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

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