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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"

25013 results found.

  1. XRF 020903: Archival Optical Images
  2. Radio Observations of XRF 020903: The Missing Link
  3. XRF 020903: Supernova
  4. IPN triangulation of GRB020923 (two error boxes)
  5. IPN triangulation of GRB020914B
  6. IPN triangulation of GRB020911 (2 large error boxes)
  7. GRB 020305: HST/STIS observations
  8. Confirmation of IPN error box for GRB020910
  9. IPN triangulation of GRB020910
  10. IPN GCN Circulars now to be issued without restriction
  11. Single IPN error box for GRB020904
  12. XRF 020903: optical observation at Kyoto
  13. GRB020322 : HST/STIS observations
  14. XRF 020903: Optical observations
  15. IPN triangulation of GRB020904
  16. INTEGRAL GRBs added to GCN
  17. SGR1900+14 burst localized by HETE
  18. GRB020813: High-resolution optical spectroscopy
  19. GRB020812: negative optical observations
  20. GRB 020812: optical observation at Kyoto University
  21. Second epoch K band imaging of GRB 020819
  22. GRB 020813 : HST observations
  23. GRB 020812: early time optical observation at Ouda Station
  24. GRB020813: Magellan BVRI Photometry
  25. GRB 020819: Optical observations
  26. K band observation of GRB 020819
  27. GRB020813: optical and NIR observations
  28. GRB020813: Fading X-ray Afterglow Observed with Chandra
  29. GRB020813, UBVRI field calibration
  30. GRB020812: NIR observations
  31. Polarimetry of GRB020813: evidence for variability
  32. GRB020813 IRAM millimeter observations
  33. GRB020812: optical observations
  34. GRB020813: High-Resolution Optical Observations
  35. GRB 020812: optical observation at Bisei
  36. GRB020813: Early Time Magnitude
  37. Millimeter observation of GRB 020813
  38. GRB020812: optical observations
  39. GRB 020813 : KISO multiband optical observations
  40. GRB020813, optical observations
  41. IPN error box for GRB020813
  42. GRB020813, astrometric position
  43. Spectropolarimetry of GRB 020813
  44. GRB 020812 optical observation
  45. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  46. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  47. HST Imaging of the Host of GRB 011121
  48. GRB020801, optical afterglow candidate
  49. GRB020331: Late-time Optical Light Curve (re-submission)
  50. GRB020331: Late-time Optical Light Curve
  51. IPN triangulation of GRB020714
  52. IPN triangulation of GRB020715 (=GRB150702)
  53. IPN triangulation of GRB020714
  54. IPN triangulation of GRB150702
  55. GRB 020410: Discovery of Probable OT by HST
  56. GRB 020124, HST observations of the fading afterglow
  57. IPN triangulation of GRB020708
  58. IPN triangulation of GRB020708
  59. Correction to IPN error box for GRB020706
  60. IPN triangulation of GRB020706
  61. GRB 020705: Optical observations
  62. GRB 020625, optical observations
  63. GRB 020625: Optical observations
  64. GRB 020531: optical photometry of Chandra sources
  65. GRB020625 (=H2081): A Long Burst Localized by HETE
  66. The Probable Host Galaxy of GRB/XRF 020427
  67. GRB/XRF 020427, detection of an underlying system with the VLT
  68. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  69. AXP 1E2259+586 optical observations
  70. Fading Optical Source in the Field of GRB020531
  71. GRB 020531, INT+WFC deep optical upper limits
  72. SGR-like Bursts from the AXP 1E 2259+586
  73. GRB020405: polarimetric observations
  74. GRB 020531, simultaneous optical observations
  75. GRB 020531/Candidate Redshift
  76. GRB020531: Detection of Candidate Host Galaxy
  77. GRB020531: Second epoch Chandra observations
  78. GRB020604, optical observations
  79. GRB020604, BVRcIc field photometry
  80. GRB020603, BVRcIc field observations
  81. GRB020531, BVRcIc field photometry
  82. GRB020531 Optical Observations
  83. GRB020531: Observations with the Chandra X-ray Observatory
  84. GRB020531, optical observations
  85. GRB020531: optical observations
  86. GRB020531(=H2042): Optical Observations
  87. GRB020531(=H2042): Optical Observations
  88. GRB020531: Optical observations
  89. GRB020531(=H2042): A Short, Hard Burst Localized by HETE
  90. GRB020525, optical observations
  91. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  92. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  93. HST detection of the likely host galaxy of GRB 020124
  94. GRB020405 field photometry at ESO
  95. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  96. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  97. GRB020321 : Optical observations.
  98. XRF 020427
  99. GRB 020124: Optical observations
  100. IPN triangulation of GRB020418

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