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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"

24781 results found.

  1. GRB 021113: Evidence for a Dark Optical Afterglow
  2. GRB021112, BVRI field photometry
  3. GRB 021112: Variable Source in R-band search
  4. GRB021112: Optical Observations
  5. IPN triangulation of GRB021113 (=H2449; annulus)
  6. GRB 021113: Optical observations
  7. GRB 021112: RAPTOR Observations
  8. GRB021113 (=H2449): A Long GRB Localized by HETE
  9. GRB021112 (=H2448): A Long GRB Localized by HETE
  10. GRB 021016: Optical Observations
  11. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  12. IPN triangulation of bursts from SGR1900+14, November 1-2, 2002
  13. SGR1900+14 activity, November 2-4, 2002
  14. GRB021104: optical observations
  15. Detection of activity from SGR 1900+14 with the RXTE/PCA
  16. IPN triangulation of GRB021027 (single large error box)
  17. IPN triangulation of GRB021027 (two large error boxes)
  18. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  19. GRB 021004: optical observations
  20. IPN triangulation of GRB021023 (small error boc)
  21. GRB 020813; likely host galaxy.
  22. IPN triangulation of GRB021020 (smaller error box)
  23. IPN triangulation of GRB021020
  24. GRB 021008, optical observations
  25. IPN triangulation of GRB021016 (small error box)
  26. IPN triangulation of GRB021014 (large error box)
  27. IPN triangulation of GRB021013 (single error box)
  28. GRB 021004: optical spectroscopy on Oct 11
  29. IPN triangulation of GRB021013 (two small error boxes)
  30. GRB021004: High-resolution optical spectroscopy
  31. XRF 020903: flattening of the optical light curve.
  32. GRB021004, UBVRcIc field photometry update
  33. IPN triangulation of GRB021008 (single error box)
  34. GRB 021004 submm observations
  35. IPN triangulation of GRB021008 (two small error boxes)
  36. GRB021004 Chandra HETG Observations
  37. GRB 021004: Optical/NIR Observations
  38. GRB 021004: Additional V-band Polarimetric Observations
  39. GRB021004: optical observation
  40. GRB 021004: Host Galaxy Star Formation Rate
  41. GRB 021004 submm observations
  42. GRB 021004: WC wind?
  43. GRB021004: NIR and Optical observations
  44. GRB 021004: Optical observations, AUDE network
  45. GRB 021004 - VLA Radio Observations
  46. GRB 021004 - Unusual Radio-to-Submm Spectrum
  47. GRB 021004: optical spectroscopy
  48. IPN triangulation of GRB021007 (annulus)
  49. GRB021004: optical observations and predicted break time
  50. GRB021004: BVRc photometry
  51. GRB021004 radio observation
  52. HETE fluences for GRB021004
  53. GRB 021004: Optical Photometry at 2.5 Days
  54. GRB 021004: polarimetric observations
  55. GRB 021004: V-band Polarimetric Observations
  56. GRB021004: Update Bisei photometric data
  57. IRAM Millimeter detection of GRB 021004
  58. GRB 021004 radio observation
  59. GRB 021004: Optical Photometry at 1.5 Days
  60. GRB021004, BVRcIc field photometry
  61. GRB021004: Optical Spectroscopy
  62. GRB 021004 radio search
  63. XRF020903, BVRI field photometry
  64. XRF020903: TNG and Asiago photometry
  65. GRB 020903: Optical observations at RIKEN
  66. XRF 020903: Correction to GCN 1560
  67. XRF 020903: VRI observations
  68. XRF 020903: R band observations
  69. XRF 020903: Archival Optical Images
  70. Radio Observations of XRF 020903: The Missing Link
  71. XRF 020903: Supernova
  72. IPN triangulation of GRB020923 (two error boxes)
  73. IPN triangulation of GRB020914B
  74. IPN triangulation of GRB020911 (2 large error boxes)
  75. GRB 020305: HST/STIS observations
  76. Confirmation of IPN error box for GRB020910
  77. IPN triangulation of GRB020910
  78. IPN GCN Circulars now to be issued without restriction
  79. Single IPN error box for GRB020904
  80. XRF 020903: optical observation at Kyoto
  81. GRB020322 : HST/STIS observations
  82. XRF 020903: Optical observations
  83. IPN triangulation of GRB020904
  84. INTEGRAL GRBs added to GCN
  85. SGR1900+14 burst localized by HETE
  86. GRB020813: High-resolution optical spectroscopy
  87. GRB020812: negative optical observations
  88. GRB 020812: optical observation at Kyoto University
  89. Second epoch K band imaging of GRB 020819
  90. GRB 020813 : HST observations
  91. GRB 020812: early time optical observation at Ouda Station
  92. GRB020813: Magellan BVRI Photometry
  93. GRB 020819: Optical observations
  94. K band observation of GRB 020819
  95. GRB020813: optical and NIR observations
  96. GRB020813: Fading X-ray Afterglow Observed with Chandra
  97. GRB020813, UBVRI field calibration
  98. GRB020812: NIR observations
  99. Polarimetry of GRB020813: evidence for variability
  100. GRB020813 IRAM millimeter observations

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