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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. GRB990123: NIR Observation
  2. GRB990123, ASCA X-ray observation of afterglow
  3. "GRB 990123: New BV Observations"
  4. GRB 990123 Optical Follow-Up
  5. GRB 990123; Addendum to GCN 223
  6. GRB 990123: BATSE Observations
  7. GRB 990123 Keck Spectrum update
  8. GRB990123 IPN annulus
  9. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  10. GRB990123 Optical Observations
  11. GRB 990123 Spectroscopic Redshifts
  12. GRB 990123: New Optical Observations, Decay Measure
  13. GRB 990123 Optical Follow-Up
  14. GRB 990123: Possible Gravitationally Lensed Burst?
  15. GRB990123, optical observation
  16. GRB 990123 optical observations
  17. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  18. GRB 990123 radio observations
  19. GRB 990123, new radio source
  20. GRB990123 optical observations
  21. GRB990123, Optical observation
  22. GRB 990123: Optical Decay Slope
  23. GRB 990123 r-band photometry
  24. GRB 990123 Optical Follow-up
  25. GRB990123, early optical counterpart detection
  26. GRB990123 Optical Observation
  27. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  28. GRB990123, refined SAX-WFC position
  29. GRB 990123: Bright New Source, Possible Optical Transient
  30. GRB 990123, Radio observations
  31. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  32. SN 1999E & GRB 980919
  33. Possible identification of SN1999E with GRB980910
  34. Optical Observations of GRB 981220
  35. GRB 981226: radio variable
  36. GRB981220
  37. GRB981220, Correction to GCN 179
  38. GRB981220, Optical Observations
  39. GRB 981220 Optical observations
  40. GRB 981226 Optical Observations
  41. GRB 980613: Spectroscopy of the host galaxy
  42. GRB981226, sub-millimeter observations
  43. GRB981220, sub-millimeter observations
  44. GRB 981220 and GRB 981226, optical observations
  45. GRB981226 Optical Observations
  46. GRB981226 BeppoSAX follow up
  47. GRB 981226 radio observations
  48. GRB 981226
  49. GRB 981226 optical observations
  50. radio observations of GRB 981226
  51. GRB981220 B, R and I band observations
  52. GRB981226, BeppoSAX-NFI follow-up
  53. Optical Observations of GRB981226
  54. GRB 981220:Optical Observations
  55. GRB 981220 optical R and I observations
  56. GRB981226, BeppoSAX Christmas GRB
  57. GRB 981226 - Infrared Observations
  58. GRB 981226 optical observations
  59. GRB 981220
  60. GRB 981220, radio observations
  61. GRB981226 Optical Observation
  62. GRB 981220, radio observations
  63. GRB 981220: BeppoSAX/GRBM results
  64. GRB981220 I-band Observations
  65. GRB981220 Optical Observations
  66. GRB 981220
  67. GRB 981220 Optical Observations
  68. GRB 981220, optical observations
  69. GRB 980326/Host Galaxy
  70. GRB981220 IPN error box
  71. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  72. BeppoSAX NFI Observation of GRB980425
  73. GRB980329 R,I flux calibration and R,I,K upper limits
  74. GRB980425 Optical Follow-up
  75. GRB980425: X-ray revised positions
  76. GRB 980923 BATSE Observations
  77. SGR1900+14, BeppoSAX-GRBM observations
  78. GRB980703 Very Long Baseline Interferometry
  79. GRB970508 optical observations
  80. GRB971214, association with a Galactic star?
  81. Optical Observations of the Host Galaxy of GRB 980519
  82. GRB980519, Optical Observations
  83. GRB980703, Host galaxy multicolor photometry
  84. GRB980703 - BeppoSAX/GRBM detection
  85. GRB 980703 (NFI observations)
  86. GRB980703 optical photometry
  87. GRB 980703: BATSE Observations
  88. GRB980703 optical observations
  89. GRB980703: Radio transient
  90. GRB980703 H-band Observations
  91. GRB 980703: Spectrum of the proposed optical counterpart
  92. RXTE Observation of GRB 980706
  93. GRB980703: Spectrum of the proposed optical counterpart
  94. GRB980703 Transient Optical Follow-Up
  95. GRB980703: LOTIS observation at early times
  96. GRB980613 Optical Observations
  97. GRB 980703
  98. GRB980703 (I band observations)
  99. GRB 980703 H-band Observations
  100. GRB980703 (optical R observations)

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