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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"
  1. GRB980519 BATSE Observations
  2. GRB970519, optical follow-up at Schmidt Calern
  3. GRB980519 optical observations
  4. GRB980519 Optical Observations
  5. GRB980519 Optical Observations
  6. GRB980519 IPN POSITION
  7. GRB980519 Optical Observations
  8. GRB 980519 Optical Observations
  9. GRB980519 optical observations
  10. GRB980515, BeppoSAX IAUC to be submitted
  11. BATSE on-board GRB trigger change
  12. GRB980519, BeppoSAX-WFC updated position
  13. GRB980519, BeppoSAX-WFC position
  14. GRB980515: SAX-WFC updated position
  15. BeppoSAX GRB ALERT: updated position of grb980515
  16. GRB 980425 Radio Light Curve
  17. GRB 980425 Brightness Temperature
  18. BSAX Observations of GRB980425 field
  19. IPN web site of GRBs
  20. GRB980425 BATSE observations
  21. SAX J0840.7+2248 Optical Observations
  22. GRB 980425 optical observations
  23. GRB980425: optical obs.
  24. GRB980425: Radio Observations
  25. GRB 980425 optical observations
  26. report on BSAX observations of GRB980425
  27. GRB 980425 optical observations
  28. GRB 980329 ROSAT observation
  29. GRB980326 X-ray Observations
  30. GRB980326, optical observations
  31. GRB980326, optical observations
  32. GRB980329, Fading IR counterpart to radio source
  33. GRByymmdd, Announcement of automation
  34. GRB980326 IPN annulus
  35. GRB980329
  36. GRB980329 Keck K-band observations
  37. GRB980329 sub-millimeter observations
  38. GRB980329 IPN annulus
  39. GRB980329 optical observations
  40. GRB980329 near-IR observations
  41. GRB980329 near-IR observations
  42. GRB980329 optical observations
  43. GRB980329 infrared observations
  44. GRB980329 optical observations
  45. GRB980326 optical observations
  46. GRB980329 optical observations
  47. GRB980329 VLA observations
  48. GRB980329 near IR observations
  49. GRB980329 optical observations
  50. GRB980329 optical observations
  51. GRB980329 optical observations
  52. GRB980326 optical observations
  53. GRB980326 optical observations
  54. GRB980326 optical observations
  55. GRB980326 optical observations
  56. GRB970508 SAO RAS optical observations
  57. Optical Observations of GRB 970508
  58. GRB 971214: Redshift from Keck Observations
  59. Near-IR follow-up on GRB 971227
  60. GRB971214: Keck R & I-band Observations
  61. GRB 971227: Optical Observations
  62. Optical Observations of the GRB 971227 field
  63. Optical Observations on GRB 971227
  64. GRB971227: Plaskett R-band observations
  65. GRB 971227: Optical clarifications
  66. Optical Observations for GRB 971227
  67. GRB971227: Further CAHA R-band images
  68. GRB971227: LOTIS observations
  69. GRB 971227: CAHA R-band images
  70. GRB 971227: Optical observations
  71. GRB971214: Optical Observations and Calibrations
  72. Sub-millimeter Observations of GRB 971214 at the JCMT
  73. GRB 971214: EUVE Observations
  74. GRB 971214: Redshift from Keck Optical Observations
  75. GRB 971214: Redshift from Keck Optical Observations
  76. GRB 971214: Apache Point Observatory Optical Observations
  77. GRB 971214: KPNO Optical Observations
  78. Optical Observations of GRB 971214 at Keck
  79. GRB 971214: Optical Observations
  80. Radio Observations of GRB 971214 at the VLA
  81. GRB 971214: USNOFS Observations Summary
  82. GRB 971024: KPNO Optical Observations Summary
  83. GRB 971024: Refined analysis by USNOFS Observations
  84. GRB 971024: KPNO Optical Observations
  85. GRB 971024: USNO Observations
  86. GRB 970925: BATSE Localization
  87. IRAS 18119-1342 and the possible new SGR
  88. Possible new SGR from US Naval Observatory
  89. RXTE Observations of SGR 1814-13
  90. GRB 970828: Palomar Observations
  91. GRB 970228: Keck/LRIS Optical Observations

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