GRB021008 (single error box)
  13. GRB 021004 submm observations
  14. IPN triangulation of GRB021008 (two small error boxes)
  15. GRB021004 Chandra HETG Observations
  16. GRB 021004: Optical/NIR Observations
  17. GRB 021004: Additional V-band Polarimetric Observations
  18. GRB021004: optical observation
  19. GRB 021004: Host Galaxy Star Formation Rate
  20. GRB 021004 submm observations
  21. GRB 021004: WC wind?
  22. GRB021004: NIR and Optical observations
  23. GRB 021004: Optical observations, AUDE network
  24. GRB 021004 - VLA Radio Observations
  25. GRB 021004 - Unusual Radio-to-Submm Spectrum
  26. GRB 021004: optical spectroscopy
  27. IPN triangulation of GRB021007 (annulus)
  28. GRB021004: optical observations and predicted break time
  29. GRB021004: BVRc photometry
  30. GRB021004 radio observation
  31. HETE fluences for GRB021004
  32. GRB 021004: Optical Photometry at 2.5 Days
  33. GRB 021004: polarimetric observations
  34. GRB 021004: V-band Polarimetric Observations
  35. GRB021004: Update Bisei photometric data
  36. IRAM Millimeter detection of GRB 021004
  37. GRB 021004 radio observation
  38. GRB 021004: Optical Photometry at 1.5 Days
  39. GRB021004, BVRcIc field photometry
  40. GRB021004: Optical Spectroscopy
  41. GRB 021004 radio search
  42. XRF020903, BVRI field photometry
  43. XRF020903: TNG and Asiago photometry
  44. GRB 020903: Optical observations at RIKEN
  45. XRF 020903: Correction to GCN 1560
  46. XRF 020903: VRI observations
  47. XRF 020903: R band observations
  48. XRF 020903: Archival Optical Images
  49. Radio Observations of XRF 020903: The Missing Link
  50. XRF 020903: Supernova
  51. IPN triangulation of GRB020923 (two error boxes)
  52. IPN triangulation of GRB020914B
  53. IPN triangulation of GRB020911 (2 large error boxes)
  54. GRB 020305: HST/STIS observations
  55. Confirmation of IPN error box for GRB020910
  56. IPN triangulation of GRB020910
  57. IPN GCN Circulars now to be issued without restriction
  58. Single IPN error box for GRB020904
  59. XRF 020903: optical observation at Kyoto
  60. GRB020322 : HST/STIS observations
  61. XRF 020903: Optical observations
  62. IPN triangulation of GRB020904
  63. INTEGRAL GRBs added to GCN
  64. SGR1900+14 burst localized by HETE
  65. GRB020813: High-resolution optical spectroscopy
  66. GRB020812: negative optical observations
  67. GRB 020812: optical observation at Kyoto University
  68. Second epoch K band imaging of GRB 020819
  69. GRB 020813 : HST observations
  70. GRB 020812: early time optical observation at Ouda Station
  71. GRB020813: Magellan BVRI Photometry
  72. GRB 020819: Optical observations
  73. K band observation of GRB 020819
  74. GRB020813: optical and NIR observations
  75. GRB020813: Fading X-ray Afterglow Observed with Chandra
  76. GRB020813, UBVRI field calibration
  77. GRB020812: NIR observations
  78. Polarimetry of GRB020813: evidence for variability
  79. GRB020813 IRAM millimeter observations
  80. GRB020812: optical observations
  81. GRB020813: High-Resolution Optical Observations
  82. GRB 020812: optical observation at Bisei
  83. GRB020813: Early Time Magnitude
  84. Millimeter observation of GRB 020813
  85. GRB020812: optical observations
  86. GRB 020813 : KISO multiband optical observations
  87. GRB020813, optical observations
  88. IPN error box for GRB020813
  89. GRB020813, astrometric position
  90. Spectropolarimetry of GRB 020813
  91. GRB 020812 optical observation
  92. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  93. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  94. HST Imaging of the Host of GRB 011121
  95. GRB020801, optical afterglow candidate
  96. GRB020331: Late-time Optical Light Curve (re-submission)
  97. GRB020331: Late-time Optical Light Curve
  98. IPN triangulation of GRB020714
  99. IPN triangulation of GRB020715 (=GRB150702)
  100. IPN triangulation of GRB020714

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